Piik/tests/client-state.test.ts

import { afterEach, describe, expect, it, vi } from "vitest";

import {
  DEFAULT_ROUTE_POLICY,
  SIGNALING_PROTOCOL,
  type QualitySettings,
} from "../src/shared/protocol.ts";

import {
  ApiError,
  authenticateSiteAccess,
  createRoom,
  getSiteAccess,
  replaceOwnedRoom,
} from "../src/client/lib/api.ts";
import {
  defaultHostDisplayName,
  defaultViewerDisplayName,
  readDisplayName,
  saveDisplayName,
} from "../src/client/lib/display-name.ts";
import { setCopy } from "../src/client/ui/copy.ts";
import {
  clearHostRoom,
  getStableClientId,
  isValidRoomId,
  parseAppRoute,
  mergeAuthenticatedHostRoom,
  readHostRoom,
  readPreferredRoomId,
  readViewerGrant,
  readViewerRoute,
  replaceViewerInvite,
  roomRouteForExplicitEntry,
  roomRouteFromInput,
  writeHostRoom,
  writePreferredRoom,
} from "../src/client/lib/session.ts";
import {
  shouldReconnectSignaling,
  SignalingClient,
} from "../src/client/lib/signaling.ts";
import { deriveParticipantTopology } from "../src/client/lib/participant-topology.ts";
import {
  labelParticipantSnapshot,
  labelViewerParticipants,
  labelViewerPresence,
} from "../src/client/lib/viewer-presence.ts";
import { qualityEvidenceWindowFromMetrics } from "../src/client/media/viewer-quality-evidence.ts";
import {
  collectConnectionMetrics,
  collectConnectionMetricsFromReport,
  collectNativeSenderQualityFromReport,
  createNativeSenderQualityAccumulator,
  createStatsAccumulator,
} from "../src/client/webrtc/stats.ts";

afterEach(() => {
  vi.useRealTimers();
  vi.unstubAllGlobals();
  setCopy({ lang: "zh", vis: false });
});

describe("browser-local display name", () => {
  it("localizes text defaults and uses visual emoji identities", () => {
    setCopy({ lang: "zh", vis: false });
    expect(defaultViewerDisplayName("viewer-abcdef", false)).toBe("观众");
    expect(defaultHostDisplayName("host-abcdef", false)).toBe("分享者-abcdef");

    setCopy({ lang: "en", vis: false });
    expect(defaultViewerDisplayName("viewer-abcdef", false)).toBe("Viewer");
    expect(defaultHostDisplayName("host-abcdef", false)).toBe("Host-abcdef");

    expect(defaultViewerDisplayName("viewer-abcdef", true)).toBe("👤-abcdef");
    expect(defaultHostDisplayName("host-abcdef", true)).toBe("👑-abcdef");
  });

  it("stores only the canonical preference and falls back when cleared", () => {
    const values = new Map<string, string>();
    vi.stubGlobal("window", {
      localStorage: {
        getItem: (key: string) => values.get(key) ?? null,
        setItem: (key: string, value: string) => values.set(key, value),
        removeItem: (key: string) => values.delete(key),
      },
    });

    expect(saveDisplayName("  Cafe\u0301\u00a0玩家 ")).toBe("Café 玩家");
    expect(readDisplayName()).toBe("Café 玩家");
    expect(saveDisplayName("\u202ehidden")).toBeNull();
    expect(saveDisplayName("\n")).toBeNull();
    expect(readDisplayName()).toBe("Café 玩家");
    expect(saveDisplayName("   ")).toBe("观众");
    expect(readDisplayName()).toBe("观众");
  });

  it("extends only colliding room-scoped peer ID suffixes", () => {
    const labeled = labelViewerPresence([
      {
        role: "viewer",
        peerId: "viewer_AAAAAAsuffix",
        displayName: "同名",
        upstream: { kind: "peer", peerId: "host_12345678" },
      },
      {
        role: "viewer",
        peerId: "viewer_BBBBBBsuffix",
        displayName: "同名",
        upstream: { kind: "peer", peerId: "viewer_AAAAAAsuffix" },
      },
      {
        role: "viewer",
        peerId: "viewer_independent",
        displayName: "朋友",
        upstream: { kind: "sfu" },
      },
    ]);

    expect(labeled[0].peerIdSuffix.length).toBeGreaterThan(6);
    expect(labeled[1].peerIdSuffix.length).toBeGreaterThan(6);
    expect(labeled[0].peerIdSuffix).not.toBe(labeled[1].peerIdSuffix);
    expect(labeled[2].peerIdSuffix).toHaveLength(6);
    expect(labeled[2].label).toBe("朋友");
    expect(labeled[0].label).toContain("同名 (");
  });

  it("keeps the shortest hidden suffix for distinct display names", () => {
    const labeled = labelViewerPresence([
      {
        role: "viewer",
        peerId: "viewer_AAAAAAsuffix",
        displayName: "甲",
        upstream: { kind: "sfu" },
      },
      {
        role: "viewer",
        peerId: "viewer_BBBBBBsuffix",
        displayName: "乙",
        upstream: { kind: "sfu" },
      },
    ]);

    expect(labeled.map((viewer) => viewer.label)).toEqual(["甲", "乙"]);
    expect(labeled.map((viewer) => viewer.peerIdSuffix.length)).toEqual([6, 6]);
  });

  it("uses the minimum suffix when duplicate names are already distinct", () => {
    const labeled = labelViewerPresence([
      {
        role: "viewer",
        peerId: "viewer_AAAAAA111111",
        displayName: "同名",
        upstream: { kind: "none" },
      },
      {
        role: "viewer",
        peerId: "viewer_BBBBBB222222",
        displayName: "同名",
        upstream: { kind: "none" },
      },
    ]);

    expect(labeled.map((viewer) => viewer.peerIdSuffix)).toEqual([
      "111111",
      "222222",
    ]);
    expect(labeled.map((viewer) => viewer.label)).toEqual([
      "同名 (111111)",
      "同名 (222222)",
    ]);
  });

  it("labels every Viewer in a participant snapshot without including the Host", () => {
    const labeled = labelViewerParticipants([
      {
        role: "host",
        peerId: "host_12345678",
        displayName: "分享者",
        upstream: { kind: "none" },
      },
      {
        role: "viewer",
        peerId: "viewer_111111",
        displayName: "朋友甲",
        upstream: { kind: "peer", peerId: "host_12345678" },
      },
      {
        role: "viewer",
        peerId: "viewer_222222",
        displayName: "朋友乙",
        upstream: { kind: "sfu" },
      },
    ]);

    expect(labeled.map((viewer) => viewer.label)).toEqual([
      "朋友甲",
      "朋友乙",
    ]);
  });

  it("labels Host and Viewer name collisions before splitting roles", () => {
    const labeled = labelParticipantSnapshot([
      {
        role: "host",
        peerId: "host_123456",
        displayName: "同名",
        upstream: { kind: "none" },
      },
      {
        role: "viewer",
        peerId: "viewer_654321",
        displayName: "同名",
        upstream: { kind: "peer", peerId: "host_123456" },
      },
      {
        role: "viewer",
        peerId: "viewer_789012",
        displayName: "唯一名称",
        upstream: { kind: "sfu" },
      },
    ]);

    expect(labeled.host?.label).toBe("同名 (123456)");
    expect(labeled.viewers.map((viewer) => viewer.label)).toEqual([
      "同名 (654321)",
      "唯一名称",
    ]);
  });

  it("derives exact peer and SFU branches without guessing orphaned routes", () => {
    const viewer = (
      peerId: string,
      upstream:
        | { kind: "none" }
        | { kind: "sfu" }
        | { kind: "peer"; peerId: string },
    ) => ({ role: "viewer" as const, peerId, displayName: peerId, upstream });
    const topology = deriveParticipantTopology(
      "host_12345678",
      labelViewerPresence([
        viewer("viewer_root_1", { kind: "peer", peerId: "host_12345678" }),
        viewer("viewer_child_1", { kind: "peer", peerId: "viewer_root_1" }),
        viewer("viewer_sfu_1", { kind: "sfu" }),
        viewer("viewer_sfu_child", {
          kind: "peer",
          peerId: "viewer_sfu_1",
        }),
        viewer("viewer_pending", { kind: "none" }),
        viewer("viewer_orphan", { kind: "peer", peerId: "viewer_offline" }),
      ]),
    );

    expect(topology.peerRoots[0].viewer.peerId).toBe("viewer_root_1");
    expect(topology.peerRoots[0].children[0].viewer.peerId).toBe(
      "viewer_child_1",
    );
    expect(topology.sfuRoots[0].children[0].viewer.peerId).toBe(
      "viewer_sfu_child",
    );
    expect(topology.pending.map((entry) => entry.peerId)).toEqual([
      "viewer_orphan",
      "viewer_pending",
    ]);
  });
});

describe("client session identity", () => {
  it("works without secure-context-only crypto.randomUUID", () => {
    const values = new Map<string, string>();
    vi.stubGlobal("window", {
      sessionStorage: {
        getItem: (key: string) => values.get(key) ?? null,
        setItem: (key: string, value: string) => values.set(key, value),
      },
    });
    vi.stubGlobal("crypto", {
      getRandomValues: (bytes: Uint8Array) => {
        bytes.fill(0xab);
        return bytes;
      },
    });

    const first = getStableClientId("viewer", "room-id-1234");

    expect(first).toBe("ab".repeat(16));
    expect(getStableClientId("viewer", "room-id-1234")).toBe(first);
  });

  it("persists one validated host room across browser sessions", () => {
    const values = new Map<string, string>();
    vi.stubGlobal("window", {
      localStorage: {
        getItem: (key: string) => values.get(key) ?? null,
        setItem: (key: string, value: string) => values.set(key, value),
        removeItem: (key: string) => values.delete(key),
      },
    });
    const room = {
      roomId: "1234",
      hostToken: "a".repeat(32),
      inviteUrl: `https://share.test/r/1234#v=${"b".repeat(21)}A`,
      codeEntryPolicy: "open" as const,
      expiresAt: null,
      roomLeaseSeconds: 3_600,
    };

    writeHostRoom(room);

    expect(readHostRoom()).toEqual({
      roomId: "1234",
      hostToken: "a".repeat(32),
      canonicalUrl: "https://share.test/r/1234",
      expiresAt: null,
      roomLeaseSeconds: 3_600,
    });
    expect(values.get("screener:host-room:v1")).toBe(
      JSON.stringify({
        roomId: "1234",
        hostToken: "a".repeat(32),
        expiresAt: null,
        roomLeaseSeconds: 3_600,
        inviteUrl: "https://share.test/r/1234",
      }),
    );
    expect([...values.values()].join(" ")).not.toContain(`${"b".repeat(21)}A`);
    clearHostRoom();
    expect(readHostRoom()).toBeNull();
  });

  it("reclaims a deployed Host ownership record through the stable shape", () => {
    const values = new Map<string, string>([
      [
        "screener:host-room:v1",
        JSON.stringify({
          roomId: "1234",
          hostToken: "h".repeat(32),
          inviteUrl: "https://share.test/r/1234",
          expiresAt: null,
          roomLeaseSeconds: 3_600,
        }),
      ],
    ]);
    vi.stubGlobal("window", {
      localStorage: {
        getItem: (key: string) => values.get(key) ?? null,
        setItem: (key: string, value: string) => values.set(key, value),
        removeItem: (key: string) => values.delete(key),
      },
    });

    expect(readHostRoom()).toEqual({
      roomId: "1234",
      hostToken: "h".repeat(32),
      canonicalUrl: "https://share.test/r/1234",
      expiresAt: null,
      roomLeaseSeconds: 3_600,
    });
  });

  it("keeps expired host records for server judgment and discards malformed records", () => {
    const values = new Map<string, string>();
    const removeItem = vi.fn((key: string) => values.delete(key));
    vi.stubGlobal("window", {
      localStorage: {
        getItem: (key: string) => values.get(key) ?? null,
        setItem: (key: string, value: string) => values.set(key, value),
        removeItem,
      },
    });
    const expired = {
      roomId: "1234",
      hostToken: "b".repeat(32),
      canonicalUrl: "https://share.test/r/1234",
      expiresAt: "2026-08-18T00:00:00.000Z",
      roomLeaseSeconds: 3_600,
    };

    writeHostRoom(expired);
    expect(readHostRoom()).toMatchObject({ roomId: "1234" });
    expect(removeItem).not.toHaveBeenCalled();

    values.set("screener:host-room:v1", "not-json");
    expect(readHostRoom()).toBeNull();
    expect(removeItem).toHaveBeenCalledOnce();
  });

  it("consumes a Viewer grant fragment once into room-scoped session storage", () => {
    const values = new Map<string, string>();
    const replaceState = vi.fn();
    const grant = `${"c".repeat(21)}g`;
    vi.stubGlobal("window", {
      location: new URL(`https://share.test/r/1234#v=${grant}`),
      history: { state: { navigation: 1 }, replaceState },
      sessionStorage: {
        getItem: (key: string) => values.get(key) ?? null,
        setItem: (key: string, value: string) => values.set(key, value),
        removeItem: (key: string) => values.delete(key),
      },
    });

    expect(readViewerRoute()).toEqual({ roomId: "1234", viewerGrant: grant });
    expect(values.get("screener:viewer-grant:1234")).toBe(grant);
    expect(replaceState).toHaveBeenCalledWith(
      { navigation: 1 },
      "",
      "/r/1234",
    );
    expect(readViewerGrant("8")).toBeNull();
  });

  it("fails malformed Viewer fragments closed without leaking across rooms", () => {
    const values = new Map<string, string>();
    const oldGrant = `${"d".repeat(21)}w`;
    values.set("screener:viewer-grant:1234", oldGrant);
    vi.stubGlobal("window", {
      location: new URL("https://share.test/r/1234#v=malformed"),
      history: { state: null, replaceState: vi.fn() },
      sessionStorage: {
        getItem: (key: string) => values.get(key) ?? null,
        setItem: (key: string, value: string) => values.set(key, value),
        removeItem: (key: string) => values.delete(key),
      },
    });

    expect(readViewerRoute()).toEqual({ roomId: "1234" });
    expect(readViewerGrant("1234")).toBeNull();
    replaceViewerInvite("1234", `https://share.test/r/1234#v=${"e".repeat(21)}Q`);
    expect(readViewerGrant("1234")).toBe(`${"e".repeat(21)}Q`);
    replaceViewerInvite("1234", `https://share.test/r/5678#v=${"f".repeat(21)}A`);
    expect(readViewerGrant("1234")).toBeNull();
    expect(readViewerGrant("5678")).toBeNull();
  });

  it("persists a rotated Viewer invitation across reload and clears it on revoke", () => {
    const values = new Map<string, string>();
    vi.stubGlobal("window", {
      sessionStorage: {
        getItem: (key: string) => values.get(key) ?? null,
        setItem: (key: string, value: string) => values.set(key, value),
        removeItem: (key: string) => values.delete(key),
      },
    });
    const firstGrant = `${"g".repeat(21)}g`;
    const rotatedGrant = `${"h".repeat(21)}w`;

    replaceViewerInvite("1234", `https://share.test/r/1234#v=${firstGrant}`);
    replaceViewerInvite("1234", `https://share.test/r/1234#v=${rotatedGrant}`);

    expect(readViewerGrant("1234")).toBe(rotatedGrant);
    expect(readViewerGrant("1234")).toBe(rotatedGrant);

    replaceViewerInvite("1234", null);
    expect(readViewerGrant("1234")).toBeNull();
  });

  it("keeps the latest rotated or revoked invite through Host re-authentication", () => {
    const values = new Map<string, string>();
    vi.stubGlobal("window", {
      sessionStorage: {
        getItem: (key: string) => values.get(key) ?? null,
        setItem: (key: string, value: string) => values.set(key, value),
        removeItem: (key: string) => values.delete(key),
      },
    });
    const oldInvite = `https://share.test/r/1234#v=${"i".repeat(21)}Q`;
    const rotatedInvite = `https://share.test/r/1234#v=${"j".repeat(21)}A`;
    replaceViewerInvite("1234", oldInvite);
    const activeRoom = {
      roomId: "1234",
      hostToken: "h".repeat(32),
      canonicalUrl: "https://share.test/r/1234",
      expiresAt: null,
      roomLeaseSeconds: 3_600,
      codeEntryPolicy: "open" as const,
      inviteUrl: oldInvite,
    };

    expect(
      mergeAuthenticatedHostRoom(
        { ...activeRoom, inviteUrl: rotatedInvite },
        activeRoom.roomId,
        null,
        "open",
      )?.inviteUrl,
    ).toBe(rotatedInvite);
    expect(
      mergeAuthenticatedHostRoom(
        { ...activeRoom, inviteUrl: null },
        activeRoom.roomId,
        null,
        "open",
      )?.inviteUrl,
    ).toBe(oldInvite);
    replaceViewerInvite(activeRoom.roomId, null);
    expect(
      mergeAuthenticatedHostRoom(
        { ...activeRoom, inviteUrl: null },
        activeRoom.roomId,
        null,
        "open",
      )?.inviteUrl,
    ).toBeNull();
  });

  it("keeps the latest preferred room without a client expiry", () => {
    const values = new Map<string, string>();
    vi.stubGlobal("window", {
      localStorage: {
        getItem: (key: string) => values.get(key) ?? null,
        setItem: (key: string, value: string) => values.set(key, value),
        removeItem: (key: string) => values.delete(key),
      },
    });

    writePreferredRoom("4321");

    clearHostRoom();
    expect(readPreferredRoomId()).toBe("4321");
    expect(values.get("screener:host-room-preference:v1")).toBe(
      JSON.stringify({ roomId: "4321" }),
    );
  });

  it("removes a legacy Viewer grant from room-scoped session storage", () => {
    const values = new Map<string, string>([
      ["screener:viewer-grant:1234", `g1.1234.1.${"f".repeat(43)}`],
    ]);
    const removeItem = vi.fn((key: string) => values.delete(key));
    vi.stubGlobal("window", {
      sessionStorage: {
        getItem: (key: string) => values.get(key) ?? null,
        setItem: (key: string, value: string) => values.set(key, value),
        removeItem,
      },
    });

    expect(readViewerGrant("1234")).toBeNull();
    expect(removeItem).toHaveBeenCalledWith("screener:viewer-grant:1234");
  });
});

describe("site access API", () => {
  it("checks and authenticates site access without a request body", async () => {
    const fetchMock = vi
      .fn<typeof fetch>()
      .mockResolvedValueOnce(
        new Response(JSON.stringify({ required: true, authenticated: false }), {
          status: 200,
          headers: { "Content-Type": "application/json" },
        }),
      )
      .mockResolvedValueOnce(
        new Response(JSON.stringify({ required: true, authenticated: true }), {
          status: 200,
          headers: { "Content-Type": "application/json" },
        }),
      );
    vi.stubGlobal("fetch", fetchMock);

    await expect(getSiteAccess()).resolves.toEqual({
      required: true,
      authenticated: false,
    });
    await expect(authenticateSiteAccess("  instance-password  ")).resolves.toEqual({
      required: true,
      authenticated: true,
    });

    expect(fetchMock.mock.calls[0]).toEqual([
      "/api/site-access",
      { headers: { Accept: "application/json" } },
    ]);
    const post = fetchMock.mock.calls[1][1];
    expect(post?.method).toBe("POST");
    expect(post?.body).toBeUndefined();
    expect(new Headers(post?.headers).get("Authorization")).toBe(
      "Bearer instance-password",
    );
  });

  it("uses a clear Chinese message for a rejected password", async () => {
    vi.stubGlobal(
      "fetch",
      vi.fn<typeof fetch>().mockResolvedValue(
        new Response(JSON.stringify({ error: "Unauthorized" }), {
          status: 401,
          headers: { "Content-Type": "application/json" },
        }),
      ),
    );

    await expect(authenticateSiteAccess("wrong-password")).rejects.toMatchObject({
      status: 401,
      message: "站点口令不正确，请重试",
    });
  });

  it("does not expose an English server error body to the access page", async () => {
    vi.stubGlobal(
      "fetch",
      vi.fn<typeof fetch>().mockResolvedValue(
        new Response(JSON.stringify({ error: "Internal Server Error" }), {
          status: 503,
          headers: { "Content-Type": "application/json" },
        }),
      ),
    );

    await expect(getSiteAccess()).rejects.toMatchObject({
      status: 503,
      message: "站点验证服务暂时不可用 (503)",
    });
  });

  it("does not send a raw bearer token when creating a room by default", async () => {
    const fetchMock = vi.fn<typeof fetch>().mockResolvedValue(
      new Response(JSON.stringify({ error: "test response" }), {
        status: 500,
        headers: { "Content-Type": "application/json" },
      }),
    );
    vi.stubGlobal("fetch", fetchMock);

    await expect(createRoom("open", null)).rejects.toBeInstanceOf(ApiError);

    const headers = new Headers(fetchMock.mock.calls[0][1]?.headers);
    expect(headers.has("Authorization")).toBe(false);
    expect(fetchMock.mock.calls[0][1]?.body).toBe(
      JSON.stringify({ codeEntryPolicy: "open" }),
    );
  });

  it("sends only the preferred room code when one is current", async () => {
    const fetchMock = vi.fn<typeof fetch>().mockResolvedValue(
      new Response(JSON.stringify({ error: "test response" }), {
        status: 500,
        headers: { "Content-Type": "application/json" },
      }),
    );
    vi.stubGlobal("fetch", fetchMock);

    await expect(createRoom("open", null, "4321")).rejects.toBeInstanceOf(
      ApiError,
    );

    expect(fetchMock.mock.calls[0][1]?.body).toBe(
      JSON.stringify({ codeEntryPolicy: "open", preferredRoomId: "4321" }),
    );
  });

  it("sends exact Host authority and no preferred code for room replacement", async () => {
    const fetchMock = vi.fn<typeof fetch>().mockResolvedValue(
      new Response(JSON.stringify({ error: "test response" }), {
        status: 500,
        headers: { "Content-Type": "application/json" },
      }),
    );
    vi.stubGlobal("fetch", fetchMock);

    await expect(
      replaceOwnedRoom("4321", "host-token", "private", "room-password"),
    ).rejects.toBeInstanceOf(ApiError);

    expect(fetchMock.mock.calls[0][0]).toBe("/api/rooms/4321/replacement");
    const headers = new Headers(fetchMock.mock.calls[0][1]?.headers);
    expect(headers.get("Authorization")).toBe("Bearer host-token");
    expect(fetchMock.mock.calls[0][1]?.body).toBe(
      JSON.stringify({
        codeEntryPolicy: "private",
        roomPassword: "room-password",
      }),
    );
  });

  it("accepts an active room with a lease deadline", async () => {
    const room = {
      roomId: "1234",
      hostToken: "c".repeat(32),
      inviteUrl: `https://share.test/r/1234#v=${"f".repeat(21)}A`,
      codeEntryPolicy: "open",
      expiresAt: "2026-08-24T00:00:00.000Z",
      roomLeaseSeconds: 86_400,
    };
    vi.stubGlobal(
      "fetch",
      vi.fn<typeof fetch>().mockResolvedValue(
        new Response(JSON.stringify(room), {
          status: 201,
          headers: { "Content-Type": "application/json" },
        }),
      ),
    );

    await expect(createRoom("open", null)).resolves.toEqual(room);
  });
});

describe("room codes", () => {
  it("accepts exactly four decimal digits without a leading zero", () => {
    expect(isValidRoomId("1000")).toBe(true);
    expect(isValidRoomId("9999")).toBe(true);
    expect(isValidRoomId("123")).toBe(false);
    expect(isValidRoomId("12345")).toBe(false);
    expect(isValidRoomId("0")).toBe(false);
    expect(isValidRoomId("0123")).toBe(false);
    expect(isValidRoomId("123a")).toBe(false);
    expect(roomRouteFromInput("1234")).toBe("/r/1234");
    expect(roomRouteFromInput(" 1234 ")).toBeNull();
    expect(roomRouteFromInput("１２３４")).toBeNull();
    expect(roomRouteFromInput("0123")).toBeNull();
  });

  it("drops only the stored grant for an explicit valid room-code entry", () => {
    const values = new Map<string, string>([
      ["screener:viewer-grant:1234", "AAAAAAAAAAAAAAAAAAAAAA"],
      ["screener:viewer-grant:5678", "AAAAAAAAAAAAAAAAAAAAAA"],
    ]);
    vi.stubGlobal("window", {
      sessionStorage: {
        removeItem: (key: string) => values.delete(key),
      },
    });

    expect(roomRouteForExplicitEntry("1234")).toBe("/r/1234");
    expect(values.has("screener:viewer-grant:1234")).toBe(false);
    expect(values.has("screener:viewer-grant:5678")).toBe(true);

    expect(roomRouteForExplicitEntry(" 5678 ")).toBeNull();
    expect(values.has("screener:viewer-grant:5678")).toBe(true);
  });

  it("classifies routes without normalizing malformed room input", () => {
    expect(parseAppRoute("/")).toEqual({ kind: "host" });
    expect(parseAppRoute("/join")).toEqual({ kind: "join" });
    expect(parseAppRoute("/join/")).toEqual({ kind: "join" });
    expect(parseAppRoute("/r/1000")).toEqual({
      kind: "viewer",
      roomId: "1000",
    });
    expect(parseAppRoute("/r/9999/")).toEqual({
      kind: "viewer",
      roomId: "9999",
    });
    for (const pathname of [
      "/r",
      "/r/",
      "/r/123",
      "/r/12345",
      "/r/0000",
      "/r/abcd",
      "/r/１２３４",
      "/r/1234/extra",
    ]) {
      expect(parseAppRoute(pathname)).toEqual({ kind: "malformed-room" });
    }
    expect(parseAppRoute("/other")).toEqual({ kind: "unknown" });
  });
});

describe("client signaling recovery policy", () => {
  it("does not reconnect a session that another tab replaced", () => {
    expect(shouldReconnectSignaling(4001)).toBe(false);
    expect(shouldReconnectSignaling(4003)).toBe(false);
    expect(shouldReconnectSignaling(4004)).toBe(false);
    expect(shouldReconnectSignaling(1008)).toBe(false);
    expect(shouldReconnectSignaling(1012)).toBe(true);
    expect(shouldReconnectSignaling(4002)).toBe(true);
    expect(shouldReconnectSignaling(1006)).toBe(true);
  });

  it("uses the common reconnect state for a recoverable close", () => {
    vi.useFakeTimers();
    const sockets: FakeWebSocket[] = [];
    class FakeWebSocket extends EventTarget {
      static readonly OPEN = 1;
      static readonly CLOSING = 2;
      readyState = FakeWebSocket.OPEN;
      readonly send = vi.fn();
      readonly close = vi.fn();

      constructor(readonly url: string) {
        super();
        sockets.push(this);
      }
    }
    vi.stubGlobal("WebSocket", FakeWebSocket);
    vi.stubGlobal("window", {
      location: new URL("https://share.test/r/1234"),
      setTimeout,
      clearTimeout,
    });
    const statuses: string[] = [];
    const signal = new SignalingClient(
      {
        roomId: "1234",
        role: "viewer",
        clientId: "viewer-client",
      },
      {
        onMessage: () => undefined,
        onStatus: (status) => statuses.push(status),
        onTerminated: () => undefined,
        onAccessRequired: () => undefined,
      },
    );

    signal.start();
    sockets[0]!.dispatchEvent(new Event("open"));
    const closed = new Event("close");
    Object.defineProperty(closed, "code", { value: 1012 });
    sockets[0]!.dispatchEvent(closed);

    expect(statuses.at(-1)).toBe("reconnecting");
    signal.stop();
  });

  it("classifies a close-only authentication failure without claiming replacement", () => {
    const sockets: FakeWebSocket[] = [];
    class FakeWebSocket extends EventTarget {
      static readonly OPEN = 1;
      static readonly CLOSING = 2;
      readyState = FakeWebSocket.OPEN;
      readonly send = vi.fn();
      readonly close = vi.fn();

      constructor(readonly url: string) {
        super();
        sockets.push(this);
      }
    }
    vi.stubGlobal("WebSocket", FakeWebSocket);
    vi.stubGlobal("window", {
      location: new URL("https://share.test/r/1234"),
      setTimeout,
      clearTimeout,
    });
    const onTerminated = vi.fn();
    const signal = new SignalingClient(
      {
        roomId: "1234",
        role: "viewer",
        clientId: "viewer-client",
      },
      {
        onMessage: () => undefined,
        onStatus: () => undefined,
        onTerminated,
        onAccessRequired: () => undefined,
      },
    );

    signal.start();
    sockets[0]!.dispatchEvent(new Event("open"));
    const closed = new Event("close");
    Object.defineProperties(closed, {
      code: { value: 4003 },
      reason: { value: "Authentication required" },
    });
    sockets[0]!.dispatchEvent(closed);

    expect(onTerminated).toHaveBeenCalledOnce();
    expect(onTerminated).toHaveBeenCalledWith("SIGNAL_TERMINATED");
    expect(sockets).toHaveLength(1);
  });

  it("keeps a Host paused across reconnect until an explicit Resume is sent", () => {
    vi.useFakeTimers();
    const sockets: FakeWebSocket[] = [];
    class FakeWebSocket extends EventTarget {
      static readonly OPEN = 1;
      static readonly CLOSING = 2;
      readyState = FakeWebSocket.OPEN;
      readonly send = vi.fn();
      readonly close = vi.fn(() => {
        this.readyState = FakeWebSocket.CLOSING;
      });

      constructor(readonly url: string) {
        super();
        sockets.push(this);
      }
    }
    vi.stubGlobal("WebSocket", FakeWebSocket);
    vi.stubGlobal("window", {
      location: new URL("https://share.test/r/1234"),
      setTimeout: globalThis.setTimeout,
      clearTimeout: globalThis.clearTimeout,
    });
    const signal = new SignalingClient(
      {
        roomId: "1234",
        role: "host",
        token: "h".repeat(43),
        clientId: "host-client",
        routePolicy: DEFAULT_ROUTE_POLICY,
        shareGeneration: "share_generation_12345678",
        sharingPaused: true,
      },
      {
        onMessage: () => undefined,
        onStatus: () => undefined,
        onTerminated: () => undefined,
        onAccessRequired: () => undefined,
      },
    );
    const receive = (socket: FakeWebSocket, value: object) => {
      const event = new Event("message");
      Object.defineProperty(event, "data", { value: JSON.stringify(value) });
      socket.dispatchEvent(event);
    };
    const authenticate = (socket: FakeWebSocket) => {
      socket.dispatchEvent(new Event("open"));
      receive(socket, {
        type: "authenticated",
        protocol: SIGNALING_PROTOCOL,
        role: "host",
        peerId: "host_12345678",
        roomExpiresAt: null,
        maxViewers: 8,
        endpointMediaCopyCapacity: 2,
        hostOnline: true,
        hostPaused: true,
        connectionId: null,
        viewerPeerIds: [],
        iceConfig: { iceServers: [] },
        codeEntryPolicy: "open",
        viewerPasswordEnabled: false,
        viewerAuthorizationGeneration: "viewer_generation_12345678",
      });
    };
    const reconnect = (socket: FakeWebSocket) => {
      const close = new Event("close");
      Object.defineProperties(close, {
        code: { value: 1006 },
        reason: { value: "network interrupted" },
      });
      socket.dispatchEvent(close);
      vi.advanceTimersByTime(750);
    };

    signal.start();
    authenticate(sockets[0]!);
    reconnect(sockets[0]!);
    sockets[1]!.dispatchEvent(new Event("open"));
    expect(JSON.parse(String(sockets[1]!.send.mock.calls[0]![0]))).toMatchObject({
      type: "authenticate",
      sharingPaused: true,
    });
    receive(sockets[1]!, {
      type: "authenticated",
      protocol: SIGNALING_PROTOCOL,
      role: "host",
      peerId: "host_12345678",
      roomExpiresAt: null,
      maxViewers: 8,
      endpointMediaCopyCapacity: 2,
      hostOnline: true,
      hostPaused: true,
      connectionId: null,
      viewerPeerIds: [],
      iceConfig: { iceServers: [] },
      codeEntryPolicy: "open",
      viewerPasswordEnabled: false,
      viewerAuthorizationGeneration: "viewer_generation_12345678",
    });
    expect(signal.setSharingPaused(false)).toBe(true);
    expect(
      JSON.parse(String(sockets[1]!.send.mock.calls.at(-1)![0])),
    ).toMatchObject({
      type: "set-sharing-paused",
      shareGeneration: "share_generation_12345678",
      paused: false,
    });

    reconnect(sockets[1]!);
    sockets[2]!.dispatchEvent(new Event("open"));
    expect(JSON.parse(String(sockets[2]!.send.mock.calls[0]![0]))).toMatchObject({
      type: "authenticate",
      sharingPaused: false,
    });
    signal.stop();
  });

  it("replays the latest exact Host quality intent after reauthentication", () => {
    vi.useFakeTimers();
    const sockets: FakeWebSocket[] = [];
    class FakeWebSocket extends EventTarget {
      static readonly OPEN = 1;
      static readonly CLOSING = 2;
      readyState = FakeWebSocket.OPEN;
      readonly send = vi.fn();
      readonly close = vi.fn(() => {
        this.readyState = FakeWebSocket.CLOSING;
      });

      constructor(readonly url: string) {
        super();
        sockets.push(this);
      }
    }
    vi.stubGlobal("WebSocket", FakeWebSocket);
    vi.stubGlobal("window", {
      location: new URL("https://share.test/"),
      setTimeout: globalThis.setTimeout,
      clearTimeout: globalThis.clearTimeout,
    });
    const shareGeneration = "share_generation_12345678";
    const initialQuality = {
      resolution: "1080p",
      maxFramerate: 30,
      maxBitrate: 5_000_000,
      degradationPreference: "balanced",
      screenAudioQuality: "music",
    } as const;
    const firstPending = {
      ...initialQuality,
      resolution: "720p",
      maxBitrate: 3_000_000,
    } as const;
    const latestPending = {
      ...firstPending,
      maxFramerate: 60,
      maxBitrate: 8_000_000,
    } as const;
    let authenticatedCount = 0;
    let pendingDuringReauthentication: typeof latestPending | null = null;
    let signal!: SignalingClient;
    signal = new SignalingClient(
      {
        roomId: "1234",
        role: "host",
        token: "h".repeat(43),
        clientId: "host-client",
        routePolicy: DEFAULT_ROUTE_POLICY,
        shareGeneration,
        qualitySettings: initialQuality,
      },
      {
        onMessage: (message) => {
          if (message.type !== "authenticated") {
            return;
          }
          authenticatedCount += 1;
          if (authenticatedCount === 2) {
            pendingDuringReauthentication =
              signal.pendingHostQualitySettings(shareGeneration) as
                | typeof latestPending
                | null;
          }
        },
        onStatus: () => undefined,
        onTerminated: () => undefined,
        onAccessRequired: () => undefined,
      },
    );
    const receiveAuthenticated = (
      socket: FakeWebSocket,
      qualitySettings: QualitySettings = initialQuality,
    ) => {
      const event = new Event("message");
      Object.defineProperty(event, "data", {
        value: JSON.stringify({
          type: "authenticated",
          protocol: SIGNALING_PROTOCOL,
          role: "host",
          peerId: "host_12345678",
          roomExpiresAt: null,
          maxViewers: 8,
          endpointMediaCopyCapacity: 2,
          hostOnline: true,
          hostPaused: false,
          connectionId: null,
          viewerPeerIds: [],
          iceConfig: { iceServers: [] },
          codeEntryPolicy: "open",
          viewerPasswordEnabled: false,
          viewerAuthorizationGeneration: "viewer_generation_12345678",
          mediaMode: "peer-assisted",
          shareGeneration,
          routeRevision: 1,
          routeAssignment: {
            upstream: { kind: "none" },
            childPeerIds: [],
            sfuPublicationGeneration: null,
          },
          qualitySettings,
          routePolicy: DEFAULT_ROUTE_POLICY,
        }),
      });
      socket.dispatchEvent(event);
    };

    signal.start();
    sockets[0]!.dispatchEvent(new Event("open"));
    receiveAuthenticated(sockets[0]!);
    const close = new Event("close");
    Object.defineProperties(close, {
      code: { value: 1006 },
      reason: { value: "network interrupted" },
    });
    sockets[0]!.dispatchEvent(close);

    expect(signal.setHostQualitySettings(firstPending)).toBe(false);
    expect(signal.setHostQualitySettings(latestPending)).toBe(false);
    expect(
      signal.pendingHostQualitySettings("other_share_generation_12345678"),
    ).toBeNull();
    expect(signal.pendingHostQualitySettings(shareGeneration)).toEqual(
      latestPending,
    );

    vi.advanceTimersByTime(750);
    sockets[1]!.dispatchEvent(new Event("open"));
    expect(JSON.parse(String(sockets[1]!.send.mock.calls[0]![0]))).toMatchObject({
      type: "authenticate",
      shareGeneration,
      qualitySettings: latestPending,
    });
    receiveAuthenticated(sockets[1]!);

    expect(pendingDuringReauthentication).toEqual(latestPending);
    expect(sockets[1]!.send).toHaveBeenCalledTimes(2);
    expect(
      JSON.parse(String(sockets[1]!.send.mock.calls[1]![0])),
    ).toEqual({
      type: "set-quality-settings",
      qualitySettings: latestPending,
    });
    expect(signal.pendingHostQualitySettings(shareGeneration)).toEqual(
      latestPending,
    );

    receiveAuthenticated(sockets[1]!, latestPending);
    expect(sockets[1]!.send).toHaveBeenCalledTimes(2);
    expect(signal.pendingHostQualitySettings(shareGeneration)).toBeNull();
    signal.stop();
  });

  it("confirms an exact silent partition before replacing the socket immediately", () => {
    vi.useFakeTimers();
    let now = 0;
    const sockets: FakeWebSocket[] = [];
    class FakeWebSocket extends EventTarget {
      static readonly OPEN = 1;
      static readonly CLOSING = 2;
      readyState = FakeWebSocket.OPEN;
      readonly send = vi.fn();
      readonly close = vi.fn((code?: number, reason?: string) => {
        void code;
        void reason;
        this.readyState = FakeWebSocket.CLOSING;
      });

      constructor(readonly url: string) {
        super();
        sockets.push(this);
      }
    }
    vi.stubGlobal("WebSocket", FakeWebSocket);
    vi.stubGlobal("window", {
      location: new URL("https://share.test/r/1234"),
      setTimeout: globalThis.setTimeout,
      clearTimeout: globalThis.clearTimeout,
    });
    const statuses: string[] = [];
    const onMessage = vi.fn();
    const onTerminated = vi.fn();
    const signal = new SignalingClient(
      {
        roomId: "1234",
        role: "host",
        token: "h".repeat(43),
        clientId: "host-client",
        routePolicy: DEFAULT_ROUTE_POLICY,
      },
      {
        onMessage,
        onStatus: (status) => statuses.push(status),
        onTerminated,
        onAccessRequired: () => undefined,
      },
      () => now,
    );
    const receive = (socket: FakeWebSocket, value: object) => {
      const event = new Event("message");
      Object.defineProperty(event, "data", { value: JSON.stringify(value) });
      socket.dispatchEvent(event);
    };
    const authenticate = (socket: FakeWebSocket) => {
      socket.dispatchEvent(new Event("open"));
      receive(socket, {
        type: "authenticated",
        protocol: SIGNALING_PROTOCOL,
        role: "host",
        peerId: "host_12345678",
        roomExpiresAt: null,
        maxViewers: 8,
        endpointMediaCopyCapacity: 2,
        hostOnline: true,
        connectionId: null,
        viewerPeerIds: [],
        iceConfig: { iceServers: [] },
        codeEntryPolicy: "open",
        viewerPasswordEnabled: false,
        viewerAuthorizationGeneration: "viewer_generation_12345678",
      });
    };
    const advance = (milliseconds: number) => {
      now += milliseconds;
      vi.advanceTimersByTime(milliseconds);
    };

    signal.start();
    authenticate(sockets[0]!);
    advance(5_000);
    const first = JSON.parse(String(sockets[0]!.send.mock.calls.at(-1)![0]));
    expect(first).toEqual({ type: "signaling-challenge", sequence: 1 });

    advance(2_000);
    const confirm = JSON.parse(String(sockets[0]!.send.mock.calls.at(-1)![0]));
    expect(confirm).toEqual({ type: "signaling-challenge", sequence: 2 });
    receive(sockets[0]!, {
      type: "signaling-challenge-response",
      sequence: first.sequence,
    });
    advance(2_000);

    expect(sockets).toHaveLength(1);
    expect(sockets[0]!.close).not.toHaveBeenCalled();
    expect(statuses.at(-1)).toBe("connected");
    expect(onTerminated).not.toHaveBeenCalled();
    expect(
      sockets[0]!.send.mock.calls
        .map(([value]) => JSON.parse(String(value)).type)
        .includes("route-failed"),
    ).toBe(false);

    advance(3_000);
    const next = JSON.parse(String(sockets[0]!.send.mock.calls.at(-1)![0]));
    expect(next).toEqual({ type: "signaling-challenge", sequence: 3 });
    receive(sockets[0]!, {
      type: "signaling-challenge-response",
      sequence: next.sequence,
    });
    advance(2_000);

    expect(sockets).toHaveLength(1);
    expect(confirm.sequence).toBe(2);
    expect(onMessage).toHaveBeenCalledTimes(1);
    signal.stop();
  });

  it("rebases inactive, hidden, and obviously delayed challenge windows", () => {
    vi.useFakeTimers();
    let now = 0;
    let visibilityState: DocumentVisibilityState = "visible";
    const documentTarget = new EventTarget();
    Object.defineProperty(documentTarget, "visibilityState", {
      get: () => visibilityState,
    });
    const sockets: FakeWebSocket[] = [];
    class FakeWebSocket extends EventTarget {
      static readonly OPEN = 1;
      static readonly CLOSING = 2;
      readyState = FakeWebSocket.OPEN;
      readonly send = vi.fn();
      readonly close = vi.fn();

      constructor(readonly url: string) {
        super();
        sockets.push(this);
      }
    }
    vi.stubGlobal("WebSocket", FakeWebSocket);
    vi.stubGlobal("document", documentTarget);
    vi.stubGlobal("window", {
      location: new URL("https://share.test/r/1234"),
      setTimeout: globalThis.setTimeout,
      clearTimeout: globalThis.clearTimeout,
    });
    const onMessage = vi.fn();
    const signal = new SignalingClient(
      {
        roomId: "1234",
        role: "viewer",
        clientId: "viewer-client",
      },
      {
        onMessage,
        onStatus: () => undefined,
        onTerminated: () => undefined,
        onAccessRequired: () => undefined,
      },
      () => now,
    );
    const receive = (value: object) => {
      const event = new Event("message");
      Object.defineProperty(event, "data", { value: JSON.stringify(value) });
      sockets[0]!.dispatchEvent(event);
    };
    const advance = (milliseconds: number) => {
      now += milliseconds;
      vi.advanceTimersByTime(milliseconds);
    };

    signal.start();
    sockets[0]!.dispatchEvent(new Event("open"));
    receive({
      type: "authenticated",
      protocol: SIGNALING_PROTOCOL,
      role: "viewer",
      peerId: "viewer_12345678",
      roomExpiresAt: null,
      maxViewers: 8,
      endpointMediaCopyCapacity: 2,
      hostOnline: true,
      connectionId: "connection_12345678",
      viewerPeerIds: [],
      iceConfig: { iceServers: [] },
      codeEntryPolicy: "open",
      viewerAuthorizationGeneration: "viewer_generation_12345678",
      mediaMode: "peer-assisted",
      shareGeneration: "share_generation_12345678",
      routeRevision: 1,
      routeAssignment: {
        upstream: { kind: "none" },
        childPeerIds: [],
        sfuPublicationGeneration: null,
      },
      qualitySettings: {
        resolution: "1080p",
        maxFramerate: 30,
        maxBitrate: 5_000_000,
        degradationPreference: "balanced",
        screenAudioQuality: "music",
      },
      routePolicy: DEFAULT_ROUTE_POLICY,
    });
    advance(5_000);
    expect(sockets[0]!.send).toHaveBeenCalledTimes(2);
    const waiting = JSON.parse(String(sockets[0]!.send.mock.calls.at(-1)![0]));
    expect(waiting.type).toBe("signaling-challenge");
    receive({
      type: "signaling-challenge-response",
      sequence: waiting.sequence,
    });

    receive({
      type: "route-update",
      revision: 2,
      phase: "active",
      assignment: {
        upstream: { kind: "peer", peerId: "host_12345678" },
        childPeerIds: [],
        sfuPublicationGeneration: null,
      },
    });
    advance(5_000);
    const first = JSON.parse(String(sockets[0]!.send.mock.calls.at(-1)![0]));
    expect(first.type).toBe("signaling-challenge");

    visibilityState = "hidden";
    documentTarget.dispatchEvent(new Event("visibilitychange"));
    advance(20_000);
    expect(sockets).toHaveLength(1);
    expect(sockets[0]!.send).toHaveBeenCalledTimes(3);

    visibilityState = "visible";
    documentTarget.dispatchEvent(new Event("visibilitychange"));
    advance(5_000);
    const visible = JSON.parse(String(sockets[0]!.send.mock.calls.at(-1)![0]));
    receive({
      type: "signaling-challenge-response",
      sequence: visible.sequence,
    });
    now += 7_000;
    vi.advanceTimersByTime(5_000);
    expect(sockets[0]!.send).toHaveBeenCalledTimes(4);
    advance(5_000);
    expect(sockets[0]!.send).toHaveBeenCalledTimes(5);
    expect(onMessage).toHaveBeenCalledTimes(2);
    signal.stop();
  });

  it.each([
    JSON.stringify({
      type: "error",
      code: "INVALID_MESSAGE",
      message: "Message is invalid",
    }),
    JSON.stringify({
      type: "authenticated",
      role: "viewer",
      peerId: "viewer_12345678",
      roomExpiresAt: null,
      maxViewers: 8,
      hostOnline: true,
      connectionId: null,
      viewerPeerIds: [],
      iceConfig: { iceServers: [] },
    }),
  ])(
    "terminates once when a server payload is incompatible with the current wire",
    (payload) => {
      const sockets: FakeWebSocket[] = [];
      class FakeWebSocket extends EventTarget {
        static readonly CLOSING = 2;
        readyState = 1;
        readonly send = vi.fn();
        readonly close = vi.fn();

        constructor(readonly url: string) {
          super();
          sockets.push(this);
        }
      }
      vi.stubGlobal("WebSocket", FakeWebSocket);
      vi.stubGlobal("window", {
        location: new URL("https://share.test/r/1234"),
        setTimeout,
        clearTimeout,
      });
      const onTerminated = vi.fn();
      const signal = new SignalingClient(
        {
          roomId: "1234",
          role: "viewer",
          clientId: "viewer-client",
        },
        {
          onMessage: () => undefined,
          onStatus: () => undefined,
          onTerminated,
          onAccessRequired: () => undefined,
        },
      );

      signal.start();
      sockets[0]!.dispatchEvent(new Event("open"));
      expect(
        JSON.parse(String(sockets[0]!.send.mock.calls[0]![0])),
      ).toMatchObject({
        type: "authenticate",
        protocol: SIGNALING_PROTOCOL,
      });
      const message = new Event("message");
      Object.defineProperty(message, "data", { value: payload });
      sockets[0]!.dispatchEvent(message);
      const close = new Event("close");
      Object.defineProperties(close, {
        code: { value: 1008 },
        reason: { value: "Invalid message" },
      });
      sockets[0]!.dispatchEvent(close);

      expect(onTerminated).toHaveBeenCalledOnce();
      expect(onTerminated).toHaveBeenCalledWith("STALE_CLIENT");
      expect(sockets[0]!.close).toHaveBeenCalledOnce();
      expect(sockets).toHaveLength(1);
    },
  );

  it("returns only a Host to the admission gate after AUTH_REQUIRED", () => {
    const sockets: FakeWebSocket[] = [];
    class FakeWebSocket extends EventTarget {
      static readonly CLOSING = 2;
      readyState = 1;
      readonly send = vi.fn();
      readonly close = vi.fn();

      constructor(readonly url: string) {
        super();
        sockets.push(this);
      }
    }
    vi.stubGlobal("WebSocket", FakeWebSocket);
    vi.stubGlobal("window", {
      location: new URL("https://share.test/r/1234"),
      setTimeout,
      clearTimeout,
    });
    const onAccessRequired = vi.fn();
    const statuses: string[] = [];
    const onMessage = vi.fn();
    const signal = new SignalingClient(
      {
        roomId: "1234",
        role: "host",
        token: "h".repeat(43),
        clientId: "host-client",
        routePolicy: DEFAULT_ROUTE_POLICY,
      },
      {
        onMessage,
        onStatus: (status) => statuses.push(status),
        onTerminated: () => undefined,
        onAccessRequired,
      },
    );

    signal.start();
    sockets[0]!.dispatchEvent(new Event("open"));
    const message = new Event("message");
    Object.defineProperties(message, {
      data: {
        value: JSON.stringify({
          type: "error",
          code: "AUTH_REQUIRED",
          message: "Site access is required",
        }),
      },
    });
    sockets[0]!.dispatchEvent(message);

    expect(onAccessRequired).toHaveBeenCalledOnce();
    expect(onMessage).toHaveBeenCalledWith({
      type: "error",
      code: "AUTH_REQUIRED",
      message: "Site access is required",
    });
    expect(statuses.at(-1)).toBe("offline");
    expect(sockets).toHaveLength(1);
  });
});

describe("WebRTC stats parsing", () => {
  it("sums sender layers and rebases incomplete bitrate windows", () => {
    const accumulator = createNativeSenderQualityAccumulator();
    const sample = (
      timestamp: number,
      bytesByLayer: Readonly<Record<string, number>>,
    ): number | null => {
      const records: Array<[string, Record<string, unknown>]> = [
        [
          "source",
          {
            id: "source",
            type: "media-source",
            timestamp,
            trackIdentifier: "track",
          },
        ],
      ];
      for (const [id, bytesSent] of Object.entries(bytesByLayer)) {
        records.push([
          id,
          {
            id,
            type: "outbound-rtp",
            kind: "video",
            timestamp,
            mediaSourceId: "source",
            bytesSent,
            framesEncoded: timestamp / 20,
            qualityLimitationReason: "none",
            qualityLimitationDurations: {
              none: timestamp / 1_000,
              bandwidth: 0,
              cpu: 0,
              other: 0,
            },
          },
        ]);
      }
      return collectNativeSenderQualityFromReport(
        new Map(records) as unknown as RTCStatsReport,
        "track",
        accumulator,
      ).bitrateKbps;
    };

    expect(sample(1_000, { low: 10_000, high: 20_000 })).toBeNull();
    expect(sample(3_000, { low: 110_000, high: 220_000 })).toBe(1_200);
    expect(
      sample(5_000, { low: 210_000, high: 420_000, mid: 50_000 }),
    ).toBeNull();
    expect(
      sample(7_000, { low: 310_000, high: 620_000, mid: 150_000 }),
    ).toBe(1_600);
    expect(
      sample(9_000, { low: 10_000, high: 820_000, mid: 250_000 }),
    ).toBeNull();
    expect(
      sample(11_000, {
        low: 110_000,
        high: 1_020_000,
        mid: 350_000,
      }),
    ).toBe(1_600);
  });

  it("binds media, remote evidence, transport, and pair without guessing", async () => {
    const entry = (
      id: string,
      type: string,
      values: Record<string, unknown>,
    ): [string, Record<string, unknown>] => [
      id,
      { id, type, timestamp: 2_000, ...values },
    ];
    const report = new Map<string, Record<string, unknown>>([
      entry("transport-a", "transport", {
        selectedCandidatePairId: "pair-a",
      }),
      entry("transport-z", "transport", {
        selectedCandidatePairId: "pair-z",
      }),
      entry("pair-a", "candidate-pair", {
        transportId: "transport-a",
        localCandidateId: "local-a",
        remoteCandidateId: "remote-candidate-a",
        currentRoundTripTime: 0.02,
      }),
      entry("pair-z", "candidate-pair", {
        transportId: "transport-z",
        localCandidateId: "local-z",
        remoteCandidateId: "remote-candidate-z",
      }),
      entry("local-a", "local-candidate", {
        candidateType: "host",
        protocol: "udp",
        address: "192.0.2.10",
        port: 50_000,
      }),
      entry("remote-candidate-a", "remote-candidate", {
        candidateType: "srflx",
        protocol: "udp",
        address: "2001:db8::10",
        port: 50_001,
      }),
      entry("local-z", "local-candidate", {
        candidateType: "relay",
        protocol: "tcp",
      }),
      entry("remote-candidate-z", "remote-candidate", {
        candidateType: "relay",
        protocol: "tcp",
      }),
      entry("outbound-a", "outbound-rtp", {
        kind: "video",
        ssrc: 111,
        mid: "0",
        transportId: "transport-a",
        mediaSourceId: "source-a",
        remoteId: "remote-inbound-a",
        codecId: "codec-a",
        rid: "main",
        scalabilityMode: "L2T3_KEY",
        bytesSent: 2_000,
        framesEncoded: 60,
        totalEncodeTime: 0.3,
        encoderImplementation: "ExternalEncoder",
        powerEfficientEncoder: true,
      }),
      entry("outbound-z", "outbound-rtp", {
        kind: "video",
        ssrc: 999,
        transportId: "transport-z",
        mediaSourceId: "source-z",
        remoteId: "remote-inbound-z",
        codecId: "codec-z",
        bytesSent: 99_000,
        framesEncoded: 99,
      }),
      entry("source-a", "media-source", {
        kind: "video",
        trackIdentifier: "capture-track-a",
        framesPerSecond: 58.5,
      }),
      entry("source-z", "media-source", {
        kind: "video",
        trackIdentifier: "capture-track-z",
      }),
      entry("remote-inbound-a", "remote-inbound-rtp", {
        kind: "video",
        packetsLost: 2,
        jitter: 0.004,
      }),
      entry("remote-inbound-z", "remote-inbound-rtp", {
        kind: "video",
        packetsLost: 999,
        jitter: 0.9,
      }),
      entry("codec-a", "codec", {
        transportId: "transport-a",
        mimeType: "video/H264",
        sdpFmtpLine:
          "profile-level-id=42E01F; packetization-mode=1; " +
          "level-asymmetry-allowed=1; sprop-parameter-sets=do-not-expose; " +
          "x-google-start-bitrate=99999",
      }),
      entry("codec-z", "codec", {
        transportId: "transport-z",
        mimeType: "video/VP9",
        sdpFmtpLine: "profile-id=3; max-fr=15; max-fs=1200",
      }),
    ]);
    const connection = {
      getStats: async () => report as unknown as RTCStatsReport,
    } as unknown as RTCPeerConnection;

    const accumulator = createStatsAccumulator();
    const metrics = await collectConnectionMetrics(
      connection,
      "send",
      accumulator,
      { trackIdentifier: "capture-track-a" },
    );

    expect(metrics).toMatchObject({
      sampleTimestampMs: 2_000,
      sampleWindowMs: null,
      rtpStatsId: "outbound-a",
      rtpSsrc: 111,
      rtpMid: "0",
      rtpRid: "main",
      trackIdentifier: "capture-track-a",
      mediaSourceFramesPerSecond: 58.5,
      selectedCandidatePairId: "pair-a",
      path: "direct",
      iceProtocol: "udp",
      localCandidateAddress: "192.0.2.10",
      localCandidatePort: 50_000,
      remoteCandidateAddress: "2001:db8::10",
      remoteCandidatePort: 50_001,
      packetsLost: 2,
      jitterMs: 4,
      rttMs: 20,
      codec: "video/H264",
      codecProfile: "profile-level-id=42e01f",
      codecParameters:
        "packetization-mode=1; level-asymmetry-allowed=1",
      scalabilityMode: "L2T3_KEY",
      encoderImplementation: "ExternalEncoder",
      powerEfficientEncoder: true,
      intervalFramesEncoded: null,
      intervalEncodeTimeMs: null,
    });
    expect(JSON.stringify(metrics)).not.toContain("sprop-parameter-sets");
    expect(JSON.stringify(metrics)).not.toContain("x-google-start-bitrate");

    report.get("remote-candidate-a")!.address = null;
    delete report.get("remote-candidate-a")!.port;
    expect(
      await collectConnectionMetrics(connection, "send", accumulator, {
        trackIdentifier: "capture-track-a",
      }),
    ).toMatchObject({
      selectedCandidatePairId: "pair-a",
      localCandidateAddress: "192.0.2.10",
      localCandidatePort: 50_000,
      remoteCandidateAddress: null,
      remoteCandidatePort: null,
    });
    report.get("remote-candidate-a")!.address = "2001:db8::10";
    report.get("remote-candidate-a")!.port = 50_001;

    report.get("transport-a")!.selectedCandidatePairId = "pair-z";
    const wrongTransportPair = await collectConnectionMetrics(
      connection,
      "send",
      accumulator,
      { trackIdentifier: "capture-track-a" },
    );
    expect(wrongTransportPair).toMatchObject({
      rtpStatsId: "outbound-a",
      selectedCandidatePairId: null,
      path: "unknown",
    });

    report.get("transport-a")!.selectedCandidatePairId = "pair-a";
    report.get("codec-a")!.transportId = "transport-z";
    const wrongTransportCodec = await collectConnectionMetrics(
      connection,
      "send",
      accumulator,
      { trackIdentifier: "capture-track-a" },
    );
    expect(wrongTransportCodec).toMatchObject({
      rtpStatsId: "outbound-a",
      codec: null,
      codecProfile: null,
      codecParameters: null,
    });
    report.get("codec-a")!.transportId = "transport-a";

    report.get("local-a")!.type = "remote-candidate";
    report.get("remote-candidate-a")!.type = "local-candidate";
    const malformedCandidateReferences = await collectConnectionMetrics(
      connection,
      "send",
      accumulator,
      { trackIdentifier: "capture-track-a" },
    );
    expect(malformedCandidateReferences).toMatchObject({
      selectedCandidatePairId: null,
      path: "unknown",
      localCandidateType: null,
      remoteCandidateType: null,
    });
    report.get("local-a")!.type = "local-candidate";
    report.get("remote-candidate-a")!.type = "remote-candidate";

    delete report.get("outbound-a")!.transportId;
    const unboundTransport = await collectConnectionMetrics(
      connection,
      "send",
      accumulator,
      { trackIdentifier: "capture-track-a" },
    );
    expect(unboundTransport).toMatchObject({
      rtpStatsId: "outbound-a",
      selectedCandidatePairId: null,
      path: "unknown",
      codec: null,
      codecProfile: null,
      codecParameters: null,
    });
    report.get("outbound-a")!.transportId = "transport-a";

    report.set("outbound-a-layer-2", {
      id: "outbound-a-layer-2",
      type: "outbound-rtp",
      timestamp: 3_000,
      kind: "video",
      ssrc: 112,
      transportId: "transport-a",
      mediaSourceId: "source-a",
      bytesSent: 3_000,
      framesEncoded: 90,
    });
    const ambiguous = await collectConnectionMetrics(
      connection,
      "send",
      accumulator,
      { trackIdentifier: "capture-track-a" },
    );
    expect(ambiguous).toMatchObject({
      rtpStatsId: null,
      selectedCandidatePairId: null,
      packetsLost: null,
      codec: null,
      codecProfile: null,
      codecParameters: null,
      scalabilityMode: null,
    });
  });

  it.each([
    {
      mimeType: "video/VP8",
      fmtp: "max-fr=60; max-fs=3600",
      profile: null,
      parameters: "max-fr=60; max-fs=3600",
    },
    {
      mimeType: "video/VP9",
      fmtp: "profile-id=2; max-fr=60; max-fs=3600",
      profile: "profile-id=2",
      parameters: "max-fr=60; max-fs=3600",
    },
    {
      mimeType: "video/AV1",
      fmtp: "profile=1; level-idx=8; tier=0",
      profile: "profile=1",
      parameters: "level-idx=8; tier=0",
    },
    {
      mimeType: "video/H264",
      fmtp:
        "profile-level-id=42e01f; profile-level-id=invalid; " +
        "packetization-mode=1",
      profile: null,
      parameters: "packetization-mode=1",
    },
    {
      mimeType: "video/H264",
      fmtp: `profile-level-id=42e01f; ignored=${"x".repeat(2_048)}`,
      profile: null,
      parameters: null,
    },
    {
      mimeType: "video/H264",
      fmtp: [
        "profile-level-id=42e01f",
        ...Array.from({ length: 32 }, (_, index) => `ignored-${index}=1`),
      ].join(";"),
      profile: null,
      parameters: null,
    },
    {
      mimeType: "video/H265",
      fmtp: "profile-id=1; tier-flag=0; level-id=93",
      profile: null,
      parameters: null,
    },
  ])(
    "derives only allowlisted $mimeType format parameters",
    async ({ mimeType, fmtp, profile, parameters }) => {
      const report = new Map<string, unknown>([
        [
          "transport",
          { id: "transport", type: "transport", timestamp: 1_000 },
        ],
        [
          "outbound",
          {
            id: "outbound",
            type: "outbound-rtp",
            timestamp: 1_000,
            kind: "video",
            ssrc: 101,
            transportId: "transport",
            codecId: "codec",
            bytesSent: 1_000,
            framesEncoded: 30,
          },
        ],
        [
          "codec",
          {
            id: "codec",
            type: "codec",
            timestamp: 1_000,
            transportId: "transport",
            mimeType,
            sdpFmtpLine: fmtp,
          },
        ],
      ]) as unknown as RTCStatsReport;
      const connection = {
        getStats: async () => report,
      } as unknown as RTCPeerConnection;

      const metrics = await collectConnectionMetrics(
        connection,
        "send",
        createStatsAccumulator(),
      );
      expect(metrics).toMatchObject({
        codec: mimeType,
        codecProfile: profile,
        codecParameters: parameters,
        scalabilityMode: null,
      });
      expect(
        qualityEvidenceWindowFromMetrics({
          ...metrics,
          sampleWindowMs: 2_000,
        })?.metrics,
      ).toMatchObject({
        codec: mimeType,
        codecProfile: profile,
        codecParameters: parameters,
      });
    },
  );

  it("rebases sender retransmission deltas after counter rollback", async () => {
    const outbound = (
      timestamp: number,
      retransmittedPacketsSent: number,
      retransmittedBytesSent: number,
      packetsSent: number,
      packetsLost: number,
    ) =>
      new Map<string, unknown>([
        [
          "outbound",
          {
            id: "outbound",
            type: "outbound-rtp",
            timestamp,
            kind: "video",
            ssrc: 101,
            remoteId: "remote-inbound",
            bytesSent: timestamp * 10,
            framesEncoded: timestamp / 10,
            packetsSent,
            retransmittedPacketsSent,
            retransmittedBytesSent,
          },
        ],
        [
          "remote-inbound",
          {
            id: "remote-inbound",
            type: "remote-inbound-rtp",
            timestamp,
            kind: "video",
            packetsLost,
          },
        ],
      ]) as unknown as RTCStatsReport;
    const reports = [
      outbound(1_000, 2, 200, 100, 1),
      outbound(2_000, 5, 800, 400, 3),
      outbound(3_000, 1, 100, 50, 1),
      outbound(4_000, 4, 700, 350, 4),
    ];
    const connection = {
      getStats: async () => reports.shift()!,
    } as unknown as RTCPeerConnection;
    const accumulator = createStatsAccumulator();
    const sample = () =>
      collectConnectionMetrics(connection, "send", accumulator);
    const first = await sample();
    const stable = await sample();
    const reset = await sample();
    const afterReset = await sample();

    expect(first.intervalRetransmittedPackets).toBeNull();
    expect(stable).toMatchObject({
      intervalPacketsSent: 300,
      intervalPacketsLost: 2,
      intervalRetransmittedPackets: 3,
      intervalRetransmittedBytes: 600,
    });
    expect(reset).toMatchObject({
      intervalPacketsSent: null,
      intervalPacketsLost: null,
      intervalRetransmittedPackets: null,
      intervalRetransmittedBytes: null,
    });
    expect(afterReset).toMatchObject({
      intervalPacketsSent: 300,
      intervalPacketsLost: 3,
      intervalRetransmittedPackets: 3,
      intervalRetransmittedBytes: 600,
    });
  });

  it("keeps an out-of-contract relay candidate unclassified", async () => {
    const report = new Map<string, Record<string, unknown>>([
      [
        "transport",
        {
          id: "transport",
          type: "transport",
          timestamp: 2_000,
          selectedCandidatePairId: "pair",
        },
      ],
      [
        "pair",
        {
          id: "pair",
          type: "candidate-pair",
          timestamp: 2_000,
          transportId: "transport",
          state: "succeeded",
          nominated: true,
          localCandidateId: "local",
          remoteCandidateId: "remote",
        },
      ],
      [
        "local",
        {
          id: "local",
          type: "local-candidate",
          timestamp: 2_000,
          candidateType: "relay",
          protocol: "udp",
        },
      ],
      [
        "remote",
        {
          id: "remote",
          type: "remote-candidate",
          timestamp: 2_000,
          candidateType: "host",
          protocol: "udp",
        },
      ],
      [
        "inbound",
        {
          id: "inbound",
          type: "inbound-rtp",
          timestamp: 2_000,
          kind: "video",
          transportId: "transport",
          bytesReceived: 2_000,
          framesDecoded: 100,
          totalDecodeTime: 0.5,
        },
      ],
    ]);
    const secondReport = new Map(report);
    secondReport.set("inbound", {
      id: "inbound",
      type: "inbound-rtp",
      timestamp: 4_000,
      kind: "video",
      transportId: "transport",
      bytesReceived: 4_000,
      framesDecoded: 150,
      totalDecodeTime: 1.5,
    });
    const reports = [report, secondReport];
    const connection = {
      getStats: async () =>
        reports.shift() as unknown as RTCStatsReport,
    } as unknown as RTCPeerConnection;
    const accumulator = createStatsAccumulator();

    const firstMetrics = await collectConnectionMetrics(
      connection,
      "receive",
      accumulator,
    );
    const metrics = await collectConnectionMetrics(
      connection,
      "receive",
      accumulator,
    );

    expect(firstMetrics.intervalDecodeMs).toBeNull();
    expect(metrics).toMatchObject({
      path: "unknown",
      iceProtocol: "udp",
      localCandidateType: "relay",
      remoteCandidateType: "host",
      intervalDecodeMs: 20,
    });
  });

  it("rebases interval metrics when the RTP stream or its counters reset", async () => {
    const inbound = (
      id: string,
      timestamp: number,
      bytesReceived: number,
      framesDecoded: number,
      totalDecodeTime: number,
    ) =>
      new Map<string, unknown>([
        [
          id,
          {
            id,
            type: "inbound-rtp",
            timestamp,
            kind: "video",
            bytesReceived,
            framesDecoded,
            totalDecodeTime,
          },
        ],
      ]) as unknown as RTCStatsReport;
    const reports = [
      inbound("inbound-a", 1_000, 10_000, 100, 0.5),
      inbound("inbound-b", 2_000, 20_000, 150, 1.5),
      inbound("inbound-b", 3_000, 22_000, 160, 1.7),
      inbound("inbound-b", 4_000, 1_000, 10, 0.1),
      inbound("inbound-b", 5_000, 3_000, 20, 0.3),
    ];
    const connection = {
      getStats: async () => reports.shift()!,
    } as unknown as RTCPeerConnection;
    const accumulator = createStatsAccumulator();

    await collectConnectionMetrics(connection, "receive", accumulator);
    const streamChanged = await collectConnectionMetrics(
      connection,
      "receive",
      accumulator,
    );
    const afterStreamChange = await collectConnectionMetrics(
      connection,
      "receive",
      accumulator,
    );
    const countersReset = await collectConnectionMetrics(
      connection,
      "receive",
      accumulator,
    );
    const afterCounterReset = await collectConnectionMetrics(
      connection,
      "receive",
      accumulator,
    );

    expect(streamChanged).toMatchObject({
      bitrateKbps: null,
      framesPerSecond: null,
      intervalDecodeMs: null,
    });
    expect(afterStreamChange).toMatchObject({
      bitrateKbps: 16,
      framesPerSecond: 10,
    });
    expect(afterStreamChange.intervalDecodeMs).toBeCloseTo(20);
    expect(countersReset).toMatchObject({
      bitrateKbps: null,
      framesPerSecond: null,
      intervalDecodeMs: null,
    });
    expect(afterCounterReset).toMatchObject({
      bitrateKbps: 16,
      framesPerSecond: 10,
    });
    expect(afterCounterReset.intervalDecodeMs).toBeCloseTo(20);
  });

  it("rebases receiver event deltas on SSRC changes and counter resets", async () => {
    const inbound = (
      timestamp: number,
      ssrc: number,
      framesDropped: number,
      freezeCount: number,
      totalFreezesDuration: number,
      pauseCount: number,
      totalPausesDuration: number,
      retransmittedPacketsReceived: number,
      retransmittedBytesReceived: number,
    ) =>
      new Map<string, unknown>([
        [
          "inbound",
          {
            id: "inbound",
            type: "inbound-rtp",
            timestamp,
            kind: "video",
            ssrc,
            bytesReceived: timestamp * 10,
            framesDecoded: timestamp / 10,
            framesDropped,
            freezeCount,
            totalFreezesDuration,
            pauseCount,
            totalPausesDuration,
            retransmittedPacketsReceived,
            retransmittedBytesReceived,
          },
        ],
      ]) as unknown as RTCStatsReport;
    const reports = [
      inbound(1_000, 101, 2, 1, 0.25, 0, 0, 3, 300),
      inbound(2_000, 101, 5, 2, 2.75, 1, 5.5, 7, 900),
      inbound(3_000, 202, 20, 8, 4, 3, 16, 30, 4_000),
      inbound(4_000, 202, 22, 9, 6.25, 4, 21.5, 33, 4_600),
      inbound(5_000, 202, 1, 0, 0.25, 0, 0.25, 2, 200),
      inbound(6_000, 202, 4, 1, 2.5, 1, 6.25, 6, 1_000),
    ];
    const connection = {
      getStats: async () => reports.shift()!,
    } as unknown as RTCPeerConnection;
    const accumulator = createStatsAccumulator();
    const sample = () =>
      collectConnectionMetrics(connection, "receive", accumulator);
    const first = await sample();
    const stable = await sample();
    const changedSsrc = await sample();
    const afterSsrcChange = await sample();
    const reset = await sample();
    const afterReset = await sample();

    expect(first).toMatchObject({
      sampleWindowMs: null,
      intervalFramesDropped: null,
      intervalFreezeCount: null,
      intervalFreezeDurationMs: null,
      intervalPauseCount: null,
      intervalPauseDurationMs: null,
      intervalRetransmittedPackets: null,
      intervalRetransmittedBytes: null,
    });
    expect(stable).toMatchObject({
      sampleWindowMs: 1_000,
      intervalFramesDropped: 3,
      intervalFreezeCount: 1,
      intervalFreezeDurationMs: 2_500,
      intervalPauseCount: 1,
      intervalPauseDurationMs: 5_500,
      intervalRetransmittedPackets: 4,
      intervalRetransmittedBytes: 600,
    });
    expect(changedSsrc).toMatchObject({
      rtpSsrc: 202,
      sampleWindowMs: null,
      intervalFramesDropped: null,
      intervalFreezeCount: null,
      intervalFreezeDurationMs: null,
      intervalPauseCount: null,
      intervalPauseDurationMs: null,
      intervalRetransmittedPackets: null,
      intervalRetransmittedBytes: null,
    });
    expect(afterSsrcChange).toMatchObject({
      sampleWindowMs: 1_000,
      intervalFramesDropped: 2,
      intervalFreezeCount: 1,
      intervalFreezeDurationMs: 2_250,
      intervalPauseCount: 1,
      intervalPauseDurationMs: 5_500,
      intervalRetransmittedPackets: 3,
      intervalRetransmittedBytes: 600,
    });
    expect(reset).toMatchObject({
      sampleWindowMs: 1_000,
      intervalFramesDropped: null,
      intervalFreezeCount: null,
      intervalFreezeDurationMs: null,
      intervalPauseCount: null,
      intervalPauseDurationMs: null,
      intervalRetransmittedPackets: null,
      intervalRetransmittedBytes: null,
    });
    expect(afterReset).toMatchObject({
      sampleWindowMs: 1_000,
      intervalFramesDropped: 3,
      intervalFreezeCount: 1,
      intervalFreezeDurationMs: 2_250,
      intervalPauseCount: 1,
      intervalPauseDurationMs: 6_000,
      intervalRetransmittedPackets: 4,
      intervalRetransmittedBytes: 800,
    });
  });

  it("keeps unavailable pause counters unknown and receive-only", async () => {
    const report = (
      type: "inbound-rtp" | "outbound-rtp",
      timestamp: number,
    ) =>
      new Map<string, unknown>([
        [
          "video",
          {
            id: "video",
            type,
            timestamp,
            kind: "video",
            ssrc: 101,
            ...(type === "inbound-rtp"
              ? { bytesReceived: timestamp, framesDecoded: timestamp / 100 }
              : {
                  bytesSent: timestamp,
                  framesEncoded: timestamp / 100,
                  pauseCount: timestamp / 1_000,
                  totalPausesDuration: timestamp / 1_000,
                }),
          },
        ],
      ]) as unknown as RTCStatsReport;

    const receiveAccumulator = createStatsAccumulator();
    collectConnectionMetricsFromReport(
      report("inbound-rtp", 1_000),
      "receive",
      receiveAccumulator,
    );
    const receive = collectConnectionMetricsFromReport(
      report("inbound-rtp", 2_000),
      "receive",
      receiveAccumulator,
    );
    expect(receive).toMatchObject({
      intervalPauseCount: null,
      intervalPauseDurationMs: null,
    });

    const sendAccumulator = createStatsAccumulator();
    collectConnectionMetricsFromReport(
      report("outbound-rtp", 1_000),
      "send",
      sendAccumulator,
    );
    const send = collectConnectionMetricsFromReport(
      report("outbound-rtp", 2_000),
      "send",
      sendAccumulator,
    );
    expect(send).toMatchObject({
      intervalPauseCount: null,
      intervalPauseDurationMs: null,
    });
  });

  it("derives a bounded inbound C window from adjacent RTP counters", async () => {
    const inbound = (
      timestamp: number,
      packetsReceived: number,
      packetsLost: number,
      framesDecoded: number,
      totalDecodeTime: number,
    ) =>
      new Map<string, unknown>([
        [
          "transport",
          { id: "transport", type: "transport", timestamp },
        ],
        [
          "codec",
          {
            id: "codec",
            type: "codec",
            timestamp,
            transportId: "transport",
            mimeType: "video/H264",
            sdpFmtpLine:
              "profile-level-id=42e01f; packetization-mode=1; " +
              "sprop-parameter-sets=must-not-leave-stats",
          },
        ],
        [
          "inbound",
          {
            id: "inbound",
            type: "inbound-rtp",
            timestamp,
            kind: "video",
            ssrc: 101,
            transportId: "transport",
            codecId: "codec",
            bytesReceived: timestamp * 10,
            packetsReceived,
            packetsLost,
            framesDecoded,
            framesDropped: 3,
            freezeCount: 1,
            totalFreezesDuration: 0.25,
            totalDecodeTime,
            frameWidth: 1_920,
            frameHeight: 1_080,
            scalabilityMode: "L3T3_KEY",
          },
        ],
      ]) as unknown as RTCStatsReport;
    const reports = [
      inbound(1_000, 1_000, 10, 60, 0.12),
      inbound(3_000, 2_500, 12, 180, 0.42),
      inbound(5_000, 4_000, 11, 300, 0.72),
    ];
    const connection = {
      getStats: async () => reports.shift()!,
    } as unknown as RTCPeerConnection;
    const accumulator = createStatsAccumulator();

    await collectConnectionMetrics(connection, "receive", accumulator);
    const stable = await collectConnectionMetrics(
      connection,
      "receive",
      accumulator,
    );
    const correctedLoss = await collectConnectionMetrics(
      connection,
      "receive",
      accumulator,
    );

    expect(stable).toMatchObject({
      sampleWindowMs: 2_000,
      frameWidth: 1_920,
      frameHeight: 1_080,
      intervalPacketsReceived: 1_500,
      intervalPacketsLost: 2,
      packetLossPercent: (2 / 1_502) * 100,
      intervalFramesDecoded: 120,
      intervalDecodeMs: 2.5,
      codec: "video/H264",
      codecProfile: "profile-level-id=42e01f",
      codecParameters: "packetization-mode=1",
      scalabilityMode: null,
    });
    expect(JSON.stringify(stable)).not.toContain("sprop-parameter-sets");
    expect(correctedLoss).toMatchObject({
      intervalPacketsLost: null,
      packetLossPercent: null,
    });
  });

  it("reports verified inbound audio codec and interval transport facts", async () => {
    const report = (
      timestamp: number,
      videoPacketsReceived: number,
      videoPacketsLost: number,
      audioBytesReceived: number,
      audioPacketsReceived: number,
      audioPacketsLost: number,
      audioCodecTransportId = "transport",
    ) =>
      new Map<string, unknown>([
        [
          "transport",
          { id: "transport", type: "transport", timestamp },
        ],
        [
          "video-codec",
          {
            id: "video-codec",
            type: "codec",
            timestamp,
            transportId: "transport",
            mimeType: "video/VP8",
          },
        ],
        [
          "audio-codec",
          {
            id: "audio-codec",
            type: "codec",
            timestamp,
            transportId: audioCodecTransportId,
            mimeType: "audio/opus",
            clockRate: 48_000,
            channels: 2,
            sdpFmtpLine: "minptime=10;useinbandfec=1",
          },
        ],
        [
          "video-inbound",
          {
            id: "video-inbound",
            type: "inbound-rtp",
            timestamp,
            kind: "video",
            ssrc: 101,
            transportId: "transport",
            codecId: "video-codec",
            bytesReceived: timestamp * 10,
            packetsReceived: videoPacketsReceived,
            packetsLost: videoPacketsLost,
            framesDecoded: timestamp / 20,
          },
        ],
        [
          "audio-inbound",
          {
            id: "audio-inbound",
            type: "inbound-rtp",
            timestamp,
            kind: "audio",
            ssrc: 202,
            trackIdentifier: "shared-audio",
            transportId: "transport",
            codecId: "audio-codec",
            bytesReceived: audioBytesReceived,
            packetsReceived: audioPacketsReceived,
            packetsLost: audioPacketsLost,
            jitter: 0.003,
          },
        ],
      ]) as unknown as RTCStatsReport;
    const reports = [
      report(1_000, 100, 5, 10_000, 1_000, 5),
      report(3_000, 190, 15, 50_000, 1_180, 10),
      report(5_000, 190, 15, 50_000, 1_180, 10, "other-transport"),
    ];
    const connection = {
      getStats: async () => reports.shift()!,
    } as unknown as RTCPeerConnection;
    const accumulator = createStatsAccumulator();

    const first = await collectConnectionMetrics(
      connection,
      "receive",
      accumulator,
    );
    const stable = await collectConnectionMetrics(
      connection,
      "receive",
      accumulator,
    );
    const zeroDenominator = await collectConnectionMetrics(
      connection,
      "receive",
      accumulator,
    );

    expect(first).toMatchObject({
      packetLossPercent: null,
      audioBitrateKbps: null,
      audioPacketLossPercent: null,
      audioJitterMs: 3,
      audioCodec: "audio/opus",
      audioCodecClockRate: 48_000,
      audioCodecChannels: 2,
      audioCodecParameters: "minptime=10;useinbandfec=1",
    });
    expect(stable.packetLossPercent).toBeCloseTo(10);
    expect(stable.audioBitrateKbps).toBeCloseTo(160);
    expect(stable.audioPacketLossPercent).toBeCloseTo((5 / 185) * 100);
    expect(zeroDenominator).toMatchObject({
      packetLossPercent: null,
      audioBitrateKbps: 0,
      audioPacketLossPercent: null,
      audioCodec: null,
      audioCodecClockRate: null,
      audioCodecChannels: null,
      audioCodecParameters: null,
    });
  });

  it("derives local inbound playout, jitter-buffer, and concealment evidence safely", async () => {
    const report = (
      timestamp: number,
      video: Record<string, unknown> = {},
      audio: Record<string, unknown> = {},
    ) =>
      new Map<string, unknown>([
        [
          "video-inbound",
          {
            id: "video-inbound",
            type: "inbound-rtp",
            timestamp,
            kind: "video",
            ssrc: 101,
            trackIdentifier: "shared-video",
            bytesReceived: timestamp * 10,
            framesDecoded: timestamp / 20,
            ...video,
          },
        ],
        [
          "audio-inbound",
          {
            id: "audio-inbound",
            type: "inbound-rtp",
            timestamp,
            kind: "audio",
            ssrc: 202,
            trackIdentifier: "shared-audio",
            bytesReceived: timestamp * 2,
            ...audio,
          },
        ],
      ]) as unknown as RTCStatsReport;
    const reports = [
      report(
        1_000,
        {
          estimatedPlayoutTimestamp: 10_000,
          jitterBufferDelay: 1.2,
          jitterBufferEmittedCount: 60,
        },
        {
          estimatedPlayoutTimestamp: 10_012.5,
          jitterBufferDelay: 960,
          jitterBufferEmittedCount: 48_000,
          totalSamplesReceived: 48_000,
          concealedSamples: 480,
          concealmentEvents: 2,
        },
      ),
      report(
        3_000,
        {
          estimatedPlayoutTimestamp: 12_000,
          jitterBufferDelay: 4.2,
          jitterBufferEmittedCount: 180,
        },
        {
          estimatedPlayoutTimestamp: 12_008.5,
          jitterBufferDelay: 3_120,
          jitterBufferEmittedCount: 144_000,
          totalSamplesReceived: 144_000,
          concealedSamples: 1_440,
          concealmentEvents: 5,
        },
      ),
      report(
        5_000,
        {
          estimatedPlayoutTimestamp: 14_000,
          jitterBufferDelay: 7.8,
          jitterBufferEmittedCount: 300,
        },
        {
          ssrc: 303,
          trackIdentifier: "replacement-audio",
          estimatedPlayoutTimestamp: 13_997,
          jitterBufferDelay: 2_000,
          jitterBufferEmittedCount: 96_000,
          totalSamplesReceived: 96_000,
          concealedSamples: 5_000,
          concealmentEvents: 30,
        },
      ),
      report(
        7_000,
        {
          estimatedPlayoutTimestamp: 16_000,
          jitterBufferDelay: 1,
          jitterBufferEmittedCount: 20,
        },
        {
          ssrc: 303,
          trackIdentifier: "replacement-audio",
          estimatedPlayoutTimestamp: 15_996,
          jitterBufferDelay: 480,
          jitterBufferEmittedCount: 24_000,
          totalSamplesReceived: 24_000,
          concealedSamples: 100,
          concealmentEvents: 1,
        },
      ),
      report(9_000, {}, { ssrc: 303, trackIdentifier: "replacement-audio" }),
    ];
    const connection = {
      getStats: async () => reports.shift()!,
    } as unknown as RTCPeerConnection;
    const accumulator = createStatsAccumulator();

    const first = await collectConnectionMetrics(
      connection,
      "receive",
      accumulator,
    );
    const stable = await collectConnectionMetrics(
      connection,
      "receive",
      accumulator,
    );
    const changedAudio = await collectConnectionMetrics(
      connection,
      "receive",
      accumulator,
    );
    const reset = await collectConnectionMetrics(
      connection,
      "receive",
      accumulator,
    );
    const unsupported = await collectConnectionMetrics(
      connection,
      "receive",
      accumulator,
    );

    expect(first).toMatchObject({
      audioVideoPlayoutDeltaMs: 12.5,
      videoJitterBufferDelayMs: null,
      audioJitterBufferDelayMs: null,
      audioConcealedSamplesPercent: null,
      intervalAudioConcealmentEvents: null,
    });
    expect(stable.audioVideoPlayoutDeltaMs).toBeCloseTo(8.5);
    expect(stable.videoJitterBufferDelayMs).toBeCloseTo(25);
    expect(stable.audioJitterBufferDelayMs).toBeCloseTo(22.5);
    expect(stable.audioConcealedSamplesPercent).toBeCloseTo(1);
    expect(stable.intervalAudioConcealmentEvents).toBe(3);
    expect(changedAudio).toMatchObject({
      audioVideoPlayoutDeltaMs: -3,
      audioJitterBufferDelayMs: null,
      audioConcealedSamplesPercent: null,
      intervalAudioConcealmentEvents: null,
    });
    expect(changedAudio.videoJitterBufferDelayMs).toBeCloseTo(30);
    expect(reset).toMatchObject({
      audioVideoPlayoutDeltaMs: -4,
      videoJitterBufferDelayMs: null,
      audioJitterBufferDelayMs: null,
      audioConcealedSamplesPercent: null,
      intervalAudioConcealmentEvents: null,
    });
    expect(unsupported).toMatchObject({
      audioVideoPlayoutDeltaMs: null,
      videoJitterBufferDelayMs: null,
      audioJitterBufferDelayMs: null,
      audioConcealedSamplesPercent: null,
      intervalAudioConcealmentEvents: null,
    });
  });

  it("uses linked remote inbound counters for outbound audio loss", async () => {
    const report = (
      timestamp: number,
      audioBytesSent: number,
      packetsReceived: number | undefined,
      packetsLost: number | undefined,
    ) =>
      new Map<string, unknown>([
        [
          "transport",
          { id: "transport", type: "transport", timestamp },
        ],
        [
          "video-outbound",
          {
            id: "video-outbound",
            type: "outbound-rtp",
            timestamp,
            kind: "video",
            ssrc: 101,
            bytesSent: timestamp * 10,
            packetsSent: timestamp / 10,
            framesEncoded: timestamp / 20,
          },
        ],
        [
          "audio-codec",
          {
            id: "audio-codec",
            type: "codec",
            timestamp,
            transportId: "transport",
            mimeType: "audio/opus",
            clockRate: 48_000,
            channels: 2,
          },
        ],
        [
          "audio-outbound",
          {
            id: "audio-outbound",
            type: "outbound-rtp",
            timestamp,
            kind: "audio",
            ssrc: 202,
            transportId: "transport",
            codecId: "audio-codec",
            remoteId: "audio-remote-inbound",
            bytesSent: audioBytesSent,
          },
        ],
        [
          "audio-remote-inbound",
          {
            id: "audio-remote-inbound",
            type: "remote-inbound-rtp",
            timestamp,
            kind: "audio",
            packetsReceived,
            packetsLost,
            jitter: 0.004,
          },
        ],
      ]) as unknown as RTCStatsReport;
    const firstReport = report(1_000, 20_000, 500, 1);
    (firstReport as unknown as Map<string, unknown>).delete(
      "audio-remote-inbound",
    );
    const reports = [
      firstReport,
      report(3_000, 50_000, 500, 1),
      report(5_000, 80_000, 650, 4),
      report(7_000, 110_000, 50, 1),
      report(9_000, 140_000, 200, undefined),
    ];
    const connection = {
      getStats: async () => reports.shift()!,
    } as unknown as RTCPeerConnection;
    const accumulator = createStatsAccumulator();

    await collectConnectionMetrics(connection, "send", accumulator);
    const remoteAppeared = await collectConnectionMetrics(
      connection,
      "send",
      accumulator,
    );
    const stable = await collectConnectionMetrics(
      connection,
      "send",
      accumulator,
    );
    const reset = await collectConnectionMetrics(
      connection,
      "send",
      accumulator,
    );
    const missing = await collectConnectionMetrics(
      connection,
      "send",
      accumulator,
    );

    expect(remoteAppeared).toMatchObject({
      audioBitrateKbps: 120,
      audioPacketLossPercent: null,
    });
    expect(stable).toMatchObject({
      audioBitrateKbps: 120,
      audioJitterMs: 4,
      audioCodec: "audio/opus",
      audioCodecClockRate: 48_000,
      audioCodecChannels: 2,
    });
    expect(stable.audioPacketLossPercent).toBeCloseTo((3 / 153) * 100);
    expect(reset.audioPacketLossPercent).toBeNull();
    expect(missing.audioPacketLossPercent).toBeNull();
  });
});