import AppKit
import SwiftUI

@MainActor
final class HUDModel: ObservableObject {
    enum Phase {
        case preparing
        case listening
        case processing
    }

    @Published var text: String = ""
    @Published var level: Float = 0
    @Published var phase: Phase = .listening
    @Published var hint: String = "再按一次结束 · Esc 取消"
}

struct HUDView: View {
    @ObservedObject var model: HUDModel

    var body: some View {
        HStack(alignment: .center, spacing: 14) {
            Waveform(level: model.level, active: model.phase == .listening)
                .frame(width: 34, height: 34)

            VStack(alignment: .leading, spacing: 5) {
                HStack(spacing: 6) {
                    if model.phase != .listening {
                        ProgressView()
                            .controlSize(.small)
                            .scaleEffect(0.7)
                    }
                    Text(displayText)
                        .font(.system(size: 15, weight: .regular))
                        .foregroundStyle(model.text.isEmpty ? Color.secondary : Color.primary)
                        .lineLimit(3)
                        .multilineTextAlignment(.leading)
                        .fixedSize(horizontal: false, vertical: true)
                }
                Text(model.phase == .preparing ? "等待本地引擎就绪后再说话 · Esc 取消" : (model.phase == .processing ? "正在整理文字…" : model.hint))
                    .font(.system(size: 11))
                    .foregroundStyle(.secondary)
            }
            Spacer(minLength: 0)
        }
        .padding(.horizontal, 16)
        .padding(.vertical, 12)
        .frame(width: 480, height: 104, alignment: .leading)
        .background(
            RoundedRectangle(cornerRadius: 18, style: .continuous)
                .fill(.regularMaterial)
        )
        .overlay(
            RoundedRectangle(cornerRadius: 18, style: .continuous)
                .strokeBorder(Color.primary.opacity(0.09), lineWidth: 0.5)
        )
    }

    private var displayText: String {
        if model.text.isEmpty {
            return model.phase == .preparing ? "正在准备本地识别…" : (model.phase == .processing ? " " : "聆听中…")
        }
        return model.text
    }
}

private struct Waveform: View {
    var level: Float
    var active: Bool

    var body: some View {
        HStack(alignment: .center, spacing: 3) {
            ForEach(0..<5, id: \.self) { index in
                Capsule()
                    .fill(active ? Color.accentColor : Color.secondary.opacity(0.4))
                    .frame(width: 3, height: height(for: index))
            }
        }
        .frame(maxWidth: .infinity, maxHeight: .infinity)
        .animation(.easeOut(duration: 0.12), value: level)
    }

    private func height(for index: Int) -> CGFloat {
        let weights: [CGFloat] = [0.45, 0.75, 1.0, 0.7, 0.5]
        let base: CGFloat = 5
        let maxHeight: CGFloat = 30
        let l = CGFloat(max(0, min(1, level)))
        return base + (maxHeight - base) * l * weights[index]
    }
}

@MainActor
final class HUDController {
    private var panel: NSPanel?
    private var tracking: Timer?
    private let model = HUDModel()

    var isVisible: Bool { panel?.isVisible ?? false }

    func show() {
        model.text = ""
        model.level = 0
        model.phase = .preparing
        model.hint = "\(Prefs.shared.languageCode) · " + (Prefs.shared.triggerMode == .hold ? "松开结束 · Esc 取消" : "再按一次结束 · Esc 取消")

        let panel = ensurePanel()
        position(panel)
        panel.alphaValue = 0
        panel.orderFrontRegardless()
        tracking?.invalidate()
        tracking = Timer.scheduledTimer(withTimeInterval: 0.3, repeats: true) { [weak self] _ in
            MainActor.assumeIsolated {
                guard let self, let panel = self.panel else { return }
                self.position(panel)
            }
        }
        NSAnimationContext.runAnimationGroup { context in
            context.duration = 0.12
            panel.animator().alphaValue = 1
        }
    }

    func update(text: String) {
        model.text = text
    }

    func update(level: Float) {
        // 平滑一下，避免抖动
        model.level = model.level * 0.6 + level * 0.4
    }

    func setListening() { model.phase = .listening }

    func setProcessing() {
        model.phase = .processing
    }

    func hide() {
        tracking?.invalidate()
        tracking = nil
        guard let panel, panel.isVisible else { return }
        panel.orderOut(nil)
    }

    private func ensurePanel() -> NSPanel {
        if let panel { return panel }

        let panel = CaptionPanel(
            contentRect: NSRect(x: 0, y: 0, width: 480, height: 104),
            styleMask: [.borderless, .nonactivatingPanel],
            backing: .buffered,
            defer: false
        )
        panel.isFloatingPanel = true
        panel.level = .statusBar
        panel.isOpaque = false
        panel.backgroundColor = .clear
        panel.hasShadow = true
        panel.ignoresMouseEvents = true
        panel.hidesOnDeactivate = false
        panel.becomesKeyOnlyIfNeeded = false
        panel.collectionBehavior = [.canJoinAllSpaces, .fullScreenAuxiliary, .stationary, .ignoresCycle]
        panel.contentView = NSHostingView(rootView: HUDView(model: model))
        self.panel = panel
        return panel
    }

    private func position(_ panel: NSPanel) {
        let size = panel.frame.size
        let screen = screenUnderMouse() ?? NSScreen.main
        guard let screen else { return }

        var origin: CGPoint

        if !Prefs.shared.hudAtBottom, let ax = Inserter.focusedFrame() {
            // AX 坐标系：主屏左上角为原点，y 向下
            let primaryHeight = NSScreen.screens
                .first { $0.frame.origin == .zero }?.frame.height ?? screen.frame.height
            let appKitY = primaryHeight - ax.maxY
            var x = ax.minX + ax.width / 2 - size.width / 2
            var y = appKitY - size.height - 10

            // 下方空间不够时显示到输入框上方
            if y < screen.visibleFrame.minY + 8 {
                y = primaryHeight - ax.minY + 10
            }
            x = min(max(x, screen.visibleFrame.minX + 8), screen.visibleFrame.maxX - size.width - 8)
            y = min(max(y, screen.visibleFrame.minY + 8), screen.visibleFrame.maxY - size.height - 8)
            origin = CGPoint(x: x, y: y)
        } else {
            origin = CGPoint(x: screen.frame.midX - size.width / 2,
                             y: screen.visibleFrame.minY + 120)
        }

        panel.setFrame(NSRect(origin: origin, size: size), display: true)
    }

    private func screenUnderMouse() -> NSScreen? {
        let location = NSEvent.mouseLocation
        return NSScreen.screens.first { $0.frame.contains(location) }
    }
}

private final class CaptionPanel: NSPanel {
    override var canBecomeKey: Bool { false }
    override var canBecomeMain: Bool { false }
}