import { useMemo, useSyncExternalStore } from 'react';
import { ChevronDown, CircleHelp, Clock3, Info, PauseCircle, ShieldAlert } from 'lucide-react';
import { useI18n } from '../i18n';
import {
  authFileHealth,
  cooldownReasonKey,
  normalizeAuthFileCooldowns,
  summarizeAuthFileCooldowns,
  type AuthFileCooldownSnapshot,
} from '../services/authFileHealth';
import './AuthFileHealthStatus.css';

let clockNow = Date.now();
let timer: ReturnType<typeof setInterval> | undefined;
const listeners = new Set<() => void>();
const getClockSnapshot = () => clockNow;
const subscribeClock = (listener: () => void) => {
  listeners.add(listener);
  if (!timer) {
    clockNow = Date.now();
    timer = setInterval(() => {
      clockNow = Date.now();
      listeners.forEach((notify) => notify());
    }, 1000);
  }
  return () => {
    listeners.delete(listener);
    if (!listeners.size) {
      clearInterval(timer);
      timer = undefined;
    }
  };
};

type HealthProps = {
  file: Record<string, unknown>;
  snapshot?: AuthFileCooldownSnapshot;
};

export function AuthFileHealthStatus({ file, receivedAtMs, observedAt }: {
  file: Record<string, unknown>;
  receivedAtMs: number;
  observedAt?: string;
}) {
  const snapshot = useMemo(
    () => normalizeAuthFileCooldowns(file.cooldowns, receivedAtMs, observedAt),
    [file, receivedAtMs, observedAt],
  );
  return snapshot?.records?.length
    ? <TimedHealthStatus file={file} snapshot={snapshot} />
    : <HealthStatus file={file} snapshot={snapshot} nowMs={receivedAtMs} />;
}

function TimedHealthStatus(props: HealthProps) {
  const nowMs = useSyncExternalStore(subscribeClock, getClockSnapshot, getClockSnapshot);
  return <HealthStatus {...props} nowMs={nowMs} />;
}

function HealthStatus({ file, snapshot, nowMs }: HealthProps & { nowMs: number }) {
  const { t, formatNumber, formatDate } = useI18n();
  const health = authFileHealth(file);
  const cooldown = summarizeAuthFileCooldowns(snapshot, nowMs);
  const hasTimers = cooldown.rows.length > 0;
  const healthy = health.label === 'authFiles.health.active';
  if (healthy && !hasTimers && snapshot?.records !== null) return null;
  const hasDetails = hasTimers || Boolean(health.message);
  const reasonSet = new Set(cooldown.active.map(({ record }) => cooldownReasonKey(record.reason)));
  if (reasonSet.has('authFiles.health.reason.credentialQuota')) reasonSet.delete('authFiles.health.reason.quota');
  const reasons = Array.from(reasonSet);
  const title = health.disabled ? t(health.label)
    : cooldown.elapsed ? t('authFiles.health.elapsed')
      : cooldown.active.length ? reasons.map((key) => t(key)).join(' · ')
        : healthy ? t('authFiles.health.unknownCooldown') : t(health.label);
  const tone = health.disabled || (healthy && !hasTimers) ? 'neutral' : hasTimers ? 'warning' : health.tone;
  const separateState = hasTimers && !health.disabled && (
    health.status === 'pending' || health.status === 'refreshing'
    || health.label === 'authFiles.health.reason.invalidGrant'
    || health.label === 'authFiles.health.reason.unauthorized'
    || health.label === 'authFiles.health.reason.tokenExpired'
  );
  const Icon = health.disabled ? PauseCircle : hasTimers ? Clock3
    : tone === 'error' ? ShieldAlert
      : tone === 'warning' || tone === 'info' ? Info : CircleHelp;
  const duration = (seconds: number) => seconds < 60
    ? t('authFiles.health.seconds', { count: formatNumber(seconds) })
    : seconds < 3600 ? t('authFiles.health.minutes', { count: formatNumber(Math.ceil(seconds / 60)) })
      : t('authFiles.health.hours', { count: formatNumber(Math.ceil(seconds / 3600)) });
  const scope = cooldown.credentialWide
    ? cooldown.modelCount ? t('authFiles.health.credentialModels', { count: cooldown.modelCount })
      : t('authFiles.health.credential')
    : cooldown.modelCount ? t('authFiles.health.models', { count: cooldown.modelCount }) : '';
  const formatTimestamp = (value: string) => formatDate(value, {
    month: '2-digit', day: '2-digit', hour: '2-digit', minute: '2-digit', second: '2-digit', hour12: false,
  });
  const summary = <>
    <Icon size={16} className="auth-health-icon" aria-hidden="true" />
    <span className="auth-health-summary-content">
      <span className="auth-health-heading"><strong>{title}</strong>{scope ? <span>{scope}</span> : null}</span>
      {separateState ? <span className="auth-health-hint">{t('authFiles.health.coreStatus', { status: t(health.label) })}</span> : null}
      {health.message && !hasTimers && !health.label.startsWith('authFiles.health.reason.')
        ? <span className="auth-health-message-preview">{health.message}</span> : null}
      {cooldown.elapsed ? <span className="auth-health-hint">{t('authFiles.health.expiredHint')}</span> : null}
      {snapshot?.records === null && !healthy ? <span className="auth-health-hint">{t('authFiles.health.unknownCooldown')}</span> : null}
      {snapshot === undefined && health.tone === 'error' ? <span className="auth-health-hint">{t('authFiles.health.missingCooldown')}</span> : null}
    </span>
    {cooldown.active.length > 0 ? <span className="auth-health-countdown">
      {t('authFiles.health.earliest', { time: duration(cooldown.earliestSeconds) })}
    </span> : null}
    {hasDetails ? <span className="auth-health-disclosure"><span>{t('authFiles.health.details')}</span><ChevronDown size={14} aria-hidden="true" /></span> : null}
  </>;

  return (
    <section className={`auth-file-health ${tone}${hasDetails ? ' detailed' : ''}`} aria-label={t('authFiles.health.title')}>
      {hasDetails ? <details>
        <summary className="auth-health-summary">{summary}</summary>
        <div className="auth-health-body">
          {hasTimers && !healthy ? <p className="auth-health-core-state">{t('authFiles.health.coreStatus', { status: t(health.label) })}</p> : null}
          {health.message ? <div className="auth-health-core-message">
            <span>{t('authFiles.health.coreMessage')}</span><p>{health.message}</p>
          </div> : null}
          <ul className="auth-health-records">
            {cooldown.rows.map(({ record, remainingSeconds }, index) => (
              <li key={`${record.scope}:${record.model ?? ''}:${index}`}>
                <div className="auth-health-record-heading">
                  <strong>{record.scope === 'credential' ? t('authFiles.health.credentialScope') : record.model}</strong>
                  <span>{remainingSeconds > 0 ? t('authFiles.health.remaining', { time: duration(remainingSeconds) }) : t('authFiles.health.waiting')}</span>
                </div>
                <div className="auth-health-record-meta">
                  <span>{t(cooldownReasonKey(record.reason))}</span>
                  {record.httpStatus !== undefined ? <span>HTTP {record.httpStatus}</span> : null}
                  {record.backoffLevel !== undefined ? <span title={t('authFiles.health.backoffHint')}>{t('authFiles.health.backoff', { level: record.backoffLevel })}</span> : null}
                </div>
                <div className="auth-health-hint">{t('authFiles.health.deadline')} <time dateTime={record.retryAt}>{formatTimestamp(record.retryAt)}</time></div>
              </li>
            ))}
          </ul>
          {snapshot?.observedAt ? <p className="auth-health-hint">{t('authFiles.health.observed')} <time dateTime={snapshot.observedAt}>{formatTimestamp(snapshot.observedAt)}</time></p> : null}
          {hasTimers ? <p className="auth-health-hint">{t('authFiles.health.note')}</p> : null}
        </div>
      </details> : <div className="auth-health-summary">{summary}</div>}
    </section>
  );
}