// MediaMTX control API, proxied by Caddy at /api (-> 127.0.0.1:9997). Returns active streams.
const VIDEO = new Set(['H264', 'H265', 'VP8', 'VP9', 'AV1', 'MJPEG', 'M-JPEG', 'MPEG-4 Video', 'MPEG-1 Video'])
const firstSeen = new Map()                      // path -> first time we saw it ready (mirror grace period)
const MIRROR_WAIT_MS = 15000

export async function fetchStreams() {
  const r = await fetch('/api/v3/paths/list?itemsPerPage=200', { credentials: 'same-origin' })
  if (!r.ok) throw new Error(`api ${r.status}`)
  const data = await r.json()
  const ready = (data.items || []).filter(p => p.ready && (p.tracks || []).length > 0)
  const byName = new Map(ready.map(p => [p.name, p]))
  const now = Date.now()
  for (const p of ready) if (!firstSeen.has(p.name)) firstSeen.set(p.name, now)
  for (const k of [...firstSeen.keys()]) if (!byName.has(k)) firstSeen.delete(k)
  const out = []
  for (const p of ready) {
    if (p.name.endsWith('.webrtc')) continue       // audio mirror: played through its source's panel, never its own
    const tracks = p.tracks || []
    const audio = tracks.filter(t => !VIDEO.has(t))
    const needsMirror = audio.length > 0 && !audio.includes('Opus')   // AAC etc. cannot cross WebRTC
    const mirror = byName.get(p.name + '.webrtc')
    if (needsMirror && !mirror && now - firstSeen.get(p.name) < MIRROR_WAIT_MS) continue   // give the mirror a moment to come up
    const [user, ...rest] = p.name.split('/')
    out.push({
      id: p.name,                                  // e.g. techy/VanguardTraining
      user,
      title: rest.join('/') || p.name,
      whep: mirror ? mirror.name : p.name,         // WebRTC plays the Opus mirror when there is one; HLS always the source
      viewers: (p.readers || []).length + (mirror ? (mirror.readers || []).length - 1 : 0),   // the mirror's ffmpeg is one reader
      since: p.readyTime,
      tracks,
    })
  }
  return out.sort((a, b) => (a.since || '').localeCompare(b.since || ''))
}

export const whepUrl = id => `/webrtc/${id}/whep`
export const hlsUrl  = id => `/hls/${id}/index.m3u8`