// Global store: manifest, playhead (t_global), playing, rate, selected camera, audio source,
// plus the loaded poses / anchors / events and per-video live playback status. Single source
// of truth: the transport writes `tGlobal` every animation frame; every module reads it.
// Discrete changes (play/pause/seek/selection) go through the tiny pub/sub below.

// API origin/prefix. Local dev talks to the uvicorn server cross-origin on :8000 (default).
// A hosted build sets VITE_API_BASE to a same-origin path prefix (e.g. "/festifun") so every
// request — fetch, <video> src, PLY loader — goes through the reverse proxy under that path.
// Empty string = same-origin at root. See deploy/DEPLOY.md.
// Phase-5 contract #5: a RUNTIME override wins over the build-time value — the memory capsule
// (M17) injects `window.__F4D_API_BASE__ = ""` into its baked index.html so the same dist
// bundle turns zero-backend. `??` (not `||`): empty string is a valid value (same-origin).
export const API_BASE =
  window.__F4D_API_BASE__ ?? import.meta.env.VITE_API_BASE ?? "http://localhost:8000";

export const state = {
  apiBase: API_BASE,

  // loaded from the API (see main.js boot)
  manifest: null,
  videos: [], // [{id, filename, url, duration_s, fps, width, height, offset_ms, drift_ppm}]
  tGlobalMax: 0,
  hasPoses: false,
  hasSplat: false, // optional 3DGS splat at /api/splat (preferred over the point cloud)
  capsule: false, // manifest.capsule (M17): static baked bundle => hide ALL write UI
  poses: {}, // id -> [{frame_idx, t_video_s, q:[w,x,y,z], t:[x,y,z], intrinsics, registered}]
  anchors: [], // [{id, label, x, y, z, color}]
  events: [], // [{id, t_global_s, duration_s, event_type, confidence, description, source}]
  hasTracks: false, // manifest.has_tracks (M18): any solved friend track => load + render tracks
  tracks: [], // [{id, marker_key, label, color, points:[{t_global_s,x,y,z,quality,views}]}] (M18)

  // transport / playback
  tGlobal: 0,
  playing: false,
  rate: 1,
  audioSourceId: null, // video id whose audio you hear (WebAudio soundtrack; fallback: unmuted <video>)
  spatialAudio: false, // 🎧 every camera is a positional emitter at its 3D pose; listener = viewer cam
  enabled: {}, // id -> bool (per-video enable; disabled videos pause + dim + drop from sync)
  inRange: {}, // id -> bool (t_video within [0, duration] and enabled)
  syncErrorMs: {}, // id -> number | null (currentTime - target, ms; null when out of range)

  // 3D viewer
  followCameraId: null, // video id the viewer camera is snapped to, or null for free roam
};

// --- tiny pub/sub for discrete events -------------------------------------------------------
const listeners = new Map();

/** Subscribe to an event; returns an unsubscribe fn. */
export function on(evt, fn) {
  if (!listeners.has(evt)) listeners.set(evt, new Set());
  listeners.get(evt).add(fn);
  return () => listeners.get(evt)?.delete(fn);
}

/** Emit an event to all subscribers. */
export function emit(evt, payload) {
  const set = listeners.get(evt);
  if (set) for (const fn of [...set]) fn(payload);
}

/** The reference video (offset 0) if present, else the first video. Used as default audio source. */
export function referenceVideoId() {
  const ref = state.videos.find((v) => (v.offset_ms ?? 0) === 0);
  return ref ? ref.id : state.videos[0]?.id ?? null;
}