/**
 * Shared capture helpers for live-encode / clip-studio demos.
 */
(function (global) {
  'use strict';

  function startCapture(kind) {
    if (kind === 'camera') {
      return navigator.mediaDevices.getUserMedia({
        video: { width: { ideal: 1280 }, height: { ideal: 720 } },
        audio: false,
      });
    }
    return navigator.mediaDevices.getDisplayMedia({
      video: { frameRate: { ideal: 30 } },
      audio: false,
    });
  }

  /**
   * Pump video element frames onto a canvas at target FPS, calling onFrame(canvas).
   * Returns { stop, canvas, setFps }.
   */
  function startFramePump(videoEl, opts) {
    opts = opts || {};
    var fps = opts.fps || 10;
    var maxW = opts.maxWidth || 640;
    var maxH = opts.maxHeight || 360;
    var canvas = opts.canvas || document.createElement('canvas');
    var ctx = canvas.getContext('2d', { alpha: false });
    var running = true;
    var timer = null;
    var lastPush = 0;
    var inflight = false;

    function sizeCanvas() {
      var vw = videoEl.videoWidth || maxW;
      var vh = videoEl.videoHeight || maxH;
      var scale = Math.min(maxW / vw, maxH / vh, 1);
      canvas.width = Math.max(2, Math.round(vw * scale / 2) * 2);
      canvas.height = Math.max(2, Math.round(vh * scale / 2) * 2);
    }

    function tick() {
      if (!running) return;
      var interval = 1000 / fps;
      var now = performance.now();
      if (now - lastPush >= interval && !inflight && videoEl.readyState >= 2 && videoEl.videoWidth) {
        lastPush = now;
        if (!canvas.width || !canvas.height) sizeCanvas();
        try {
          ctx.drawImage(videoEl, 0, 0, canvas.width, canvas.height);
        } catch (_) {}
        if (typeof opts.onFrame === 'function') {
          inflight = true;
          Promise.resolve(opts.onFrame(canvas))
            .catch(function () {})
            .finally(function () { inflight = false; });
        }
      }
      timer = requestAnimationFrame(tick);
    }

    function kickPlay() {
      try {
        videoEl.muted = true;
        videoEl.playsInline = true;
        videoEl.autoplay = true;
        var p = videoEl.play();
        if (p && typeof p.catch === 'function') p.catch(function () {});
      } catch (_) {}
    }

    videoEl.addEventListener('loadedmetadata', function () {
      sizeCanvas();
      kickPlay();
    });
    if (videoEl.videoWidth) sizeCanvas();
    kickPlay();
    timer = requestAnimationFrame(tick);

    return {
      canvas: canvas,
      stop: function () {
        running = false;
        if (timer) cancelAnimationFrame(timer);
        timer = null;
      },
      setFps: function (n) {
        fps = Math.max(1, Math.min(30, Number(n) || fps));
      },
      setMaxSize: function (w, h) {
        maxW = w;
        maxH = h;
        sizeCanvas();
      },
    };
  }

  global.BridgeSwarmLiveCapture = {
    startCapture: startCapture,
    startFramePump: startFramePump,
  };
})(typeof window !== 'undefined' ? window : globalThis);