// Chooses how a feed video plays. Pure, so it is unit-testable without a browser.

export type Playback = "none" | "native" | "hlsjs";

export interface PlaybackEnv {
  /** True when the browser can play .m3u8 directly (Safari). */
  nativeHls: boolean;
  /** True when hls.js (Media Source Extensions) is supported. */
  hlsJsSupported: boolean;
}

/**
 * No hlsUrl: thumbnail only. hls.js (Media Source Extensions) is preferred
 * because Chromium reports partial native HLS support it cannot honour; native
 * HLS is only chosen where hls.js is unsupported (Safari on iOS).
 */
export function choosePlayback(hlsUrl: string | null | undefined, env: PlaybackEnv): Playback {
  if (!hlsUrl) return "none";
  if (env.hlsJsSupported) return "hlsjs";
  return env.nativeHls ? "native" : "none";
}

export function supportsNativeHls(video: Pick<HTMLVideoElement, "canPlayType">): boolean {
  return video.canPlayType("application/vnd.apple.mpegurl") !== "";
}