// 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. Native HLS wins; hls.js is the fallback. */
export function choosePlayback(hlsUrl: string | null | undefined, env: PlaybackEnv): Playback {
  if (!hlsUrl) return "none";
  if (env.nativeHls) return "native";
  return env.hlsJsSupported ? "hlsjs" : "none";
}

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