evOo-local/apps/mobile/lib/sound.ts

import type { OoSoundCue, SoundDriver } from "@rakazo/core";
import { CUE_RECIPES, PcmWavSynthesizer } from "@rakazo/core";
import { File, Paths } from "expo-file-system";

export class ExpoMobileSoundDriver implements SoundDriver {
  private cacheDir = `${Paths.cache}/earcons`;
  private cachedUris = new Map<OoSoundCue, string>();

  isSupported(): boolean {
    return true;
  }

  async play(cue: OoSoundCue): Promise<void> {
    if (!CUE_RECIPES[cue]) return;

    // Check if HTML5 audio is present (mobile web fallback / test environment)
    const AudioCtor = (globalThis as { Audio?: typeof Audio }).Audio;
    if (typeof AudioCtor === "function" && typeof window !== "undefined") {
      const wav = PcmWavSynthesizer.renderCueWav(cue);
      const blob = new Blob([wav as Uint8Array<ArrayBuffer>], { type: "audio/wav" });
      const url = URL.createObjectURL(blob);
      try {
        const audio = new AudioCtor(url);
        await audio.play().catch(() => undefined);
      } finally {
        setTimeout(() => URL.revokeObjectURL(url), 2000);
      }
      return;
    }

    // Native Expo Audio playback
    try {
      const { createAudioPlayer, setAudioModeAsync } = await import("expo-audio");
      await setAudioModeAsync({
        playsInSilentMode: true,
        interruptionMode: "mixWithOthers",
        shouldPlayInBackground: false,
      });

      let uri = this.cachedUris.get(cue);
      if (!uri) {
        const wav = PcmWavSynthesizer.renderCueWav(cue);
        const file = new File(this.cacheDir, `earcon-${cue}.wav`);
        file.create({ overwrite: true });
        file.write(this.bytesToBase64(wav), { encoding: "base64" });
        uri = file.uri;
        this.cachedUris.set(cue, uri);
      }

      const player = createAudioPlayer({ uri });
      player.play();
      setTimeout(() => player.release(), 2000);
    } catch {
      // Best-effort degradation
    }
  }

  private bytesToBase64(bytes: Uint8Array): string {
    if (typeof Buffer !== "undefined") return Buffer.from(bytes).toString("base64");
    let binary = "";
    const chunk = 0x8000;
    for (let i = 0; i < bytes.length; i += chunk) {
      binary += String.fromCharCode(...bytes.subarray(i, i + chunk));
    }
    return btoa(binary);
  }
}

export const mobileSound = new ExpoMobileSoundDriver();