/**
 * POST /api/coach/speak
 * Empfängt text → FreeTTS (Microsoft Neural Voices, kostenlos) → gibt base64 Audio zurück
 */
export default defineEventHandler(async (event) => {
  await requireUser(event);

  const body = await readBody(event);
  const { text } = body as { text: string };

  if (!text?.trim()) {
    throw createError({ statusCode: 400, message: "text fehlt" });
  }

  // Max 4096 Zeichen
  const trimmed = text.slice(0, 4096);

  try {
    // FreeTTS API - free, no key required
    const response = await fetch("https://freetts.org/api/tts", {
      method: "POST",
      headers: {
        "Content-Type": "application/json",
      },
      body: JSON.stringify({
        text: trimmed,
        voice: "de-DE-KatjaNeural",
        speed: 1.0,
        output: "mp3",
      }),
    });

    const responseText = await response.text();
    console.log("[speak] FreeTTS response status:", response.status);
    console.log("[speak] FreeTTS response body:", responseText);

    if (!response.ok) {
      console.error("[speak] FreeTTS error:", response.status, responseText);
      throw createError({ statusCode: 502, message: `TTS fehlgeschlagen: ${responseText}` });
    }

    // FreeTTS returns a file_id to download
    const result = JSON.parse(responseText);
    
    if (!result.file_id) {
      console.error("[speak] FreeTTS no file_id:", result);
      throw createError({ statusCode: 502, message: "TTS fehlgeschlagen: no file_id" });
    }

    // Download the audio file from correct endpoint
    console.log("[speak] Downloading audio file:", result.file_id);
    const audioResponse = await fetch(`https://freetts.org/api/audio/${result.file_id}`);
    
    if (!audioResponse.ok) {
      console.error("[speak] Audio download failed:", audioResponse.status);
      throw createError({ statusCode: 502, message: "TTS fehlgeschlagen: download failed" });
    }

    const audioBuffer = await audioResponse.arrayBuffer();
    const base64 = Buffer.from(audioBuffer).toString("base64");

    return { audio: `data:audio/mp3;base64,${base64}` };
  } catch (err: any) {
    console.error("[speak] TTS error:", err?.message || err);
    throw createError({
      statusCode: 502,
      message: err?.message || "TTS fehlgeschlagen",
    });
  }
});