app/app/api/tts/route.ts

import { NextRequest, NextResponse } from 'next/server';
import { createClient } from '@deepgram/sdk';

/**
 * Text-to-Speech API route using Deepgram Aura
 *
 * Converts text to natural-sounding speech using Deepgram's Aura-2 model.
 * Returns audio data that can be played in the browser.
 */
export async function POST(request: NextRequest) {
  const deepgramApiKey = process.env.DEEPGRAM_API_KEY;

  if (!deepgramApiKey) {
    return NextResponse.json(
      { error: 'Deepgram API key not configured' },
      { status: 500 }
    );
  }

  try {
    const { text } = await request.json();

    if (!text || typeof text !== 'string') {
      return NextResponse.json(
        { error: 'Text parameter is required' },
        { status: 400 }
      );
    }

    console.log('[TTS] Generating speech for text:', text.substring(0, 50) + '...');

    const deepgram = createClient(deepgramApiKey);

    // Generate speech using Deepgram Aura
    const response = await deepgram.speak.request(
      { text },
      {
        model: 'aura-2-thalia-en', // Natural female voice
        encoding: 'linear16',
        container: 'wav',
      }
    );

    // Get the audio stream
    const stream = await response.getStream();

    if (!stream) {
      throw new Error('No audio stream returned from Deepgram');
    }

    // Convert stream to buffer
    const chunks: Uint8Array[] = [];
    const reader = stream.getReader();

    try {
      while (true) {
        const { done, value } = await reader.read();
        if (done) break;
        if (value) chunks.push(value);
      }
    } finally {
      reader.releaseLock();
    }

    const buffer = Buffer.concat(chunks);

    console.log('[TTS] ✓ Generated', buffer.length, 'bytes of audio');

    // Return audio with proper headers
    return new NextResponse(buffer, {
      headers: {
        'Content-Type': 'audio/wav',
        'Content-Length': buffer.length.toString(),
      },
    });
  } catch (error) {
    console.error('[TTS] Error generating speech:', error);
    return NextResponse.json(
      { error: 'Failed to generate speech' },
      { status: 500 }
    );
  }
}