maternal-app/maternal-web/app/api/voice/transcribe/route.ts

import { NextRequest, NextResponse } from 'next/server';
import { classifyIntent, validateClassification, getConfidenceLevel } from '@/lib/voice/intentClassifier';

/**
 * Voice transcription and intent classification endpoint
 *
 * Accepts audio file or transcribed text and returns:
 * - Intent classification (feeding/sleep/diaper)
 * - Extracted entities (amounts, times, durations)
 * - Structured data ready for activity creation
 */
export async function POST(request: NextRequest) {
  try {
    const contentType = request.headers.get('content-type') || '';

    let transcribedText: string;

    if (contentType.includes('application/json')) {
      // Text input (already transcribed) - forward to backend for LLM classification
      const body = await request.json();
      transcribedText = body.text;

      if (!transcribedText || typeof transcribedText !== 'string') {
        return NextResponse.json(
          {
            error: 'VOICE_INVALID_INPUT',
            message: 'Text must be a non-empty string',
          },
          { status: 400 }
        );
      }

      // Forward text to backend for LLM-based classification
      const backendUrl = process.env.NEXT_PUBLIC_API_URL || 'http://localhost:3020';
      const backendResponse = await fetch(`${backendUrl}/api/v1/voice/transcribe`, {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
          // Forward auth token if present
          ...(request.headers.get('authorization') && {
            authorization: request.headers.get('authorization')!,
          }),
        },
        body: JSON.stringify({
          text: transcribedText,
          language: body.language || 'en',
          childName: body.childName,
        }),
      });

      if (!backendResponse.ok) {
        const errorData = await backendResponse.json();
        return NextResponse.json(errorData, { status: backendResponse.status });
      }

      const result = await backendResponse.json();

      // Backend returns { success, transcript, classification }
      return NextResponse.json(
        {
          success: true,
          transcript: result.transcript,
          classification: result.classification,
        },
        { status: 200 }
      );
    } else if (contentType.includes('multipart/form-data')) {
      // Audio file upload - forward to backend for Whisper transcription
      const formData = await request.formData();
      const audioFile = formData.get('audio');

      if (!audioFile) {
        return NextResponse.json(
          {
            error: 'VOICE_NO_AUDIO',
            message: 'No audio file provided',
          },
          { status: 400 }
        );
      }

      // Forward to backend
      const backendUrl = process.env.NEXT_PUBLIC_API_URL || 'http://localhost:3020';
      const backendFormData = new FormData();
      backendFormData.append('audio', audioFile);

      const backendResponse = await fetch(`${backendUrl}/api/v1/voice/transcribe`, {
        method: 'POST',
        body: backendFormData,
        headers: {
          // Forward auth token if present
          ...(request.headers.get('authorization') && {
            authorization: request.headers.get('authorization')!,
          }),
        },
      });

      if (!backendResponse.ok) {
        const errorData = await backendResponse.json();
        return NextResponse.json(errorData, { status: backendResponse.status });
      }

      const result = await backendResponse.json();

      // Backend returns { success, transcript, classification }
      // Return in the format expected by the frontend
      return NextResponse.json(
        {
          success: true,
          transcript: result.transcript,
          classification: result.classification,
        },
        { status: 200 }
      );
    } else {
      return NextResponse.json(
        {
          error: 'VOICE_INVALID_CONTENT_TYPE',
          message: 'Content-Type must be application/json or multipart/form-data',
        },
        { status: 400 }
      );
    }

    // Classify intent
    const classification = classifyIntent(transcribedText);

    // Validate classification
    if (!validateClassification(classification)) {
      return NextResponse.json(
        {
          error: 'VOICE_CLASSIFICATION_FAILED',
          message: 'Could not understand the command. Please try again.',
          suggestion: 'Try saying something like "Fed baby 100ml" or "Changed wet diaper"',
          classification: {
            intent: classification.intent,
            confidence: classification.confidence,
            confidenceLevel: getConfidenceLevel(classification.confidence),
          },
        },
        { status: 400 }
      );
    }

    // Return classification result
    return NextResponse.json(
      {
        success: true,
        transcription: transcribedText,
        classification: {
          intent: classification.intent,
          confidence: classification.confidence,
          confidenceLevel: getConfidenceLevel(classification.confidence),
          entities: classification.entities,
          structuredData: classification.structuredData,
        },
      },
      { status: 200 }
    );
  } catch (error) {
    console.error('[Voice] Transcription error:', error);
    return NextResponse.json(
      {
        error: 'VOICE_TRANSCRIPTION_FAILED',
        message: 'Failed to process voice command. Please try again.',
      },
      { status: 500 }
    );
  }
}

/**
 * Get supported voice commands and examples
 */
export async function GET() {
  return NextResponse.json(
    {
      supportedIntents: ['feeding', 'sleep', 'diaper'],
      examples: {
        feeding: [
          'Fed baby 120 ml',
          'Gave him 4 ounces',
          'Nursed on left breast for 15 minutes',
          'Breastfed on both sides',
          'Baby ate solid food',
        ],
        sleep: [
          'Baby fell asleep',
          'Napped for 45 minutes',
          'Put baby down for bedtime',
          'Baby woke up',
        ],
        diaper: [
          'Changed wet diaper',
          'Dirty diaper change',
          'Changed a wet and dirty diaper',
          'Baby had a bowel movement',
        ],
      },
      entities: {
        amounts: ['120 ml', '4 oz', '2 tablespoons'],
        durations: ['15 minutes', '45 mins', '2 hours'],
        times: ['at 3:30 pm', '30 minutes ago', 'just now'],
        breastSides: ['left breast', 'right side', 'both sides'],
        diaperTypes: ['wet', 'dirty', 'wet and dirty', 'bowel movement'],
      },
    },
    { status: 200 }
  );
}