routes/audio.py

from fastapi import APIRouter, UploadFile, File, HTTPException
from fastapi.responses import StreamingResponse
import io
import logging
from config import ALLOWED_AUDIO_TYPES, MAX_AUDIO_SIZE
from services.stt_service import speech_to_text, load_stt_model
from services.tts_service import generate_tts
from services.chatbot_service import get_chatbot_response, load_chatbot_model
from models.audio import STTResponse, TTSRequest, TTSResponse, ChatbotRequest, ChatbotResponse

logger = logging.getLogger(__name__)

router = APIRouter(prefix="/audio", tags=["Audio"])

# Pre-load models on router startup
@router.on_event("startup")
async def startup_event():
    """Load models when the router starts"""
    logger.info("Loading free STT and Chatbot models...")
    load_stt_model()
    load_chatbot_model()


@router.post("/tts")
async def tts(request: TTSRequest):
    """
    Convert text to speech and return audio file using free gTTS.
    
    Example:
    - POST /audio/tts
    - Body: {"text": "Hello, welcome to our system"}
    - Returns: MP3 audio file
    """
    try:
        logger.info(f"TTS request received for text: '{request.text}'")
        audio_bytes = await generate_tts(request.text)
        return StreamingResponse(io.BytesIO(audio_bytes), media_type="audio/mp3")
    except Exception as e:
        logger.error(f"TTS error: {str(e)}")
        raise HTTPException(status_code=500, detail=str(e))


@router.post("/stt", response_model=STTResponse)
async def stt(file: UploadFile = File(...)):
    """
    Convert audio file to text using free Whisper model.
    
    Example:
    - POST /audio/stt
    - File: audio.mp3 (or .wav, .m4a)
    - Returns: {"text": "transcribed text", "model_name": "whisper-small", ...}
    """
    # Validate file type
    if file.content_type not in ALLOWED_AUDIO_TYPES:
        raise HTTPException(
            status_code=400,
            detail=f"Unsupported format: {file.content_type}. Supported: WAV, MP3, M4A"
        )
    
    try:
        logger.info(f"STT request received for file: {file.filename}")
        audio_bytes = await file.read()
        
        # Check file size
        if len(audio_bytes) > MAX_AUDIO_SIZE:
            raise HTTPException(
                status_code=400,
                detail=f"Audio file too large. Max size: {MAX_AUDIO_SIZE / 1024 / 1024}MB"
            )
        
        text = await speech_to_text(audio_bytes, file.filename)
        
        return STTResponse(
            text=text,
            model_name="whisper-small",
            language="en",
            duration_seconds=None
        )
    except Exception as e:
        logger.error(f"STT error: {str(e)}")
        raise HTTPException(status_code=500, detail=str(e))


@router.post("/chatbot")
async def chatbot_voice(file: UploadFile = File(...)):
    """
    Full voice chatbot flow using free models (Audio → Text → Response → Audio).
    
    Example:
    - POST /audio/chatbot
    - File: user_voice.mp3
    - Returns: Response audio file (MP3)
    """
    # Validate file type
    if file.content_type not in ALLOWED_AUDIO_TYPES:
        raise HTTPException(
            status_code=400,
            detail=f"Unsupported format: {file.content_type}. Supported: WAV, MP3, M4A"
        )
    
    try:
        logger.info(f"Voice chatbot request received for file: {file.filename}")
        
        # Step 1: Convert audio to text
        audio_bytes = await file.read()
        
        # Check file size
        if len(audio_bytes) > MAX_AUDIO_SIZE:
            raise HTTPException(
                status_code=400,
                detail=f"Audio file too large. Max size: {MAX_AUDIO_SIZE / 1024 / 1024}MB"
            )
            
        user_text = await speech_to_text(audio_bytes, file.filename)
        logger.info(f"Step 1 - STT: {user_text}")
        
        # Step 2: Generate chatbot response
        response_text = await get_chatbot_response(user_text)
        logger.info(f"Step 2 - Response: {response_text}")
        
        # Step 3: Convert response to audio
        audio_response = await generate_tts(response_text)
        logger.info("Step 3 - TTS: Complete")
        
        return StreamingResponse(io.BytesIO(audio_response), media_type="audio/mp3")
        
    except Exception as e:
        logger.error(f"Voice chatbot error: {str(e)}")
        raise HTTPException(status_code=500, detail=str(e))


@router.post("/chatbot-text", response_model=ChatbotResponse)
async def chatbot_text(request: ChatbotRequest):
    """
    Chatbot interaction with text input/output using free DialoGPT model.
    
    Example:
    - POST /audio/chatbot-text
    - Body: {"text": "What is the capital of France?"}
    - Returns: {"user_input": "What is...", "bot_response": "The capital...", ...}
    """
    try:
        logger.info(f"Text chatbot request: {request.text}")
        response_text = await get_chatbot_response(request.text)
        
        return ChatbotResponse(
            user_input=request.text,
            bot_response=response_text,
            model_name="DialoGPT-medium"
        )
    except Exception as e:
        logger.error(f"Text chatbot error: {str(e)}")
        raise HTTPException(status_code=500, detail=str(e))