app.py

from fastapi import FastAPI, HTTPException, UploadFile, File
from fastapi.responses import StreamingResponse
from pydantic import BaseModel
import torch
from transformers import (
    AutoTokenizer,
    AutoProcessor,
    BarkModel,
    pipeline,
    AutoModelForSequenceClassification,
    Wav2Vec2Processor,
    Wav2Vec2ForCTC
)
import scipy.io.wavfile as wavfile
import uuid
import os
from io import BytesIO
import soundfile as sf
from typing import Optional

# FastAPI instance
app = FastAPI(title="Kinyarwanda Engine", version="1.0")

# Config
MODEL_PATH = "/app/models/suno-bark"
SENTIMENT_MODEL_PATH = "/app/models/sentiment"
SAMPLE_RATE = 24000
ASR_MODEL_PATH = "lucio/wav2vec2-large-xlsr-kinyarwanda"

# Ensure working directory for audio
AUDIO_DIR = "/tmp/audio"
os.makedirs(AUDIO_DIR, exist_ok=True)

# Load models
try:
    # TTS
    tokenizer = AutoTokenizer.from_pretrained(MODEL_PATH)
    processor = AutoProcessor.from_pretrained(MODEL_PATH)
    model = BarkModel.from_pretrained(MODEL_PATH)

    # Sentiment
    sentiment_tokenizer = AutoTokenizer.from_pretrained(SENTIMENT_MODEL_PATH)
    sentiment_model = AutoModelForSequenceClassification.from_pretrained(SENTIMENT_MODEL_PATH)
    sentiment_pipeline = pipeline(
        "sentiment-analysis",
        model=sentiment_model,
        tokenizer=sentiment_tokenizer,
        truncation=True,
        max_length=512
    )

    # STT
    asr_processor = Wav2Vec2Processor.from_pretrained(ASR_MODEL_PATH)
    asr_model = Wav2Vec2ForCTC.from_pretrained(ASR_MODEL_PATH)
    asr_model.to(torch.device("cuda" if torch.cuda.is_available() else "cpu"))

    # Device config
    device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
    model.to(device)

except Exception as e:
    raise RuntimeError(f"Model initialization failed: {e}")

# Request schemas
class TTSRequest(BaseModel):
    text: str

class SentimentRequest(BaseModel):
    text: str

class LegalDocRequest(BaseModel):
    text: str
    domain: Optional[str] = "general"

# Root route
@app.get("/")
def root():
    return {"message": "Welcome to Kinyarwanda Engine"}

# Text-to-Speech endpoint
@app.post("/tts/")
def text_to_speech(request: TTSRequest):
    try:
        inputs = processor(request.text, return_tensors="pt").to(device)

        with torch.no_grad():
            audio_array = model.generate(**inputs)

        audio_data = audio_array.cpu().numpy().squeeze()
        buffer = BytesIO()
        wavfile.write(buffer, rate=SAMPLE_RATE, data=audio_data)
        buffer.seek(0)

        return StreamingResponse(
            buffer,
            media_type="audio/wav",
            headers={"Content-Disposition": f"attachment; filename=tts_{uuid.uuid4().hex}.wav"}
        )

    except Exception as e:
        raise HTTPException(status_code=500, detail=f"TTS generation failed: {str(e)}")

# Speech-to-Text endpoint
@app.post("/stt/")
def speech_to_text(audio_file: UploadFile = File(...)):
    try:
        audio_bytes = audio_file.file.read()
        audio, sample_rate = sf.read(BytesIO(audio_bytes))

        # Resample if necessary
        if sample_rate != 16000:
            import librosa
            audio = librosa.resample(audio, orig_sr=sample_rate, target_sr=16000)
            sample_rate = 16000

        inputs = asr_processor(audio, sampling_rate=sample_rate, return_tensors="pt", padding=True).input_values.to(device)

        with torch.no_grad():
            logits = asr_model(inputs).logits
            predicted_ids = torch.argmax(logits, dim=-1)

        transcription = asr_processor.batch_decode(predicted_ids)[0]
        return {"transcription": transcription}

    except Exception as e:
        raise HTTPException(status_code=500, detail=f"STT failed: {str(e)}")

# Sentiment Analysis endpoint
@app.post("/sentiment/")
def analyze_sentiment(request: SentimentRequest):
    try:
        result = sentiment_pipeline(request.text)
        return {"result": result}
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Sentiment analysis failed: {str(e)}")

# Legal Parsing endpoint
@app.post("/legal-parse/")
def parse_legal_document(request: LegalDocRequest):
    try:
        keywords = ["contract", "agreement", "party", "terms", "confidential", "jurisdiction"]
        found = [kw for kw in keywords if kw in request.text.lower()]
        return {
            "identified_keywords": found,
            "domain": request.domain,
            "status": "success"
        }
    except Exception as e:
        raise HTTPException(status_code=500, detail=f"Legal parsing failed: {str(e)}")