app/main.py

import os
import shutil
import uuid
import time
from dotenv import load_dotenv
from fastapi import FastAPI, File, UploadFile, Form, Request
from fastapi.responses import HTMLResponse, FileResponse
from fastapi.staticfiles import StaticFiles
from fastapi.templating import Jinja2Templates

from app.services.transcribe import extract_audio, transcribe_audio
from app.services.srt_generator import save_srt, translate_srt
from app.services.precision_patch import apply_precision_patch
from app.services.translators.deep_translator_adapter import DeepTranslatorAdapter

# Load environment variables from .env
load_dotenv()

app = FastAPI(title="AI Subtitle Generator")

# Create required directories
os.makedirs("app/uploads", exist_ok=True)
os.makedirs("app/subtitles", exist_ok=True)
os.makedirs("app/static", exist_ok=True)
os.makedirs("app/templates", exist_ok=True)

app.mount("/static", StaticFiles(directory="app/static"), name="static")
templates = Jinja2Templates(directory="app/templates")

# Whisper Phonetic Bias List
WHISPER_PROMPT = "Naukri, NotebookLM, Razorpay, LinkedIn, Bay Area, San Francisco, notebooklm.google.com"

# Project-wide Glossary for AI Job Hunt and tech context
PROJECT_GLOSSARY = {
    "Naukri": "Naukri",
    "NotebookLM": "NotebookLM",
    "Razorpay": "Razorpay",
    "LinkedIn": "LinkedIn",
    "notebooklm.google.com": "notebooklm.google.com",
    "nerve-wracking": "ആവേശകരമായ",  # Contextual mapping for Malayalam
    "see you": "കാണാം",            # Cultural closing
}

def get_translator(provider: str):
    """Instantiate the chosen translation adapter. Falls back to Google Translate."""
    if provider == "groq":
        try:
            from app.services.translators.groq_adapter import GroqAdapter
            return GroqAdapter()
        except Exception as e:
            print(f"Groq unavailable ({e}), falling back to Google Translate.")
            return DeepTranslatorAdapter()
    elif provider == "gemini":
        try:
            from app.services.translators.gemini_adapter import GeminiAdapter
            return GeminiAdapter()
        except Exception as e:
            print(f"Gemini unavailable ({e}), falling back to Google Translate.")
            return DeepTranslatorAdapter()
    return DeepTranslatorAdapter()

@app.get("/", response_class=HTMLResponse)
async def index(request: Request):
    groq_available = bool(os.environ.get("GROQ_API_KEY_2", "").strip())
    gemini_available = bool(os.environ.get("GEMINI_API_KEY", "").strip())
    return templates.TemplateResponse(
        request=request,
        name="index.html",
        context={
            "groq_available": groq_available,
            "gemini_available": gemini_available
        }
    )



@app.post("/generate-subtitles")
async def generate_subtitles(
    video_file: UploadFile = File(...),
    target_lang: str = Form(...),
    provider: str = Form("google"),
):
    # Save uploaded video
    base_name = os.path.splitext(video_file.filename)[0]
    safe_name = "".join([c for c in base_name if c.isalnum() or c in " ._-"]).strip()
    file_id = safe_name if safe_name else "video"
    
    ext = os.path.splitext(video_file.filename)[1]
    version = time.strftime("%I-%M-%p--%d-%m-%Y")
    
    upload_dir = f"app/uploads/{version}"
    subtitles_dir = f"app/subtitles/{version}"
    os.makedirs(upload_dir, exist_ok=True)
    os.makedirs(subtitles_dir, exist_ok=True)
    
    video_path = f"{upload_dir}/{file_id}{ext}"
    audio_path = f"{upload_dir}/{file_id}.wav"
    
    with open(video_path, "wb") as buffer:
        shutil.copyfileobj(video_file.file, buffer)
        
    # Extract audio
    extract_audio(video_path, audio_path)
    
    # Transcribe audio to get segments (with phonetic bias)
    segments, info = transcribe_audio(audio_path, initial_prompt=WHISPER_PROMPT)
    
    # Correct English transcription errors (brands/names)
    apply_precision_patch(segments)
    
    # Generate English SRT
    en_srt_path = f"{subtitles_dir}/{file_id}_en.srt"
    save_srt(segments, en_srt_path)
    
    translator = get_translator(provider)
    target_srt_path = f"{subtitles_dir}/{file_id}_{target_lang}.srt"
    translate_srt(
        en_srt_path, 
        target_srt_path, 
        target_lang, 
        translator, 
        validate=True,
        glossary=PROJECT_GLOSSARY
    )
    
    # Clean up large video and audio files to save space
    if os.path.exists(video_path):
        os.remove(video_path)
    if os.path.exists(audio_path):
        os.remove(audio_path)
        
    return {
        "english_srt": f"/download/{version}/{file_id}_en.srt",
        "translated_srt": f"/download/{version}/{file_id}_{target_lang}.srt",
        "message": "Subtitles generated successfully!"
    }

@app.get("/download/{version_dir}/{filename}")
async def download_file(version_dir: str, filename: str):
    file_path = f"app/subtitles/{version_dir}/{filename}"
    return FileResponse(file_path, filename=filename)