import os
import shutil
import subprocess
import tempfile
from fastapi import FastAPI, File, UploadFile, Form, HTTPException, BackgroundTasks
from fastapi.responses import FileResponse, RedirectResponse
from fastapi.middleware.cors import CORSMiddleware

app = FastAPI()

# Add CORS middleware (adjust allow_origins for production)
app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

# Ensure the base temporary directory exists.
TEMP_DIR = "temp_files"
os.makedirs(TEMP_DIR, exist_ok=True)

@app.get("/")
def read_root():
    return {"message": "Video Subtitle Server is running"}

@app.post("/burn-subtitles")
async def burn_subtitles(
    background_tasks: BackgroundTasks,
    video: UploadFile = File(...),
    subtitle: UploadFile = File(...),
    font_size: str = Form("20"),
    font_color: str = Form("white"),
    output_format: str = Form("mp4")
):
    # Create a unique temporary directory for this job.
    job_dir = tempfile.mkdtemp(prefix='job_', dir=TEMP_DIR)
    
    try:
        # Build file paths.
        video_path = os.path.join(job_dir, f"input{os.path.splitext(video.filename)[1]}")
        subtitle_path = os.path.join(job_dir, "subtitles.srt")
        output_path = os.path.join(job_dir, f"output.{output_format}")
        
        # Save uploaded video file.
        with open(video_path, "wb") as video_file:
            shutil.copyfileobj(video.file, video_file)
        
        # Save uploaded subtitle file.
        with open(subtitle_path, "wb") as subtitle_file:
            shutil.copyfileobj(subtitle.file, subtitle_file)
        
        # Format the font color for FFmpeg if provided as hex.
        if font_color.startswith('#'):
            font_color = font_color.lstrip('#')
            if len(font_color) == 6:
                r, g, b = font_color[0:2], font_color[2:4], font_color[4:6]
                font_color = f"&H{b}{g}{r}&"
        
        # Build the subtitle style string.
        subtitle_style = f"FontSize={font_size},PrimaryColour={font_color}"
        command = [
            "ffmpeg",
            "-i", video_path,
            "-vf", f"subtitles={subtitle_path}:force_style='{subtitle_style}'",
            "-c:a", "copy",
            output_path
        ]
        
        # Run the FFmpeg command.
        process = subprocess.run(command, capture_output=True, text=True)
        if process.returncode != 0:
            raise HTTPException(status_code=500, detail=f"FFmpeg Error: {process.stderr}")
        
        # Schedule cleanup of the job directory after the response is sent.
        background_tasks.add_task(shutil.rmtree, job_dir)
        
        return FileResponse(
            output_path, 
            media_type=f"video/{output_format}",
            filename=f"processed_video.{output_format}"
        )
    
    except Exception as e:
        # Clean up immediately on error.
        shutil.rmtree(job_dir, ignore_errors=True)
        raise HTTPException(status_code=500, detail=str(e))

@app.post("/convert-srt")
async def convert_srt(
    background_tasks: BackgroundTasks,
    subtitle: UploadFile = File(...),
):
    job_dir = tempfile.mkdtemp(prefix='job_', dir=TEMP_DIR)
    
    try:
        subtitle_path = os.path.join(job_dir, "subtitles.srt")
        with open(subtitle_path, "wb") as subtitle_file:
            shutil.copyfileobj(subtitle.file, subtitle_file)
        
        background_tasks.add_task(shutil.rmtree, job_dir)
        return FileResponse(
            subtitle_path, 
            media_type="text/plain",
            filename="subtitles.srt"
        )
    
    except Exception as e:
        shutil.rmtree(job_dir, ignore_errors=True)
        raise HTTPException(status_code=500, detail=str(e))

@app.get("/health")
def health_check():
    return {"status": "healthy"}

@app.get("/doc")
def redirect_to_docs():
    return RedirectResponse(url="/docs")