import os
import subprocess
import concurrent.futures
import shutil
from typing import List, Optional
from fastapi import FastAPI, HTTPException
from fastapi.middleware.cors import CORSMiddleware
from pydantic import BaseModel
import cloudinary
import cloudinary.uploader

# ------------------------------------------
# CONFIGURATION
# ------------------------------------------
# NOTE: In a real production app, use Environment Variables!
CLOUD_NAME = "dgfhhszx8"
UPLOAD_PRESET = "testing"

# ------------------------------------------
# APP SETUP
# ------------------------------------------
app = FastAPI()

app.add_middleware(
    CORSMiddleware,
    allow_origins=["*"],
    allow_credentials=True,
    allow_methods=["*"],
    allow_headers=["*"],
)

class VideoRequest(BaseModel):
    video_url: str

class VideoResponse(BaseModel):
    status: str
    message: str
    uploaded_chunks: Optional[List[str]] = None

# ------------------------------------------
# HELPER FUNCTIONS
# ------------------------------------------
def process_video_task(video_url: str):
    """
    Downloads, Splits, and Uploads the video.
    Returns list of Cloudinary URLs.
    """
    # Use /tmp for writable storage in Docker
    work_dir = "/tmp/data"
    os.makedirs(work_dir, exist_ok=True)
    
    filename = os.path.join(work_dir, "temp_video.mp4")
    
    print(f"\n[JOB START] Processing: {video_url}")
    
    # Clean previous run if needed
    if os.path.exists(filename): 
        os.remove(filename)
    
    # A. DOWNLOAD (using wget)
    ret = os.system(f'wget -O {filename} "{video_url}" -q')
    if ret != 0 or not os.path.exists(filename) or os.path.getsize(filename) < 1000:
        print("❌ Download failed.")
        return []

    # B. SPLIT
    CHUNK_LIMIT_MB = 95
    TARGET_BYTES = CHUNK_LIMIT_MB * 1024 * 1024
    
    # Get Duration
    try:
        cmd = f"ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 {filename}"
        dur_out = subprocess.check_output(cmd, shell=True).decode().strip()
        total_duration = float(dur_out)
    except Exception as e:
        print(f"❌ Failed to get duration: {e}")
        return []

    file_size = os.path.getsize(filename)
    avg_bytes_per_sec = file_size / total_duration
    
    parts = []
    current_start = 0.0
    chunk_idx = 0
    
    while current_start < total_duration:
        est_duration = TARGET_BYTES / avg_bytes_per_sec
        success = False
        while not success:
            current_end = current_start + est_duration
            if current_end > total_duration: current_end = total_duration
            
            chunk_name = os.path.join(work_dir, f"part_{chunk_idx:03d}.mp4")
            
            # Cut command
            cmd = f"ffmpeg -y -hide_banner -loglevel error -ss {current_start} -to {current_end} -i {filename} -c copy -avoid_negative_ts make_zero {chunk_name}"
            subprocess.run(cmd, shell=True)
            
            if not os.path.exists(chunk_name):
                # End of file case or error, assume done for this chunking loop logic if EOF
                success = True 
                break

            chunk_size = os.path.getsize(chunk_name)
            chunk_size_mb = chunk_size / (1024*1024)
            
            if chunk_size_mb > 99.0:
                est_duration = est_duration * 0.9
                os.remove(chunk_name)
            else:
                parts.append(chunk_name)
                current_start = current_end
                chunk_idx += 1
                success = True

    print(f"✅ Split into {len(parts)} chunks.")

    # C. UPLOAD (Parallel)
    uploaded_urls = []
    
    def upload_chunk_worker(part_file):
        try:
            # Unsigned upload
            response = cloudinary.uploader.unsigned_upload(
                part_file,
                UPLOAD_PRESET,
                cloud_name=CLOUD_NAME,
                resource_type="video"
            )
            url = response['secure_url']
            # Clean up immediately
            if os.path.exists(part_file):
                os.remove(part_file)
            return url
        except Exception as e:
            print(f"❌ Upload failed for {part_file}: {e}")
            return None

    # Use ThreadPool to upload concurrently
    # Note: Cloudinary Python SDK is synchronous, so threads work well here
    # to release GIL during network I/O.
    # We sort mainly by part name to keep order, but the map results are ordered.
    with concurrent.futures.ThreadPoolExecutor(max_workers=4) as executor:
        results = executor.map(upload_chunk_worker, parts)
        for res in results:
            if res: uploaded_urls.append(res)
            
    # Cleanup main file
    if os.path.exists(filename): os.remove(filename)
    
    print(f"✅ [JOB DONE] Uploaded {len(uploaded_urls)} chunks.")
    return uploaded_urls

# ------------------------------------------
# ENDPOINTS
# ------------------------------------------
@app.post("/process-video", response_model=VideoResponse)
def process_video_endpoint(req: VideoRequest):
    """
    Synchronous processing endpoint.
    Hugging Face Spaces (CPU Basic) can handle this long request.
    Recommend upgrading to GPU/Pro if timeouts occur ( > 60s).
    """
    urls = process_video_task(req.video_url)
    
    if not urls:
        raise HTTPException(status_code=500, detail="Processing failed or produced 0 chunks")
    
    return VideoResponse(
        status="success",
        message="Video processed successfully",
        uploaded_chunks=urls
    )

@app.get("/")
def home():
    return {"message": "Hugging Face Video Processor is Running"}