from fastapi import FastAPI, UploadFile, File, Form
from fastapi.responses import JSONResponse, FileResponse
from fastapi.middleware.cors import CORSMiddleware

import os
import uuid
import shutil
import subprocess
import threading
import time

# =========================================
# FASTAPI APP
# =========================================

app = FastAPI()

# =========================================
# CORS
# =========================================

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

# =========================================
# FOLDERS
# =========================================

UPLOAD_DIR = "uploads"
OUTPUT_DIR = "outputs"

os.makedirs(UPLOAD_DIR, exist_ok=True)
os.makedirs(OUTPUT_DIR, exist_ok=True)

# =========================================
# TASK STORE
# =========================================

tasks = {}

# =========================================
# GET VIDEO DURATION
# =========================================

def get_video_duration(filepath):

    command = [
        "ffprobe",
        "-v",
        "error",
        "-show_entries",
        "format=duration",
        "-of",
        "default=noprint_wrappers=1:nokey=1",
        filepath
    ]

    result = subprocess.run(
        command,
        stdout=subprocess.PIPE,
        stderr=subprocess.PIPE,
        text=True
    )

    try:
        return float(result.stdout.strip())
    except:
        return 0

# =========================================
# COMPRESS VIDEO WORKER
# =========================================

def compress_worker(
    task_id,
    input_path,
    output_path,
    target_size_mb
):

    try:

        # =====================================
        # GET DURATION
        # =====================================

        duration = get_video_duration(
            input_path
        )

        if duration <= 0:

            tasks[task_id] = {
                "status": "error",
                "progress": 0,
                "message": "Invalid video"
            }

            return

        # =====================================
        # BITRATE CALCULATION
        # =====================================

        # Convert MB -> bits
        total_bits = (
            target_size_mb
            * 1024
            * 1024
            * 8
        )

        # Audio bitrate
        audio_bitrate = 96

        # Calculate total bitrate
        total_bitrate = int(
            total_bits / duration / 1000
        )

        # Video bitrate
        video_bitrate = (
            total_bitrate - audio_bitrate
        )

        # Minimum safe bitrate
        if video_bitrate < 250:
            video_bitrate = 250

        # =====================================
        # UPDATE STATUS
        # =====================================

        tasks[task_id] = {
            "status": "processing",
            "progress": 0
        }

        # =====================================
        # FFMPEG COMMAND
        # =====================================

        command = [

            "ffmpeg",

            "-i",
            input_path,

            # VIDEO CODEC
            "-vcodec",
            "libx264",

            # FAST PRESET
            "-preset",
            "veryfast",

            # VIDEO BITRATE
            "-b:v",
            f"{video_bitrate}k",

            "-maxrate",
            f"{video_bitrate}k",

            "-bufsize",
            f"{video_bitrate * 2}k",

            # AUDIO
            "-acodec",
            "aac",

            "-b:a",
            f"{audio_bitrate}k",

            # WEB OPTIMIZATION
            "-movflags",
            "+faststart",

            # MULTI THREAD
            "-threads",
            "0",

            # PROGRESS
            "-progress",
            "pipe:1",

            # OVERWRITE
            "-y",

            output_path
        ]

        process = subprocess.Popen(
            command,
            stdout=subprocess.PIPE,
            stderr=subprocess.STDOUT,
            text=True,
            universal_newlines=True
        )

        # =====================================
        # REAL PROGRESS
        # =====================================

        while True:

            line = process.stdout.readline()

            if not line:
                break

            line = line.strip()

            if "out_time_ms=" in line:

                try:

                    out_time_ms = int(
                        line.split("=")[1]
                    )

                    current_time = (
                        out_time_ms / 1000000
                    )

                    percent = int(
                        (current_time / duration)
                        * 100
                    )

                    if percent > 100:
                        percent = 100

                    tasks[task_id] = {
                        "status": "processing",
                        "progress": percent
                    }

                except:
                    pass

        process.wait()

        # =====================================
        # CHECK RESULT
        # =====================================

        if process.returncode != 0:

            tasks[task_id] = {
                "status": "error",
                "progress": 0,
                "message": "Compression failed"
            }

            return

        if not os.path.exists(output_path):

            tasks[task_id] = {
                "status": "error",
                "progress": 0,
                "message": "Output file missing"
            }

            return

        # =====================================
        # FINAL SIZE CHECK
        # =====================================

        output_size_mb = (
            os.path.getsize(output_path)
            / 1024
            / 1024
        )

        # =====================================
        # COMPLETE
        # =====================================

        tasks[task_id] = {
            "status": "completed",
            "progress": 100,
            "download_url":
            f"/download/{task_id}",
            "output_size_mb":
            round(output_size_mb, 2)
        }

    except Exception as e:

        tasks[task_id] = {
            "status": "error",
            "progress": 0,
            "message": str(e)
        }

# =========================================
# COMPRESS API
# =========================================

@app.post("/compress")
async def compress_video(
    file: UploadFile = File(...),
    target_size: int = Form(...)
):

    try:

        if not file.filename:

            return JSONResponse(
                {"error": "No file uploaded"},
                status_code=400
            )

        # =====================================
        # TASK ID
        # =====================================

        task_id = str(uuid.uuid4())

        input_path = os.path.join(
            UPLOAD_DIR,
            f"{task_id}_{file.filename}"
        )

        output_path = os.path.join(
            OUTPUT_DIR,
            f"{task_id}.mp4"
        )

        # =====================================
        # SAVE FILE
        # =====================================

        with open(input_path, "wb") as buffer:

            shutil.copyfileobj(
                file.file,
                buffer
            )

        # =====================================
        # START THREAD
        # =====================================

        thread = threading.Thread(
            target=compress_worker,
            args=(
                task_id,
                input_path,
                output_path,
                target_size
            )
        )

        thread.start()

        return {
            "success": True,
            "task_id": task_id
        }

    except Exception as e:

        return JSONResponse(
            {"error": str(e)},
            status_code=500
        )

# =========================================
# PROGRESS API
# =========================================

@app.get("/progress/{task_id}")
async def get_progress(task_id: str):

    if task_id not in tasks:

        return JSONResponse(
            {"error": "Task not found"},
            status_code=404
        )

    return tasks[task_id]

# =========================================
# DOWNLOAD API
# =========================================

@app.get("/download/{task_id}")
async def download_video(task_id: str):

    filepath = os.path.join(
        OUTPUT_DIR,
        f"{task_id}.mp4"
    )

    if not os.path.exists(filepath):

        return JSONResponse(
            {"error": "File not found"},
            status_code=404
        )

    return FileResponse(
        filepath,
        media_type="video/mp4",
        filename="compressed-video.mp4"
    )

# =========================================
# AUTO CLEANUP
# =========================================

def cleanup_old_files():

    while True:

        now = time.time()

        for folder in [
            UPLOAD_DIR,
            OUTPUT_DIR
        ]:

            for filename in os.listdir(folder):

                filepath = os.path.join(
                    folder,
                    filename
                )

                try:

                    age = (
                        now -
                        os.path.getmtime(filepath)
                    )

                    # Delete after 1 hour
                    if age > 3600:

                        os.remove(filepath)

                except:
                    pass

        time.sleep(1800)

cleanup_thread = threading.Thread(
    target=cleanup_old_files,
    daemon=True
)

cleanup_thread.start()

# =========================================
# ROOT
# =========================================

@app.get("/")
async def home():

    return {
        "message":
        "Video Compressor API Running"
    }

# =========================================
# RUN APP
# =========================================

if __name__ == "__main__":

    import uvicorn

    port = int(
        os.environ.get("PORT", 7860)
    )

    uvicorn.run(
        "app:app",
        host="0.0.0.0",
        port=port
    )