import asyncio
import json
import os
import re
import uuid
from pathlib import Path
from typing import Optional

from fastapi import FastAPI, HTTPException
from fastapi.responses import FileResponse, StreamingResponse
from fastapi.staticfiles import StaticFiles
from pydantic import BaseModel
import yt_dlp

DOWNLOAD_DIR = Path(os.environ.get("DOWNLOAD_DIR", "/downloads"))
DOWNLOAD_DIR.mkdir(parents=True, exist_ok=True)

app = FastAPI(title="yt-dlp Web Downloader")

# In-memory job store
jobs: dict[str, dict] = {}


class DownloadRequest(BaseModel):
    url: str
    format: str = "video"  # "video" | "audio"
    quality: str = "best"  # "best" | "1080" | "720" | "480" | "360"


class JobStatus(BaseModel):
    id: str
    status: str  # "pending" | "running" | "done" | "error"
    progress: float = 0.0
    speed: str = ""
    eta: str = ""
    filename: str = ""
    error: str = ""
    title: str = ""


def make_progress_hook(job_id: str):
    def hook(d):
        job = jobs.get(job_id)
        if not job:
            return
        if d["status"] == "downloading":
            raw = d.get("_percent_str", "0%").strip().replace("%", "")
            try:
                job["progress"] = float(raw)
            except ValueError:
                job["progress"] = 0.0
            job["speed"] = d.get("_speed_str", "").strip()
            job["eta"] = d.get("_eta_str", "").strip()
            job["status"] = "running"
        elif d["status"] == "finished":
            job["progress"] = 100.0
            job["status"] = "processing"
    return hook


def build_ydl_opts(req: DownloadRequest, job_id: str, out_template: str) -> dict:
    opts = {
        "outtmpl": out_template,
        "progress_hooks": [make_progress_hook(job_id)],
        "quiet": True,
        "no_warnings": True,
        "noplaylist": True,
    }

    if req.format == "audio":
        opts["format"] = "bestaudio/best"
        opts["postprocessors"] = [
            {
                "key": "FFmpegExtractAudio",
                "preferredcodec": "mp3",
                "preferredquality": "192",
            }
        ]
    else:
        # Video quality mapping
        quality_map = {
            "best": "bestvideo[ext=mp4]+bestaudio[ext=m4a]/bestvideo+bestaudio/best",
            "1080": "bestvideo[height<=1080][ext=mp4]+bestaudio[ext=m4a]/bestvideo[height<=1080]+bestaudio/best[height<=1080]",
            "720": "bestvideo[height<=720][ext=mp4]+bestaudio[ext=m4a]/bestvideo[height<=720]+bestaudio/best[height<=720]",
            "480": "bestvideo[height<=480][ext=mp4]+bestaudio[ext=m4a]/bestvideo[height<=480]+bestaudio/best[height<=480]",
            "360": "bestvideo[height<=360][ext=mp4]+bestaudio[ext=m4a]/bestvideo[height<=360]+bestaudio/best[height<=360]",
        }
        opts["format"] = quality_map.get(req.quality, quality_map["best"])
        opts["merge_output_format"] = "mp4"

    return opts


def run_download(job_id: str, req: DownloadRequest):
    job = jobs[job_id]
    try:
        out_template = str(DOWNLOAD_DIR / f"{job_id}_%(title)s.%(ext)s")
        opts = build_ydl_opts(req, job_id, out_template)

        # First fetch info to get title
        with yt_dlp.YoutubeDL({"quiet": True, "no_warnings": True}) as ydl_info:
            info = ydl_info.extract_info(req.url, download=False)
            job["title"] = info.get("title", "Unknown")

        with yt_dlp.YoutubeDL(opts) as ydl:
            ydl.download([req.url])

        # Find the output file
        found = list(DOWNLOAD_DIR.glob(f"{job_id}_*"))
        if found:
            job["filename"] = found[0].name
            job["status"] = "done"
            job["progress"] = 100.0
        else:
            job["status"] = "error"
            job["error"] = "Output file not found after download."
    except Exception as e:
        job["status"] = "error"
        job["error"] = str(e)


@app.post("/api/download", response_model=JobStatus)
async def start_download(req: DownloadRequest):
    job_id = str(uuid.uuid4())
    jobs[job_id] = {
        "id": job_id,
        "status": "pending",
        "progress": 0.0,
        "speed": "",
        "eta": "",
        "filename": "",
        "error": "",
        "title": "",
    }
    loop = asyncio.get_event_loop()
    loop.run_in_executor(None, run_download, job_id, req)
    return JobStatus(id=job_id, status="pending")


@app.get("/api/status/{job_id}", response_model=JobStatus)
async def get_status(job_id: str):
    job = jobs.get(job_id)
    if not job:
        raise HTTPException(status_code=404, detail="Job not found")
    return JobStatus(**job)


@app.get("/api/file/{job_id}")
async def download_file(job_id: str):
    job = jobs.get(job_id)
    if not job:
        raise HTTPException(status_code=404, detail="Job not found")
    if job["status"] != "done":
        raise HTTPException(status_code=400, detail="File not ready")
    file_path = DOWNLOAD_DIR / job["filename"]
    if not file_path.exists():
        raise HTTPException(status_code=404, detail="File missing on disk")
    return FileResponse(
        path=str(file_path),
        filename=job["filename"].split("_", 1)[-1] if "_" in job["filename"] else job["filename"],
        media_type="application/octet-stream",
    )


@app.get("/api/info")
async def get_info(url: str):
    try:
        with yt_dlp.YoutubeDL({"quiet": True, "no_warnings": True}) as ydl:
            info = ydl.extract_info(url, download=False)
        return {
            "title": info.get("title", ""),
            "thumbnail": info.get("thumbnail", ""),
            "duration": info.get("duration", 0),
            "uploader": info.get("uploader", ""),
            "view_count": info.get("view_count", 0),
        }
    except Exception as e:
        raise HTTPException(status_code=400, detail=str(e))


# Serve static frontend — resolve relative to this file so it works both locally and in Docker
STATIC_DIR = Path(__file__).parent / "static"
app.mount("/", StaticFiles(directory=str(STATIC_DIR), html=True), name="static")