import logging
import traceback
from threading import Thread
from dataclasses import dataclass
import yt_dlp
from typing import Callable, Optional, List, Dict, Any

# Import the get_logger function from your custom logger module
from downloaderyoutube.utils.logger import get_logger

# Get a logger instance for this module
logger = get_logger(__name__)

@dataclass
class VideoFormat:
    """A simple class to hold structured information about a video format."""
    format_id: str
    resolution: str
    ext: str
    filesize: Optional[int]
    note: str  # e.g., "Video Only", "Audio Only", "Progressive"

    def __str__(self) -> str:
        """User-friendly string representation for the combobox."""
        size_mb = f"{self.filesize / (1024 * 1024):.2f} MB" if self.filesize else "N/A"
        return f"{self.resolution} ({self.ext}) - {size_mb} - {self.note}"


class Downloader:
    """
    Handles video operations using yt-dlp in separate threads to avoid
    blocking the GUI.
    """

    def __init__(self):
        self.progress_callback: Optional[Callable[[int], None]] = None
        self.completion_callback: Optional[Callable[[Optional[str]], None]] = None
        self.formats_callback: Optional[Callable[[Optional[Dict[str, Any]], Optional[List[VideoFormat]]], None]] = None

    def _progress_hook(self, d: Dict[str, Any]):
        if d["status"] == "downloading":
            if d.get("total_bytes") and d.get("downloaded_bytes"):
                percentage = (d["downloaded_bytes"] / d["total_bytes"]) * 100
                if self.progress_callback:
                    self.progress_callback(int(percentage))
        elif d["status"] == "finished":
            logger.info("yt-dlp finished downloading.")

    def _get_formats_task(self, url: str):
        """Task to fetch video formats and info in a thread."""
        try:
            logger.info(f"Fetching formats for URL: {url}")
            ydl_opts = {"noplaylist": True}
            with yt_dlp.YoutubeDL(ydl_opts) as ydl:
                info = ydl.extract_info(url, download=False)
            
            video_info = {
                "title": info.get("title", "N/A"),
                "uploader": info.get("uploader", "N/A"),
                "duration_string": info.get("duration_string", "N/A"),
            }

            formats = []
            for f in info.get("formats", []):
                if f.get("vcodec", "none") != "none" and f.get("ext") == "mp4":
                    note = "Progressive" if f.get("acodec", "none") != "none" else "Video Only"
                    formats.append(VideoFormat(
                        format_id=f["format_id"],
                        resolution=f.get("format_note", f.get("resolution", "N/A")),
                        ext=f["ext"],
                        filesize=f.get("filesize"),
                        note=note
                    ))
            
            formats.sort(key=lambda x: (x.note != "Progressive", -int(x.resolution.replace("p", "")) if x.resolution.replace("p", "").isdigit() else 0))

            logger.info(f"Found {len(formats)} suitable formats.")
            if self.formats_callback:
                self.formats_callback(video_info, formats)

        except Exception as e:
            error_message = f"Failed to fetch formats: {e}"
            logger.error(error_message)
            logger.debug(traceback.format_exc())
            if self.formats_callback:
                self.formats_callback(None, None) # Indicate failure

    def get_video_formats(self, url: str, formats_callback: Callable[[Optional[Dict[str, Any]], Optional[List[VideoFormat]]], None]):
        """Starts the format fetching process in a new thread."""
        self.formats_callback = formats_callback
        thread = Thread(target=self._get_formats_task, args=(url,), daemon=True)
        thread.start()

    def _download_task(self, url: str, download_path: str, format_id: str):
        """The actual download logic that runs in a separate thread."""
        try:
            logger.info(f"Starting download for URL: {url} with format: {format_id}")
            ydl_opts = {
                "format": format_id,
                "outtmpl": f"{download_path}/%(title)s.%(ext)s",
                "progress_hooks": [self._progress_hook],
                "logger": logger,
                "noplaylist": True,
            }

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

            logger.info(f"Successfully downloaded video from URL: {url}")
            if self.completion_callback:
                self.completion_callback(None)

        except Exception as e:
            error_message = f"An unexpected error occurred: {e}"
            logger.error(error_message)
            logger.debug(traceback.format_exc())
            if self.completion_callback:
                self.completion_callback(error_message)

    def download_video(
        self,
        url: str,
        download_path: str,
        format_id: str,
        progress_callback: Callable[[int], None],
        completion_callback: Callable[[Optional[str]], None],
    ):
        """Starts the video download in a new thread."""
        self.progress_callback = progress_callback
        self.completion_callback = completion_callback
        thread = Thread(
            target=self._download_task, args=(url, download_path, format_id), daemon=True
        )
        thread.start()