"""
Download pipeline that abstracts the complete download → verify → tag → track process.
"""

import subprocess
from pathlib import Path
from typing import Any, Dict, List, Optional, Tuple, Union
from karaoke_downloader.config_manager import AppConfig

from karaoke_downloader.error_utils import (
    handle_file_validation_error,
    handle_yt_dlp_error,
    log_error,
)
from karaoke_downloader.id3_utils import add_id3_tags
from karaoke_downloader.songlist_manager import mark_songlist_song_downloaded
from karaoke_downloader.video_downloader import is_valid_mp4, sanitize_filename
from karaoke_downloader.youtube_utils import (
    build_yt_dlp_command,
    execute_yt_dlp_command,
    show_available_formats,
)
from karaoke_downloader.file_utils import (
    cleanup_temp_files,
    get_unique_filename,
    is_valid_mp4_file,
    sanitize_filename,
)


class DownloadPipeline:
    """
    Handles the complete download pipeline: download → verify → tag → track
    """

    def __init__(
        self,
        yt_dlp_path: str,
        config: Union[AppConfig, Dict[str, Any]],
        downloads_dir: Path,
        songlist_tracking: Optional[Dict] = None,
        tracker=None,
    ):
        self.yt_dlp_path = yt_dlp_path
        self.config = config
        self.downloads_dir = downloads_dir
        self.songlist_tracking = songlist_tracking or {}
        self.tracker = tracker

    def execute_pipeline(
        self,
        video_id: str,
        artist: str,
        title: str,
        channel_name: str,
        video_title: Optional[str] = None,
    ) -> bool:
        """
        Execute the complete download pipeline for a single video.

        Args:
            video_id: YouTube video ID
            artist: Artist name
            title: Song title
            channel_name: Channel name
            video_title: Original video title (optional)

        Returns:
            True if successful, False otherwise
        """
        try:
            # Step 1: Prepare file path and check for existing files
            output_path, file_exists = get_unique_filename(self.downloads_dir, channel_name, artist, title)
            
            if file_exists:
                print(f"⏭️  Skipping download - file already exists: {output_path.name}")
                # Still add tags and track the existing file
                if self._add_tags(output_path, artist, title, channel_name):
                    self._track_download(output_path, artist, title, video_id, channel_name)
                return True

            # Step 2: Download video
            if not self._download_video(video_id, output_path, artist, title, channel_name):
                return False

            # Step 3: Verify download
            if not self._verify_download(
                output_path, artist, title, video_id, channel_name
            ):
                return False

            # Step 4: Add ID3 tags
            if not self._add_tags(output_path, artist, title, channel_name):
                return False

            # Step 5: Track download
            if not self._track_download(
                output_path, artist, title, video_id, channel_name
            ):
                return False

            print(f"✅ Pipeline completed successfully: {artist} - {title}")
            return True

        except Exception as e:
            print(f"❌ Pipeline failed for {artist} - {title}: {e}")
            # Mark song as failed in tracking
            if self.tracker:
                self.tracker.mark_song_failed(
                    artist, title, video_id, channel_name, f"Pipeline failed: {e}"
                )
            return False

    def _download_video(
        self, video_id: str, output_path: Path, artist: str, title: str, channel_name: str
    ) -> bool:
        """Step 1: Download the video using yt-dlp."""
        output_path.parent.mkdir(parents=True, exist_ok=True)
        print(f"⬇️  Downloading: {artist} - {title} -> {output_path}")

        video_url = f"https://www.youtube.com/watch?v={video_id}"

        # Build command using centralized utility
        cmd = build_yt_dlp_command(
            self.yt_dlp_path, video_url, output_path, self.config
        )

        print(f"🔧 Running command: {' '.join(cmd)}")
        print(
            f"📺 Resolution settings: {self.config.download_settings.preferred_resolution}"
        )
        print(f"🎬 Format string: {self.config.download_settings.format}")

        # Debug: Show available formats (optional)
        if (
            hasattr(self.config, "debug_show_formats")
            and self.config.debug_show_formats
        ):
            show_available_formats(video_url, self.yt_dlp_path)

        try:
            result = execute_yt_dlp_command(cmd)
            print(f"✅ yt-dlp completed successfully")
            print(f"📄 yt-dlp stdout: {result.stdout}")
            return True

        except subprocess.CalledProcessError as e:
            error = handle_yt_dlp_error(e, artist, title, video_id)
            log_error(error)
            # Mark song as failed in tracking
            if self.tracker:
                self.tracker.mark_song_failed(
                    artist, title, video_id, channel_name, error.message
                )
            return False

    def _verify_download(
        self,
        output_path: Path,
        artist: str,
        title: str,
        video_id: str,
        channel_name: str,
    ) -> bool:
        """Step 2: Verify that the download was successful."""
        if not output_path.exists():
            print(f"❌ Download failed: file does not exist: {output_path}")
            # Check if yt-dlp saved it somewhere else
            possible_files = list(output_path.parent.glob("*.mp4"))
            if possible_files:
                print(
                    f"🔍 Found these files in the directory: {[f.name for f in possible_files]}"
                )
                # Look for a file that matches our pattern (artist - title)
                artist_part = artist.lower()
                title_part = title.lower()
                for file in possible_files:
                    file_lower = file.stem.lower()
                    if artist_part in file_lower and any(
                        word in file_lower for word in title_part.split()
                    ):
                        print(f"🎯 Found matching file: {file.name}")
                        output_path = file
                        break
                else:
                    print(f"❌ No matching file found for: {artist} - {title}")
                    # Mark song as failed in tracking
                    if self.tracker:
                        error_msg = f"Download failed: file does not exist and no matching file found"
                        self.tracker.mark_song_failed(
                            artist, title, video_id, channel_name, error_msg
                        )
                    return False
            else:
                # Mark song as failed in tracking
                if self.tracker:
                    error_msg = f"Download failed: file does not exist"
                    self.tracker.mark_song_failed(
                        artist, title, video_id, channel_name, error_msg
                    )
                return False

        # Validate file
        if not is_valid_mp4(output_path):
            error = handle_file_validation_error(
                "File is not a valid MP4",
                output_path,
                artist,
                title,
                video_id,
                channel_name,
            )
            log_error(error)
            # Mark song as failed in tracking
            if self.tracker:
                self.tracker.mark_song_failed(
                    artist, title, video_id, channel_name, error.message
                )
            return False

        print(f"✅ Download verified: {output_path}")
        return True

    def _add_tags(
        self, output_path: Path, artist: str, title: str, channel_name: str
    ) -> bool:
        """Step 3: Add ID3 tags to the downloaded file."""
        try:
            # Use the same artist/title as the filename for consistency
            # Don't add "(Karaoke Version)" to the ID3 tag title
            add_id3_tags(
                output_path, f"{artist} - {title}", channel_name
            )
            print(f"🏷️  Added ID3 tags: {artist} - {title}")
            return True
        except Exception as e:
            print(f"⚠️  Failed to add ID3 tags: {e}")
            # Don't fail the pipeline for tag issues
            return True

    def _track_download(
        self,
        output_path: Path,
        artist: str,
        title: str,
        video_id: str,
        channel_name: str,
    ) -> bool:
        """Step 4: Track the download in the tracking system."""
        try:
            # Track in songlist if available
            if self.songlist_tracking is not None:
                mark_songlist_song_downloaded(
                    self.songlist_tracking, artist, title, channel_name, output_path
                )

            # Track in main tracking system if available
            if self.tracker is not None:
                file_size = output_path.stat().st_size if output_path.exists() else None
                self.tracker.mark_song_downloaded(
                    artist, title, video_id, channel_name, output_path, file_size
                )

            print(f"📊 Tracked download: {artist} - {title}")
            return True

        except Exception as e:
            print(f"⚠️  Failed to track download: {e}")
            # Don't fail the pipeline for tracking issues
            return True

    def batch_execute(
        self,
        videos: List[Dict[str, Any]],
        channel_name: str,
        limit: Optional[int] = None,
    ) -> Tuple[int, int]:
        """
        Execute the pipeline for multiple videos.

        Args:
            videos: List of video dictionaries with 'id', 'title', etc.
            channel_name: Channel name
            limit: Optional limit on number of videos to process

        Returns:
            Tuple of (successful_downloads, total_attempted)
        """
        if limit:
            videos = videos[:limit]

        successful = 0
        total = len(videos)

        for i, video in enumerate(videos, 1):
            video_id = video["id"]
            video_title = video.get("title", "")

            # Extract artist and title from video title
            from karaoke_downloader.channel_parser import ChannelParser

            channel_parser = ChannelParser()
            artist, title = channel_parser.extract_artist_title(video_title, channel_name)

            print(f"   ({i}/{total}) Processing: {artist} - {title}")

            if self.execute_pipeline(
                video_id, artist, title, channel_name, video_title
            ):
                successful += 1
            else:
                print(f"   ❌ Failed to process: {artist} - {title}")

        return successful, total