"""
Monochrome API integration for Votify Web.

Orchestrates the Spotify URL → Tidal ID → download pipeline
for use from app.py background threads.
"""

import os
import shutil
import time
from pathlib import Path

from monochrome import discover_instances
from monochrome.spotify_to_ids import (
    parse_spotify_url,
    fetch_spotify_embed,
    extract_collection_name,
    extract_tracks,
    search_monochrome,
    find_best_match,
    similarity,
    normalize,
)
from monochrome.download import (
    get_stream_url_tidal,
    get_stream_url_qobuz,
    download_file,
    fetch_cover_art,
    embed_metadata,
    convert_to_mp3,
)
from utils import sanitize_filename, rename_from_metadata


def verify_match(spotify_track, tidal_info, search_match, log):
    """Cross-reference Spotify metadata against Tidal track data.
    Falls back to search_match fields when tidal_info has empty values.
    Returns True if the track is a valid match."""
    sp_title = spotify_track.get("title", "")

    # Prefer tidal_info title, fall back to search match title
    ti_title = tidal_info.get("title", "") if tidal_info else ""
    if not ti_title:
        ti_title = search_match.get("title", "") if search_match else ""
    if sp_title and ti_title:
        title_sim = similarity(sp_title, ti_title)
        if title_sim < 0.5:
            log(f"[monochrome] Title mismatch: '{sp_title}' vs '{ti_title}' (sim={title_sim:.2f})")
            return False

    sp_artist = spotify_track.get("artist", "")

    # Prefer tidal_info artist, fall back to search match artist
    ti_artist = ""
    for src in (tidal_info, search_match):
        if not src:
            continue
        artist_obj = src.get("artist", {})
        ti_artist = artist_obj.get("name", "") if isinstance(artist_obj, dict) else str(artist_obj)
        if ti_artist:
            break
    if sp_artist and ti_artist:
        artist_sim = similarity(sp_artist, ti_artist)
        # For multi-artist tracks, Tidal may only return the primary artist.
        # Check if Tidal artist tokens are a subset of Spotify artist tokens.
        sp_tokens = set(normalize(sp_artist).split())
        ti_tokens = set(normalize(ti_artist).split())
        is_subset = ti_tokens and ti_tokens.issubset(sp_tokens)
        if artist_sim < 0.4 and not is_subset:
            log(f"[monochrome] Artist mismatch: '{sp_artist}' vs '{ti_artist}' (sim={artist_sim:.2f})")
            return False

    # Duration check (strongest signal)
    sp_dur = spotify_track.get("duration")  # milliseconds
    ti_dur = (tidal_info or {}).get("duration")  # seconds
    if sp_dur and ti_dur:
        sp_seconds = sp_dur / 1000
        if abs(sp_seconds - ti_dur) > 5:
            log(f"[monochrome] Duration mismatch: {sp_seconds:.0f}s vs {ti_dur}s")
            return False

    return True


def download_spotify_url(spotify_url, quality, output_dir, log=None, cancel_check=None):
    """Download tracks from a Spotify URL via Monochrome.

    Args:
        spotify_url: Spotify track/album/playlist URL
        quality: One of HI_RES_LOSSLESS, LOSSLESS, HIGH, LOW, MP3_320
        output_dir: Directory to save downloaded files
        log: Callback (str) -> None for progress messages
        cancel_check: Callback () -> bool, returns True if cancelled

    Returns:
        (success_count, total_tracks, fail_info) where fail_info is:
        {"failed_urls": [...], "subfolder": "name" or None}
    """
    if log is None:
        log = print
    if cancel_check is None:
        cancel_check = lambda: False

    want_mp3 = quality == "MP3_320"
    api_quality = "LOSSLESS" if want_mp3 else quality

    # Step 1: Discover instances
    log("[monochrome] Discovering API instances...")
    instances = discover_instances(log=log)

    # Step 2: Parse Spotify URL
    fail_info = {"failed_urls": [], "subfolder": None}

    sp_type, sp_id = parse_spotify_url(spotify_url)
    if not sp_type:
        log(f"[monochrome] Invalid Spotify URL: {spotify_url}")
        return 0, 0, fail_info

    # Step 3: Fetch track list from Spotify
    log(f"[monochrome] Fetching Spotify {sp_type}: {sp_id}")
    embed_data = fetch_spotify_embed(sp_type, sp_id)
    tracks = extract_tracks(embed_data, sp_type, sp_id)

    if not tracks:
        log(f"[monochrome] Could not extract tracks from {spotify_url}")
        return 0, 0, fail_info

    total = len(tracks)
    log(f"[monochrome] Found {total} track(s) on Spotify")

    # Create subfolder for albums/playlists
    dl_dir = output_dir
    subfolder_name = None
    if total > 1:
        collection_name = extract_collection_name(embed_data, sp_type)
        if collection_name:
            subfolder_name = sanitize_filename(collection_name)
        else:
            subfolder_name = sanitize_filename(f"{sp_type}_{sp_id}")
        dl_dir = os.path.join(output_dir, subfolder_name)
        os.makedirs(dl_dir, exist_ok=True)
        log(f"[monochrome] Saving to folder: {subfolder_name}")
    fail_info["subfolder"] = subfolder_name

    success = 0
    failed_tracks = []
    failed_urls = []
    last_final_path = None

    for i, track in enumerate(tracks):
        if cancel_check():
            log("[monochrome] Cancelled")
            break

        query = f"{track['artist']} {track['title']}".strip()
        log(f"[monochrome] Track {i + 1}/{total}: {query}")

        # Search and match
        results = search_monochrome(instances, query, log=log)
        match, score = find_best_match(results, track["title"], track["artist"])

        if not match:
            log(f"[monochrome] No match found for: {query}")
            failed_tracks.append(query)
            sp_id = track.get("sp_id")
            if sp_id:
                failed_urls.append(f"https://open.spotify.com/track/{sp_id}")
            if i < total - 1:
                time.sleep(0.5)
            continue

        track_id = match.get("id")
        m_title = match.get("title", "?")
        m_artist_obj = match.get("artist", {})
        m_artist = m_artist_obj.get("name", "?") if isinstance(m_artist_obj, dict) else str(m_artist_obj)
        log(f"[monochrome] Matched: {m_artist} - {m_title} (score: {score:.2f})")

        # Get stream URL
        stream_url, track_data = get_stream_url_tidal(instances, track_id, api_quality, log=log)

        if not stream_url:
            log("[monochrome] Tidal failed, trying Qobuz...")
            stream_url = get_stream_url_qobuz(track_id, api_quality, log=log)

        if not stream_url:
            log(f"[monochrome] Failed to get stream for: {query}")
            failed_tracks.append(query)
            sp_id = track.get("sp_id")
            if sp_id:
                failed_urls.append(f"https://open.spotify.com/track/{sp_id}")
            if i < total - 1:
                time.sleep(0.5)
            continue

        # Build metadata from match info
        info = match
        if track_data and isinstance(track_data, dict):
            # Merge: track_data may have more detail
            for k, v in track_data.items():
                if k not in info or not info[k]:
                    info[k] = v

        # Verify match against Spotify metadata
        if not verify_match(track, track_data, match, log):
            failed_tracks.append(query)
            sp_id = track.get("sp_id")
            if sp_id:
                failed_urls.append(f"https://open.spotify.com/track/{sp_id}")
            if i < total - 1:
                time.sleep(0.5)
            continue

        # Determine file extension and path (temp name until metadata rename)
        if want_mp3:
            ext = ".flac"
        elif api_quality in ("HIGH", "LOW"):
            ext = ".m4a"
        else:
            ext = ".flac"

        filename = sanitize_filename(f"{m_artist} - {m_title}{ext}")
        file_path = os.path.join(dl_dir, filename)

        # Download
        try:
            download_file(stream_url, file_path, log=log)
        except Exception as e:
            log(f"[monochrome] Download failed for {query}: {e}")
            failed_tracks.append(query)
            sp_id = track.get("sp_id")
            if sp_id:
                failed_urls.append(f"https://open.spotify.com/track/{sp_id}")
            if i < total - 1:
                time.sleep(0.5)
            continue

        # Cover art and metadata
        cover_data = fetch_cover_art(info.get("album"), log=log)
        embed_metadata(file_path, info, cover_data, log=log)

        # Convert to MP3 if requested
        if want_mp3:
            mp3_path = os.path.join(dl_dir, sanitize_filename(f"{m_artist} - {m_title}.mp3"))
            if convert_to_mp3(file_path, mp3_path, log=log):
                embed_metadata(mp3_path, info, cover_data, log=log)
                file_path = mp3_path

        # Rename from embedded metadata for consistent naming
        final_path = rename_from_metadata(file_path)
        log(f"[monochrome] Saved: {final_path.name}")

        success += 1
        last_final_path = final_path

        # Rate limit between tracks
        if i < total - 1:
            time.sleep(0.5)

    # Wrap single tracks in a Title - Artist folder
    if total == 1 and success == 1 and last_final_path:
        folder_name = sanitize_filename(last_final_path.stem)
        wrapper_dir = os.path.join(output_dir, folder_name)
        os.makedirs(wrapper_dir, exist_ok=True)
        shutil.move(str(last_final_path), os.path.join(wrapper_dir, last_final_path.name))
        subfolder_name = folder_name
        fail_info["subfolder"] = subfolder_name
        log(f"[monochrome] Saved to folder: {folder_name}")

    # Summary
    if failed_tracks:
        log(f"[monochrome] Failed tracks ({len(failed_tracks)}):")
        for ft in failed_tracks:
            log(f"[monochrome]   - {ft}")

    log(f"[monochrome] Complete: {success}/{total} tracks downloaded")
    fail_info["failed_urls"] = failed_urls
    return success, total, fail_info