"""Identity parser for extracting movie and series information from filenames.

This module provides functionality to parse video filenames and extract
logical identities such as movie titles/years and series titles/seasons/episodes.
"""

import re
from typing import Optional

from vlm.config import DEFAULT_VIDEO_EXTENSIONS
from vlm.models import MovieIdentity, SeriesIdentity

# Quality tags to remove from titles
QUALITY_TAGS = [
    r'\b1080p\b', r'\b720p\b', r'\b480p\b', r'\b2160p\b',
    r'\b4K\b', r'\bUHD\b', r'\bHD\b',
    r'\bBluRay\b', r'\bBlu-Ray\b', r'\bBRRip\b', r'\bBDRip\b',
    r'\bWEB-DL\b', r'\bWEBRip\b', r'\bWEB\b',
    r'\bHDTV\b', r'\bHDRip\b',
    r'\bDVDRip\b', r'\bDVD\b',
    r'\bx264\b', r'\bx265\b', r'\bh264\b', r'\bh265\b', r'\bHEVC\b',
    r'\bAAC\b', r'\bAC3\b', r'\bDTS\b',
    r'\b10bit\b', r'\b8bit\b',
]

# Release group patterns (in brackets, but NOT years in parentheses)
RELEASE_GROUP_PATTERNS = [
    r'\[[\w\s\-\.]+\]',  # [RARBG], [YTS], etc.
]


def remove_quality_tags(text: str) -> str:
    """Remove quality indicators from text.
    
    Args:
        text: Input text containing potential quality tags
        
    Returns:
        Text with quality tags removed
    """
    result = text
    for pattern in QUALITY_TAGS:
        result = re.sub(pattern, '', result, flags=re.IGNORECASE)
    return result


def remove_release_groups(text: str) -> str:
    """Remove release group tags from text.
    
    Args:
        text: Input text containing potential release group tags
        
    Returns:
        Text with release group tags removed
    """
    result = text
    for pattern in RELEASE_GROUP_PATTERNS:
        result = re.sub(pattern, '', result)
    return result


def normalize_title(title: str) -> str:
    """Normalize a title by cleaning separators and whitespace.
    
    Args:
        title: Raw title string
        
    Returns:
        Normalized title with cleaned separators and spacing
    """
    # Replace dots and underscores with spaces
    title = title.replace('.', ' ').replace('_', ' ')
    
    # Remove extra whitespace
    title = ' '.join(title.split())
    
    return title.strip()


def parse_movie(
    filename: str,
    extensions: Optional[list[str]] = None,
) -> MovieIdentity:
    """Parse a movie filename to extract title and year.
    
    Supports patterns:
    - Title (Year)
    - Title.Year
    - Title - Year
    - Title Year
    
    Args:
        filename: Movie filename to parse
        extensions: Video extensions to strip (default: DEFAULT_VIDEO_EXTENSIONS)
        
    Returns:
        MovieIdentity with extracted information
    """
    if extensions is None:
        extensions = DEFAULT_VIDEO_EXTENSIONS
    # Remove file extension
    name_without_ext = filename
    for ext in extensions:
        if name_without_ext.lower().endswith(ext.lower()):
            name_without_ext = name_without_ext[:-len(ext)]
            break
    
    # Try different patterns in order of confidence BEFORE cleaning
    # This preserves the year in parentheses
    patterns = [
        # Pattern: Title (Year) - High confidence
        (r'^(.+?)\s*\((\d{4})\)', 0.9),
        # Pattern: Title.Year or Title-Year - High confidence
        (r'^(.+?)[\.\-](\d{4})', 0.9),
        # Pattern: Title - Year - Medium confidence
        (r'^(.+?)\s+-\s+(\d{4})', 0.7),
        # Pattern: Title Year (4 digits at end) - Medium confidence
        (r'^(.+?)\s+(\d{4})(?:\s|$)', 0.7),
    ]
    
    for pattern, confidence in patterns:
        match = re.search(pattern, name_without_ext)
        if match:
            title = match.group(1)
            year = int(match.group(2))
            
            # Now clean the title
            title = remove_quality_tags(title)
            title = remove_release_groups(title)
            title = normalize_title(title)
            
            return MovieIdentity(
                title=title,
                year=year,
                confidence=confidence,
                needs_review=False,
                original_filename=filename
            )
    
    # No year found - clean and extract title, flag for review
    cleaned = remove_quality_tags(name_without_ext)
    cleaned = remove_release_groups(cleaned)
    title = normalize_title(cleaned)
    
    return MovieIdentity(
        title=title,
        year=None,
        confidence=0.3,
        needs_review=True,
        original_filename=filename
    )


def parse_series(
    filename: str,
    extensions: Optional[list[str]] = None,
) -> SeriesIdentity:
    """Parse a series filename to extract title, season, and episode numbers.
    
    Supports patterns:
    - SXXEYY (e.g., S01E01)
    - SXXeYY (e.g., S01e01)
    - SeasonXEpisodeY (e.g., Season1Episode1)
    - XXxYY (e.g., 1x01)
    - Multi-episode: S01E01-E02, S01E01E02, etc.
    
    Args:
        filename: Series filename to parse
        extensions: Video extensions to strip (default: DEFAULT_VIDEO_EXTENSIONS)
        
    Returns:
        SeriesIdentity with extracted information
    """
    if extensions is None:
        extensions = DEFAULT_VIDEO_EXTENSIONS
    # Remove file extension
    name_without_ext = filename
    for ext in extensions:
        if name_without_ext.lower().endswith(ext.lower()):
            name_without_ext = name_without_ext[:-len(ext)]
            break
    
    # Try different patterns in order of confidence
    patterns = [
        # Pattern: SXXEYY or SXXeYY - High confidence
        # Also handles multi-episode: S01E01-E02, S01E01E02E03, etc.
        (r'[Ss](\d{1,2})[Ee](\d{1,2})', 0.9),
        # Pattern: XXxYY - High confidence (boundary-sensitive, avoid resolution substrings)
        (r'(?<!\d)(\d{1,2})x(\d{1,2})(?!\d)', 0.9),
        # Pattern: Season X Episode Y - Medium confidence
        (r'[Ss]eason\s*(\d{1,2})\s*[Ee]pisode\s*(\d{1,2})', 0.7),
    ]
    
    season = None
    episodes = []
    confidence = 0.0
    title_part = name_without_ext
    
    for pattern, conf in patterns:
        match = re.search(pattern, name_without_ext, re.IGNORECASE)
        if match:
            season = int(match.group(1))
            episodes = [int(match.group(2))]
            confidence = conf
            
            # Extract title (everything before the match)
            title_part = name_without_ext[:match.start()]
            
            # Handle multi-episode files for SXXEYY pattern
            if pattern.startswith(r'[Ss]'):
                # Find the full episode section (from S01E01 onwards)
                remaining = name_without_ext[match.start():]
                
                # Look for all episode numbers: E01, -E02, E03, etc.
                all_episode_matches = re.findall(r'[Ee](\d{1,2})', remaining)
                if all_episode_matches:
                    episodes = [int(ep) for ep in all_episode_matches]
            
            break
    
    # Clean the title
    if title_part:
        title_part = remove_quality_tags(title_part)
        title_part = remove_release_groups(title_part)
        title_part = normalize_title(title_part)
    else:
        # If no title part found, use the whole filename cleaned
        title_part = remove_quality_tags(name_without_ext)
        title_part = remove_release_groups(title_part)
        title_part = normalize_title(title_part)
    
    # Determine if review is needed
    needs_review = season is None or len(episodes) == 0
    
    # If no pattern matched, set low confidence
    if season is None:
        confidence = 0.3
    
    return SeriesIdentity(
        title=title_part,
        season=season,
        episodes=episodes,
        confidence=confidence,
        needs_review=needs_review,
        original_filename=filename
    )


def group_episodes(episodes: list[SeriesIdentity]) -> dict[tuple[str, int], list[SeriesIdentity]]:
    """Group parsed episodes by normalized series title and season number.
    
    Episodes are grouped by (normalized_title, season) tuple. Episodes with
    season=None are excluded from grouping as they need manual review.
    
    Args:
        episodes: List of parsed series identities
        
    Returns:
        Dictionary mapping (title, season) tuples to lists of SeriesIdentity objects
    """
    groups: dict[tuple[str, int], list[SeriesIdentity]] = {}
    
    for episode in episodes:
        # Skip episodes without season (they need manual review)
        if episode.season is None:
            continue
        
        # Create grouping key from normalized title and season
        key = (episode.title, episode.season)
        
        # Add episode to the appropriate group
        if key not in groups:
            groups[key] = []
        groups[key].append(episode)
    
    return groups