"""
Channel Processor - Handles channel processing, country detection, and M3U parsing
"""

import re
import os
import logging
import shutil
from datetime import datetime
from typing import Dict, List, Optional, Set

class ChannelProcessor:
    """High-performance channel processing with optimizations."""
    
    def __init__(self, config):
        self.config = config
        self.logger = logging.getLogger(__name__)
        
        # Pre-compile regex patterns for performance
        self._compile_patterns()
        
        # Caches for performance
        self._country_cache: Dict[str, str] = {}
        self._signature_cache: Dict[str, str] = {}
    
    def _compile_patterns(self):
        """Pre-compile regex patterns for better performance."""
        self.url_fix_patterns = [
            (re.compile(r'(https?://[^\s#]+)(#EXTINF)'), r'\1\n\2'),
            (re.compile(r'(\.m3u8?)(#EXTINF)'), r'\1\n\2'),
            (re.compile(r'([^#\n])#EXTINF'), r'\1\n#EXTINF')
        ]
        
        self.extinf_patterns = {
            'tvg_id': re.compile(r'tvg-id="([^"]*)"'),
            'tvg_logo': re.compile(r'tvg-logo="([^"]*)"'),
            'group_title': re.compile(r'group-title="([^"]*)"'),
            'stream_name': re.compile(r',\s*(.+)$')
        }
    
    def detect_country_from_channel(self, channel_name: str, epg_id: str = "", logo_url: str = "") -> str:
        """Optimized country detection with caching."""
        # Create cache key
        cache_key = f"{channel_name}|{epg_id}|{logo_url}"
        if cache_key in self._country_cache:
            return self._country_cache[cache_key]
        
        all_text = f"{channel_name.lower().strip()} {epg_id.lower().strip()} {logo_url.lower().strip()}"
        
        # Check prefixes first (more specific)
        for country, prefixes in self.config.patterns["country_prefixes"].items():
            for prefix in prefixes:
                if prefix in all_text:
                    self._country_cache[cache_key] = country
                    self.logger.debug(f"Detected {country} for: {channel_name} (prefix: '{prefix}')")
                    return country
        
        # Check general patterns
        for country, keywords in self.config.patterns["country_patterns"].items():
            for keyword in keywords:
                if keyword in all_text:
                    self._country_cache[cache_key] = country
                    self.logger.debug(f"Detected {country} for: {channel_name} (keyword: '{keyword}')")
                    return country
        
        # Cache negative result too
        self._country_cache[cache_key] = "Uncategorized"
        return "Uncategorized"
    
    def detect_quality(self, channel_name: str) -> str:
        """Detect quality with configurable patterns."""
        name_lower = channel_name.lower()
        
        for quality, patterns in self.config.patterns["quality_patterns"].items():
            if any(pattern in name_lower for pattern in patterns):
                return quality
        
        return ""
    
    def is_adult_content(self, channel_name: str) -> bool:
        """Check for adult content with configurable keywords."""
        name_lower = channel_name.lower()
        return any(keyword in name_lower for keyword in self.config.patterns["adult_keywords"])
    
    def validate_channel(self, channel: Dict) -> tuple:
        """Enhanced channel validation."""
        name = channel.get('Stream name', '').strip()
        url = channel.get('Stream URL', '').strip()
        
        if not name or not url:
            return False, "Missing name or URL"
        if len(name) < self.config.settings.get('min_channel_name_length', 2):
            return False, "Name too short"
        if self.config.settings.get('skip_adult_content', True) and self.is_adult_content(name):
            return False, "Adult content filtered"
        if not (url.startswith('http') or url.startswith('rtmp')):
            return False, "Invalid URL"
        
        return True, "Valid"
    
    def apply_auto_detection(self, channel: Dict) -> Dict:
        """Apply country detection and quality tags."""
        stream_name = channel.get('Stream name', '')
        epg_id = channel.get('EPG id', '')
        logo_url = channel.get('Logo', '')
        
        # Manual overrides first
        for key, new_group in self.config.group_overrides.items():
            if key.lower() in stream_name.lower():
                channel['Group'] = new_group
                return channel
        
        # Add quality tag
        if self.config.settings.get('detect_quality', True):
            quality = self.detect_quality(stream_name)
            if quality and quality not in stream_name:
                channel['Stream name'] = f"{stream_name} [{quality}]"
        
        # Auto-detect country
        if self.config.settings.get('auto_detect_country', True):
            detected_country = self.detect_country_from_channel(stream_name, epg_id, logo_url)
            channel['Group'] = detected_country
            self.logger.debug(f"Auto-detected: '{stream_name}' → {detected_country}")
        
        return channel
    
    def get_channel_signature(self, channel: Dict) -> str:
        """Optimized signature generation with caching."""
        name = channel.get('Stream name', '').strip().lower()
        url = channel.get('Stream URL', '').strip().lower()
        
        cache_key = f"{name}|{url}"
        if cache_key in self._signature_cache:
            return self._signature_cache[cache_key]
        
        # Clean name
        name_clean = re.sub(r'\s+', ' ', name)
        name_clean = re.sub(r'[^\w\s]', '', name_clean)
        name_clean = re.sub(r'\b(hd|fhd|4k|uhd|sd)\b', '', name_clean).strip()
        
        # Clean URL
        url_clean = url.split('?')[0] if '?' in url else url
        
        signature = f"{name_clean}|{url_clean}"
        self._signature_cache[cache_key] = signature
        return signature
    
    def remove_duplicates_optimized(self, channels: List[Dict]) -> List[Dict]:
        """High-performance duplicate removal using sets."""
        if not self.config.settings.get('remove_duplicates', True):
            return channels
        
        seen_signatures: Set[str] = set()
        unique_channels: List[Dict] = []
        duplicates = 0
        
        for channel in channels:
            signature = self.get_channel_signature(channel)
            if signature not in seen_signatures:
                seen_signatures.add(signature)
                unique_channels.append(channel)
            else:
                duplicates += 1
        
        if duplicates > 0:
            self.logger.info(f"Removed {duplicates} duplicate channels")
        
        return unique_channels
    
    def parse_channel_block(self, block: str) -> Optional[Dict]:
        """Parse channel block from channels.txt."""
        channel_data = {}
        lines = block.strip().split('\n')
        
        for line in lines:
            if '=' in line:
                key, value = line.split('=', 1)
                channel_data[key.strip()] = value.strip()
        
        return channel_data if channel_data else None
    
    def parse_m3u_entry(self, extinf_line: str, url_line: str) -> Dict:
        """Enhanced M3U entry parsing using pre-compiled patterns."""
        channel = {}
        
        try:
            for field, pattern in self.extinf_patterns.items():
                match = pattern.search(extinf_line)
                if field == 'tvg_id':
                    channel['EPG id'] = match.group(1) if match else ''
                elif field == 'tvg_logo':
                    channel['Logo'] = match.group(1) if match else ''
                elif field == 'group_title':
                    channel['Group'] = match.group(1) if match else 'Uncategorized'
                elif field == 'stream_name':
                    if match:
                        stream_name = match.group(1).strip()
                        channel['Stream name'] = re.sub(r'\s+', ' ', stream_name)
                    else:
                        channel['Stream name'] = 'Unknown Channel'
            
            channel['Stream URL'] = url_line.strip()
            
        except Exception as e:
            self.logger.warning(f"Error parsing M3U entry: {e}")
            channel = {
                'EPG id': '', 'Logo': '', 'Group': 'Uncategorized',
                'Stream name': 'Parse Error', 'Stream URL': url_line.strip()
            }
        
        return channel
    
    def convert_to_channels_txt_block(self, channel_data: Dict) -> str:
        """Convert to channels.txt format."""
        block = []
        block.append(f"Group = {channel_data.get('Group', 'Uncategorized')}")
        block.append(f"Stream name = {channel_data.get('Stream name', 'Unknown Channel')}")
        block.append(f"Logo = {channel_data.get('Logo', '')}")
        block.append(f"EPG id = {channel_data.get('EPG id', '')}")
        block.append(f"Stream URL = {channel_data.get('Stream URL', '')}")
        return "\n".join(block)
    
    def clean_corrupted_channels(self):
        """Clean up any corrupted entries in existing channels.txt"""
        if not os.path.exists(self.config.channels_file):
            return
        
        self.logger.info("Cleaning up any corrupted entries in channels.txt...")
        
        with open(self.config.channels_file, 'r', encoding='utf-8') as f:
            content = f.read()
        
        channel_blocks = re.split(r'\n\s*\n+', content.strip())
        cleaned_channels = []
        fixed_count = 0
        
        for block in channel_blocks:
            if block.strip():
                channel = self.parse_channel_block(block)
                if channel:
                    # Clean corrupted Stream URL
                    stream_url = channel.get('Stream URL', '')
                    if '#EXTINF' in stream_url or 'group-title=' in stream_url:
                        if '#EXTINF' in stream_url:
                            stream_url = stream_url.split('#EXTINF')[0].strip()
                        if 'group-title=' in stream_url:
                            stream_url = stream_url.split('group-title=')[0].strip()
                        channel['Stream URL'] = stream_url
                        fixed_count += 1
                        self.logger.info(f"Fixed corrupted URL for: {channel.get('Stream name')}")
                    
                    # Clean corrupted Logo URL
                    logo_url = channel.get('Logo', '')
                    if logo_url and ('group-title=' in logo_url or '#EXTINF' in logo_url):
                        if 'group-title=' in logo_url:
                            logo_url = logo_url.split('group-title=')[0].strip()
                        if '#EXTINF' in logo_url:
                            logo_url = logo_url.split('#EXTINF')[0].strip()
                        channel['Logo'] = logo_url
                        fixed_count += 1
                        self.logger.info(f"Fixed corrupted logo for: {channel.get('Stream name')}")
                    
                    cleaned_channels.append(channel)
        
        if fixed_count > 0:
            self.logger.info(f"Fixed {fixed_count} corrupted entries, rewriting file...")
            
            # Create backup
            self._create_backup(self.config.channels_file)
            
            with open(self.config.channels_file, 'w', encoding='utf-8') as f:
                for i, channel in enumerate(cleaned_channels):
                    if i > 0:
                        f.write("\n\n")
                    f.write(self.convert_to_channels_txt_block(channel))
            
            self.logger.info(f"Successfully cleaned and rewrote channels.txt")
        else:
            self.logger.info("No corrupted entries found to fix")
    
    def update_existing_channels_with_country_detection(self):
        """FIXED: Re-detect countries for existing channels - FORCE UPDATE ALL."""
        if not os.path.exists(self.config.channels_file):
            return
        
        self.logger.info("FORCE re-detecting countries for ALL existing channels...")
        
        with open(self.config.channels_file, 'r', encoding='utf-8') as f:
            content = f.read()
        
        channel_blocks = re.split(r'\n\s*\n+', content.strip())
        updated_channels = []
        changes = 0
        
        for block in channel_blocks:
            if block.strip():
                channel = self.parse_channel_block(block)
                if channel:
                    old_group = channel.get('Group', 'Uncategorized')
                    stream_name = channel.get('Stream name', '')
                    epg_id = channel.get('EPG id', '')
                    logo_url = channel.get('Logo', '')
                    
                    # FORCE detection for ALL channels
                    detected = self.detect_country_from_channel(stream_name, epg_id, logo_url)
                    
                    # Always update the group
                    channel['Group'] = detected
                    if old_group != detected:
                        changes += 1
                        self.logger.info(f"FORCED UPDATE: '{stream_name}' from '{old_group}' to '{detected}'")
                    
                    updated_channels.append(channel)
        
        if updated_channels:
            # Create backup and rewrite
            self._create_backup(self.config.channels_file)
            
            with open(self.config.channels_file, 'w', encoding='utf-8') as f:
                for i, channel in enumerate(updated_channels):
                    if i > 0:
                        f.write("\n\n")
                    f.write(self.convert_to_channels_txt_block(channel))
            
            self.logger.info(f"FORCE updated ALL {len(updated_channels)} channels ({changes} changes made)")
    
    def process_import(self) -> List[Dict]:
        """Enhanced M3U import with robust error handling."""
        if not os.path.exists(self.config.import_file):
            self.logger.info("No import file found, skipping import")
            return []

        self.logger.info(f"Processing {self.config.import_file}...")
        
        imported_channels = []
        
        try:
            with open(self.config.import_file, 'r', encoding='utf-8') as f:
                content = f.read()
            
            # Pre-process content with optimized regex
            for pattern, replacement in self.url_fix_patterns:
                content = pattern.sub(replacement, content)
            
            lines = content.split('\n')
            self.logger.info(f"Processing {len(lines)} lines after pre-processing...")

            i = 0
            while i < len(lines):
                line = lines[i].strip()
                
                if line.startswith('#EXTINF:'):
                    url_line = self._find_url_line(lines, i + 1)
                    if url_line:
                        channel = self.parse_m3u_entry(line, url_line)
                        is_valid, reason = self.validate_channel(channel)
                        
                        if is_valid:
                            channel = self.apply_auto_detection(channel)
                            imported_channels.append(channel)
                        else:
                            self.logger.debug(f"Filtered channel: {channel.get('Stream name')} - {reason}")
                
                i += 1
            
            # Cleanup import file
            if self.config.settings.get('auto_cleanup_import', True):
                os.remove(self.config.import_file)
                self.logger.info("Cleaned up import file")
            
            self.logger.info(f"Successfully imported {len(imported_channels)} channels")
            return imported_channels
            
        except Exception as e:
            self.logger.error(f"Error processing import: {e}")
            return []
    
    def _find_url_line(self, lines: List[str], start_idx: int) -> Optional[str]:
        """Find the URL line following an EXTINF line."""
        for j in range(start_idx, min(len(lines), start_idx + 5)):
            potential_url = lines[j].strip()
            
            if not potential_url or potential_url.startswith('#'):
                continue
            
            # Clean and validate URL
            if '#EXTINF' in potential_url:
                potential_url = potential_url.split('#EXTINF')[0].strip()
            
            if (potential_url.startswith(('http://', 'https://', 'rtmp://')) or
                potential_url.endswith(('.m3u8', '.ts', '.mp4')) or
                '/' in potential_url):
                return potential_url
        
        return None
    
    def _create_backup(self, file_path: str):
        """Create a simple backup."""
        if os.path.exists(file_path):
            timestamp = datetime.now().strftime('%Y%m%d_%H%M%S')
            backup_name = f"{file_path}.backup.{timestamp}"
            try:
                shutil.copy2(file_path, backup_name)
                self.logger.info(f"Created backup: {backup_name}")
            except Exception as e:
                self.logger.warning(f"Could not create backup: {e}")