"""
Application Configuration Module
Centralizes all application configuration and environment variable handling

Note: Named 'app_config.py' to avoid conflicts with existing 'Configs/' folder
"""

import os
from dataclasses import dataclass, asdict
from typing import Dict, Any, Optional
import logging

logger = logging.getLogger(__name__)

@dataclass
class ProcessingConfig:
    """
    Main processing configuration with environment variable defaults
    """
    # Frame processing settings
    keyframe_interval: int = int(os.getenv('KEYFRAME_INTERVAL', '5'))
    frame_skip: int = int(os.getenv('FRAME_SKIP', '1'))
    
    # Memory management
    memory_cleanup_interval: int = int(os.getenv('MEMORY_CLEANUP_INTERVAL', '30'))
    
    # Video constraints
    max_video_length: int = int(os.getenv('MAX_VIDEO_LENGTH', '300'))  # seconds
    max_video_resolution: str = os.getenv('MAX_VIDEO_RESOLUTION', '1920x1080')
    
    # Quality settings
    quality_preset: str = os.getenv('QUALITY_PRESET', 'balanced')
    
    # Model settings
    sam2_model_size: str = os.getenv('SAM2_MODEL_SIZE', 'large')  # tiny, small, base, large
    matanyone_precision: str = os.getenv('MATANYONE_PRECISION', 'fp32')  # fp16, fp32
    
    # Processing settings
    temporal_consistency: bool = os.getenv('TEMPORAL_CONSISTENCY', 'true').lower() == 'true'
    edge_refinement: bool = os.getenv('EDGE_REFINEMENT', 'true').lower() == 'true'
    
    # Output settings
    output_format: str = os.getenv('OUTPUT_FORMAT', 'mp4')
    output_quality: str = os.getenv('OUTPUT_QUALITY', 'high')  # low, medium, high
    preserve_audio: bool = os.getenv('PRESERVE_AUDIO', 'true').lower() == 'true'
    
    # Cache settings
    model_cache_dir: str = os.getenv('MODEL_CACHE_DIR', '/tmp/model_cache')
    temp_dir: str = os.getenv('TEMP_DIR', '/tmp')
    cleanup_temp_files: bool = os.getenv('CLEANUP_TEMP_FILES', 'true').lower() == 'true'
    
    # Performance settings
    max_concurrent_processes: int = int(os.getenv('MAX_CONCURRENT_PROCESSES', '1'))
    gpu_memory_fraction: float = float(os.getenv('GPU_MEMORY_FRACTION', '0.8'))
    
    # Debug settings
    debug_mode: bool = os.getenv('DEBUG_MODE', 'false').lower() == 'true'
    save_intermediate_results: bool = os.getenv('SAVE_INTERMEDIATE_RESULTS', 'false').lower() == 'true'
    
    def __post_init__(self):
        """Validate configuration after initialization"""
        self._validate_config()
        self._create_directories()
        if self.debug_mode:
            self._log_config()
    
    def _validate_config(self):
        """Validate configuration values"""
        # Validate frame settings
        if self.keyframe_interval < 1:
            logger.warning(f"keyframe_interval must be >= 1, got {self.keyframe_interval}. Setting to 1.")
            self.keyframe_interval = 1
        
        if self.frame_skip < 1:
            logger.warning(f"frame_skip must be >= 1, got {self.frame_skip}. Setting to 1.")
            self.frame_skip = 1
        
        # Validate memory settings
        if self.memory_cleanup_interval < 1:
            logger.warning(f"memory_cleanup_interval must be >= 1, got {self.memory_cleanup_interval}. Setting to 10.")
            self.memory_cleanup_interval = 10
        
        # Validate video constraints
        if self.max_video_length < 1:
            logger.warning(f"max_video_length must be >= 1, got {self.max_video_length}. Setting to 60.")
            self.max_video_length = 60
        
        # Validate resolution format
        if 'x' not in self.max_video_resolution:
            logger.warning(f"Invalid resolution format: {self.max_video_resolution}. Setting to 1920x1080.")
            self.max_video_resolution = '1920x1080'
        
        # Validate quality preset
        valid_presets = ['fast', 'balanced', 'high', 'ultra']
        if self.quality_preset not in valid_presets:
            logger.warning(f"Invalid quality preset: {self.quality_preset}. Setting to 'balanced'.")
            self.quality_preset = 'balanced'
        
        # Validate model settings
        valid_sam2_sizes = ['tiny', 'small', 'base', 'large']
        if self.sam2_model_size not in valid_sam2_sizes:
            logger.warning(f"Invalid SAM2 model size: {self.sam2_model_size}. Setting to 'large'.")
            self.sam2_model_size = 'large'
        
        valid_precisions = ['fp16', 'fp32']
        if self.matanyone_precision not in valid_precisions:
            logger.warning(f"Invalid precision: {self.matanyone_precision}. Setting to 'fp32'.")
            self.matanyone_precision = 'fp32'
        
        # Validate output settings
        valid_formats = ['mp4', 'avi', 'mov', 'webm']
        if self.output_format not in valid_formats:
            logger.warning(f"Invalid output format: {self.output_format}. Setting to 'mp4'.")
            self.output_format = 'mp4'
        
        valid_qualities = ['low', 'medium', 'high']
        if self.output_quality not in valid_qualities:
            logger.warning(f"Invalid output quality: {self.output_quality}. Setting to 'high'.")
            self.output_quality = 'high'
        
        # Validate performance settings
        if self.max_concurrent_processes < 1:
            logger.warning(f"max_concurrent_processes must be >= 1, got {self.max_concurrent_processes}. Setting to 1.")
            self.max_concurrent_processes = 1
        
        if not (0.1 <= self.gpu_memory_fraction <= 1.0):
            logger.warning(f"gpu_memory_fraction must be between 0.1 and 1.0, got {self.gpu_memory_fraction}. Setting to 0.8.")
            self.gpu_memory_fraction = 0.8
    
    def _create_directories(self):
        """Create necessary directories if they don't exist"""
        import os
        directories = [self.model_cache_dir, self.temp_dir]
        
        for directory in directories:
            try:
                os.makedirs(directory, exist_ok=True)
                logger.debug(f"Ensured directory exists: {directory}")
            except Exception as e:
                logger.error(f"Failed to create directory {directory}: {e}")
    
    def _log_config(self):
        """Log current configuration in debug mode"""
        logger.info("=== Processing Configuration ===")
        for key, value in asdict(self).items():
            logger.info(f"{key}: {value}")
        logger.info("===============================")
    
    def to_dict(self) -> Dict[str, Any]:
        """Convert configuration to dictionary"""
        return asdict(self)
    
    def get_quality_settings(self) -> Dict[str, Any]:
        """Get quality-specific settings based on preset"""
        quality_maps = {
            'fast': {
                'keyframe_interval': max(self.keyframe_interval, 10),
                'frame_skip': max(self.frame_skip, 2),
                'edge_refinement': False,
                'temporal_consistency': False,
                'model_precision': 'fp16'
            },
            'balanced': {
                'keyframe_interval': self.keyframe_interval,
                'frame_skip': self.frame_skip,
                'edge_refinement': True,
                'temporal_consistency': True,
                'model_precision': 'fp32'
            },
            'high': {
                'keyframe_interval': max(self.keyframe_interval // 2, 1),
                'frame_skip': 1,
                'edge_refinement': True,
                'temporal_consistency': True,
                'model_precision': 'fp32'
            },
            'ultra': {
                'keyframe_interval': 1,
                'frame_skip': 1,
                'edge_refinement': True,
                'temporal_consistency': True,
                'model_precision': 'fp32'
            }
        }
        
        return quality_maps.get(self.quality_preset, quality_maps['balanced'])
    
    def get_resolution_limits(self) -> tuple[int, int]:
        """Get max width and height from resolution setting"""
        try:
            width, height = map(int, self.max_video_resolution.split('x'))
            return width, height
        except ValueError:
            logger.error(f"Invalid resolution format: {self.max_video_resolution}")
            return 1920, 1080
    
    def is_high_performance_mode(self) -> bool:
        """Check if configuration is set for high performance"""
        return (
            self.quality_preset in ['high', 'ultra'] and
            self.edge_refinement and
            self.temporal_consistency and
            self.keyframe_interval <= 3
        )
    
    def get_memory_limits(self) -> Dict[str, float]:
        """Get memory-related limits"""
        return {
            'gpu_memory_fraction': self.gpu_memory_fraction,
            'cleanup_interval': self.memory_cleanup_interval,
            'max_concurrent': self.max_concurrent_processes
        }

# Singleton instance for application-wide use
_config_instance: Optional[ProcessingConfig] = None

def get_config() -> ProcessingConfig:
    """Get global configuration instance"""
    global _config_instance
    if _config_instance is None:
        _config_instance = ProcessingConfig()
    return _config_instance

def reload_config() -> ProcessingConfig:
    """Reload configuration from environment variables"""
    global _config_instance
    _config_instance = ProcessingConfig()
    logger.info("Configuration reloaded from environment variables")
    return _config_instance

def update_config(**kwargs) -> ProcessingConfig:
    """Update configuration with new values"""
    global _config_instance
    if _config_instance is None:
        _config_instance = ProcessingConfig()
    
    for key, value in kwargs.items():
        if hasattr(_config_instance, key):
            setattr(_config_instance, key, value)
            logger.debug(f"Updated config: {key} = {value}")
        else:
            logger.warning(f"Unknown configuration key: {key}")
    
    # Re-validate after updates
    _config_instance._validate_config()
    return _config_instance