"""
Shared Configuration Module for Medium Agent Ecosystem

This module provides a centralized configuration system that both
Medium-Scraper and medium-mcp-server can import and extend.

Maintains backward compatibility while providing a single source of truth.
"""

import os
from dataclasses import dataclass, field
from typing import Optional, Dict, Any
from pathlib import Path


@dataclass
class SharedConfig:
    """
    Shared configuration for the Medium Agent ecosystem.
    
    Both Medium-Scraper and medium-mcp-server extend this base config.
    All settings can be overridden via environment variables.
    """
    
    # ========================================================================
    # Scraper Settings
    # ========================================================================
    max_workers: int = 5
    max_batch_size: int = 20
    default_timeout: int = 30
    max_concurrency: int = 5
    
    # ========================================================================
    # API Keys
    # ========================================================================
    groq_api_key: Optional[str] = None
    gemini_api_key: Optional[str] = None
    openai_api_key: Optional[str] = None
    elevenlabs_api_key: Optional[str] = None
    
    # ========================================================================
    # HTTP Settings (Connection Pooling)
    # ========================================================================
    max_connections: int = 100
    max_keepalive_connections: int = 20
    keepalive_expiry: float = 5.0
    http_timeout: int = 30
    enable_http2: bool = True
    
    # ========================================================================
    # Rate Limiting
    # ========================================================================
    requests_per_minute: int = 60
    enable_rate_limiting: bool = True
    
    # ========================================================================
    # Database Settings
    # ========================================================================
    db_pool_size: int = 5
    db_timeout: int = 30
    enable_async_db: bool = True
    db_wal_mode: bool = True  # Write-Ahead Logging for better concurrency
    
    # ========================================================================
    # Resilience Settings
    # ========================================================================
    circuit_breaker_threshold: int = 5
    circuit_breaker_timeout: int = 300
    max_retries: int = 3
    retry_backoff_base: float = 1.0  # Initial delay in seconds
    retry_backoff_multiplier: float = 2.0  # Exponential multiplier
    
    # ========================================================================
    # Logging Settings
    # ========================================================================
    log_level: str = "INFO"
    enable_structured_logging: bool = True
    log_format: str = "json"  # "json" or "console"
    
    # ========================================================================
    # Cache Settings
    # ========================================================================
    enable_caching: bool = True
    cache_ttl: int = 3600  # 1 hour default
    cache_max_size: int = 1000  # Max items in memory cache
    
    # ========================================================================
    # Paths
    # ========================================================================
    base_dir: Path = field(default_factory=lambda: Path(__file__).parent)
    db_path: Optional[Path] = None
    output_dir: Optional[Path] = None
    
    @classmethod
    def from_env(cls, env_prefix: str = "") -> "SharedConfig":
        """
        Load configuration from environment variables.
        
        Args:
            env_prefix: Optional prefix for environment variables
                       (e.g., "MCP_" or "SCRAPER_")
        
        Returns:
            SharedConfig instance with values from environment
        """
        def get_env(key: str, default: Any = None, cast_type=str) -> Any:
            """Get environment variable with optional prefix and type casting."""
            env_key = f"{env_prefix}{key}" if env_prefix else key
            value = os.getenv(env_key, os.getenv(key, default))
            
            if value is None:
                return default
            
            # Type casting
            if cast_type == bool:
                return str(value).lower() in ('true', '1', 'yes', 'on')
            elif cast_type == int:
                return int(value)
            elif cast_type == float:
                return float(value)
            else:
                return value
        
        return cls(
            # Scraper settings
            max_workers=get_env("MAX_WORKERS", 5, int),
            max_batch_size=get_env("MAX_BATCH_SIZE", 20, int),
            default_timeout=get_env("DEFAULT_TIMEOUT", 30, int),
            max_concurrency=get_env("MAX_CONCURRENCY", 5, int),
            
            # API Keys
            groq_api_key=get_env("GROQ_API_KEY"),
            gemini_api_key=get_env("GEMINI_API_KEY"),
            openai_api_key=get_env("OPENAI_API_KEY"),
            elevenlabs_api_key=get_env("ELEVENLABS_API_KEY"),
            
            # HTTP Settings
            max_connections=get_env("HTTP_MAX_CONNECTIONS", 100, int),
            max_keepalive_connections=get_env("HTTP_MAX_KEEPALIVE", 20, int),
            keepalive_expiry=get_env("HTTP_KEEPALIVE_EXPIRY", 5.0, float),
            http_timeout=get_env("HTTP_TIMEOUT", 30, int),
            enable_http2=get_env("ENABLE_HTTP2", True, bool),
            
            # Rate Limiting
            requests_per_minute=get_env("RATE_LIMIT_RPM", 60, int),
            enable_rate_limiting=get_env("ENABLE_RATE_LIMITING", True, bool),
            
            # Database
            db_pool_size=get_env("DB_POOL_SIZE", 5, int),
            db_timeout=get_env("DB_TIMEOUT", 30, int),
            enable_async_db=get_env("ENABLE_ASYNC_DB", True, bool),
            db_wal_mode=get_env("DB_WAL_MODE", True, bool),
            
            # Resilience
            circuit_breaker_threshold=get_env("CIRCUIT_BREAKER_THRESHOLD", 5, int),
            circuit_breaker_timeout=get_env("CIRCUIT_BREAKER_TIMEOUT", 300, int),
            max_retries=get_env("MAX_RETRIES", 3, int),
            retry_backoff_base=get_env("RETRY_BACKOFF_BASE", 1.0, float),
            retry_backoff_multiplier=get_env("RETRY_BACKOFF_MULTIPLIER", 2.0, float),
            
            # Logging
            log_level=get_env("LOG_LEVEL", "INFO"),
            enable_structured_logging=get_env("ENABLE_STRUCTURED_LOGGING", True, bool),
            log_format=get_env("LOG_FORMAT", "json"),
            
            # Cache
            enable_caching=get_env("ENABLE_CACHING", True, bool),
            cache_ttl=get_env("CACHE_TTL", 3600, int),
            cache_max_size=get_env("CACHE_MAX_SIZE", 1000, int),
        )
    
    def to_dict(self) -> Dict[str, Any]:
        """Convert configuration to dictionary."""
        return {
            k: str(v) if isinstance(v, Path) else v
            for k, v in self.__dict__.items()
        }
    
    def __repr__(self) -> str:
        """String representation with sensitive data masked."""
        safe_dict = self.to_dict()
        
        # Mask sensitive keys
        sensitive_keys = ['groq_api_key', 'gemini_api_key', 'openai_api_key', 'elevenlabs_api_key']
        for key in sensitive_keys:
            if safe_dict.get(key):
                safe_dict[key] = safe_dict[key][:8] + "..." if safe_dict[key] else None
        
        return f"SharedConfig({safe_dict})"


# Singleton instance for global access (optional)
_global_config: Optional[SharedConfig] = None


def get_config(reload: bool = False) -> SharedConfig:
    """
    Get global configuration instance.
    
    Args:
        reload: If True, reload config from environment
    
    Returns:
        SharedConfig instance
    """
    global _global_config
    
    if _global_config is None or reload:
        _global_config = SharedConfig.from_env()
    
    return _global_config


def set_config(config: SharedConfig) -> None:
    """
    Set global configuration instance.
    
    Args:
        config: SharedConfig instance to use globally
    """
    global _global_config
    _global_config = config