"""
Configuration management for Silver Table Assistant.
Centralized settings with environment variable support.
"""

import os
from datetime import datetime
from typing import List


class Settings:
    """Application settings with environment variable support."""
    
    def __init__(self):
        # Database Configuration
        self.supabase_url = os.getenv("SUPABASE_URL")
        self.supabase_service_role_key = os.getenv("SUPABASE_SERVICE_ROLE_KEY")
        
        # AI Service Configuration
        self.openai_api_key = os.getenv("OPENAI_API_KEY")
        self.openai_base_url = os.getenv("OPENAI_BASE_URL", "https://api.openai.com/v1")
        
        # LiteLLM Configuration (alternative to OpenAI)
        self.litellm_base_url = os.getenv("LITELLM_BASE_URL")
        self.litellm_api_key = os.getenv("LITELLM_API_KEY")
        self.litellm_model = os.getenv("LITELLM_MODEL", "azure-gpt-4.1")
        
        # Payment Service Configuration
        self.stripe_secret_key = os.getenv("STRIPE_SECRET_KEY")
        self.stripe_publishable_key = os.getenv("STRIPE_PUBLISHABLE_KEY")
        self.stripe_webhook_secret = os.getenv("STRIPE_WEBHOOK_SECRET")
        self.stripe_default_currency = "twd"  # Taiwan Dollar
        
        # Application Configuration
        self.frontend_url = os.getenv("FRONTEND_URL", "https://silver-esg.vercel.app")
        self.api_version = os.getenv("API_VERSION", "1.0.0")
        self.environment = os.getenv("ENVIRONMENT", "development")
        
        # Server Configuration
        self.host = os.getenv("HOST", "0.0.0.0")
        self.port = int(os.getenv("PORT", "8000"))
        
        # AI Model Configuration (for LiteLLM)
        self.ai_model_name = os.getenv("AI_MODEL_NAME", "azure-gpt-4.1")
        self.ai_max_tokens = 2000
        self.ai_temperature = 0.7
        
        # Currency Configuration
        self.default_currency = "twd"
        self.currency_symbol = "NT$"
        self.min_order_amount = 1000  # cents (NT$10)
        self.max_order_amount = 1000000  # cents (NT$10,000)
        self.min_donation_amount = 50  # NT$50 minimum for Stripe
        # Backwards-compatible uppercase constant
        self.MIN_DONATION_AMOUNT = self.min_donation_amount
        
        # Security Configuration
        self.jwt_secret_key = os.getenv("JWT_SECRET_KEY", "your-secret-key-here")
        self.access_token_expire_minutes = 30
        
        # CORS Configuration
        self.cors_origins = self._parse_cors_origins()
        
        # Validation
        self._validate_required_settings()
    
    def _parse_cors_origins(self) -> List[str]:
        """Parse CORS origins from environment variable."""
        origins_str = os.getenv("CORS_ORIGINS", "http://localhost:3000,http://localhost:5173")
        return [origin.strip() for origin in origins_str.split(",")]
    
    def _validate_required_settings(self):
        """Validate required environment variables."""
        required_vars = [
            "SUPABASE_URL",
            "SUPABASE_SERVICE_ROLE_KEY",
            "OPENAI_API_KEY",
            "STRIPE_SECRET_KEY",
            "STRIPE_WEBHOOK_SECRET"
        ]
        
        missing_vars = []
        for var in required_vars:
            if not os.getenv(var):
                missing_vars.append(var)
        
        if missing_vars:
            raise ValueError(f"Missing required environment variables: {', '.join(missing_vars)}")
    
    def get_current_timestamp(self) -> str:
        """Get current timestamp in ISO format."""
        return datetime.utcnow().isoformat() + "Z"
    
    def is_development(self) -> bool:
        """Check if running in development mode."""
        return self.environment.lower() == "development"
    
    def is_production(self) -> bool:
        """Check if running in production mode."""
        return self.environment.lower() == "production"
    
    def format_currency(self, amount_cents: int) -> str:
        """Format amount in cents to currency string."""
        return f"{self.currency_symbol}{amount_cents / 100:.2f}"


# Global settings instance
settings = Settings()