"""
Configuration management for ARF Demo
Updated for Pydantic v2 with pydantic-settings
"""
from typing import Optional, Dict, Any, List
from enum import Enum
import os
import logging

logger = logging.getLogger(__name__)

# Try to import from pydantic-settings, fallback to pydantic
try:
    from pydantic_settings import BaseSettings
    from pydantic import Field, validator
    PYDANTIC_V2 = True
    logger.info("Using pydantic-settings for BaseSettings")
except ImportError:
    try:
        from pydantic import BaseSettings, Field, validator
        PYDANTIC_V2 = False
        logger.info("Using pydantic.BaseSettings (older version)")
    except ImportError as e:
        logger.error(f"Failed to import pydantic: {e}")
        # Create minimal fallback
        class BaseSettings:
            def __init__(self, **kwargs):
                for k, v in kwargs.items():
                    setattr(self, k, v)
        
        class Field:
            @staticmethod
            def default(value):
                return value
        
        def validator(*args, **kwargs):
            def decorator(func):
                return func
            return decorator
        
        PYDANTIC_V2 = False


class ARFMode(str, Enum):
    """ARF operation modes"""
    DEMO = "demo"
    OSS = "oss"
    ENTERPRISE = "enterprise"


class SafetyMode(str, Enum):
    """Safety modes for execution"""
    ADVISORY = "advisory"
    APPROVAL = "approval"
    AUTONOMOUS = "autonomous"


class Settings(BaseSettings):
    """
    Application settings with environment variable support
    """
    
    # ===== System Mode =====
    arf_mode: ARFMode = Field(
        default=ARFMode.DEMO,
        description="ARF operation mode"
    )
    
    use_mock_arf: bool = Field(
        default=True,
        description="Use mock ARF implementation (for demo mode)"
    )
    
    # ===== ARF Configuration =====
    arf_api_key: Optional[str] = Field(
        default=None,
        description="ARF API key for real integration"
    )
    
    arf_base_url: str = Field(
        default="https://api.arf.dev",
        description="ARF API base URL"
    )
    
    # ===== Business Configuration =====
    engineer_hourly_rate: float = Field(
        default=150.0,
        description="Engineer hourly rate in USD"
    )
    
    engineer_annual_cost: float = Field(
        default=125000.0,
        description="Engineer annual cost in USD"
    )
    
    default_savings_rate: float = Field(
        default=0.82,
        description="Default savings rate with ARF"
    )
    
    # ===== UI Configuration =====
    auto_refresh_seconds: int = Field(
        default=30,
        description="Auto-refresh interval in seconds"
    )
    
    max_history_items: int = Field(
        default=100,
        description="Maximum history items to display"
    )
    
    # ===== Demo Configuration =====
    default_scenario: str = Field(
        default="Cache Miss Storm",
        description="Default incident scenario"
    )
    
    scenario_config_path: str = Field(
        default="config/scenarios",
        description="Path to scenario configuration files"
    )
    
    # ===== Safety Configuration =====
    default_safety_mode: SafetyMode = Field(
        default=SafetyMode.ADVISORY,
        description="Default safety mode"
    )
    
    require_approval: bool = Field(
        default=True,
        description="Require human approval for execution"
    )
    
    # ===== Validation =====
    @validator("arf_api_key")
    def validate_api_key(cls, v: Optional[str], values: Dict[str, Any]) -> Optional[str]:
        if values.get("arf_mode") == ARFMode.ENTERPRISE and not v:
            raise ValueError("ARF API key required for Enterprise mode")
        return v
    
    @validator("use_mock_arf")
    def validate_mock_mode(cls, v: bool, values: Dict[str, Any]) -> bool:
        if values.get("arf_mode") == ARFMode.DEMO:
            return True
        return v
    
    class Config:
        env_file = ".env"
        env_file_encoding = "utf-8"
        case_sensitive = False
        use_enum_values = True


# Global settings instance with fallback
try:
    settings = Settings()
except Exception as e:
    logger.warning(f"Failed to load settings from .env: {e}, using defaults")
    settings = Settings(
        arf_mode=ARFMode.DEMO,
        use_mock_arf=True,
        engineer_hourly_rate=150.0,
        engineer_annual_cost=125000.0,
        default_savings_rate=0.82,
        auto_refresh_seconds=30,
        max_history_items=100,
        default_scenario="Cache Miss Storm",
        scenario_config_path="config/scenarios",
        default_safety_mode=SafetyMode.ADVISORY,
        require_approval=True
    )


def get_settings() -> Settings:
    """Get settings instance (singleton pattern)"""
    return settings