"""
Centralized configuration for API keys, models, and application settings
"""

import os
import logging
from typing import Optional
from pathlib import Path

from pydantic_settings import BaseSettings
from pydantic import Field


# ============================================================================
# Settings Class
# ============================================================================

class Settings(BaseSettings):
    """
    Application settings loaded from environment variables

    Environment variables can be set in:
    1. System environment
    2. .env file in project root
    3. Passed explicitly when creating Settings instance
    """

    # ========================================================================
    # API Keys
    # ========================================================================

    # Anthropic (Required)
    anthropic_api_key: Optional[str] = Field(
        None,
        alias="ANTHROPIC_API_KEY",
        description="Anthropic API key for Claude models"
    )

    gemini_api_key: Optional[str] = Field(
        None,
        alias="GOOGLE_API_KEY",
        description="Google API key for Gemini models"
    )

    # Google Maps (Required for Scout and Traffic agents)
    google_maps_api_key: Optional[str] = Field(
        None,
        alias="GOOGLE_MAPS_API_KEY",
        description="Google Maps Platform API key"
    )

    # OpenWeatherMap (Optional, for Weather agent)
    openweather_api_key: Optional[str] = Field(
        None,
        alias="OPENWEATHER_API_KEY",
        description="OpenWeatherMap API key (optional)"
    )

    # Mapbox (Optional, for UI visualization)
    mapbox_token: Optional[str] = Field(
        None,
        alias="MAPBOX_TOKEN",
        description="Mapbox access token for map visualization"
    )

    # ========================================================================
    # Model Configuration
    # ========================================================================

    # Claude model for agents and team
    model_name: str = Field(
        "claude-sonnet-4-20250514",
        alias="MODEL_NAME",
        description="Claude model name to use"
    )

    # Alternative models for cost optimization (future)
    planner_model: Optional[str] = Field(
        None,
        alias="PLANNER_MODEL",
        description="Specific model for Planner agent (optional)"
    )

    optimizer_model: Optional[str] = Field(
        None,
        alias="OPTIMIZER_MODEL",
        description="Specific model for Optimizer agent (optional)"
    )

    # ========================================================================
    # Application Settings
    # ========================================================================

    # Logging
    log_level: str = Field(
        "INFO",
        alias="LOG_LEVEL",
        description="Logging level (DEBUG/INFO/WARNING/ERROR)"
    )

    log_file: Optional[str] = Field(
        None,
        alias="LOG_FILE",
        description="Log file path (optional, logs to console if not set)"
    )

    # Search parameters
    poi_search_radius: int = Field(
        5000,
        alias="POI_SEARCH_RADIUS",
        description="Default POI search radius in meters"
    )

    max_poi_results: int = Field(
        5,
        alias="MAX_POI_RESULTS",
        description="Maximum number of POI candidates per task"
    )

    # Optimization parameters
    tsptw_time_limit: int = Field(
        10,
        alias="TSPTW_TIME_LIMIT",
        description="TSPTW solver time limit in seconds"
    )

    tsptw_verbose: bool = Field(
        False,
        alias="TSPTW_VERBOSE",
        description="Enable verbose output for TSPTW solver"
    )

    # Default locations
    default_start_lat: float = Field(
        25.0330,
        alias="DEFAULT_START_LAT",
        description="Default start location latitude (Taipei)"
    )

    default_start_lng: float = Field(
        121.5654,
        alias="DEFAULT_START_LNG",
        description="Default start location longitude (Taipei)"
    )

    # ========================================================================
    # Feature Flags
    # ========================================================================

    enable_weather_agent: bool = Field(
        True,
        alias="ENABLE_WEATHER_AGENT",
        description="Enable Weather agent (requires OpenWeatherMap API key)"
    )

    enable_traffic_agent: bool = Field(
        True,
        alias="ENABLE_TRAFFIC_AGENT",
        description="Enable Traffic agent (requires Google Maps API key)"
    )

    use_mock_data: bool = Field(
        False,
        alias="USE_MOCK_DATA",
        description="Use mock data instead of real APIs (for testing)"
    )

    TASK_LIST_KEY: str = Field("task_list", description="Session state key(name) for task list")

    # ========================================================================
    # Pydantic Config
    # ========================================================================

    class Config:
        env_file = str(Path(__file__).resolve().parents[2] / ".env")
        env_file_encoding = "utf-8"
        case_sensitive = False

        # Allow extra fields (for future extensions)
        extra = "ignore"


# ============================================================================
# Global Settings Instance
# ============================================================================

_settings: Optional[Settings] = None


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

    Returns:
        Settings: Application settings

    Raises:
        ValueError: If required environment variables are missing
    """
    global _settings

    if _settings is None:
        try:
            _settings = Settings()
        except Exception as e:
            raise ValueError(
                f"Failed to load settings. Please check your .env file or environment variables.\n"
                f"Error: {str(e)}\n\n"
                f"Required variables:\n"
                f"  - ANTHROPIC_API_KEY\n"
                f"  - GOOGLE_MAPS_API_KEY\n\n"
                f"Optional variables:\n"
                f"  - OPENWEATHER_API_KEY\n"
                f"  - MAPBOX_TOKEN\n"
            ) from e

    return _settings


def reload_settings():
    """
    Reload settings from environment

    Useful for testing or when environment variables change
    """
    global _settings
    _settings = None
    return get_settings()


# ============================================================================
# Logging Configuration
# ============================================================================

def setup_logging(settings: Optional[Settings] = None):
    """
    Setup application logging

    Args:
        settings: Settings instance (uses global if not provided)
    """
    if settings is None:
        settings = get_settings()

    # Configure logging format
    log_format = (
        "%(asctime)s - %(name)s - %(levelname)s - %(message)s"
    )

    # Configure handlers
    handlers = []

    # Console handler
    console_handler = logging.StreamHandler()
    console_handler.setFormatter(logging.Formatter(log_format))
    handlers.append(console_handler)

    # File handler (if specified)
    if settings.log_file:
        log_path = Path(settings.log_file)
        log_path.parent.mkdir(parents=True, exist_ok=True)

        file_handler = logging.FileHandler(settings.log_file)
        file_handler.setFormatter(logging.Formatter(log_format))
        handlers.append(file_handler)

    # Configure root logger
    logging.basicConfig(
        level=getattr(logging, settings.log_level.upper()),
        format=log_format,
        handlers=handlers
    )

    # Set specific loggers
    logging.getLogger("agno").setLevel(logging.WARNING)
    logging.getLogger("anthropic").setLevel(logging.WARNING)
    logging.getLogger("httpx").setLevel(logging.WARNING)

    logger = logging.getLogger(__name__)
    logger.info(f"Logging configured: level={settings.log_level}")

    if settings.log_file:
        logger.info(f"Logging to file: {settings.log_file}")


# ============================================================================
# Validation Helpers
# ============================================================================

def validate_api_keys(settings: Optional[Settings] = None) -> dict:
    """
    Validate that all required API keys are set

    Args:
        settings: Settings instance

    Returns:
        dict: Validation results
    """
    if settings is None:
        settings = get_settings()

    results = {
        "valid": True,
        "missing": [],
        "optional_missing": []
    }

    # Check required keys
    if not settings.anthropic_api_key:
        results["valid"] = False
        results["missing"].append("ANTHROPIC_API_KEY")

    if not settings.google_maps_api_key:
        results["valid"] = False
        results["missing"].append("GOOGLE_MAPS_API_KEY")

    # Check optional keys
    if settings.enable_weather_agent and not settings.openweather_api_key:
        results["optional_missing"].append("OPENWEATHER_API_KEY")

    if not settings.mapbox_token:
        results["optional_missing"].append("MAPBOX_TOKEN")

    return results


def print_config_status(settings: Optional[Settings] = None):
    """
    Print current configuration status

    Args:
        settings: Settings instance
    """
    if settings is None:
        settings = get_settings()

    print("=" * 60)
    print("📋 LifeFlow AI - Configuration Status")
    print("=" * 60)

    # API Keys
    print("\n🔑 API Keys:")
    print(f"  Anthropic:      {'✅ Set' if settings.anthropic_api_key else '❌ Missing'}")
    print(f"  Google Maps:    {'✅ Set' if settings.google_maps_api_key else '❌ Missing'}")
    print(f"  OpenWeatherMap: {'✅ Set' if settings.openweather_api_key else '⚠️  Not set (optional)'}")
    print(f"  Mapbox:         {'✅ Set' if settings.mapbox_token else '⚠️  Not set (optional)'}")

    # Model Configuration
    print("\n🤖 Model Configuration:")
    print(f"  Default Model:  {settings.model_name}")
    if settings.planner_model:
        print(f"  Planner Model:  {settings.planner_model}")
    if settings.optimizer_model:
        print(f"  Optimizer Model: {settings.optimizer_model}")

    # Application Settings
    print("\n⚙️  Application Settings:")
    print(f"  Log Level:      {settings.log_level}")
    print(f"  Log File:       {settings.log_file or 'Console only'}")
    print(f"  Search Radius:  {settings.poi_search_radius}m")
    print(f"  Max POI Results: {settings.max_poi_results}")
    print(f"  TSPTW Time Limit: {settings.tsptw_time_limit}s")

    # Feature Flags
    print("\n🎛️  Feature Flags:")
    print(f"  Weather Agent:  {'✅ Enabled' if settings.enable_weather_agent else '❌ Disabled'}")
    print(f"  Traffic Agent:  {'✅ Enabled' if settings.enable_traffic_agent else '❌ Disabled'}")
    print(f"  Mock Data Mode: {'⚠️  Enabled' if settings.use_mock_data else '✅ Disabled'}")

    # Validation
    validation = validate_api_keys(settings)
    print("\n✅ Validation:")
    if validation["valid"]:
        print("  All required API keys are set")
    else:
        print(f"  ❌ Missing required keys: {', '.join(validation['missing'])}")

    if validation["optional_missing"]:
        print(f"  ⚠️  Missing optional keys: {', '.join(validation['optional_missing'])}")

    print("=" * 60)


# ============================================================================
# Test
# ============================================================================

if __name__ == "__main__":
    try:
        settings = get_settings()
        print_config_status(settings)

        # Test validation
        validation = validate_api_keys(settings)

        if not validation["valid"]:
            print("\n❌ Configuration is invalid!")
            print("Please set the following environment variables:")
            for key in validation["missing"]:
                print(f"  - {key}")
        else:
            print("\n✅ Configuration is valid!")

    except Exception as e:
        print(f"\n❌ Error loading configuration:")
        print(f"  {str(e)}")
        print("\nPlease create a .env file with required variables.")
        raise e