"""
Configuration Loader
Loads and manages configuration from YAML files.
"""

import yaml
import os
from typing import Dict, Any, Optional
from dataclasses import dataclass


@dataclass
class AppConfig:
    """Application configuration."""
    title: str
    description: str
    theme: str
    server_host: str
    server_port: int
    server_share: bool


@dataclass
class LeaderboardConfig:
    """Leaderboard configuration."""
    path: str
    columns: list
    top_results: int
    results_table_headers: list


@dataclass
class MetricsConfig:
    """Metrics configuration."""
    weights: Dict[str, float]
    descriptions: Dict[str, str]
    thresholds: Dict[str, float]
    formatting: Dict[str, str]


@dataclass
class PromptsConfig:
    """Prompts configuration."""
    files: Dict[str, str]
    fallback: str
    placeholders: Dict[str, str]
    sections: Dict[str, str]


class ConfigLoader:
    """Loads and manages configuration from YAML files."""
    
    def __init__(self, config_dir: str = "config"):
        self.config_dir = config_dir
        self._app_config = None
        self._leaderboard_config = None
        self._metrics_config = None
        self._prompts_config = None
    
    def _load_yaml(self, filename: str) -> Dict[str, Any]:
        """Load a YAML configuration file."""
        filepath = os.path.join(self.config_dir, filename)
        if not os.path.exists(filepath):
            raise FileNotFoundError(f"Configuration file not found: {filepath}")
        
        with open(filepath, 'r') as f:
            return yaml.safe_load(f)
    
    def get_app_config(self) -> AppConfig:
        """Get application configuration."""
        if self._app_config is None:
            config = self._load_yaml("app.yaml")
            app = config["app"]
            server = app["server"]
            
            self._app_config = AppConfig(
                title=app["title"],
                description=app["description"],
                theme=app["theme"],
                server_host=server["host"],
                server_port=server["port"],
                server_share=server["share"]
            )
        
        return self._app_config
    
    def get_leaderboard_config(self) -> LeaderboardConfig:
        """Get leaderboard configuration."""
        if self._leaderboard_config is None:
            config = self._load_yaml("app.yaml")
            leaderboard = config["leaderboard"]
            display = leaderboard["display"]
            
            self._leaderboard_config = LeaderboardConfig(
                path=leaderboard["path"],
                columns=leaderboard["columns"],
                top_results=display["top_results"],
                results_table_headers=display["results_table_headers"]
            )
        
        return self._leaderboard_config
    
    def get_metrics_config(self) -> MetricsConfig:
        """Get metrics configuration."""
        if self._metrics_config is None:
            config = self._load_yaml("metrics.yaml")
            metrics = config["metrics"]
            
            self._metrics_config = MetricsConfig(
                weights=metrics["weights"],
                descriptions=metrics["descriptions"],
                thresholds=metrics["thresholds"],
                formatting=metrics["formatting"]
            )
        
        return self._metrics_config
    
    def get_prompts_config(self) -> PromptsConfig:
        """Get prompts configuration."""
        if self._prompts_config is None:
            config = self._load_yaml("prompts.yaml")
            prompts = config["prompts"]
            
            self._prompts_config = PromptsConfig(
                files=prompts["files"],
                fallback=prompts["fallback"],
                placeholders=prompts["placeholders"],
                sections=prompts["sections"]
            )
        
        return self._prompts_config
    
    def get_dialects(self) -> list:
        """Get available SQL dialects."""
        config = self._load_yaml("app.yaml")
        return config["dialects"]
    
    def get_ui_config(self) -> Dict[str, Any]:
        """Get UI configuration."""
        config = self._load_yaml("app.yaml")
        return config["ui"]
    
    def get_environment_config(self) -> Dict[str, Any]:
        """Get environment configuration."""
        config = self._load_yaml("app.yaml")
        return config["environment"]
    
    def get_mock_sql_config(self) -> Dict[str, Any]:
        """Get mock SQL configuration."""
        config = self._load_yaml("metrics.yaml")
        return config["mock_sql"]
    
    def get_visible_datasets(self) -> list:
        """Get list of visible datasets from configuration."""
        config = self._load_yaml("app.yaml")
        return config.get("visible_datasets", [])


# Global configuration loader instance
config_loader = ConfigLoader()