#!/usr/bin/env python3
"""Configuration helper for py-wikijs.

This module provides utilities to load configuration from various sources:
- Environment variables (.env files)
- YAML files
- JSON files
- INI files
- Python dictionaries

Usage:
    from config_helper import load_config, create_client_from_config

    # Load config from file
    config = load_config('config.yaml')

    # Create client from config
    client = create_client_from_config(config)

    # Or use auto-detection
    client = create_client_from_config()  # Searches for config files
"""

import json
import logging
import os
from configparser import ConfigParser
from pathlib import Path
from typing import Any, Dict, Optional, Union

# Optional dependencies
try:
    import yaml

    YAML_AVAILABLE = True
except ImportError:
    YAML_AVAILABLE = False

try:
    from dotenv import load_dotenv

    DOTENV_AVAILABLE = True
except ImportError:
    DOTENV_AVAILABLE = False


class ConfigLoader:
    """Load configuration from various sources."""

    def __init__(self, config_dir: Optional[str] = None):
        """Initialize config loader.

        Args:
            config_dir: Directory to search for config files (default: current dir)
        """
        self.config_dir = Path(config_dir) if config_dir else Path.cwd()

    def load_env(self, env_file: Optional[str] = None) -> Dict[str, Any]:
        """Load configuration from environment variables.

        Args:
            env_file: Path to .env file (optional)

        Returns:
            Configuration dictionary
        """
        # Load .env file if available
        if env_file and DOTENV_AVAILABLE:
            load_dotenv(env_file)
        elif DOTENV_AVAILABLE:
            # Try to find .env in config directory
            env_path = self.config_dir / ".env"
            if env_path.exists():
                load_dotenv(env_path)

        config = {
            "wikijs": {
                "url": os.getenv("WIKIJS_URL"),
                "auth": {
                    "method": os.getenv("WIKIJS_AUTH_METHOD", "api_key"),
                    "api_key": os.getenv("WIKIJS_API_KEY"),
                    "jwt_token": os.getenv("WIKIJS_JWT_TOKEN"),
                },
            },
            "client": {
                "timeout": float(os.getenv("WIKIJS_TIMEOUT", "30.0")),
                "rate_limit": (
                    float(os.getenv("WIKIJS_RATE_LIMIT"))
                    if os.getenv("WIKIJS_RATE_LIMIT")
                    else None
                ),
                "max_retries": int(os.getenv("WIKIJS_MAX_RETRIES", "3")),
                "verify_ssl": os.getenv("WIKIJS_VERIFY_SSL", "true").lower()
                == "true",
                "pool_size": int(os.getenv("WIKIJS_POOL_SIZE", "10")),
                "user_agent": os.getenv("WIKIJS_USER_AGENT"),
            },
            "logging": {
                "debug": os.getenv("WIKIJS_DEBUG", "false").lower() == "true",
                "level": os.getenv("WIKIJS_LOG_LEVEL", "INFO"),
            },
            "metrics": {
                "enabled": os.getenv("WIKIJS_ENABLE_METRICS", "true").lower()
                == "true",
            },
        }

        # Remove None values
        return self._clean_dict(config)

    def load_yaml(self, yaml_file: Union[str, Path]) -> Dict[str, Any]:
        """Load configuration from YAML file.

        Args:
            yaml_file: Path to YAML file

        Returns:
            Configuration dictionary

        Raises:
            ImportError: If PyYAML is not installed
        """
        if not YAML_AVAILABLE:
            raise ImportError(
                "PyYAML is required for YAML config files. "
                "Install with: pip install pyyaml"
            )

        yaml_path = Path(yaml_file)
        if not yaml_path.is_absolute():
            yaml_path = self.config_dir / yaml_path

        with open(yaml_path, "r", encoding="utf-8") as f:
            return yaml.safe_load(f)

    def load_json(self, json_file: Union[str, Path]) -> Dict[str, Any]:
        """Load configuration from JSON file.

        Args:
            json_file: Path to JSON file

        Returns:
            Configuration dictionary
        """
        json_path = Path(json_file)
        if not json_path.is_absolute():
            json_path = self.config_dir / json_path

        with open(json_path, "r", encoding="utf-8") as f:
            return json.load(f)

    def load_ini(self, ini_file: Union[str, Path]) -> Dict[str, Any]:
        """Load configuration from INI file.

        Args:
            ini_file: Path to INI file

        Returns:
            Configuration dictionary
        """
        ini_path = Path(ini_file)
        if not ini_path.is_absolute():
            ini_path = self.config_dir / ini_path

        parser = ConfigParser()
        parser.read(ini_path)

        config: Dict[str, Any] = {}

        # Convert INI sections to nested dict
        for section in parser.sections():
            section_dict: Dict[str, Any] = {}
            for key, value in parser.items(section):
                # Convert string values to appropriate types
                section_dict[key] = self._parse_value(value)

            # Handle nested sections (e.g., cache.redis)
            if "." in section:
                parent, child = section.split(".", 1)
                if parent not in config:
                    config[parent] = {}
                config[parent][child] = section_dict
            else:
                config[section] = section_dict

        # Restructure for consistency with other formats
        if "wikijs" in config:
            config["wikijs"]["auth"] = {
                "method": config["wikijs"].pop("auth_method", "api_key"),
                "api_key": config["wikijs"].pop("api_key", None),
                "jwt_token": config["wikijs"].pop("jwt_token", None),
            }

        if "logging" in config:
            if "file_enabled" in config["logging"]:
                config["logging"]["file"] = {
                    "enabled": config["logging"].pop("file_enabled"),
                    "path": config["logging"].pop("file_path", None),
                    "max_bytes": config["logging"].pop("file_max_bytes", None),
                    "backup_count": config["logging"].pop("file_backup_count", None),
                }

        return self._clean_dict(config)

    def auto_load(self) -> Dict[str, Any]:
        """Auto-detect and load configuration from available sources.

        Searches for config files in this order:
        1. .env file
        2. config.yaml
        3. config.yml
        4. config.json
        5. config.ini

        Returns:
            Configuration dictionary

        Raises:
            FileNotFoundError: If no config file is found
        """
        # Try .env
        env_path = self.config_dir / ".env"
        if env_path.exists():
            return self.load_env(env_path)

        # Try YAML
        for yaml_name in ["config.yaml", "config.yml"]:
            yaml_path = self.config_dir / yaml_name
            if yaml_path.exists():
                return self.load_yaml(yaml_path)

        # Try JSON
        json_path = self.config_dir / "config.json"
        if json_path.exists():
            return self.load_json(json_path)

        # Try INI
        ini_path = self.config_dir / "config.ini"
        if ini_path.exists():
            return self.load_ini(ini_path)

        raise FileNotFoundError(
            f"No configuration file found in {self.config_dir}. "
            "Tried: .env, config.yaml, config.yml, config.json, config.ini"
        )

    def _parse_value(self, value: str) -> Any:
        """Parse string value to appropriate type."""
        # Boolean
        if value.lower() in ("true", "yes", "1", "on"):
            return True
        if value.lower() in ("false", "no", "0", "off"):
            return False

        # None/null
        if value.lower() in ("none", "null", ""):
            return None

        # Number
        try:
            if "." in value:
                return float(value)
            return int(value)
        except ValueError:
            pass

        # String
        return value

    def _clean_dict(self, d: Dict[str, Any]) -> Dict[str, Any]:
        """Remove None values from nested dictionary."""
        cleaned = {}
        for key, value in d.items():
            if isinstance(value, dict):
                nested = self._clean_dict(value)
                if nested:  # Only add if not empty
                    cleaned[key] = nested
            elif value is not None:
                cleaned[key] = value
        return cleaned


def load_config(
    source: Optional[Union[str, Path, Dict[str, Any]]] = None,
    config_dir: Optional[str] = None,
) -> Dict[str, Any]:
    """Load configuration from a source.

    Args:
        source: Config source (file path, dict, or None for auto-detection)
        config_dir: Directory to search for config files

    Returns:
        Configuration dictionary

    Examples:
        >>> config = load_config('config.yaml')
        >>> config = load_config('.env')
        >>> config = load_config()  # Auto-detect
        >>> config = load_config({'wikijs': {'url': '...'}})
    """
    loader = ConfigLoader(config_dir)

    # If source is a dict, return it directly
    if isinstance(source, dict):
        return source

    # If source is provided, load it
    if source:
        source_path = Path(source)

        # Determine file type by extension
        suffix = source_path.suffix.lower()

        if suffix in [".yaml", ".yml"]:
            return loader.load_yaml(source)
        elif suffix == ".json":
            return loader.load_json(source)
        elif suffix == ".ini":
            return loader.load_ini(source)
        elif suffix == ".env" or source_path.name == ".env":
            return loader.load_env(source)
        else:
            raise ValueError(f"Unknown config file type: {suffix}")

    # Auto-detect
    return loader.auto_load()


def create_client_from_config(
    config: Optional[Union[str, Path, Dict[str, Any]]] = None,
    **kwargs: Any,
) -> Any:
    """Create WikiJSClient from configuration.

    Args:
        config: Config source (file path, dict, or None for auto-detection)
        **kwargs: Additional arguments to override config values

    Returns:
        Configured WikiJSClient instance

    Examples:
        >>> client = create_client_from_config('config.yaml')
        >>> client = create_client_from_config()  # Auto-detect
        >>> client = create_client_from_config(timeout=60.0)  # Override
    """
    from wikijs import WikiJSClient

    # Load configuration
    if config is None:
        # Try to auto-load, fall back to env vars
        try:
            cfg = load_config()
        except FileNotFoundError:
            cfg = ConfigLoader().load_env()
    else:
        cfg = load_config(config)

    # Extract Wiki.js settings
    wikijs_cfg = cfg.get("wikijs", {})
    url = kwargs.pop("url", wikijs_cfg.get("url"))

    if not url:
        raise ValueError("Wiki.js URL is required (set WIKIJS_URL or in config file)")

    # Determine auth
    auth_cfg = wikijs_cfg.get("auth", {})
    auth_method = auth_cfg.get("method", "api_key")

    if "auth" not in kwargs:
        if auth_method == "api_key":
            auth = auth_cfg.get("api_key")
            if not auth:
                raise ValueError(
                    "API key is required (set WIKIJS_API_KEY or in config file)"
                )
        elif auth_method == "jwt":
            auth = auth_cfg.get("jwt_token")
            if not auth:
                raise ValueError(
                    "JWT token is required (set WIKIJS_JWT_TOKEN or in config file)"
                )
        else:
            auth = None
    else:
        auth = kwargs.pop("auth")

    # Extract client settings
    client_cfg = cfg.get("client", {})
    timeout = kwargs.pop("timeout", client_cfg.get("timeout", 30.0))
    rate_limit = kwargs.pop("rate_limit", client_cfg.get("rate_limit"))
    max_retries = kwargs.pop("max_retries", client_cfg.get("max_retries", 3))
    verify_ssl = kwargs.pop("verify_ssl", client_cfg.get("verify_ssl", True))

    # Extract logging settings
    logging_cfg = cfg.get("logging", {})
    log_level_str = kwargs.pop("log_level", logging_cfg.get("level", "INFO"))

    # Convert log level string to logging constant
    log_level = getattr(logging, log_level_str.upper(), logging.INFO)

    # Create client
    client = WikiJSClient(
        url=url,
        auth=auth,
        timeout=timeout,
        rate_limit=rate_limit,
        max_retries=max_retries,
        verify_ssl=verify_ssl,
        log_level=log_level,
        **kwargs,
    )

    return client


def validate_config(config: Dict[str, Any]) -> bool:
    """Validate configuration dictionary.

    Args:
        config: Configuration dictionary

    Returns:
        True if valid

    Raises:
        ValueError: If configuration is invalid
    """
    # Check required fields
    if "wikijs" not in config:
        raise ValueError("Missing 'wikijs' section in config")

    wikijs = config["wikijs"]

    if "url" not in wikijs:
        raise ValueError("Missing 'wikijs.url' in config")

    # Validate URL format
    url = wikijs["url"]
    if not url.startswith(("http://", "https://")):
        raise ValueError(f"Invalid URL format: {url}")

    # Check auth
    if "auth" in wikijs:
        auth = wikijs["auth"]
        method = auth.get("method", "api_key")

        if method == "api_key" and not auth.get("api_key"):
            raise ValueError("Missing API key for api_key auth method")

        if method == "jwt" and not auth.get("jwt_token"):
            raise ValueError("Missing JWT token for jwt auth method")

    return True


if __name__ == "__main__":
    # Example usage
    print("🔧 py-wikijs Configuration Helper\n")

    try:
        # Try to load config
        config = load_config()
        print(f"✅ Loaded configuration from auto-detected source")
        print(f"\nConfiguration:")
        print(json.dumps(config, indent=2))

        # Validate
        validate_config(config)
        print("\n✅ Configuration is valid")

        # Create client
        client = create_client_from_config(config)
        print(f"\n✅ Created WikiJSClient")
        print(f"   URL: {client.base_url}")

    except FileNotFoundError as e:
        print(f"❌ {e}")
        print("\nℹ️  Create a config file from one of the examples:")
        print("   - config.env.example → .env")
        print("   - config.yaml.example → config.yaml")
        print("   - config.json.example → config.json")
        print("   - config.ini.example → config.ini")

    except Exception as e:
        print(f"❌ Error: {e}")