"""Configuration management for local-commit-message-generator."""

import os
from pathlib import Path
from typing import Any, Dict, Optional

import tomlkit


class ConfigError(Exception):
    """Raised when configuration errors occur."""
    pass


DEFAULT_TYPE_RULES: Dict[str, list[str]] = {
    "feat": ["src/", "lib/", "app/", "controllers/", "models/"],
    "fix": ["src/", "lib/", "bug", "fix", "issue", "hotfix"],
    "docs": [".md", ".rst", "docs/", "documentation/"],
    "style": [".css", ".scss", ".sass", ".less", "styles/"],
    "refactor": ["refactor/", "rewrite/", "restructure/"],
    "test": ["test/", "tests/", "__tests__/", ".test.", ".spec."],
    "chore": ["package.json", "pyproject.toml", "requirements", ".gitignore", "Makefile"],
    "perf": ["performance/", "perf/", "optimize/", "optimization/"],
    "ci": [".github/", ".gitlab-ci.yml", ".travis.yml", "Jenkinsfile", "tox.ini"],
    "build": ["build/", "webpack/", "vite.config", "babel.config", "rollup.config"],
}

DEFAULT_CONFIG: Dict[str, Any] = {
    "type_rules": DEFAULT_TYPE_RULES,
    "template": "{type}{scope}: {description}",
    "scopes": {},
    "description_length": 72,
    "max_files": 5,
    "include_file_list": True,
    "file_list_template": "\n\nFiles changed:\n{files}",
}


def get_config_path() -> Path:
    """Get the path to the user configuration file."""
    home = Path.home()
    return home / ".local_commit_gen.toml"


def load_config(config_path: Optional[Path] = None) -> Dict[str, Any]:
    """Load configuration from file.

    Args:
        config_path: Optional path to config file. If not provided, uses default path.

    Returns:
        Dictionary containing configuration.
    """
    if config_path is None:
        config_path = get_config_path()

    if not config_path.exists():
        return DEFAULT_CONFIG.copy()

    try:
        with open(config_path, "r") as f:
            config = tomlkit.parse(f.read())
    except tomlkit.exceptions.ParseError as e:
        raise ConfigError(f"Invalid TOML syntax in config file: {e}")

    merged = DEFAULT_CONFIG.copy()
    for key, value in config.items():
        if key == "type_rules" and isinstance(value, dict):
            merged["type_rules"] = {**DEFAULT_TYPE_RULES, **value}
        else:
            merged[key] = value

    return merged


def save_config(config: Dict[str, Any], config_path: Optional[Path] = None) -> None:
    """Save configuration to file.

    Args:
        config: Configuration dictionary to save.
        config_path: Optional path to config file. If not provided, uses default path.
    """
    if config_path is None:
        config_path = get_config_path()

    try:
        with open(config_path, "w") as f:
            tomlkit.dump(config, f)
    except OSError as e:
        raise ConfigError(f"Failed to write config file: {e}")


def ensure_config_exists() -> None:
    """Ensure default config file exists."""
    config_path = get_config_path()
    if not config_path.exists():
        save_config(DEFAULT_CONFIG.copy())


def get_type_rules(config: Optional[Dict[str, Any]] = None) -> Dict[str, list[str]]:
    """Get type rules from configuration.

    Args:
        config: Optional configuration dictionary. If not provided, loads from file.

    Returns:
        Dictionary mapping commit types to patterns.
    """
    if config is None:
        config = load_config()
    return config.get("type_rules", DEFAULT_TYPE_RULES)


def get_template(config: Optional[Dict[str, Any]] = None) -> str:
    """Get message template from configuration.

    Args:
        config: Optional configuration dictionary. If not provided, loads from file.

    Returns:
        Message template string.
    """
    if config is None:
        config = load_config()
    return config.get("template", DEFAULT_CONFIG["template"])