"""
Centralized path resolution for Basecamp MCP Server.

All paths can be overridden via environment variables.
"""

import os
from pathlib import Path


def get_log_directory() -> Path:
    """
    Get the directory for log files.

    Priority order:
    1. BASECAMP_LOG_DIR env variable
    2. XDG_STATE_HOME (typically ~/.local/state)
    3. ~/.local/state/basecamp-mcp (fallback)
    """
    if log_dir := os.getenv("BASECAMP_LOG_DIR"):
        return Path(log_dir)

    if xdg_state := os.getenv("XDG_STATE_HOME"):
        return Path(xdg_state) / "basecamp-mcp"

    return Path.home() / ".local/state/basecamp-mcp"


def get_config_directory() -> Path:
    """
    Get the directory for configuration files (.env).

    Priority order:
    1. BASECAMP_CONFIG_DIR env variable
    2. XDG_CONFIG_HOME (typically ~/.config)
    3. ~/.config/basecamp-mcp (fallback)

    NOTE: This is only used if BASECAMP_ENV_FILE is not set and
    a .env file exists in the config directory. The server works
    entirely with environment variables and doesn't require .env files.
    """
    if config_dir := os.getenv("BASECAMP_CONFIG_DIR"):
        return Path(config_dir)

    if xdg_config := os.getenv("XDG_CONFIG_HOME"):
        return Path(xdg_config) / "basecamp-mcp"

    return Path.home() / ".config/basecamp-mcp"


def get_env_file_path() -> Path:
    """
    Get the path for .env file (optional).

    Priority order:
    1. BASECAMP_ENV_FILE env variable (explicitly specified)
    2. Config directory + / .env

    The server does NOT require this file - it's optional.
    If not found, environment will be used as-is.
    """
    if env_file := os.getenv("BASECAMP_ENV_FILE"):
        return Path(env_file)

    return get_config_directory() / ".env"


def get_token_file_path() -> Path:
    """
    Get the path for OAuth token storage.

    Priority order:
    1. BASECAMP_TOKEN_FILE env variable
    2. XDG_DATA_HOME (typically ~/.local/share)
    3. ~/.local/share/basecamp-mcp/oauth_tokens.json (fallback)
    """
    if token_file := os.getenv("BASECAMP_TOKEN_FILE"):
        return Path(token_file)

    if xdg_data := os.getenv("XDG_DATA_HOME"):
        return Path(xdg_data) / "basecamp-mcp" / "oauth_tokens.json"

    return Path.home() / ".local/share/basecamp-mcp" / "oauth_tokens.json"


def ensure_directories_exist() -> None:
    """
    Create all necessary directories if they don't exist.
    """
    get_log_directory().mkdir(parents=True, exist_ok=True)
    get_config_directory().mkdir(parents=True, exist_ok=True)
    get_token_file_path().parent.mkdir(parents=True, exist_ok=True)