package settings

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"
)

const (
	DefaultConfigDir = "/etc/ClusterCanvas"
	ConfigDirEnvVar  = "CLUSTERCANVAS_CONFIG_DIR"
	ConfigKeyEnvVar  = "CLUSTERCANVAS_CONFIG_KEY"

	SettingsFileName  = "settings.json"
	SecretsFileName   = "secrets.enc"
	PasswordsFileName = "passwords.enc"
	SessionsFileName  = "sessions.enc"
)

// ResolveDir returns the config directory using precedence:
// 1. flagValue (-configdir), if non-empty
// 2. CLUSTERCANVAS_CONFIG_DIR, if set
// 3. /etc/ClusterCanvas
//
// Leading ~/ is expanded to the user home directory.
func ResolveDir(flagValue string) (string, error) {
	candidate := strings.TrimSpace(flagValue)
	if candidate == "" {
		candidate = strings.TrimSpace(os.Getenv(ConfigDirEnvVar))
	}
	if candidate == "" {
		candidate = DefaultConfigDir
	}

	expanded, err := expandHome(candidate)
	if err != nil {
		return "", err
	}
	return filepath.Clean(expanded), nil
}

func expandHome(path string) (string, error) {
	if path == "~" {
		homeDirectory, err := os.UserHomeDir()
		if err != nil {
			return "", fmt.Errorf("expand home directory: %w", err)
		}
		return homeDirectory, nil
	}
	if strings.HasPrefix(path, "~/") {
		homeDirectory, err := os.UserHomeDir()
		if err != nil {
			return "", fmt.Errorf("expand home directory: %w", err)
		}
		return filepath.Join(homeDirectory, path[2:]), nil
	}
	return path, nil
}

func ensureConfigDir(dir string) error {
	if err := os.MkdirAll(dir, 0o750); err != nil {
		return fmt.Errorf("create config dir %q: %w", dir, err)
	}
	return nil
}