package config

import (
	"fmt"
	"log/slog"
	"os"
	"strings"
)

type Config struct {
	HTTPAddress     string
	WebRoot         string
	StorageRoot     string
	PreviewCacheDir string
	DatabaseURL     string
	LogLevel        slog.Level
}

func FromEnvironment() (Config, error) {
	level, err := parseLogLevel(environment("DRIVE_LOG_LEVEL", "info"))
	if err != nil {
		return Config{}, err
	}

	return Config{
		HTTPAddress:     environment("DRIVE_HTTP_ADDRESS", ":8080"),
		WebRoot:         environment("DRIVE_WEB_ROOT", "web/dist"),
		StorageRoot:     environment("DRIVE_STORAGE_ROOT", "/storage/.drive"),
		PreviewCacheDir: environment("DRIVE_PREVIEW_CACHE_ROOT", "/cache/previews"),
		DatabaseURL:     os.Getenv("DRIVE_DATABASE_URL"),
		LogLevel:        level,
	}, nil
}

func environment(name, fallback string) string {
	if value := strings.TrimSpace(os.Getenv(name)); value != "" {
		return value
	}
	return fallback
}

func parseLogLevel(value string) (slog.Level, error) {
	switch strings.ToLower(value) {
	case "debug":
		return slog.LevelDebug, nil
	case "info":
		return slog.LevelInfo, nil
	case "warn", "warning":
		return slog.LevelWarn, nil
	case "error":
		return slog.LevelError, nil
	default:
		return 0, fmt.Errorf("invalid DRIVE_LOG_LEVEL %q", value)
	}
}