vaultik/internal/storage/url.go

package storage

import (
	"errors"
	"fmt"
	"net/url"
	"strings"
)

// Storage URL scheme names.
const (
	schemeFile   = "file"
	schemeS3     = "s3"
	schemeRclone = "rclone"
)

// Sentinel errors for storage URL parsing.
var (
	ErrEmptyStorageURL   = errors.New("storage URL is empty")
	ErrEmptyFilePath     = errors.New("file URL path is empty")
	ErrMissingBucket     = errors.New("s3 URL missing bucket name")
	ErrMissingRemote     = errors.New("rclone URL missing remote name")
	ErrUnsupportedScheme = errors.New(
		"unsupported URL scheme: must start with s3://, file://, or rclone://")
	ErrUnsupportedStorage = errors.New("unsupported storage scheme")
)

// URL represents a parsed storage URL.
type URL struct {
	Scheme       string // "s3", "file", or "rclone"
	Bucket       string // S3 bucket name (empty for file/rclone)
	Prefix       string // Path within bucket or filesystem base path
	Endpoint     string // S3 endpoint (optional, default AWS)
	Region       string // S3 region (optional)
	UseSSL       bool   // Use HTTPS for S3 (default true)
	RcloneRemote string // rclone remote name (for rclone:// URLs)
}

// ParseStorageURL parses a storage URL string.
// Supported formats:
//   - s3://bucket/prefix?endpoint=host&region=us-east-1&ssl=true
//   - file:///absolute/path/to/backup
//   - rclone://remote/path/to/backups
func ParseStorageURL(rawURL string) (*URL, error) {
	if rawURL == "" {
		return nil, ErrEmptyStorageURL
	}

	// Handle file:// URLs
	if after, ok := strings.CutPrefix(rawURL, "file://"); ok {
		path := after
		if path == "" {
			return nil, ErrEmptyFilePath
		}

		return &URL{
			Scheme: schemeFile,
			Prefix: path,
		}, nil
	}

	// Handle s3:// URLs
	if strings.HasPrefix(rawURL, "s3://") {
		u, err := url.Parse(rawURL)
		if err != nil {
			return nil, fmt.Errorf("invalid URL: %w", err)
		}

		bucket := u.Host
		if bucket == "" {
			return nil, ErrMissingBucket
		}

		prefix := strings.TrimPrefix(u.Path, "/")

		query := u.Query()

		useSSL := true
		if query.Get("ssl") == "false" {
			useSSL = false
		}

		return &URL{
			Scheme:   schemeS3,
			Bucket:   bucket,
			Prefix:   prefix,
			Endpoint: query.Get("endpoint"),
			Region:   query.Get("region"),
			UseSSL:   useSSL,
		}, nil
	}

	// Handle rclone:// URLs
	if strings.HasPrefix(rawURL, "rclone://") {
		u, err := url.Parse(rawURL)
		if err != nil {
			return nil, fmt.Errorf("invalid URL: %w", err)
		}

		remote := u.Host
		if remote == "" {
			return nil, ErrMissingRemote
		}

		path := strings.TrimPrefix(u.Path, "/")

		return &URL{
			Scheme:       schemeRclone,
			Prefix:       path,
			RcloneRemote: remote,
		}, nil
	}

	return nil, ErrUnsupportedScheme
}

// String returns a human-readable representation of the storage URL.
func (u *URL) String() string {
	switch u.Scheme {
	case schemeFile:
		return "file://" + u.Prefix
	case schemeS3:
		endpoint := u.Endpoint
		if endpoint == "" {
			endpoint = "s3.amazonaws.com"
		}

		if u.Prefix != "" {
			return fmt.Sprintf("s3://%s/%s (endpoint: %s)", u.Bucket, u.Prefix, endpoint)
		}

		return fmt.Sprintf("s3://%s (endpoint: %s)", u.Bucket, endpoint)
	case schemeRclone:
		if u.Prefix != "" {
			return fmt.Sprintf("rclone://%s/%s", u.RcloneRemote, u.Prefix)
		}

		return "rclone://" + u.RcloneRemote
	default:
		return u.Scheme + "://?"
	}
}