package types

import (
	"fmt"
	"regexp"
	"strings"
)

var (
	idRegex = regexp.MustCompile(`(.*?)(@(.*))?:(.*)`)
)

// ID an id of a file consists of at least a Bucket and a Key. Version is optional.
// Can also be used as an ID for a directory. When the key ends with "/" it is treated as dir.
type ID struct {
	Bucket  string // Name of the bucket
	Key     string // Key of the object
	Version string // Version of the object. For now we ignore it
}

// String Return String representation of an ID
// Looks like this: "bucketName@version:/id/of/obj" or "bucketName:/id/of/obj"
func (i *ID) String() string {
	i.Normalize()
	if i.Version == "" {
		return fmt.Sprintf("%s:%s", i.Bucket, i.Key)
	} else {
		return fmt.Sprintf("%s@%s:%s", i.Bucket, i.Version, i.Key)
	}
}

// Normalize normalzes the key to have a "/" prefix
func (i *ID) Normalize() {
	if !strings.HasPrefix(i.Key, "/") {
		i.Key = "/" + i.Key
	}
}

// Valid checks if bucket and key is not empty
func (i *ID) Valid() bool {
	return i.Bucket != "" && i.Key != ""
}

// ParseID parses a string to an ID. Null if invalid
func ParseID(id string) *ID {
	match := idRegex.FindStringSubmatch(id)
	if match == nil {
		return nil
	}

	rtn := &ID{
		Bucket:  match[1],
		Version: match[3],
		Key:     match[4],
	}

	if !rtn.Valid() {
		return nil
	}

	rtn.Normalize()

	return rtn
}