/*
 * SPDX-FileCopyrightText: 2023 jordi fita mas <jfita@peritasoft.com>
 * SPDX-License-Identifier: AGPL-3.0-only
 */

package uuid

import (
	gohex "encoding/hex"
	"fmt"

	"dev.tandem.ws/tandem/camper/pkg/hex"
)

func Valid(s string) bool {
	if len(s) != 36 {
		return false
	}
	// it must be of the form  xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
	if s[8] != '-' || s[13] != '-' || s[18] != '-' || s[23] != '-' {
		return false
	}
	for _, x := range [16]int{
		0, 2, 4, 6,
		9, 11,
		14, 16,
		19, 21,
		24, 26, 28, 30, 32, 34} {
		if !hex.Valid(s[x], s[x+1]) {
			return false
		}
	}
	return true
}

func Parse(src string) (dst [16]byte, err error) {
	switch len(src) {
	case 36:
		src = src[0:8] + src[9:13] + src[14:18] + src[19:23] + src[24:]
	case 32:
		// dashes already stripped, assume valid
	default:
		// assume invalid.
		return dst, fmt.Errorf("cannot parse UUID %v", src)
	}

	buf, err := gohex.DecodeString(src)
	if err != nil {
		return dst, err
	}

	copy(dst[:], buf)
	return dst, err
}