/*
godlighty -- highly-customizable HTTP, HTTP/2, HTTPS server
Copyright (C) 2021-2023 Sergey Matveev <stargrave@stargrave.org>

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, version 3 of the License.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

package meta4

import (
	"encoding/hex"
	"encoding/xml"
)

type ForHTTP struct {
	SHA256      []byte
	SHA512      []byte
	Streebog256 []byte
	Streebog512 []byte
	SHAKE128    []byte
	SHAKE256    []byte
	URLs        []string
}

func Parse(fn string, data []byte) (*ForHTTP, error) {
	var meta Metalink
	err := xml.Unmarshal(data, &meta)
	if err != nil {
		return nil, err
	}
	for _, f := range meta.Files {
		if f.Name != fn {
			continue
		}
		forHTTP := ForHTTP{}
		for _, h := range f.Hashes {
			digest, err := hex.DecodeString(h.Hash)
			if err != nil {
				return nil, err
			}
			switch h.Type {
			case HashSHA256:
				forHTTP.SHA256 = digest
			case HashSHA512:
				forHTTP.SHA512 = digest
			case HashStreebog256:
				forHTTP.Streebog256 = digest
			case HashStreebog512:
				forHTTP.Streebog512 = digest
			case HashSHAKE128:
				forHTTP.SHAKE128 = digest
			case HashSHAKE256:
				forHTTP.SHAKE256 = digest
			}
		}
		for _, u := range f.URLs {
			forHTTP.URLs = append(forHTTP.URLs, u.URL)
		}
		return &forHTTP, nil
	}
	return nil, nil
}