package client

import (
	"crypto/sha256"
	"crypto/sha512"
	"encoding/hex"
        "strings"
)

func SHA256Digest(src []byte) string {
	hasher := sha256.New()
	hasher.Write(src)
	sum := hasher.Sum(nil)
	return "sha256:" + hex.EncodeToString(sum)
}

func SHA512Digest(src []byte) string {
	hasher := sha512.New()
	hasher.Write(src)
	sum := hasher.Sum(nil)
	return "sha512:" + hex.EncodeToString(sum)
}

const (
        Undefined int = iota
        SHA256
        SHA512
)


func DigestType(digest string) int {
        var err error
        var typ int
        digest = strings.ToLower(digest)
        digest = strings.TrimPrefix(digest, "sha256:")
        digest = strings.TrimPrefix(digest, "sha512:")
        decoded, err := hex.DecodeString(digest)
        if err != nil {
                        return Undefined
        }
        switch (len(decoded)) {
                case 64:
                        typ = SHA256
                case 128:
                        typ = SHA512
                default:
                        typ = Undefined
        }
        return typ
}