package imagerequest

import (
	"crypto/sha256"
	"encoding/hex"
	"fmt"
)

// SourceKey is a SHA256 hash identifying a cached source image (hex-encoded).
type SourceKey string

// Key returns the key the source is cached under, made as CacheKey makes a
// variant key.
// Format: sha256(host:path:query)
// The path and query go through escapePercentAndColon, so that a ":" in
// either cannot be taken for the one between them.
func (s Source) Key() SourceKey {
	data := fmt.Sprintf("%s:%s:%s",
		s.Host,
		escapePercentAndColon(s.Path),
		escapePercentAndColon(s.Query),
	)
	h := sha256.Sum256([]byte(data))

	return SourceKey(hex.EncodeToString(h[:]))
}