/*
 *     Copyright 2020 The Dragonfly Authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package idgen

import (
	"hash/crc32"
	"strings"

	"d7y.io/dragonfly/v2/pkg/rpc/base"
	"d7y.io/dragonfly/v2/pkg/util/digestutils"
	"d7y.io/dragonfly/v2/pkg/util/net/urlutils"
)

const (
	TwinsASuffix = "_A"
	TwinsBSuffix = "_B"
)

// GenerateTaskID generates a taskId.
// filter is separated by & character.
func TaskID(url string, filter string, meta *base.UrlMeta, bizID string) string {
	var data []string

	data = append(data, urlutils.FilterURLParam(url, strings.Split(filter, "&")))

	if meta != nil {
		if meta.Digest != "" {
			data = append(data, meta.Digest)
		}

		if meta.Range != "" {
			data = append(data, meta.Range)
		}
	}

	if bizID != "" {
		data = append(data, bizID)
	}

	return digestutils.Sha256(data...)
}

// GenerateTwinsTaskId used A/B testing
func TwinsTaskID(url string, filter string, meta *base.UrlMeta, bizID, peerID string) string {
	taskID := TaskID(url, filter, meta, bizID)

	if crc32.ChecksumIEEE([]byte(peerID))&1 == 0 {
		taskID += TwinsASuffix
	} else {
		taskID += TwinsBSuffix
	}

	return taskID
}