/*
   Copyright (c) 2016 VMware, Inc. All Rights Reserved.
   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 cache

import (
	"os"
	"time"

	"github.com/vmware/harbor/utils/log"
	"github.com/vmware/harbor/utils/registry"

	"github.com/astaxie/beego/cache"
)

var (
	// Cache is the global cache in system.
	Cache             cache.Cache
	endpoint          string
	username          string
	registryClient    *registry.Registry
	repositoryClients map[string]*registry.Repository
)

const catalogKey string = "catalog"

func init() {
	var err error
	Cache, err = cache.NewCache("memory", `{"interval":720}`)
	if err != nil {
		log.Errorf("Failed to initialize cache, error:%v", err)
	}

	endpoint = os.Getenv("REGISTRY_URL")
	username = "admin"
	repositoryClients = make(map[string]*registry.Repository, 10)
}

// RefreshCatalogCache calls registry's API to get repository list and write it to cache.
func RefreshCatalogCache() error {
	log.Debug("refreshing catalog cache...")

	if registryClient == nil {
		var err error
		registryClient, err = registry.NewRegistryWithUsername(endpoint, username)
		if err != nil {
			log.Errorf("error occurred while initializing registry client used by cache: %v", err)
			return err
		}
	}

	var err error
	rs, err := registryClient.Catalog()
	if err != nil {
		return err
	}

	repos := []string{}

	for _, repo := range rs {
		rc, ok := repositoryClients[repo]
		if !ok {
			rc, err = registry.NewRepositoryWithUsername(repo, endpoint, username)
			if err != nil {
				log.Errorf("error occurred while initializing repository client used by cache: %s %v", repo, err)
				continue
			}
			repositoryClients[repo] = rc
		}
		tags, err := rc.ListTag()
		if err != nil {
			log.Errorf("error occurred while list tag for %s: %v", repo, err)
			continue
		}

		if len(tags) != 0 {
			repos = append(repos, repo)
			log.Debugf("add %s to catalog cache", repo)
		}
	}

	Cache.Put(catalogKey, repos, 600*time.Second)
	return nil
}

// GetRepoFromCache get repository list from cache, it refreshes the cache if it's empty.
func GetRepoFromCache() ([]string, error) {

	result := Cache.Get(catalogKey)
	if result == nil {
		err := RefreshCatalogCache()
		if err != nil {
			return nil, err
		}
		cached := Cache.Get(catalogKey)
		if cached != nil {
			return cached.([]string), nil
		}
		return nil, nil
	}
	return result.([]string), nil
}