// Copyright (c) 2017-present Mattermost, Inc. All Rights Reserved.
// See License.txt for license information.

package jobs

import (
	"sync"

	"github.com/mattermost/mattermost-server/mlog"
	"github.com/mattermost/mattermost-server/model"
	"github.com/mattermost/mattermost-server/services/configservice"
)

type Workers struct {
	startOnce     sync.Once
	ConfigService configservice.ConfigService
	Watcher       *Watcher

	DataRetention            model.Worker
	MessageExport            model.Worker
	ElasticsearchIndexing    model.Worker
	ElasticsearchAggregation model.Worker
	LdapSync                 model.Worker
	Migrations               model.Worker
	Plugins                  model.Worker

	listenerId string
}

func (srv *JobServer) InitWorkers() *Workers {
	workers := &Workers{
		ConfigService: srv.ConfigService,
	}
	workers.Watcher = srv.MakeWatcher(workers, DEFAULT_WATCHER_POLLING_INTERVAL)

	if srv.DataRetentionJob != nil {
		workers.DataRetention = srv.DataRetentionJob.MakeWorker()
	}

	if srv.MessageExportJob != nil {
		workers.MessageExport = srv.MessageExportJob.MakeWorker()
	}

	if elasticsearchIndexerInterface := srv.ElasticsearchIndexer; elasticsearchIndexerInterface != nil {
		workers.ElasticsearchIndexing = elasticsearchIndexerInterface.MakeWorker()
	}

	if elasticsearchAggregatorInterface := srv.ElasticsearchAggregator; elasticsearchAggregatorInterface != nil {
		workers.ElasticsearchAggregation = elasticsearchAggregatorInterface.MakeWorker()
	}

	if ldapSyncInterface := srv.LdapSync; ldapSyncInterface != nil {
		workers.LdapSync = ldapSyncInterface.MakeWorker()
	}

	if migrationsInterface := srv.Migrations; migrationsInterface != nil {
		workers.Migrations = migrationsInterface.MakeWorker()
	}

	if pluginsInterface := srv.Plugins; pluginsInterface != nil {
		workers.Migrations = pluginsInterface.MakeWorker()
	}

	return workers
}

func (workers *Workers) Start() *Workers {
	mlog.Info("Starting workers")

	workers.startOnce.Do(func() {
		if workers.DataRetention != nil && (*workers.ConfigService.Config().DataRetentionSettings.EnableMessageDeletion || *workers.ConfigService.Config().DataRetentionSettings.EnableFileDeletion) {
			go workers.DataRetention.Run()
		}

		if workers.MessageExport != nil && *workers.ConfigService.Config().MessageExportSettings.EnableExport {
			go workers.MessageExport.Run()
		}

		if workers.ElasticsearchIndexing != nil && *workers.ConfigService.Config().ElasticsearchSettings.EnableIndexing {
			go workers.ElasticsearchIndexing.Run()
		}

		if workers.ElasticsearchAggregation != nil && *workers.ConfigService.Config().ElasticsearchSettings.EnableIndexing {
			go workers.ElasticsearchAggregation.Run()
		}

		if workers.LdapSync != nil && *workers.ConfigService.Config().LdapSettings.EnableSync {
			go workers.LdapSync.Run()
		}

		if workers.Migrations != nil {
			go workers.Migrations.Run()
		}

		go workers.Watcher.Start()
	})

	workers.listenerId = workers.ConfigService.AddConfigListener(workers.handleConfigChange)

	return workers
}

func (workers *Workers) handleConfigChange(oldConfig *model.Config, newConfig *model.Config) {
	mlog.Debug("Workers received config change.")

	if workers.DataRetention != nil {
		if (!*oldConfig.DataRetentionSettings.EnableMessageDeletion && !*oldConfig.DataRetentionSettings.EnableFileDeletion) && (*newConfig.DataRetentionSettings.EnableMessageDeletion || *newConfig.DataRetentionSettings.EnableFileDeletion) {
			go workers.DataRetention.Run()
		} else if (*oldConfig.DataRetentionSettings.EnableMessageDeletion || *oldConfig.DataRetentionSettings.EnableFileDeletion) && (!*newConfig.DataRetentionSettings.EnableMessageDeletion && !*newConfig.DataRetentionSettings.EnableFileDeletion) {
			workers.DataRetention.Stop()
		}
	}

	if workers.MessageExport != nil {
		if !*oldConfig.MessageExportSettings.EnableExport && *newConfig.MessageExportSettings.EnableExport {
			go workers.MessageExport.Run()
		} else if *oldConfig.MessageExportSettings.EnableExport && !*newConfig.MessageExportSettings.EnableExport {
			workers.MessageExport.Stop()
		}
	}

	if workers.ElasticsearchIndexing != nil {
		if !*oldConfig.ElasticsearchSettings.EnableIndexing && *newConfig.ElasticsearchSettings.EnableIndexing {
			go workers.ElasticsearchIndexing.Run()
		} else if *oldConfig.ElasticsearchSettings.EnableIndexing && !*newConfig.ElasticsearchSettings.EnableIndexing {
			workers.ElasticsearchIndexing.Stop()
		}
	}

	if workers.ElasticsearchAggregation != nil {
		if !*oldConfig.ElasticsearchSettings.EnableIndexing && *newConfig.ElasticsearchSettings.EnableIndexing {
			go workers.ElasticsearchAggregation.Run()
		} else if *oldConfig.ElasticsearchSettings.EnableIndexing && !*newConfig.ElasticsearchSettings.EnableIndexing {
			workers.ElasticsearchAggregation.Stop()
		}
	}

	if workers.LdapSync != nil {
		if !*oldConfig.LdapSettings.EnableSync && *newConfig.LdapSettings.EnableSync {
			go workers.LdapSync.Run()
		} else if *oldConfig.LdapSettings.EnableSync && !*newConfig.LdapSettings.EnableSync {
			workers.LdapSync.Stop()
		}
	}
}

func (workers *Workers) Stop() *Workers {
	workers.ConfigService.RemoveConfigListener(workers.listenerId)

	workers.Watcher.Stop()

	if workers.DataRetention != nil && (*workers.ConfigService.Config().DataRetentionSettings.EnableMessageDeletion || *workers.ConfigService.Config().DataRetentionSettings.EnableFileDeletion) {
		workers.DataRetention.Stop()
	}

	if workers.MessageExport != nil && *workers.ConfigService.Config().MessageExportSettings.EnableExport {
		workers.MessageExport.Stop()
	}

	if workers.ElasticsearchIndexing != nil && *workers.ConfigService.Config().ElasticsearchSettings.EnableIndexing {
		workers.ElasticsearchIndexing.Stop()
	}

	if workers.ElasticsearchAggregation != nil && *workers.ConfigService.Config().ElasticsearchSettings.EnableIndexing {
		workers.ElasticsearchAggregation.Stop()
	}

	if workers.LdapSync != nil && *workers.ConfigService.Config().LdapSettings.EnableSync {
		workers.LdapSync.Stop()
	}

	if workers.Migrations != nil {
		workers.Migrations.Stop()
	}

	mlog.Info("Stopped workers")

	return workers
}