// Copyright (c) 2016-present Mattermost, Inc. All Rights Reserved.
// See License.txt for license information.

package app

import (
	"net/http"
	"runtime/debug"
	"sync/atomic"

	l4g "github.com/alecthomas/log4go"
	"github.com/gorilla/mux"

	"github.com/mattermost/mattermost-server/einterfaces"
	ejobs "github.com/mattermost/mattermost-server/einterfaces/jobs"
	"github.com/mattermost/mattermost-server/jobs"
	"github.com/mattermost/mattermost-server/model"
	"github.com/mattermost/mattermost-server/plugin/pluginenv"
	"github.com/mattermost/mattermost-server/store"
	"github.com/mattermost/mattermost-server/store/sqlstore"
	"github.com/mattermost/mattermost-server/utils"
)

type App struct {
	goroutineCount      int32
	goroutineExitSignal chan struct{}

	Srv *Server

	PluginEnv              *pluginenv.Environment
	PluginConfigListenerId string

	EmailBatching *EmailBatchingJob

	Hubs                        []*Hub
	HubsStopCheckingForDeadlock chan bool

	Jobs *jobs.JobServer

	AccountMigration einterfaces.AccountMigrationInterface
	Brand            einterfaces.BrandInterface
	Cluster          einterfaces.ClusterInterface
	Compliance       einterfaces.ComplianceInterface
	DataRetention    einterfaces.DataRetentionInterface
	Elasticsearch    einterfaces.ElasticsearchInterface
	Emoji            einterfaces.EmojiInterface
	Ldap             einterfaces.LdapInterface
	Metrics          einterfaces.MetricsInterface
	Mfa              einterfaces.MfaInterface
	Saml             einterfaces.SamlInterface

	configFile string
	newStore   func() store.Store

	sessionCache *utils.Cache
}

var appCount = 0

// New creates a new App. You must call Shutdown when you're done with it.
// XXX: For now, only one at a time is allowed as some resources are still shared.
func New(options ...Option) *App {
	appCount++
	if appCount > 1 {
		panic("Only one App should exist at a time. Did you forget to call Shutdown()?")
	}

	app := &App{
		goroutineExitSignal: make(chan struct{}, 1),
		Srv: &Server{
			Router: mux.NewRouter(),
		},
		sessionCache: utils.NewLru(model.SESSION_CACHE_SIZE),
		configFile:   "config.json",
	}

	for _, option := range options {
		option(app)
	}

	if utils.T == nil {
		utils.TranslationsPreInit()
	}
	utils.LoadGlobalConfig(app.configFile)
	utils.InitTranslations(utils.Cfg.LocalizationSettings)

	l4g.Info(utils.T("api.server.new_server.init.info"))

	app.initEnterprise()

	if app.newStore == nil {
		app.newStore = func() store.Store {
			return store.NewLayeredStore(sqlstore.NewSqlSupplier(app.Config().SqlSettings, app.Metrics), app.Metrics, app.Cluster)
		}
	}

	app.Srv.Store = app.newStore()
	app.initJobs()

	app.initBuiltInPlugins()
	app.Srv.Router.HandleFunc("/plugins/{plugin_id:[A-Za-z0-9\\_\\-\\.]+}", app.ServePluginRequest)
	app.Srv.Router.HandleFunc("/plugins/{plugin_id:[A-Za-z0-9\\_\\-\\.]+}/{anything:.*}", app.ServePluginRequest)

	app.Srv.Router.NotFoundHandler = http.HandlerFunc(app.Handle404)

	app.Srv.WebSocketRouter = &WebSocketRouter{
		app:      app,
		handlers: make(map[string]webSocketHandler),
	}

	return app
}

func (a *App) Shutdown() {
	appCount--

	l4g.Info(utils.T("api.server.stop_server.stopping.info"))

	a.StopServer()
	a.HubStop()

	a.ShutDownPlugins()
	a.WaitForGoroutines()

	a.Srv.Store.Close()
	a.Srv = nil

	l4g.Info(utils.T("api.server.stop_server.stopped.info"))
}

var accountMigrationInterface func(*App) einterfaces.AccountMigrationInterface

func RegisterAccountMigrationInterface(f func(*App) einterfaces.AccountMigrationInterface) {
	accountMigrationInterface = f
}

var brandInterface func(*App) einterfaces.BrandInterface

func RegisterBrandInterface(f func(*App) einterfaces.BrandInterface) {
	brandInterface = f
}

var clusterInterface func(*App) einterfaces.ClusterInterface

func RegisterClusterInterface(f func(*App) einterfaces.ClusterInterface) {
	clusterInterface = f
}

var complianceInterface func(*App) einterfaces.ComplianceInterface

func RegisterComplianceInterface(f func(*App) einterfaces.ComplianceInterface) {
	complianceInterface = f
}

var dataRetentionInterface func(*App) einterfaces.DataRetentionInterface

func RegisterDataRetentionInterface(f func(*App) einterfaces.DataRetentionInterface) {
	dataRetentionInterface = f
}

var elasticsearchInterface func(*App) einterfaces.ElasticsearchInterface

func RegisterElasticsearchInterface(f func(*App) einterfaces.ElasticsearchInterface) {
	elasticsearchInterface = f
}

var emojiInterface func(*App) einterfaces.EmojiInterface

func RegisterEmojiInterface(f func(*App) einterfaces.EmojiInterface) {
	emojiInterface = f
}

var jobsDataRetentionJobInterface func(*App) ejobs.DataRetentionJobInterface

func RegisterJobsDataRetentionJobInterface(f func(*App) ejobs.DataRetentionJobInterface) {
	jobsDataRetentionJobInterface = f
}

var jobsElasticsearchAggregatorInterface func(*App) ejobs.ElasticsearchAggregatorInterface

func RegisterJobsElasticsearchAggregatorInterface(f func(*App) ejobs.ElasticsearchAggregatorInterface) {
	jobsElasticsearchAggregatorInterface = f
}

var jobsElasticsearchIndexerInterface func(*App) ejobs.ElasticsearchIndexerInterface

func RegisterJobsElasticsearchIndexerInterface(f func(*App) ejobs.ElasticsearchIndexerInterface) {
	jobsElasticsearchIndexerInterface = f
}

var jobsLdapSyncInterface func(*App) ejobs.LdapSyncInterface

func RegisterJobsLdapSyncInterface(f func(*App) ejobs.LdapSyncInterface) {
	jobsLdapSyncInterface = f
}

var ldapInterface func(*App) einterfaces.LdapInterface

func RegisterLdapInterface(f func(*App) einterfaces.LdapInterface) {
	ldapInterface = f
}

var metricsInterface func(*App) einterfaces.MetricsInterface

func RegisterMetricsInterface(f func(*App) einterfaces.MetricsInterface) {
	metricsInterface = f
}

var mfaInterface func(*App) einterfaces.MfaInterface

func RegisterMfaInterface(f func(*App) einterfaces.MfaInterface) {
	mfaInterface = f
}

var samlInterface func(*App) einterfaces.SamlInterface

func RegisterSamlInterface(f func(*App) einterfaces.SamlInterface) {
	samlInterface = f
}

func (a *App) initEnterprise() {
	if accountMigrationInterface != nil {
		a.AccountMigration = accountMigrationInterface(a)
	}
	if brandInterface != nil {
		a.Brand = brandInterface(a)
	}
	if clusterInterface != nil {
		a.Cluster = clusterInterface(a)
	}
	if complianceInterface != nil {
		a.Compliance = complianceInterface(a)
	}
	if elasticsearchInterface != nil {
		a.Elasticsearch = elasticsearchInterface(a)
	}
	if emojiInterface != nil {
		a.Emoji = emojiInterface(a)
	}
	if ldapInterface != nil {
		a.Ldap = ldapInterface(a)
		utils.AddConfigListener(func(_, cfg *model.Config) {
			if err := utils.ValidateLdapFilter(cfg, a.Ldap); err != nil {
				panic(utils.T(err.Id))
			}
		})
	}
	if metricsInterface != nil {
		a.Metrics = metricsInterface(a)
	}
	if mfaInterface != nil {
		a.Mfa = mfaInterface(a)
	}
	if samlInterface != nil {
		a.Saml = samlInterface(a)
		utils.AddConfigListener(func(_, cfg *model.Config) {
			a.Saml.ConfigureSP()
		})
	}
	if dataRetentionInterface != nil {
		a.DataRetention = dataRetentionInterface(a)
	}
}

func (a *App) initJobs() {
	a.Jobs = jobs.NewJobServer(a.Config, a.Srv.Store)
	if jobsDataRetentionJobInterface != nil {
		a.Jobs.DataRetentionJob = jobsDataRetentionJobInterface(a)
	}
	if jobsElasticsearchAggregatorInterface != nil {
		a.Jobs.ElasticsearchAggregator = jobsElasticsearchAggregatorInterface(a)
	}
	if jobsElasticsearchIndexerInterface != nil {
		a.Jobs.ElasticsearchIndexer = jobsElasticsearchIndexerInterface(a)
	}
	if jobsLdapSyncInterface != nil {
		a.Jobs.LdapSync = jobsLdapSyncInterface(a)
	}
}

func (a *App) Config() *model.Config {
	return utils.Cfg
}

func (a *App) UpdateConfig(f func(*model.Config)) {
	old := utils.Cfg.Clone()
	f(utils.Cfg)
	utils.InvokeGlobalConfigListeners(old, utils.Cfg)
}

func (a *App) PersistConfig() {
	utils.SaveConfig(a.ConfigFileName(), a.Config())
}

func (a *App) ReloadConfig() {
	debug.FreeOSMemory()
	utils.LoadGlobalConfig(a.ConfigFileName())

	// start/restart email batching job if necessary
	a.InitEmailBatching()
}

func (a *App) ConfigFileName() string {
	return utils.CfgFileName
}

// Go creates a goroutine, but maintains a record of it to ensure that execution completes before
// the app is destroyed.
func (a *App) Go(f func()) {
	atomic.AddInt32(&a.goroutineCount, 1)

	go func() {
		f()

		atomic.AddInt32(&a.goroutineCount, -1)
		select {
		case a.goroutineExitSignal <- struct{}{}:
		default:
		}
	}()
}

// WaitForGoroutines blocks until all goroutines created by App.Go exit.
func (a *App) WaitForGoroutines() {
	for atomic.LoadInt32(&a.goroutineCount) != 0 {
		<-a.goroutineExitSignal
	}
}

func (a *App) Handle404(w http.ResponseWriter, r *http.Request) {
	err := model.NewAppError("Handle404", "api.context.404.app_error", nil, "", http.StatusNotFound)
	err.Translate(utils.T)

	l4g.Debug("%v: code=404 ip=%v", r.URL.Path, utils.GetIpAddress(r))

	utils.RenderWebError(err, w, r)
}