package app

import (
	"context"
	log "github.com/sirupsen/logrus"
	"google.golang.org/grpc"
	"net"
	"runtime"
	"task-processor/config"
	"task-processor/internal/appState"
	"task-processor/internal/parsers"
	"task-processor/internal/parsers/mandarake"
	"task-processor/internal/processor"
	"task-processor/internal/remote"
	"task-processor/internal/shared"
	"task-processor/pkg/router"
	"time"
)

type App struct {
	config       *config.Config
	checkPeriod  time.Duration
	startTime    time.Time
	retryCount   int
	retryMinutes int
	state        *appState.State
	network      *remote.Network
	numCPUs      int
	metricsSrv   *router.Handler
	taskApiSrv   *grpc.Server
}

func New(c *config.Config) *App {
	numCPUs := c.NumCPUs
	if numCPUs < 1 {
		numCPUs = runtime.NumCPU()
	}

	st := appState.NewState(numCPUs, c.CheckPeriod, c.TasksCfg.RetryCount, c.TasksCfg.RetryMinutes)

	server := newServer(st)

	//metrics
	mSrv := router.NewHandler(router.Deps{
		Addr:    net.JoinHostPort(c.Metrics.Host, c.Metrics.Port),
		GinMode: c.Metrics.GinMode,
	})

	return &App{
		config:       c,
		checkPeriod:  time.Duration(c.CheckPeriod),
		startTime:    time.Now(),
		retryCount:   c.TasksCfg.RetryCount,
		retryMinutes: c.TasksCfg.RetryMinutes,
		state:        st,
		network:      remote.NewHandler(),
		numCPUs:      numCPUs,
		metricsSrv:   mSrv,
		taskApiSrv:   server,
	}
}

func (app *App) Run(ctx context.Context) {
	log.Info("Application start")

	addr := net.JoinHostPort(app.config.GrpcCfg.ServerHost, app.config.GrpcCfg.ServerPort)

	log.WithFields(log.Fields{
		"Service address": addr,
		"Number of CPUs":  app.numCPUs,
	}).Debug("App settings")

	errChan := make(chan error, 16)

	//main
	apiClient := newApiClient(app.config.GrpcCfg.ApiClientHost + ":" + app.config.GrpcCfg.ApiClientPort)

	sender := make(chan shared.TaskResult, app.numCPUs*10)
	defer close(sender)

	// external scrapper
	surugayaScrapper := newSurugayaScrapperClient(app.config.GrpcCfg.SurugayaScrapperHost + ":" + app.config.GrpcCfg.SurugayaScrapperPort)

	//task processor
	handlers := make(map[string]parsers.TaskHandler)

	if app.config.OriginEnabled.Surugaya {
		handlers[shared.OriginSurugaya] = parsers.NewSurugayaParser(surugayaScrapper)
	}

	if app.config.OriginEnabled.Mandarake {
		handlers[shared.OriginMandarake] = mandarake.NewParser(mandarake.Deps{
			Enabled:          app.config.OriginEnabled.Mandarake,
			ExternalBrowser:  app.config.ExternalBrowser,
			GoroutinesNumber: app.numCPUs,
			TaskTimeout:      app.config.TasksCfg.TaskTimeout,
		})
	}

	taskProcessor := processor.New(processor.Deps{
		Handlers: handlers,
		Out:      sender,
		State:    app.state,
		Ctx:      ctx,
		NumCPUs:  app.numCPUs,
	})

	process := func() {
		app.state.SetStatus(appState.StatusRequestTasks)
		log.Info("Requesting data for parsing")

		receivedTasks := app.network.RequestTasks(ctx, apiClient)
		log.WithField("length", len(receivedTasks)).Debug("End receiving")

		taskProcessor.StartWork(ctx, receivedTasks)
	}

	period := time.NewTicker(app.checkPeriod * time.Hour)
	defer period.Stop()

	go func() {
		process() //immediate start
		for range period.C {
			process()
		}
	}()

	//done tasks sender
	go func() {
		ticker := time.NewTicker(time.Second * 2)
		defer ticker.Stop()

		var sendData []shared.TaskResult

		for {
			select {
			case task := <-sender:
				sendData = append(sendData, task)

			case <-ticker.C:
				l := len(sendData)
				if l > 0 {
					log.WithField("length", l).Debug("Sending parsed data")
					app.network.SendResult(ctx, apiClient, sendData)
					sendData = sendData[:0]
				}
			}
		}
	}()

	//start metrics server
	go func() {
		if err := app.metricsSrv.Run(); err != nil {
			errChan <- err
		}
	}()

	//gRPC Server for status response
	go func() {
		listener, err := net.Listen("tcp", addr)
		if err != nil {
			errChan <- err
		}

		log.Infof("gRPC Server listening at %v", addr)
		if err = app.taskApiSrv.Serve(listener); err != nil {
			errChan <- err
		}
	}()

	select {
	case <-ctx.Done():
		app.shutdown(ctx)
	case err := <-errChan:
		log.WithError(err).Fatal("Application run error")
	}
}

func (app *App) shutdown(ctx context.Context) {
	log.Info("Shutting down...")

	app.taskApiSrv.GracefulStop()

	if err := app.metricsSrv.Shutdown(ctx); err != nil {
		log.WithError(err).Error("Failed to shutdown server")
	}
}