package main

import (
	"bufio"
	"context"
	"encoding/json"
	"fmt"
	"gitea.pena/PenaSide/customer/cmd/sse_bench/worker"
	"github.com/gofiber/fiber/v2"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
	"go.uber.org/zap"
	"log"
	"time"
)

func initDB(ctx context.Context) (*mongo.Client, *mongo.Collection) {
	clientOptions := options.Client().ApplyURI("mongodb://localhost:27017,localhost:27018,localhost:27019/?replicaSet=rs0&readPreference=primary&ssl=false")
	client, err := mongo.Connect(context.Background(), clientOptions)
	if err != nil {
		panic(err)
	}

	collection := client.Database("testdb").Collection("testcollection")
	collection.Drop(ctx)
	for i := 0; i < 1000; i++ {
		_, err := collection.InsertOne(ctx, bson.M{"userId": fmt.Sprintf("user%d", i), "field": "value"})
		if err != nil {
			panic(err)
		}
	}

	return client, collection
}

func initSrv(repo *AccountRepository, logger *zap.Logger, watchWorker *worker.WatchWorker) *fiber.App {
	app := fiber.New()
	controller := &AccountController{
		accountRepo: repo,
		logger:      logger,
		watchWorker: watchWorker,
	}
	app.Get("/account-pipe/:userID", controller.AccountPipe)
	app.Use("/account-pipe-wc/:userID", controller.AccountPipeWC)
	return app
}

type AccountController struct {
	accountRepo *AccountRepository
	logger      *zap.Logger
	watchWorker *worker.WatchWorker
}

func (receiver *AccountController) AccountPipe(ctx *fiber.Ctx) error {
	userID := ctx.Params("userID")

	ctx.Set(fiber.HeaderContentType, "text/event-stream")
	ctx.Set("Cache-Control", "no-cache")
	ctx.Set("Connection", "keep-alive")
	ctx.Set("Transfer-Encoding", "chunked")

	accountCh := make(chan map[string]interface{})
	cancelCtx, cancel := context.WithCancel(ctx.Context())

	go func(ctx context.Context) {
		defer close(accountCh)
		if err := receiver.accountRepo.AccountPipe(ctx, userID, accountCh); err != nil {
			//receiver.logger.Error("error in account pipe repo method", zap.Error(err))
		}
	}(cancelCtx)

	ctx.Status(fiber.StatusOK).Context().SetBodyStreamWriter(func(w *bufio.Writer) {
		pingTicker := time.NewTicker(5 * time.Second)
		defer pingTicker.Stop()
		for {
			select {
			case accountData, ok := <-accountCh:
				if !ok {
					return
				}
				accountJSON, err := json.Marshal(accountData)
				if err != nil {
					//receiver.logger.Error("error marshal account JSON", zap.Error(err))
					continue
				}
				fmt.Println(accountJSON)
				fmt.Fprintf(w, "data: %s\n\n", accountJSON)
				if err := w.Flush(); err != nil {
					//receiver.logger.Error("error flushing", zap.Error(err))
					cancel()
					//receiver.logger.Info("Close connection Account Pipe sse")
					return
				}
			case <-pingTicker.C:
				fmt.Fprintf(w, "data: %s\n\n", `{"event": "ping"}`)
				if err := w.Flush(); err != nil {
					//receiver.logger.Error("error sending ping Account Pipe sse, close connection", zap.Error(err))
					cancel()
					return
				}
			}
		}
	})

	return nil
}

func (receiver *AccountController) AccountPipeWC(ctx *fiber.Ctx) error {
	userID := ctx.Params("userID")

	ctx.Set(fiber.HeaderContentType, "text/event-stream")
	ctx.Set("Cache-Control", "no-cache")
	ctx.Set("Connection", "keep-alive")
	ctx.Set("Transfer-Encoding", "chunked")

	accountCh := make(chan map[string]interface{})
	//cancelCtx, cancel := context.WithCancel(ctx.Context())

	receiver.watchWorker.AddChannel(userID, accountCh)

	ctx.Status(fiber.StatusOK).Context().SetBodyStreamWriter(func(w *bufio.Writer) {
		pingTicker := time.NewTicker(5 * time.Second)
		defer pingTicker.Stop()
		for {
			select {
			case accountData, ok := <-accountCh:
				if !ok {
					return
				}
				accountJSON, err := json.Marshal(accountData)
				if err != nil {
					receiver.logger.Error("error marshal account JSON", zap.Error(err))
					continue
				}
				fmt.Fprintf(w, "data: %s\n\n", accountJSON)
				if err := w.Flush(); err != nil {
					//receiver.logger.Error("error flushing", zap.Error(err))
					//cancel()
					//receiver.logger.Info("Close connection Account Pipe sse")
					//receiver.watchWorker.DropChannel(userID)
					return
				}
			case <-pingTicker.C:
				fmt.Fprintf(w, "data: %s\n\n", `{"event": "ping"}`)
				if err := w.Flush(); err != nil {
					//receiver.logger.Error("error sending ping Account Pipe sse, close connection", zap.Error(err))
					//receiver.watchWorker.DropChannel(userID)
					//cancel()
					return
				}
			}
		}
	})

	return nil
}

type AccountRepository struct {
	mongoDB *mongo.Collection
	logger  *zap.Logger
}

func (receiver *AccountRepository) AccountPipe(ctx context.Context, userID string, accountCh chan<- map[string]interface{}) error {
	pipeline := mongo.Pipeline{
		{{"$match", bson.M{"operationType": "update", "fullDocument.userId": userID}}},
	}

	opts := options.ChangeStream()
	opts.SetFullDocument(options.UpdateLookup)
	changeStream, err := receiver.mongoDB.Watch(ctx, pipeline, opts)
	if err != nil {
		return err
	}
	defer changeStream.Close(ctx)

	for {
		select {
		case <-ctx.Done():
			//receiver.logger.Info("Context canceled, thread is closed now")
			return nil
		default:
			if changeStream.Next(ctx) {
				var changeEvent struct {
					UpdateDescription struct {
						UpdatedFields map[string]interface{} `bson:"updatedFields"`
					} `bson:"updateDescription"`
				}
				if err := changeStream.Decode(&changeEvent); err != nil {
					//receiver.logger.Error("error decoding change event", zap.Error(err))
					continue
				}
				select {
				case accountCh <- changeEvent.UpdateDescription.UpdatedFields:
				case <-ctx.Done():
					return nil
				}
			}
		}
	}
}

func main() {
	ctx := context.Background()

	logger, err := zap.NewProduction()
	if err != nil {
		log.Fatalf(err.Error())
	}
	defer logger.Sync()

	client, collection := initDB(ctx)
	defer func() {
		if err := client.Disconnect(ctx); err != nil {
			logger.Fatal("Error close mongo", zap.Error(err))
		}
	}()

	repo := &AccountRepository{
		mongoDB: collection,
		logger:  logger,
	}

	watchWorker := worker.NewWatchWorker(collection, logger)
	go watchWorker.Run(ctx)

	go func() {
		for {
			select {
			case <-ctx.Done():
				fmt.Println("stop update")
				return
			default:
				for i := 0; i < 800; i++ {
					fmt.Println("YA WORK OKAY")
					res, err := collection.UpdateOne(ctx, bson.M{"userId": fmt.Sprintf("user%d", i)},
						bson.M{"$set": bson.M{"field": fmt.Sprintf("value-%d", time.Now().UnixNano())}})
					if err != nil {
						logger.Error("error update", zap.Error(err))
					}
					fmt.Println("TOCHNO OKAY", res.ModifiedCount)
				}
				time.Sleep(1 * time.Second)
			}
		}
	}()

	app := initSrv(repo, logger, watchWorker)

	if err := app.Listen(":3000"); err != nil {
		logger.Fatal("Error server", zap.Error(err))
	}
}