package main

import (
	"bufio"
	"fmt"
	"os"
	"time"

	"clickandjoin.app/serversenteventsserver/modules/cache"
	"clickandjoin.app/serversenteventsserver/modules/config"
	"clickandjoin.app/serversenteventsserver/modules/rabbitmq"
	"clickandjoin.app/serversenteventsserver/modules/structs"
	"github.com/gofiber/fiber/v2"
	"github.com/gofiber/fiber/v2/middleware/cors"
	"github.com/google/uuid"
	"github.com/sirupsen/logrus"
	"github.com/valyala/fasthttp"
)

func init() {
	config.LoadConfig()

	if config.Cfg.Debug {
		logrus.SetLevel(logrus.DebugLevel)
	}

	logrus.Println("Debug:", config.Cfg.Debug)

	go rabbitmq.Init()
}

func main() {
	app := fiber.New()

	// wait so that rabbitmq can connect
	// TODO: better way to handle this
	time.Sleep(500 * time.Millisecond)

	if len(os.Args) < 2 {
		logrus.Fatalln("Please specify port")
	}

	// TODO: origin
	// CORS for external resources
	app.Use(cors.New(cors.Config{
		AllowOrigins:     "*",
		AllowHeaders:     "Cache-Control",
		AllowCredentials: true,
	}))

	app.Get("/sse", func(c *fiber.Ctx) error {
		c.Set("Content-Type", "text/event-stream")
		c.Set("Cache-Control", "no-cache")
		c.Set("Connection", "keep-alive")
		c.Set("Transfer-Encoding", "chunked")

		c.Context().SetBodyStreamWriter(fasthttp.StreamWriter(func(w *bufio.Writer) {
			var sseclient structs.SSEClient

			sseclient.MessageChan = make(chan structs.SSEClientChanMessage)

			clientId := uuid.New()

			cache.SSEClients[clientId] = sseclient

			logrus.Debugln("NEW CLIENT ID:", clientId)
			logrus.Debugln(len(cache.SSEClients), "CLIENTS CONNECTED")

			for message := range sseclient.MessageChan {
				fmt.Fprintf(w, "data: %s\n\n", message.Message)

				err := w.Flush()

				if err != nil {
					// Refreshing page in web browser will establish a new
					// SSE connection, but only (the last) one is alive, so
					// dead connections must be closed here.

					for id, sseClient := range cache.SSEClients {
						if id == message.ClientId {
							close(sseClient.MessageChan)
							delete(cache.SSEClients, id)
							logrus.Debugln("DELETE clientId:", id)
						}
					}
				}
			}
		}))

		return nil
	})

	app.Listen("127.0.0.1:" + os.Args[1])
}