game Of Life

src/boxes/boxes.go

@@ -0,0 +1,152 @@
+package boxes
+
+import (
+	"fmt"
+	"math/rand"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/labstack/echo/v4"
+	"github.com/labstack/gommon/log"
+	"golang.org/x/net/websocket"
+)
+
+var (
+	wsConnections = make(map[*websocket.Conn]bool)
+	wsMutex       sync.Mutex
+	db            = initDb()
+	random        = rand.New(rand.NewSource(time.Now().UnixNano()))
+)
+
+type Box struct {
+	Id    int
+	Value bool
+}
+
+func deserializeBox(msg string) (Box, error) {
+	parts := strings.Split(msg, ":")
+	index, err := strconv.Atoi(parts[1])
+	if err != nil {
+		return Box{}, err
+	}
+	checked := parts[2] == "+"
+	return Box{index, checked}, nil
+}
+
+func (box Box) serialize() string {
+	message := "b:" + strconv.Itoa(box.Id)
+	if box.Value {
+		message += ":+"
+	} else {
+		message += ":-"
+	}
+	return message + "\n"
+}
+
+func handleWsError(err error, conn *websocket.Conn) {
+	if err != nil {
+		log.Errorf("Failed to handle websocket: %v", err)
+		conn.Close()
+		wsMutex.Lock()
+		defer wsMutex.Unlock()
+		delete(wsConnections, conn)
+	}
+}
+
+func broadcastMessage(message string) {
+	wsMutex.Lock()
+	defer wsMutex.Unlock()
+
+	for conn := range wsConnections {
+		err := websocket.Message.Send(conn, message)
+		handleWsError(err, conn)
+
+	}
+}
+
+func handleMessage(msg string, ws *websocket.Conn) error {
+	if msg == "gol" {
+		matrix := make(map[string]Box)
+		boxes := GetBoxes()
+		index := 0
+		for i := 0; i < 32; i++ {
+			for j := 0; j < 32; j++ {
+				matrix[fmt.Sprintf("%d-%d", i, j)] = boxes[index]
+				index++
+			}
+		}
+		log.Error(matrix)
+		nextGen := make([]Box, 0)
+		for id, item := range matrix {
+			nextItem := shouldBeAlive(matrix, id)
+			if nextItem.Value != item.Value {
+				nextGen = append(nextGen, shouldBeAlive(matrix, id))
+			}
+
+		}
+
+		nextMessage := ""
+		for _, item := range nextGen {
+			item.persist()
+			nextMessage += item.serialize()
+		}
+		broadcastMessage(nextMessage)
+
+	} else if msg == "random" {
+		index := random.Int() % 1000
+		box, err := getBox(index)
+		if err != nil {
+			log.Fatal(err)
+		}
+		box.Value = !box.Value
+		box.persist()
+
+		message := box.serialize()
+		broadcastMessage(message)
+
+	} else if strings.Contains(msg, "b:") {
+		box, err := deserializeBox(msg)
+		if err != nil {
+			return err
+		}
+
+		broadcastMessage(msg)
+		box.persist()
+	} else if strings.Contains(msg, "ping") {
+		len := len(wsConnections)
+		websocket.Message.Send(ws, "pong-"+strconv.Itoa(len))
+	}
+	return nil
+}
+
+func InitWs(c echo.Context) error {
+	websocket.Handler(func(ws *websocket.Conn) {
+		wsMutex.Lock()
+		wsConnections[ws] = true
+		wsMutex.Unlock()
+
+		boxes := GetBoxes()
+		msg := ""
+		for _, box := range boxes {
+			msg += box.serialize()
+		}
+
+		err := websocket.Message.Send(ws, msg)
+		handleWsError(err, ws)
+
+		for {
+			var msg string
+			err := websocket.Message.Receive(ws, &msg)
+			handleWsError(err, ws)
+			if err != nil {
+				break
+			}
+			handleMessage(msg, ws)
+			log.Infof("Received message: %s", msg)
+		}
+	}).ServeHTTP(c.Response(), c.Request())
+
+	return nil
+}