From 38ac32e46009a82f3d23861ad586faf3131233dc Mon Sep 17 00:00:00 2001
From: Marco <mgross@sw-gross.de>
Date: Sat, 19 Nov 2022 13:25:00 +0100
Subject: [PATCH] Add move logic and helpers.

---
 go.mod               |  4 ++--
 main.go              |  2 +-
 server/chess.go      | 49 ++++++++++++++++++++++++++++++++++++++++
 server/chess_move.go | 54 ++++++++++++++++++++++++++++++++++++++++++++
 server/server.go     | 18 ++++-----------
 5 files changed, 110 insertions(+), 17 deletions(-)
 create mode 100644 server/chess.go
 create mode 100644 server/chess_move.go

diff --git a/go.mod b/go.mod
index 4cfea72..446a51e 100644
--- a/go.mod
+++ b/go.mod
@@ -1,5 +1,5 @@
-module ws_server
+module mchess_server
 
 go 1.19
 
-require github.com/gorilla/websocket v1.5.0 // indirect
+require github.com/gorilla/websocket v1.5.0
diff --git a/main.go b/main.go
index 0fa7ce3..78473da 100644
--- a/main.go
+++ b/main.go
@@ -2,8 +2,8 @@ package main
 
 import (
 	"log"
+	"mchess_server/server"
 	"net/http"
-	"ws_server/server"
 )
 
 func main() {
diff --git a/server/chess.go b/server/chess.go
new file mode 100644
index 0000000..17eeedc
--- /dev/null
+++ b/server/chess.go
@@ -0,0 +1,49 @@
+package server
+
+import (
+	"log"
+	"math/rand"
+
+	"github.com/gorilla/websocket"
+)
+
+type chessGame struct {
+	id int
+}
+
+func NewChessGame() *chessGame {
+	var game chessGame = chessGame{
+		id: rand.Int(),
+	}
+
+	return &game
+}
+
+func (game *chessGame) handle(conn *websocket.Conn) {
+	for {
+		messageType, receivedMessage, err := conn.ReadMessage()
+		if err != nil {
+			log.Println("Error during message reading:", err)
+			break
+		}
+
+		move, err := parseMove(string(receivedMessage))
+		if err != nil {
+			log.Println("Game: ", game.id, err)
+			return
+		}
+
+		log.Println("Game ", game.id, " move: ", move)
+
+		messageToBeSent := moveToString(*move)
+		log.Println("About to send: ", messageToBeSent)
+
+		err = conn.WriteMessage(messageType, []byte(messageToBeSent))
+		if err != nil {
+			log.Println("Error during message writing:", err)
+			break
+		}
+
+	}
+
+}
diff --git a/server/chess_move.go b/server/chess_move.go
new file mode 100644
index 0000000..56b2f88
--- /dev/null
+++ b/server/chess_move.go
@@ -0,0 +1,54 @@
+package server
+
+import (
+	"errors"
+	"fmt"
+	"log"
+	"strings"
+)
+
+type chessMove struct {
+	realMove    bool
+	startSquare chessCoordinate
+	endSquare   chessCoordinate
+}
+
+type chessCoordinate struct {
+	col int
+	row int
+}
+
+func parseMove(received string) (*chessMove, error) {
+	var move chessMove
+
+	splitReceived := strings.Split(received, " ")
+	log.Println(splitReceived)
+
+	realMoveString := splitReceived[1]
+	startSquareString := splitReceived[2]
+	endSquareString := splitReceived[3]
+
+	if strings.Compare(realMoveString, "mv") == 0 {
+		move.realMove = true
+	} else if strings.Compare(realMoveString, "pc") == 0 {
+		move.realMove = false
+	} else {
+		return nil, errors.New("NEITHER MV OR PC RECEIVED AS FIRST BYTES")
+	}
+
+	move.startSquare.col = int(([]rune(startSquareString)[0] - '0'))
+	move.startSquare.row = int(([]rune(startSquareString)[1] - '0'))
+
+	move.endSquare.col = int(([]rune(endSquareString)[0] - '0'))
+	move.endSquare.row = int(([]rune(endSquareString)[1] - '0'))
+
+	return &move, nil
+}
+
+func moveToString(move chessMove) string {
+
+	str := fmt.Sprint(move.startSquare.col) + fmt.Sprint(move.startSquare.row) +
+		" " + fmt.Sprint(move.endSquare.col) + fmt.Sprint(move.endSquare.row)
+
+	return str
+}
diff --git a/server/server.go b/server/server.go
index 2c22695..fae0b42 100644
--- a/server/server.go
+++ b/server/server.go
@@ -10,6 +10,8 @@ import (
 var upgrader = websocket.Upgrader{} // use default options
 
 func SocketHandler(w http.ResponseWriter, r *http.Request) {
+	log.Println("SocketHandler invoked")
+
 	conn, err := upgrader.Upgrade(w, r, nil)
 	if err != nil {
 		log.Print("Error during connection upgrading:", err)
@@ -17,18 +19,6 @@ func SocketHandler(w http.ResponseWriter, r *http.Request) {
 	}
 	defer conn.Close()
 
-	// The event loop
-	for {
-		messageType, message, err := conn.ReadMessage()
-		if err != nil {
-			log.Println("Error during message reading:", err)
-			break
-		}
-		log.Printf("Received: %s", message)
-		err = conn.WriteMessage(messageType, message)
-		if err != nil {
-			log.Println("Error during message writing:", err)
-			break
-		}
-	}
+	var game = NewChessGame()
+	game.handle(conn)
 }