switch backend to clojure

backend/Dockerfile

@@ -1,44 +0,0 @@
-# Build stage
-FROM golang:1.25-bookworm AS builder
-
-WORKDIR /app
-
-# Install dependencies including libenet-dev from Debian repos
-RUN apt-get update && apt-get install -y --no-install-recommends \
-    git \
-    gcc \
-    pkg-config \
-    libenet-dev \
-    sqlite3 \
-    libsqlite3-dev \
-    && rm -rf /var/lib/apt/lists/*
-
-# Copy go mod and sum files
-COPY go.mod go.sum ./
-
-# Download dependencies
-RUN go mod download
-
-COPY ./*.go .
-
-# Enable CGO for go-sqlite3 and go-enet
-ENV CGO_ENABLED=1
-
-RUN go build -o main .
-
-# Runtime stage
-FROM debian:bookworm-slim
-
-WORKDIR /app
-
-# Install runtime dependencies
-RUN apt-get update && apt-get install -y --no-install-recommends \
-    libenet7 \
-    ca-certificates \
-    && rm -rf /var/lib/apt/lists/*
-
-COPY --from=builder /app/main .
-
-EXPOSE 8095
-
-CMD ["./main"]

backend/deps.edn

@@ -0,0 +1,23 @@
+{:paths ["src"]
+ :deps {        ;; db
+        com.datomic/local    {:mvn/version "1.0.291"}
+
+        ;; logging
+        com.taoensso/telemere {:mvn/version "1.0.0"}
+
+        ;; environment variables
+        environ/environ {:mvn/version "1.2.0"}
+
+        ;; json / schema validation
+        metosin/malli {:mvn/version "0.18.0"}
+        metosin/muuntaja {:mvn/version "0.6.11"}
+
+        ;; networking - UDP/TCP/HTTP streaming
+        aleph/aleph {:mvn/version "0.9.7"}
+        org.clj-commons/byte-streams {:mvn/version "0.3.4"}
+
+        org.clojure/clojure {:mvn/version "1.12.1"}}
+ :aliases
+ {;; Run with clj -T:build function-in-build
+  :build {:deps {io.github.clojure/tools.build {:git/tag "v0.10.9" :git/sha "e405aac"}}
+          :ns-default build}}}

backend/dev.sh

@@ -0,0 +1,10 @@
+#!/bin/sh
+
+# Watch for changes to .clj files and auto-restart the server
+# fd -e clj: Find all files ending in .clj
+# entr -r: Run the command when files change, -r flag restarts the command on re-trigger
+# clojure: Clojure CLI
+# -M: Use the main alias from deps.edn (if defined)
+# -m game-server.main: Run the -main function from game-server.main namespace
+fd -e clj | entr -r clojure -M -m game-server.main
+

backend/docker-compose.yml

@@ -1,8 +0,0 @@
-services:
-  backend:
-    build:
-      context: .
-      dockerfile: Dockerfile
-    container_name: love2d-backend-dev
-    ports:
-      - "8095:8095"

backend/go.mod

@@ -1,16 +0,0 @@
-module love2d_backend
-
-go 1.25.0
-
-require (
-	github.com/codecat/go-libs v0.0.0-20210906174629-ffa6674c8e05
-	github.com/mattn/go-sqlite3 v1.14.32
-)
-
-require (
-	github.com/codecat/go-enet v0.0.0-20250728072647-ae229138f138
-	github.com/fatih/color v1.19.0 // indirect
-	github.com/mattn/go-colorable v0.1.14 // indirect
-	github.com/mattn/go-isatty v0.0.20 // indirect
-	golang.org/x/sys v0.42.0 // indirect
-)

backend/go.sum

@@ -1,15 +0,0 @@
-github.com/codecat/go-enet v0.0.0-20250728072647-ae229138f138 h1:qQaqly9oVi84i4nLWmM551z7kcFZIy5koCLoPwCarGY=
-github.com/codecat/go-enet v0.0.0-20250728072647-ae229138f138/go.mod h1:sXkhNvv8T1d/aPEwipUzk7rGWwGJ3uJST2P/Z0zE0L4=
-github.com/codecat/go-libs v0.0.0-20210906174629-ffa6674c8e05 h1:JSfDXHJvrIpQ8Agy//yoIlGpfIprTCDUytmf68fd/Lc=
-github.com/codecat/go-libs v0.0.0-20210906174629-ffa6674c8e05/go.mod h1:xJW98cHEb+Kbuu0qmoKzExh3blthZqojIYOFo27VgvE=
-github.com/fatih/color v1.19.0 h1:Zp3PiM21/9Ld6FzSKyL5c/BULoe/ONr9KlbYVOfG8+w=
-github.com/fatih/color v1.19.0/go.mod h1:zNk67I0ZUT1bEGsSGyCZYZNrHuTkJJB+r6Q9VuMi0LE=
-github.com/mattn/go-colorable v0.1.14 h1:9A9LHSqF/7dyVVX6g0U9cwm9pG3kP9gSzcuIPHPsaIE=
-github.com/mattn/go-colorable v0.1.14/go.mod h1:6LmQG8QLFO4G5z1gPvYEzlUgJ2wF+stgPZH1UqBm1s8=
-github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
-github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
-github.com/mattn/go-sqlite3 v1.14.32 h1:JD12Ag3oLy1zQA+BNn74xRgaBbdhbNIDYvQUEuuErjs=
-github.com/mattn/go-sqlite3 v1.14.32/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=
-golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.42.0 h1:omrd2nAlyT5ESRdCLYdm3+fMfNFE/+Rf4bDIQImRJeo=
-golang.org/x/sys v0.42.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=

backend/main.go

@@ -1,76 +0,0 @@
-package main
-
-import (
-	_ "embed"
-	"log/slog"
-	"os"
-
-	enet "github.com/codecat/go-enet"
-	_ "github.com/mattn/go-sqlite3"
-)
-
-func main() {
-	port := uint16(8095)
-	logger := slog.New(slog.NewJSONHandler(os.Stdout, nil))
-	slog.SetDefault(logger)
-
-	// Initialize enet
-	slog.Info("Initializing E-Net Server", "port", port)
-	enet.Initialize()
-
-	// Create a host listening on 0.0.0.0:8095
-	host, err := enet.NewHost(enet.NewListenAddress(port), 32, 1, 0, 0)
-	if err != nil {
-		slog.Error("Couldn't create host", "error", err)
-		return
-	}
-	slog.Info("Server started", "port", port)
-
-	// The event loop
-	for true {
-		// Wait until the next event
-		ev := host.Service(1000)
-
-		// Do nothing if we didn't get any event
-		if ev.GetType() == enet.EventNone {
-			continue
-		}
-
-		switch ev.GetType() {
-		case enet.EventConnect: // A new peer has connected
-			slog.Info("New peer connected", "address", ev.GetPeer().GetAddress())
-
-		case enet.EventDisconnect: // A connected peer has disconnected
-			slog.Info("Peer disconnected", "address", ev.GetPeer().GetAddress())
-
-		case enet.EventReceive: // A peer sent us some data
-			// Get the packet
-			packet := ev.GetPacket()
-
-			// We must destroy the packet when we're done with it
-			defer packet.Destroy()
-
-			// Get the bytes in the packet
-			packetBytes := packet.GetData()
-
-			// Respond "pong" to "ping"
-			if string(packetBytes) == "ping" {
-				ev.GetPeer().SendString("pong", ev.GetChannelID(), enet.PacketFlagReliable)
-				continue
-			}
-
-			// Disconnect the peer if they say "bye"
-			if string(packetBytes) == "bye" {
-				slog.Info("Peer sent bye, disconnecting")
-				ev.GetPeer().Disconnect(0)
-				continue
-			}
-		}
-	}
-
-	// Destroy the host when we're done with it
-	host.Destroy()
-
-	// Uninitialize enet
-	enet.Deinitialize()
-}

backend/src/game_server/main.clj

@@ -0,0 +1,145 @@
+(ns game-server.main
+  (:require
+   [aleph.udp :as udp]
+   [manifold.stream :as s]
+   [clj-commons.byte-streams :as bs]
+   [taoensso.telemere :as t]
+   [clojure.pprint :refer [pprint]]
+   [clojure.string :as str])
+  (:import (java.security MessageDigest))
+  (:gen-class))
+
+;; UDP examples
+;; - https://gist.github.com/crosstyan/8a87ebdb0c23e549b1c75e9e4013ffa5
+
+(def port 9999)
+(def players (atom {})) ; client registry: {player-id {:host ... :port ...}}
+(def games (atom {:by-id {} :all []}))
+
+;; Global socket reference for sending
+(def server-socket (atom nil))
+
+;; (defn parse-position-msg
+;;   "Parse: 'player-id:x:y' format"
+;;   [msg-str]
+;;   (try
+;;     (let [[player-id x y] (str/split msg-str #":")]
+;;       {:player-id (Integer/parseInt player-id)
+;;        :x (Double/parseDouble x)
+;;        :y (Double/parseDouble y)})
+;;     (catch Exception e
+;;       (t/log! {:level :warn :data {:msg msg-str :error (str e)}} "Failed to parse message")
+;;       nil)))
+;;
+
+;; (if waiting-game
+  ;;     (swap! games (fn [state]
+  ;;       (let )
+
+  ;;       :by-id (assoc (:by-id state) player-id {:player-1 }
+
+  ;;       (-> (:by-id state)
+  ;;                  (assoc player-id waiting-game))
+  ;;       :waiting (disj (:waiting state) waiting-game)
+  ;;       :all (conj (:all state) waiting-game)
+  ;;     })))
+
+;; (defn get-game-by-player-id [player-id]
+;;   (first (filter (fn [game] (or (= (:player-1 game) player-id) (= (:player-2 game) player-id))) @games)))
+
+;; (defn get-waiting-game []
+;;   (first (filter (fn [game] (nil? (:player-2 game))) @games)))
+
+;; (defn join-waiting-game! [player-id other-player-id]
+;;   (if-let [waiting-game (get-game-by-player-id other-player-id)]
+;;     (swap! games update-in [(.indexOf @games waiting-game)] assoc :player-2 player-id)
+;;     (swap! games conj {:player-1 player-id :player-2 nil})))
+
+(defn md5 [s]
+  (let [md (MessageDigest/getInstance "MD5")
+        digest (.digest md (.getBytes s))]
+    (apply str (map #(format "%02x" %) digest))))
+
+(defn send-to-player
+  "Send a UDP packet to a player"
+  [player-id message]
+  (if-let [player (get @players player-id)]
+    (try
+      (s/put! @server-socket
+              {:host (:host player)
+               :port (:port player)
+               :message message})
+      (catch Exception e
+        (t/log! {:level :warn :data {:player-id player-id :error (str e)}} "Failed to send to player")))
+    (t/log! {:level :warn :data {:player-id player-id}} "Player not found")))
+
+(defn join-game! [player-id]
+  (let [waiting-game
+        (some-> (first (filter (fn [game] (nil? (:player-2 game))) (@games :all)))
+                (assoc :player-2 player-id))
+        other-player-id (:player-1 waiting-game)
+        new-game {:player-1 player-id :player-2 nil}]
+    (if waiting-game
+      (do
+        (swap! games (fn [state]
+                       {:by-id
+                        (-> (:by-id state)
+                            (assoc player-id waiting-game)
+                            (assoc other-player-id waiting-game))
+                        :all (map (fn [game] (if (= (:player-1 game) other-player-id)
+                                               waiting-game
+                                               game)) (:all state))}))
+        (send-to-player other-player-id "READY_TO_PLAY")
+        (send-to-player player-id "READY_TO_PLAY"))
+      (do
+        (swap! games (fn [state]
+                       {:by-id (assoc (:by-id state) player-id new-game)
+                        :all (conj (:all state) new-game)}))
+        (send-to-player player-id "WAIT")))))
+
+(defn register-player! [host port]
+  (let [player-id (md5 (str host port))]
+    (swap! players assoc player-id {:host host :port port})
+    (t/log! {:level :info :data {:player-id player-id}} "Player registered")
+    (join-game! player-id)
+    (pprint {:games @games :players @players})))
+
+;; (defn broadcast-to-others [from-player-id position-data]
+;;   "Send position to all other players"
+;;   (let [other-players (dissoc @players from-player-id)
+;;         msg (str from-player-id ":" (:x position-data) ":" (:y position-data))]
+;;     (doseq [[pid _] other-players]
+;;       (send-to-player pid msg))))
+
+(defn parse-packet [packet]
+  (let [host (-> packet (:sender) (bean) (:address) (bean) (:hostAddress))
+        port (-> packet (:sender) (bean) (:port))
+        vector-msg (-> packet (:message) (vec))
+        string-msg (bs/to-string (:message packet))
+        msg-parts (str/split string-msg #"#")]
+    {:host    host
+     :port    port
+     :msg (:message packet)
+     :msg-vec  vector-msg
+     :msg-string  string-msg
+     :msg-parts msg-parts}))
+
+(defn packet-consumer [packet]
+  (t/log! {:level :info :data {:packet packet}} "Consuming packet")
+  (case (first (:msg-parts packet))
+    "REGISTER" (register-player! (:host packet) (:port packet))))
+
+(defn start-server [port]
+  (let [socket @(udp/socket {:port port})]
+    (reset! server-socket socket)
+    (t/log! {:level :info :data {:port port}} "UDP server listening")
+
+    (->> socket
+         (s/map  parse-packet)
+         (s/consume packet-consumer))
+    socket))
+
+(defn -main []
+  (t/log! {:level :info :data {:port port}} "Game server starting")
+  (start-server port)
+  @(promise)) ;; keep server running

backend/test-server.sh

@@ -0,0 +1,48 @@
+#!/bin/bash
+
+# Simple UDP test script for the game server
+# Sends registration and position updates to simulate two players
+
+HOST="localhost"
+PORT=9999
+
+echo "Testing game server at $HOST:$PORT"
+echo ""
+
+# Helper to send UDP packet
+send_udp() {
+  local msg="$1"
+  echo "Sending: $msg"
+  echo -n "$msg" | nc -u -w1 "$HOST" "$PORT"
+}
+
+echo "=== Registering Player 1 ==="
+send_udp "REGISTER"
+nc -u -l 0.0.0.0 12345
+# sleep 0.5
+
+# echo ""
+# echo "=== Registering Player 2 ==="
+# send_udp "register:2"
+# sleep 0.5
+
+# echo ""
+# echo "=== Player 1 moving around ==="
+# for i in {1..3}; do
+#   x=$((100 + i * 10))
+#   y=$((200 + i * 5))
+#   send_udp "1:$x:$y"
+#   sleep 0.3
+# done
+
+# echo ""
+# echo "=== Player 2 moving around ==="
+# for i in {1..3}; do
+#   x=$((300 - i * 10))
+#   y=$((150 + i * 20))
+#   send_udp "2:$x:$y"
+#   sleep 0.3
+# done
+
+echo ""
+echo "Done!"