commit 1d35ea2b492bd37c1995b275ad7a3141a8566162
Author: Oliver Rümpelein <oli_r@fg4f.de>
Date:   Sat Sep 25 12:24:28 2021 +0200

    Initial MVP

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..1886ba5
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+/build/
+.idea/
+.gradle/
diff --git a/build.gradle.kts b/build.gradle.kts
new file mode 100644
index 0000000..634e301
--- /dev/null
+++ b/build.gradle.kts
@@ -0,0 +1,30 @@
+val ktor_version: String by project
+val kotlin_version: String by project
+val logback_version: String by project
+val kotlinx_html_version: String by project
+
+plugins {
+    application
+    kotlin("jvm") version "1.5.31"
+}
+
+group = "de.pheerai.buzzer"
+version = "0.0.1"
+application {
+    mainClass.set("de.pheerai.buzzer.ApplicationKt")
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation("io.ktor:ktor-server-core:$ktor_version")
+    implementation("io.ktor:ktor-websockets:$ktor_version")
+    implementation("org.jetbrains.kotlinx:kotlinx-html-jvm:$kotlinx_html_version")
+    implementation("io.ktor:ktor-html-builder:$ktor_version")
+    implementation("io.ktor:ktor-server-netty:$ktor_version")
+    implementation("ch.qos.logback:logback-classic:$logback_version")
+    testImplementation("io.ktor:ktor-server-tests:$ktor_version")
+    testImplementation("org.jetbrains.kotlin:kotlin-test:$kotlin_version")
+}
diff --git a/gradle.properties b/gradle.properties
new file mode 100644
index 0000000..098cf9e
--- /dev/null
+++ b/gradle.properties
@@ -0,0 +1,5 @@
+ktor_version=1.6.3
+kotlin_version=1.5.31
+logback_version=1.2.6
+kotlinx_html_version=0.7.3
+kotlin.code.style=official
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..7454180
Binary files /dev/null and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..69a9715
--- /dev/null
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/gradlew b/gradlew
new file mode 100755
index 0000000..744e882
--- /dev/null
+++ b/gradlew
@@ -0,0 +1,185 @@
+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MSYS* | MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
new file mode 100644
index 0000000..107acd3
--- /dev/null
+++ b/gradlew.bat
@@ -0,0 +1,89 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/settings.gradle.kts b/settings.gradle.kts
new file mode 100644
index 0000000..2b5cd2c
--- /dev/null
+++ b/settings.gradle.kts
@@ -0,0 +1 @@
+rootProject.name = "server"
diff --git a/src/main/kotlin/de/pheerai/buzzer/Application.kt b/src/main/kotlin/de/pheerai/buzzer/Application.kt
new file mode 100644
index 0000000..8a71b74
--- /dev/null
+++ b/src/main/kotlin/de/pheerai/buzzer/Application.kt
@@ -0,0 +1,11 @@
+package de.pheerai.buzzer
+
+import de.pheerai.buzzer.plugins.*
+import io.ktor.server.engine.*
+import io.ktor.server.netty.*
+
+fun main() {
+    embeddedServer(Netty, port = 8888, host = "0.0.0.0") {
+        configureSockets()
+    }.start(wait = true)
+}
diff --git a/src/main/kotlin/de/pheerai/buzzer/data/InlineClasses.kt b/src/main/kotlin/de/pheerai/buzzer/data/InlineClasses.kt
new file mode 100644
index 0000000..6d4b2bd
--- /dev/null
+++ b/src/main/kotlin/de/pheerai/buzzer/data/InlineClasses.kt
@@ -0,0 +1,9 @@
+package de.pheerai.buzzer.data
+
+import io.ktor.http.cio.websocket.*
+
+
+@JvmInline
+value class PlayerSocket(val session: WebSocketSession)
+@JvmInline
+value class GameMasterSocket(val session: WebSocketSession)
diff --git a/src/main/kotlin/de/pheerai/buzzer/plugins/Sockets.kt b/src/main/kotlin/de/pheerai/buzzer/plugins/Sockets.kt
new file mode 100644
index 0000000..5e430eb
--- /dev/null
+++ b/src/main/kotlin/de/pheerai/buzzer/plugins/Sockets.kt
@@ -0,0 +1,128 @@
+package de.pheerai.buzzer.plugins
+
+import de.pheerai.buzzer.data.GameMasterSocket
+import de.pheerai.buzzer.data.PlayerSocket
+import io.ktor.application.*
+import io.ktor.html.*
+import io.ktor.http.cio.websocket.*
+import io.ktor.http.content.*
+import io.ktor.routing.*
+import io.ktor.websocket.*
+import kotlinx.coroutines.isActive
+import kotlinx.html.*
+import java.time.Duration
+import java.util.*
+
+fun Application.configureSockets() {
+    install(WebSockets) {
+        pingPeriod = Duration.ofSeconds(15)
+        timeout = Duration.ofSeconds(15)
+        maxFrameSize = Long.MAX_VALUE
+        masking = false
+    }
+
+    routing {
+        val playerSessions = Collections.synchronizedCollection(LinkedList<PlayerSocket>())
+        val gameMasterSessions = Collections.synchronizedCollection(LinkedList<GameMasterSocket>())
+
+        static("/assets") {
+            resources("css")
+            resources("js")
+        }
+
+        get("/") {
+            call.respondHtml {
+                createPlayerDocument()
+            }
+        }
+
+        get("/client/player") {
+            call.respondHtml {
+                createPlayerDocument()
+            }
+        }
+
+        get("/client/master") {
+            call.respondHtml {
+                createAdminDocument()
+            }
+        }
+
+        webSocket("/socket/player") {
+            playerSessions.add(PlayerSocket(this))
+            for (frame in incoming) {
+                when (frame) {
+                    is Frame.Text -> {
+                        val text = frame.readText()
+                        log.info("Username: $text")
+                        gameMasterSessions.filter { it.session.isActive }
+                            .forEach { it.session.send(text) }
+                    }
+                    else -> {}
+                }
+            }
+        }
+
+        webSocket("/socket/master") {
+            gameMasterSessions.add(GameMasterSocket(this))
+            for (frame in incoming) {
+                when (frame) {
+                    is Frame.Text -> {
+                        val text = frame.readText()
+                        playerSessions.filter { it.session.isActive }
+                            .forEach { it.session.send(text) }
+                    }
+                    else -> {}
+                }
+            }
+        }
+    }
+}
+
+fun HTML.createPlayerDocument() {
+    head {
+        meta { charset = "UTF-8" }
+        title { +"JS Client" }
+        link(
+            href = "/assets/player.css",
+            rel = "stylesheet",
+            type = "text/css"
+        )
+        script { src = "https://code.jquery.com/jquery-3.6.0.min.js" }
+        script { src = "/assets/playerClient.js" }
+    }
+    body {
+        div(classes = "parent") {
+            div(classes = "input") {
+                label { +"Player" }
+                div(classes = "bumper") {}
+                input {
+                    id = "username"
+                    placeholder = "<name>"
+                }
+            }
+            button(classes = "submit") {
+                onClick = "sendUsername()"
+                +"I know that!"
+            }
+        }
+    }
+}
+
+fun HTML.createAdminDocument() {
+    head {
+        meta { charset = "UTF-8" }
+        title { +"JS Client" }
+        script { src = "https://code.jquery.com/jquery-3.6.0.min.js" }
+        script { src = "/assets/adminClient.js" }
+    }
+    body {
+        ol {
+            id = "usernames"
+        }
+        button {
+            onClick = "resetReceived()"
+            +"Reset"
+        }
+    }
+}
diff --git a/src/main/resources/css/player.css b/src/main/resources/css/player.css
new file mode 100644
index 0000000..805e368
--- /dev/null
+++ b/src/main/resources/css/player.css
@@ -0,0 +1,59 @@
+body, html {
+    height: 100%;
+    overflow: hidden;
+    font-size: 4vh;
+    box-sizing: border-box;
+    padding: 5px;
+    margin: 0;
+    background-color: #1E1A4A;
+    color: lightgray;
+}
+
+div.parent {
+    display: grid;
+    grid-template-rows: auto 1fr;
+    height: 100%;
+    max-width: 100%;
+}
+
+div.input {
+    border-radius: 50px;
+    max-width: 100%;
+    margin-bottom: 3%;
+    display: grid;
+    grid-template-columns: auto 50px 1fr;
+    background-color: #411C52;
+    padding-left: 20px;
+}
+
+div.input > label {
+    border-bottom-left-radius: 50px;
+    border-top-left-radius: 50px;
+}
+
+div.input > input {
+    max-width: 100%;
+    width: 100%;
+    font-size: 4vh;
+    border-bottom-right-radius: 50px;
+    border-top-right-radius: 50px;
+    background-color: #551D57;
+}
+
+div > .submit {
+    border-radius: 50px;
+    width: 100%;
+    max-width: 100%;
+    font-size: 4vh;
+    height: 100%;
+    border: solid 1px #5B1D4A;
+    background-color: #411C52;
+    color: lightgray;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+}
+
+div > .button:hover {
+    background-color: #5B1D4A;
+}
diff --git a/src/main/resources/js/adminClient.js b/src/main/resources/js/adminClient.js
new file mode 100644
index 0000000..fc8f214
--- /dev/null
+++ b/src/main/resources/js/adminClient.js
@@ -0,0 +1,21 @@
+'use strict';
+
+let adminSocket;
+
+$.when($.ready).then(function () {
+    let protocolPrefix = (window.location.protocol === 'https:') ? 'wss:' : 'ws:';
+    adminSocket = new WebSocket(`${protocolPrefix}//${location.host}/socket/master`);
+
+    adminSocket.addEventListener('message', (ev) => {
+        console.log(`Received: ${ev.data}`)
+        appendUsername(ev.data)
+    });
+});
+
+function appendUsername(username) {
+    $('ol#usernames').append(`<li>${username}</li>`)
+}
+
+function resetReceived() {
+    $('ol#usernames').empty()
+}
diff --git a/src/main/resources/js/playerClient.js b/src/main/resources/js/playerClient.js
new file mode 100644
index 0000000..58db232
--- /dev/null
+++ b/src/main/resources/js/playerClient.js
@@ -0,0 +1,18 @@
+'use strict';
+
+let webSocket;
+
+$.when($.ready).then(function () {
+    let protocolPrefix = (window.location.protocol === 'https:') ? 'wss:' : 'ws:';
+    webSocket = new WebSocket(`${protocolPrefix}//${location.host}/socket/player`);
+});
+
+function sendUsername() {
+    const username = $('#username').val()
+    if (username !== null && username !== '') {
+        console.log(`Username: ${username}`)
+        webSocket.send(username)
+    } else {
+        alert("Please enter a name!")
+    }
+}