Initial Commit

.gitignore

@@ -0,0 +1,118 @@
+# User-specific stuff
+.idea/
+
+*.iml
+*.ipr
+*.iws
+
+# IntelliJ
+out/
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Compiled class file
+*.class
+
+# Log file
+*.log
+
+# BlueJ files
+*.ctxt
+
+# Package Files #
+*.jar
+*.war
+*.nar
+*.ear
+*.zip
+*.tar.gz
+*.rar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*
+
+*~
+
+# temporary files which can be created if a process still has a handle open of a deleted file
+.fuse_hidden*
+
+# KDE directory preferences
+.directory
+
+# Linux trash folder which might appear on any partition or disk
+.Trash-*
+
+# .nfs files are created when an open file is removed but is still being accessed
+.nfs*
+
+# General
+.DS_Store
+.AppleDouble
+.LSOverride
+
+# Icon must end with two \r
+Icon
+
+# Thumbnails
+._*
+
+# Files that might appear in the root of a volume
+.DocumentRevisions-V100
+.fseventsd
+.Spotlight-V100
+.TemporaryItems
+.Trashes
+.VolumeIcon.icns
+.com.apple.timemachine.donotpresent
+
+# Directories potentially created on remote AFP share
+.AppleDB
+.AppleDesktop
+Network Trash Folder
+Temporary Items
+.apdisk
+
+# Windows thumbnail cache files
+Thumbs.db
+Thumbs.db:encryptable
+ehthumbs.db
+ehthumbs_vista.db
+
+# Dump file
+*.stackdump
+
+# Folder config file
+[Dd]esktop.ini
+
+# Recycle Bin used on file shares
+$RECYCLE.BIN/
+
+# Windows Installer files
+*.cab
+*.msi
+*.msix
+*.msm
+*.msp
+
+# Windows shortcuts
+*.lnk
+
+.gradle
+build/
+
+# Ignore Gradle GUI config
+gradle-app.setting
+
+# Cache of project
+.gradletasknamecache
+
+**/build/
+
+# Common working directory
+run/
+
+# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
+!gradle-wrapper.jar

LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2022 
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

build.gradle

@@ -0,0 +1,81 @@
+plugins {
+    id 'fabric-loom' version '1.0-SNAPSHOT'
+    id 'maven-publish'
+}
+
+version = project.mod_version
+group = project.maven_group
+
+repositories {
+    // Add repositories to retrieve artifacts from in here.
+    // You should only use this when depending on other mods because
+    // Loom adds the essential maven repositories to download Minecraft and libraries from automatically.
+    // See https://docs.gradle.org/current/userguide/declaring_repositories.html
+    // for more information about repositories.
+}
+
+dependencies {
+    // To change the versions see the gradle.properties file
+    minecraft "com.mojang:minecraft:${project.minecraft_version}"
+    mappings "net.fabricmc:yarn:${project.yarn_mappings}:v2"
+    modImplementation "net.fabricmc:fabric-loader:${project.loader_version}"
+
+    // Fabric API. This is technically optional, but you probably want it anyway.
+    modImplementation "net.fabricmc.fabric-api:fabric-api:${project.fabric_version}"
+}
+
+processResources {
+    inputs.property "version", project.version
+    filteringCharset "UTF-8"
+
+    filesMatching("fabric.mod.json") {
+        expand "version": project.version
+    }
+}
+
+def targetJavaVersion = 17
+tasks.withType(JavaCompile).configureEach {
+    // ensure that the encoding is set to UTF-8, no matter what the system default is
+    // this fixes some edge cases with special characters not displaying correctly
+    // see http://yodaconditions.net/blog/fix-for-java-file-encoding-problems-with-gradle.html
+    // If Javadoc is generated, this must be specified in that task too.
+    it.options.encoding = "UTF-8"
+    if (targetJavaVersion >= 10 || JavaVersion.current().isJava10Compatible()) {
+        it.options.release = targetJavaVersion
+    }
+}
+
+java {
+    def javaVersion = JavaVersion.toVersion(targetJavaVersion)
+    if (JavaVersion.current() < javaVersion) {
+        toolchain.languageVersion = JavaLanguageVersion.of(targetJavaVersion)
+    }
+    archivesBaseName = project.archives_base_name
+    // Loom will automatically attach sourcesJar to a RemapSourcesJar task and to the "build" task
+    // if it is present.
+    // If you remove this line, sources will not be generated.
+    withSourcesJar()
+}
+
+jar {
+    from("LICENSE") {
+        rename { "${it}_${project.archivesBaseName}" }
+    }
+}
+
+// configure the maven publication
+publishing {
+    publications {
+        mavenJava(MavenPublication) {
+            from components.java
+        }
+    }
+
+    // See https://docs.gradle.org/current/userguide/publishing_maven.html for information on how to set up publishing.
+    repositories {
+        // Add repositories to publish to here.
+        // Notice: This block does NOT have the same function as the block in the top level.
+        // The repositories here will be used for publishing your artifact, not for
+        // retrieving dependencies.
+    }
+}

gradle.properties

@@ -0,0 +1,14 @@
+# Done to increase the memory available to gradle.
+org.gradle.jvmargs=-Xmx1G
+# Fabric Properties
+# check these on https://modmuss50.me/fabric.html
+minecraft_version=1.19.2
+yarn_mappings=1.19.2+build.28
+loader_version=0.14.10
+# Mod Properties
+mod_version=1.0-SNAPSHOT
+maven_group=org.muellerssoftware
+archives_base_name=OpenProximityChatFabric
+# Dependencies
+# check this on https://modmuss50.me/fabric.html
+fabric_version=0.64.0+1.19.2

gradlew

@@ -0,0 +1,234 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original 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 POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( 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" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

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

settings.gradle

@@ -0,0 +1,9 @@
+pluginManagement {
+    repositories {
+        maven {
+            name = 'Fabric'
+            url = 'https://maven.fabricmc.net/'
+        }
+        gradlePluginPortal()
+    }
+}

src/main/java/org/muellerssoftware/openproximitychatfabric/OPCFabric.java

@@ -0,0 +1,18 @@
+package org.muellerssoftware.openproximitychatfabric;
+
+import net.fabricmc.api.ModInitializer;
+import net.minecraft.entity.player.PlayerEntity;
+import org.muellerssoftware.openproximitychatfabric.connect.Stage1HandshakeBuilder;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.HashMap;
+
+public class OPCFabric implements ModInitializer {
+    public static HashMap<PlayerEntity, Stage1HandshakeBuilder> tracked_players;
+    public static final Logger LOGGER = LoggerFactory.getLogger("OPCFabric");
+    @Override
+    public void onInitialize() {
+
+    }
+}

src/main/java/org/muellerssoftware/openproximitychatfabric/client/OPCFabricClient.java

@@ -0,0 +1,13 @@
+package org.muellerssoftware.openproximitychatfabric.client;
+
+import net.fabricmc.api.ClientModInitializer;
+import net.fabricmc.api.EnvType;
+import net.fabricmc.api.Environment;
+
+@Environment(EnvType.CLIENT)
+public class OPCFabricClient implements ClientModInitializer {
+    @Override
+    public void onInitializeClient() {
+
+    }
+}

src/main/java/org/muellerssoftware/openproximitychatfabric/connect/Connection.java

@@ -0,0 +1,5 @@
+package org.muellerssoftware.openproximitychatfabric.connect;
+
+public class Connection {
+
+}

src/main/java/org/muellerssoftware/openproximitychatfabric/connect/HandshakeException.java

@@ -0,0 +1,7 @@
+package org.muellerssoftware.openproximitychatfabric.connect;
+
+public class HandshakeException extends Exception {
+    HandshakeException(String message) {
+        super(message);
+    }
+}

src/main/java/org/muellerssoftware/openproximitychatfabric/connect/Stage1HandshakeBuilder.java

@@ -0,0 +1,137 @@
+package org.muellerssoftware.openproximitychatfabric.connect;
+
+import net.minecraft.entity.player.PlayerEntity;
+import org.jetbrains.annotations.Nullable;
+import org.muellerssoftware.openproximitychatfabric.OPCFabric;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+
+import static java.lang.Math.abs;
+
+public class Stage1HandshakeBuilder {
+    private static class Movement {
+        double deltaYaw;
+        double deltaPitch;
+
+        Movement(double deltaYaw, double deltaPitch) {
+            this.deltaPitch = deltaPitch;
+            this.deltaYaw = deltaYaw;
+        }
+
+        public Movement getOpposite() {
+            return new Movement(-this.deltaYaw, -this.deltaPitch);
+        }
+    }
+
+    public enum ConnectionFilterType {
+        Friend,
+        Everyone
+    }
+
+    public static class Stage1Handshake {
+        private ConnectionFilterType filterType;
+        private PlayerEntity player;
+
+        public PlayerEntity getPlayer() {
+            return player;
+        }
+
+        public ConnectionFilterType getFilterType() {
+            return filterType;
+        }
+    }
+
+    private ArrayList<Movement> movements = new ArrayList<>();
+    private PlayerEntity player;
+
+    private static final Movement[] MAGIC_MOVES = {
+            new Movement(0.031, 0.041),
+            new Movement(-0.059, -0.026),
+            new Movement(0.053, 0.058),
+            new Movement(-0.097, -0.093),
+            new Movement(0.023, 0.084),
+            new Movement(0.049, -0.064)
+    };
+
+    private static final Movement[] FRIENDSHIP_MOVES = {
+            new Movement(0.062, 0.064),
+            new Movement(-0.062, -0.064)
+    };
+
+    private static final Movement[] OMNIFRIEND_MOVES = {
+            new Movement(0.033, 0.083),
+            new Movement(-0.033, -0.083)
+    };
+
+    public static final Movement[] CHECKSUM_PRECURSOR = {
+            new Movement(0.027, 0.095),
+            new Movement(-0.027, -0.095)
+    };
+
+    public Stage1HandshakeBuilder withPlayer(PlayerEntity player) {
+        this.player = player;
+        return this;
+    }
+
+    public Stage1HandshakeBuilder addDelta(double yaw, double pitch) {
+        this.movements.add(new Movement(yaw, pitch));
+        return this;
+    }
+
+    @Nullable
+    public Stage1Handshake tryBuild() throws HandshakeException {
+        if (this.movements.size() < 24) {
+            throw new HandshakeException("Too few stored head movements (need at least 24)");
+        }
+
+        ArrayList<Movement> handshake = null;
+
+        for (int i = 0; i < this.movements.size(); i++) {
+            if (Arrays.equals(this.movements.subList(i, i + 6).toArray(), MAGIC_MOVES)) {
+                // Found start of handshake
+                handshake = new ArrayList<>(this.movements.subList(i, i + 12));
+                break;
+            }
+        }
+
+        if (handshake != null) {
+            OPCFabric.LOGGER.debug("Found handshake in {}'s head movements", this.player.getName().asTruncatedString(64));
+            Stage1Handshake output = new Stage1Handshake();
+            if (Arrays.equals(handshake.subList(6, 8).toArray(), FRIENDSHIP_MOVES)) {
+                output.filterType = ConnectionFilterType.Friend;
+            }
+            else if (Arrays.equals(handshake.subList(6, 8).toArray(), OMNIFRIEND_MOVES)){
+                output.filterType = ConnectionFilterType.Everyone;
+            }
+
+            if (this.player != null) {
+                output.player = this.player;
+            }
+            else {
+                throw new HandshakeException("Player not set in Stage 1 Handshake");
+            }
+
+            if (!Arrays.equals(handshake.subList(8, 10).toArray(), CHECKSUM_PRECURSOR)) {
+                return null;
+            }
+
+            Movement totalMovement = new Movement(0, 0);
+
+            handshake.forEach(movement -> {
+                totalMovement.deltaYaw += abs(movement.deltaYaw);
+                totalMovement.deltaPitch += abs(movement.deltaPitch);
+            });
+
+            if (totalMovement != handshake.get(10) || !totalMovement.getOpposite().equals(handshake.get(11))) {
+                return null;
+            }
+            else {
+                return output;
+            }
+        }
+        else {
+            return null;
+        }
+    }
+}

src/main/java/org/muellerssoftware/openproximitychatfabric/connect/Stage2HandshakeBuilder.java

@@ -0,0 +1,29 @@
+package org.muellerssoftware.openproximitychatfabric.connect;
+
+import net.minecraft.server.MinecraftServer;
+import net.minecraft.server.network.ServerPlayerEntity;
+
+public class Stage2HandshakeBuilder {
+    private ServerPlayerEntity target_player;
+    private MinecraftServer target_server;
+
+    public Stage2HandshakeBuilder() {
+
+    }
+
+    public Stage2HandshakeBuilder withPlayer(ServerPlayerEntity player) {
+        target_player = player;
+        return this;
+    }
+
+    public Stage2HandshakeBuilder onServer(MinecraftServer server) {
+        target_server = server;
+        return this;
+    }
+
+    Connection connect() {
+
+
+        return new Connection();
+    }
+}

src/main/java/org/muellerssoftware/openproximitychatfabric/mixins/ClientPlayNetworkHandlerMixin.java

@@ -0,0 +1,32 @@
+package org.muellerssoftware.openproximitychatfabric.mixins;
+
+import net.minecraft.client.network.ClientPlayNetworkHandler;
+import net.minecraft.entity.Entity;
+import net.minecraft.entity.player.PlayerEntity;
+import net.minecraft.network.packet.s2c.play.EntityS2CPacket;
+import org.muellerssoftware.openproximitychatfabric.OPCFabric;
+import org.muellerssoftware.openproximitychatfabric.connect.Stage1HandshakeBuilder;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+import org.spongepowered.asm.mixin.injection.callback.LocalCapture;
+
+@Mixin(ClientPlayNetworkHandler.class)
+public abstract class ClientPlayNetworkHandlerMixin {
+    @Inject(method = "onEntity(Lnet/minecraft/network/packet/s2c/play/EntityS2CPacket;)V", at = @At(value = "TAIL", target = "Lnet/minecraft/network/packet/s2c/play/EntityS2CPacket;hasRotation()Z"), locals = LocalCapture.CAPTURE_FAILHARD)
+    private void entityMixin(EntityS2CPacket packet, CallbackInfo ci, Entity entity) {
+        if (packet.hasRotation()) {
+            if (entity.isPlayer()) {
+                PlayerEntity player = (PlayerEntity)entity;
+                if (packet.hasRotation()) {
+                    if (!OPCFabric.tracked_players.containsKey(player)) {
+                        OPCFabric.tracked_players.put(player, new Stage1HandshakeBuilder().withPlayer(player));
+                    }
+                    OPCFabric.tracked_players.get(player).addDelta(packet.getYaw(), packet.getPitch());
+                }
+            }
+        }
+    }
+}

src/main/resources/OpenProximityChatFabric.mixins.json

@@ -0,0 +1,14 @@
+{
+  "required": true,
+  "minVersion": "0.8",
+  "package": "org.muellerssoftware.openproximitychatfabric.mixins",
+  "compatibilityLevel": "JAVA_17",
+  "mixins": [
+  ],
+  "client": [
+    "ClientPlayNetworkHandlerMixin"
+  ],
+  "injectors": {
+    "defaultRequire": 1
+  }
+}

src/main/resources/fabric.mod.json

@@ -0,0 +1,28 @@
+{
+  "schemaVersion": 1,
+  "id": "openproximitychat",
+  "version": "${version}",
+  "name": "OpenProximityChat (Fabric)",
+  "description": "",
+  "authors": [],
+  "contact": {},
+  "license": "MIT",
+  "icon": "assets/OpenProximityChatFabric/icon.png",
+  "environment": "*",
+  "entrypoints": {
+    "client": [
+      "org.muellerssoftware.openproximitychatfabric.client.OPCFabricClient"
+    ],
+    "main": [
+      "org.muellerssoftware.openproximitychatfabric.OPCFabric"
+    ]
+  },
+  "mixins": [
+    "OpenProximityChatFabric.mixins.json"
+  ],
+  "depends": {
+    "fabricloader": ">=0.14.10",
+    "fabric": "*",
+    "minecraft": "1.19.2"
+  }
+}