From d533ce97bb0b7f8ab37d2ab99965da177a235781 Mon Sep 17 00:00:00 2001
From: Luca Warmenhoven <luca.warmenhoven@hva.nl>
Date: Wed, 8 May 2024 14:40:14 +0200
Subject: [PATCH] Added motion processing, fixed WebSocket packet processing,
 added Vector math to process motion data

---
 .idea/workspace.xml                           |  29 +--
 .../fitbot/util/processing/MotionData.java    |  33 ++--
 .../util/processing/MotionInputStream.java    |  38 ----
 .../util/processing/MotionProcessor.java      |  91 ++++++++++
 .../fitbot/util/processing/Vector3.java       | 165 ++++++++++++++++++
 .../fitbot/util/server/IWebSocketHandler.java |   5 +-
 .../example/fitbot/util/server/WebSocket.java |  70 ++++++++
 .../util/server/WebSocketConnection.java      |  35 ++++
 .../server/WebSocketConnectionHandler.java    | 150 +++++++++++++---
 .../fitbot/WebSocketMessageParsingTest.java   |  37 ++++
 .../Luca/literatuuronderzoek/onderzoek.md     |  22 +++
 11 files changed, 587 insertions(+), 88 deletions(-)
 delete mode 100644 code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionInputStream.java
 create mode 100644 code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/Vector3.java
 create mode 100644 code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocketConnection.java
 create mode 100644 code/src/Fitbot/app/src/test/java/com/example/fitbot/WebSocketMessageParsingTest.java

diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index 22bfcea..fb9da63 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -15,9 +15,14 @@
   </component>
   <component name="ChangeListManager">
     <list default="true" id="00599d5b-7eb5-44da-ad7f-98bf42384c16" name="Changes" comment="Final update onderzoek-formulier.md">
-      <change afterPath="$PROJECT_DIR$/docs/personalDocs/Luca/weekly-reports/sprint-1-week-1.md" afterDir="false" />
-      <change afterPath="$PROJECT_DIR$/docs/personalDocs/Luca/weekly-reports/sprint-1-week-2.md" afterDir="false" />
-      <change beforePath="$PROJECT_DIR$/code/src/Fitbot/app/src/main/java/com/example/fitbot/MainActivity.java" beforeDir="false" afterPath="$PROJECT_DIR$/code/src/Fitbot/app/src/main/java/com/example/fitbot/MainActivity.java" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocketConnection.java" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionData.java" beforeDir="false" afterPath="$PROJECT_DIR$/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionData.java" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionInputStream.java" beforeDir="false" />
+      <change beforePath="$PROJECT_DIR$/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionProcessor.java" beforeDir="false" afterPath="$PROJECT_DIR$/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionProcessor.java" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/IWebSocketHandler.java" beforeDir="false" afterPath="$PROJECT_DIR$/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/IWebSocketHandler.java" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocket.java" beforeDir="false" afterPath="$PROJECT_DIR$/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocket.java" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocketConnectionHandler.java" beforeDir="false" afterPath="$PROJECT_DIR$/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocketConnectionHandler.java" afterDir="false" />
     </list>
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
@@ -70,10 +75,10 @@
   <component name="MarkdownSettingsMigration">
     <option name="stateVersion" value="1" />
   </component>
-  <component name="ProjectColorInfo"><![CDATA[{
-  "customColor": "",
-  "associatedIndex": 7
-}]]></component>
+  <component name="ProjectColorInfo">{
+  &quot;customColor&quot;: &quot;&quot;,
+  &quot;associatedIndex&quot;: 7
+}</component>
   <component name="ProjectId" id="2fE3N2CwEPDo9wBtexBLxU20tCJ" />
   <component name="ProjectLevelVcsManager">
     <ConfirmationsSetting value="2" id="Add" />
@@ -85,13 +90,16 @@
   <component name="PropertiesComponent"><![CDATA[{
   "keyToString": {
     "RunOnceActivity.OpenProjectViewOnStart": "true",
-    "git-widget-placeholder": "Merging main",
+    "RunOnceActivity.ShowReadmeOnStart": "true",
+    "git-widget-placeholder": "44-als-gebruiker-wil-ik-dat-ik-feedback-krijg-als-mijn-bewegingen-niet-op…-weet",
     "kotlin-language-version-configured": "true",
+    "last_opened_file_path": "/Users/lucawarm/Jetbrains/Android Studio/muupooviixee66",
     "node.js.detected.package.eslint": "true",
     "node.js.detected.package.tslint": "true",
     "node.js.selected.package.eslint": "(autodetect)",
     "node.js.selected.package.tslint": "(autodetect)",
     "nodejs_package_manager_path": "npm",
+    "settings.editor.selected.configurable": "preferences.pluginManager",
     "vue.rearranger.settings.migration": "true"
   }
 }]]></component>
@@ -118,10 +126,7 @@
       <option name="INSPECTION_WITHOUT_ACTIVITY_RESTART" value="false" />
       <option name="TARGET_SELECTION_MODE" value="SHOW_DIALOG" />
       <option name="DEBUGGER_TYPE" value="Java" />
-      <Java>
-        <option name="ATTACH_ON_WAIT_FOR_DEBUGGER" value="false" />
-        <option name="DEBUG_SANDBOX_SDK" value="false" />
-      </Java>
+      <Java />
       <Profilers>
         <option name="ADVANCED_PROFILING_ENABLED" value="false" />
         <option name="STARTUP_PROFILING_ENABLED" value="false" />
diff --git a/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionData.java b/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionData.java
index 42c346c..8278192 100644
--- a/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionData.java
+++ b/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionData.java
@@ -1,14 +1,11 @@
 package com.example.fitbot.util.processing;
 
+import java.util.Objects;
+
 public class MotionData {
 
     // Data of the motion sensor
-    public float accelerationX;
-    public float accelerationY;
-    public float accelerationZ;
-    public float rotationX;
-    public float rotationY;
-    public float rotationZ;
+    public Vector3 acceleration, rotation;
 
     // Delimiter for the data received from the motion sensor
     private static final String DATA_DELIMITER = ";";
@@ -24,12 +21,19 @@ public class MotionData {
      * @param rotationZ     The rotation in the Z axis in degrees.
      */
     public MotionData(float accelerationX, float accelerationY, float accelerationZ, float rotationX, float rotationY, float rotationZ) {
-        this.accelerationX = accelerationX;
-        this.accelerationY = accelerationY;
-        this.accelerationZ = accelerationZ;
-        this.rotationX = rotationX;
-        this.rotationY = rotationY;
-        this.rotationZ = rotationZ;
+        this.acceleration = new Vector3(accelerationX, accelerationY, accelerationZ);
+        this.rotation = new Vector3(rotationX, rotationY, rotationZ);
+    }
+
+    /**
+     * Constructor for the MotionData class.
+     *
+     * @param acceleration The acceleration vector in m/s^2.
+     * @param rotation     The rotation vector in degrees.
+     */
+    public MotionData(Vector3 acceleration, Vector3 rotation) {
+        this.acceleration = acceleration;
+        this.rotation = rotation;
     }
 
     /**
@@ -41,7 +45,12 @@ public class MotionData {
      * @return An instance of MotionData.
      */
     public static MotionData decode(String data) {
+        Objects.requireNonNull(data); // Ensure data is not null
+
         String[] parts = data.split(DATA_DELIMITER);
+        if (parts.length != 6)
+            return null;
+
         return new MotionData(
                 Float.parseFloat(parts[0]),
                 Float.parseFloat(parts[1]),
diff --git a/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionInputStream.java b/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionInputStream.java
deleted file mode 100644
index a4db7f6..0000000
--- a/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionInputStream.java
+++ /dev/null
@@ -1,38 +0,0 @@
-package com.example.fitbot.util.processing;
-
-import com.example.fitbot.util.server.WebSocket;
-
-import java.io.InputStream;
-
-/**
- * Class representing the input stream of the motion sensor.
- * This class will be responsible for reading the data from
- * the motion sensor and processing it, by creating a
- * server and starting a WebSocket connection with the ESP32.
- */
-public class MotionInputStream extends InputStream {
-
-    /**
-     * Function for starting the listening process
-     * of the motion sensor. This function will
-     * @return An instance of MotionInputStream.
-     */
-    public static MotionInputStream startListening()
-    {
-        // Create socket server
-        WebSocket socket = WebSocket.createServer(80);
-
-        // Check if the socket
-        if ( socket != null )
-        {
-            socket.startListening();
-        }
-        return null;
-    }
-
-
-    @Override
-    public int read() {
-        return 0;
-    }
-}
diff --git a/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionProcessor.java b/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionProcessor.java
index 6726312..9711e10 100644
--- a/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionProcessor.java
+++ b/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/MotionProcessor.java
@@ -1,4 +1,95 @@
 package com.example.fitbot.util.processing;
 
+import android.util.Log;
+
+import com.example.fitbot.util.server.IWebSocketHandler;
+import com.example.fitbot.util.server.WebSocket;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.util.ArrayList;
+import java.util.List;
+
 public class MotionProcessor {
+
+    private static final int MAX_PATH_LENGTH = 100;
+    public static final String DELIMITER = ";";
+
+    private final List<MotionData> motionData = new ArrayList<>();
+    private final Vector3[] relativePath = new Vector3[MAX_PATH_LENGTH];
+    private Vector3 ZERO = new Vector3(0, 0, 0);
+    private int sampleRate = 1;
+
+    public MotionProcessor() {}
+
+
+    /**
+     * Function for starting the listening process
+     * of the motion sensor. This function will create
+     * a new WebSocket server and start listening for
+     * incoming connections.
+     */
+    public void startListening() {
+        // Create socket server
+        WebSocket socket = WebSocket.createServer(80);
+
+        // Check if the socket
+        if (socket != null) {
+            // Update event handler to match our functionality.
+            socket.setEventHandler(new IWebSocketHandler() {
+                @Override
+                public void onMessageReceived(WebSocket.Message message, WebSocket.MessageReply replier) {
+                    parsePacket(message.message);
+                }
+            });
+            socket.startListening();
+        }
+    }
+
+    /**
+     * Function for parsing arbitrary packet data.
+     * @param data The data to parse.
+     */
+    private void parsePacket(@NotNull String data) {
+        // If the message starts with 'data', it's a data packet.
+        if ( data.startsWith("data")) {
+            MotionData parsedData = MotionData.decode(data.split(" ")[1]);
+            if (parsedData != null) {
+                this.motionData.add(parsedData);
+            }
+            // Otherwise check if it starts with 'calibrate', this is the ZERO point.
+        } else if ( data.startsWith("calibrate")) { // message to calibrate device
+            String[] vectorData = data.split(" ")[1].split(DELIMITER);
+            ZERO = new Vector3(
+                    Float.parseFloat(vectorData[0]),
+                    Float.parseFloat(vectorData[1]),
+                    Float.parseFloat(vectorData[2])
+            );
+            Log.i("MotionProcessor", "Device calibrated at " + ZERO.toString());
+        } else if ( data.startsWith("sampleRate")) {
+            this.sampleRate = Integer.parseInt(data.split(" ")[1]);
+        }
+    }
+
+    /**
+     * Function for calculating the path of the device.
+     * This only works when the ZERO point has been provided.
+     */
+    private void calculatePath() {
+
+        int offset = Math.max(0, motionData.size() - MAX_PATH_LENGTH);
+        Vector3 previous = ZERO.copy();
+
+        for (int i = offset; i < motionData.size(); i++) {
+            MotionData data = motionData.get(i);
+
+            // Get relative vector from the ZERO point
+            Vector3 relativePosition = data.acceleration
+                    .rotate(data.rotation.negate()) // Rotate acceleration vector with it's angle to get the acceleration relative to the vector of gravity
+                    .map((vector) ->  vector.) // Convert acceleration to relative spatial change
+
+            relativePath[i - offset]
+        }
+    }
+
 }
diff --git a/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/Vector3.java b/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/Vector3.java
new file mode 100644
index 0000000..a862af8
--- /dev/null
+++ b/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/processing/Vector3.java
@@ -0,0 +1,165 @@
+package com.example.fitbot.util.processing;
+
+public class Vector3 {
+
+    public double x, y, z;
+
+    /**
+     * Constructor for creating a new vector.
+     *
+     * @param x The X component of the vector.
+     * @param y The Y component of the vector.
+     * @param z The Z component of the vector.
+     */
+    public Vector3(double x, double y, double z) {
+        this.x = x;
+        this.y = y;
+        this.z = z;
+    }
+
+    /**
+     * Copy the vector.
+     *
+     * @return A new vector with the same values.
+     */
+    public Vector3 copy() {
+        return new Vector3(this.x, this.y, this.z);
+    }
+
+    /**
+     * Subtract the vector from another vector.
+     *
+     * @param other The other vector to subtract.
+     * @return The new vector.
+     */
+    public Vector3 subtract(Vector3 other) {
+        return new Vector3(this.x - other.x, this.y - other.y, this.z - other.z);
+    }
+
+    /**
+     * Add the vector to another vector.
+     *
+     * @param other The other vector to add.
+     * @return The new vector.
+     */
+    public Vector3 add(Vector3 other) {
+        return new Vector3(this.x + other.x, this.y + other.y, this.z + other.z);
+    }
+
+    /**
+     * Multiply the vector by a scalar.
+     *
+     * @param scalar The scalar to multiply by.
+     * @return The multiplied vector.
+     */
+    public Vector3 multiply(double scalar) {
+        return new Vector3(this.x * scalar, this.y * scalar, this.z * scalar);
+    }
+
+    /**
+     * Divide the vector by a scalar.
+     *
+     * @param scalar The scalar to divide by.
+     * @return The divided vector.
+     */
+    public Vector3 divide(double scalar) {
+        if (scalar == 0) throw new IllegalArgumentException("Cannot divide by zero.");
+        return new Vector3(this.x / scalar, this.y / scalar, this.z / scalar);
+    }
+
+    /**
+     * Negate the vector.
+     *
+     * @return The negated vector.
+     */
+    public Vector3 negate() {
+        return new Vector3(-this.x, -this.y, -this.z);
+    }
+
+    /**
+     * Rotate the vector around the X, Y, and Z axes.
+     *
+     * @param radX Rotation around the X axis in radians.
+     * @param radY Rotation around the Y axis in radians.
+     * @param radZ Rotation around the Z axis in radians.
+     * @return The rotated vector.
+     */
+    public Vector3 rotate(double radX, double radY, double radZ) {
+        double cosX = Math.cos(radX);
+        double cosY = Math.cos(radY);
+        double cosZ = Math.cos(radZ);
+        double sinX = Math.sin(radX);
+        double sinY = Math.sin(radY);
+        double sinZ = Math.sin(radZ);
+        double newX = x * cosY * cosZ + y * cosY * sinZ - z * sinY;
+        double newY = x * (sinX * sinY * cosZ - cosX * sinZ) + y * (sinX * sinY * sinZ + cosX * cosZ) + z * sinX * cosY;
+        double newZ = x * (cosX * sinY * cosZ + sinX * sinZ) + y * (cosX * sinY * sinZ - sinX * cosZ) + z * cosX * cosY;
+        return new Vector3(newX, newY, newZ);
+    }
+
+    /**
+     * Rotate the vector around the X, Y, and Z axes.
+     *
+     * @param rotation The rotation vector.
+     * @return The rotated vector.
+     */
+    public Vector3 rotate(Vector3 rotation) {
+        return rotate(rotation.x, rotation.y, rotation.z);
+    }
+
+    /**
+     * Rotate the vector around the X axis.
+     *
+     * @param angle Rotation around the X axis in radians.
+     * @return The rotated vector.
+     */
+    public Vector3 rotateX(double angle) {
+        double sinTheta = Math.sin(angle);
+        double cosTheta = Math.cos(angle);
+        return new Vector3(
+                x,
+                y * cosTheta - z * sinTheta,
+                y * sinTheta + z * cosTheta
+        );
+    }
+
+    /**
+     * Rotate the vector around the Y axis.
+     *
+     * @param angle Rotation around the Y axis in radians.
+     * @return The rotated vector.
+     */
+    public Vector3 rotateY(double angle) {
+        double sinTheta = Math.sin(angle);
+        double cosTheta = Math.cos(angle);
+        return new Vector3(
+                x * cosTheta + z * sinTheta,
+                y,
+                -x * sinTheta + z * cosTheta
+        );
+    }
+
+    /**
+     * Rotate the vector around the Z axis.
+     *
+     * @param angle Rotation around the Z axis in radians.
+     * @return The rotated vector.
+     */
+    public Vector3 rotateZ(double angle) {
+        double sinTheta = Math.sin(angle);
+        double cosTheta = Math.cos(angle);
+        return new Vector3(
+                x * cosTheta - y * sinTheta,
+                x * sinTheta + y * cosTheta,
+                z
+        );
+    }
+
+    public Vector3 map(VectorMapFunction function) {
+        return function.apply(this);
+    }
+
+    public interface VectorMapFunction {
+        Vector3 apply(Vector3 vector);
+    }
+}
diff --git a/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/IWebSocketHandler.java b/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/IWebSocketHandler.java
index db4a5f9..fa4cc98 100644
--- a/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/IWebSocketHandler.java
+++ b/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/IWebSocketHandler.java
@@ -9,7 +9,10 @@ public interface IWebSocketHandler {
 
     // Function for handling the connection of the WebSocket.
     default void onConnected(Socket socket) {}
+
     default void onDisconnected(Socket socket) {}
-    default void onMessageReceived(String message) {}
+
+    default void onMessageReceived(WebSocket.Message message, WebSocket.MessageReply replier) {}
+
     default void onError(Socket socket, String error) {}
 }
diff --git a/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocket.java b/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocket.java
index f528fab..e48e1f0 100644
--- a/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocket.java
+++ b/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocket.java
@@ -48,6 +48,19 @@ public class WebSocket {
         this.connectionHandler.listen();
     }
 
+    /**
+     * Method for setting the event handler for this WebSocket server.
+     * @param handler The handler to use. This handler will parse all events
+     *                that occur in this WebSocket connection. The events are the followed:
+     *                - onMessageReceived(Socket, String)
+     *                - onConnected(Socket)
+     *                - onDisconnected(Socket)
+     *                - onError(Socket, String)
+     */
+    public void setEventHandler(IWebSocketHandler handler) {
+        this.eventHandler = handler;
+    }
+
     /**
      * Method for getting the ServerSocket connection
      * @return The ServerSocket connection.
@@ -63,4 +76,61 @@ public class WebSocket {
     public boolean isConnected() {
         return !this.serverSocket.isClosed();
     }
+
+    /**
+     * Class representing a message received from a WebSocket connection.
+     */
+    public static class Message {
+
+        // Enumerable representing message type (opcode).
+        public enum Type {
+
+            CONTINUING((byte) 0x0),
+            TEXT((byte) 0x1),
+            BINARY((byte) 0x2),
+            RES0((byte) 0x3), RES1((byte) 0x4), RES2((byte) 0x5), RES3((byte) 0x6), RES4((byte) 0x7),
+            CLOSE_CONNECTION((byte) 0x8),
+            PING((byte) 0x9),
+            PONG((byte) 0xA),
+            RES5((byte) 0xB), RES6((byte) 0xC), RES7((byte) 0xD), RES8((byte) 0xE), RES9((byte) 0xF);
+            
+            byte opcode;
+            Type(final byte opcode) {
+                this.opcode = opcode;
+            }
+
+            /**
+             * Method for decoding the opcode of a message.
+             * @param opcode The opcode to decode.
+             * @return The message type.
+             */
+            public Type decode(byte opcode) {
+                return Type.values()[opcode & 0xF];
+            }
+            // Returns the opcode of this message type.
+            public byte getOpcode() { return this.opcode; }
+        }
+
+        public String message;
+        public WebSocketConnection connection;
+
+        /**
+         * Constructor for a WebSocket message.
+         * @param message The message that was sent
+         * @param connection The connection where the message came from.
+         */
+        public Message(WebSocketConnection connection, String message) {
+            this.message = message;
+            this.connection = connection;
+        }
+    }
+
+    /**
+     * Interface for a message reply.
+     * This can be used for when a message has been received from a client
+     * to reply back to the client.
+     */
+    public interface MessageReply {
+        void reply(String message);
+    }
 }
diff --git a/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocketConnection.java b/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocketConnection.java
new file mode 100644
index 0000000..60e0ae1
--- /dev/null
+++ b/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocketConnection.java
@@ -0,0 +1,35 @@
+package com.example.fitbot.util.server;
+
+import java.net.Socket;
+
+public class WebSocketConnection {
+
+    private final WebSocket origin;
+    private final Socket socket;
+
+    /**
+     * Constructor for creating an arbitrary WebSocket connection (Client)
+     * @param connection The server connection
+     * @param socket The client socket
+     */
+    public WebSocketConnection(WebSocket connection, Socket socket) {
+        this.origin = connection;
+        this.socket = socket;
+    }
+
+    /**
+     * Getter method for retrieving the WebSocket connection
+     * @return The WebSocket instance.
+     */
+    public WebSocket getOrigin() {
+        return origin;
+    }
+
+    /**
+     * Getter method for retrieving the Client Socket connection.
+     * @return The Socket connection.
+     */
+    public Socket getSocket() {
+        return socket;
+    }
+}
diff --git a/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocketConnectionHandler.java b/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocketConnectionHandler.java
index 4550f31..4018ce4 100644
--- a/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocketConnectionHandler.java
+++ b/code/src/Fitbot/app/src/main/java/com/example/fitbot/util/server/WebSocketConnectionHandler.java
@@ -5,6 +5,8 @@ import android.support.annotation.RequiresApi;
 import android.util.Log;
 
 import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
 import java.net.Socket;
 import java.nio.charset.StandardCharsets;
 import java.security.MessageDigest;
@@ -22,6 +24,7 @@ public class WebSocketConnectionHandler implements Runnable {
     /**
      * Constructor for WebSocketConnectionHandler.
      * This class handles all new incoming Socket connections.
+     *
      * @param webSocket The socket to check for new connections.
      */
     protected WebSocketConnectionHandler(WebSocket webSocket) {
@@ -31,37 +34,22 @@ public class WebSocketConnectionHandler implements Runnable {
     @RequiresApi(api = Build.VERSION_CODES.O)
     @Override
     public void run() {
+        // Listen for new connections until the socket
+        // closes.
         while (theSocket.isConnected()) {
             try {
+                // Find a new connection
                 Socket newSocket = this.theSocket.getSocket().accept();
                 this.theSocket.eventHandler.onConnected(newSocket);
 
-                Scanner scanner = new Scanner(newSocket.getInputStream(), "UTF-8");
-                String data = scanner.useDelimiter("\\r\\n\\r\\n").next();
-                Matcher header = Pattern.compile("^GET").matcher(data);
-
-                // Check if the header contains the GET keyword
-                // If this is the case, upgrade the HTTP connection to WebSocket.
-                if (header.find()) {
-                    Matcher match = Pattern.compile("Sec-WebSocket-Key: (.*)").matcher(data);
-                    match.find();
-
-                    String SECAccept = Base64.getEncoder().encodeToString(
-                            MessageDigest.getInstance("SHA-1").digest((match.group(1) + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11").getBytes(StandardCharsets.UTF_8)));
-
-                    byte[] response = (
-                            "HTTP/1.1 101 Switching Protocols\r\n" +
-                            "Connection: Upgrade\r\n" +
-                            "Upgrade: websocket\r\n" +
-                            "Sec-WebSocket-Accept: " +
-                            SECAccept + "\r\n\r\n").getBytes(StandardCharsets.UTF_8);
-                    newSocket.getOutputStream().write(response, 0, response.length);
-
-                    // TODO: Read data from socket and provide in onMessageReceived.
+                InputStream streamIn = newSocket.getInputStream();
+                OutputStream streamOut = newSocket.getOutputStream();
 
+                // Check if the connection was successfully upgraded to WebSocket
+                if (upgradeConnection(streamIn, streamOut)) {
+                    applyMessageDecoder(streamIn);
                 }
-
-            } catch (IOException | NoSuchAlgorithmException error) {
+            } catch (IOException  error) {
                 String reason = error.getMessage() == null ? "Unknown reason" : error.getMessage();
                 Log.e("WebSocketConnectionHandler", "Error listening to Socket connections: " + reason);
                 break;
@@ -69,9 +57,121 @@ public class WebSocketConnectionHandler implements Runnable {
         }
     }
 
+    /**
+     * Method for upgrading a HTTP connection to a WebSocket connection.
+     * This checks whether the client sent a GET header and sends back
+     * the required headers to upgrade the connection.
+     * @param streamIn  The InputStream of the client socket connection.
+     * @param streamOut The OutputStream of the client socket connection.
+     * @return Whether or not the connection was successfully upgraded.
+     */
+    @RequiresApi(api = Build.VERSION_CODES.O)
+    private boolean upgradeConnection(InputStream streamIn, OutputStream streamOut) {
+        Scanner scanner = new Scanner(streamIn, "UTF-8");
+        String data = scanner.useDelimiter("\\r\\n\\r\\n").next();
+        Matcher header = Pattern.compile("^GET").matcher(data);
+
+        // Check if the header contains the GET keyword
+        // If this is the case, upgrade the HTTP connection to WebSocket.
+        if (!header.find())
+            return false;
+
+        Matcher match = Pattern.compile("Sec-WebSocket-Key: (.*)").matcher(data);
+        match.find(); // Get next match
+
+        try {
+            String SECAccept = Base64.getEncoder().encodeToString(
+                    MessageDigest.getInstance("SHA-1").digest((match.group(1) + "258EAFA5-E914-47DA-95CA-C5AB0DC85B11").getBytes(StandardCharsets.UTF_8)));
+
+            byte[] response = (
+                            "HTTP/1.1 101 Switching Protocols\r\n" +
+                            "Connection: Upgrade\r\n" +
+                            "Upgrade: websocket\r\n" +
+                            "Sec-WebSocket-Accept: " +
+                            SECAccept + "\r\n\r\n").getBytes(StandardCharsets.UTF_8);
+            streamOut.write(response, 0, response.length);
+
+        } catch (IOException | NoSuchAlgorithmException error) {
+            Log.e("WebSocketConnectionHandler", "Failed upgrading HTTP to WebSocket connection" + error.getMessage());
+            return false;
+        }
+        return true;
+    }
+
+    /**
+     * Method for applying a message decoder for whenever a socket receives data.
+     * This method attemps to decode a message received from a WebSocket connection.
+     * This message is in the
+     * @param streamIn The message stream to decode.
+     */
+    private void applyMessageDecoder(InputStream streamIn) {
+
+    }
+
+    /**
+     * Method for decoding an encoded WebSocket message
+     * @param bytes The message to decode, in UTF-8 format.
+     * @return The decoded message.
+     * @throws IllegalArgumentException When the `frame` content is in an incorrect format.
+     */
+    public static String decodeWebSocketMessage(byte[] bytes) {
+        // Check if the packet isn't corrupted
+        if (bytes.length <= 2 || (bytes[0] & 0b1110) != 0)
+            throw new IllegalArgumentException("Attempted to decode corrupted WebSocket frame data");
+
+        byte opcode        = (byte) (bytes[0] & 0b11110000); // Opcode (4 bits)
+        byte payloadLength = (byte) (bytes[1] & 0b01111111); // Payload size (7 bits)
+        boolean fin        = (bytes[0] & 0b1) != 0; // Whether this is the whole message
+        boolean masked     = (bytes[1] & 0b10000000) != 0; // Whether the 9th bit is masked
+
+        System.out.printf("Fin: %b, Opcode: %d, masked: %b\n", fin, opcode, masked);
+
+        long extendedPayloadLength = 0;
+        int byteOffset = 2;
+
+        // Check whether the payload length is 16-bit
+        if (payloadLength == 126) {
+            // 16-bit extended payload length (byte 2 and 3)
+            extendedPayloadLength = ((bytes[2] & 0xFF) << 8) | (bytes[3] & 0xFF);
+            byteOffset += 2;
+
+            // Check whether payload length is 64-bit
+        } else if (payloadLength == 127) {
+            // 64-bit extended payload length
+            for (int i = 0; i < 8; i++)
+                extendedPayloadLength |= (long) (bytes[2 + i] & 0xFF) << ((7 - i) * 8);
+            byteOffset += 8;
+
+        } else {
+            extendedPayloadLength = payloadLength;
+        }
+
+        byte[] maskingKey = null;
+        byte[] payloadData = new byte[(int) extendedPayloadLength];
+
+
+        // Check if the MASK bit was set, if so, copy the key to the `maskingKey` array.
+        if (masked) {
+            maskingKey = new byte[4];
+            System.arraycopy(bytes, byteOffset, maskingKey, 0, 4); // move mask bytes
+            byteOffset += 4;
+        }
+
+        // Copy payload bytes into `payloadData` array.
+        System.arraycopy(bytes, byteOffset, payloadData, 0, payloadData.length);
+
+        // If mask is present, decode the payload data with the mask.
+        if (masked)
+            for (int i = 0; i < payloadData.length; i++)
+                payloadData[i] ^= maskingKey[i % 4];
+
+        // Convert payload data to string
+        return new String(payloadData, StandardCharsets.UTF_8);
+    }
+
     /**
      * Method for checking whether the connection handler is actively listening.
-     * @return Whether or not it's listening.
+     * @return Whether it's listening.
      */
     public boolean isActive() {
         return this.thread.isAlive();
diff --git a/code/src/Fitbot/app/src/test/java/com/example/fitbot/WebSocketMessageParsingTest.java b/code/src/Fitbot/app/src/test/java/com/example/fitbot/WebSocketMessageParsingTest.java
new file mode 100644
index 0000000..3dd4107
--- /dev/null
+++ b/code/src/Fitbot/app/src/test/java/com/example/fitbot/WebSocketMessageParsingTest.java
@@ -0,0 +1,37 @@
+package com.example.fitbot;
+
+
+import com.example.fitbot.util.server.WebSocketConnectionHandler;
+
+import org.junit.Test;
+
+/**
+ * Created on 07/05/2024 at 18:27
+ * by Luca Warmenhoven.
+ */
+public class WebSocketMessageParsingTest {
+
+    @Test
+    public void parseWebSocketMessage() {
+
+        String reference = "abcdef";
+        final byte[] encoded = {
+                (byte) 129, (byte) 134, (byte) 167,
+                (byte) 225, (byte) 225, (byte) 210,
+                (byte) 198, (byte) 131, (byte) 130,
+                (byte) 182, (byte) 194, (byte) 135
+        };
+        String decoded = "";
+        try {
+            decoded = WebSocketConnectionHandler.decodeWebSocketMessage(encoded);
+        } catch (Exception e) {
+            System.err.println("Error occurred whilst attempting to parse input" + e.getMessage());
+        }
+        System.out.println("Parsed output: '" + decoded + "'");
+        if (decoded.equals(reference)) {
+            System.out.println("Test passed");
+        } else {
+            System.out.println("Test failed");
+        }
+    }
+}
diff --git a/docs/personalDocs/Luca/literatuuronderzoek/onderzoek.md b/docs/personalDocs/Luca/literatuuronderzoek/onderzoek.md
index cbd709b..2c945f4 100644
--- a/docs/personalDocs/Luca/literatuuronderzoek/onderzoek.md
+++ b/docs/personalDocs/Luca/literatuuronderzoek/onderzoek.md
@@ -1,3 +1,25 @@
+## Hoe kan technologie worden ingezet om cognitieve achteruitgang tegen te gaan?
+
+
+### Welke oorzaken zijn er voor cognitieve achteruitgang?
+
+### Wat voor methodes zijn er om cognitieve achteruitgang te remmen?
+
+### Hoe kan techniek worden toegepast om 
+
+
+
+
+
+
+Inleiding: ~10% 
+Conclusie: ~10% 
+~300 woorden totaal
+
+Minimaal 5 bronnen zoeken 
+
+
+
 ## Hoe kunnen ethische richtlijnen worden ontwikkeld voor het toepassen van kunstmatige intelligentie bij het aanpakken van eenzaamheid onder ouderen?
 
 ---