.github/workflows/test.yml

@@ -0,0 +1,26 @@
+name: Run Tests
+
+on:
+  push:
+    branches: ["main"]
+  workflow_dispatch:
+  pull_request:
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set up Node.js
+        uses: actions/setup-node@v2
+        with:
+          node-version: '20'
+
+      - name: Install dependencies
+        run: npm install
+
+      - name: Run tests
+        run: npm run test:ci

.gitignore

@@ -890,3 +890,5 @@ next-env.d.ts
 
 # Writerside
 /Writerside
+
+package-lock.json

__tests__/scripts.test.js

@@ -0,0 +1,21 @@
+import { render, screen, fireEvent, waitFor } from '@testing-library/react';
+import '@testing-library/jest-dom';
+import Home from "../src/app/page";
+
+jest.mock('../src/app/scripts', () => ({
+    customLog: jest.fn(),
+    customLogClear: jest.fn(),
+}));
+
+jest.mock('../src/solver/glpk.min.js', () => ({
+    LPF_ECOND: 2,
+}));
+
+test('render home page', () => {
+    // render website
+    render(<Home />);
+
+    // check if text is in document
+    const headingElement = screen.getByText(/OR-Tool/i);  // text search in document
+    expect(headingElement).toBeInTheDocument();
+});

jest.config.js

@@ -0,0 +1,15 @@
+const nextJest = require('next/jest');
+
+const createJestConfig = nextJest({
+  dir: './',
+});
+
+const customJestConfig = {
+  testEnvironment: 'jest-environment-jsdom',
+  moduleNameMapper: {
+    '^@/(.*)$': '<rootDir>/src/$1',
+  },
+  setupFilesAfterEnv: ['<rootDir>/jest.setup.js'],
+};
+
+module.exports = createJestConfig(customJestConfig);

jest.setup.js

@@ -0,0 +1 @@
+import '@testing-library/jest-dom';

package.json

@@ -6,22 +6,34 @@
     "dev": "next dev",
     "build": "next build",
     "start": "next start",
-    "lint": "next lint"
+    "lint": "next lint",
+    "test": "jest --watchAll",
+    "test:ci": "jest --ci --coverage"
   },
   "dependencies": {
     "glpk.js": "^4.0.2",
+    "i18n": "^0.15.1",
+    "i18next": "^23.15.2",
+    "i18next-browser-languagedetector": "^8.0.0",
+    "jest-environment-jsdom": "^29.7.0",
     "next": "14.2.11",
+    "next-i18next": "^15.3.1",
     "react": "^18",
     "react-dom": "^18",
+    "react-i18next": "^15.0.2",
     "react-popup": "^0.11.2",
     "reactjs-popup": "^2.0.6"
   },
   "devDependencies": {
+    "@testing-library/jest-dom": "^6.5.0",
+    "@testing-library/react": "^16.0.1",
+    "@testing-library/user-event": "^14.5.2",
     "@types/node": "^20",
     "@types/react": "^18",
     "@types/react-dom": "^18",
     "eslint": "^8",
     "eslint-config-next": "14.2.11",
+    "jest": "^29.7.0",
     "postcss": "^8",
     "tailwindcss": "^3.4.1",
     "typescript": "^5"

src/app/globals.css

@@ -3,8 +3,8 @@
 @tailwind utilities;
 
 :root {
-  --background: #ffffff;
+  --background: #171717;
-  --foreground: #171717;
+  --foreground: #ffffff;
 }
 
 @media (prefers-color-scheme: dark) {
@@ -157,4 +157,28 @@ body {
 
 .popup-overlay {
   background: rgba(0, 0, 0, 0.5);
-}
+}
+
+.dropdown-custom {
+  width: 20%;
+  background-color: black;
+  color: white;
+  border: none;
+  padding: 10px;
+  font-size: 16px;
+  cursor: pointer;
+}
+
+.dropdown-custom:hover {
+  background-color: #444;
+}
+
+.dropdown-custom-maxmin {
+  width: 150px;
+  background-color: black;
+  color: white;
+  border: none;
+  padding: 10px;
+  font-size: 16px;
+  cursor: pointer;
+}

src/app/lang.ts

@@ -0,0 +1,204 @@
+export default function text(lang: string, input: string): string {
+    // German translation
+    if (lang === "ger") {
+        switch (input) {
+            case "header_title":
+                return "OR-Tool";
+                case "header_subtitle":
+                    return "von Spaceholder Programming";
+                case "boxObjTitle":
+                    return "Ziel";
+                case "boxObjDesc":
+                    return "Geben Sie Ihr Ziel hier ein. Es ist nur ein Ziel erlaubt. Verwenden Sie eine Zeile dafür (kein 'Enter'!). Erlaubte Symbole sind 0-9, a-z, A-Z und <>=.\nBeispiel:\nx + y\n-786433 x1 + 655361 x2";
+                case "boxSubjTitle":
+                    return "Nebenbedingungen";
+                case "boxSubjDesc":
+                    return "Geben Sie Ihre Nebenbedingungen hier ein. Eine pro Zeile (mit der 'Enter'-Taste trennen). Erlaubte Symbole sind 0-9, a-z, A-Z und <>=.\nBeispiel:\n+1 x + 2 y <= 15\n524321 x14 + 524305 x15 <= 4194303.5";
+                case "boxBoundsTitle":
+                    return "Grenzen";
+                case "boxBoundsDesc":
+                    return "Geben Sie Ihre Grenzen hier ein. Eine pro Zeile (mit der 'Enter'-Taste trennen). Erlaubte Symbole sind 0-9, a-z, A-Z und <>=.\nBeispiel:\nx >= 0\nx > 0\n0 <= x1 <= 1";
+                case "boxVarsTitle":
+                    return "Variablen";
+                case "boxVarsDesc":
+                    return "Listen Sie alle Ihre Variablen auf. Eine pro Zeile (mit der 'Enter'-Taste trennen). Erlaubte Symbole sind a-z, A-Z.\nBeispiel:\nx\ny";
+                case "boxExportLP":
+                    return "Als LP exportieren";
+                case "boxOut":
+                    return "Geben Sie ein Problem ein und drücken Sie eine Aktionstaste, um die Ausgabe anzuzeigen...";
+                case "buttonCalc":
+                    return "Berechnen";
+                case "etime":
+                    return "Berechnungsdauer";
+                case "seconds":
+                    return "Sekunden";
+                case "err_invalidInput":
+                    return "Fehler: Ungültige Eingabe in";
+                case "err_nullInput":
+                    return "Fehler: NULL- oder undefinierte Eingabe in";
+                case "err_invalidInput":
+                    return "Fehler: Ungültige Eingabe oder fehlendes Zeichen in";
+                case "input_checks_successful":
+                    return "Alle Eingabeprüfungen erfolgreich.";
+                case "input_checks_start":
+                    return "Starte Eingabeprüfungen...";
+                case "obj_box":
+                    return "Zielfeld";
+                case "subj_box":
+                    return "Bedingungsfeld";
+                case "bounds_box":
+                    return "Grenzenfeld";
+                case "vars_box":
+                    return "Variablenfeld";
+                case "err_emptyBox":
+                    return "Fehler: Leeres Textfeld.";
+                case "calculating":
+                    return "Berechne...";
+                case "maximize":
+                    return "Maximieren";
+                case "minimize":
+                    return "Minimieren";
+                case "run_optimization":
+                    return "Optimierung mit Eingaben wird ausgeführt";
+                case "startProblemSetup":
+                    return "Starte Problemerstellung...";
+                case "succProblemSetup":
+                    return "Problem erstellt.";
+                case "startScaling":
+                    return "Skalieren des Problems...";
+                case "succScaling":
+                    return "Skalierung erfolgreich.";
+                case "startOptimizationSimplex":
+                    return "Starte Simplex-Optimierung...";
+                case "succOptimizationSimplex":
+                    return "Simplex-Optimierung abgeschlossen.";
+                case "startOptimizationInteger":
+                    return "Starte Ganzzahloptimierung...";
+                case "succOptimizationInteger":
+                    return "Ganzzahloptimierung abgeschlossen.";
+                case "finalObjValue":
+                    return "Endgültiger Zielfunktionswert";
+                case "varsValues":
+                    return "Wert jeder Variable";
+                case "dualValues":
+                    return "Dualwerte der Einschränkungen";
+                case "downloadPrepFileString":
+                    return "Dateiinhalt wird vorbereitet...";
+                case "downloadPrepFile":
+                    return "Datei wird vorbereitet...";
+                case "downloadStart":
+                    return "Download wird gestartet.";
+                case "downloadPrep":
+                    return "Download wird vorbereitet...";
+                case "downloadFetchInput":
+                    return "Eingaben werden geladen...";
+                case "importing":
+                    return "Importiere...";
+            default:
+                return input;
+        }
+        
+    }
+
+    // English translation
+    if (lang === "eng") {
+        switch (input) {
+            case "header_title":
+                return "OR-Tool";
+            case "header_subtitle":
+                return "by Spaceholder Programming";
+            case "boxObjTitle":
+                return "Objective";
+            case "boxObjDesc":
+                return "Insert your objective here. One objective is allowed. Use one line for it (no \"return\"!) Allowed symbols are 0-9, a-z, A-Z and <>=.\nExample:\nx + y\n-786433 x1 + 655361 x2";
+            case "boxSubjTitle":
+                return "Subject";
+            case "boxSubjDesc":
+                return "Insert your subject here. One per line (divide by 'return' button). Allowed symbols are 0-9, a-z, A-Z and <>=.\nExample:\n+1 x + 2 y <= 15\n524321 x14 + 524305 x15 <= 4194303.5";
+            case "boxBoundsTitle":
+                return "Bounds";
+            case "boxBoundsDesc":
+                return "Insert your bounds here. One per line (divide by 'return' button). Allowed symbols are 0-9, a-z, A-Z and <>=.\nExample:\nx >= 0\nx > 0\n0 <= x1 <= 1";
+            case "boxVarsTitle":
+                return "Variables";
+            case "boxVarsDesc":
+                return "List all your variables. One per line (divide by 'return' button). Allowed symbols are a-z, A-Z.\nExample:\nx\ny";
+            case "boxExportLP":
+                return "Export as LP";
+            case "boxOut":
+                return "Input a problem and an action button to display output...";
+            case "buttonCalc":
+                return "Calculate";
+            case "etime":
+                return "Elapsed time";
+            case "seconds":
+                return "seconds";
+            case "err_invalidInput":
+                return "Error: Invalid input in";
+            case "err_nullInput":
+                return "Error: NULL or undefined input in";
+            case "err_invalidInput":
+                return "Error: Invalid input or missing character in";
+            case "input_checks_successful":
+                return "All input checks successful."
+            case "input_checks_start":
+                return "Starting input checks...";
+            case "obj_box":
+                return "object box";
+            case "subj_box":
+                return "subject box";
+            case "bounds_box":
+                return "bounds box";
+            case "vars_box":
+                return "variables box";
+            case "err_emptyBox":
+                return "Error: Empty text box.";
+            case "calculating":
+                return "Calculating...";
+            case "maximize":
+                return "Maximize";
+            case "minimize":
+                return "Minimize";
+            case "run_optimization":
+                return "Running optimization with input";
+            case "startProblemSetup":
+                return "Starting problem setup...";
+            case "succProblemSetup":
+                return "Problem created.";
+            case "startScaling":
+                return "Scaling problem...";
+            case "succScaling":
+                return "Scaling successful.";
+            case "startOptimizationSimplex":
+                return "Starting simplex optimization...";
+            case "succOptimizationSimplex":
+                return "Simplex optimization complete.";
+            case "startOptimizationInteger":
+                return "Starting integer optimization...";
+            case "succOptimizationInteger":
+                return "Integer optimization complete.";
+            case "finalObjValue":
+                return "Final objective value";
+            case "varsValues":
+                return "Value of each variable";
+            case "dualValues":
+                return "Dual values of constraints";
+            case "downloadPrepFileString":
+                return "Preparing file content string...";
+            case "downloadPrepFile":
+                return "Preparing file...";
+            case "downloadStart":
+                return "Starting download.";
+            case "downloadPrep":
+                return "Preparing download...";
+            case "downloadFetchInput":
+                return "Fetching input...";
+            case "importing":
+                return "Importing...";
+            default:
+                return input;
+        }
+    }
+
+    return "Error: Translation Module - Language Not Known.";
+}

src/app/layout.tsx

@@ -45,7 +45,7 @@ export default function RootLayout({
                 width={16}
                 height={16}
               />
-              Go to our docs
+              Docs
             </a>
             <a
               className="flex items-center gap-2 hover:underline hover:underline-offset-4"
@@ -60,7 +60,7 @@ export default function RootLayout({
                 width={16}
                 height={16}
               />
-              See the source code
+              Source Code
             </a>
             <a
               className="flex items-center gap-2 hover:underline hover:underline-offset-4"
@@ -75,7 +75,7 @@ export default function RootLayout({
                 width={16}
                 height={16}
               />
-              Powered by GLPK
+              GLPK
             </a>
           </footer>
         </div>

src/app/page.tsx

@@ -1,58 +1,95 @@
 'use client'
 
+import React, { useState } from 'react';
 import { Box, Button, Output } from "./modules";
-import { calculate_click, downloadLP, import_click } from "./scripts"
+import { calculate_click, downloadLP, import_click } from "./scripts";
+import text from "./lang";
 
 export default function Home() {
+  const [language, setLanguage] = useState('eng');
+  const [maxminOption, setMaxminOption] = useState('maximize'); // Zustand für den MaxMin-Switch
+
+  const tr_hTitle = text(language, 'header_title');
+  const tr_hSubtitle = text(language, 'header_subtitle');
+  const tr_boxObjTitle = text(language, 'boxObjTitle');
+  const tr_boxObjDesc = text(language, "boxObjDesc");
+  const tr_boxSubjTitle = text(language, 'boxSubjTitle');
+  const tr_boxSubjDesc = text(language, "boxSubjDesc");
+  const tr_boxBoundsTitle = text(language, 'boxBoundsTitle');
+  const tr_boxBoundsDesc = text(language, "boxBoundsDesc");
+  const tr_boxVarsTitle = text(language, 'boxVarsTitle');
+  const tr_boxVarsDesc = text(language, "boxVarsDesc");
+  const tr_boxOut = text(language, "boxOut");
+  const tr_boxExportLP = text(language, "boxExportLP");
+  const tr_calc_max = text(language, "maximize");
+  const tr_calc_min = text(language, "minimize");
+  const tr_calcButton = text(language, "buttonCalc");
+
+  const handleLanguageChange = (event: React.ChangeEvent<HTMLSelectElement>) => {
+    setLanguage(event.target.value);
+  };
+
+  const handleMaxMinChange = (event: React.ChangeEvent<HTMLSelectElement>) => {
+    setMaxminOption(event.target.value); // Update den Zustand basierend auf dem Wert des Selects
+  };
+
   return (
     <>
       <header className="header">
         <div className="title">
           <main className="header_box">
-            Operations Research Tool
+            {tr_hTitle}
-            <br></br>
+            <br />
             <span className="header_copyright">
-              <i>by Spaceholder Programming</i>
+              <i>{tr_hSubtitle}</i>
             </span>
+            <br />
+            <select id="language_current" value={language} onChange={handleLanguageChange} className="dropdown-custom">
+              <option value="ger">Deutsch</option>
+              <option value="eng">English</option>
+            </select>
           </main>
         </div>
       </header>
       <Box
-        title={"Objective"}
+        title={tr_boxObjTitle}
-        placeholder={"Insert your objective here. One objective is allowed. Use one line for it (no \"return\"!) Allowed symbols are 0-9, a-z, A-Z and <>=.\nExample:\nx + y\n-786433 x1 + 655361 x2"}
+        placeholder={tr_boxObjDesc}
-        id="objective"/>
+        id="objective"
+      />
       <Box
-        title={"Subject"}
+        title={tr_boxSubjTitle}
-        placeholder={"Insert your subject here. One per line (divide by 'return' button). Allowed symbols are 0-9, a-z, A-Z and <>=.\nExample:\n+1 x + 2 y <= 15\n524321 x14 + 524305 x15 <= 4194303.5"}
+        placeholder={tr_boxSubjDesc}
-        id="subject"/>
+        id="subject"
+      />
       <Box
-        title={"Bounds"}
+        title={tr_boxBoundsTitle}
-        placeholder={"Insert your bounds here. One per line (divide by 'return' button). Allowed symbols are 0-9, a-z, A-Z and <>=.\nExample:\nx >= 0\nx > 0\n0 <= x1 <= 1"}
+        placeholder={tr_boxBoundsDesc}
-        id="bounds"/>
+        id="bounds"
+      />
       <Box
-        title={"Variables"}
+        title={tr_boxVarsTitle}
-        placeholder={"List all your variables. One per line (divide by 'return' button). Allowed symbols are a-z, A-Z.\nExample:\nx\ny"}
+        placeholder={tr_boxVarsDesc}
-        id="vars" />
+        id="vars"
+      />
+      <select id="maxminswitch" value={maxminOption} onChange={handleMaxMinChange} className="dropdown-custom-maxmin">
+        <option value="maximize">{tr_calc_max}</option>
+        <option value="minimize">{tr_calc_min}</option>
+      </select>
       <Button
-        title={"Calculate"}
+        title={tr_calcButton}
         className={"button_green"}
-        onClickFunc={calculate_click} />
+        onClickFunc={calculate_click}
-      {/* <Popup_Button
+      />
-        title={"Import"}
-        className={"button"} /> */}
       <Button
-        title={"Export as LP"}
+        title={tr_boxExportLP}
         className={"button"}
-        onClickFunc={downloadLP} />
+        onClickFunc={downloadLP}
-      <br></br>
+      />
+      <br />
       <Output
         id="out"
-        text={"Input a problem and an action button to display output..."}/>
+        text={tr_boxOut}
-      {/* <Popup_Button
+      />
-        title="Popup"
-        className="button"
-        /> */}
-
     </>
   );
 }

src/app/scripts.ts

@@ -5,26 +5,41 @@ import * as LPAPI from "../api/optimizeLP.js"
 import * as GLPKAPI from "../solver/glpk.min.js"
 import { start } from "repl";
 
+import text from "./lang"
+
 // custom log so we can append the output dynamically
-function customLog(message: string) {
+export function customLog(input: string) {
-  console.log(message); // Continue to print message inside of box
+  // get language
+  const lang = (document.getElementById('language_current') as HTMLSelectElement)?.value;
 
   // Get Output Box
   const outputElement = document.getElementById('out');
 
+  // load text
+  const message: string = text(lang, input);
+  console.log(message); // Continue to print message inside of box
+
   // Append message if element exists
   if (outputElement) {
     outputElement.innerHTML += message + "<br>"; // Append message
   }
 }
 
-function customLogClear() {
+export function customLogClear() {
   const outElement = document.getElementById('out');
   if (outElement) {
     outElement.innerHTML = "";
   }
 }
 
+export function getTranslation(input: string) {
+  // get language
+  const lang = (document.getElementById('language_current') as HTMLSelectElement)?.value;
+
+  // return translation
+  return text(lang, input);
+}
+
 function walltimeStopAndPrint(startpoint: number) {
   // calculating elapsed time as timestamp
   let duration = Date.now() - startpoint;
@@ -37,7 +52,8 @@ function walltimeStopAndPrint(startpoint: number) {
   const durationFormatted = seconds + (milliseconds >= 0 ? "." : ".") + Math.abs(milliseconds).toFixed(3).slice(2);
 
   // Printing elapsed time
-  customLog("Elapsed time: " + durationFormatted + " seconds<br>");
+  customLog(getTranslation("etime") + ": " + durationFormatted + " " + getTranslation("seconds"));
+  customLog("");
 
   // return durationFormatted;
 }
@@ -47,11 +63,11 @@ function walltimeStart() {
 }
 
 function isInputValidRegex(obj: string | undefined, subj: string | undefined, bounds: string | undefined, vars: string | undefined): boolean {
-  customLog("Starting input checks...");
+  customLog("input_checks_start");
-  
+
   // standard case: input is undefined - invalid
-  if (obj === undefined || obj === null || subj === undefined || subj === null || bounds === undefined || bounds === null || vars === undefined || vars === null) { 
+  if (obj === undefined || obj === null || subj === undefined || subj === null || bounds === undefined || bounds === null || vars === undefined || vars === null) {
-    customLog("Error: Function isInputValidRegex received undefined or null input.");
+    customLog(getTranslation("err_nullInput") + "function isInputValidRegex.");
     return false;
   }
 
@@ -59,54 +75,54 @@ function isInputValidRegex(obj: string | undefined, subj: string | undefined, bo
   let regex = /^[ (\n)]*[\+-]? *((\d+(.\d+)? )?[a-zA-Z][a-zA-Z0-9]*)( *[\+-] *((\d+(.\d+)? )?[a-zA-Z][a-zA-Z0-9]*))*[ (\n)]*$/g;
   let isValid = regex.test(obj);
   if (!isValid) {
-    customLog("Error: Invalid or missing character in object box.");
+    customLog(getTranslation("err_invalidInput") + " " + getTranslation("obj_box") + ".");
-      return false;
+    return false;
   }
 
   // RegEx check for subject
   regex = /^([ (\n)]*[\+-]* *(\d+(.\d+)? )?[a-zA-Z][a-zA-Z0-9]*( *[\+-] *(\d+(.\d+)? )?[a-zA-Z][a-zA-Z0-9]*)* *((<=?)|(>=?)|=) *[\+-]? *\d+(.\d+)?[ (\n)]*)+$/g;
   isValid = regex.test(subj);
   if (!isValid) {
-    customLog("Error: Invalid or missing character in subject box.");
+    customLog(getTranslation("err_invalidInput") + " " + getTranslation("subj_box") + ".");
-      return false;
+    return false;
   }
 
-// RegEx check for subject
+  // RegEx check for subject
-regex = /[ (\n)]*(([a-zA-Z][a-zA-Z0-9]* *((<=?)|(>=?)|=) *\d(.\d+)?)|((\d(.\d+)?) *<=? *[a-zA-Z][a-zA-Z0-9]* *<= *(\d(.\d+)?)))[ (\n)]*/g;
+  regex = /[ (\n)]*(([a-zA-Z][a-zA-Z0-9]* *((<=?)|(>=?)|=) *\d(.\d+)?)|((\d(.\d+)?) *<=? *[a-zA-Z][a-zA-Z0-9]* *<= *(\d(.\d+)?)))[ (\n)]*/g;
-isValid = regex.test(bounds);
+  isValid = regex.test(bounds);
-if (!isValid) {
+  if (!isValid) {
-  customLog("Error: Invalid or missing character in bounds box.");
+    customLog(getTranslation("err_invalidInput") + " " + getTranslation("bounds_box") + ".");
     return false;
-}
+  }
 
   // RegEx check for variables
   regex = /^ *([a-zA-Z][a-zA-Z0-9]*(\n)* *)+$/g;
   isValid = regex.test(vars);
   if (!isValid) {
-    customLog("Error: Invalid or missing  character in variables box.");
+    customLog(getTranslation("err_invalidInput") + " " + getTranslation("vars_box") + ".");
     return false;
   }
 
-  customLog("All input checks successful.");
+  customLog("input_checks_successful");
   customLog("");
   return true;
 }
 
 function isInputFilled(obj: string | undefined, subj: string | undefined, bounds: string | undefined, vars: string | undefined) {
   if (obj == "" || obj == null || obj == undefined) {
-    customLog("Error: Empty input field.");
+    customLog("err_emptyBox");
     return false;
   }
   if (subj == "" || subj == null || subj == undefined) {
-    customLog("Error: Empty input field.");
+    customLog("err_emptyBox");
     return false;
   }
   if (bounds == "" || bounds == null || bounds == undefined) {
-    customLog("Error: Empty input field.");
+    customLog("err_emptyBox");
     return false;
   }
   if (vars == "" || vars == null || vars == undefined) {
-    customLog("Error: Empty input field.");
+    customLog("err_emptyBox");
     return false;
   }
   return true;
@@ -115,7 +131,8 @@ function isInputFilled(obj: string | undefined, subj: string | undefined, bounds
 export function calculate_click() {
   customLogClear();
   const timer = walltimeStart();
-  customLog("Calculating...<br>");
+  customLog("calculating");
+  customLog("");
 
   let objective: string | undefined;
   const objectiveElement = document.getElementById('objective');
@@ -190,77 +207,95 @@ export function calculate_click() {
 
   //   console.log(parseFunction(decider));
 
-  
+
   // catch error: empty input field(s)
   if (!isInputFilled(objective, subject, bounds, variables)) return;
 
   // catch error: variables field has invalid characters
   if (!isInputValidRegex(objective, subject, bounds, variables)) return;
 
-  let wholeText: string = "Maximize\n obj: " + objective
+  // fetch operator
-                        + "\nSubject To \n" + subject 
+  const maxmin = (document.getElementById('maxminswitch') as HTMLSelectElement)?.value;
-                        + "\nBounds \n" + bounds
+  let operator = "Minimize";
-                        + "\nGenerals \n" + variables
+  if (maxmin == "maximize") operator = "Maximize";
-                        + "\nEnd";
+
+  let wholeText: string = operator + "\n obj: " + objective
+    + "\nSubject To \n" + subject
+    + "\nBounds \n" + bounds
+    + "\nGenerals \n" + variables
+    + "\nEnd";
 
   // customLog("<br><br>DEBUGGING<br><br>\nfunctions:<br>" + functions + "<br><br>variables:<br>" + variables + "<br><br>DEBUGGING END<br>");
 
-  customLog("Running optimization with input: \"" + wholeText + "\"<br>");
+  customLog(getTranslation("run_optimization") + ": \"" + wholeText + "\"");
+  customLog("");
   run(wholeText);
 
   walltimeStopAndPrint(timer);
 }
 
 function run(text: string) {
-  customLog("Starting problem setup...");
+  customLog("startProblemSetup");
   let lp = GLPKAPI.glp_create_prob();
   GLPKAPI.glp_read_lp_from_string(lp, null, text);
-  customLog("Problem created.<br>");
+  customLog("succProblemSetup");
+  customLog("");
 
-  customLog("Scaling problem...");
+  customLog("startScaling");
   GLPKAPI.glp_scale_prob(lp, GLPKAPI.GLP_SF_AUTO);
-  customLog("Scaling complete.<br>");
+  customLog("succScaling");
+  customLog("");
 
-  customLog("Starting simplex optimization...");
+  customLog("startOptimizationSimplex");
   let smcp = new GLPKAPI.SMCP({ presolve: GLPKAPI.GLP_ON });
   GLPKAPI.glp_simplex(lp, smcp);
-  customLog("Simplex optimization complete.<br>");
+  customLog("succOptimizationSimplex");
+  customLog("");
 
-  customLog("Starting integer optimization...");
+  customLog("startOptimizationInteger");
   let iocp = new GLPKAPI.IOCP({ presolve: GLPKAPI.GLP_ON });
   GLPKAPI.glp_intopt(lp, iocp);
-  customLog("Integer optimization complete.<br>");
+  customLog("succOptimizationInteger");
+  customLog("");
 
   // customLog("obj: " + GLPKAPI.glp_mip_obj_val(lp));
-  customLog("<i>Final objective value: " + GLPKAPI.glp_mip_obj_val(lp) + "</i><br>");
+  customLog("<i>" + getTranslation("finalObjValue") + ": " + GLPKAPI.glp_mip_obj_val(lp) + "</i>");
-  customLog("Value of each variable:");
+  customLog("");
-  for (let i = 1; i <= GLPKAPI.glp_get_num_cols(lp) - 1; i++) {   // "-1" to remove the "End-variable" from logs
+  customLog(getTranslation("varsValues") + ":");
+  for (let i = 1; i <= GLPKAPI.glp_get_num_cols(lp); i++) {
     customLog(GLPKAPI.glp_get_col_name(lp, i) + " = " + GLPKAPI.glp_mip_col_val(lp, i));
   }
   customLog("");
 
-  customLog("Dual values of constraints:");
+  customLog(getTranslation("dualValues") + ":");
-    for (let j = 1; j <= GLPKAPI.glp_get_num_rows(lp); j++) {
+  for (let j = 1; j <= GLPKAPI.glp_get_num_rows(lp); j++) {
-        const dualValue = GLPKAPI.glp_get_row_dual(lp, j); // fetch dual
+    const dualValue = GLPKAPI.glp_get_row_dual(lp, j); // fetch dual
-        const constraintName = GLPKAPI.glp_get_row_name(lp, j);
+    const constraintName = GLPKAPI.glp_get_row_name(lp, j);
-        customLog(constraintName + " dual = " + dualValue);
+    customLog(constraintName + " dual = " + dualValue);
-    }
+  }
   customLog("");
 }
 
 function downloadLPFormatting(objective: any, subject: any, bounds: any) {
-  customLog("Preparing file content string...<br>");
+  customLog(getTranslation("downloadPrepFileString"));
-  
+  customLog("");
+
   // ensure that all vars are strings
   const formattedObjective = typeof objective === 'string' ? objective : '';
   const formattedSubject = typeof subject === 'string' ? subject : '';
   const formattedBounds = typeof bounds === 'string' ? bounds : '';
 
+  // fetch operator
+  const maxmin = (document.getElementById('maxminswitch') as HTMLSelectElement)?.value;
+  let operator = "Minimize";
+  if (maxmin == "maximize") operator = "Maximize";
+
   // Header mit Problemname
   const header = "\\ Your problem\n";
 
   //  format objective
-  const objectiveFunction = `Maximize\n obj: ${formattedObjective}\n`;
+
+  const objectiveFunction = operator + `\n obj: ${formattedObjective}\n`;
 
   // turn each subject into a single line
   const constraints = `Subject To\n${formattedSubject.split("\n").filter(line => line.trim() !== "").map(line => ` ${line}`).join("\n")}\n`;
@@ -274,23 +309,23 @@ function downloadLPFormatting(objective: any, subject: any, bounds: any) {
   return lpFormat;
 }
 
-
-
-
 function downloadProblemDownload(content: string) {
-  customLog("Preparing file...<br>")
+  customLog("downloadPrepFile");
+  customLog("");
   const blob = new Blob([content], { type: 'text/plain' });
   const link = document.createElement('a');
   link.href = URL.createObjectURL(blob);
   link.download = 'problem.txt'; // file name
   link.click(); // starting download
-  customLog("Starting download.")
+  customLog("downloadStart");
 }
 
 export function downloadLP() {
   customLogClear();
-  customLog("Preparing download...<br>");
+  customLog("downloadPrep");
-  customLog("Fetching input...<br>")
+  customLog("");
+  customLog("downloadFetchInput");
+  customLog("");
 
   let objective: string | undefined;
   const objectiveElement = document.getElementById('objective');
@@ -335,7 +370,7 @@ export function downloadLP() {
 
 
 export function import_click() {
-  console.log("Importing...");
+  console.log("importing");
 }