Initial commit.

.gitignore

@@ -0,0 +1 @@
+/target

LICENSE

@@ -0,0 +1,17 @@
+Copyright (C) 2026 Nicolás A. Ortega Froysa <nicolas@ortegas.org>
+
+This software is provided 'as-is', without any express or implied
+warranty.  In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not
+   claim that you wrote the original software. If you use this software
+   in a product, an acknowledgment in the product documentation would be
+   appreciated but is not required.
+2. Altered source versions must be plainly marked as such, and must not be
+   misrepresented as being the original software.
+3. This notice may not be removed or altered from any source distribution.

README.md

@@ -0,0 +1,39 @@
+# VacCalc
+
+## Building
+
+### Prerequisites
+
+- Java 11 or higher
+- Maven 3.6 or higher
+
+### Compile
+
+```bash
+mvn clean compile
+```
+
+### Package
+
+```bash
+mvn package
+```
+
+### Run
+
+Using Maven:
+
+```bash
+mvn exec:java@com.calendar.CalendarApp
+```
+
+Using Java directly:
+
+```bash
+java -jar target/vaccalc-1.0.0.jar
+```
+
+## License
+
+This project is licensed under the Zlib license. See the [license](LICENSE)
+file for more information.

pom.xml

@@ -0,0 +1,66 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0
+         http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>com.calendar</groupId>
+    <artifactId>vaccalc</artifactId>
+    <version>1.0.0</version>
+    <packaging>jar</packaging>
+
+    <name>VacCalc</name>
+    <description>Vacation Calculator - A calendar app to calculate vacation days in a point-based system.</description>
+
+    <properties>
+        <maven.compiler.source>11</maven.compiler.source>
+        <maven.compiler.target>11</maven.compiler.target>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.13.2</version>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <version>3.8.1</version>
+                <configuration>
+                    <source>11</source>
+                    <target>11</target>
+                </configuration>
+            </plugin>
+
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-jar-plugin</artifactId>
+                <version>3.2.0</version>
+                <configuration>
+                    <archive>
+                        <manifest>
+                            <mainClass>net.themusicinnoise.vaccalc.VacCalc</mainClass>
+                        </manifest>
+                    </archive>
+                </configuration>
+            </plugin>
+
+            <plugin>
+                <groupId>org.codehaus.mojo</groupId>
+                <artifactId>exec-maven-plugin</artifactId>
+                <version>3.0.0</version>
+                <configuration>
+                    <mainClass>net.themusicinnoise.vaccalc.VacCalc</mainClass>
+                </configuration>
+            </plugin>
+        </plugins>
+    </build>
+</project>

src/main/java/net/themusicinnoise/vaccalc/CalendarPanel.java

@@ -0,0 +1,106 @@
+package net.themusicinnoise.vaccalc;
+
+import javax.swing.*;
+import java.awt.*;
+import java.time.LocalDate;
+import java.time.YearMonth;
+import java.time.DayOfWeek;
+
+public class CalendarPanel extends JPanel {
+    private YearMonth currentMonth;
+    private final int cellHeight = 60;
+    private final int cellWidth = 80;
+
+    public CalendarPanel() {
+        this.currentMonth = YearMonth.now();
+        setPreferredSize(new Dimension(7 * cellWidth, 8 * cellHeight));
+        setBackground(Color.WHITE);
+    }
+
+    public void previousMonth() {
+        currentMonth = currentMonth.minusMonths(1);
+        repaint();
+    }
+
+    public void nextMonth() {
+        currentMonth = currentMonth.plusMonths(1);
+        repaint();
+    }
+
+    public YearMonth getCurrentMonth() {
+        return currentMonth;
+    }
+
+    public void setCurrentMonth(YearMonth month) {
+        currentMonth = month;
+        repaint();
+    }
+
+    @Override
+    protected void paintComponent(Graphics g) {
+        super.paintComponent(g);
+        Graphics2D g2 = (Graphics2D) g;
+        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
+
+        drawDayHeaders(g2);
+        drawDays(g2);
+    }
+
+    private void drawDayHeaders(Graphics2D g) {
+        String[] dayNames = {"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
+        g.setColor(new Color(70, 130, 180));
+        g.fillRect(0, 0, 7 * cellWidth, cellHeight);
+
+        g.setColor(Color.WHITE);
+        g.setFont(new Font("Arial", Font.BOLD, 14));
+        FontMetrics fm = g.getFontMetrics();
+
+        for (int i = 0; i < 7; i++) {
+            String day = dayNames[i];
+            int x = i * cellWidth;
+            int textX = x + (cellWidth - fm.stringWidth(day)) / 2;
+            int textY = (cellHeight - fm.getHeight()) / 2 + fm.getAscent();
+            g.drawString(day, textX, textY);
+        }
+    }
+
+    private void drawDays(Graphics2D g) {
+        LocalDate firstDay = currentMonth.atDay(1);
+        int firstDayOfWeek = firstDay.getDayOfWeek().getValue() % 7;
+        int daysInMonth = currentMonth.lengthOfMonth();
+        LocalDate today = LocalDate.now();
+
+        g.setFont(new Font("Arial", Font.PLAIN, 14));
+        FontMetrics fm = g.getFontMetrics();
+
+        int row = 1;
+        int col = firstDayOfWeek;
+
+        for (int day = 1; day <= daysInMonth; day++) {
+            int x = col * cellWidth;
+            int y = row * cellHeight;
+
+            LocalDate cellDate = currentMonth.atDay(day);
+            boolean isToday = cellDate.equals(today);
+
+            if (isToday) {
+                g.setColor(new Color(255, 200, 100));
+                g.fillRect(x, y, cellWidth, cellHeight);
+            }
+
+            g.setColor(Color.BLACK);
+            g.drawRect(x, y, cellWidth, cellHeight);
+
+            String dayStr = String.valueOf(day);
+            int textX = x + (cellWidth - fm.stringWidth(dayStr)) / 2;
+            int textY = y + (cellHeight - fm.getHeight()) / 2 + fm.getAscent();
+            g.drawString(dayStr, textX, textY);
+
+            col++;
+            if (col == 7) {
+                col = 0;
+                row++;
+            }
+        }
+    }
+}

src/main/java/net/themusicinnoise/vaccalc/VacCalc.java

@@ -0,0 +1,81 @@
+package net.themusicinnoise.vaccalc;
+
+import javax.swing.*;
+import java.awt.*;
+import java.time.YearMonth;
+
+public class VacCalc extends JFrame {
+    private CalendarPanel calendarPanel;
+    private JLabel monthLabel;
+
+    public VacCalc() {
+        setTitle("VacCalc");
+        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+        setResizable(false);
+        setLocationRelativeTo(null);
+
+        calendarPanel = new CalendarPanel();
+
+        JPanel headerPanel = createHeaderPanel();
+        JPanel mainPanel = new JPanel(new BorderLayout());
+        mainPanel.add(headerPanel, BorderLayout.NORTH);
+        mainPanel.add(calendarPanel, BorderLayout.CENTER);
+
+        add(mainPanel);
+        pack();
+    }
+
+    private JPanel createHeaderPanel() {
+        JPanel headerPanel = new JPanel(new BorderLayout());
+        headerPanel.setBackground(new Color(230, 230, 230));
+        headerPanel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
+
+        monthLabel = new JLabel();
+        monthLabel.setFont(new Font("Arial", Font.BOLD, 18));
+        monthLabel.setHorizontalAlignment(JLabel.CENTER);
+
+        JButton prevButton = new JButton("< Previous");
+        prevButton.addActionListener(e -> {
+            calendarPanel.previousMonth();
+            updateMonthLabel();
+        });
+
+        JButton nextButton = new JButton("Next >");
+        nextButton.addActionListener(e -> {
+            calendarPanel.nextMonth();
+            updateMonthLabel();
+        });
+
+        JButton todayButton = new JButton("Today");
+        todayButton.addActionListener(e -> {
+            calendarPanel.setCurrentMonth(YearMonth.now());
+            updateMonthLabel();
+        });
+
+        JPanel buttonPanel = new JPanel(new FlowLayout(FlowLayout.CENTER, 10, 0));
+        buttonPanel.setBackground(new Color(230, 230, 230));
+        buttonPanel.add(prevButton);
+        buttonPanel.add(todayButton);
+        buttonPanel.add(nextButton);
+
+        headerPanel.add(monthLabel, BorderLayout.CENTER);
+        headerPanel.add(buttonPanel, BorderLayout.SOUTH);
+
+        updateMonthLabel();
+        return headerPanel;
+    }
+
+    private void updateMonthLabel() {
+        YearMonth current = calendarPanel.getCurrentMonth();
+        monthLabel.setText(String.format("%s %d", 
+            current.getMonth().toString(), 
+            current.getYear()));
+    }
+
+    public static void main(String[] args) {
+        SwingUtilities.invokeLater(() -> {
+            VacCalc app = new VacCalc();
+            app.setVisible(true);
+        });
+    }
+}