package de.finalspace.lwjgltest;

import java.awt.Canvas;
import java.awt.Component;
import java.awt.event.ComponentAdapter;
import java.awt.event.ComponentEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.image.BufferedImage;
import java.awt.image.DataBufferByte;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.FloatBuffer;
import java.nio.ShortBuffer;

import javax.imageio.ImageIO;
import javax.swing.JFrame;
import javax.swing.WindowConstants;

import org.lwjgl.input.Keyboard;
import org.lwjgl.input.Mouse;
import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.GL11;
import org.lwjgl.opengl.GL12;
import org.lwjgl.opengl.GL13;
import org.lwjgl.opengl.GL15;
import org.lwjgl.opengl.GL20;

public class LWJGLTextureTest extends JFrame {
    private static final long serialVersionUID = -3422852982258512645L;
    private final Canvas canvas;
    private boolean isRunning;

    private int shaderID;
    private int vertexAttribLocation;
    private int texcoordAttribLocation;

    private int textureID;
    private int textureSamplerLocation;

    private int indexCount;
    private int texcoordOffset;
    private int vboID;
    private int iboID;

    private final String vertShaderSource = "" +
        "attribute vec4 vPosition;\n"+
        "attribute vec2 vTexcoord;\n"+
        "varying vec2 texcoord;\n"+
        "void main() {\n"+
        "   gl_Position = vPosition;\n"+
        "   texcoord = vTexcoord;\n"+
        "}\n";

    private final String fragShaderSource = "\n" +
            "uniform sampler2D uTexture;\n"+
            "varying vec2 texcoord;\n"+
            "void main() {\n"+
            "   vec4 texColor = texture2D(uTexture, texcoord);\n"+
            "   gl_FragColor = texColor;\n"+
            "   //gl_FragColor = vec4(texcoord.x, texcoord.y, 0.0, 1.0);\n"+
            "}\n";

    public LWJGLTextureTest() {
        super();
        // Setup native lwjgl path
        File nativePath = new File(System.getProperty("user.dir"),
                "lwjgl-2.9.0/native/linux");
        System.out.println(nativePath);
        System.setProperty("org.lwjgl.librarypath",
                nativePath.getAbsolutePath());

        // Initialize canvas
        canvas = new Canvas();
        canvas.setSize(800, 600);
        add(canvas);

        this.setTitle("Texture test");
        setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE);
        this.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                isRunning = false;
            }

            @Override
            public void windowLostFocus(WindowEvent e) {
            }

            @Override
            public void windowGainedFocus(WindowEvent e) {
            }
        });
        this.addComponentListener(new ComponentAdapter() {
            @Override
            public void componentResized(ComponentEvent evt) {
                Component c = (Component) evt.getSource();
                canvas.setSize(c.getWidth(), c.getHeight());
            }
        });
    }

    void handleEvents() {
        // Keyboard events
        while (Keyboard.next()) {
        }

        // Mouse events
        while (Mouse.next()) {
        }
    }

    private void update() {

    }

    private void draw() {
        GL11.glClear(GL11.GL_COLOR_BUFFER_BIT | GL11.GL_DEPTH_BUFFER_BIT);

        GL13.glActiveTexture(GL13.GL_TEXTURE0);
        GL11.glEnable(GL11.GL_TEXTURE_2D);
        GL11.glBindTexture(GL11.GL_TEXTURE_2D, textureID);

        GL20.glUseProgram(shaderID);
        GL20.glUniform1i(textureSamplerLocation, 0);

        GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vboID);

        GL20.glEnableVertexAttribArray(vertexAttribLocation);
        GL20.glVertexAttribPointer(vertexAttribLocation, 3, GL11.GL_FLOAT, false, 3 * 4, 0);

        GL20.glEnableVertexAttribArray(texcoordAttribLocation);
        GL20.glVertexAttribPointer(texcoordAttribLocation, 2, GL11.GL_FLOAT, false, 2 * 4, texcoordOffset);

        GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, iboID);
        GL11.glDrawElements(GL11.GL_TRIANGLES, indexCount, GL11.GL_UNSIGNED_SHORT, 0);
        GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, 0);

        GL20.glDisableVertexAttribArray(texcoordAttribLocation);
        GL20.glDisableVertexAttribArray(vertexAttribLocation);

        GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, 0);

        GL20.glUseProgram(0);

        GL13.glActiveTexture(GL13.GL_TEXTURE0);
        GL11.glBindTexture(GL11.GL_TEXTURE_2D, 0);
        GL11.glDisable(GL11.GL_TEXTURE_2D);
    }

    private int _loadShader(final String name, final int type,
            final String source) {
        // Create a new shader object
        int shader = GL20.glCreateShader(type);

        // Pass the shader source
        GL20.glShaderSource(shader, source);

        // Compile shader
        GL20.glCompileShader(shader);

        // Get compilation status
        final int compileStatus = GL20.glGetShaderi(shader,
                GL20.GL_COMPILE_STATUS);

        // If the compilation failed, delete the shader.
        String infoLog = GL20.glGetShaderInfoLog(shader, 1024);
        if (compileStatus == 0) {
            String shaderType = type == GL20.GL_FRAGMENT_SHADER ? "Fragment"
                    : "Vertex";
            GL20.glDeleteShader(shader);
            throw new IllegalArgumentException(shaderType + " shader '" + name
                    + "' could not compile: " + infoLog);
        } else {
            System.out.println(infoLog);
        }

        return shader;
    }

    private int loadShaders(final String name, final String vertSource,
            final String fragSource) {
        int program = GL20.glCreateProgram();

        // Load vertex shader
        int vertexShader = _loadShader(name, GL20.GL_VERTEX_SHADER, vertSource);

        // Load fragment shader
        int fragShader = _loadShader(name, GL20.GL_FRAGMENT_SHADER, fragSource);

        // Bind the vertex shader to the program.
        GL20.glAttachShader(program, vertexShader);

        // Bind the fragment shader to the program.
        GL20.glAttachShader(program, fragShader);

        // Link the two shaders together into a program.
        GL20.glLinkProgram(program);

        // Delete both shaders, does not matter when compile failed or was
        // successfully
        GL20.glDeleteShader(fragShader);
        GL20.glDeleteShader(vertexShader);

        // If the link failed, delete the program.
        final int linkStatus = GL20.glGetProgrami(program, GL20.GL_LINK_STATUS);
        if (linkStatus == 0) {
            String infoLog = GL20.glGetProgramInfoLog(program, 1024);
            GL20.glDeleteProgram(program);
            throw new IllegalStateException("Program '" + name
                    + "' could not link: " + infoLog);
        }

        return program;
    }

//  private String streamToText(final InputStream inputStream) {
//      InputStreamReader reader = new InputStreamReader(inputStream);
//      char[] buffer = new char[256];
//      int read = 0;
//      StringBuffer out = new StringBuffer();
//      try {
//          while ((read = reader.read(buffer)) > 0) {
//              out.append(buffer, 0, read);
//          }
//          return out.toString();
//      } catch (IOException e) {
//          e.printStackTrace();
//      }
//      return null;
//  }

    private ByteBuffer getImageData(final BufferedImage image) {
        byte[] imageData = ((DataBufferByte) image.getRaster().getDataBuffer())
                .getData();
        byte[] buffer = new byte[image.getWidth() * image.getHeight() * 4];

        int c = 0;
        for (int i = 0; i < imageData.length; i += 3) {
            buffer[c] = imageData[i + 2]; // * Rot *
            buffer[c + 1] = imageData[i + 1]; // * Gruen *
            buffer[c + 2] = imageData[i]; // * Blau *
            buffer[c + 3] = (byte) 255; // * Alpha *
            c += 4;
        }

        ByteBuffer textureData = ByteBuffer.allocateDirect(buffer.length);
        textureData.order(ByteOrder.nativeOrder());
        textureData.put(buffer, 0, buffer.length);
        textureData.flip();

        return textureData;
    }

    private int loadTexture(final String name, final InputStream inputStream) {
        BufferedImage image;
        try {
            image = ImageIO.read(inputStream);
        } catch (IOException e) {
            throw new IllegalStateException("Could not read texture '" + name
                    + "'!", e);
        }

        int width = image.getWidth();
        int height = image.getHeight();

        ByteBuffer data = getImageData(image);

        int handle = GL11.glGenTextures();
        int target = GL11.GL_TEXTURE_2D;
        GL11.glBindTexture(target, handle);
        GL11.glTexParameteri(target, GL11.GL_TEXTURE_WRAP_S,
                GL12.GL_CLAMP_TO_EDGE);
        GL11.glTexParameteri(target, GL11.GL_TEXTURE_WRAP_T,
                GL12.GL_CLAMP_TO_EDGE);
        GL11.glTexParameterf(target, GL11.GL_TEXTURE_MIN_FILTER,
                GL11.GL_NEAREST);
        GL11.glTexParameterf(target, GL11.GL_TEXTURE_MAG_FILTER, GL11.GL_LINEAR);
        GL11.glBindTexture(target, 0);
        GL11.glTexImage2D(target, 0, GL11.GL_RGBA8, width, height, 0,
                GL11.GL_RGBA, GL11.GL_UNSIGNED_BYTE, data);
        return handle;
    }

    private void createQuad(final float width, final float height) {
        float[] verts = new float[] { -width / 2, height / 2, 0.0f, // top left
                width / 2, height / 2, 0.0f, // top right
                width / 2, -height / 2, 0.0f, // bottom right
                -width / 2, -height / 2, 0.0f // bottom left
        };
        final float[] texcoords = new float[] { 0.0f, 1.0f, 1.0f, 1.0f, 1.0f,
                0.0f, 0.0f, 0.0f };
        short[] index = new short[] { 1, 0, 3, 3, 2, 1 };

        final int vertsSize = verts.length * 4;

        final int texcoordsSize = texcoords.length * 4;

        final int indicesSize = index.length * 2;

        final int size = vertsSize + texcoordsSize;

        texcoordOffset = vertsSize;
        indexCount = index.length;

        FloatBuffer vertBuffer = ByteBuffer.allocateDirect(vertsSize)
                .order(ByteOrder.nativeOrder()).asFloatBuffer();
        vertBuffer.put(verts);
        vertBuffer.flip();

        FloatBuffer texcoordBuffer = ByteBuffer.allocateDirect(texcoordsSize)
                .order(ByteOrder.nativeOrder()).asFloatBuffer();
        texcoordBuffer.put(texcoords);
        texcoordBuffer.flip();

        ShortBuffer indexBuffer = ByteBuffer.allocateDirect(indicesSize)
                .order(ByteOrder.nativeOrder()).asShortBuffer();
        indexBuffer.put(index);
        indexBuffer.flip();

        vboID = GL15.glGenBuffers();
        GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, vboID);
        GL15.glBufferData(GL15.GL_ARRAY_BUFFER, size, GL15.GL_STATIC_DRAW);
        GL15.glBufferSubData(GL15.GL_ARRAY_BUFFER, 0, vertBuffer);
        GL15.glBufferSubData(GL15.GL_ARRAY_BUFFER, vertsSize, texcoordBuffer);
        GL15.glBindBuffer(GL15.GL_ARRAY_BUFFER, 0);

        iboID = GL15.glGenBuffers();
        GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, iboID);
        GL15.glBufferData(GL15.GL_ELEMENT_ARRAY_BUFFER, indexBuffer, GL15.GL_STATIC_DRAW);
        GL15.glBindBuffer(GL15.GL_ELEMENT_ARRAY_BUFFER, 0);
    }

    private InputStream loadResource(final String name) {
        return getClass().getClassLoader().getResourceAsStream(name);
    }

    private void init() {
        // Create vbo and ibo
        createQuad(1.0f, 1.0f);
        System.out.println("vbo id: " + vboID);
        System.out.println("ibo id: " + iboID);

        // Load shader
        shaderID = loadShaders("simple", vertShaderSource, fragShaderSource);
        System.out.println("shader id: " + shaderID);

        // Get shader locations
        GL20.glUseProgram(shaderID);
        textureSamplerLocation = GL20.glGetUniformLocation(shaderID, "uTexture");
        vertexAttribLocation = GL20.glGetAttribLocation(shaderID, "vPosition");
        texcoordAttribLocation = GL20.glGetAttribLocation(shaderID, "vTexcoord");
        GL20.glUseProgram(0);
        System.out.println("uTexture location: " + textureSamplerLocation);
        System.out.println("vPosition location: " + vertexAttribLocation);
        System.out.println("vTexcoord location: " + texcoordAttribLocation);

        // Load texture
        textureID = loadTexture("test.jpg", loadResource("textures/test.jpg"));
        System.out.println("texture id: " + textureID);

        GL11.glClearColor(1.0f, 0.0f, 1.0f, 1.0f);
    }

    public void run() {
        isRunning = true;
        this.pack();
        this.setVisible(true);
        this.requestFocus();
        canvas.requestFocusInWindow();
        try {
            Display.setParent(canvas);
            Display.create();
            init();
            while (isRunning) {
                Display.sync(60);
                handleEvents();
                update();
                draw();
                Display.update();
            }
            Display.destroy();
        } catch (Exception e) {
            e.printStackTrace();
        }
        System.exit(0);
    }

    public static void main(String[] args) {
        LWJGLTextureTest app = new LWJGLTextureTest();
        app.run();
    }
}