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package demominer.gui.drawer;

import demominer.UI.component.Component;
import demominer.UI.component.Container;
import demominer.resources.Resources;
import demominer.sprite.SpriteImage;
import demominer.sprite.SpriteSheet;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.IntBuffer;


import org.lwjgl.LWJGLException;
import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.DisplayMode;
import org.lwjgl.opengl.EXTFramebufferObject;
import org.lwjgl.opengl.GL11;

/**
 *
 * @author Szoltomi
 */
public class DrawerMethods extends Thread {

    /**
     * Initializes OpenGL.
     *
     * Called before the start of the drawing thread.
     * Only basic OpenGL calls, shouldn't need explanation.
     *
     * @param width the width of the window
     * @param height the height of the window
     */
    public static void initDraw(int width, int height) {
        try {
            Display.setDisplayMode(new DisplayMode(width, height));
            Display.create();
        } catch (LWJGLException e) {
            e.printStackTrace();
            System.exit(0);
        }
        GL11.glMatrixMode(GL11.GL_PROJECTION);
        GL11.glLoadIdentity();
        GL11.glOrtho(0, width, 0, height, -1000, 1000);
        GL11.glMatrixMode(GL11.GL_MODELVIEW);
        GL11.glEnable(GL11.GL_BLEND);
        GL11.glEnable(GL11.GL_TEXTURE_2D);
        GL11.glDisable(GL11.GL_CULL_FACE);
        GL11.glBlendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA);
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MIN_FILTER, GL11.GL_NEAREST);
        GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MAG_FILTER, GL11.GL_NEAREST);
    }

    /**
     * Generates a texture-bound framebuffer object.
     *
     * @param width The width of the FBO and texture
     * @param height The height of the FBO and texture
     * @return An array with the ID of the FBO and the texture. The first element is the ID of the FBO, the second is the ID of the texture.
     */
    public static int[] initFBOTexture(int width, int height) {
        //Most of the code is copied out from a tutorial, and I can partially understand it.
        IntBuffer buffer = ByteBuffer.allocateDirect(1 * 4).order(ByteOrder.nativeOrder()).asIntBuffer();
        EXTFramebufferObject.glGenFramebuffersEXT(buffer);
        int FBOId = buffer.get();
        EXTFramebufferObject.glBindFramebufferEXT(EXTFramebufferObject.GL_FRAMEBUFFER_EXT, FBOId);
        //setting up depthbuffer
        int depthbuffer = EXTFramebufferObject.glGenRenderbuffersEXT();
        EXTFramebufferObject.glBindRenderbufferEXT(EXTFramebufferObject.GL_RENDERBUFFER_EXT, depthbuffer);
        EXTFramebufferObject.glRenderbufferStorageEXT(EXTFramebufferObject.GL_RENDERBUFFER_EXT,
                                                      GL11.GL_DEPTH_COMPONENT,
                                                      width, height);
        EXTFramebufferObject.glFramebufferRenderbufferEXT(EXTFramebufferObject.GL_FRAMEBUFFER_EXT,
                                                          EXTFramebufferObject.GL_DEPTH_ATTACHMENT_EXT,
                                                          EXTFramebufferObject.GL_RENDERBUFFER_EXT, depthbuffer);
        //setting up color buffer
        int texId;
        texId = GL11.glGenTextures();
        GL11.glBindTexture(GL11.GL_TEXTURE_2D, texId);
        GL11.glTexImage2D(GL11.GL_TEXTURE_2D,
                          0,
                          GL11.GL_RGBA8,
                          width, height,
                          0,
                          GL11.GL_RGBA, GL11.GL_UNSIGNED_BYTE, (IntBuffer) null);

        EXTFramebufferObject.glFramebufferTexture2DEXT(EXTFramebufferObject.GL_FRAMEBUFFER_EXT,
                                                       EXTFramebufferObject.GL_COLOR_ATTACHMENT0_EXT,
                                                       GL11.GL_TEXTURE_2D,
                                                       texId, 0);
        EXTFramebufferObject.glBindFramebufferEXT(EXTFramebufferObject.GL_FRAMEBUFFER_EXT, 0);

        //Completeness check.
        int framebuffer = EXTFramebufferObject.glCheckFramebufferStatusEXT(EXTFramebufferObject.GL_FRAMEBUFFER_EXT);
        switch (framebuffer) {
            case EXTFramebufferObject.GL_FRAMEBUFFER_COMPLETE_EXT:
                break;
            case EXTFramebufferObject.GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT_EXT:
                throw new RuntimeException("FrameBuffer: " + FBOId
                                           + ", has caused a GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT_EXT exception");
            case EXTFramebufferObject.GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT_EXT:
                throw new RuntimeException("FrameBuffer: " + FBOId
                                           + ", has caused a GL_FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT_EXT exception");
            case EXTFramebufferObject.GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS_EXT:
                throw new RuntimeException("FrameBuffer: " + FBOId
                                           + ", has caused a GL_FRAMEBUFFER_INCOMPLETE_DIMENSIONS_EXT exception");
            case EXTFramebufferObject.GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER_EXT:
                throw new RuntimeException("FrameBuffer: " + FBOId
                                           + ", has caused a GL_FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER_EXT exception");
            case EXTFramebufferObject.GL_FRAMEBUFFER_INCOMPLETE_FORMATS_EXT:
                throw new RuntimeException("FrameBuffer: " + FBOId
                                           + ", has caused a GL_FRAMEBUFFER_INCOMPLETE_FORMATS_EXT exception");
            case EXTFramebufferObject.GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER_EXT:
                throw new RuntimeException("FrameBuffer: " + FBOId
                                           + ", has caused a GL_FRAMEBUFFER_INCOMPLETE_READ_BUFFER_EXT exception");
            default:
                throw new RuntimeException("Unexpected reply from glCheckFramebufferStatusEXT: " + framebuffer);
        }
        return new int[]{FBOId, texId};

    }

    /**
     * Binds a texture-bound FBO and the texture the FBO is bound to.
     *
     * The array has to contain the two elements returned with initFBOTexture(int width, int height).
     * It binds the FBO and texture, so that further drawing will be done on these.
     *
     * @param fbo An array with two elements: The first is the ID of the FBO, the second is the ID of the texture which the FBO is bound to.
     */
    public static void bindFBO(int[] fbo) {
        GL11.glBindTexture(GL11.GL_TEXTURE_2D, fbo[1]);
        EXTFramebufferObject.glBindFramebufferEXT(EXTFramebufferObject.GL_FRAMEBUFFER_EXT, fbo[0]);
    }

    /**
     * Unbinds the currently bound FBO, so that further drawing will occur on the window.
     */
    public static void unbindFBO() {
        EXTFramebufferObject.glBindFramebufferEXT(EXTFramebufferObject.GL_FRAMEBUFFER_EXT, 0);
    }

    /**
     * Sets the current color and alpha.
     * @param red
     * @param green
     * @param blue
     * @param alpha
     */
    public static void setColor(double red, double green, double blue, double alpha) {
        GL11.glColor4d(red, green, blue, alpha);
    }

    /**
     * Method for simple calling of GL11.glEnd();
     */
    public static void drawEnd() {
        GL11.glEnd();
    }

    /**
     * Clears the screen.
     */
    public static void clear() {
        GL11.glClear(GL11.GL_COLOR_BUFFER_BIT);
    }

    /**
     * Checks if any OpenGL errors have occured, prints it out if did.
     */
    public static void checkErrors() {
        int error = GL11.glGetError();
        if (error != 0) {
            System.out.println(error);
        }
    }

        /**
     * Translates and zooms the modelview.
     *
     * @param x translation horizontally, in pixels.
     * @param y translation vertically, in pixels.
     * @param zoom Magnification multiplicator. 1.0 means no magnification
     */
    public static void viewMatrix(long x, long y, double zoom) {
        GL11.glMatrixMode(GL11.GL_MODELVIEW);
        GL11.glLoadIdentity();
        GL11.glScaled(zoom, zoom, 0f);
        GL11.glTranslated(x, y, 0);
    }

    /**
     * Zooms the modelview in our out.
     *
     * @param Magnification multiplicator. 1.0 means no magnification
     */
    public static void viewZoom(double zoom) {
        GL11.glMatrixMode(GL11.GL_MODELVIEW);
        GL11.glLoadIdentity();
        GL11.glScaled(zoom, zoom, 0f);
    }

    /**
     * Flips the modelview upside down. Currently unused.
     */
    public static void flip() {
        GL11.glScaled(1f, -1f, 0f);
    }

    /**
     * Translates the modelview.
     * @param x translation horizontally, in pixels.
     * @param y translation vertically, in pixels.
     */
    public static void viewTranslation(long x, long y) {
        GL11.glMatrixMode(GL11.GL_MODELVIEW);
        GL11.glLoadIdentity();
        GL11.glTranslated(x, y, 0);
    }
}