package slim.test.example;

import static org.lwjgl.opengl.GL11.GL_CLAMP;
import static org.lwjgl.opengl.GL11.GL_NEAREST;
import static org.lwjgl.opengl.GL11.GL_PACK_ALIGNMENT;
import static org.lwjgl.opengl.GL11.GL_RGBA;
import static org.lwjgl.opengl.GL11.GL_TEXTURE_2D;
import static org.lwjgl.opengl.GL11.GL_TEXTURE_MAG_FILTER;
import static org.lwjgl.opengl.GL11.GL_TEXTURE_MIN_FILTER;
import static org.lwjgl.opengl.GL11.GL_TEXTURE_WRAP_S;
import static org.lwjgl.opengl.GL11.GL_TEXTURE_WRAP_T;
import static org.lwjgl.opengl.GL11.GL_UNPACK_ALIGNMENT;
import static org.lwjgl.opengl.GL11.GL_UNSIGNED_BYTE;
import static org.lwjgl.opengl.GL11.glBindTexture;
import static org.lwjgl.opengl.GL11.glEnable;
import static org.lwjgl.opengl.GL11.glGenTextures;
import static org.lwjgl.opengl.GL11.glPixelStorei;
import static org.lwjgl.opengl.GL11.glTexImage2D;
import static org.lwjgl.opengl.GL11.glTexParameteri;

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.nio.ByteBuffer;

import org.lwjgl.BufferUtils;

import slim.texture.io.PNGDecoder;
import slim.texture.io.PNGDecoder.Format;

public class Texture {
    static int bound = 0;

    public final int target = GL_TEXTURE_2D;
    public final int id;
    public final int width;
    public final int height;

    public static void clearLastBind() {
        bound = 0;
    }

    public Texture(URL pngRef) throws IOException {
        this(pngRef, GL_NEAREST);
    }

    public Texture(URL pngRef, int filter) throws IOException {
        this(pngRef, filter, GL_CLAMP);
    }

    public Texture(URL pngRef, int filter, int wrap) throws IOException {
        InputStream input = null;
        try {
            input = pngRef.openStream();
            PNGDecoder dec = new PNGDecoder(input);

            width = dec.getWidth();
            height = dec.getHeight();
            ByteBuffer buf = BufferUtils.createByteBuffer(4 * width * height);
            dec.decode(buf, width * 4, Format.RGBA);
            buf.flip();

            glEnable(target);
            id = glGenTextures();

            bind();

            glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
            glPixelStorei(GL_PACK_ALIGNMENT, 1);

            glTexParameteri(target, GL_TEXTURE_MIN_FILTER, filter);
            glTexParameteri(target, GL_TEXTURE_MAG_FILTER, filter);
            glTexParameteri(target, GL_TEXTURE_WRAP_S, wrap);
            glTexParameteri(target, GL_TEXTURE_WRAP_T, wrap);

            glTexImage2D(target, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, buf);
        } finally {
            if (input!=null) {
                try { input.close(); } catch (IOException e) {}
            }
        }
    }

    public void bind() {
        if (id != bound)
            glBindTexture(target, id);
    }
}