package fr.themode.engine.graphic;

import static org.lwjgl.opengl.GL11.*;
import static org.lwjgl.stb.STBTruetype.*;
import static org.lwjgl.system.MemoryStack.stackPush;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.FloatBuffer;

import org.lwjgl.BufferUtils;
import org.lwjgl.stb.STBTTAlignedQuad;
import org.lwjgl.stb.STBTTBakedChar;
import org.lwjgl.system.MemoryStack;

import fr.themode.engine.util.IOUtil;

public class Font {

	private String path;
	private int size;
	private int texID;

	private STBTTBakedChar.Buffer cdata;

	public Font(String path, int size) {
		this.path = path;
		this.size = size;
	}

	public void draw(String text, float x, float y, FontStyle style, Color color) {
		if (!isLoaded())
			cdata = load();

		switch (style) {
		case LEFT:
			x -= getWidth(text);
			break;
		case CENTERED:
			x -= getWidth(text) / 2;
			break;
		case RIGHT:
			break;
		}

		try (MemoryStack stack = stackPush()) {
			FloatBuffer xx = stack.floats(0.0f);
			FloatBuffer yy = stack.floats(0.0f);
			STBTTAlignedQuad q = STBTTAlignedQuad.mallocStack(stack);
			glPushMatrix();
			glBindTexture(GL_TEXTURE_2D, texID);

			glTranslatef(x, y, 0f);
			glColor4f((float) color.r / 255, (float) color.g / 255, (float) color.b / 255, color.a);
			glBegin(GL_QUADS);
			for (int i = 0; i < text.length(); i++) {
				char c = text.charAt(i);
				if (c == '\n') {
					yy.put(0, yy.get(0) + size);
					xx.put(0, 0.0f);
					continue;
				} else if (c < 32 || 128 <= c)
					continue;
				stbtt_GetBakedQuad(cdata, 512, 512, c - 32, xx, yy, q, true);
				glTexCoord2f(q.s0(), q.t0());
				glVertex2f(q.x0(), q.y0());

				glTexCoord2f(q.s1(), q.t0());
				glVertex2f(q.x1(), q.y0());

				glTexCoord2f(q.s1(), q.t1());
				glVertex2f(q.x1(), q.y1());

				glTexCoord2f(q.s0(), q.t1());
				glVertex2f(q.x0(), q.y1());
			}
			glEnd();

			glColor4f(1, 1, 1, 1);

			glPopMatrix();
		}
	}

	private STBTTBakedChar.Buffer load() {
		texID = glGenTextures();
		STBTTBakedChar.Buffer cdata = STBTTBakedChar.malloc(96);

		try {
			ByteBuffer ttf = IOUtil.ioResourceToByteBuffer(path, 160 * 1024);

			ByteBuffer bitmap = BufferUtils.createByteBuffer(512 * 512);
			stbtt_BakeFontBitmap(ttf, size, bitmap, 512, 512, 32, cdata);

			glBindTexture(GL_TEXTURE_2D, texID);
			glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, 512, 512, 0, GL_ALPHA, GL_UNSIGNED_BYTE, bitmap);
			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
		} catch (IOException e) {
			throw new RuntimeException(e);
		}

		return cdata;
	}

	public float getWidth(String text) {
		if (text == null || text.equals(""))
			return 0;
		float length;

		try (MemoryStack stack = stackPush()) {
			FloatBuffer xx = stack.floats(0.0f);
			FloatBuffer yy = stack.floats(0.0f);
			STBTTAlignedQuad q = STBTTAlignedQuad.mallocStack(stack);
			for (int i = 0; i < text.length(); i++) {
				char c = text.charAt(i);
				if (c == '\n') {
					yy.put(0, yy.get(0) + size);
					xx.put(0, 0.0f);
					continue;
				} else if (c < 32 || 128 <= c)
					continue;
				stbtt_GetBakedQuad(cdata, 512, 512, c - 32, xx, yy, q, true);
			}
			length = q.x1();
		}

		return length;
	}

	private boolean isLoaded() {
		return texID > 0;
	}

	public enum FontStyle {
		RIGHT, LEFT, CENTERED;
	}
}