#include"root.h"
#include"text.h"
#include"shader.h"
#include"texture.h"
#include"node.h"
#include<glad.h>
#include<glfw3.h>
#include<iostream>
#include<ft2build.h>
#include FT_FREETYPE_H

using namespace std;

namespace vb01{
	Text::Text(string fontPath, string entry){
		initFont(fontPath);
		setText(entry);
	}

	Text::~Text(){
		delete shader;

		glDeleteVertexArrays(1, &VAO);
		glDeleteBuffers(1, &VBO);
	}

	void Text::initFont(string fontPath){
		string basePath = "../../vb01/text.";
		shader = new Shader(basePath + "vert", basePath + "frag");

		FT_Library ft;
		FT_Face face;
		if(FT_Init_FreeType(&ft))
			cout << "Couldn't init Freetype\n";	
		if(FT_New_Face(ft, fontPath.c_str(), 0, &face))
			cout << "Could not load font\n";

		FT_Set_Pixel_Sizes(face, 0, 100);

		glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

		for(u32 i = 0; i < 256; i++){
			if(FT_Load_Char(face, i, FT_LOAD_RENDER)){
				cout << "Could not load glyph\n";
				continue;
			}
			Glyph c;
			c.ch = i;
			c.texture = new Texture(face, i);		
			c.size = Vector2(face->glyph->bitmap.width, face->glyph->bitmap.rows);
			c.bearing = Vector2(face->glyph->bitmap_left, face->glyph->bitmap_top);
			c.advance = face->glyph->advance.x;
			characters.push_back(c);
		}

		FT_Done_Face(face);
		FT_Done_FreeType(ft);
	}

	void Text::update(){
		Root *root = Root::getSingleton();
		int width = root->getWidth(), height=root->getHeight();

		shader->use();
		shader->setVec4(color, "color");
		shader->setVec2(Vector2(width, height), "screen");
		shader->setVec3(node->getPosition(), "pos");

		renderGlyphs();
	}

	void Text::renderGlyphs(){
		Vector3 origin = node->getPosition();
		for(int i = 0; i < entry.length(); i++){
			Glyph ch;
			bool foundChar = false;
			for(Glyph c : characters)
				if(entry.c_str()[i] == c.ch){
					ch = c;
					foundChar = true;
				}
			if(!foundChar)
				continue;

			Vector2 size = ch.size * scale, bearing = ch.bearing * scale;
			float data[] = {
				origin.x + bearing.x, origin.y - bearing.y, 0, 0,
				origin.x + bearing.x + size.x, origin.y - bearing.y, 1, 0,
				origin.x + bearing.x + size.x, origin.y - bearing.y + size.y, 1, 1,

				origin.x + bearing.x + size.x, origin.y - bearing.y + size.y, 1, 1,
				origin.x + bearing.x, origin.y - bearing.y + size.y, 0, 1,
				origin.x + bearing.x, origin.y - bearing.y, 0, 0
			};

			origin.x += (ch.advance >> 6) * scale;
			glBindVertexArray(VAO);
			glBindBuffer(GL_ARRAY_BUFFER, VBO);
			glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(data), data);
			ch.texture->select();
			glDrawArrays(GL_TRIANGLES, 0, 6);	
		}
	}

	void Text::setText(string text){
		this->entry = text;

		glGenVertexArrays(1, &VAO);
		glGenBuffers(1, &VBO);
		glBindVertexArray(VAO);
		glBindBuffer(GL_ARRAY_BUFFER, VBO);
		glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 6 * 4, NULL, GL_DYNAMIC_DRAW);
		glEnableVertexAttribArray(0);
		glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 4 * sizeof(float), (void*)0);
		glBindBuffer(GL_ARRAY_BUFFER, 0);
		glBindVertexArray(0);
	}

	float Text::getCharWidth(char c){
		for(Glyph g : characters)
			if(g.ch == c)
				return g.size.x * scale;
	}
}