#include "Texture.hpp"

#include "Map.hpp"

#include "Strings.hpp"

#include "Shader.hpp"

#include "GraphicsApi.hpp"

const char* texture_vertex =
#ifdef ENV_OS_ANDROID
"#version 300 es\n"
"precision mediump float;\n"
#else
"#version 330 core\n"
#endif
"layout(location = 0) in vec3 vPos;\n"
"out vec2 UV;\n"
"void main() {\n"
"	gl_Position = vec4(vPos, 1);\n"
"	UV = (vPos.xy + vec2(1, 1)) / 2.0;\n"
"}\n";

const char* texture_fragment =
#ifdef ENV_OS_ANDROID
"#version 300 es\n"
"precision mediump float;\n"
#else
"#version 330 core\n"
#endif
"in vec2 UV;\n"
"out vec4 color;\n"
"uniform sampler2D renderedTexture;\n"
"uniform float time;\n"
"void main() {\n"
"	vec4 texColor = texture(renderedTexture, UV);\n"
" if (texColor.a < 0.2)\n"
"		discard;\n"
" color = texColor;\n"
"}\n";


using namespace tp;

GLuint RenderTexture::getid() { return id; }

RenderTexture::RenderTexture() {
	glGenTextures(1, &id);
	glBindTexture(GL_TEXTURE_2D, id);

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	glBindTexture(GL_TEXTURE_2D, 0);
}

RenderTexture::~RenderTexture() { glDeleteTextures(1, &id); }


void RenderTexture::update(const Buffer2D<RGBA>& buff) {
	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, (GLsizei)buff.size().x, (GLsizei)buff.size().y, 0, GL_RGBA, GL_FLOAT, buff.getBuff());
}

void RenderTexture::draw(const GLuint& out) {
	draw_texture(out, id);
}


struct texture_drawer_data {

	Map<String, GLuint> textures;

	GLuint quad_VertexArrayID;
	GLuint quad_vertexbuffer;
	GLuint texID;
	RenderShader shader;

	const GLfloat g_quad_vertex_buffer_data[18] = {
			-1.0f, -1.0f, 0.0f, 1.0f, -1.0f, 0.0f, -1.0f, 1.0f, 0.0f,
			-1.0f, 1.0f,  0.0f, 1.0f, -1.0f, 0.0f, 1.0f,  1.0f, 0.0f,
	};

	texture_drawer_data() : shader(texture_vertex, nullptr, texture_fragment, false) {
		// The fullscreen quad's FBO
		glGenVertexArrays(1, &quad_VertexArrayID);
		glBindVertexArray(quad_VertexArrayID);

		glGenBuffers(1, &quad_vertexbuffer);
		glBindBuffer(GL_ARRAY_BUFFER, quad_vertexbuffer);
		glBufferData(GL_ARRAY_BUFFER, sizeof(g_quad_vertex_buffer_data),
			g_quad_vertex_buffer_data, GL_STATIC_DRAW);

		texID = shader.getu("renderedTexture");
	}

	~texture_drawer_data() {
		glDeleteBuffers(1, &quad_vertexbuffer);
		glDeleteVertexArrays(1, &quad_VertexArrayID);

		for (auto tex : textures) {
			glDeleteTextures(1, &tex->val);
		}
	}
};

texture_drawer_data* texdd = NULL;

void RenderTexture::init() {
	if (!texdd) texdd = new texture_drawer_data();
}

void RenderTexture::deinit() {
	if (texdd) delete texdd;
	texdd = NULL;
}

void RenderTexture::draw_texture(uint4 out, uint4 in) {
	ASSERT(in);

	// Render to the screen
	glBindFramebuffer(GL_FRAMEBUFFER, out);

	// Use our shader
	texdd->shader.bind();

	// Bind our texture in Texture Unit 0
	glActiveTexture(GL_TEXTURE0);
	glBindTexture(GL_TEXTURE_2D, in);
	// Set our "renderedTexture" sampler to use Texture Unit 0
	glUniform1i(texdd->texID, 0);

	// glUniformMatrix4fv(texdd->rect_mat, 1, GL_FALSE, &tmat[0][0]);

	// 1rst attribute buffer : vertices
	glEnableVertexAttribArray(0);
	glBindBuffer(GL_ARRAY_BUFFER, texdd->quad_vertexbuffer);
	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, (void*)0);

	// Draw the triangles. 2*3 indices starting at 0 -> 2 triangles
	glDrawArrays(GL_TRIANGLES, 0, 6);

	glDisableVertexAttribArray(0);

	texdd->shader.unbind();
}

GLuint load_texture(const String& name) {
	GLuint tex_2d = 0;

	ASSERT(0 && "incomplete compilation - no SOIL support added");

	if (0) {
		//auto document = lunasvg::Document::loadFromFile("tiger.svg");
		//auto bitmap = document->renderToBitmap();
	}
	else {
		/*
		tex_2d = SOIL_load_OGL_texture(
			name.cstr(), SOIL_LOAD_RGBA, SOIL_CREATE_NEW_ID,
			SOIL_FLAG_MIPMAPS | SOIL_FLAG_INVERT_Y | SOIL_FLAG_NTSC_SAFE_RGB |
			SOIL_FLAG_COMPRESS_TO_DXT);

		if (0 == tex_2d) {
			printf("SOIL loading error: '%s'\n", SOIL_last_result());
		}
		*/
	}

	return tex_2d;
}

GLuint RenderTexture::get_tex(const char* TexId) {
	GLuint out = 0;
	auto idx = texdd->textures.presents(TexId);
	if (idx) {
		out = texdd->textures.get(TexId);
	}
	else {
		out = load_texture(TexId);
		texdd->textures.put(TexId, out);
	}
	return out;
}

void RenderTexture::drawCurcle(Vec2F pos, double radius, RGBA col) {
#ifndef ENV_OS_ANDROID
	static alni precision = 40;

	glColor4f(col.r, col.g, col.b, col.a);

	double twicePi = 2.0 * 3.142;

	glBegin(GL_TRIANGLE_FAN);  // BEGIN CIRCLE
	glVertex2f(pos.x, pos.y);  // center of circle

	for (alni i = 0; i <= precision; i++) {
		glVertex2f((GLfloat)(pos.x + (radius * cos(i * twicePi / precision))),
			(GLfloat)(pos.y + (radius * sin(i * twicePi / precision))));
	}
	glEnd();  // END
#endif 
}