#include <keys.h>
#include <graphics.h>
#include <math.h>

#include <orca.h>

vec2 frameSize = {100, 100};

mg_surface surface;

unsigned int program;

const char* vshaderSource =
	"attribute vec4 vPosition;\n"
	"uniform mat4 transform;\n"
	"void main()\n"
	"{\n"
	"   gl_Position = transform*vPosition;\n"
	"}\n";

const char* fshaderSource =
	"precision mediump float;\n"
	"void main()\n"
	"{\n"
	"    gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);\n"
	"}\n";

void compile_shader(GLuint shader, const char* source)
{
	glShaderSource(shader, 1, &source, 0);
	glCompileShader(shader);

	int err = glGetError();
	if(err)
	{
		log_info("gl error");
	}
}


ORCA_EXPORT void OnInit(void)
{
    surface = mg_surface_gles();

    mg_surface_prepare(surface);

	unsigned int vshader = glCreateShader(GL_VERTEX_SHADER);
	unsigned int fshader = glCreateShader(GL_FRAGMENT_SHADER);
	program = glCreateProgram();

	compile_shader(vshader, vshaderSource);
	compile_shader(fshader, fshaderSource);

	glAttachShader(program, vshader);
	glAttachShader(program, fshader);
	glLinkProgram(program);
	glUseProgram(program);
}

ORCA_EXPORT void OnFrameResize(u32 width, u32 height)
{
    log_info("frame resize %u, %u", width, height);
    frameSize.x = width;
    frameSize.y = height;
}

ORCA_EXPORT void OnFrameRefresh(void)
{
    f32 aspect = frameSize.x/frameSize.y;

    mg_surface_prepare(surface);

	glClearColor(0, 1, 1, 1);
	glClear(GL_COLOR_BUFFER_BIT);

 	static float alpha = 0;

	glViewport(0, 0, frameSize.x * 2, frameSize.y * 2);

    GLfloat matrix[] = {cosf(alpha)/aspect, sinf(alpha), 0, 0,
    	                   -sinf(alpha)/aspect, cosf(alpha), 0, 0,
    	                   0, 0, 1, 0,
    	                   0, 0, 0, 1};
    alpha += 2*M_PI/120;

    glUniformMatrix4fv(0, 1, false, matrix);

	GLfloat vertices[] = {
		-0.866/2, -0.5/2, 0, 0.866/2, -0.5/2, 0, 0, 0.5, 0};

    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, vertices);
    glEnableVertexAttribArray(0);
    glDrawArrays(GL_TRIANGLES, 0, 3);

    mg_surface_present(surface);
}