//
//  Game.m
//  iOSGLEssentials
//
//  Created by Joshua Moerman on 08/03/14.
//
//

#import "Game.h"
#include <moggle/core/gl.hpp>

#define BUFFER_OFFSET(i) ((char *)NULL + (i))


#ifdef TARGET_OS_IPHONE
NSString * file = @"Fractal-iOS";
#else
NSString * file = @"Fractal";
#endif

const GLfloat quad[] = {
    // x y z, r g b
    1, -1, 0, 1, 0, 0,
    -1, -1, 0, 0, 1, 0,
    1, 1, 0, 0, 0, 1,
    -1, 1, 0, 1, 1, 1
};

static void check_shader(GLuint s){
    GLint logLength;
    glGetShaderiv(s, GL_INFO_LOG_LENGTH, &logLength);
    if (logLength > 0) {
        GLchar *log = (GLchar *)malloc(logLength);
        glGetShaderInfoLog(s, logLength, &logLength, log);
        NSLog(@"Shader compile log:\n%s", log);
        free(log);
    }
}

@implementation Game{
    float time;
    GLuint program;
    GLint uniform;
    GLuint vao;
    GLuint posBufferName;
}

- (id)init{
    if(self = [super init]){
        time = 0;
        program = glCreateProgram();
        
        NSError * error = nil;
        
        NSString * vs = [NSString stringWithContentsOfFile:[[NSBundle mainBundle] pathForResource:file ofType:@"vsh"] encoding:NSASCIIStringEncoding error:&error];
        NSString * fs = [NSString stringWithContentsOfFile:[[NSBundle mainBundle] pathForResource:file ofType:@"fsh"] encoding:NSASCIIStringEncoding error:nil];
        
        GLchar const * vs_cstr = [vs UTF8String];
        GLchar const * fs_cstr = [fs UTF8String];
        
        GLuint v = glCreateShader(GL_VERTEX_SHADER);
        glShaderSource(v, 1, &vs_cstr, NULL);
        glCompileShader(v);
        check_shader(v);
        
        GLuint f = glCreateShader(GL_FRAGMENT_SHADER);
        glShaderSource(f, 1, &fs_cstr, NULL);
        glCompileShader(f);
        check_shader(f);

        glAttachShader(program, v);
        glAttachShader(program, f);
        
        glBindAttribLocation(program, 0, "position");
        glBindAttribLocation(program, 1, "color");
        
        glLinkProgram(program);
        
        uniform = glGetUniformLocation(program, "rotation");
        
        glDetachShader(program, v);
        glDeleteShader(v);
        glDetachShader(program, f);
        glDeleteShader(f);
        
        glGenVertexArrays(1, &vao);
        glBindVertexArray(vao);
        
		glGenBuffers(1, &posBufferName);
		glBindBuffer(GL_ARRAY_BUFFER, posBufferName);
        glBufferData(GL_ARRAY_BUFFER, 4*6*4, quad, GL_STATIC_DRAW);

        glEnableVertexAttribArray(0);
        glEnableVertexAttribArray(1);

        glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6*4, BUFFER_OFFSET(0));
        glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6*4, BUFFER_OFFSET(3*4));
    }
    return self;
}

- (void)update:(float)dt{
    time += dt;
}

- (void)draw{
    glClearColor(0.65f, 0.65f, 0.65f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    
    glUseProgram(program);
    glUniform1f(uniform, time);
    glBindVertexArray(vao);
    
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
}

@end