//
//  main.cpp
//  XcodeOpenCL
//
//  Created by Joshua Moerman on 28/03/14.
//
//

#include "cl2.hpp"

#include "NSWrapper.hpp"
#include "../../CodeTA/ImageStreams/include/png.hpp"

#include <OpenGL/gl3.h>

#include <vector>
#include <iostream>
#include <fstream>
#include <sstream>
#include <cassert>
#include <cmath>

using namespace std;

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

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);
        std::cout << "Shader compile log:\n%s" << log << std::endl;
        free(log);
    }
}

string slurp(string filename) {
    ifstream in(filename);
    stringstream sstr;
    sstr << in.rdbuf();
    return sstr.str();
}

struct App {
    float time;
    GLuint program;
    GLint uniform;
    GLuint vao;
    GLuint posBufferName;
    
    void initialize(){
        time = 0;
        program = glCreateProgram();
        
        auto v_source_str = slurp("Fractal.vsh");
        auto v_source = v_source_str.c_str();
        GLuint v = glCreateShader(GL_VERTEX_SHADER);
        glShaderSource(v, 1, &v_source, NULL);
        glCompileShader(v);
        check_shader(v);
        
        auto f_source_str = slurp("Fractal.fsh");
        auto f_source = f_source_str.c_str();
        GLuint f = glCreateShader(GL_FRAGMENT_SHADER);
        glShaderSource(f, 1, &f_source, 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));
    }
    
    void draw(){
        time += 1/60.0f;
        
        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);
    }
};


int main(){
    const bool mandelbrot = false;
    if(mandelbrot) {
        App a;
        
        NSAppWrapper app;
        
        app.create_window({
            [&](ContextParameters){
                a.initialize();
            },
            [&](ContextParameters){
                a.draw();
            },
            nullptr
        });
        
        app.run();
        return 0;
    }
    // else, this other weird thing
        
    auto context = cl::Context::getDefault();
    cout << context << endl;

    cl_int err = 0;
    // build the program
    auto KernelSource = slurp("Kernel.cl");
    cl::Program program(context, {KernelSource.c_str(), KernelSource.size()}, true, &err);
    check(err);
    cout << program << endl;
    
    // grab the kernel
    KernelOp kernel(program, "square", &err);
    check(err);
    
    // create a queue
    cl::CommandQueue queue(context, context.getInfo<CL_CONTEXT_DEVICES>().front());
    
    // make a lot of data
    constexpr size_t W = 1280 * 4;
    constexpr size_t H = 800  * 4;
    std::vector<cl_float> input_vector(W*H);
    
    for(int y = 0; y < H; ++y){
        for(int x = 0; x < W; ++x){
            input_vector[x + W*y] = 10 * ((x / double(W) - 0.5) + 1.3371337*(y / double(H) - 0.5));
        }
    }
    
    // transfer data into buffers
    cl::Buffer input(context, input_vector.begin(), input_vector.end(), false, true);
    
    int r = 80, g = 40, b = 20;
    
    // DO IT (in place)
    for(int i = 0; i < r; ++i){
        check(kernel(queue, W, H, input, W, input));
    }

    // read back
    queue.finish();
    
    auto red = input_vector;
    
    // DO IT (in place)
    for(int i = 0; i < g; ++i){
        check(kernel(queue, W, H, input, W, input));
    }
    
    // read back
    queue.finish();
    
    auto green = input_vector;
    
    // DO IT (in place)
    for(int i = 0; i < b; ++i){
        check(kernel(queue, W, H, input, W, input));
    }
    
    // read back
    queue.finish();
    
    auto& blue = input_vector;
    
    // test
    cout << "opencl is done" << endl;
    png::ostream<> image(W, H, "test.png");
    for(int i = 0; i < red.size(); ++i){
        image << png::ostream<>::pixel(blue[i], red[i], green[i]);
    }
    cout << "png is saved" << endl;
}