#include <iostream>
#include <vector>
#include <cmath>

#include "Angel.h"
#include <GL/glew.h>
#include "keys.h"

using namespace std;

// globals
vector<vec3> data;
vector<vec3> colors;
GLuint  loc[2];
GLenum DRAWING_MODE;

// Constants
const int POINTS = 60;

vec3 Color(float theta) {
    vec3 tmpColor;

	if(theta < M_PI/2.0) {
	     tmpColor[0] = 1.0;
	     tmpColor[1] = theta/(M_PI/2.0);
	     tmpColor[2] = 0;
	} else if (theta < M_PI) {
	     tmpColor[0] = theta/(M_PI/2.0) - 1.0;
	     tmpColor[1] = 1.0;
	     tmpColor[2] = 0;
	} else if (theta < 1.5*M_PI) {
	     tmpColor[0] = 0;
	     tmpColor[1] = theta/(M_PI/2.0) - 2;
	     tmpColor[2] = 1.0;
	} else {
	     tmpColor[0] = 4- theta/(M_PI/2.0) ;
	     tmpColor[1] = theta/(M_PI/2.0) - 3;
	     tmpColor[2] = 1.0;
	}
    return tmpColor;
}

void Init(void) {
    vec3 tmp;
    vec3 tmpColor;
    float theta;
   
    srand(time(NULL));

    // background clear color
    glClearColor(1.0,1.0,1.0,1.0);

    // I want to be able to see what is happening with polygons
    glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);

    // generate the data on a circle
    for( theta=0;theta<2*M_PI;theta+= 2*M_PI/POINTS) {
        tmp.x = .75*cos(theta);
        tmp.y = .75*sin(theta);
	tmp.z = 0;
        data.push_back(tmp);
	data.push_back(Color(theta));
    }

    // a default mode for drawing things
    DRAWING_MODE = GL_POINTS;
    glEnable(GL_PROGRAM_POINT_SIZE); 

    // first we need to load shaders
    GLuint program = InitShader( "vshader2.glsl", "fshader2.glsl" );
    
    // now a vertex array object
    GLuint vao;
    glGenVertexArrays( 1, &vao );
    glBindVertexArray( vao);

    // now  a buffer to hold our data.
    GLuint buffer[1];
    glGenBuffers(1, buffer);
    glBindBuffer(GL_ARRAY_BUFFER, buffer[0]);
    glBufferData(GL_ARRAY_BUFFER, data.size() * sizeof(vec3)
                                , data.data() , GL_STATIC_DRAW);

    loc[0] = glGetAttribLocation( program, "vPosition" );
    glVertexAttribPointer(loc[0],3,GL_FLOAT, GL_FALSE,2*3*sizeof(GLfloat) 
              , BUFFER_OFFSET(0));

    loc[1] = glGetAttribLocation( program, "vColor" );
    glEnableVertexAttribArray( loc[1] );
    glVertexAttribPointer(loc[1],3,GL_FLOAT, GL_FALSE, 2*3*sizeof(GLfloat),
                             BUFFER_OFFSET(sizeof(vec3)));


    return;
}

void display(void) {

    glClear( GL_COLOR_BUFFER_BIT );
    glEnableVertexAttribArray( loc[0] );
    glEnableVertexAttribArray( loc[1] );
    glDrawArrays(DRAWING_MODE, 0, data.size()/2);
    glutSwapBuffers();

    return;
}

int main( int argc, char **argv ) {
    glutInit( &argc, argv );
    glutInitDisplayMode( GLUT_RGBA | GLUT_DOUBLE );
    glutInitWindowSize( 512, 512 );

    glutCreateWindow( "Primitive Modes, New Code" );

    GLenum err = glewInit();
    if (GLEW_OK != err) {
        cout << "glewInit failed, aborting." << endl;
        exit (1);
    }

    Init();

    glutDisplayFunc(display);
    glutKeyboardFunc(keyboard);

    glutMainLoop();
    return 0;
}