#include <GL/glut.h>
#include <math.h>
#include <stdio.h>
#include <stdbool.h>
#include <string.h>

//------------------
//  VARIABLES
//------------------

//angle of rotation for camera direction
float angle = 0.0f;

//the key states, these variables will be 0
//when no key is being pressed
float deltaAngle = 0.0f;
float deltaMove = 0;
int xOrigin = -1;

//XZ position of camera
float x = 0.0f, z = 5.0f;

//actual vector representing the cameras direction
float lx = 0.0f, lz = -1.0f;

float red = 1.0f;
float blue = 0.5f;
float green = 0.5f;

//load textures
GLuint tableTopTexture;
GLuint tableLegTexture;

//------------------
//  TEXTURES
//------------------

GLuint LoadTexture(const char * filename){
    GLuint texture;

    int width, height;

    unsigned char * data;

    FILE * file;

    file = fopen(filename, "rb");

    if(file == NULL)
        return 0;
    width = 512;
    height = 1024;
    data = (unsigned char *) malloc (width * height * 3);

    fread(data, width * height * 3, 1, file);
    fclose(file);

    for(int i = 0; i < width * height; ++i){
        int index = i * 3;
        unsigned char B,R;
        B = data[index];
        R = data[index + 2];

        data[index] = R;
        data[index + 2] = B;
    }

    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);

    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    gluBuild2DMipmaps(GL_TEXTURE_2D, 3,width, height, GL_RGB, GL_UNSIGNED_BYTE, data);

    return texture;
}

void loadTextures(){
    tableTopTexture = LoadTexture("table_top.bmp");
    tableLegTexture = LoadTexture("table_leg.bmp");
}

//------------------
//  DRAWING
//------------------

void drawCube(float scale_x, float scale_y, float scale_z, float position_x, float position_y, float position_z) {

    glPushMatrix();
        glTranslatef(position_x,position_y,position_z);
        glScalef(scale_x,scale_y,scale_z);
        glBegin(GL_QUADS);
            //top face
            glColor3f(0,green,0);
            glVertex3f(1.0,1.0,-1.0);
            glVertex3f(-1.0,1.0,-1.0);
            glVertex3f(-1.0,1.0,1.0);
            glVertex3f(1.0,1.0,1.0);

            //bottom face
            glColor3f(1.0f,0.5f,0.0f);
            glVertex3f(1.0,1.0,1.0);
            glVertex3f(-1.0,1.0,1.0);
            glVertex3f(-1.0,-1.0,1.0);
            glVertex3f(1.0,-1.0,1.0);

            //front face
            glColor3f(1.0f,0.0f,0.0f);
            glVertex3f(1.0,1.0,1.0);
            glVertex3f(-1.0,1.0,1.0);
            glVertex3f(-1.0,-1.0,1.0);
            glVertex3f(1.0,-1.0,1.0);

            //back face
            glColor3f(1.0f,1.0f,0.0f);
            glVertex3f(1.0,-1.0,-1.0);
            glVertex3f(-1.0,-1.0,-1.0);
            glVertex3f(-1.0,1.0,-1.0);
            glVertex3f(1.0,1.0,-1.0);

            //left face
            glColor3f(0.0f,0.0f,1.0f);
            glVertex3f(-1.0,1.0,1.0);
            glVertex3f(-1.0,1.0,-1.0);
            glVertex3f(-1.0,-1.0,-1.0);
            glVertex3f(-1.0,-1.0,1.0);

            //right
            glColor3f(1.0f,0.0f,1.0f);
            glVertex3f(1.0,1.0,-1.0);
            glVertex3f(1.0,1.0,1.0);
            glVertex3f(1.0,-1.0,1.0);
            glVertex3f(1.0,-1.0,-1.0);
        glEnd();
    glPopMatrix();
}

void drawTable(){

    //texture stuff
    glEnable(GL_TEXTURE_2D);
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);



    //draw legs
    glBindTexture(GL_TEXTURE_2D, tableLegTexture);
    glTexCoord2f(0.0,0.0);
    drawCube(0.050,0.5,0.060,0,0,0);
    glTexCoord2f(0.0,1.0);
    drawCube(0.050,0.5,0.060,3,0,0);
    glTexCoord2f(1.0,1.0);
    drawCube(0.050,0.5,0.060,3,0,-1);
    glTexCoord2f(1.0,0.0);
    drawCube(0.050,0.5,0.060,0,0,-1);

    //draw table top
    glBindTexture(GL_TEXTURE_2D, tableTopTexture);
    glTexCoord2f(0.0,0.0);
    glTexCoord2f(1.0,0.0);
    glTexCoord2f(1.0,1.0);
    glTexCoord2f(0.0,1.0);
    drawCube(2,0.050,1,1.5,0.5,-0.5);

    glDisable(GL_TEXTURE_2D);
}

void drawLight(){
    //draw base
    drawCube(0.30,0.02,0.30,0,0,0);

    //draw center pole
    drawCube(0.02,1,0.02,0,1,0);

    //draw light
    drawCube(0.04,0.50,0.04,0,1.3,0);

    //draw shade
    drawCube(0.20,0.65,0.005,0,1.3,-0.10);
    drawCube(0.005,0.65,0.10,0.20,1.3,0);
    drawCube(0.005,0.65,0.10,-0.20,1.3,0);
    drawCube(0.20,0.65,0.005,0,1.3,0.10);
}

void drawChair(){
    //draw legs
    drawCube(0.025,0.70,0.020,0,0.35,0);
    drawCube(0.025,0.35,0.019,0.50,0,0);
    drawCube(0.025,0.70,0.020,0,0.35,-0.45);
    drawCube(0.025,0.35,0.019,0.50,0,-0.45);

    //draw seat
    drawCube(0.27,0.02,0.26,0.27,0.33,-0.22);

    //draw back support
    drawCube(0.025,0.030,0.21,0,1,-0.22);
    drawCube(0.025,0.030,0.21,0,0.75,-0.22);
}

void drawWalls(){
    glColor3f(1,0,0);
    glPushMatrix();
    glBegin(GL_QUADS);
        //floor
        glVertex3f(-1,-1,-1);
        glVertex3f(1,-1,-1);
        glVertex3f(1,-1,1);
        glVertex3f(-1,-1,1);

        //ceiling
        glVertex3f(-1,1,-1);
        glVertex3f(1,1,-1);
        glVertex3f(1,1,1);
        glVertex3f(-1,1,1);

        glColor3f(0,1,0);

        //walls
        glVertex3f(-1,-1,1);
        glVertex3f(1,-1,1);
        glVertex3f(1,1,1);
        glVertex3f(-1,1,1);

        glVertex3f(-1,-1,-1);
        glVertex3f(1,-1,-1);
        glVertex3f(1,1,-1);
        glVertex3f(-1,1,-1);

        glVertex3f(1,1,1);
        glVertex3f(1,-1,1);
        glVertex3f(1,-1,-1);
        glVertex3f(1,1,-1);

        glVertex3f(-1,1,1);
        glVertex3f(-1,-1,1);
        glVertex3f(-1,-1,-1);
        glVertex3f(-1,1,-1);
    glEnd();
    glPopMatrix();
}

//------------------
//  MOUSE
//------------------
void mouseButton(int button, int state, int x, int y){
    //only start motion if the left button is pressed
    if(button == GLUT_LEFT_BUTTON) {
        angle += deltaAngle;
        xOrigin = -1;
    }
    else {
        xOrigin = x;
    }
}

void mouseMove(int x, int y){
    //this will only be true when the left button is down
    if(xOrigin >= 0){
        //update deltaAngle
        deltaAngle = (x - xOrigin) * 0.001f;

        //update cameras direction
        lx = sin(angle + deltaAngle);
        lz = -cos(angle + deltaAngle);
    }
}

void computePos(float deltaMove){
    x += deltaMove * lx * 0.1f;
    z += deltaMove * lz * 0.1f;
}

void computeDir(float deltaAngle){
    angle += deltaAngle;
    lx = sin(angle);
    lz = -cos(angle);
}


//------------------
//  KEYBOARD
//------------------

void pressKey(int key, int xx, int yy){
    switch(key){
        case GLUT_KEY_LEFT :
            deltaAngle = -0.01f;
            break;
        case GLUT_KEY_RIGHT :
            deltaAngle = 0.01f;
            break;
        case GLUT_KEY_UP :
            deltaMove = 0.5f;
            break;
        case GLUT_KEY_DOWN :
            deltaMove = -0.5f;
            break;
    }
}

void releaseKey(int key, int x, int y){
    switch(key){
        case GLUT_KEY_LEFT :
        case GLUT_KEY_RIGHT :
            deltaAngle = 0.0f;
            break;
        case GLUT_KEY_UP :
        case GLUT_KEY_DOWN :
            deltaMove = 0;
            break;
    }
}

//------------------
//  RENDERING
//------------------
void renderScene(void){

    if(deltaMove)
        computePos(deltaMove);
    if(deltaAngle)
        computeDir(deltaAngle);

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();

    gluLookAt(
        x,1.0f,z,
        x+lx,1.0f, z+lz,
        0.0f,1.0f,0.0f
    );

    //drawLight();

    //add table to scene

    glPushMatrix();
        glTranslatef(0,0,0);
        drawTable();
    glPopMatrix();
    //add chairs to scene
    //glPushMatrix();
    //  glTranslatef(1,0,1);
    //  glRotatef(90,0,1,0);
    //  drawChair();
    //glPopMatrix();

    //glPushMatrix();
    //  glTranslatef(2.5,0,1);
    //  glRotatef(90,0,1,0);
    //  drawChair();
    //glPopMatrix();

    //glPushMatrix();
    //  glTranslatef(1,0,-2);
    //  glRotatef(270,0,1,0);
    //  drawChair();
    //glPopMatrix();

    //glPushMatrix();
    //  glTranslatef(2.5,0,-2);
    //  glRotatef(270,0,1,0);
    //  drawChair();
    //glPopMatrix();

    glutSwapBuffers();
}


void changeSize(int w, int h){
    //prevent divide by 0 when window is too short
    if(h == 0)
        h==1;
    float ratio = 1.0 * w/h;

    //Use projection matrix
    glMatrixMode(GL_PROJECTION);

    //reset matrix
    glLoadIdentity();

    //set viewport to be entire window
    glViewport(0,0,w,h);

    gluPerspective(100,ratio,0.01,500);

    //get back to model view
    glMatrixMode(GL_MODELVIEW);
}

//------------------
//  MAIN
//------------------
int main (int argc, char **argv){

    //init glut and create window

    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
    glutInitWindowPosition(100,100);
    glutInitWindowSize(800,600);
    glutCreateWindow("Assignment 1");

    //register callbacks
    loadTextures();
    glutDisplayFunc(renderScene);
    glutReshapeFunc(changeSize);
    glutIdleFunc(renderScene);

    glutIgnoreKeyRepeat(1);
    glutSpecialFunc(pressKey);
    glutSpecialUpFunc(releaseKey);

    //mouse functions
    glutMouseFunc(mouseButton);
    glutMotionFunc(mouseMove);

    //OpenGL init
    glEnable(GL_DEPTH_TEST);

    //enter GLUT event processing cycle
    glutMainLoop();

    return 1;
}