#include <iostream>
#include <vgl.h>

#include "CameraClass.h"

using namespace std;

void CameraClass::Reset() {
    eye  =      vec4(0.0, 3.0, -10.0, 1.0);
    lookAt =   vec4(0.0, 0.0, 0.0, 1.0);
    up =        vec4(0.0, 1.0, 0.0, 1.0);

    Look_Ahead =   10.0;
    Step_Size  =    0.5;
    Travel_Angle = 90.0;

    RepositionCenter();

    return;
}

CameraClass::CameraClass(){
   Reset();
}

void CameraClass::Display(GLuint matrixLocation){
   mat4 world;

   world = LookAt(eye, lookAt, up);
   glUniformMatrix4fv(matrixLocation,1, GL_TRUE, world);

   return;
}

bool CameraClass::Keypress(unsigned char key) {

    switch(key) {
       case 'A':
          Look_Ahead += Step_Size;
          if (Look_Ahead > 15) {
              Look_Ahead = 15;
          }
          RepositionCenter();
	  return true;
       case 'a':
          Look_Ahead -= Step_Size;
          if (Look_Ahead < 3) {
              Look_Ahead = 3;
          }
          RepositionCenter();
	  return true;
       case 'c':
          lookAt.y -= .5;
          RepositionCenter();
	  return true;
       case 'C':
          lookAt.y += .5;
          RepositionCenter();
	  return true;
       case 'u':
          eye.y += 1;
	  return true;
       case 'd':
          eye.y -= 1;
	  return true;
    }
    return false;
}

void CameraClass::Usage() {
    cout << endl;
    cout << "\t\tCamera Options" << endl;
    cout << "\tA/a\t" << "Change Look Ahead" << endl;
    cout << "\tC/c\t" << "Change lookAt Y" << endl;
    cout << "\tu\t"   << "Move up" << endl;
    cout << "\td\t"   << "Move Down" << endl;
    cout << endl;
    return;
}

void CameraClass::RepositionCenter() {
    GLfloat dx, dz;

    while (Travel_Angle < 0) {
        Travel_Angle += 360;
    }

    while (Travel_Angle > 360) {
        Travel_Angle -= 360;
    }

    dx = Look_Ahead * cos(Travel_Angle*M_PI/180.0);
    dz = Look_Ahead * sin(Travel_Angle*M_PI/180.0);

    lookAt.x = eye.x + dx;
    lookAt.z = eye.z + dz;

    return;
}


// dir is the direction of the move 1, forward, -1 backward

void CameraClass::Move(int dir) {
    GLfloat dx, dz;

    dx =  dir*Step_Size * cos(Travel_Angle*M_PI/180.0);
    dz =  dir*Step_Size * sin(Travel_Angle*M_PI/180.0);

    eye.x += dx;
    eye.z += dz;
    lookAt.x += dx;
    lookAt.z += dz;

    return;
}

bool CameraClass::SpecialKeypress(int key) {
      switch (key) {
       case GLUT_KEY_UP:
            Move(1);
            return true;
       case GLUT_KEY_DOWN:
            Move(-1);
            return true;
       case GLUT_KEY_LEFT:
             Travel_Angle -= 5;
             RepositionCenter();
            return true;
       case GLUT_KEY_RIGHT:
             Travel_Angle += 5;
             RepositionCenter();
            return true;
    }
    return false;
}

vec3 CameraClass::Eye() {
    return vec3(eye.x, eye.y, eye.z);
}