//---------------------------------------------------------------------
//
// Created by Jeffrey Ventrella for High Fidelity.
// Copyright (c) 2013 High Fidelity, Inc. All rights reserved.
//
//---------------------------------------------------------------------

#include <SharedUtil.h>
// #include "Log.h"

#include "Camera.h"

Camera::Camera() {
    _frustumNeedsReshape  = false;
	_mode			  = CAMERA_MODE_THIRD_PERSON;
	_tightness		      = 10.0; // default
	_fieldOfView          = 60.0; // default
	_nearClip             = 0.08; // default
	_farClip              = 50.0; // default
    _modeShift            = 0.0;
	_yaw                  = 0.0;
	_pitch			      = 0.0;
	_roll			      = 0.0;
	_upShift		      = 0.0;
	_rightShift		      = 0.0;
	_distance		      = 0.0;
	_idealYaw		      = 0.0;
	_targetPosition	      = glm::vec3( 0.0, 0.0, 0.0 );
	_position		      = glm::vec3( 0.0, 0.0, 0.0 );
	_idealPosition	      = glm::vec3( 0.0, 0.0, 0.0 );
	_orientation.setToIdentity();
}


void Camera::update( float deltaTime )  {

    // generate the ortho-normals for the orientation based on the Euler angles
    _orientation.setToIdentity();
    _orientation.yaw  ( _yaw   );
    _orientation.pitch( _pitch );
    _orientation.roll ( _roll  );
    
    if ( _mode == CAMERA_MODE_NULL ) {
        _modeShift = 0.0;
    } else {
        // use iterative forces to keep the camera at the desired position and angle
        updateFollowMode( deltaTime );
        
        if ( _modeShift < 1.0f ) {
            _modeShift += MODE_SHIFT_RATE * deltaTime;
            if ( _modeShift > 1.0f ) {
                _modeShift = 1.0f;
            }
        }
    }
}


// use iterative forces to keep the camera at the desired position and angle
void Camera::updateFollowMode( float deltaTime ) {        
    // derive t from tightness
    float t = _tightness * deltaTime;	
    if ( t > 1.0 ) {
        t = 1.0;
    }

    // update _yaw (before position!) 
    _yaw += ( _idealYaw - _yaw ) * t;
    _orientation.yaw  ( _yaw   );
            
    float radian = ( _yaw / 180.0 ) * PIE;

    // update _position
    //these need to be checked to make sure they correspond to the correct coordinate system.
    double x = _distance * -sin( radian );
    double z = _distance *  cos( radian );
    double y = _upShift; 
        
    _idealPosition  = _targetPosition + glm::vec3( x, y, z );
    //_idealPosition += _orientation.getRight() * _rightShift;
    //_idealPosition += _orientation.getUp   () * _upShift;
    
    // pull position towards ideal position
    _position += ( _idealPosition - _position ) * t; 
}


// call to find out if the view frustum needs to be reshaped
bool Camera::getFrustumNeedsReshape() {
    return _frustumNeedsReshape;
}

// call this after reshaping the view frustum
void Camera::setFrustumWasReshaped() {
    _frustumNeedsReshape = false;
}