// Copyright (C) 2010, Guy Barrand. All rights reserved.
// See the file tools.license for terms.

#ifndef tools_sg_base_camera
#define tools_sg_base_camera

#include "node"

#include "sf_vec3f"
#include "sf_vec4f"
#include "sf_rotf"

#include "render_action"
#include "pick_action"
#include "event_action"
#include "visible_action"
#include "enums"

#include "../mathf" //astro

namespace tools {
namespace sg {

class base_camera : public node {
  TOOLS_HEADER(base_camera,tools::sg::base_camera,node)
public:
  sf<float> znear;
  sf<float> zfar;
  sf_vec3f position;
  //Camera orientation specified as a rotation value from the default
  //orientation where the camera is pointing along the negative z-axis,
  //with "up" along the positive y-axis.
  sf_rotf orientation;

  //for viewers :
  sf<float> dx;
  sf<float> da;
  sf<float> ds;
  sf<float> focal;
public:
  virtual const std::vector<field_desc>& node_fields() const {
    TOOLS_FIELD_DESC_NODE_CLASS(tools::sg::base_camera)
    static std::vector<field_desc> s_v;
    if(s_v.empty()) {
      s_v = parent::node_fields();
      TOOLS_ADD_FIELD_DESC(znear)
      TOOLS_ADD_FIELD_DESC(zfar)
      TOOLS_ADD_FIELD_DESC(position)
      TOOLS_ADD_FIELD_DESC(orientation)
      TOOLS_ADD_FIELD_DESC(dx)
      TOOLS_ADD_FIELD_DESC(da)
      TOOLS_ADD_FIELD_DESC(ds)
      TOOLS_ADD_FIELD_DESC(focal)
    }
    return s_v;
  }
private:
  void add_fields(){
    add_field(&znear);
    add_field(&zfar);
    add_field(&position);
    add_field(&orientation);

    add_field(&dx);
    add_field(&da);
    add_field(&ds);
    add_field(&focal);
  }
public:
  virtual float near_height() const = 0;
  virtual void zoom(float) = 0;
  virtual camera_type type() const = 0;
  virtual void get_lrbt(unsigned int,unsigned int,
                        float&,float&,float&,float&) = 0;
public:
  virtual void render(render_action& a_action) {
    _mult_matrix(a_action);
    set_state(a_action);
    a_action.load_proj_matrix(a_action.projection_matrix());
    a_action.load_model_matrix(a_action.model_matrix());
  }
  virtual void pick(pick_action& a_action) {
    _mult_matrix(a_action);
    set_state(a_action);
  }
  virtual void event(event_action& a_action){
    _mult_matrix(a_action);
    set_state(a_action);
  }
  virtual void get_matrix(get_matrix_action& a_action){
    _mult_matrix(a_action);
    set_state(a_action);
  }
  virtual void is_visible(visible_action& a_action){
    _mult_matrix(a_action);
    set_state(a_action);
  }
protected:
  base_camera()
  :parent()
  ,znear(1)
  ,zfar(10)
  ,position(vec3f(0,0,1))
  ,orientation(rotf(vec3f(0,0,1),0)) //quat = vec4f(0,0,0,1)
  ,dx(0.01f)
  ,da(0.017f) //one degree.
  ,ds(0.99f)
  ,focal(1)
  {
#ifdef TOOLS_MEM
    mem::increment(s_class().c_str());
#endif
    add_fields();
  }
public:
  virtual ~base_camera(){
#ifdef TOOLS_MEM
    mem::decrement(s_class().c_str());
#endif
  }
protected:
  base_camera(const base_camera& a_from)
  :parent(a_from)
  ,znear(a_from.znear)
  ,zfar(a_from.zfar)
  ,position(a_from.position)
  ,orientation(a_from.orientation)
  ,dx(a_from.dx)
  ,da(a_from.da)
  ,ds(a_from.ds)
  ,focal(a_from.focal)
  {
#ifdef TOOLS_MEM
    mem::increment(s_class().c_str());
#endif
    add_fields();
  }
  base_camera& operator=(const base_camera& a_from){
    parent::operator=(a_from);
    znear = a_from.znear;
    zfar = a_from.zfar;
    position = a_from.position;
    orientation = a_from.orientation;
    dx = a_from.dx;
    da = a_from.da;
    ds = a_from.ds;
    focal = a_from.focal;
    m_lrbt.set_value(0,0,0,0);
    return *this;
  }
protected: //operators:
  bool operator==(const base_camera& a_from) const{
    if(znear!=a_from.znear) return false;
    if(zfar!=a_from.zfar) return false;
    if(position!=a_from.position) return false;
    if(orientation!=a_from.orientation) return false;
    //we do not test dx,da,ds.
    return true;
  }
  //bool operator!=(const base_camera& a_from) const {
  //  return !operator==(a_from);
  //}
public:
  void direction(vec3f& a_dir) const {
    orientation.value().mul_vec(vec3f(0,0,-1),a_dir);
  }

  void rotate_around_direction(float a_delta) { //used in exlib/examples/iOS/sg.
    vec3f dir;
    orientation.value().mul_vec(vec3f(0,0,-1),dir);
    //_MSC_VER : does not compile : orientation = rotf(dir,a_delta) * orientation;
    orientation.value(rotf(dir,a_delta) * orientation.value());
  }

  void rotate_around_up(float a_delta){
    vec3f up;
    orientation.value().mul_vec(vec3f(0,1,0),up);
  //orientation.value(rotf(up,a_delta) * orientation.value());
    // must be the below so that rot-cam works for exlib/cbk/[pyrfits,astro,cfitsio] astro setup.
    // (astro setup change camera orientation).
    orientation.value(orientation.value() * rotf(up,a_delta));
  }

  void rotate_around_y_at_focal(float a_delta){
    //from coin SoGuiExaminerViewerP::rotYWheelMotion.
    vec3f dir;
    orientation.value().mul_vec(vec3f(0,0,-1),dir);
    vec3f focalpoint = position.value() + focal * dir;
    orientation.value(rotf(vec3f(0,1,0),a_delta) * orientation.value());
    orientation.value().mul_vec(vec3f(0,0,-1),dir);
    position = focalpoint - focal * dir;
  }

  void rotate_around_x_at_focal(float a_delta){
    //from coin SoGuiExaminerViewerP::rotXWheelMotion.
    vec3f dir;
    orientation.value().mul_vec(vec3f(0,0,-1),dir);
    vec3f focalpoint = position.value() + focal * dir;
    orientation.value(rotf(vec3f(1,0,0),a_delta) * orientation.value());
    orientation.value().mul_vec(vec3f(0,0,-1),dir);
    position = focalpoint - focal * dir;
  }

  void rotate_to_dir(const vec3f& a_dir) {
    //rotate around up so that a_dir is in (dir,up) plane 

    //NOTE : it is the invert of orientation which is used
    //       in projection matrix.

   {vec3f dir;
    orientation.value().mul_vec(vec3f(0,0,-1),dir);
    vec3f up;
    orientation.value().mul_vec(vec3f(0,1,0),up);
    vec3f side;dir.cross(up,side);
    vec3f v = side * (side.dot(a_dir)) + dir * (dir.dot(a_dir));    
    if(v.normalize()) orientation.value(orientation.value()*rotf(dir,v));}

    //rotate around dir^up so that a_dir matches dir.
   {vec3f dir;
    orientation.value().mul_vec(vec3f(0,0,-1),dir);
    orientation.value(orientation.value()*rotf(dir,a_dir));}

/*
    //check that dir is on a_dir :
   {vec3f dir;
    orientation.value().mul_vec(vec3f(0,0,-1),dir); 
    float cos_angle; //it should be 1
    if(!dir.cos_angle(a_dir,cos_angle)) {
      ::printf("debug : can't get angle\n");
      return;
    }
    ::printf("debug : cos_angle %g\n",cos_angle);}
*/
  }

  void pane_to(float a_x,float a_y,float a_z){
    //translate in view plane so that (a_x,a_y,a_z) is on direction.

    vec3f dir;
    orientation.value().mul_vec(vec3f(0,0,-1),dir);
    vec3f up;
    orientation.value().mul_vec(vec3f(0,1,0),up);
    vec3f side;dir.cross(up,side);

    vec3f d(a_x,a_y,a_z);
    d.subtract(position.value());

    vec3f pos = position.value() + side * (side.dot(d)) + up * (up.dot(d));
    position.value(pos);
  }

  void translate_along_side(float a_delta){
    vec3f dir;
    orientation.value().mul_vec(vec3f(0,0,-1),dir);
    vec3f up;
    orientation.value().mul_vec(vec3f(0,1,0),up);
    vec3f side;dir.cross(up,side);
    vec3f pos = position.value() + side * a_delta;
    position.value(pos);
  }
  void translate_along_up(float a_delta){
    vec3f dir;
    orientation.value().mul_vec(vec3f(0,0,-1),dir);
    vec3f up;
    orientation.value().mul_vec(vec3f(0,1,0),up);
    vec3f pos = position.value() + up * a_delta;
    position.value(pos);
  }
  void translate_along_dir(float a_delta){
    vec3f dir;
    orientation.value().mul_vec(vec3f(0,0,-1),dir);
    vec3f pos = position.value() + dir * a_delta;
    position.value(pos);
  }

  //NOTE : print is a Python keyword.
  void dump(std::ostream& a_out) {
    a_out << " znear " << znear.value() << std::endl;
    a_out << " zfar " << zfar.value() << std::endl;
    vec3f& pos = position.value();
    a_out << " pos " << pos[0] << " " << pos[1] << " " << pos[2] << std::endl;
    //FIXME : dump orientation.
  }

  bool is_type_ortho() const {return type()==camera_ortho?true:false;}

  bool height_at_focal(float& a_h) const {
    if(is_type_ortho()) {
      a_h = near_height();
    } else {
      if(!znear.value()) {a_h = near_height();return false;}
      a_h = focal.value()*near_height()/znear.value();
    }
    return true;
  }

  void astro_orientation(float a_ra,float a_dec/*,const vec3f&  a_center*/) {
    // a_ra, a_dec are in decimal degrees.

    // Camera default point toward -z with up along +y and +x at right.

    // Arrange so that camera points toward x with up along +z :
    rotf r(vec3f::s_y(),-fhalf_pi());
    r *= rotf(vec3f::s_x(),fhalf_pi());    
    // Now -y is at right.

    // Then rotate it so that it points toward given (ra,dec) by keeping up upward +z direction.
    r *= rotf(vec3f::s_y(),-a_dec*fdeg2rad());
    r *= rotf(vec3f::s_z(),a_ra*fdeg2rad());
    orientation = r;

/*
    position = a_center*0.99f;
    znear = 0.1f;
    zfar = 200.0f;
    focal = (a_center-position).length();
*/
/*
    position = vec3f(0,0,0);
    znear = 1.0f;
    zfar = 2000.0f; //2*sky_radius.
    focal = a_center.length();
    da = 0.017f/100; //1/100 of a degree
*/
  }
protected:
  void update_sg(std::ostream& a_out) {

   {const vec4f& v = m_lrbt.value();
    float l = v[0];
    float r = v[1];
    float b = v[2];
    float t = v[3];
    float n = znear.value();
    float f = zfar.value();
    if(is_type_ortho()) {
      m_proj.set_ortho(l,r,b,t,n,f);
    } else {
      m_proj.set_frustum(l,r,b,t,n,f);
    }}

    if(orientation.value().quat()!=id_orientation()) //OPTIMIZATION
   {rotf rinv;
    if(orientation.value().inverse(rinv)) {
      mat4f mtx;
      rinv.value(mtx);
      m_proj.mul_mtx(mtx,m_tmp);
    } else {
      a_out << "base_camera::update_sg :"
            << " get orientation inverse failed."
            << std::endl;
    }}

    m_proj.mul_translate(-position.value()[0],
                         -position.value()[1],
                         -position.value()[2]);
  }

  void _mult_matrix(matrix_action& a_action) {
    float l,r,b,t;
    get_lrbt(a_action.ww(),a_action.wh(),l,r,b,t);
    m_lrbt.set_value(l,r,b,t);

    if(touched()||m_lrbt.touched()) {
      update_sg(a_action.out());
      reset_touched();
      m_lrbt.reset_touched(); 
    }
    
    a_action.projection_matrix().mul_mtx(m_proj,m_tmp);
  }

  void set_state(matrix_action& a_action) {
    state& _state = a_action.state();
    _state.m_camera_ortho = is_type_ortho();
    _state.m_camera_znear = znear;
    _state.m_camera_zfar = zfar;
    _state.m_camera_position = position.value();
    _state.m_camera_orientation = orientation.value();
    //_state.m_camera_near_height = near_height();
    _state.m_camera_lrbt = m_lrbt.value();
    _state.m_proj = a_action.projection_matrix();
  }

  static const vec4<float>& id_orientation() {
    static const vec4<float> s_v(0,0,0,1,false);
    return s_v;
  }

protected:
  //OPTIMIZATION :
  sf_vec4f m_lrbt;
  mat4f m_proj;
  float m_tmp[16];
};

}}

#endif