/******************************************************************/
/* This file is part of the homework assignments for CSCI-427/527 */
/* at The College of William & Mary and authored by Pieter Peers. */
/* No part of this file, whether altered or in original form, can */
/* be distributed or used outside the context of CSCI-427/527     */
/* without consent of either the College of William & Mary or     */
/* Pieter Peers.                                                  */
/******************************************************************/
#include <cassert>

#include "errorMessage.h"
#include "random_number.h"

#include "sceneIO_core.h"
#include "sceneIO_basis.h"
#include "sceneIO_light.h"
#include "sceneIO_texture.h"
#include "sceneIO_material.h"
#include "sceneIO_geometry.h"

#include "spotLightsource.h"
#include "areaLightsource.h"
#include "pointLightsource.h"
#include "directionalLightsource.h"

#include "lightsourceGeometry.h"

static std::shared_ptr<const lightsource_base> importDirectionalLight(const XMLNode& node)
{
  // get properties
  vec3d direction = getVec3d(node, "direction", vec3d(0.0f, 0.0f, 1.0f));
  color power = getColor(node, "power", color(1.0f, 1.0f, 1.0f));
                                
  // Done.
  return std::shared_ptr<const lightsource_base>( new directionalLightsource( direction, power));
}


static std::shared_ptr<const lightsource_base> importPointLight(const XMLNode& node)
{
  // get properties
  vec3d position = getVec3d(node, "position", vec3d(0.0f, 0.0f, 0.0f));
  color power = getColor(node, "power", color(1.0f, 1.0f, 1.0f));
  vec3d attenuation = getVec3d(node, "attenuation", vec3d(0.0f, 0.0f, 1.0f));

  // Done
  return std::shared_ptr<const lightsource_base>( new pointLightsource(position, power, attenuation)); 
}


static std::shared_ptr<const lightsource_base> importSpotLight(const XMLNode& node)
{
  // Get properties
  vec3d position = getVec3d(node, "position", vec3d(0.0f, 0.0f, 0.0f));
  vec3d direction = getVec3d(node, "direction", vec3d(0.0f, 0.0f, 1.0f));
  float cutoff = getFloat(node, "cutoff", 30.0f);
  float sharpness = getFloat(node, "sharpness", 1.0f);
  color power = getColor(node, "power", color(1.0f, 1.0f, 1.0f));
  vec3d attenuation = getVec3d(node, "attenuation", vec3d(0.0f, 0.0f, 1.0f));

  // Done.
  return std::shared_ptr<const lightsource_base>(new spotLightsource( position, direction, cutoff, sharpness, power, attenuation ));
}


static std::shared_ptr<const lightsource_base> importAreaLight(const XMLNode& node, nodeCache<boundedPrimitive>& shape_cache, nodeCache<shader_base>& shader_cache, nodeCache<texture_base>& texture_cache, const std::string& rootDir)
{
  // get properties
  color power = getColor(node, "power", color(1.0f, 1.0f, 1.0f));
  vec3d attenuation = getVec3d(node, "attenuation", vec3d(0.0f, 0.0f, 1.0f));

  // node properties
  std::shared_ptr<const shader_base> reflectanceMaterial;
  std::shared_ptr<const boundedPrimitive> geometry;

  // get children
  for(XMLNode child = node.firstChild(); child.isValid(); child++)
  {
    std::string name = child.name();

    // general child nodes
    auto tempMat = importMaterial(child, shader_cache, texture_cache, rootDir);
    auto tempGeom = importGeometry(child, shape_cache, shader_cache, texture_cache, rootDir);

    // specific child nodes
    if(tempMat) reflectanceMaterial = tempMat;
    else if(tempGeom) geometry = tempGeom;
    else errorMessage("Unknown child-node in areaLightsource (%s).", name.c_str());
  }
  
  // produce warning if shader defined on the geometry
  if(geometry && geometry->hasShader() && !reflectanceMaterial)
    warningMessage("Any shader defined on the geometry are ignored in AreaLightsource. Define a reflectance material explicitely in AreaLightsource instead.");

  // Create
  // 1) light source
  // 2) light source geometry
  std::shared_ptr<const lightsource_base> ls( new areaLightsource(power, geometry, attenuation) );
  std::shared_ptr<boundedPrimitive> lsShape( new lightsourceGeometry(geometry, ls, reflectanceMaterial) );

  // Add lsShape to shape_cache
  char id[32]; sprintf(id, "lightgeometry-%u", random_int());
shape_cache.add(std::string(id), lsShape);

  // Done.
  return ls;
}


std::shared_ptr<const lightsource_base> importLight(const XMLNode& node, nodeCache<boundedPrimitive>& shape_cache, nodeCache<shader_base>& shader_cache, nodeCache<texture_base>& texture_cache, const std::string& rootDir)
{
  // sanity check
  assert(node.name() == "light");

  // get light source type
  std::string type = getString(node, "type", "directional");
 
  // create light source
  std::shared_ptr<const lightsource_base> ls;
  if(type == "directional") ls = importDirectionalLight(node);
  else if(type == "point") ls = importPointLight(node);
  else if(type == "spot") ls = importSpotLight(node);
  else if(type == "area") ls = importAreaLight(node, shape_cache, shader_cache, texture_cache, rootDir);
  else errorMessage("Unknown light source type (%s)", type.c_str());

  // Done.
  return ls;
}