/*
 * Copyright (c) 2009 Jice
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * The name of Jice may not be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY Jice ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL Jice BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include <vector>

// size of the heightmap
static constexpr auto HM_WIDTH = 400;
static constexpr auto HM_HEIGHT = 400;

// biome and climate list. based on Whittaker Biome Diagram
enum EClimate { ARCTIC_ALPINE, COLD, TEMPERATE, WARM, TROPICAL, NB_CLIMATES };

// grassland : might be either grassland, shrubland or woodland depending on the vegetation level
// savanna : might be either savanna or thorn forest depending on the vegetation level
enum EBiome {
  TUNDRA,
  COLD_DESERT,
  GRASSLAND,
  BOREAL_FOREST,
  TEMPERATE_FOREST,
  TROPICAL_MONTANE_FOREST,
  HOT_DESERT,
  SAVANNA,
  TROPICAL_DRY_FOREST,
  TROPICAL_EVERGREEN_FOREST,
  THORN_FOREST,
  NB_BIOMES
};

class WorldGenerator {
 public:
  // altitude->color map
  TCODColor mapGradient[256];
  // world height map (0.0 - 1.0)
  TCODHeightMap* hm;
  // height map without erosion
  TCODHeightMap* hm2;
  // complete world map (not shaded)
  TCODImage* worldmap;
  // temperature map (in °C)
  TCODHeightMap* temperature;
  // precipitation map (0.0 - 1.0)
  TCODHeightMap* precipitation;
  // biome map
  EBiome* biomeMap;

  void generate(TCODRandom* wRng);

  // getters
  int getWidth() const;
  int getHeight() const;
  float getAltitude(int x, int y) const;  // heightmap. between 0 and 1
  float getInterpolatedAltitude(float x, float y) const;
  float getSandHeight() const;
  bool isOnSea(float x, float y) const;
  float getCloudThickness(float x, float y) const;
  void getInterpolatedNormal(float x, float y, float n[3]) const;
  TCODColor getInterpolatedColor(float worldX, float worldY);
  float getInterpolatedIntensity(float worldX, float worldY);

  // update
  void updateClouds(float elapsedTime);
  void computeSunLight(const float lightDir[3]);

  // data
  float getRealAltitude(float x, float y) const;  // altitude in meters
  float getPrecipitations(float x, float y) const;  // in centimeter/m²/year
  float getTemperature(float x, float y) const;  // in °C
  EBiome getBiome(float x, float y) const;

  // map generators
  void saveBiomeMap(const char* filename = NULL);
  void saveAltitudeMap(const char* filename = NULL);
  void saveTemperatureMap(const char* filename = NULL);
  void savePrecipitationMap(const char* filename = NULL);

 protected:
  friend class RiverPathCbk;
  TCODNoise* noise;
  // cloud thickness
  float clouds[HM_WIDTH][HM_HEIGHT];
  float cloudDx;  // horizontal offset for smooth scrolling
  float cloudTotalDx;
  // world light intensity map (shadow map)
  float* worldint;
  typedef struct {
    float slope;
    // number of cells flowing into this cell
    uint32_t area;
    // direction of lowest neighbour
    uint8_t flowDir;
    // inverse flow direction
    uint8_t upDir;
    uint8_t inFlags;  // incoming flows
    uint8_t riverId;
    int riverLength;
  } map_data_t;
  map_data_t* mapData;
  typedef struct {
    std::vector<int> coords;
    std::vector<int> strength;
  } river_t;
  std::vector<river_t> rivers;
  TCODRandom* wgRng;

  void addHill(int nbHill, float baseRadius, float radiusVar, float height);
  void buildBaseMap();
  void erodeMap();
  void smoothMap();
  // compute the ground color from the heightmap
  TCODColor getMapColor(float h);
  // get sun light intensity on a point of the map
  float getMapIntensity(float worldX, float worldY, const float lightDir[3]);
  TCODColor getInterpolatedColor(TCODImage* img, float x, float y);
  float getInterpolatedFloat(const float* arr, float x, float y, int width, int height);
  void generateRivers();
  void smoothPrecipitations();
  int getRiverStrength(int riverId);
  void setLandMass(float percent, float waterLevel);
  void computeTemperaturesAndBiomes();
  TCODColor getBiomeColor(EBiome biome, int x, int y);
  void computePrecipitations();
  void computeColors();
  void drawCoasts(TCODImage* img);
  EClimate getClimateFromTemp(float temp);
};
