#include "systems.hpp"
#include <fmt/core.h>
#include <string>
#include <cmath>
#include "rand.hpp"
#include "collider.hpp"
#include "events.hpp"
#include "ftxui/screen/color.hpp"
#include "ftxui/screen/terminal.hpp"  // for SetColorSupport, Color, TrueColor
#include "dbc.hpp"

const bool DEBUG_MAP=false;

using std::string;
using namespace fmt;
using namespace components;
using ftxui::Color;

const int LIGHT_MIN = 20;
const int LIGHT_MAX = 160;

void System::lighting(DinkyECS::World &world, Map &game_map, Player &player) {
  const auto& player_light = world.get<LightSource>(player.entity);
  auto &paths = game_map.paths();
  auto &lighting = game_map.lighting();
  std::vector<Point> has_light;

  for(size_t x = 0; x < game_map.width(); ++x) {
    for(size_t y = 0; y < game_map.height(); ++y) {
      int dnum = paths[y][x];
      int light = std::clamp(255 - (dnum * player_light.strength), LIGHT_MIN, LIGHT_MAX);
      lighting[y][x] = light;

      if(light > LIGHT_MIN) {
        has_light.push_back({x,y});
      }
    }
  }


  const int UNPATH = game_map.limit();

  for(auto point : has_light) {
    for(int i = -1; i <= 1; i++) {
      for(int j = -1; j <= 1; j++) {
        if(!game_map.inmap(point.x+i, point.y+j)) continue;

        if(paths[point.y+j][point.x+i] == UNPATH) {
          lighting[point.y+j][point.x+i] = LIGHT_MAX;
        }
      }
    }
  }
}

void System::enemy_pathing(DinkyECS::World &world, Map &game_map, Player &player) {
  // TODO: this will be on each enemy not a global thing
  const auto &config = world.get_the<EnemyConfig>();
  const auto &player_position = world.get<Position>(player.entity);
  game_map.set_target(player_position.location);
  game_map.make_paths();

  world.query<Position, Motion>([&](const auto &ent, auto &position, auto &motion) {
    if(ent != player.entity) {
      Point out = position.location; // copy
      if(game_map.distance(out) < config.HEARING_DISTANCE) {
        game_map.neighbors(out, false);
        motion = { int(out.x - position.location.x), int(out.y - position.location.y)};
      }
    }
  });
  game_map.clear_target(player_position.location);
}

void System::init_positions(DinkyECS::World &world) {
  auto &collider = world.get_the<spatial_map>();

  world.query<Position, Combat>([&](const auto &ent, auto &pos, auto &combat) {
      if(!combat.dead) {
        collider.insert(pos.location, ent);
      }
  });

  world.query<Position, Loot>([&](const auto &ent, auto &pos, auto &loot) {
      collider.insert(pos.location, ent);
  });
}

inline void move_entity(spatial_map &collider, Map &game_map, Position &position, Motion &motion, DinkyECS::Entity ent) {
  Point move_to = {
    position.location.x + motion.dx,
    position.location.y + motion.dy
  };
  motion = {0,0}; // clear it after getting it

  // it's a wall, skip
  if(!game_map.can_move(move_to)) return;
  // there's collision skip
  if(collider.occupied(move_to)) return;

  // all good, do the move
  collider.move(position.location, move_to, ent);
  position.location = move_to;
}

void System::motion(DinkyECS::World &world, Map &game_map) {
  auto &collider = world.get_the<spatial_map>();

  world.query<Position, Motion>([&](const auto &ent, auto &position, auto &motion) {
    // don't process entities that don't move
    if(motion.dx != 0 || motion.dy != 0) {
      move_entity(collider, game_map, position, motion, ent);
    }
  });
}

void System::death(DinkyECS::World &world) {
  auto &collider = world.get_the<spatial_map>();

  world.query<Position, Combat>([&](const auto &ent, auto &position, auto &combat) {
    // bring out yer dead
    if(combat.hp <= 0 && !combat.dead) {
      combat.dead = true;
      // take them out of collision map
      collider.remove(position.location);

      // remove their motion so they're dead
      world.remove<Motion>(ent);
    }
  });
}

void System::collision(DinkyECS::World &world, Player &player) {
  auto& collider = world.get_the<spatial_map>();
  const auto& player_position = world.get<Position>(player.entity);
  auto& player_combat = world.get<Combat>(player.entity);

  // this is guaranteed to not return the given position
  auto [found, nearby] = collider.neighbors(player_position.location);

  if(found) {

    for(auto entity : nearby) {
      if(world.has<Combat>(entity)) {
        auto& enemy_combat = world.get<Combat>(entity);

        Events::Combat result {
          player_combat.attack(enemy_combat),
          enemy_combat.attack(player_combat)
        };

        world.send<Events::GUI>(Events::GUI::COMBAT, entity, result);
      } else if(world.has<Loot>(entity)) {
        auto loot = world.get<Loot>(entity);
        auto &loot_pos = world.get<Position>(entity);
        auto &inventory = world.get<Inventory>(player.entity);
        auto &light = world.get<LightSource>(player.entity);

        world.send<Events::GUI>(Events::GUI::LOOT, entity, loot);
        inventory.gold += loot.amount;
        light.strength = 100;
        collider.remove(loot_pos.location);
      } else {
        println("UNKNOWN COLLISION TYPE {}", entity);
      }
    }
  }
}

void System::draw_entities(DinkyECS::World &world, Map &game_map, ftxui::Canvas &canvas, const Point &cam_orig, size_t view_x, size_t view_y) {
  auto &lighting = game_map.lighting();

  world.query<Position, Tile>([&](const auto &ent, auto &pos, auto &tile) {
    if(pos.location.x >= cam_orig.x && pos.location.x <= cam_orig.x + view_x
        && pos.location.y >= cam_orig.y && pos.location.y <= cam_orig.y + view_y) {
      Point loc = game_map.map_to_camera(pos.location, cam_orig);
      int light_value = lighting[pos.location.y][pos.location.x];

      // the 2 and 4 are from ftxui::Canvas since it does a kind of "subpixel" drawing
      canvas.DrawText(loc.x*2, loc.y*4, tile.chr, [light_value](auto &pixel) {
          pixel.foreground_color = Color::HSV(255, 200, light_value + 20);
          pixel.background_color = Color::HSV(30, 20, light_value / 5);
      });
    }
  });
}

void System::draw_map(DinkyECS::World &world, Map &game_map, ftxui::Canvas &canvas, size_t view_x, size_t view_y) {
  const auto& config = world.get_the<MapConfig>();
  const auto& player = world.get_the<Player>();
  const auto& player_position = world.get<Position>(player.entity);
  Point start = game_map.center_camera(player_position.location, view_x, view_y);
  auto &walls = game_map.walls();
  auto &paths = game_map.paths();
  auto &lighting = game_map.lighting();

  size_t end_x = std::min(view_x, game_map.width() - start.x);
  size_t end_y = std::min(view_y, game_map.height() - start.y);

  for(size_t x = 0; x < end_x; ++x) {
    for(size_t y = 0; y < end_y; ++y) {
      string tile = walls[start.y+y][start.x+x] == 1 ? config.WALL_TILE : config.FLOOR_TILE;
      // "WALL_TILE": "\u2591",
      // "WALL_TILE": "\ua5b8",
      int light_value = lighting[start.y+y][start.x+x];

      if(tile == config.WALL_TILE) {
        canvas.DrawText(x * 2, y * 4, config.WALL_TILE, [light_value](auto &pixel) {
            if(light_value > LIGHT_MIN) {
              pixel.foreground_color = Color::HSV(230, 20, 10);
              pixel.background_color = Color::HSV(230, 20, light_value / 2);
            } else {
              pixel.foreground_color = Color::HSV(230, 20, 20);
              pixel.background_color = Color::HSV(230, 20, 30);
            }
        });
      } else if(DEBUG_MAP) {
        int dnum = paths[start.y+y][start.x+x];
        string num = format("{:x}", dnum);
        num = num.size() > 2 ? "*" : num;

        canvas.DrawText(x * 2, y * 4, num, [dnum, light_value](auto &pixel) {
           pixel.foreground_color = Color::HSV(dnum * 20, 150, 200);
           pixel.background_color = Color::HSV(30, 20, light_value / 5);
        });
      } else {
        canvas.DrawText(x * 2, y * 4, tile, [light_value](auto &pixel) {
            pixel.foreground_color = Color::HSV(30, 40, light_value);
            pixel.background_color = Color::HSV(30, 20, light_value / 5);
        });
      }
    }
  }

  System::draw_entities(world, game_map, canvas, start, view_x, view_y);
}