#include "map.hpp"
#include "dbc.hpp"
#include <vector>
#include <array>
#include <fmt/core.h>
#include "rand.hpp"
#include <utility>

using std::vector, std::pair;
using namespace fmt;

const int WALL_LIGHT_LEVEL = 3;

void dump_map(const std::string &msg, Matrix &map) {
  println("----------------- {}", msg);
  for(auto row : map) {
    for(auto col : row) {
      print("{} ", col);
    }
    print("\n");
  }
}

inline void add_neighbors(PointList &neighbors, Matrix &closed, size_t y, size_t x) {
  size_t h = closed.size();
  size_t w = closed[0].size();
  vector<size_t> rows{y - 1, y, y + 1};
  vector<size_t> cols{x - 1, x, x + 1};

  for(size_t row : rows) {
    for(size_t col : cols) {
      if((0 <= row && row < h) &&
          (0 <= col && col < w) &&
          closed[row][col] == 0)
      {
        closed[row][col] = 1;
        neighbors.push_back({.x=col, .y=row});
      }
    }
  }
}

/**
 * This will create an _inverted_ map that you
 * can run make_rooms and generate on. It will
 * NOT be valid until you actually run generate.
 */
Map::Map(size_t width, size_t height) :
  $limit(1000),
  $width(width),
  $height(height),
  $input_map(height, MatrixRow(width, 1)),
  $walls(height, MatrixRow(width, INV_WALL)),
  $paths(height, MatrixRow(width, 1)),
  $lightmap(height, MatrixRow(width, 0))
{
}

// make explicit
Map::Map(Matrix input_map, Matrix walls_map, int limit) :
  $limit(limit),
  $input_map(input_map),
  $walls(walls_map)
{
  $width = $walls[0].size();
  $height = $walls.size();
}

void Map::make_paths() {
  size_t h = $input_map.size();
  size_t w = $input_map[0].size();

  // Initialize the new array with every pixel at limit distance
  // NOTE: this is normally ones() * limit
  int limit = $limit == 0 ? h * w : $limit;
  Matrix new_arr = Matrix(h, MatrixRow(w, limit));
  Matrix closed = $walls;
  PointList starting_pixels;
  PointList open_pixels;

  // First pass: Add starting pixels and put them in closed
 for(size_t counter = 0; counter < h * w; counter++) {
    size_t x = counter % w;
    size_t y = counter / w;
    if($input_map[y][x] == 0) {
      new_arr[y][x] = 0;
      closed[y][x] = 1;
      starting_pixels.push_back({.x=x,.y=y});
    }
  }

  // Second pass: Add border to open
  for(auto sp : starting_pixels) {
    add_neighbors(open_pixels, closed, sp.y, sp.x);
  }

  // Third pass: Iterate filling in the open list
  int counter = 1; // leave this here so it's available below
  for(; counter < limit && !open_pixels.empty(); ++counter) {
    PointList next_open;
    for(auto sp : open_pixels) {
      new_arr[sp.y][sp.x] = counter;
      add_neighbors(next_open, closed, sp.y, sp.x);
    }
    open_pixels = next_open;
  }

  // Last pass: flood last pixels
  for(auto sp : open_pixels) {
    new_arr[sp.y][sp.x] = counter;
  }

  $paths = new_arr;
}

void Map::make_room(size_t origin_x, size_t origin_y, size_t w, size_t h) {
  dbc::pre("x out of bounds", origin_x < $width);
  dbc::pre("y out of bounds", origin_y < $height);
  dbc::pre("w out of bounds", w <= $width);
  dbc::pre("h out of bounds", h <= $height);

  for(size_t y = origin_y; y < origin_y + h; ++y) {
    dbc::check(y < $walls.size(), "y is out of bounds");
    for(size_t x = origin_x; x < origin_x + w; ++x) {
      dbc::check(x < $walls[y].size(), "x is out of bounds");
      $walls[y][x] = INV_SPACE;
    }
  }
}

inline int make_split(Room &cur, bool horiz) {
  size_t dimension = horiz ? cur.height : cur.width;
  int min = dimension / 4;
  int max = dimension - min;

  return Random::uniform<int>(min, max);
}

void Map::partition_map(Room &cur, int depth) {
  if(cur.width >= 5 && cur.width <= 10 &&
      cur.height >= 5 && cur.height <= 10) {
    $rooms.push_back(cur);
    return;
  }

  bool horiz = cur.width > cur.height ? false : true;
  int split = make_split(cur, horiz);
  Room left = cur;
  Room right = cur;

  if(horiz) {
    dbc::check(split > 0, "split is not > 0");
    dbc::check(split < int(cur.height), "split is too big!");
    left.height = size_t(split - 1);
    right.y = cur.y + split;
    right.height = size_t(cur.height - split);
  } else {
    dbc::check(split > 0, "split is not > 0");
    dbc::check(split < int(cur.width), "split is too big!");

    left.width = size_t(split-1);
    right.x = cur.x + split,
    right.width = size_t(cur.width - split);
  }

  if(depth > 0  && left.width > 5 && left.height > 5) {
    partition_map(left, depth-1);
  }

  if(depth > 0 && right.width > 5 && right.height > 5) {
    partition_map(right, depth-1);
  }
}

void Map::place_rooms(Room &cur) {
  for(auto &cur : $rooms) {
    cur.x += 2;
    cur.y += 2;
    cur.width -= 4;
    cur.height -= 4;
    add_door(cur);
    set_door(cur, INV_SPACE);
    make_room(cur.x, cur.y, cur.width, cur.height);
  }
}

bool Map::neighbors(Point &out, bool greater) {
  std::array<Point, 4> dirs{{
      {out.x,out.y-1},
      {out.x+1,out.y},
      {out.x,out.y+1},
      {out.x-1,out.y}
  }};

  int zero_i = -1;
  int cur = $paths[out.y][out.x];

  // BUG: sometimes cur is in a wall so finding neighbors fails
  for(size_t i = 0; i < dirs.size(); ++i) {
    Point dir = dirs[i];
    int target = inmap(dir.x, dir.y) ? $paths[dir.y][dir.x] : $limit;

    if(target == $limit) continue; // skip unpathable stuff

    int diff = cur - target;

    if(diff == 1) {
      out = {.x=dir.x, .y=dir.y};
      return true;
    } else if(diff == 0) {
      zero_i = i;
    }
  }

  if(zero_i != -1) {
    out = {.x=dirs[zero_i].x, .y=dirs[zero_i].y};
    return true;
  } else {
    return false;
  }
}

bool Map::inmap(size_t x, size_t y) {
  return x < $width && y < $height;
}

void Map::set_door(Room &room, int value) {
  $walls[room.entry.y][room.entry.x] = value;
  $walls[room.exit.y][room.exit.x] = value;
}

void rand_side(Room &room, Point &door) {
  int rand_x = Random::uniform<int>(0, room.width - 1);
  int rand_y = Random::uniform<int>(0, room.height - 1);

  switch(Random::uniform<int>(0,3)) {
    case 0: // north
      door.x = room.x + rand_x;
      door.y = room.y-1;
      break;
    case 1: // south
      door.x = room.x + rand_x;
      door.y = room.y + room.height;
      break;
    case 2: // east
      door.x = room.x + room.width;
      door.y = room.y + rand_y;
      break;
    case 3: // west
      door.x = room.x - 1;
      door.y = room.y + rand_y;
      break;
    default:
      dbc::sentinel("impossible side");
  }
}

void Map::add_door(Room &room) {
  rand_side(room, room.entry);
  rand_side(room, room.exit);
}

bool Map::walk(Point &src, Point &target) {
  // this sets the target for the path
  dbc::check($input_map[target.y][target.x] == 0, "target point not set to 0");

  $walls[src.y][src.x] = INV_WALL;
  $walls[target.y][target.x] = INV_WALL;

  // for the walk this needs to be walls since it's inverted?
  dbc::check($walls[src.y][src.x] == INV_WALL,
      "src room has a wall at exit door");
  dbc::check($walls[target.y][target.x] == INV_WALL,
      "target room has a wall at entry door");

  make_paths();
  bool found = false;
  Point out{src.x, src.y};
  int count = 0;

  do {
    $walls[out.y][out.x] = INV_SPACE;
    found = neighbors(out, true);

    if($paths[out.y][out.x] == 0) {
      $walls[out.y][out.x] = INV_SPACE;
      return true;
    }
  } while(found && out.x > 0 && out.y > 0 && ++count < 100);

  return false;
}

void Map::set_target(const Point &at, int value) {
  $input_map[at.y][at.x] = 0;
}

void Map::clear_light_target(const Point &at) {
  $input_map[at.y][at.x] = 1;
}

void Map::clear_target(const Point &at) {
  $input_map[at.y][at.x] = 1;
}

Point Map::place_entity(size_t room_index) {
  dbc::check(room_index < $rooms.size(), "room_index is out of bounds, not enough rooms");

  Room &start = $rooms[room_index];
  return {start.x+1, start.y+1};
}

void Map::generate() {
  Room root{
    .x = 0,
    .y = 0,
    .width = $width,
    .height = $height
  };

  partition_map(root, 10);
  place_rooms(root);

  for(size_t i = 0; i < $rooms.size() - 1; i++) {
    Room &src = $rooms[i];
    Room &target = $rooms[i+1];
    set_target(target.entry);
    bool found = walk(src.exit, target.entry);
    if(!found) {
      println("ROOM NOT FOUND!");
    }
    clear_target(target.entry);
  }

  Room &src = $rooms.back();
  Room &target = $rooms.front();

  set_target(target.entry);
  walk(src.exit, target.entry);
  clear_target(target.entry);

  for(size_t y = 0; y < $height; ++y) {
    for(size_t x = 0; x < $width; ++x) {
      $walls[y][x] = !$walls[y][x];
    }
  }
}

bool Map::iswall(size_t x, size_t y) {
  return $walls[y][x] == WALL_VALUE;
}

void Map::dump() {
  dump_map("PATHS", $paths);
  dump_map("WALLS", $walls);
  dump_map("INPUT", $input_map);
}

bool Map::can_move(Point move_to) {
  return inmap(move_to.x, move_to.y) &&
    !iswall(move_to.x, move_to.y);
}

Point Map::map_to_camera(const Point &loc, const Point &cam_orig) {
  return {loc.x - cam_orig.x, loc.y - cam_orig.y};
}

Point Map::center_camera(const Point &around, size_t view_x, size_t view_y) {
  int high_x = int(width() - view_x);
  int high_y = int(height() - view_y);
  int center_x = int(around.x - view_x / 2);
  int center_y = int(around.y - view_y / 2);

  // BUG: is clamp really the best thing here? this seems wrong.
  size_t start_x = high_x > 0 ? std::clamp(center_x, 0, high_x) : 0;
  size_t start_y = high_y > 0 ? std::clamp(center_y, 0, high_y) : 0;

  return {start_x, start_y};
}

void Map::reset_light() {
  for(auto &row : $lightmap) {
    for(size_t i = 0; i < row.size(); i++) {
      row[i] = lighting::MIN;
    }
  }
}

void Map::set_light_target(const Point &at, int value) {
  set_target(at, value);
}


void Map::path_light() {
    make_paths();
}

void Map::light_box(LightSource source, Point from, Point &min_out, Point &max_out) {
  using std::min, std::max;
  min_out.x = max(int(from.x), source.distance) - source.distance;
  max_out.x = min(from.x + source.distance, width() - 1);
  min_out.y = max(int(from.y), source.distance) - source.distance;
  max_out.y = min(from.y + source.distance, width() - 1);
}

int Map::light_level(int level, size_t x, size_t y) {
  size_t at = level + $paths[y][x];
  int cur_level = $lightmap[y][x];
  int new_level = at < lighting::LEVELS.size() ? lighting::LEVELS[at] : lighting::MIN;
  return cur_level < new_level ? new_level : cur_level;
}

void Map::render_light(LightSource source, Point at) {
  const int UNPATH = $limit;
  Point min, max;
  light_box(source, at, min, max);
  clear_light_target(at);
  vector<Point> has_light;

  for(size_t x = min.x; x <= max.x; ++x) {
    for(size_t y = min.y; y <= max.y; ++y) {
      if($paths[y][x] != UNPATH) {
        $lightmap[y][x] = light_level(source.strength, x, y);
        has_light.push_back({x,y});
      }
    }
  }

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

        if($paths[point.y+j][point.x+i] == UNPATH) {
          $lightmap[point.y+j][point.x+i] = light_level(wall_light, point.x, point.y);
        }
      }
    }
  }
}