#include "Generate.h"

#include <climits>
#include <iostream>

std::vector<Point> Generate::_DIRECTIONS1 = {Point(0, 1), Point(0, -1),
                                             Point(1, 0), Point(-1, 0)};
std::vector<Point> Generate::_8DIRECTIONS1 = {
    Point(0, 1), Point(0, -1), Point(1, 0),   Point(-1, 0),
    Point(1, 1), Point(1, -1), Point(-1, -1), Point(-1, 1)};
std::vector<Point> Generate::_DIRECTIONS2 = {Point(0, 2), Point(0, -2),
                                             Point(2, 0), Point(-2, 0)};
std::vector<Point> Generate::_8DIRECTIONS2 = {
    Point(0, 2), Point(0, -2), Point(2, 0),   Point(-2, 0),
    Point(2, 2), Point(2, -2), Point(-2, -2), Point(-2, 2)};
std::vector<Point> Generate::_DISCONNECT = {
    Point(0, 2),   Point(0, -2), Point(2, 0),
    Point(-2, 0),  Point(2, 2),  Point(2, -2),
    Point(-2, -2), Point(-2, 2), Point(0, 2),
    Point(0, -2),  Point(2, 0),  Point(-2, 0),
    Point(2, 2),   Point(2, -2), Point(-2, -2),
    Point(-2, 2),  Point(0, 4),  Point(0, -4),
    Point(4, 0),   Point(-4, 0),  // Used to make the discontiguous shapes
};
std::vector<Point> Generate::_SHAPEDIRECTIONS =
    {};  // This will eventually be set to one of the above lists

// Make a maze puzzle. The maze will have one solution. id - id of the puzzle
/*void Generate::generateMaze(int id) {
  while (!generate_maze(id, 0, 0))
    ;
}

// Make a maze puzzle. The maze will have one solution. id - id of the puzzle.
// numStarts - how many starts to add (only one will be valid). numExits - how
// many exits to add. All will work Setting numStarts or numExits to 0 will keep
// the starts/exits where they originally were, otherwise the starts/exits
// originally there will be removed and new ones randomly placed.
void Generate::generateMaze(int id, int numStarts, int numExits) {
  while (!generate_maze(id, numStarts, numExits))
    ;
}*/

// Read in default panel data, such as dimensions, symmetry, starts/exits, etc.
// id - id of the puzzle
void Generate::initPanel() {
  _panel = std::make_unique<Panel>();
  _panel->Resize(_width, _height);

  // erase_path();

  //_panelData.resize(_height);
  // for (auto& row : _panelData) row.resize(_width);

  if (hasFlag(Config::TreehouseLayout)) {
    init_treehouse_layout();
  }
  if (hasFlag(Config::RegularStartEnd)) {
    if (_symmetry == Panel::Rotational) {
      setSymbol(Decoration::Start, 0, 0);
      setSymbol(Decoration::Exit, 0, _panel->height() - 1);

      setSymbol(Decoration::Start, _panel->width() - 1, _panel->height() - 1);
      setSymbol(Decoration::Exit, _panel->width() - 1, 0);
    } else if (_symmetry == Panel::Vertical) {
      setSymbol(Decoration::Exit, 0, 0);
      setSymbol(Decoration::Start, 0, _panel->height() - 1);

      setSymbol(Decoration::Start, _panel->width() - 1, _panel->height() - 1);
      setSymbol(Decoration::Exit, _panel->width() - 1, 0);
    } else if (_symmetry == Panel::Horizontal) {
      setSymbol(Decoration::Start, 0, 0);
      setSymbol(Decoration::Start, 0, _panel->height() - 1);

      setSymbol(Decoration::Exit, _panel->width() - 1, _panel->height() - 1);
      setSymbol(Decoration::Exit, _panel->width() - 1, 0);
    } else {
      setSymbol(Decoration::Start, 0, _panel->height() - 1);
      setSymbol(Decoration::Exit, _panel->width() - 1, 0);
    }
  }

  if (_custom_grid.size() >
      0) {  // If we want to start with a certain default grid when generating
    if (_custom_grid.size() < _panel->width()) {
      _custom_grid.resize(_panel->width());
    }
    if (_custom_grid[_custom_grid.size() - 1].size() < _panel->height()) {
      for (auto& row : _custom_grid) {
        row.resize(_panel->height());
      }
    }
    for (int x = 0; x < _panel->width(); x++) {
      for (int y = 0; y < _panel->height(); y++) {
        set(x, y, _custom_grid[x][y]);
      }
    }
  }
  // Sync up start/exit points between panel and generator. If both are
  // different, the generator's start/exit point list will be used
  for (Point e : _starts) {
    _panel->SetGridSymbol(e.first, e.second, Decoration::Start,
                          Decoration::Color::None);
  }
  for (Point e : _exits) {
    _panel->SetGridSymbol(e.first, e.second, Decoration::Exit,
                          Decoration::Color::None);
  }

  // Fill gridpos with every available grid block
  _gridpos.clear();
  for (int x = 1; x < _panel->width(); x += 2) {
    for (int y = 1; y < _panel->height(); y += 2) {
      /*if (!(hasFlag(Config::PreserveStructure) &&
            (get(x, y) & Decoration::Empty) == Decoration::Empty))*/
      _gridpos.emplace(Point(x, y));
    }
  }
  // Init the open positions available for symbols. Defaults to every grid block
  // unless a custom openpos has been specified
  if (openPos.size() > 0)
    _openpos = openPos;
  else
    _openpos = _gridpos;
  for (Point p : blockPos)
    _openpos.erase(p);  // Remove the points which the user has defined to not
                        // place symbols on
  for (Point p : _splitPoints)
    _openpos.erase(p);  // The split points will have erasers and cannot have
                        // any other symbols placed on them
  _fullGaps = hasFlag(Config::FullGaps);
  _panel->symmetry =
      _symmetry;  // Init user-defined puzzle symmetry if not "None".
  // 0x00076 (Symmetry Island Fading Lines 7) and 0x01D3F (Keep Blue Pressure
  // Plates) are exceptions because they need to have symmetry removed
  if (pathWidth != 1)
    _panel->pathWidth = pathWidth;  // Init path scale. "1" is considered the
                                    // default, and therefore means no change.

  if (hasFlag(Config::WriteInvisible)) {
    _panel->SetInvisibleSymmetry(true);
  }
}

// Place a specific symbol into the puzzle at the specified location. The
// generator will add other symbols, but will leave the set ones where they are.
// symbol - the symbol to place. //x, y - the coordinates to put it at. (0, 0)
// is at top left. Lines are at even coordinates and grid blocks at odd
// coordinates
void Generate::setSymbol(Decoration::Shape symbol, int x, int y) {
  if (_custom_grid.size() < x + 1) {
    _custom_grid.resize(x + 1, std::vector<int>());
    for (auto& row : _custom_grid) {
      row.resize(_custom_grid[0].size(), 0);
    }
  }
  for (auto& row : _custom_grid) {
    if (row.size() < y + 1) {
      row.resize(y + 1, 0);
    }
  }

  if (symbol == Decoration::Start)
    _starts.emplace(Point(x, y));
  else if (symbol == Decoration::Exit)
    _exits.emplace(Point(x, y));
  else
    _custom_grid[x][y] = symbol;  // Starts and exits are not set into the grid
}

// Set the dimensions of the puzzles. This setting will persist between puzzle
// generation calls. (0, 0) will have the generator use the same dimensions as
// the orignal puzzle. width, height - the dimensions to use, measured in grid
// blocks.
void Generate::setGridSize(int width, int height) {
  if (width <= 0 || height <= 0) {
    _width = 0;
    _height = 0;
  } else {
    _width = width * 2 + 1;
    _height = height * 2 + 1;
  }
}

// Set the type of symmetry to use. This setting will persist between puzzle
// generation calls. Using "None" will make the generator use the existing
// puzzle symmetry.
void Generate::setSymmetry(Panel::Symmetry symmetry) {
  _symmetry = symmetry;
  if (_symmetry == Panel::Symmetry::ParallelV ||
      _symmetry == Panel::Symmetry::ParallelVFlip) {
    std::vector<Point> points;
    for (int y = 0; y < _height; y += 2)
      points.emplace_back(Point(_width / 2, y));
    setObstructions(points);  // This prevents the generator from invalidly
                              // passing through the center line
  }
  if (_symmetry == Panel::Symmetry::ParallelH ||
      _symmetry == Panel::Symmetry::ParallelHFlip) {
    std::vector<Point> points;
    for (int x = 0; x < _width; x += 2)
      points.emplace_back(Point(x, _height / 2));
    setObstructions(points);  // This prevents the generator from invalidly
                              // passing through the center line
  }
}

// Write out panel data to the puzzle with the given id
void Generate::write(int id) {
  std::vector<std::vector<int>> backupGrid;
  /*  if (hasFlag(Config::DisableReset))
      backupGrid =
          _panel->_grid;  // Allows panel data to be preserved after writing.
                          // Normally writing erases the panel data.*/

  erase_path();

  // TODO: write

  // Undo any one-time config changes
  if (_oneTimeAdd) {
    _config &= ~_oneTimeAdd;
    _oneTimeAdd = 0;
  }
  if (_oneTimeRemove) {
    _config |= _oneTimeRemove;
    _oneTimeRemove = 0;
  }
  // Manually advance seed by 1 each generation to prevent seeds "funneling"
  // from repeated fails
  Random::seed(_seed);
  _seed = Random::rand();
}

// Reset all config flags and persistent settings, including width/height and
// symmetry.
void Generate::resetConfig() {
  setGridSize(0, 0);
  _symmetry = Panel::Symmetry::None;
  pathWidth = 1;
  if (hasFlag(Config::DisableReset)) {
    resetVars();
  }
  _config = 0;
  _oneTimeAdd = Config::None;
  _oneTimeRemove = Config::None;
  arrowColor = backgroundColor = successColor = {0, 0, 0, 0};
}

//----------------------Private--------------------------

// Add the point (pos) to the intended solution path, using symmetry if
// applicable.
void Generate::set_path(Point pos) {
  set(pos, PATH);
  _path.insert(pos);
  if (_panel->symmetry) {
    _path1.insert(pos);
    Point sp = get_sym_point(pos);
    set(sp, PATH);
    _path.insert(sp);
    _path2.insert(sp);
  }
}

// Remove the path and all symbols from the grid. This does not affect
// starts/exits. If PreserveStructure is active, open gaps will be kept. If a
// custom grid is set, this will reset it back to the custom grid state.
void Generate::clear() {
  if (_custom_grid.size() > 0) {
    for (int x = 0; x < _panel->width(); x++) {
      for (int y = 0; y < _panel->height(); y++) {
        set(x, y, _custom_grid[x][y]);
      }
    }
  } else
    for (int x = 0; x < _panel->width(); x++) {
      for (int y = 0; y < _panel->height(); y++) {
        /*if (hasFlag(Config::PreserveStructure) &&
            (_panel->_grid[x][y] == OPEN ||
             (_panel->_grid[x][y] & 0x60000f) == NO_POINT ||
             (_panel->_grid[x][y] & Decoration::Empty) == Decoration::Empty))
          continue;*/
        set(x, y, 0);
      }
    }
  //_panel->_style &= ~0x2ff8;  // Remove all element flags
  _path.clear();
  _path1.clear();
  _path2.clear();
}

// Reset generator variables and lists used when generating puzzles. (not config
// settings)
void Generate::resetVars() {
  _panel = NULL;  // This is needed for the generator to read in the next panel
  _starts.clear();
  _exits.clear();
  _custom_grid.clear();
  hitPoints.clear();
  _obstructions.clear();
  openPos.clear();
  blockPos.clear();
  _splitPoints.clear();
}

// Place start and exits in central positions like in the treehouse
void Generate::init_treehouse_layout() {
  // bool pivot = _panel->_endpoints.size() > 2;
  bool pivot = false;
  setSymbol(Decoration::Start, _panel->width() / 2, _panel->height() - 1);
  setSymbol(Decoration::Exit, _panel->width() / 2, 0);
  if (pivot) {
    setSymbol(Decoration::Exit, _panel->width() - 1, _panel->height() / 2);
    setSymbol(Decoration::Exit, 0, _panel->height() / 2);
  }
}
/*
// Private version of generateMaze. Should be called again if false is returned.
// The algorithm works by generating a correct path, then extending lines off of
// it until the maze is filled.
bool Generate::generate_maze(int id, int numStarts, int numExits) {
  initPanel(id);

  if (numStarts > 0) place_start(numStarts);
  if (numExits > 0) place_exit(numExits);

  // Prevent start and exit from overlapping, except in one one particular
  // puzzle (0x00083).
  if (id == 0x00083 && _width == 15 && _height == 15) {
    clear();
    _panel->_endpoints.clear();
    _exits.clear();
    Point start = pick_random(_starts);
    _panel->SetGridSymbol(start.first, start.second, Decoration::Exit,
                          Decoration::Color::None);
    Point sp = get_sym_point(start);
    _panel->SetGridSymbol(sp.first, sp.second, Decoration::Exit,
                          Decoration::Color::None);
    set_path(start);
    set_path(sp);
  } else {
    for (Point p : _starts)
      if (_exits.count(p)) return false;

    clear();
    if (hasFlag(Generate::Config::ShortPath)) {
      while (!generate_path_length(
          (_panel->width() + _panel->height()),
          min((_panel->width() + _panel->height()) * 2,
              (_panel->width() / 2 + 1) * (_panel->height() / 2 + 1) * 1 / 2)))
        clear();
    }
    while (!generate_path_length(
        (_panel->width() + _panel->height()),
        min((_panel->width() + _panel->height()) * 2,
            (_panel->width() / 2 + 1) * (_panel->height() / 2 + 1) * 4 / 5)))
      clear();
  }

  std::set<Point> path = _path;  // Backup

  // Extra false starts are tracked in a separate list so that the generator can
  // make sure to extend each of them by a higher amount than usual.
  std::set<Point> extraStarts;
  for (Point pos : _starts) {
    if (!_path.count(pos)) {
      extraStarts.insert(pos);
    }
    set_path(pos);
  }
  // Check to see if the correct path runs over any of the false start points.
  // If so, start over
  if (extraStarts.size() !=
      (_panel->symmetry ? _starts.size() / 2 - 1 : _starts.size() - 1))
    return false;

  std::set<Point> check;
  std::vector<Point> deadEndH, deadEndV;
  for (Point p : _path) {
    if (p.first % 2 == 0 && p.second % 2 == 0)
      check.insert(p);  // Only extend off of the points at grid intersections.
  }
  while (check.size() > 0) {
    // Pick a random extendable point and extend it for some randomly chosen
    // amount of units.
    Point randomPos = (extraStarts.size() > 0 ? pick_random(extraStarts)
                                              : pick_random(check));
    Point pos = randomPos;
    for (int i = (extraStarts.size() > 0 ? 7 : 1); i >= 0;
         i--) {  // False starts are extended by up to 7 units. Other points are
                 // extended 1 unit at a time
      std::vector<Point> validDir;
      for (Point dir : _DIRECTIONS2) {
        if (!off_edge(pos + dir) && get(pos + dir) == 0) {
          validDir.push_back(dir);
        }
      }
      if (validDir.size() < 2)
        check.erase(pos);  // If there are 0 or 1 open directions, the point
                           // cannot be extended again.
      if (validDir.size() == 0) {
        if (extraStarts.size() > 0) {
          return false;  // Not all the starts were extended successfully.
        }
        // If full gaps mode is enabled, detect dead ends, so that square tips
        // can be put on them
        if (_fullGaps && !_exits.count(pos) && !_starts.count(pos)) {
          int countOpenRow = 0, countOpenColumn = 0;
          for (Point dir2 : _DIRECTIONS1) {
            Point added = pos + dir2;
            if (!off_edge(added) && _drawnPath[added.second][added.first]) {
              if (dir2.first == 0)
                countOpenColumn++;
              else
                countOpenRow++;
            }
          }
          if (countOpenRow + countOpenColumn == 1) {
            if (countOpenRow)
              deadEndH.push_back(pos);
            else
              deadEndV.push_back(pos);
          }
        }
        break;  // A dead end has been reached, extend a different point
      }
      Point dir = pick_random(validDir);
      Point newPos = pos + dir;
      set_path(newPos);
      set_path(pos + dir / 2);
      check.insert(newPos);
      pos = newPos;
    }
    if (extraStarts.size() > 0) extraStarts.erase(randomPos);
  }
  // Put openings or gaps in any unused row or column segment
  for (int y = 0; y < _panel->height(); y++) {
    for (int x = (y + 1) % 2; x < _panel->width(); x += 2) {
      if (!_drawnPath[y][x]) {
        _panel->SetGridSymbol(x, y,
                              _fullGaps    ? OPEN
                              : x % 2 == 0 ? Decoration::Gap_Column
                                           : Decoration::Gap_Row);
        if (_panel->symmetry) {
          Point sp = get_sym_point(Point(x, y));
          if (sp.first == x && sp.second == y ||
              sp.first == x && x % 2 == 0 && abs(sp.second - y) <= 2 ||
              sp.second == y && y % 2 == 0 && abs(sp.first - x) <= 2 ||
              abs(sp.first - x) == 1) {
            _drawnPath[y][x] = true;
          } else if (Random::rand() % 2 == 0) {
            _drawnPath[sp.second][sp.first] = true;
          } else {
            _drawnPath[y][x] = true;
            _panel->SetGridSymbol(sp, _fullGaps    ? OPEN
                                      : x % 2 == 0 ? Decoration::Gap_Column
                                                   : Decoration::Gap_Row);
          }
        }
      }
    }
  }
  // Put square ends on any dead ends
  for (Point p : deadEndH) {
    _panel->SetGridSymbol(p, Decoration::Gap_Row);
  }
  for (Point p : deadEndV) {
    _panel->SetGridSymbol(p, Decoration::Gap_Column);
  }
  _path = path;  // Restore backup of the correct solution for testing purposes
  std::vector<std::string> solution;  // For debugging only
  for (int y = 0; y < _panel->height(); y++) {
    std::string row;
    for (int x = 0; x < _panel->width(); x++) {
      if (_path.count(Point(x, y))) {
        row += "xx";
      } else
        row += "    ";
    }
    solution.push_back(row);
  }
  if (!hasFlag(Config::DisableWrite)) write(id);
  return true;
}*/

void Generate::generate(int width, int height, PuzzleSymbols symbols) {
  while (!generateInternal(width, height, symbols))
    ;
}

// The primary generation function. id - id of the puzzle. symbols - a structure
// representing the amount and types of each symbol to add to the puzzle The
// algorithm works by making a random path and then adding the chosen symbols to
// the grid in such a way that they will be satisfied by the path. if at some
// point the generator fails to add a symbol while still making the solution
// correct, the function returns false and must be called again.
bool Generate::generateInternal(int width, int height, PuzzleSymbols symbols) {
  _width = width * 2 + 1;
  _height = height * 2 + 1;

  initPanel();

  // Multiple erasers are forced to be separate by default. This is because
  // combining them causes unpredictable and inconsistent behavior.
  if (symbols.getNum(Decoration::Eraser) > 1 &&
      !hasFlag(Config::CombineErasers)) {
    setSymbol(Decoration::Gap_Row, 1, 0);
    setSymbol(Decoration::Gap_Row, _panel->width() - 2, _panel->height() - 1);
    _splitPoints = {Point(1, 1),
                    Point(_panel->width() - 2, _panel->height() - 2)};
    // initPanel(id);  // Re-initing to account for the newly added information
  }

  // Init parity for full dot puzzles
  if (symbols.getNum(Decoration::Dot) >= _panel->get_num_grid_points() - 2)
    _parity =
        (_panel->get_parity() +
         (!symbols.any(Decoration::Start)  ? get_parity(pick_random(_starts))
          : !symbols.any(Decoration::Exit) ? get_parity(pick_random(_exits))
                                           : Random::rand() % 2)) %
        2;
  else
    _parity = -1;  //-1 indicates a non-full dot puzzle

  if (symbols.any(Decoration::Start))
    place_start(symbols.getNum(Decoration::Start));
  if (symbols.any(Decoration::Exit))
    place_exit(symbols.getNum(Decoration::Exit));

  // Make a random path unless a fixed one has been defined
  if (customPath.size() == 0) {
    int fails = 0;
    while (!generate_path(symbols)) {
      if (fails++ > 20)
        return false;  // It gets several chances to make a path so that the
                       // whole init process doesn't have to be repeated so many
                       // times
    }
  } else
    _path = customPath;

  std::vector<std::string> solution;  // For debugging only
  for (int y = 0; y < _panel->height(); y++) {
    std::string row;
    for (int x = 0; x < _panel->width(); x++) {
      if (get(x, y) == PATH) {
        row += "xx";
      } else
        row += "  ";
    }
    solution.push_back(row);
  }

  // Attempt to add the symbols
  if (!place_all_symbols(symbols)) return false;

  for (const auto& row : solution) {
    std::cout << row << std::endl;
  }

  erase_path();
  std::cout << _panel->Write() << std::endl;

  return true;
}

// Place the provided symbols onto the puzzle. symbols - a structure describing
// types and amounts of symbols to add.
bool Generate::place_all_symbols(PuzzleSymbols& symbols) {
  std::vector<int> eraseSymbols;
  std::vector<int> eraserColors;
  // If erasers are present, choose symbols to be erased and remove them
  // pre-emptively
  for (std::pair<int, int> s : symbols[Decoration::Eraser]) {
    for (int i = 0; i < s.second; i++) {
      eraserColors.push_back(s.first & 0xf);
      eraseSymbols.push_back(hasFlag(Config::FalseParity)
                                 ? Decoration::Dot_Intersection
                                 : symbols.popRandomSymbol());
    }
  }

  // Symbols are placed in stages according to their type
  // In each of these loops, s.first is the symbol and s.second is the amount of
  // it to add

  _SHAPEDIRECTIONS =
      (hasFlag(Config::DisconnectShapes) ? _DISCONNECT : _DIRECTIONS2);
  int numShapes = 0, numRotate = 0, numNegative = 0;
  std::vector<int> colors, negativeColors;
  for (std::pair<int, int> s : symbols[Decoration::Poly]) {
    for (int i = 0; i < s.second; i++) {
      if (s.first & Decoration::Can_Rotate) numRotate++;
      if (s.first & Decoration::Negative) {
        numNegative++;
        negativeColors.push_back(s.first & 0xf);
      } else {
        numShapes++;
        colors.push_back(s.first & 0xf);
      }
    }
  }
  if (numShapes > 0 && !place_shapes(colors, negativeColors, numShapes,
                                     numRotate, numNegative) ||
      numShapes == 0 && numNegative > 0)
    return false;

  _stoneTypes = static_cast<int>(symbols[Decoration::Stone].size());
  _bisect = true;  // This flag helps the generator prevent making two adjacent
                   // regions of stones the same color
  for (std::pair<int, int> s : symbols[Decoration::Stone])
    if (!place_stones(s.first & 0xf, s.second)) return false;
  for (std::pair<int, int> s : symbols[Decoration::Triangle])
    if (!place_triangles(s.first & 0xf, s.second, s.first >> 16)) return false;
  for (std::pair<int, int> s : symbols[Decoration::Arrow])
    if (!place_arrows(s.first & 0xf, s.second, s.first >> 12)) return false;
  for (std::pair<int, int> s : symbols[Decoration::Star])
    if (!place_stars(s.first & 0xf, s.second)) return false;
  if (symbols.style == Panel::Style::HAS_STARS &&
      hasFlag(Generate::Config::TreehouseLayout) && !checkStarZigzag())
    return false;
  if (eraserColors.size() > 0 && !place_erasers(eraserColors, eraseSymbols))
    return false;
  for (std::pair<int, int> s : symbols[Decoration::Dot])
    if (!place_dots(s.second, static_cast<Decoration::Color>(s.first & 0xf),
                    (s.first & ~0xf) == Decoration::Dot_Intersection))
      return false;
  for (std::pair<int, int> s : symbols[Decoration::Gap])
    if (!place_gaps(s.second)) return false;
  return true;
}

// Generate a random path for a puzzle with the provided symbols.
// The path starts at a random start and will not cross through walls or
// symbols. Puzzle symbols are provided because they can influence how long the
// path should be.
bool Generate::generate_path(PuzzleSymbols& symbols) {
  clear();

  if (_obstructions.size() > 0) {
    std::vector<Point> walls = pick_random(_obstructions);
    for (Point p : walls)
      if (get(p) == 0)
        set(p, p.first % 2 == 0 ? Decoration::Gap_Column : Decoration::Gap_Row);
    bool result =
        (hasFlag(Config::ShortPath) ? generate_path_length(1)
         : _parity != -1            ? generate_longest_path()
         : hitPoints.size() > 0
             ? generate_special_path()
             : generate_path_length(_panel->get_num_grid_points() * 3 / 4));
    for (Point p : walls)
      if (get(p) & Decoration::Gap) set(p, 0);
    return result;
  }

  if (hitPoints.size() > 0) {
    return generate_special_path();
  }

  if (_parity != -1 || hasFlag(Generate::LongestPath)) {
    return generate_longest_path();
  }

  if (hasFlag(Config::ShortPath)) return generate_path_length(1);

  // The diagonal symmetry puzzles have a lot of points that can't be hit, so I
  // have to reduce the path length
  if (_panel->symmetry == Panel::Symmetry::FlipXY ||
      _panel->symmetry == Panel::Symmetry::FlipNegXY) {
    return generate_path_length(_panel->get_num_grid_points() * 3 / 4 -
                                _panel->width() / 2);
  }

  // Dot puzzles have a longer path by default. Vertical/horizontal symmetry
  // puzzles are also longer because they tend to be too simple otherwise
  if (hasFlag(Config::LongPath) ||
      symbols.style == Panel::Style::HAS_DOTS &&
          !hasFlag(Config::PreserveStructure) &&
          !(_panel->symmetry == Panel::Symmetry::Vertical &&
                (_panel->width() / 2) % 2 == 0 ||
            _panel->symmetry == Panel::Symmetry::Horizontal &&
                (_panel->height() / 2) % 2 == 0)) {
    return generate_path_length(_panel->get_num_grid_points() * 7 / 8);
  }

  // For stone puzzles, the path must have a certain number of regions
  if (symbols.style == Panel::Style::HAS_STONES && _splitPoints.size() == 0)
    return generate_path_regions(
        std::min(symbols.getNum(Decoration::Stone),
                 (_panel->width() / 2 + _panel->height() / 2) / 2 + 1));

  if (symbols.style == Panel::Style::HAS_SHAPERS) {
    if (hasFlag(Config::SplitShapes)) {
      return generate_path_regions(symbols.getNum(Decoration::Poly) + 1);
    }
    return generate_path_length(_panel->get_num_grid_points() / 2);
  }

  return generate_path_length(_panel->get_num_grid_points() * 3 / 4);
}

// Generate a random path with the provided minimum length.
bool Generate::generate_path_length(int minLength, int maxLength) {
  int fails = 0;
  Point pos = adjust_point(pick_random(_starts));
  Point exit = adjust_point(pick_random(_exits));
  if (off_edge(pos) || off_edge(exit)) return false;
  set_path(pos);
  while (pos != exit) {
    if (fails++ > 20) return false;
    Point dir = pick_random(_DIRECTIONS2);
    Point newPos = pos + dir;
    Point directed = pos + dir / 2;
    if (off_edge(newPos) || hasSymbolOrPath(newPos) ||
        hasSymbolOrPath(directed) ||
        newPos == exit && _path.size() / 2 + 2 < minLength)
      continue;
    if (_panel->symmetry &&
        (off_edge(get_sym_point(newPos)) || newPos == get_sym_point(newPos)))
      continue;
    set_path(newPos);
    set_path(pos + dir / 2);
    pos = newPos;
    fails = 0;
  }
  return _path.size() / 2 + 1 >= minLength && _path.size() / 2 + 1 <= maxLength;
}

// Generate a path with the provided number of regions.
bool Generate::generate_path_regions(int minRegions) {
  int fails = 0;
  int regions = 1;
  Point pos = adjust_point(pick_random(_starts));
  Point exit = adjust_point(pick_random(_exits));
  if (off_edge(pos) || off_edge(exit)) return false;
  set_path(pos);
  while (pos != exit) {
    if (fails++ > 20) return false;
    Point dir = pick_random(_DIRECTIONS2);
    Point newPos = pos + dir;
    Point directed = pos + dir / 2;
    if (off_edge(newPos) || hasSymbolOrPath(newPos) ||
        hasSymbolOrPath(directed) || newPos == exit && regions < minRegions)
      continue;
    if (_panel->symmetry &&
        (off_edge(get_sym_point(newPos)) || newPos == get_sym_point(newPos)))
      continue;
    set_path(newPos);
    set_path(pos + dir / 2);
    if (!on_edge(newPos) && on_edge(pos)) {
      regions++;
      if (_panel->symmetry) regions++;
    }
    pos = newPos;
    fails = 0;
  }
  return regions >= minRegions;
}

// Generate a path that covers the maximum number of points.
bool Generate::generate_longest_path() {
  Point pos = adjust_point(pick_random(_starts));
  Point exit = adjust_point(pick_random(_exits));
  if (off_edge(pos) || off_edge(exit)) return false;
  Point block(-10, -10);
  if (hasFlag(Config::FalseParity)) {  // If false parity, one dot must be left
                                       // uncovered
    if (get_parity(pos + exit) == _panel->get_parity()) return false;
    block = Point(Random::rand() % (_panel->width() / 2 + 1) * 2,
                  Random::rand() % (_panel->height() / 2 + 1) * 2);
    while (pos == block || exit == block) {
      block = Point(Random::rand() % (_panel->width() / 2 + 1) * 2,
                    Random::rand() % (_panel->height() / 2 + 1) * 2);
    }
    set_path(block);
  } else if (get_parity(pos + exit) != _panel->get_parity())
    return false;
  int fails = 0;
  int reqLength =
      _panel->get_num_grid_points() + static_cast<int>(_path.size()) / 2;
  bool centerFlag = !on_edge(pos);
  set_path(pos);
  while (pos != exit && !(_panel->symmetry && get_sym_point(pos) == exit)) {
    std::vector<std::string> solution;  // For debugging only
    for (int y = 0; y < _panel->height(); y++) {
      std::string row;
      for (int x = 0; x < _panel->width(); x++) {
        if (get(x, y) == PATH) {
          row += "xx";
        } else
          row += "    ";
      }
      solution.push_back(row);
    }
    if (fails++ > 20) return false;
    Point dir = pick_random(_DIRECTIONS2);
    for (Point checkDir : _DIRECTIONS2) {
      Point check = pos + checkDir;
      if (off_edge(check) || hasSymbolOrPath(check)) continue;
      if (check == exit) continue;
      int open = 0;
      for (Point checkDir2 : _DIRECTIONS2) {
        Point added = check + checkDir2;
        if (!off_edge(added) && !hasSymbolOrPath(added)) {
          if (++open >= 2) break;
        }
      }
      if (open < 2) {
        dir = checkDir;
        break;
      }
    }
    Point newPos = pos + dir;
    Point directed = pos + dir / 2;
    // Various checks to see if going this direction will lead to any issues
    if (off_edge(newPos) || hasSymbolOrPath(newPos) ||
        hasSymbolOrPath(directed) ||
        newPos == exit && _path.size() / 2 + 3 < reqLength ||
        _panel->symmetry && get_sym_point(newPos) == exit &&
            _path.size() / 2 + 3 < reqLength)
      continue;
    if (_panel->symmetry &&
        (off_edge(get_sym_point(newPos)) || newPos == get_sym_point(newPos)))
      continue;
    Point added = newPos + dir;
    if (on_edge(newPos) && _panel->symmetry != Panel::Symmetry::Horizontal &&
        added != block && (off_edge(added) || hasSymbolOrPath(added))) {
      if (centerFlag && off_edge(added)) {
        centerFlag = false;
      } else {
        int open = 0;
        for (Point checkDir : _DIRECTIONS2) {
          Point extorted = newPos + checkDir;
          if (!off_edge(extorted) && !hasSymbolOrPath(extorted)) {
            if (++open >= 2) break;
          }
        }
        if (open >= 2) continue;
      }
    }
    set_path(newPos);
    set_path(pos + dir / 2);
    pos = newPos;
    fails = 0;
  }
  if (!off_edge(block))  // Uncover the one dot for false parity
    set(block, 0);
  return _path.size() / 2 + 1 == reqLength;
}

// Generate path that passes through all of the hitPoints in order
bool Generate::generate_special_path() {
  Point pos = adjust_point(pick_random(_starts));
  Point exit = adjust_point(pick_random(_exits));
  if (off_edge(pos) || off_edge(exit)) return false;
  set_path(pos);
  for (Point p : hitPoints) {
    set(p, PATH);
  }
  int hitIndex = 0;
  int minLength = _panel->get_num_grid_points() * 3 / 4;
  while (pos != exit) {
    std::vector<Point> validDir;
    for (Point dir : _DIRECTIONS2) {
      Point newPos = pos + dir;
      if (off_edge(newPos)) continue;
      Point connectPos = pos + dir / 2;
      // Go through the hit point if passing next to it
      if (get(connectPos) == PATH && hitIndex < hitPoints.size() &&
          connectPos == hitPoints[hitIndex]) {
        validDir = {dir};
        hitIndex++;
        break;
      }
      if (hasSymbolOrPath(newPos) || hasSymbolOrPath(connectPos) ||
          newPos == exit && (hitIndex != hitPoints.size() ||
                             _path.size() / 2 + 2 < minLength))
        continue;
      if (_panel->symmetry && newPos == get_sym_point(newPos)) continue;
      bool fail = false;
      for (Point dir : _DIRECTIONS1) {
        Point added = newPos + dir;
        if (!off_edge(added) && get(added) == PATH &&
            newPos + dir != hitPoints[hitIndex]) {
          fail = true;
          break;
        }
      }
      if (fail) continue;
      validDir.push_back(dir);
    }
    if (validDir.size() == 0) return false;
    Point dir = pick_random(validDir);
    set_path(pos + dir);
    set_path(pos + dir / 2);
    pos = pos + dir;
  }
  return hitIndex == hitPoints.size() && _path.size() >= minLength;
}

// Eerase the path from the puzzle grid
void Generate::erase_path() {
  /*_drawnPath.clear();
  _drawnPath.resize(_height);
  for (auto& row : _drawnPath) row.resize(_width);*/
  for (int x = 0; x < _panel->width(); x++) {
    for (int y = 0; y < _panel->height(); y++) {
      if (get(x, y) == PATH) set(x, y, 0);
    }
  }
}

// If a point is on an edge, bump it randomly to an adjacent vertex. Otherwise,
// the point is untouched
Point Generate::adjust_point(Point pos) {
  if (pos.first % 2 != 0) {
    if (hasSymbolOrPath(pos)) return {-10, -10};
    set_path(pos);
    return Point(pos.first - 1 + Random::rand() % 2 * 2, pos.second);
  }
  if (pos.second % 2 != 0) {
    if (hasSymbolOrPath(pos)) return {-10, -10};
    set_path(pos);
    return Point(pos.first, pos.second - 1 + Random::rand() % 2 * 2);
  }
  if (_panel->symmetry && _exits.count(pos) &&
      !_exits.count(get_sym_point(pos)))
    return {-10, -10};
  return pos;
}

// Get the set of points in region containing the point (pos)
std::set<Point> Generate::get_region(Point pos) {
  std::set<Point> region;
  std::vector<Point> check;
  check.push_back(pos);
  region.insert(pos);
  while (check.size() > 0) {
    Point p = check[check.size() - 1];
    check.pop_back();
    for (Point dir : _DIRECTIONS1) {
      Point p1 = p + dir;
      if (on_edge(p1)) continue;
      if (get(p1) == PATH || get(p1) == OPEN) continue;
      Point p2 = p + dir * 2;
      if ((get(p2) & Decoration::Empty) == Decoration::Empty) continue;
      if (region.insert(p2).second) {
        check.push_back(p2);
      }
    }
  }
  return region;
}

// Get all the symbols in the region containing including the point (pos)
std::vector<int> Generate::get_symbols_in_region(Point pos) {
  return get_symbols_in_region(get_region(pos));
}

// Get all the symbols in the given region
std::vector<int> Generate::get_symbols_in_region(
    const std::set<Point>& region) {
  std::vector<int> symbols;
  for (Point p : region) {
    if (get(p)) symbols.push_back(get(p));
  }
  return symbols;
}

// Place a start point in a random location
bool Generate::place_start(int amount) {
  _starts.clear();
  _panel->ClearStartpoints();
  while (amount > 0) {
    Point pos = Point(Random::rand() % (_panel->width() / 2 + 1) * 2,
                      Random::rand() % (_panel->height() / 2 + 1) * 2);
    if (hasFlag(Config::StartEdgeOnly)) switch (Random::rand() % 4) {
        case 0:
          pos.first = 0;
          break;
        case 1:
          pos.second = 0;
          break;
        case 2:
          pos.first = _panel->width() - 1;
          break;
        case 3:
          pos.second = _panel->height() - 1;
          break;
      }
    if (_parity != -1 && get_parity(pos) != (amount == 1 ? _parity : !_parity))
      continue;
    if (_starts.count(pos) || _exits.count(pos)) continue;
    if (_panel->symmetry && pos == get_sym_point(pos)) continue;
    // Highly discourage putting start points adjacent
    bool adjacent = false;
    for (Point dir : _DIRECTIONS2) {
      if (!off_edge(pos + dir) && get(pos + dir) == Decoration::Start) {
        adjacent = true;
        break;
      }
    }
    if (adjacent && Random::rand() % 10 > 0) continue;
    _starts.insert(pos);
    _panel->SetGridSymbol(pos.first, pos.second, Decoration::Start,
                          Decoration::Color::None);
    amount--;
    if (_panel->symmetry) {
      Point sp = get_sym_point(pos);
      _starts.insert(sp);
      _panel->SetGridSymbol(sp.first, sp.second, Decoration::Start,
                            Decoration::Color::None);
    }
  }
  return true;
}

// Place an exit point in a random location on the edge of the grid
bool Generate::place_exit(int amount) {
  _exits.clear();
  _panel->ClearExits();
  while (amount > 0) {
    Point pos = Point(Random::rand() % (_panel->width() / 2 + 1) * 2,
                      Random::rand() % (_panel->height() / 2 + 1) * 2);
    switch (Random::rand() % 4) {
      case 0:
        pos.first = 0;
        break;
      case 1:
        pos.second = 0;
        break;
      case 2:
        pos.first = _panel->width() - 1;
        break;
      case 3:
        pos.second = _panel->height() - 1;
        break;
    }
    if (_parity != -1 && (get_parity(pos) + _panel->get_parity()) % 2 !=
                             (amount == 1 ? _parity : !_parity))
      continue;
    if (_starts.count(pos) || _exits.count(pos)) continue;
    if (_panel->symmetry && pos == get_sym_point(pos)) continue;
    if (_panel->symmetry && get_sym_point(pos).first != 0 &&
        get_sym_point(pos).second != 0)
      continue;
    // Prevent putting exit points adjacent
    bool adjacent = false;
    for (Point dir : _8DIRECTIONS2) {
      if (!off_edge(pos + dir) && get(pos + dir) == Decoration::Exit) {
        adjacent = true;
        break;
      }
    }
    if (adjacent) continue;
    _exits.insert(pos);
    _panel->SetGridSymbol(pos.first, pos.second, Decoration::Exit,
                          Decoration::Color::None);
    amount--;
    if (_panel->symmetry) {
      Point sp = get_sym_point(pos);
      _exits.insert(sp);
      _panel->SetGridSymbol(sp.first, sp.second, Decoration::Exit,
                            Decoration::Color::None);
    }
  }
  return true;
}

// Check if a gap can be placed at pos.
bool Generate::can_place_gap(Point pos) {
  // Prevent putting open gaps at edges of the puzzle
  if (pos.first == 0 || pos.second == 0) {
    if (hasFlag(Config::FullGaps)) return false;
  } else if (Random::rand() % 2 == 0)
    return false;  // Encourages gaps on outside border
  // Prevent putting a gap on top of a start/end point
  if (_starts.count(pos) || _exits.count(pos)) return false;
  // For symmetry puzzles, prevent putting two gaps symmetrically opposite
  if (_panel->symmetry && (get_sym_point(pos) == pos) ||
      (get(get_sym_point(pos)) & Decoration::Gap))
    return false;
  if ((_panel->symmetry == Panel::Symmetry::ParallelH ||
       _panel->symmetry == Panel::Symmetry::ParallelHFlip) &&
      pos.second == _panel->height() / 2)
    return false;
  if ((_panel->symmetry == Panel::Symmetry::ParallelV ||
       _panel->symmetry == Panel::Symmetry::ParallelVFlip) &&
      pos.first == _panel->width() / 2)
    return false;
  if (_panel->symmetry == Panel::Symmetry::FlipNegXY &&
      (pos.first + pos.second == _width - 1 ||
       pos.first + pos.second == _width + 1))
    return false;
  if (_panel->symmetry == Panel::Symmetry::FlipXY &&
      (pos.first - pos.second == 1 || pos.first - pos.second == -1))
    return false;
  if (hasFlag(Config::FullGaps)) {  // Prevent forming dead ends with open gaps
    std::vector<Point> checkPoints =
        (pos.first % 2 == 0
             ? std::vector<Point>({Point(pos.first, pos.second - 1),
                                   Point(pos.first, pos.second + 1)})
             : std::vector<Point>({Point(pos.first - 1, pos.second),
                                   Point(pos.first + 1, pos.second)}));
    for (Point check : checkPoints) {
      int valid = 4;
      for (Point dir : _DIRECTIONS1) {
        Point p = check + dir;
        if (off_edge(p) || get(p) & GAP || get(p) == OPEN) {
          if (--valid <= 2) {
            return false;
          }
        }
      }
    }
  }
  return true;
}

// Place the given amount of gaps radomly around the puzzle
bool Generate::place_gaps(int amount) {
  std::set<Point> open;
  for (int y = 0; y < _panel->height(); y++) {
    for (int x = (y + 1) % 2; x < _panel->width(); x += 2) {
      if (get(x, y) == 0 && (!_fullGaps || !on_edge(Point(x, y)))) {
        open.emplace(Point(x, y));
      }
    }
  }

  while (amount > 0) {
    if (open.size() == 0) return false;
    Point pos = pick_random(open);
    if (can_place_gap(pos)) {
      set(pos, _fullGaps            ? static_cast<Decoration::Shape>(OPEN)
               : pos.first % 2 == 0 ? Decoration::Gap_Column
                                    : Decoration::Gap_Row);
      amount--;
    }
    open.erase(pos);
  }
  return true;
}

// Check if a dot can be placed at pos.
bool Generate::can_place_dot(Point pos, bool intersectionOnly) {
  if (get(pos) & DOT) return false;
  if (_panel->symmetry) {
    // For symmetry puzzles, make sure the current pos and symmetric pos are
    // both valid
    Point symPos = get_sym_point(pos);
    if (symPos == pos) return false;
    Panel::Symmetry backupSym = _panel->symmetry;
    _panel->symmetry = Panel::Symmetry::None;  // To prevent endless recursion
    // if (!can_place_dot(get_sym_point(pos))) {
    if (!can_place_dot(symPos, intersectionOnly)) {
      _panel->symmetry = backupSym;
      return false;
    }
    _panel->symmetry = backupSym;
  }
  if (_panel->symmetry == Panel::Symmetry::RotateLeft && _path1.count(pos) &&
      _path2.count(pos))
    return false;  // Prevent sharing of dots between symmetry lines
  if (hasFlag(Config::DisableDotIntersection)) return true;
  for (Point dir : _8DIRECTIONS1) {
    Point p = pos + dir;
    if (!off_edge(p) && (get(p) & DOT)) {
      // Don't allow adjacent dots
      if (dir.first == 0 || dir.second == 0) return false;
      // Allow diagonally adjacent placement some of the time
      if (Random::rand() % 2 > 0) return false;
    }
  }
  // Allow 2-space horizontal/vertical placement some of the time
  if (Random::rand() % (intersectionOnly ? 10 : 5) > 0) {
    for (Point dir : _DIRECTIONS2) {
      Point p = pos + dir;
      if (!off_edge(p) && (get(p) & DOT)) {
        return false;
      }
    }
  }
  return true;
}

// Place the given amount of dots at random points on the path
bool Generate::place_dots(int amount, int color, bool intersectionOnly) {
  if (_parity != -1) {  // For full dot puzzles, don't put dots on the starts
                        // and exits unless there are multiple
    for (int x = 0; x < _panel->width(); x += 2) {
      for (int y = 0; y < _panel->height(); y += 2) {
        if (_starts.size() == 1 && _starts.count(Point(x, y))) continue;
        if (_exits.size() == 1 && _exits.count(Point(x, y))) continue;
        if (!hasSymbolOrPath(x, y)) continue;
        set(x, y, Decoration::Dot_Intersection);
      }
    }
    amount -= _panel->get_num_grid_points();
    if (amount <= 0) return true;
    intersectionOnly = false;
    setFlagOnce(Config::DisableDotIntersection);
  }

  if (color == Decoration::Color::Blue || color == Decoration::Color::Cyan)
    color = IntersectionFlags::DOT_IS_BLUE;
  else if (color == Decoration::Color::Yellow ||
           color == Decoration::Color::Orange)
    color = IntersectionFlags::DOT_IS_ORANGE;
  else
    color = 0;

  std::set<Point> open = (color == 0                                  ? _path
                          : (color == IntersectionFlags::DOT_IS_BLUE) ? _path1
                                                                      : _path2);
  for (Point p : _starts) open.erase(p);
  for (Point p : _exits) open.erase(p);
  for (Point p : blockPos) open.erase(p);
  if (intersectionOnly) {
    std::set<Point> intersections;
    for (Point p : open) {
      if (p.first % 2 == 0 && p.second % 2 == 0) intersections.insert(p);
    }
    open = intersections;
  }
  if (hasFlag(Config::DisableDotIntersection)) {
    std::set<Point> intersections;
    for (Point p : open) {
      if (p.first % 2 != 0 || p.second % 2 != 0) intersections.insert(p);
    }
    open = intersections;
  }

  while (amount > 0) {
    if (open.size() == 0) return false;
    Point pos = pick_random(open);
    open.erase(pos);
    if (!can_place_dot(pos, intersectionOnly)) continue;
    Decoration::Shape symbol = (pos.first & 1) == 1 ? Decoration::Dot_Row
                               : (pos.second & 1) == 1
                                   ? Decoration::Dot_Column
                                   : Decoration::Dot_Intersection;
    set(pos, symbol | color);
    for (Point dir : _DIRECTIONS1) {
      open.erase(pos + dir);
    }  // If symmetry, set a flag to break the point symmetric to the dot
    if (_panel->symmetry) {
      Point sp = get_sym_point(pos);
      symbol = (sp.first & 1) == 1    ? Decoration::Dot_Row
               : (sp.second & 1) == 1 ? Decoration::Dot_Column
                                      : Decoration::Dot_Intersection;
      if (symbol != Decoration::Dot_Intersection)
        set(sp, symbol & ~Decoration::Dot);
      open.erase(sp);
      for (Point dir : _DIRECTIONS1) {
        open.erase(sp + dir);
      }
    }
    amount--;
  }
  return true;
}

// Check if a stone can be placed at pos.
bool Generate::can_place_stone(const std::set<Point>& region, int color) {
  for (Point p : region) {
    int sym = get(p);
    if (get_symbol_type(sym) == Decoration::Stone) return (sym & 0xf) == color;
  }
  return true;
}

// Place the given amount of stones with the given color
bool Generate::place_stones(int color, int amount) {
  std::set<Point> open = _openpos;
  std::set<Point>
      open2;  // Used to store open points removed from the first pass, to make
              // sure a stone is put in every non-adjacent region
  int passCount = 0;
  int originalAmount = amount;
  while (amount > 0) {
    if (open.size() == 0) {
      // Make sure there is room for the remaining stones and enough partitions
      // have been made (based on the grid size)
      if (open2.size() < amount ||
          _bisect &&
              passCount < std::min(originalAmount, (_panel->width() / 2 +
                                                    _panel->height() / 2 + 2) /
                                                       4))
        return false;
      // Put remaining stones wherever they will fit
      Point pos = pick_random(open2);
      set(pos, Decoration::Stone | color);
      _openpos.erase(pos);
      open2.erase(pos);
      amount--;
      continue;
    }
    Point pos = pick_random(open);
    std::set<Point> region = get_region(pos);
    if (!can_place_stone(region, color)) {
      for (Point p : region) {
        open.erase(p);
      }
      continue;
    }
    if (_stoneTypes > 2) {  // If more than two colors, group stones together,
                            // otherwise it takes too long to generate.
      open.clear();
      for (Point p : region) {
        if (_openpos.count(p)) open.insert(p);
      }
    }
    open.erase(pos);
    if (_panel->symmetry) {
      open.erase(get_sym_point(pos));
    }
    if (_stoneTypes == 2) {
      for (Point p : region) {
        if (open.erase(p)) open2.insert(p);
      }  // Remove adjacent regions from the open list
      for (Point p : region) {
        for (Point dir : _8DIRECTIONS2) {
          Point pos2 = p + dir;
          if (open.count(pos2) && !region.count(pos2)) {
            for (Point P : get_region(pos2)) {
              open.erase(P);
            }
          }
        }
      }
    }
    set(pos, Decoration::Stone | color);
    _openpos.erase(pos);
    amount--;
    passCount++;
  }
  _bisect = false;  // After placing one color, adjacent regions are allowed
  _stoneTypes--;
  return true;
}

// Generate a random shape. region - the region of points to choose from; points
// chosen will be removed. bufferRegion - points that may be chosen twice due to
// overlapping shapes; points will be removed from here before points in region.
// maxSize - the maximum size of the generated shape. Whether the points can be
// contiguous or not is determined by local variable _SHAPEDIRECTIONS
Shape Generate::generate_shape(std::set<Point>& region,
                               std::set<Point>& bufferRegion, Point pos,
                               int maxSize) {
  Shape shape;
  shape.insert(pos);
  if (!bufferRegion.erase(pos)) region.erase(pos);
  while (shape.size() < maxSize && region.size() > 0) {
    pos = pick_random(shape);
    int i = 0;
    for (; i < 10; i++) {
      Point dir = pick_random(_SHAPEDIRECTIONS);
      Point p = pos + dir;
      if (region.count(p) && !shape.count(p)) {
        shape.insert(p);
        if (!bufferRegion.erase(p)) region.erase(p);
        break;
      }
    }
    if (i == 10) return shape;
  }
  return shape;
}

// Get the integer representing the shape, accounting for whether it is rotated
// or negative. -1 rotation means a random rotation, depth is for controlling
// recursion and should be set to 0
int Generate::make_shape_symbol(Shape shape, bool rotated, bool negative,
                                int rotation, int depth) {
  int symbol = static_cast<int>(Decoration::Poly);
  if (rotated) {
    if (rotation == -1) {
      if (make_shape_symbol(shape, rotated, negative, 0, depth + 1) ==
          make_shape_symbol(shape, rotated, negative, 1, depth + 1))
        return 0;  // Check to make sure the shape is not the same when rotated
      rotation = Random::rand() % 4;
    }
    symbol |= Decoration::Can_Rotate;
    Shape newShape;  // Rotate shape points according to rotation
    for (Point p : shape) {
      switch (rotation) {
        case 0:
          newShape.insert(p);
          break;
        case 1:
          newShape.emplace(Point(p.second, -p.first));
          break;
        case 2:
          newShape.emplace(Point(-p.second, p.first));
          break;
        case 3:
          newShape.emplace(Point(-p.first, -p.second));
          break;
      }
    }
    shape = newShape;
  }
  if (negative) symbol |= Decoration::Negative;
  int xmin = INT_MAX, xmax = INT_MIN, ymin = INT_MAX, ymax = INT_MIN;
  for (Point p : shape) {
    if (p.first < xmin) xmin = p.first;
    if (p.first > xmax) xmax = p.first;
    if (p.second < ymin) ymin = p.second;
    if (p.second > ymax) ymax = p.second;
  }
  if (xmax - xmin > 6 ||
      ymax - ymin > 6) {  // Shapes cannot be more than 4 in width and height
    return 0;
  }
  // Translate to the corner and set bit flags (16 bits, 1 where a shape block
  // is present)
  for (Point p : shape) {
    symbol |= (1 << ((p.first - xmin) / 2 + (ymax - p.second) * 2)) << 16;
  }
  if (Random::rand() % 4 >
      0) {  // The generator makes a certain type of symbol way too often (2x2
            // square with another square attached), this makes it much less
            // frequent
    int type = symbol >> 16;
    if (type == 0x0331 || type == 0x0332 || type == 0x0037 || type == 0x0067 ||
        type == 0x0133 || type == 0x0233 || type == 0x0073 || type == 0x0076)
      return 0;
  }
  return symbol;
}

// Place the given amount of shapes with random colors selected from the color
// vectors. colors - colors for regular shapes, negativeColors - colors for
// negative shapes, amount - how many normal shapes numRotated - how many
// rotated shapes, numNegative - how many negative shapes
bool Generate::place_shapes(const std::vector<int>& colors,
                            const std::vector<int>& negativeColors, int amount,
                            int numRotated, int numNegative) {
  std::set<Point> open = _openpos;
  int shapeSize = hasFlag(Config::SmallShapes) ? 2
                  : hasFlag(Config::BigShapes) ? amount == 1 ? 8 : 6
                                               : 4;
  int targetArea = amount * shapeSize * 7 /
                   8;  // Average size must be at least 7/8 of the target size
  if (amount * shapeSize > _panel->get_num_grid_blocks())
    targetArea = _panel->get_num_grid_blocks();
  int originalAmount = amount;
  if (hasFlag(Generate::Config::MountainFloorH) &&
      _panel->width() ==
          9) {  // The 4 small puzzles shape size may vary depending on the path
    targetArea = 0;
    removeFlag(Generate::Config::MountainFloorH);
  }
  int totalArea = 0;
  int minx = _panel->width(), miny = _panel->height(), maxx = 0, maxy = 0;
  int colorIndex = Random::rand() % colors.size();
  int colorIndexN = Random::rand() % (negativeColors.size() + 1);
  bool shapesCanceled = false, shapesCombined = false, flatShapes = true;
  if (amount == 1) shapesCombined = true;
  while (amount > 0) {
    if (open.size() == 0) return false;
    Point pos = pick_random(open);
    std::set<Point> region = get_region(pos);
    std::set<Point> bufferRegion;
    std::set<Point> open2;  // Open points for just that region
    for (Point p : region) {
      if (open.erase(p)) open2.insert(p);
    }
    if (region.size() + totalArea == _panel->get_num_grid_blocks() &&
        targetArea != _panel->get_num_grid_blocks())
      continue;  // To prevent shapes from filling every grid point
    std::vector<Shape> shapes;
    std::vector<Shape> shapesN;
    int numShapesN = std::min(
        Random::rand() % (numNegative + 1),
        static_cast<int>(region.size()) /
            3);  // Negative blocks may be at max 1/3 of the regular blocks
    if (amount == 1) numShapesN = numNegative;
    if (numShapesN) {
      std::set<Point> regionN = _gridpos;
      int maxSize = static_cast<int>(region.size()) -
                    numShapesN * 3;  // Max size of negative shapes
      if (maxSize == 0) maxSize = 1;
      for (int i = 0; i < numShapesN; i++) {
        pos = pick_random(region);
        // Try to pick a random point adjacent to a shape
        for (int i = 0; i < 10; i++) {
          Point p = pos + pick_random(_SHAPEDIRECTIONS);
          if (regionN.count(p) && !region.count(p)) {
            pos = p;
            break;
          }
        }
        if (!regionN.count(pos)) return false;
        Shape shape = generate_shape(regionN, pos,
                                     std::min(Random::rand() % 3 + 1, maxSize));
        shapesN.push_back(shape);
        for (Point p : shape) {
          if (region.count(p))
            bufferRegion.insert(
                p);  // Buffer region stores overlap between shapes
          else
            region.insert(p);
        }
      }
    }
    int numShapes =
        static_cast<int>(region.size() + bufferRegion.size()) /
            (shapeSize + 1) +
        1;  // Pick a number of shapes to make. I tried different ones until I
            // found something that made a good variety of shapes
    if (numShapes == 1 && bufferRegion.size() > 0)
      numShapes++;  // If there is any overlap, we need at least two shapes
    if (numShapes < amount && region.size() > shapeSize &&
        Random::rand() % 2 == 1)
      numShapes++;  // Adds more variation to the shape sizes
    if (region.size() <= shapeSize + 1 && bufferRegion.size() == 0 &&
        Random::rand() % 2 == 1)
      numShapes = 1;  // For more variation, sometimes make a bigger shape than
                      // the target if the size is close
    if (hasFlag(Config::MountainFloorH)) {
      if (region.size() < 19) continue;
      numShapes = 6;  // The big mountain floor puzzle on hard mode needs
                      // additional shapes since some combine
      targetArea = 19;
    }
    if (hasFlag(Config::SplitShapes) && numShapes != 1) continue;
    if (hasFlag(Config::RequireCombineShapes) && numShapes == 1) continue;
    bool balance = false;
    if (numShapes >
        amount  // The region is too big for the number of shapes chosen
    ) {
      if (numNegative < 2 || hasFlag(Config::DisableCancelShapes)) continue;
      // Make balancing shapes - Positive and negative will be switched so that
      // code can be reused
      balance = true;
      std::set<Point> regionN = _gridpos;
      numShapes = std::max(
          2, Random::rand() % numNegative + 1);  // Actually the negative shapes
      numShapesN = std::min(amount, 1);          // Actually the positive shapes
      if (numShapesN >= numShapes * 3 || numShapesN * 5 <= numShapes) continue;
      shapes.clear();
      shapesN.clear();
      region.clear();
      bufferRegion.clear();
      for (int i = 0; i < numShapesN; i++) {
        Shape shape =
            generate_shape(regionN, pick_random(regionN),
                           std::min(shapeSize + 1, numShapes * 2 / numShapesN +
                                                       Random::rand() % 3 - 1));
        shapesN.push_back(shape);
        for (Point p : shape) {
          region.insert(p);
        }
      }
      shapesCanceled = true;
      // Let the rest of the algorithm create the cancelling shapes
    }
    if (_panel->symmetry && numShapes == originalAmount && numShapes >= 3 &&
        !region.count(Point((_panel->width() / 4) * 2 + 1,
                            (_panel->height() / 4) * 2 + 1)))
      continue;  // Prevent it from shoving all shapes to one side of symmetry
    if ((_panel->symmetry == Panel::Symmetry::ParallelH ||
         _panel->symmetry == Panel::Symmetry::ParallelV ||
         _panel->symmetry == Panel::Symmetry::ParallelHFlip ||
         _panel->symmetry == Panel::Symmetry::ParallelVFlip) &&
        region.count(Point((_panel->width() / 4) * 2 + 1,
                           (_panel->height() / 4) * 2 + 1)))
      continue;  // Prevent parallel symmetry from making regions through the
                 // center line (this tends to make the puzzles way too hard)
    if (!balance && numShapesN &&
        (numShapesN > 1 && numRotated > 0 || numShapesN > 2 ||
         numShapes + numShapesN > 6))
      continue;  // Trying to prevent the game's shape calculator from lagging
                 // too much
    if (!(hasFlag(Config::MountainFloorH) && _panel->width() == 11) &&
        open2.size() < numShapes + numShapesN)
      continue;  // Not enough space to put the symbols
    if (numShapes == 1) {
      shapes.push_back(region);
      region.clear();
    } else
      for (; numShapes > 0; numShapes--) {
        if (region.size() == 0) break;
        Shape shape =
            generate_shape(region, bufferRegion, pick_random(region),
                           balance ? Random::rand() % 3 + 1 : shapeSize);
        if (!balance && numShapesN)
          for (Shape s : shapesN)
            if (std::equal(shape.begin(), shape.end(), s.begin(), s.end()))
              return false;  // Prevent unintentional in-group canceling
        shapes.push_back(shape);
      }
  // Take remaining area and try to stick it to existing shapes
  multibreak:
    while (region.size() > 0) {
      pos = pick_random(region);
      for (Shape& shape : shapes) {
        if (shape.size() > shapeSize || shape.count(pos) > 0) continue;
        for (Point p : shape) {
          for (Point dir : _DIRECTIONS2) {
            if (pos + dir == p) {
              shape.insert(pos);
              if (!bufferRegion.erase(pos)) region.erase(pos);
              goto multibreak;
            }
          }
        }
      }
      // Failed to cover entire region, need to pick a different region
      break;
    }
    if (region.size() > 0) continue;
    if (balance) {  // Undo swap for balancing shapes
      std::swap(shapes, shapesN);
    }
    numShapes = static_cast<int>(shapes.size());
    for (Shape& shape : shapesN) {
      shapes.push_back(shape);
    }
    if (hasFlag(Config::DisconnectShapes)) {
      // Make sure at least one shape is disconnected
      bool disconnect = false;
      for (Shape& shape : shapes) {
        if (shape.size() == 1) continue;
        disconnect = true;
        for (Point p : shape) {
          for (Point dir : _DIRECTIONS2) {
            if (shape.count(p + dir)) {
              disconnect = false;
              break;
            }
          }
          if (!disconnect) break;
        }
        if (disconnect) break;
      }
      if (!disconnect) continue;
    }
    if (numShapes > 1) shapesCombined = true;
    numNegative -= static_cast<int>(shapesN.size());
    if (hasFlag(Generate::Config::MountainFloorH) &&
        amount ==
            6) {  // For mountain floor, combine some of the shapes together
      if (!combine_shapes(shapes) ||
          !combine_shapes(
              shapes))  // Must call this twice b/c there are two combined areas
        return false;
      amount -= 2;
    }
    for (Shape& shape : shapes) {
      int symbol =
          make_shape_symbol(shape, (numRotated-- > 0), (numShapes-- <= 0));
      if (symbol == 0) return false;
      if (!((symbol >> 16) == 0x000F || (symbol >> 16) == 0x1111))
        flatShapes = false;
      // Attempt not to put shape symbols adjacent
      Point pos;
      for (int i = 0; i < 10; i++) {
        if (open2.size() == 0) return false;
        pos = pick_random(open2);
        bool pass = true;
        for (Point dir : _8DIRECTIONS2) {
          Point p = pos + dir;
          if (!off_edge(p) && get(p) & Decoration::Poly) {
            pass = false;
            break;
          }
        }
        if (pass) break;
      }
      if (symbol & Decoration::Negative)
        set(pos,
            symbol | negativeColors[(colorIndexN++) % negativeColors.size()]);
      else {
        set(pos, symbol | colors[(colorIndex++) % colors.size()]);
        totalArea += static_cast<int>(shape.size());
        amount--;
      }
      open2.erase(pos);
      _openpos.erase(pos);
      if (_panel->symmetry && originalAmount >= 3) {
        for (const Point& p : shape) {
          if (p.first < minx) minx = p.first;
          if (p.second < miny) miny = p.second;
          if (p.first > maxx) maxx = p.first;
          if (p.second > maxy) maxy = p.second;
        }
      }
    }
  }  // Do some final checks - make sure targetArea has been reached, all shapes
     // have been placed, and that config requirements have been met
  if (totalArea < targetArea || numNegative > 0 ||
      hasFlag(Config::RequireCancelShapes) && !shapesCanceled ||
      hasFlag(Config::RequireCombineShapes) && !shapesCombined ||
      originalAmount > 1 && flatShapes)
    return false;
  // If symmetry, make sure it didn't shove all the shapes to one side
  if (_panel->symmetry && originalAmount >= 3 &&
      (minx >= _panel->width() / 2 || maxx <= _panel->width() / 2 ||
       miny >= _panel->height() / 2 || maxy <= _panel->height() / 2))
    return false;
  return true;
}

// Count the occurrence of the given symbol color in the given region (for the
// stars)
int Generate::count_color(const std::set<Point>& region, int color) {
  int count = 0;
  for (Point p : region) {
    int sym = get(p);
    if (sym && (sym & 0xf) == color)
      if (count++ == 2) return count;
  }
  return count;
}

// Place the given amount of stars with the given color
bool Generate::place_stars(int color, int amount) {
  std::set<Point> open = _openpos;
  while (amount > 0) {
    if (open.size() == 0) return false;
    Point pos = pick_random(open);
    std::set<Point> region = get_region(pos);
    std::set<Point> open2;  // All of the open points in that region
    for (Point p : region) {
      if (open.erase(p)) open2.insert(p);
    }
    int count = count_color(region, color);
    if (count >= 2) continue;  // Too many of that color
    if (open2.size() + count < 2)
      continue;  // Not enough space to get 2 of that color
    if (count == 0 && amount == 1)
      continue;  // If one star is left, it needs a pair
    set(pos, Decoration::Star | color);
    _openpos.erase(pos);
    amount--;
    if (count == 0) {  // Add a second star of the same color
      open2.erase(pos);
      if (open2.size() == 0) return false;
      pos = pick_random(open2);
      set(pos, Decoration::Star | color);
      _openpos.erase(pos);
      amount--;
    }
  }
  return true;
}

// Check if there is a star in the given region
bool Generate::has_star(const std::set<Point>& region, int color) {
  for (Point p : region) {
    if (get(p) == (Decoration::Star | color)) return true;
  }
  return false;
}

bool Generate::checkStarZigzag() {
  if (_panel->width() <= 5 || _panel->height() <= 5) return true;
  for (int y = 1; y < _panel->height(); y += 2) {
    std::map<int, int> colorCount;
    for (int x = 1; x < _panel->width(); x += 2) {
      int color = get(x, y);
      if (color == 0) continue;
      if (!colorCount.count(color)) colorCount[color] = 0;
      colorCount[color] += 1;
    }
    for (std::pair<int, int> count : colorCount)
      if (count.second % 2 != 0) return true;
  }
  return false;
}

// Place the given amount of triangles with the given color. targetCount is how
// many triangles are in the symbol, or 0 for random
bool Generate::place_triangles(int color, int amount, int targetCount) {
  /*if (_panel->id == 0x033EA) {  // Keep Yellow Pressure Plate
    int count = count_sides({1, 3});
    set({1, 3}, Decoration::Triangle | (count << 16) | color);
    _openpos.erase({1, 3});
  }*/
  std::set<Point> open = _openpos;
  int count1 = 0, count2 = 0, count3 = 0;
  while (amount > 0) {
    if (open.size() == 0) return false;
    Point pos = pick_random(open);
    int count = count_sides(pos);
    open.erase(pos);
    if (_panel->symmetry) {
      open.erase(get_sym_point(pos));
    }
    if (count == 0 || targetCount && count != targetCount) continue;
    if (hasFlag(Config::TreehouseLayout) /*||
        _panel->id == 0x289E7*/) {  // If the block is adjacent to a start or
                                  // exit, don't place a triangle there
      bool found = false;
      for (Point dir : _DIRECTIONS1) {
        if (_starts.count(pos + dir) || _exits.count(pos + dir)) {
          found = true;
          break;
        }
      }
      if (found) continue;
    }
    if (count == 1) {
      if (!targetCount && count1 * 2 > count2 + count3 &&
          Random::rand() % 2 == 0)
        continue;
      count1++;
    }
    if (count == 2) {
      if (!targetCount && count2 * 2 > count1 + count3 &&
          Random::rand() % 2 == 0)
        continue;
      count2++;
    }
    if (count == 3) {
      if (!targetCount && count3 * 2 > count1 + count2 &&
          Random::rand() % 2 == 0)
        continue;
      count3++;
    }
    set(pos, Decoration::Triangle | (count << 16) | color);
    _openpos.erase(pos);
    amount--;
  }
  return true;
}

// Count how many sides are touched by the line (for the triangles)
int Generate::count_sides(Point pos) {
  int count = 0;
  for (Point dir : _DIRECTIONS1) {
    Point p = pos + dir;
    if (!off_edge(p) && get(p) == PATH) {
      count++;
    }
  }
  return count;
}

// Place the given amount of arrows with the given color. targetCount is how
// many ticks on the arrows, or 0 for random The color won't actually be
// reflected, ArrowRecolor must be used instead
bool Generate::place_arrows(int color, int amount, int targetCount) {
  std::set<Point> open = _openpos;
  while (amount > 0) {
    if (open.size() == 0) return false;
    Point pos = pick_random(open);
    open.erase(pos);
    if (pos.first == _panel->width() / 2)
      continue;  // Because of a glitch where arrows in the center column won't
                 // draw right
    int fails = 0;
    while (fails++ < 20) {  // Keep picking random directions until one works
      int choice = (_parity == -1 ? Random::rand() % 8 : Random::rand() % 4);
      Point dir = _8DIRECTIONS2[choice];
      int count = count_crossings(pos, dir);
      if (count == 0 || count > 3 || targetCount && count != targetCount)
        continue;
      if (dir.first < 0 && count == (pos.first + 1) / 2 ||
          dir.first > 0 && count == (_panel->width() - pos.first) / 2 ||
          dir.second < 0 && count == (pos.second + 1) / 2 ||
          dir.second > 0 && count == (_panel->height() - pos.second) / 2 &&
              Random::rand() % 10 > 0)
        continue;  // Make it so that there will be some possible edges that
                   // aren't passed, in the vast majority of cases
      //_panel->SetGridSymbol(pos, Decoration::Arrow | color | (count << 12) |
      //(choice << 16));
      _openpos.erase(pos);
      amount--;
      break;
    }
  }
  return true;
}

// Count the number of times the given vector is passed through (for the arrows)
int Generate::count_crossings(Point pos, Point dir) {
  pos = pos + dir / 2;
  int count = 0;
  while (!off_edge(pos)) {
    if (get(pos) == PATH) count++;
    pos = pos + dir;
  }
  return count;
}

// Place the given amount of erasers with the given colors. eraseSymbols are the
// symbols that were erased
bool Generate::place_erasers(const std::vector<int>& colors,
                             const std::vector<int>& eraseSymbols) {
  std::set<Point> open = _openpos;
  /*if (_panel->id == 0x288FC && hasFlag(Generate::Config::DisableWrite))
    open.erase({5, 5});  // For the puzzle in the cave with a pillar in middle*/
  int amount = static_cast<int>(colors.size());
  while (amount > 0) {
    if (open.size() == 0) return false;
    int toErase = eraseSymbols[amount - 1];
    int color = colors[amount - 1];
    Point pos = pick_random(open);
    std::set<Point> region = get_region(pos);
    std::set<Point> open2;
    for (Point p : region) {
      if (open.erase(p)) open2.insert(p);
    }
    if (_splitPoints.size() >
        0) {  // Make sure this is one of the split point regions
      bool found = false;
      for (Point p : _splitPoints) {
        if (region.count(p)) {
          found = true;
          break;
        }
      }
      if (!found) continue;
    }
    /*if (_panel->id == 0x288FC && hasFlag(Generate::Config::DisableWrite) &&
        !region.count({5, 5}))
      continue;  // For the puzzle in the cave with a pillar in middle*/
    if (hasFlag(Config::MakeStonesUnsolvable)) {
      std::set<Point> valid;
      for (Point p : open2) {
        // Try to make a checkerboard pattern with the stones
        if (!off_edge(p + Point(2, 2)) && get(p + Point(2, 2)) == toErase &&
                get(p + Point(0, 2)) != 0 && get(p + Point(0, 2)) != toErase &&
                get(p + Point(2, 0)) != 0 && get(p + Point(2, 0)) != toErase ||
            !off_edge(p + Point(-2, 2)) && get(p + Point(-2, 2)) == toErase &&
                get(p + Point(0, 2)) != 0 && get(p + Point(0, 2)) != toErase &&
                get(p + Point(-2, 0)) != 0 &&
                get(p + Point(-2, 0)) != toErase ||
            !off_edge(p + Point(2, -2)) && get(p + Point(2, -2)) == toErase &&
                get(p + Point(0, -2)) != 0 &&
                get(p + Point(0, -2)) != toErase && get(p + Point(2, 0)) != 0 &&
                get(p + Point(2, 0)) != toErase ||
            !off_edge(p + Point(-2, -2)) && get(p + Point(-2, -2)) == toErase &&
                get(p + Point(0, -2)) != 0 &&
                get(p + Point(0, -2)) != toErase &&
                get(p + Point(-2, 0)) != 0 && get(p + Point(-2, 0)) != toErase)
          valid.insert(p);
      }
      open2 = valid;
    }
    if ((open2.size() == 0 || _splitPoints.size() == 0 && open2.size() == 1) &&
        !(toErase & Decoration::Dot))
      continue;
    bool canPlace = false;
    if (get_symbol_type(toErase) == Decoration::Stone) {
      canPlace = !can_place_stone(region, (toErase & 0xf));
    } else if (get_symbol_type(toErase) == Decoration::Star) {
      canPlace = (count_color(region, (toErase & 0xf)) +
                      (color == (toErase & 0xf) ? 1 : 0) !=
                  1);
    } else
      canPlace = true;
    if (!canPlace) continue;

    if (get_symbol_type(toErase) == Decoration::Stone ||
        get_symbol_type(toErase) == Decoration::Star) {
      set(pos, toErase);
    } else if (toErase &
               Decoration::Dot) {  // Find an open edge to put the dot on
      std::set<Point> openEdge;
      for (Point p : region) {
        for (Point dir : _8DIRECTIONS1) {
          if (toErase == Decoration::Dot_Intersection &&
              (dir.first == 0 || dir.second == 0))
            continue;
          Point p2 = p + dir;
          if (!hasSymbolOrPath(p2) &&
              (hasFlag(Config::FalseParity) || can_place_dot(p2, false))) {
            openEdge.insert(p2);
          }
        }
      }
      if (openEdge.size() == 0) continue;
      pos = pick_random(openEdge);
      toErase &= ~IntersectionFlags::INTERSECTION;
      if ((toErase & 0xf) == Decoration::Color::Blue ||
          (toErase & 0xf) == Decoration::Color::Cyan)
        toErase |= IntersectionFlags::DOT_IS_BLUE;
      if ((toErase & 0xf) == Decoration::Color::Yellow ||
          (toErase & 0xf) == Decoration::Color::Orange)
        toErase |= IntersectionFlags::DOT_IS_ORANGE;
      toErase &= ~0x4000f;  // Take away extra flags from the symbol
      if ((pos.first & 1) == 0 && (pos.second & 1) == 0)
        toErase |= Decoration::Dot_Intersection;
      else if ((pos.second & 1) == 0)
        toErase |= Decoration::Dot_Row;
      set(pos, ((pos.first & 1) == 1    ? Decoration::Dot_Row
                : (pos.second & 1) == 1 ? Decoration::Dot_Column
                                        : Decoration::Dot_Intersection) |
                   (toErase & 0xffff));
    } else if (get_symbol_type(toErase) == Decoration::Poly) {
      int symbol = 0;  // Make a random shape to cancel
      while (symbol == 0) {
        std::set<Point> area = _gridpos;
        int shapeSize;
        if ((toErase & Decoration::Negative) || hasFlag(Config::SmallShapes))
          shapeSize = Random::rand() % 3 + 1;
        else {
          shapeSize = Random::rand() % 5 + 1;
          if (shapeSize < 3) shapeSize += Random::rand() % 3;
        }
        Shape shape = generate_shape(area, pick_random(area), shapeSize);
        if (shape.size() == region.size())
          continue;  // Don't allow the shape to match the region, to guarantee
                     // it will be wrong
        symbol = make_shape_symbol(shape, toErase & Decoration::Can_Rotate,
                                   toErase & Decoration::Negative);
      }
      set(pos, symbol | (toErase & 0xf));
    } else if (get_symbol_type(toErase) == Decoration::Triangle) {
      if (hasFlag(Config::TreehouseLayout) /*||
          _panel->id == 0x289E7*/) {  // If the block is adjacent to a start or
                                    // exit, don't place a triangle there
        bool found = false;
        for (Point dir : _DIRECTIONS1) {
          if (_starts.count(pos + dir) || _exits.count(pos + dir)) {
            found = true;
            break;
          }
        }
        if (found) continue;
      }
      int count = count_sides(pos);
      if (count == 0)
        count = Random::rand() % 3 + 1;
      else
        count = (count + (Random::rand() & 1)) % 3 + 1;
      set(pos, toErase | (count << 16));
    }

    if (!(toErase & Decoration::Dot)) {
      _openpos.erase(pos);
      open2.erase(pos);
    }
    // Place the eraser at a random open point
    if (_splitPoints.size() == 0)
      pos = pick_random(open2);
    else
      for (Point p : _splitPoints)
        if (region.count(p)) {
          pos = p;
          break;
        }
    /*if (_panel->id == 0x288FC && hasFlag(Generate::Config::DisableWrite)) {
      if (hasSymbolOrPath(5, 5)) return false;
      pos = {5, 5};  // For the puzzle in the cave with a pillar in middle
    }*/
    set(pos, Decoration::Eraser | color);
    _openpos.erase(pos);
    amount--;
  }
  return true;
}

// For the mountain floor puzzle on hard mode. Combine two tetris shapes into
// one
bool Generate::combine_shapes(std::vector<Shape>& shapes) {
  for (int i = 0; i < shapes.size(); i++) {
    for (int j = 0; j < shapes.size(); j++) {
      if (i == j) continue;
      if (shapes[i].size() + shapes[j].size() <= 5) continue;
      if (shapes[i].size() > 5 || shapes[j].size() > 5) continue;
      // Look for adjacent points
      for (Point p1 : shapes[i]) {
        for (Point p2 : shapes[j]) {
          for (Point dir : _DIRECTIONS2) {
            if (p1 + dir == p2) {
              // Combine shapes
              for (Point p : shapes[i]) shapes[j].insert(p);
              // Make sure there are no holes
              std::set<Point> area = _gridpos;
              for (Point p : shapes[j]) area.erase(p);
              while (area.size() > 0) {
                std::set<Point> region;
                std::vector<Point> check;
                check.push_back(*area.begin());
                region.insert(*area.begin());
                while (check.size() > 0) {
                  Point p = check[check.size() - 1];
                  check.pop_back();
                  for (Point dir : _DIRECTIONS1) {
                    Point p2 = p + dir * 2;
                    if (area.count(p2) && region.insert(p2).second) {
                      check.push_back(p2);
                    }
                  }
                }
                bool connected = false;
                for (Point p : region) {
                  if (p.first == 1 || p.second == 1 ||
                      p.first == _panel->width() - 2 ||
                      p.second == _panel->height() - 2) {
                    connected = true;
                    break;
                  }
                }
                if (!connected) return false;
                for (Point p : region) area.erase(p);
              }
              shapes.erase(shapes.begin() + i);
              return true;
            }
          }
        }
      }
    }
  }
  return false;
}

bool Generate::hasSymbolOrPath(int x, int y) { return get(x, y) != 0; }

std::string Generate::AsCode() { return _panel->Write(); }