const DEFAULT_MAP_WIDTH = 1000;
const DEFAULT_MAP_HEIGHT = 700;
const STARTER_GAP = 28;
const STARTER_MIN_OBJECT_WIDTH = 120;
const STARTER_MIN_OBJECT_HEIGHT = 80;
const STARTER_TARGET_ROW_HEIGHT = 210;

function toPositiveInteger(value, fallback) {
  const parsed = Number.parseInt(String(value), 10);
  return Number.isInteger(parsed) && parsed > 0 ? parsed : fallback;
}

function roundToTwo(value) {
  return Math.round(value * 100) / 100;
}

function getStarterGrid(zones) {
  const zoneCount = Array.isArray(zones) ? zones.length : 0;
  const columnCount = zoneCount <= 4 ? 2 : 3;
  const rowCount = Math.ceil(Math.max(zoneCount, 1) / columnCount);
  return { columnCount, rowCount };
}

function getStarterMapSize(zones, mapSize = {}) {
  const { columnCount, rowCount } = getStarterGrid(zones);
  const currentWidth = toPositiveInteger(mapSize.width, DEFAULT_MAP_WIDTH);
  const currentHeight = toPositiveInteger(mapSize.height, DEFAULT_MAP_HEIGHT);
  const requiredWidth =
    columnCount * STARTER_MIN_OBJECT_WIDTH + STARTER_GAP * (columnCount + 1);
  const minimumGridHeight =
    rowCount * STARTER_MIN_OBJECT_HEIGHT + STARTER_GAP * (rowCount + 1);
  const preferredGridHeight = rowCount * STARTER_TARGET_ROW_HEIGHT;

  return {
    width: Math.max(currentWidth, requiredWidth),
    height: Math.max(currentHeight, minimumGridHeight, preferredGridHeight),
  };
}

function buildStarterObjectsFromZones(zones, width, height) {
  if (!Array.isArray(zones) || !zones.length) return [];

  const mapSize = getStarterMapSize(zones, { width, height });
  const { columnCount, rowCount } = getStarterGrid(zones);
  const cellWidth = (mapSize.width - STARTER_GAP * (columnCount + 1)) / columnCount;
  const cellHeight = (mapSize.height - STARTER_GAP * (rowCount + 1)) / rowCount;

  return zones.map((zone, index) => {
    const column = index % columnCount;
    const row = Math.floor(index / columnCount);
    return {
      zone_id: zone.id,
      type: "zone",
      label: zone.name,
      x: roundToTwo(STARTER_GAP + column * (cellWidth + STARTER_GAP)),
      y: roundToTwo(STARTER_GAP + row * (cellHeight + STARTER_GAP)),
      width: Math.max(STARTER_MIN_OBJECT_WIDTH, roundToTwo(cellWidth)),
      height: Math.max(STARTER_MIN_OBJECT_HEIGHT, roundToTwo(cellHeight)),
      rotation: 0,
      locked: false,
      visible: true,
      sort_order: index + 1,
      metadata_json: { starter: true },
    };
  });
}

module.exports = {
  buildStarterObjectsFromZones,
  getStarterMapSize,
};