import { gameBoard } from "./gameBoard.js";

export const knightMoves = (origin, destination) => {
  // make board - 8 x 8
  const board = gameBoard(8);
  // initialize origin square -- origin[0] is x, origin[1] is y
  const originSquare = board.find(origin[0], origin[1]);
  // exit out if the origin square is off the game board
  if (!originSquare) return console.log("No such starting square possible!");
  // otherwise, continue initialization
  originSquare.visited = true;
  // set search iteration level to '0'
  originSquare.level = 0;
  // possible move combinations for x and y - linked at index values - moves clockwise
  const possibleX = [1, 2, 2, 1, -1, -2, -2, -1];
  const possibleY = [2, 1, -1, -2, -2, -1, 1, 2];
  // formatter for final output
  const format = (moves) => {
    // fix the output array by traversing provided array of BFS search results
    // get last square (the destination)
    let square = moves[moves.length - 1];
    // loop through previous squares until there are no more previous squares (the origin)
    // get array of path - made changeable for later
    let arr = [];
    while (square != null) {
      arr.unshift(square);
      square = square.prev;
    }
    // format the output string in the Odin-approved way
    let output = `=> You made it in ${
      arr.length - 1
    } moves! Here's your path:\n`;
    // loop through returned array of square objects to return array of positions and append them to the output
    for (let i = 0; i < arr.length; i++) {
      // change each array index to be the position of the current square object
      arr[i] = new Array(arr[i].x, arr[i].y);
      // then add it to the output string
      output = `${output} [${arr[i]}]\n`;
    }
    return console.log(output);
  };
  // initialize looping variables
  let current;
  const queue = [originSquare];
  const searchMoves = [];
  // while there are squares in the queue
  while (queue.length > 0) {
    // get first queued square and remove it from queue
    current = queue.shift();
    // add to search moves array
    searchMoves.push(current);
    // if values match, return
    if (current.x === destination[0] && current.y === destination[1])
      return format(searchMoves);
    // otherwise - eight possible moves can be made
    for (let i = 0; i < 8; i++) {
      // assigns values to possible move combinations at index
      const x = current.x + possibleX[i];
      const y = current.y + possibleY[i];
      // then checks them
      const found = board.find(x, y);
      if (found) {
        if (!found.visited) {
          // initializes square and pushes to queue
          found.visited = true;
          found.level = current.level + 1;
          found.prev = current;
          queue.push(found);
        }
      }
    }
  }
  // if not found, return infinity
  return Infinity;
};