/**
 * Copyright (C) 2023  Shuang Chen

  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see <http://www.gnu.org/licenses/>.

  -----------------------------------------------------------------------
  
  Modified by Isaac Vega <isaacvega1996@gmail.com>
 */

import { acycle, coord, fillFacelet, get8Perm, rn, set8Perm, Solver } from "../lib/mathlib";
import { regScrambler } from "./scramble";

/*
x504x x x504x
	132 231 132
	x x405x x
		x504x
			132
			x  */
const cFacelet = [
  [3, 16, 11], // F3, L4, R5
  [4, 23, 15], // F4, D5, L3
  [5, 9, 22], // F5, R3, D4
  [10, 17, 21], // R4, L5, D3
];

const eFacelet = [
  [1, 7], // F1, R1
  [2, 14], // F2, L2
  [0, 18], // F0, D0
  [6, 12], // R0, L0
  [8, 20], // R2, D2
  [13, 19], // L1, D1
];

function checkNoBar(perm, ori) {
  const edgeOri = eocoord.set([], ori & 0x1f);
  const cornOri = cocoord.set([], ori >> 5);
  const edgePerm = epcoord.set([], perm);
  const f = [];
  fillFacelet(cFacelet, f, [0, 1, 2, 3], cornOri, 6);
  fillFacelet(eFacelet, f, edgePerm, edgeOri, 6);
  const pieces = [4, 2, 3, 1, 5, 0];
  for (let i = 0; i < 6; i++) {
    for (let j = 0; j < 2; j++) {
      const p1 = eFacelet[i][0 ^ j];
      const p2 = eFacelet[i][1 ^ j];
      const nb1 = ~~(p1 / 6) * 6 + pieces[(pieces.indexOf(p1 % 6) + 5) % 6];
      const nb2 = ~~(p2 / 6) * 6 + pieces[(pieces.indexOf(p2 % 6) + 1) % 6];
      if (f[nb1] == f[p1] && f[nb2] == f[p2]) {
        return false;
      }
    }
  }
  return true;
}

const solv = new Solver(4, 2, [
  [0, [epermMove, "p", 6, -1], 360],
  [0, oriMove, 2592],
]);

const movePieces = [
  [0, 1, 3],
  [1, 2, 5],
  [0, 4, 2],
  [3, 5, 4],
];

const moveOris = [
  [0, 1, 0, 2],
  [0, 1, 0, 2],
  [0, 0, 1, 2],
  [0, 0, 1, 2],
];

function epermMove(arr, m) {
  acycle(arr, movePieces[m]);
}

const eocoord = new coord("o", 6, -2);
const epcoord = new coord("p", 6, -1);
const cocoord = new coord("o", 4, 3);

function oriMove(a, c) {
  const edgeOri = eocoord.set([], a & 0x1f);
  const cornOri = cocoord.set([], a >> 5);
  cornOri[c]++;
  acycle(edgeOri, movePieces[c], 1, moveOris[c]);
  return (cocoord.get(cornOri) << 5) | eocoord.get(edgeOri);
}

function getScramble(type) {
  const minl = type == "pyro" ? 0 : 8;
  const limit = type == "pyrl4e" ? 2 : 7;
  let len = 0;
  let sol;
  let perm;
  let ori;
  do {
    if (type == "pyro" || type == "pyrso" || type == "pyr4c") {
      perm = rn(360);
      ori = rn(2592);
    } else if (type == "pyrl4e") {
      perm = get8Perm(set8Perm([], rn(12), 4, -1).concat([4, 5]), 6, -1);
      ori = rn(3) * 864 + rn(8);
    } else if (type == "pyrnb") {
      do {
        perm = rn(360);
        ori = rn(2592);
      } while (!checkNoBar(perm, ori));
    }
    len = solv.search([perm, ori], 0).length;
    sol = solv.toStr(solv.search([perm, ori], minl).reverse(), "ULRB", ["'", ""]) + " ";
    for (let i = 0; i < 4; i++) {
      const r = rn(type == "pyr4c" ? 2 : 3);
      if (r < 2) {
        sol += "lrbu".charAt(i) + [" ", "' "][r];
        len++;
      }
    }
  } while (len < limit);
  return sol;
}

export function getRandomScramble() {
  return getScramble("pyro");
}

regScrambler(["pyro", "pyrso", "pyrl4e", "pyrnb", "pyr4c"], getScramble);