| 1 | import { ChessRules } from "@/base_rules"; |
| 2 | |
| 3 | export class ShatranjRules extends ChessRules { |
| 4 | static get HasFlags() { |
| 5 | return false; |
| 6 | } |
| 7 | |
| 8 | static get HasEnpassant() { |
| 9 | return false; |
| 10 | } |
| 11 | |
| 12 | static get PawnSpecs() { |
| 13 | return Object.assign( |
| 14 | {}, |
| 15 | ChessRules.PawnSpecs, |
| 16 | { |
| 17 | twoSquares: false, |
| 18 | promotions: [V.QUEEN] |
| 19 | } |
| 20 | ); |
| 21 | } |
| 22 | |
| 23 | static get ElephantSteps() { |
| 24 | return [ |
| 25 | [-2, -2], |
| 26 | [-2, 2], |
| 27 | [2, -2], |
| 28 | [2, 2] |
| 29 | ]; |
| 30 | } |
| 31 | |
| 32 | static GenRandInitFen(randomness) { |
| 33 | // Remove castle flags and en-passant indication |
| 34 | return ChessRules.GenRandInitFen(randomness).slice(0, -7); |
| 35 | } |
| 36 | |
| 37 | getPotentialBishopMoves(sq) { |
| 38 | let moves = this.getSlideNJumpMoves(sq, V.ElephantSteps, "oneStep"); |
| 39 | // Complete with "repositioning moves": like a queen, without capture |
| 40 | let repositioningMoves = this.getSlideNJumpMoves( |
| 41 | sq, |
| 42 | V.steps[V.BISHOP], |
| 43 | "oneStep" |
| 44 | ).filter(m => m.vanish.length == 1); |
| 45 | return moves.concat(repositioningMoves); |
| 46 | } |
| 47 | |
| 48 | getPotentialQueenMoves(sq) { |
| 49 | // Diagonal capturing moves |
| 50 | let captures = this.getSlideNJumpMoves( |
| 51 | sq, |
| 52 | V.steps[V.BISHOP], |
| 53 | "oneStep" |
| 54 | ).filter(m => m.vanish.length == 2); |
| 55 | return captures.concat( |
| 56 | // Orthogonal non-capturing moves |
| 57 | this.getSlideNJumpMoves( |
| 58 | sq, |
| 59 | V.steps[V.ROOK], |
| 60 | "oneStep" |
| 61 | ).filter(m => m.vanish.length == 1) |
| 62 | ); |
| 63 | } |
| 64 | |
| 65 | isAttackedByBishop(sq, color) { |
| 66 | return this.isAttackedBySlideNJump( |
| 67 | sq, |
| 68 | color, |
| 69 | V.BISHOP, |
| 70 | V.ElephantSteps, |
| 71 | "oneStep" |
| 72 | ); |
| 73 | } |
| 74 | |
| 75 | isAttackedByQueen(sq, color) { |
| 76 | return this.isAttackedBySlideNJump( |
| 77 | sq, |
| 78 | color, |
| 79 | V.QUEEN, |
| 80 | V.steps[V.BISHOP], |
| 81 | "oneStep" |
| 82 | ); |
| 83 | } |
| 84 | |
| 85 | getCurrentScore() { |
| 86 | const color = this.turn; |
| 87 | const getScoreLost = () => { |
| 88 | // Result if I lose: |
| 89 | return color == "w" ? "0-1" : "1-0"; |
| 90 | }; |
| 91 | if (!this.atLeastOneMove()) |
| 92 | // No valid move: I lose (this includes checkmate) |
| 93 | return getScoreLost(); |
| 94 | // Win if the opponent has no pieces left (except king), |
| 95 | // and cannot bare king on the next move. |
| 96 | let piecesLeft = { |
| 97 | // No need to remember all pieces' squares: |
| 98 | // variable only used if just one remaining piece. |
| 99 | "w": {count: 0, square: null}, |
| 100 | "b": {count: 0, square: null} |
| 101 | }; |
| 102 | outerLoop: for (let i=0; i<V.size.x; i++) { |
| 103 | for (let j=0; j<V.size.y; j++) { |
| 104 | if (this.board[i][j] != V.EMPTY && this.getPiece(i,j) != V.KING) { |
| 105 | const sqCol = this.getColor(i,j); |
| 106 | piecesLeft[sqCol].count++; |
| 107 | piecesLeft[sqCol].square = [i,j]; |
| 108 | } |
| 109 | } |
| 110 | } |
| 111 | if (Object.values(piecesLeft).every(v => v.count > 0)) |
| 112 | return "*"; |
| 113 | // No pieces left for some side: if both kings are bare, it's a draw |
| 114 | if (Object.values(piecesLeft).every(v => v.count == 0)) |
| 115 | return "1/2"; |
| 116 | if (piecesLeft[color].count > 0) |
| 117 | // He could have drawn, but didn't take my last piece... |
| 118 | return color == "w" ? "1-0" : "0-1"; |
| 119 | const oppCol = V.GetOppCol(color); |
| 120 | if (piecesLeft[oppCol].count >= 2) |
| 121 | // 2 enemy units or more: I lose |
| 122 | return getScoreLost(); |
| 123 | // I don't have any piece, my opponent have one: can I take it? |
| 124 | if (this.isAttacked(piecesLeft[oppCol].square, color)) |
| 125 | // Yes! But I still need to take it |
| 126 | return "*"; |
| 127 | // No :( |
| 128 | return getScoreLost(); |
| 129 | } |
| 130 | |
| 131 | static get VALUES() { |
| 132 | return { |
| 133 | p: 1, |
| 134 | r: 5, |
| 135 | n: 3, |
| 136 | b: 3, |
| 137 | q: 3, |
| 138 | k: 1000 |
| 139 | }; |
| 140 | } |
| 141 | }; |