Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 | import type { Piece, PieceType } from '../types' import { makeSquare, parseSquare } from '../types' /** * Path validation for Rithmomachia piece movement. * Checks if a move is geometrically legal and the path is clear. */ export interface PathValidationResult { valid: boolean reason?: string } /** * Check if a move is geometrically legal for a given piece type. * Does NOT check if the path is clear (that's done separately). */ export function isGeometryLegal( pieceType: PieceType, from: string, to: string ): PathValidationResult { if (from === to) { return { valid: false, reason: 'Cannot move to the same square' } } const fromCoords = parseSquare(from) const toCoords = parseSquare(to) const deltaFile = toCoords.file - fromCoords.file const deltaRank = toCoords.rank - fromCoords.rank const absDeltaFile = Math.abs(deltaFile) const absDeltaRank = Math.abs(deltaRank) switch (pieceType) { case 'C': { // Circle: diagonal only (like bishop) if (absDeltaFile === absDeltaRank && absDeltaFile > 0) { return { valid: true } } return { valid: false, reason: 'Circles move diagonally' } } case 'T': { // Triangle: orthogonal only (like rook) if ((deltaFile === 0 && deltaRank !== 0) || (deltaRank === 0 && deltaFile !== 0)) { return { valid: true } } return { valid: false, reason: 'Triangles move orthogonally' } } case 'S': { // Square: queen-like (orthogonal or diagonal) const isDiagonal = absDeltaFile === absDeltaRank && absDeltaFile > 0 const isOrthogonal = (deltaFile === 0 && deltaRank !== 0) || (deltaRank === 0 && deltaFile !== 0) if (isDiagonal || isOrthogonal) { return { valid: true } } return { valid: false, reason: 'Squares move orthogonally or diagonally', } } case 'P': { // Pyramid: king-like (1 step in any direction) if (absDeltaFile <= 1 && absDeltaRank <= 1 && (absDeltaFile > 0 || absDeltaRank > 0)) { return { valid: true } } return { valid: false, reason: 'Pyramids move 1 step in any direction' } } default: return { valid: false, reason: 'Unknown piece type' } } } /** * Check if the path from 'from' to 'to' is clear (no pieces in between). * Assumes the geometry is already validated. */ export function isPathClear( pieces: Record<string, Piece>, from: string, to: string ): PathValidationResult { const fromCoords = parseSquare(from) const toCoords = parseSquare(to) const deltaFile = toCoords.file - fromCoords.file const deltaRank = toCoords.rank - fromCoords.rank // Calculate step direction const stepFile = deltaFile === 0 ? 0 : deltaFile > 0 ? 1 : -1 const stepRank = deltaRank === 0 ? 0 : deltaRank > 0 ? 1 : -1 // Calculate number of steps (excluding start and end) const steps = Math.max(Math.abs(deltaFile), Math.abs(deltaRank)) - 1 // Check each intermediate square let currentFile = fromCoords.file + stepFile let currentRank = fromCoords.rank + stepRank for (let i = 0; i < steps; i++) { const square = makeSquare(currentFile, currentRank) const pieceAtSquare = Object.values(pieces).find((p) => p.square === square && !p.captured) if (pieceAtSquare) { return { valid: false, reason: `Path blocked by ${pieceAtSquare.id} at ${square}`, } } currentFile += stepFile currentRank += stepRank } return { valid: true } } /** * Validate a complete move (geometry + path clearance). */ export function validateMove( piece: Piece, from: string, to: string, pieces: Record<string, Piece> ): PathValidationResult { // Check geometry const geometryCheck = isGeometryLegal(piece.type, from, to) if (!geometryCheck.valid) { return geometryCheck } // Check path clearance const pathCheck = isPathClear(pieces, from, to) if (!pathCheck.valid) { return pathCheck } return { valid: true } } /** * Get all legal move destinations for a piece (ignoring captures/relations). * Returns an array of square notations. */ export function getLegalMoves(piece: Piece, pieces: Record<string, Piece>): string[] { const legalMoves: string[] = [] // Generate all possible squares on the board for (let file = 0; file < 16; file++) { for (let rank = 1; rank <= 8; rank++) { const targetSquare = makeSquare(file, rank) // Skip if same square if (targetSquare === piece.square) continue // Check if move is legal const validation = validateMove(piece, piece.square, targetSquare, pieces) if (validation.valid) { legalMoves.push(targetSquare) } } } return legalMoves } /** * Check if a square is within board bounds. */ export function isSquareValid(square: string): boolean { if (square.length !== 2) return false const file = square.charCodeAt(0) - 65 // A=0, B=1, ..., P=15 const rank = Number.parseInt(square[1], 10) return file >= 0 && file <= 15 && rank >= 1 && rank <= 8 } /** * Get the direction of movement (for UI purposes). */ export function getDirection( from: string, to: string ): { horizontal: 'left' | 'right' | 'none' vertical: 'up' | 'down' | 'none' } { const fromCoords = parseSquare(from) const toCoords = parseSquare(to) const deltaFile = toCoords.file - fromCoords.file const deltaRank = toCoords.rank - fromCoords.rank return { horizontal: deltaFile < 0 ? 'left' : deltaFile > 0 ? 'right' : 'none', vertical: deltaRank < 0 ? 'down' : deltaRank > 0 ? 'up' : 'none', } } |