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| 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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 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HarmonyDeclaration['params'] reason?: string } export type HarmonyLayoutMode = 'adjacent' | 'equalSpacing' | 'collinear' /** * Check if three squares are collinear (on same row, column, or diagonal) */ function areCollinear(sq1: string, sq2: string, sq3: string): boolean { const p1 = parseSquare(sq1) const p2 = parseSquare(sq2) const p3 = parseSquare(sq3) if (!p1 || !p2 || !p3) return false // Same rank (horizontal row) if (p1.rank === p2.rank && p2.rank === p3.rank) return true // Same file (vertical column) if (p1.file === p2.file && p2.file === p3.file) return true // Diagonal: check if slope is consistent const dx12 = p2.file - p1.file const dy12 = p2.rank - p1.rank const dx23 = p3.file - p2.file const dy23 = p3.rank - p2.rank // Cross product should be zero for collinear points return dx12 * dy23 === dy12 * dx23 } /** * Get the distance between two squares (Manhattan or diagonal) */ function getDistance(sq1: string, sq2: string): number { const p1 = parseSquare(sq1) const p2 = parseSquare(sq2) if (!p1 || !p2) return Infinity return Math.max(Math.abs(p2.file - p1.file), Math.abs(p2.rank - p1.rank)) } /** * Determine which piece is spatially in the middle on a line * Returns the middle piece, or null if they're not properly ordered */ function findMiddlePiece(pieces: Piece[]): Piece | null { if (pieces.length !== 3) return null const [p1, p2, p3] = pieces // Check all permutations to find which one is in the middle const positions = [parseSquare(p1.square), parseSquare(p2.square), parseSquare(p3.square)] if (!positions[0] || !positions[1] || !positions[2]) return null // For each piece, check if it's between the other two for (let i = 0; i < 3; i++) { const candidate = positions[i] const others = [positions[(i + 1) % 3], positions[(i + 2) % 3]] // Check if candidate is between the other two on all axes const betweenX = (candidate.file >= others[0].file && candidate.file <= others[1].file) || (candidate.file >= others[1].file && candidate.file <= others[0].file) const betweenY = (candidate.rank >= others[0].rank && candidate.rank <= others[1].rank) || (candidate.rank >= others[1].rank && candidate.rank <= others[0].rank) if (betweenX && betweenY) { return pieces[i] } } return null } /** * Check if three pieces satisfy layout constraint */ function checkLayout(pieces: Piece[], mode: HarmonyLayoutMode): boolean { if (pieces.length !== 3) return false const [p1, p2, p3] = pieces const squares = [p1.square, p2.square, p3.square] // All modes require collinearity if (!areCollinear(squares[0], squares[1], squares[2])) { return false } // Find which piece is in the middle const middle = findMiddlePiece(pieces) if (!middle) return false const others = pieces.filter((p) => p !== middle) if (mode === 'adjacent') { // All distances must be 1 const d1 = getDistance(middle.square, others[0].square) const d2 = getDistance(middle.square, others[1].square) return d1 === 1 && d2 === 1 } if (mode === 'equalSpacing') { // Distances must be equal (and can be 1 or 2) const d1 = getDistance(middle.square, others[0].square) const d2 = getDistance(middle.square, others[1].square) return d1 === d2 && (d1 === 1 || d1 === 2) } // mode === 'collinear': any spacing is OK (already checked collinearity) return true } /** * Check if three values form an arithmetic proportion (A-M-B). * AP: 2M = A + B (middle is arithmetic mean) */ function isArithmeticProportion(a: number, m: number, b: number): HarmonyValidationResult { if (2 * m === a + b) { return { valid: true, type: 'ARITH', params: { a: a.toString(), m: m.toString(), b: b.toString(), }, } } return { valid: false, reason: `Not arithmetic: 2·${m} ≠ ${a} + ${b} (${2 * m} ≠ ${a + b})`, } } /** * Check if three values form a geometric proportion (A-M-B). * GP: M² = A · B (middle is geometric mean) */ function isGeometricProportion(a: number, m: number, b: number): HarmonyValidationResult { if (m * m === a * b) { return { valid: true, type: 'GEOM', params: { a: a.toString(), m: m.toString(), b: b.toString(), }, } } return { valid: false, reason: `Not geometric: ${m}² ≠ ${a} · ${b} (${m * m} ≠ ${a * b})`, } } /** * Check if three values form a harmonic proportion (A-M-B). * HP: 2AB = M(A + B) (middle is harmonic mean) * Equivalently: 1/A, 1/M, 1/B forms an arithmetic progression */ function isHarmonicProportion(a: number, m: number, b: number): HarmonyValidationResult { if (a === 0 || b === 0 || m === 0) { return { valid: false, reason: 'Harmonic proportion cannot contain 0', } } if (2 * a * b === m * (a + b)) { return { valid: true, type: 'HARM', params: { a: a.toString(), m: m.toString(), b: b.toString(), }, } } return { valid: false, reason: `Not harmonic: 2·${a}·${b} ≠ ${m}·(${a}+${b}) (${2 * a * b} ≠ ${m * (a + b)})`, } } /** * Validate if three pieces form a valid harmony. * Returns the first valid proportion type found, or invalid result. */ export function validateHarmony( pieces: Piece[], color: Color, layoutMode: HarmonyLayoutMode = 'adjacent' ): HarmonyValidationResult { // Check: exactly 3 pieces if (pieces.length !== 3) { return { valid: false, reason: 'Harmony requires exactly 3 pieces' } } // Check: all pieces must be in enemy half const notInEnemyHalf = pieces.filter((p) => !isInEnemyHalf(p.square, color)) if (notInEnemyHalf.length > 0) { return { valid: false, reason: `Pieces not in enemy half: ${notInEnemyHalf.map((p) => p.square).join(', ')}`, } } // Check: must satisfy layout constraint if (!checkLayout(pieces, layoutMode)) { return { valid: false, reason: `Pieces not in valid ${layoutMode} layout (must be collinear with correct spacing)`, } } // Find middle piece const middle = findMiddlePiece(pieces) if (!middle) { return { valid: false, reason: 'Could not determine middle piece' } } const others = pieces.filter((p) => p !== middle) // Extract values (handling Pyramids) const getVal = (p: Piece) => { const val = getEffectiveValue(p) if (val === null) { throw new Error(`Piece ${p.id} has no effective value (Pyramid face not set?)`) } return val } try { const m = getVal(middle) const a = getVal(others[0]) const b = getVal(others[1]) // Check for duplicates if (a === m || m === b || a === b) { return { valid: false, reason: 'Harmony cannot contain duplicate values', } } // Try all three proportion types const apCheck = isArithmeticProportion(a, m, b) if (apCheck.valid) return apCheck const gpCheck = isGeometricProportion(a, m, b) if (gpCheck.valid) return gpCheck const hpCheck = isHarmonicProportion(a, m, b) if (hpCheck.valid) return hpCheck return { valid: false, reason: 'Values do not form any valid proportion' } } catch (err) { return { valid: false, reason: (err as Error).message } } } /** * Find all possible harmonies for a color from a set of pieces. * Returns an array of all valid 3-piece combinations that form harmonies. */ export function findPossibleHarmonies( pieces: Record<string, Piece>, color: Color, layoutMode: HarmonyLayoutMode = 'adjacent' ): Array<{ pieceIds: string[]; validation: HarmonyValidationResult }> { const results: Array<{ pieceIds: string[] validation: HarmonyValidationResult }> = [] // Get all live pieces for this color in enemy half const candidatePieces = Object.values(pieces).filter( (p) => p.color === color && !p.captured && isInEnemyHalf(p.square, color) ) if (candidatePieces.length < 3) { return results } // Generate all combinations of exactly 3 pieces for (let i = 0; i < candidatePieces.length; i++) { for (let j = i + 1; j < candidatePieces.length; j++) { for (let k = j + 1; k < candidatePieces.length; k++) { const combo = [candidatePieces[i], candidatePieces[j], candidatePieces[k]] const validation = validateHarmony(combo, color, layoutMode) if (validation.valid) { results.push({ pieceIds: combo.map((p) => p.id), validation, }) } } } } return results } /** * Check if a specific harmony declaration is currently valid. * Used for harmony persistence checking. */ export function isHarmonyStillValid( pieces: Record<string, Piece>, harmony: HarmonyDeclaration, layoutMode: HarmonyLayoutMode = 'adjacent' ): boolean { const relevantPieces = harmony.pieceIds.map((id) => pieces[id]).filter((p) => p && !p.captured) if (relevantPieces.length !== 3) { return false } const validation = validateHarmony(relevantPieces, harmony.by, layoutMode) return validation.valid } /** * Check if ANY valid harmony exists for a color (for harmony persistence recheck). */ export function hasAnyValidHarmony( pieces: Record<string, Piece>, color: Color, layoutMode: HarmonyLayoutMode = 'adjacent' ): boolean { const harmonies = findPossibleHarmonies(pieces, color, layoutMode) return harmonies.length > 0 } |