ChatRPG

/** * Dice Engine - Core Dice Rolling Logic * Supports: NdX+Y, NdXkh/kl/dh/dl modifiers */ import { createBox, renderDiceHorizontal, centerText, BOX, D20_SPECIAL } from './ascii-art.js'; // Dice roll result export interface DiceResult { expression: string; rolls: number[]; kept: number[]; modifier: number; total: number; } // Parse dice expression const DICE_REGEX = /^(\d+)d(\d+)(kh\d+|kl\d+|dh\d+|dl\d+)?([+-]\d+)?$/i; export function parseDice(expression: string): DiceResult { const cleaned = expression.replace(/\s/g, '').toLowerCase(); const match = cleaned.match(DICE_REGEX); if (!match) { throw new Error(`Invalid dice expression: "${expression}"`); } const numDice = parseInt(match[1]); const dieSize = parseInt(match[2]); const keepDrop = match[3] || ''; const modifierStr = match[4] || ''; if (numDice < 1 || numDice > 100) { throw new Error(`Invalid number of dice: ${numDice}`); } if (dieSize < 2 || dieSize > 1000) { throw new Error(`Invalid die size: ${dieSize}`); } // Roll dice const rolls: number[] = []; for (let i = 0; i < numDice; i++) { rolls.push(Math.floor(Math.random() * dieSize) + 1); } // Apply keep/drop modifier let kept = [...rolls]; if (keepDrop) { const type = keepDrop.slice(0, 2); const count = parseInt(keepDrop.slice(2)); if (count > rolls.length) { throw new Error(`Cannot keep/drop ${count} from ${rolls.length} dice`); } const sorted = [...rolls].sort((a, b) => b - a); // Descending switch (type) { case 'kh': // Keep highest kept = sorted.slice(0, count); break; case 'kl': // Keep lowest kept = sorted.slice(-count); break; case 'dh': // Drop highest kept = sorted.slice(count); break; case 'dl': // Drop lowest kept = sorted.slice(0, -count); break; } } // Parse modifier const modifier = modifierStr ? parseInt(modifierStr) : 0; // Calculate total const total = kept.reduce((sum, n) => sum + n, 0) + modifier; return { expression, rolls, kept, modifier, total, }; } // Format dice result as ASCII art export function formatDiceResult(result: DiceResult, reason?: string): string { const content: string[] = []; const box = BOX.LIGHT; // Title line content.push(`DICE ROLL: ${result.expression}`); if (reason) { content.push(`(${reason})`); } content.push(''); // For d20 critical hits/fails, show special display if (result.expression.toLowerCase().includes('d20') && result.rolls.length === 1) { const roll = result.rolls[0]; if (roll === 1 || roll === 20) { const special = D20_SPECIAL[roll]; special.forEach(line => content.push(line)); content.push(''); content.push(`TOTAL: ${result.total}`); return createBox('DICE ROLL', content, undefined, 'HEAVY'); } } // Show dice faces (for reasonable number of dice) if (result.rolls.length <= 6 && result.rolls.every(r => r <= 6)) { const diceFaces = renderDiceHorizontal(result.rolls); diceFaces.forEach(line => content.push(line)); content.push(''); // Show which were kept if different if (result.rolls.length !== result.kept.length) { const keptIndices = result.rolls.map((r, i) => result.kept.includes(r) && !result.kept.slice(0, result.kept.indexOf(r)).includes(r) ? i : -1 ).filter(i => i >= 0); content.push(`KEPT: [${result.kept.join(', ')}]`); content.push(`DROPPED: [${result.rolls.filter(r => !result.kept.includes(r)).join(', ')}]`); content.push(''); } } else { // For many dice or large dice, show numbers if (result.rolls.length !== result.kept.length) { content.push(`ROLLED: [${result.rolls.join(', ')}]`); content.push(`KEPT: [${result.kept.join(', ')}]`); } else { content.push(`ROLLED: [${result.rolls.join(', ')}]`); } content.push(''); } // Show calculation const diceSum = result.kept.reduce((sum, n) => sum + n, 0); if (result.modifier !== 0) { const sign = result.modifier > 0 ? '+' : ''; content.push(`CALCULATION: ${diceSum} ${sign}${result.modifier} = ${result.total}`); } else { content.push(`TOTAL: ${result.total}`); } // Add bottom divider content.push(''); content.push('─'.repeat(40)); // Will be adjusted by auto-sizing content.push(`FINAL RESULT: ${result.total}`); return createBox('DICE ROLL', content, undefined, 'HEAVY'); }