mythic-oracle/public/js/dice.js

// Mythic Oracle — Dice: pool builder, custom roll, percentile, ability score
// Pure frontend — no backend calls.

const dicePool = { 4: 0, 6: 0, 8: 0, 10: 0, 12: 0, 20: 0, 2: 0 };
const POOL_MAX = 25;
const DIE_ORDER = [4, 6, 8, 10, 12, 20, 2];

function addDie(sides) {
  const total = DIE_ORDER.reduce((s, d) => s + dicePool[d], 0);
  if (total >= POOL_MAX) return;
  dicePool[sides]++;
  updatePoolDisplay();
}

function clearPool() {
  DIE_ORDER.forEach((d) => {
    dicePool[d] = 0;
  });
  updatePoolDisplay();
  const box = document.getElementById('poolResult');
  box.className = 'dice-result-box';
  box.innerHTML = '<span class="placeholder">Build a pool and roll.</span>';
}

function updatePoolDisplay() {
  const total = DIE_ORDER.reduce((s, d) => s + dicePool[d], 0);
  const display = document.getElementById('poolDisplay');
  const capMsg = document.getElementById('poolCapMsg');

  const parts = DIE_ORDER.filter((d) => dicePool[d] > 0).map((d) => `${dicePool[d]}d${d}`);
  if (parts.length === 0) {
    display.innerHTML = '<span class="placeholder">No dice in pool — click above to add.</span>';
  } else {
    display.textContent = parts.join(' + ');
  }

  const capped = total >= POOL_MAX;
  capMsg.style.display = capped ? '' : 'none';
  document.querySelectorAll('#diceGrid .die-btn').forEach((btn) => {
    btn.disabled = capped;
  });
}

function rollPool() {
  const total = DIE_ORDER.reduce((s, d) => s + dicePool[d], 0);
  const box = document.getElementById('poolResult');
  if (total === 0) {
    box.className = 'dice-result-box animate';
    box.innerHTML = '<span class="placeholder">Add dice to the pool first.</span>';
    void box.offsetWidth;
    return;
  }

  const results = {};
  let grandTotal = 0;
  DIE_ORDER.forEach((sides) => {
    if (dicePool[sides] > 0) {
      results[sides] = [];
      for (let i = 0; i < dicePool[sides]; i++) {
        const roll = Math.floor(Math.random() * sides) + 1;
        results[sides].push(roll);
        grandTotal += roll;
      }
    }
  });

  const activeDice = DIE_ORDER.filter((s) => results[s]);

  const groupedHTML = activeDice
    .map((sides) => {
      const rolls = results[sides];
      const sum = rolls.reduce((a, b) => a + b, 0);
      const rollStr = rolls.length > 1 ? `${rolls.join(' + ')} = ${sum}` : `${sum}`;
      return `<div class="pool-result-group"><span class="pool-group-type">d${sides}</span>: ${rollStr}</div>`;
    })
    .join('');

  box.className = 'dice-result-box animate';
  box.innerHTML = `
    <div class="dice-total">${grandTotal}</div>
    <div class="dice-divider"></div>
    <div class="pool-result-groups">${groupedHTML}</div>
  `;
  void box.offsetWidth;
}

function validateCustomRoll() {
  const qty = document.getElementById('customQty').value;
  const sides = document.getElementById('customSides').value;
  const btn = document.getElementById('customRollBtn');

  const isPosInt = (v) => v !== '' && Number.isInteger(Number(v)) && Number(v) > 0;
  const valid = isPosInt(qty) && Number(qty) <= 25 && isPosInt(sides);

  btn.disabled = !valid;
}

function rollCustom() {
  const qty = Number(document.getElementById('customQty').value);
  const sides = Number(document.getElementById('customSides').value);
  const box = document.getElementById('customResult');

  const rolls = [];
  let total = 0;
  for (let i = 0; i < qty; i++) {
    const roll = Math.floor(Math.random() * sides) + 1;
    rolls.push(roll);
    total += roll;
  }

  box.className = 'dice-result-box animate';
  box.innerHTML = `
    <div class="dice-total">${total}</div>
    <div class="dice-breakdown">${qty}d${sides} &nbsp;[${rolls.join(', ')}]</div>
  `;
  void box.offsetWidth;
}

function clearCustomRoll() {
  const box = document.getElementById('customResult');
  box.className = 'dice-result-box';
  box.innerHTML = '<span class="placeholder">Enter a quantity and die size.</span>';
}

function quickRoll(sides, qty, mod, label, boxId) {
  const rolls = [];
  for (let i = 0; i < qty; i++) {
    rolls.push(Math.floor(Math.random() * sides) + 1);
  }
  let total = rolls.reduce((a, b) => a + b, 0) + mod;
  if (label.includes('drop lowest')) {
    const sorted = [...rolls].sort((a, b) => a - b);
    sorted.shift();
    total = sorted.reduce((a, b) => a + b, 0);
  }
  const box = document.getElementById(boxId);
  box.classList.add('animate');
  box.innerHTML = `
    <div class="dice-total">${total}</div>
    <div class="dice-breakdown">${label} &nbsp;[${rolls.join(', ')}]</div>
  `;
  void box.offsetWidth;
}

function rollAbilityArray() {
  const lines = [];
  for (let i = 0; i < 6; i++) {
    const rolls = [];
    for (let j = 0; j < 4; j++) {
      rolls.push(Math.floor(Math.random() * 6) + 1);
    }
    const sorted = [...rolls].sort((a, b) => a - b);
    sorted.shift();
    const total = sorted.reduce((a, b) => a + b, 0);
    lines.push(`${rolls.join(', ')} &nbsp;→&nbsp; ${total}`);
  }
  const box = document.getElementById('abilityResult');
  box.className = 'dice-result-box animate';
  box.innerHTML = `<div class="dice-breakdown">${lines.join('<br>')}</div>`;
  void box.offsetWidth;
}

function init() {
  document.querySelectorAll('#diceGrid .die-btn').forEach((btn) => {
    btn.addEventListener('click', () => addDie(Number(btn.dataset.sides)));
  });

  document.getElementById('poolRollBtn').addEventListener('click', rollPool);
  document.getElementById('poolClearBtn').addEventListener('click', clearPool);

  document.getElementById('customQty').addEventListener('input', validateCustomRoll);
  document.getElementById('customSides').addEventListener('input', validateCustomRoll);
  document.getElementById('customRollBtn').addEventListener('click', rollCustom);
  document.getElementById('customClearBtn').addEventListener('click', clearCustomRoll);

  document.getElementById('percentileTensBtn').addEventListener('click', () => {
    quickRoll(10, 1, 0, 'Percentile (tens)', 'percentileResult');
  });
  document.getElementById('percentileOnesBtn').addEventListener('click', () => {
    quickRoll(10, 1, 0, 'Percentile (ones)', 'percentileResult');
  });

  document.getElementById('ability4d6Btn').addEventListener('click', () => {
    quickRoll(6, 4, -4, '4d6 drop lowest (approx)', 'abilityResult');
  });
  document.getElementById('abilityArrayBtn').addEventListener('click', rollAbilityArray);
}

document.addEventListener('DOMContentLoaded', init);