Never Stop Blowing Up

const clamp = (value, max, min = 0) =>
  Math.min(max, Math.max(min, value))

const sizes = ['d4', 'd6', 'd8', 'd10', 'd12', 'd20']

const rollDie = async (size) => {
  let total = 0
  let rolls = []
  let maxDie = size
  // do the roll
  const roll = await new Roll(size).roll()
  const result = parseInt(roll.total)
  total += result
  const max = roll.dice[0].faces
  const explodes = result === max
  rolls.push({roll, explodes})

  // post the result
  const content = explodes ? 'EXPLODES' : '--'

  // roll the next die, if explode
  if(explodes){
    const currentIndex = sizes.indexOf(size)
    const nextIndex = clamp(currentIndex + 1, (sizes.length-1))
    const explosion = await rollDie(sizes[nextIndex])
    total += explosion.total
    maxDie = explosion.maxDie
    rolls = [...rolls, ...explosion.rolls]
    // TODO: Update actor skill??
  }

  return { total, maxDie, rolls }
}

const {total, maxDie, rolls} = await rollDie('d4')

let enrichedRolls = ''
for(const roll of rolls) {
  enrichedRolls += await roll.roll.render()
  if(roll.explodes) enrichedRolls += '<h3>EXPLODES</h3>'
}

ChatMessage.create({
  user: game.user._id,
  speaker: ChatMessage.getSpeaker(),
  content: `<h1>RESULT: ${total}</h1><p>New die size: ${maxDie}</p>${enrichedRolls}`,
  sound: CONFIG.sounds.dice,
  rolls: rolls.map((r) => r.roll),
  type: CONST.CHAT_MESSAGE_TYPES.ROLL,
})

/* TODO:
  Add a listener to the chat message to spend TT; this should open a dialog and then trigger another explosion (or, rollDie call, with the next die size) on submit if the total for the rolls.
*/