class GachaMachine { items; tiers; maxTier; totalChance; pool; constructor(items){ this.items = []; this.tiers = []; this.pool = []; this.maxTier = 1; this.totalChance = 0; this.#configTiers(items); this.#configItems(items); } #configTiers(items) { let i = 0; const tiers = new Set(); while(i < items.length){ tiers.add(items[i].tier || 1); i += 1; } for (const tier of tiers){ if (tier > this.maxTier) this.maxTier = tier; } const itemsInTier = new Uint8Array(this.maxTier + 1); const totalChanceInTier = new Uint8Array(this.maxTier + 1); i = 0; while(i < items.length){ Atomics.add(itemsInTier, items[i].tier || 1, 1); Atomics.add(totalChanceInTier, items[i].tier || 1, items[i].chance); i += 1; } for (const tier1 of tiers){ this.tiers.push({ tier: tier1, totalChance: totalChanceInTier[tier1], items: itemsInTier[tier1] }); } this.pool = Array.from(tiers); } #configItems(items1) { let i1 = 0; let cumulativeChance = 0; while(i1 < items1.length){ cumulativeChance += items1[i1].chance; this.items.push({ result: items1[i1].result, chance: items1[i1].chance, cumulativeChance: cumulativeChance, tier: items1[i1].tier || 1 }); i1 += 1; } this.totalChance = cumulativeChance; } get(count = 1) { if (count === 1) { return [ GachaMachine.rollWithBinarySearch(this.items, this.totalChance), ]; } const result = new Array(count); let i = 0; while(i < count){ result[i] = GachaMachine.rollWithBinarySearch(this.items, this.totalChance); i += 1; } return result; } getUnique(count = 1) { if (count > this.items.length) { throw new RangeError(`Cannot pick ${count} unique items from a collection of ${this.items.length} items.`); } if (count === 1) { return [ GachaMachine.rollWithBinarySearch(this.items, this.totalChance), ]; } const tempItems = this.items.slice(0); const result = new Array(count); let i = 0; while(i < count){ const res = GachaMachine.#rollWithBinarySearchDetailed(tempItems, this.totalChance); result[i] = res.result; tempItems.splice(tempItems.findIndex((x)=>x.cumulativeChance === res.cumulativeChance), 1); i += 1; } return result; } getFromTier(tiers, count = 1) { const toRoll = []; let i = 0; let cumulativeChance = 0; while(i < this.items.length){ if (tiers.includes(this.items[i].tier)) { cumulativeChance += this.items[i].chance; toRoll.push({ ...this.items[i], cumulativeChance }); } i += 1; } if (toRoll.length === 0) return []; const result = []; i = 0; while(i < count){ result.push(GachaMachine.rollWithBinarySearch(toRoll, cumulativeChance)); i += 1; } return result; } static rollWithBinarySearch(items, totalChance) { return GachaMachine.#rollWithBinarySearchDetailed(items, totalChance).result; } static #rollWithBinarySearchDetailed(items2, totalChance) { if (!totalChance) totalChance = items2[items2.length - 1].cumulativeChance; if (items2.length === 1) return items2[0]; const rng = Math.random() * totalChance; let lower = 0; let max = items2.length - 1; let mid = Math.floor((max + lower) / 2); while(mid != 0 && lower <= max){ if (items2[mid].cumulativeChance > rng && items2[mid - 1].cumulativeChance < rng || items2[mid].cumulativeChance == rng) return items2[mid]; if (items2[mid].cumulativeChance < rng) { lower = mid + 1; mid = Math.floor((max + lower) / 2); } else { max = mid - 1; mid = Math.floor((max + lower) / 2); } } return items2[mid]; } static rollWithLinearSearch(choices, totalChance = 0) { let total = totalChance; let i = 0; if (totalChance === 0) { while(i < choices.length){ total += choices[i].chance; i += 1; } } const result = Math.random() * total; let going = 0.0; i = 0; while(i < choices.length){ going += choices[i].chance; if (result < going) { return choices[i].result; } i += 1; } return choices[Math.floor(Math.random() * choices.length)].result; }}export { GachaMachine as GachaMachine };