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export interface GachaData<ItemType> {  result: ItemType;  chance: number;  tier?: number;}
export interface GachaChoice<ItemType> {  result: ItemType;  chance: number;}
export interface ComputedGachaData<ItemType> {  result: ItemType;  cumulativeChance: number;  cumulativeChanceInTier: number;  tier: number;}
export interface ComputedTierData {  totalChance: number;  items: number;  tier: number;}
export class GachaMachine<ItemType> {  items: ComputedGachaData<ItemType>[];  tiers: ComputedTierData[];  maxTier: number;  totalChance: number;  pool: number[];  constructor(items: GachaData<ItemType>[]) {    this.items = [];    this.tiers = [];    this.pool = [];    this.maxTier = 1;    this.totalChance = 0;    this.#configTiers(items);    this.#configItems(items);  }  #configTiers(items: GachaData<ItemType>[]) {    let i = 0;    const tiers = new Set<number>();    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 tier of tiers) {      this.tiers.push({        tier: tier,        totalChance: totalChanceInTier[tier],        items: itemsInTier[tier],      });    }    this.pool = Array.from(tiers);  }  #configItems(items: GachaData<ItemType>[]) {    let i = 0;    let cumulativeChance = 0;    const cumulativeChanceInTier = new Uint8Array(this.maxTier + 1);    while (i < items.length) {      this.items.push({        result: items[i].result,        cumulativeChance: cumulativeChance,        cumulativeChanceInTier: Atomics.add(          cumulativeChanceInTier,          items[i].tier || 1,          items[i].chance,        ),        tier: items[i].tier || 1,      });      cumulativeChance += items[i].chance;      i += 1;    }    this.totalChance = cumulativeChance;  }  get(count = 1): ItemType[] {    const result = [];    let i = 0;    while (i < count) {      result.push(this.#roll());      i += 1;    }    return result;  }  #roll(): ItemType {    if (this.items.length === 1) return this.items[0].result;    const rng = Math.random() * this.totalChance;    let lower = 0;    let max = this.items.length - 1;    let mid = Math.floor((max + lower) / 2);    while (      !(this.items[mid].cumulativeChance > rng &&        this.items[mid - 1].cumulativeChance < rng) &&      this.items[mid].cumulativeChance !== rng && mid != 0 && lower <= max    ) {      //        console.log(this.items[mid].cumulativeChance, this.items[mid-1].cumulativeChance, rng)      //        console.log(rng, mid)      if (this.items[mid].cumulativeChance < rng) {        //        console.log("le", max, lower, mid)        //        if(mid === 150) throw new Error("!%)")        lower = mid + 1;        mid = Math.floor((max + lower) / 2);      } else {        //        console.log("mo", max, lower, mid)
        max = mid - 1;        mid = Math.floor((max + lower) / 2);      }    }    return this.items[mid].result;  }}