import { Action } from './action.js';
import { Actor } from './actor.js';
import { CryptoUtil } from './crypto.js';

class Worker {
  constructor(reputationPublicKey, tokenId, stakeAmount, duration) {
    this.reputationPublicKey = reputationPublicKey;
    this.tokenId = tokenId;
    this.stakeAmount = stakeAmount;
    this.duration = duration;
    this.available = true;
    this.assignedRequestId = null;
  }
}

/**
 * Purpose: Enable staking reputation to enter the pool of workers
 */
export class Availability extends Actor {
  constructor(dao, name) {
    super(name);
    this.dao = dao;

    this.actions = {
      assignWork: new Action('assign work'),
    };

    this.workers = new Map();
  }

  register(reputationPublicKey, { stakeAmount, tokenId, duration }) {
    // TODO: Should be signed by token owner
    this.dao.reputation.lock(tokenId, stakeAmount, duration);
    const workerId = CryptoUtil.randomUUID();
    this.workers.set(workerId, new Worker(reputationPublicKey, tokenId, stakeAmount, duration));
    return workerId;
  }

  get availableWorkers() {
    return Array.from(this.workers.values()).filter(({ available }) => !!available);
  }

  async assignWork(requestId) {
    const totalAmountStaked = this.availableWorkers
      .reduce((total, { stakeAmount }) => total += stakeAmount, 0);
    // Imagine all these amounts layed end-to-end along a number line.
    // To weight choice by amount staked, pick a stake by choosing a number at random
    // from within that line segment.
    const randomChoice = Math.random() * totalAmountStaked;
    let index = 0;
    let acc = 0;
    for (const { stakeAmount } of this.workers.values()) {
      acc += stakeAmount;
      if (acc >= randomChoice) {
        break;
      }
      index += 1;
    }
    const worker = this.availableWorkers[index];
    worker.available = false;
    worker.assignedRequestId = requestId;

    // TODO: Notify assignee
    return worker;
  }

  async getAssignedWork(workerId) {
    const worker = this.workers.get(workerId);
    return worker.assignedRequestId;
  }
}