position_id.ts

import crypto from 'crypto'

// WARNING: DO NOT CHANGE THESE WITH OPEN POSITIONS
const PREFIX = 'X'
const CHARSET = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZ'
const RANDOM_LENGTH = 16
const EXPRESSION = new RegExp(`^${PREFIX}-[0-9A-Z]{${RANDOM_LENGTH}}-\\d+$`)

// UNIQ-SEQ
export class PositionId {
  public uniq: string
  public seq: number

  constructor(public value: string) {
    if (!PositionId.match(value)) {
      throw 'value does not look like a PositionId'
    }

    let [prefix, rand, seq] = this.value.split('-')

    this.uniq = `${prefix}-${rand}`
    this.seq = parseInt(seq)
  }

  inc() {
    ++this.seq
    return this
  }

  eq(value: string) {
    return value.includes(this.uniq)
  }

  toString() {
    return `${this.uniq}-${this.seq}`
  }

  static match(value: string) {
    return value.match(EXPRESSION)
  }

  static gen() {
    return `${PREFIX}-${new Array(RANDOM_LENGTH)
      .fill(null)
      .map(() => CHARSET.charAt(crypto.randomInt(CHARSET.length)))
      .join('')}-0`
  }
}