/**
 * Булстат е идентификатор, какъвто има всяка фирма в България. Булстатът може
 * да бъде 9, 10 или 13 знака.
 */

const CONTROLS_9_1: readonly number[] = [1, 2, 3, 4, 5, 6, 7, 8];
const CONTROLS_9_2: readonly number[] = [3, 4, 5, 6, 7, 8, 9, 10];
const CONTROLS_13_1: readonly number[] = [2, 7, 3, 5];
const CONTROLS_13_2: readonly number[] = [4, 9, 5, 7];

class Bulstat {
  private _value: string;

  constructor(value: string) {
    if (typeof value !== "string") {
      throw new Error(`${value} is not of type string!`);
    }

    if (value.length > 2 && value.substr(0, 2) == "BG") {
      value = value.substring(2);
    }

    if (value.length !== 9 && value.length !== 13) {
      throw new Error(`${value} is not of size 9 or 13!`);
    }

    this._value = value;
  }

  get value(): string {
    return this._value;
  }

  get isValid(): boolean {
    const val: number[] = [];

    for (let i = 0; i < this._value.length; i++) {
      val[i] = ~~this._value.charAt(i);
    }

    let sum = 0;
    for (let i = 0; i < 8; i++) {
      sum += val[i] * CONTROLS_9_1[i];
    }

    let mod = sum % 11;
    if (mod > 9) {
      sum = 0;
      for (let i = 0; i < 8; i++) {
        sum += val[i] * CONTROLS_9_2[i];
      }

      mod = sum % 11;
      mod = mod > 9 ? 0 : mod;
    }

    if (this._value.length === 9) {
      return mod === val[8];
    }

    // set control for 9-digit BULSTAT
    val[8] = mod;

    sum = 0;
    for (let i = 8; i < 12; i++) {
      sum += val[i] * CONTROLS_13_1[i - 8];
    }

    mod = sum % 11;
    if (mod > 9) {
      sum = 0;
      for (let i = 8; i < 12; i++) {
        sum += val[i] * CONTROLS_13_2[i - 8];
      }

      mod = sum % 11;
      mod = mod > 9 ? 0 : mod;
    }

    return mod === val[12];
  }
}

export default Bulstat;