numbers/src/ordered-numbers.class.ts

export class OrderedNumbers {
  constructor(private numbers: number[] = [], private readonly unique = true) {
    if (!this.isValid) {
      this.sort();
      if (this.unique) {
        this.makeUnique();
      }
    }
  }

  private get isValid(): boolean {
    for (const [index, number] of this.numbers.entries()) {
      if (index > 0 && number < this.numbers[index - 1]) {
        return false;
      }
    }

    return this.isUnique;
  }

  private sort(): number[] {
    return this.numbers.sort((a, b) => a - b);
  }

  private static filterUnique(
    value: number,
    index: number,
    numbers: number[],
  ): boolean {
    return numbers.indexOf(value) === index;
  }

  private get isUnique(): boolean {
    return this.numbers.filter(OrderedNumbers.filterUnique).length ===
      this.numbers.length;
  }

  private makeUnique(): number[] {
    this.numbers = this.numbers.filter(OrderedNumbers.filterUnique);

    return this.numbers;
  }

  public get list(): number[] {
    return this.numbers;
  }

  public get max(): number {
    return this.numbers.slice(-1)[0];
  }

  public contains(number: number): boolean {
    return this.numbers.indexOf(number) !== -1;
  }

  public add(number: number): number[] {
    if (this.unique && this.contains(number)) {
      return this.list;
    }

    const max = this.max;

    this.numbers.push(number);
    if (max < number) {
      return this.list;
    }

    this.sort();
    return this.list;
  }

  public remove(number: number): number[] {
    if (!this.contains(number)) {
      return this.list;
    }

    this.numbers = this.list.filter((n) => n !== number);

    return this.numbers;
  }

  public findNextLargerValue(
    number: number,
    fromIndex = 0,
    toIndex = this.numbers.length,
  ): number | undefined {
    if (this.list.length === 0) {
      return undefined;
    }

    if (number > this.max) {
      return undefined;
    }

    if (number < this.numbers[0]) {
      return this.numbers[0];
    }

    if (this.contains(number)) {
      return this.numbers[this.numbers.indexOf(number) + 1];
    }

    const length = toIndex - fromIndex;

    if (length > 1) {
      const middle = fromIndex + Math.floor(length / 2);

      return this.numbers[middle] > number
        ? this.findNextLargerValue(number, fromIndex, middle)
        : this.findNextLargerValue(number, middle + 1, toIndex);
    }

    return this.numbers[fromIndex] > number
      ? this.numbers[fromIndex]
      : this.numbers[fromIndex + 1];
  }
}