export class WrappedBuffer {
  #raw: Uint8Array
  #length: number

  constructor(buffer?: Uint8Array) {
    this.#raw = buffer ? new Uint8Array(buffer) : new Uint8Array(512)
    this.#length = buffer ? buffer.length : 0
  }

  unwrap() {
    return this.#raw.subarray(0, this.#length)
  }

  get capacity() {
    return this.#raw.byteLength
  }

  get length() {
    return this.#length
  }

  set(val: ArrayLike<number>, offset?: number) {
    this.#raw.set(val, offset)
    this.#length = (offset ?? 0) + val.length
  }

  append(val: ArrayLike<number>) {
    const targetSize = val.length + this.#length
    this.resize(targetSize)

    this.#raw.set(val, this.#length)
    this.#length += val.length
  }

  clear() {
    this.#length = 0
    this.#raw.fill(0)
  }

  resize(newSize: number) {
    if (this.capacity < newSize) {
      const newCapacity = Math.max(this.capacity * 2, newSize)
      const newArr = new Uint8Array(newCapacity)
      newArr.set(this.#raw)
      this.#raw = newArr
    }
  }

  shift() {
    const first = this.#raw[0]
    this.#raw = this.#raw.subarray(1)
    this.#length--
    return first
  }

  shiftN(n = 1) {
    const firstSubarray = this.#raw.subarray(0, n)
    this.#raw = this.#raw.subarray(n)
    this.#length -= n
    return firstSubarray
  }
}