import {
  addToDeleteSet,
  StructStore, Item, Transaction // eslint-disable-line
} from '../internals.js'

import * as encoding from 'lib0/encoding.js'
import * as decoding from 'lib0/decoding.js'

/**
 * @private
 */
export class ContentDeleted {
  /**
   * @param {number} len
   */
  constructor (len) {
    this.len = len
  }

  /**
   * @return {number}
   */
  getLength () {
    return this.len
  }

  /**
   * @return {Array<any>}
   */
  getContent () {
    return []
  }

  /**
   * @return {boolean}
   */
  isCountable () {
    return false
  }

  /**
   * @return {ContentDeleted}
   */
  copy () {
    return new ContentDeleted(this.len)
  }

  /**
   * @param {number} offset
   * @return {ContentDeleted}
   */
  splice (offset) {
    const right = new ContentDeleted(this.len - offset)
    this.len = offset
    return right
  }

  /**
   * @param {ContentDeleted} right
   * @return {boolean}
   */
  mergeWith (right) {
    this.len += right.len
    return true
  }

  /**
   * @param {Transaction} transaction
   * @param {Item} item
   */
  integrate (transaction, item) {
    addToDeleteSet(transaction.deleteSet, item.id, this.len)
    item.deleted = true
  }

  /**
   * @param {Transaction} transaction
   */
  delete (transaction) {}
  /**
   * @param {StructStore} store
   */
  gc (store) {}
  /**
   * @param {encoding.Encoder} encoder
   * @param {number} offset
   */
  write (encoder, offset) {
    encoding.writeVarUint(encoder, this.len - offset)
  }

  /**
   * @return {number}
   */
  getRef () {
    return 1
  }
}

/**
 * @private
 *
 * @param {decoding.Decoder} decoder
 * @return {ContentDeleted}
 */
export const readContentDeleted = decoder => new ContentDeleted(decoding.readVarUint(decoder))