import { RepositorySearchResultItem } from '../../api/api'

interface CacheWrapper<T> {
  [keyword:string]:Caches<T>
}

interface Caches<T> {
  total_page:number
  list:{[page:number]:T[]}
}

const cache:CacheWrapper<RepositorySearchResultItem> = {}

export function RepositorySearchCache (keyword:string, max_cache_count:number) {
  if (!cache[keyword]) {
    cache[keyword] = {
      list: [],
      total_page: 0
    }
  }

  const _cache = cache[keyword]
  const _cache_list = _cache.list

  return {

    /**
     * 读取指定页码的缓存
     * @param {number} page 页码
     * @returns {RepositorySearchResultItem[]|undefined}
     */
    read (page:number):RepositorySearchResultItem[]|undefined {
      return _cache_list[page]
    },

    /**
     * 添加指定页码的缓存
     * @param {number} page 页码
     * @param {RepositorySearchResultItem[]} data 缓存数据
     * @returns {this}
     */
    add (page:number, data:RepositorySearchResultItem[]) {
      if (!_cache_list[page] && this.getCount() >= max_cache_count) {
        this.remove(
          parseInt(Object.keys(_cache_list).shift()!, 10)
        )
      }
      _cache_list[page] = data
      return this
    },

    /**
     * 移除指定页码的缓存
     * @param {number} page 页码
     * @returns {this}
     */
    remove (page:number) {
      delete _cache_list[page]
      return this
    },

    /**
     * 更新页码总数的缓存
     * @param {number} total 页码总数
     * @returns {this}
     */
    updateTotalPage (total:number) {
      _cache.total_page = total
      return this
    },

    /**
     * 获取页码总数缓存
     * @returns {number}
     */
    getTotalPage ():number {
      return _cache.total_page
    },

    /**
     * 获取当前缓存总数
     * @returns {number}
     */
    getCount ():number {
      return Object.keys(_cache_list).length
    }
  }
}