import type { Json, ObjectStorage } from '../common/types'
import { jsonStringifySafe } from '../common/data/json'

export interface LocalStorageOptions {
  name: string
  objectFromString?: (data: string) => any
  objectToString?: (data: any) => string
}

export class LocalStorage<T = Json> implements ObjectStorage<T> {
  private name: string
  private prefix: string
  private pretty = false
  private objectFromString: (data: string) => any
  private objectToString: (data: any) => string

  constructor(opt: LocalStorageOptions) {
    this.name = opt.name ?? 'zeed'
    this.prefix = `${opt.name}$`
    this.objectToString = opt.objectToString ?? ((data: any): string => {
      return this.pretty
        ? jsonStringifySafe(data, null, 2)
        : jsonStringifySafe(data)
    })

    this.objectFromString = opt.objectFromString ?? ((data: string) => {
      try {
        return JSON.parse(data)
      }
      catch (err) {
        // log.warn(`LocalStorage parse error '${err}' in`, data)
      }
    })
  }

  setItem(key: string, value: T): void {
    const data = this.objectToString(value)
    localStorage.setItem(`${this.prefix}${key}`, data)
  }

  getItem(key: string): T | undefined {
    const value = localStorage.getItem(`${this.prefix}${key}`)
    if (value != null)
      return this.objectFromString(value)
  }

  removeItem(key: string): void {
    localStorage.removeItem(`${this.prefix}${key}`)
  }

  clear(): void {
    Object.keys(localStorage).filter(key => key.startsWith(this.prefix)).forEach((key) => {
      localStorage.removeItem(key)
    })
  }

  allKeys(): string[] {
    const prefixLength = this.prefix.length
    return Object.keys(localStorage).filter(key => key.startsWith(this.prefix)).map(key => key.substr(prefixLength))
  }
}