tree.ts

import type { CID } from "multiformats/cid"

import * as Check from "../types/check.js"
import * as Depot from "../../components/depot/implementation.js"
import * as Protocol from "../protocol/index.js"
import * as Link from "../link.js"

import { HardLinks, BaseLinks, Tree, File, Puttable, UpdateCallback, PuttableUnixTree } from "../types.js"
import { Maybe, decodeCID } from "../../common/index.js"
import { isObject, hasProp } from "../../common/type-checks.js"
import { Segments as Path } from "../../path/index.js"

import BareFile from "../bare/file.js"
import BaseTree from "../base/tree.js"


class BareTree extends BaseTree {

  depot: Depot.Implementation
  links: HardLinks
  children: { [ name: string ]: Tree | File }
  type: "BareTree"

  constructor(depot: Depot.Implementation, links: HardLinks) {
    super()
    this.type = "BareTree"
    this.links = links
    this.children = {}
    this.depot = depot
  }

  static async empty(depot: Depot.Implementation): Promise<BareTree> {
    return new BareTree(depot, {})
  }

  static async fromCID(depot: Depot.Implementation, cid: CID): Promise<BareTree> {
    const links = Link.arrToMap(
      (await depot.getUnixDirectory(cid))
    )

    return new BareTree(depot, links)
  }

  static fromLinks(depot: Depot.Implementation, links: HardLinks): BareTree {
    return new BareTree(depot, links)
  }

  static instanceOf(obj: unknown): obj is BareTree {
    return isObject(obj)
      && hasProp(obj, "links")
      && hasProp(obj, "children")
      && hasProp(obj, "type")
      && obj.type === "BareTree"
  }

  async createChildTree(name: string, onUpdate: Maybe<UpdateCallback>): Promise<Tree> {
    const child = await BareTree.empty(this.depot)

    const existing = this.children[ name ]
    if (existing) {
      if (Check.isFile(existing)) {
        throw new Error(`There is a file at the given path: ${name}`)
      }
      return existing
    }

    await this.updateDirectChild(child, name, onUpdate)
    return child
  }

  async createOrUpdateChildFile(content: Uint8Array, name: string, onUpdate: Maybe<UpdateCallback>): Promise<BareFile> {
    const existing = await this.getDirectChild(name)
    let file: BareFile
    if (existing === null) {
      file = await BareFile.create(this.depot, content)
    } else if (BareFile.instanceOf(existing)) {
      file = await existing.updateContent(content)
    } else {
      throw new Error(`There is already a directory with that name: ${name}`)
    }
    await this.updateDirectChild(file, name, onUpdate)
    return file
  }

  async putDetailed(): Promise<Depot.PutResult> {
    return Protocol.basic.putLinks(this.depot, this.links)
  }

  async putAndUpdateLink(child: Puttable, name: string, onUpdate: Maybe<UpdateCallback>): Promise<this> {
    const details = await child.putDetailed()
    this.updateLink(name, details)
    onUpdate && await onUpdate()
    return this
  }

  async updateDirectChild(child: Tree | File, name: string, onUpdate: Maybe<UpdateCallback>): Promise<this> {
    this.children[ name ] = child
    return this.putAndUpdateLink(child, name, onUpdate)
  }

  removeDirectChild(name: string): this {
    delete this.links[ name ]
    if (this.children[ name ]) {
      delete this.children[ name ]
    }
    return this
  }

  async getDirectChild(name: string): Promise<Tree | File | null> {
    if (this.children[ name ]) {
      return this.children[ name ]
    }

    const link = this.links[ name ] || null
    if (link === null) return null
    const cid = decodeCID(link.cid)
    const child = link.isFile
      ? await BareFile.fromCID(this.depot, cid)
      : await BareTree.fromCID(this.depot, cid)

    // check that the child wasn't added while retrieving the content from the network
    if (this.children[ name ]) {
      return this.children[ name ]
    }

    this.children[ name ] = child
    return child
  }

  async get(path: Path): Promise<Tree | File | null> {
    const [ head, ...nextPath ] = path

    if (!head) return this
    const nextTree = await this.getDirectChild(head)

    if (!nextPath.length) {
      return nextTree
    } else if (nextTree === null || Check.isFile(nextTree)) {
      return null
    }

    return nextTree.get(nextPath)
  }

  updateLink(name: string, result: Depot.PutResult): this {
    const { cid, size, isFile } = result
    this.links[ name ] = Link.make(name, cid, isFile, size)
    return this
  }

  getLinks(): BaseLinks {
    return this.links
  }
}


export default BareTree