fission-suite/webnative

import * as DagCBOR from "@ipld/dag-cbor"
import * as Uint8arrays from "uint8arrays"

import * as Crypto from "../components/crypto/implementation.js"
import * as Depot from "../components/depot/implementation.js"
import * as Manners from "../components/manners/implementation.js"
import * as Reference from "../components/reference/implementation.js"
import * as Path from "../path/index.js"

import * as Basic from "./protocol/basic.js"
import * as Protocol from "./protocol/index.js"
import * as EntryIndex from "./protocol/shared/entry-index.js"
import * as ShareKey from "./protocol/shared/key.js"

import { RootBranch } from "../path/index.js"
import { SharedBy, ShareDetails } from "./types.js"
import { SymmAlg } from "../components/crypto/implementation.js"
import { decodeCID, encodeCID } from "../common/cid.js"
import { didToPublicKey } from "../did/transformers.js"

import BareTree from "./bare/tree.js"
import PrivateFile from "./v1/PrivateFile.js"
import PrivateTree from "./v1/PrivateTree.js"
import RootTree from "./root/tree.js"


// CONSTANTS


export const EXCHANGE_PATH: Path.Directory<Path.PartitionedNonEmpty<Path.Public>> = Path.directory(
  "public",
  ".well-known",
  "exchange"
)



// FUNCTIONS


export async function privateNode(
  crypto: Crypto.Implementation,
  depot: Depot.Implementation,
  manners: Manners.Implementation,
  reference: Reference.Implementation,
  rootTree: RootTree,
  items: Array<[ string, PrivateTree | PrivateFile ]>,
  { shareWith, sharedBy }: {
    shareWith: string | string[]
    sharedBy: SharedBy
  }
): Promise<ShareDetails> {
  const exchangeDIDs = Array.isArray(shareWith)
    ? shareWith
    : shareWith.startsWith("did:")
      ? [ shareWith ]
      : await listExchangeDIDs(depot, reference, shareWith)

  const counter = rootTree.sharedCounter || 1
  const mmpt = rootTree.mmpt

  // Create share keys
  const shareKeysWithDIDs: [ string, ShareKey.ShareKey ][] = await Promise.all(exchangeDIDs.map(async did => {
    return [
      did,
      await ShareKey.create(crypto, {
        counter,
        recipientExchangeDid: did,
        senderRootDid: sharedBy.rootDid
      })
    ] as [ string, ShareKey.ShareKey ]
  }))

  // Create entry index
  const indexKey = await crypto.aes.genKey(SymmAlg.AES_GCM).then(crypto.aes.exportKey)
  const index = await PrivateTree.create(crypto, depot, manners, reference, mmpt, indexKey, null)

  await Promise.all(
    items.map(async ([ name, item ]) => {
      const privateName = await item.getName()
      return index.insertSoftLink({
        key: item.key,
        name,
        privateName,
        username: sharedBy.username
      })
    })
  )

  // Add entry index to depot
  const symmKeyAlgo = SymmAlg.AES_GCM
  const indexNode = Object.assign({}, index.header)
  const indexResult = await Basic.putFile(
    depot,
    await crypto.aes.encrypt(
      Uint8arrays.fromString(JSON.stringify(indexNode), "utf8"),
      index.key,
      symmKeyAlgo
    )
  )

  // Add entry index CID to MMPT
  if (shareKeysWithDIDs.length) {
    const namefilter = await EntryIndex.namefilter(crypto, {
      bareFilter: indexNode.bareNameFilter,
      shareKey: shareKeysWithDIDs[ 0 ][ 1 ]
    })

    await mmpt.add(namefilter, indexResult.cid)
  }

  // Create share payload
  const payload = DagCBOR.encode(ShareKey.payload({
    entryIndexCid: encodeCID(indexResult.cid),
    symmKey: index.key,
    symmKeyAlgo
  }))

  // Add encrypted payloads to depot
  const links = await Promise.all(shareKeysWithDIDs.map(async ([ did, shareKey ]) => {
    const { publicKey } = didToPublicKey(crypto, did)
    const encryptedPayload = await crypto.rsa.encrypt(payload, publicKey)
    const result = await depot.putChunked(encryptedPayload)

    return {
      name: shareKey,
      cid: result.cid,
      size: result.size
    }
  }))

  // Add shares to filesystem
  await rootTree.addShares(links)

  // Fin
  return { shareId: counter.toString(), sharedBy }
}


export async function listExchangeDIDs(
  depot: Depot.Implementation,
  reference: Reference.Implementation,
  username: string) {
  const root = await reference.dataRoot.lookup(username)
  if (!root) throw new Error("This person doesn't have a filesystem yet.")

  const rootLinks = await Protocol.basic.getSimpleLinks(depot, root)
  const prettyTreeCid = rootLinks[ RootBranch.Pretty ]?.cid || null
  if (!prettyTreeCid) throw new Error("This person's filesystem doesn't have a pretty tree.")

  const tree = await BareTree.fromCID(depot, decodeCID(prettyTreeCid))
  const exchangePath = Path.unwrap(Path.removePartition(EXCHANGE_PATH))
  const exchangeTree = await tree.get(exchangePath)

  return exchangeTree && exchangeTree instanceof BareTree
    ? Object.keys(exchangeTree.getLinks())
    : []
}