/**
 * Detection and global state for sporran wallet
 *
 * Detect wallet in a component's mounted() and updated() hooks with: this.$wallet.checkForExtension()
 *
 * Use the wallet with: this.$wallet.getInstance()
 */

import Vue from "vue";
// import { DidPublicKey, IEncryptedMessage } from '@kiltprotocol/sdk-js'

function walletSetup() {
  let instance = null;

  // #region helpers
  /**
   * Helpers for getting extension object from window
   *
   * @docs https://hackmd.io/@dTGKTsAWSxi6eYV5aeFnXA/ryH5JVCd5
   */

  const apiWindow = window;

  /**
   * @param {() => Promise<T>} creator
   * @returns {Promise<T>}
   */
  function documentReadyPromise(creator) {
    return new Promise((resolve) => {
      if (document.readyState === "complete") {
        resolve(creator());
      } else {
        window.addEventListener("load", () => resolve(creator()));
      }
    });
  }

  /**
   * @returns {Promise<[{ name?: string; signWithDid: ( plaintext: string ) => Promise<{ signature: string; didKeyUri: string }>; startSession: ( dAppName: string, dAppEncryptionKeyId: DidPublicKey['id'], challenge: string ) => Promise<{ listen: ( callback: (message: IEncryptedMessage) => Promise<void> ) => Promise<void>; close: () => Promise<void>; send: (message: IEncryptedMessage) => Promise<void>; encryptionKeyId: DidPublicKey['id']; encryptedChallenge: string; nonce: string; }>; specVersion: '0.1'; version: string; }][]>}
   */
  function getWindowExtensions() {
    return Promise.all(
      Object.entries(apiWindow.kilt).map(
        ([name, { version, signWithDid, startSession, specVersion }]) =>
          Promise.all([
            Promise.resolve({
              name,
              version,
              signWithDid,
              startSession,
              specVersion,
            }),
          ])
      )
    );
  }

  /**
   * @returns {Promise<{ name?: string; signWithDid: ( plaintext: string ) => Promise<{ signature: string; didKeyUri: string }>; startSession: ( dAppName: string, dAppEncryptionKeyId: DidPublicKey['id'], challenge: string ) => Promise<{ listen: ( callback: (message: IEncryptedMessage) => Promise<void> ) => Promise<void>; close: () => Promise<void>; send: (message: IEncryptedMessage) => Promise<void>; encryptionKeyId: DidPublicKey['id']; encryptedChallenge: string; nonce: string; }>; specVersion: '0.1'; version: string; }[]>}}
   */
  function getExtensions() {
    apiWindow.kilt = apiWindow.kilt || {};

    return documentReadyPromise(() =>
      getWindowExtensions()
        .then((values) =>
          values.filter((value) => !!value[0]).map(([info]) => info)
        )
        .catch(() => [])
        .then((values) => values)
    );
  }
  // #endregion

  async function checkForExtension() {
    const allInjected = await getExtensions();

    if (Array.isArray(allInjected) && allInjected.length) {
      allInjected.forEach((x) => {
        if (x.name === "sporran") {
          instance = x;
        }
      });
    }
  }

  function getInstance() {
    return instance;
  }

  return {
    checkForExtension,
    getInstance,
  };
}

export default function (app) {
  Vue.prototype.$wallet = walletSetup();
}