// taken from https://github.com/hzrd149/nostrudel

import {nip19, verifyEvent} from "nostr-tools";
import createDefer, {Deferred} from "./classes/deffered";
import {getPubkeyFromDecodeResult, isHexKey} from "./helpers/nip19";
import {NostrEvent} from "./types/nostr-event";

export function createGetPublicKeyIntent() {
  return `nostrsigner:?compressionType=none&returnType=signature&type=get_public_key`;
}
export function createSignEventIntent(draft) {
  return `nostrsigner:${encodeURIComponent(
    JSON.stringify(draft),
  )}?compressionType=none&returnType=event&type=sign_event`;
}

let pendingRequest: Deferred<string> | null = null;

function rejectPending() {
  if (pendingRequest) {
    pendingRequest.reject("Canceled");
    pendingRequest = null;
  }
}

export function createNip04EncryptIntent(pubkey: string, plainText: string) {
  return `nostrsigner:${encodeURIComponent(
    plainText,
  )}?pubKey=${pubkey}&compressionType=none&returnType=signature&type=nip04_encrypt`;
}
export function createNip04DecryptIntent(pubkey: string, data: string) {
  return `nostrsigner:${encodeURIComponent(
    data,
  )}?pubKey=${pubkey}&compressionType=none&returnType=signature&type=nip04_decrypt`;
}


async function nip04Encrypt(pubkey: string, plaintext: string): Promise<string> {
  return await intentRequest(createNip04EncryptIntent(pubkey, plaintext));
}
async function nip04Decrypt(pubkey: string, data: string): Promise<string> {
  return await intentRequest(createNip04DecryptIntent(pubkey, data));
}


function onVisibilityChange() {
  if (document.visibilityState === "visible") {
    if (!pendingRequest || !navigator.clipboard) return;

    // read the result from the clipboard
    setTimeout(() => {
      navigator.clipboard
        .readText()
        .then((result) => pendingRequest?.resolve(result))
        .catch((e) => pendingRequest?.reject(e));
    }, 200);
  }
}
document.addEventListener("visibilitychange", onVisibilityChange);

async function intentRequest(intent: string) {
  rejectPending();
  const request = createDefer<string>();
  window.open(intent, "_blank");
  // NOTE: wait 500ms before setting the pending request since the visibilitychange event fires as soon as window.open is called
  setTimeout(() => {
    pendingRequest = request;
  }, 500);
  const result = await request;
  if (result.length === 0) throw new Error("Empty clipboard");
  return result;
}

async function getPublicKey() {
  const result = await intentRequest(createGetPublicKeyIntent());
  if (isHexKey(result)) return result;
  else if (result.startsWith("npub") || result.startsWith("nprofile")) {
    const decode = nip19.decode(result);
    const pubkey = getPubkeyFromDecodeResult(decode);
    if (!pubkey) throw new Error("Expected npub from clipboard");
    return pubkey;
  }
  throw new Error("Expected clipboard to have pubkey");
}

async function signEvent(draft): Promise<NostrEvent> {
  const signedEventJson = await intentRequest(createSignEventIntent(draft));
  const signedEvent = JSON.parse(signedEventJson) as NostrEvent;

  if (!verifyEvent(signedEvent)) throw new Error("Invalid signature");
  return signedEvent;
}

const amberSignerService = {
  supported: navigator.userAgent.includes("Android") && navigator.clipboard,
  getPublicKey,
  signEvent,
  nip04Encrypt,
  nip04Decrypt,
};

export default amberSignerService;