import { EventTarget } from "./event-target";
import { messageFrom, Message, TypeMessage } from "./message";
import { RPCError } from "./rpc-error";
import SockJS from 'sockjs-client';

const EventTypeMessage = "message";
const EdgeAuth = "edge-auth"
const EdgeAuthTokenRequest = "edge_auth_token_request"
const EdgeAuthTokenResponse = "edge_auth_token_reponse"

export class Client extends EventTarget {

  _conn: any
  _rpcID: number
  _pendingRPC: {}
  _queue: Message[]
  _reconnectionDelay: number
  _autoReconnect: boolean
  debug: boolean

  constructor(autoReconnect = true) {
    super();
    this._conn = null;

    this._onConnectionClose = this._onConnectionClose.bind(this);
    this._onConnectionMessage = this._onConnectionMessage.bind(this);
    this._handleRPCResponse = this._handleRPCResponse.bind(this);
    this._handleEdgeAuthTokenRequest = this._handleEdgeAuthTokenRequest.bind(this);

    this._rpcID = 0;
    this._pendingRPC = {};
    this._queue = [];
    this._reconnectionDelay = 250;
    this._autoReconnect = autoReconnect;
    this.debug = false;

    this.connect = this.connect.bind(this);
    this.disconnect = this.disconnect.bind(this);
    this.rpc = this.rpc.bind(this);
    this.send = this.send.bind(this);
    this.upload = this.upload.bind(this);
    

    this.addEventListener(EventTypeMessage, this._handleRPCResponse);
    window.addEventListener('message', this._handleEdgeAuthTokenRequest);
  }

  connect(token = ""): Promise<Client> {
    let getToken: Promise<string>

    if (token) {
      getToken = Promise.resolve(token)
    } else {
      getToken = this._retrieveToken()
    }

    return getToken.then(token => this._connect(token))
  }

  disconnect() {
    this._cleanupConnection();
  }

  _connect(token: string): Promise<Client> {
    return new Promise((resolve, reject) => {
      const url = `//${document.location.host}/edge/sock?${EdgeAuth}=${token}`;
        this._log("opening connection to", url);
        const conn: any = new SockJS(url);

        const onOpen = () => {
          this._log('client connected');
          resetHandlers();
          conn.onclose = this._onConnectionClose;
          conn.onmessage = this._onConnectionMessage;
          this._conn = conn;
          this._sendQueued();
          setTimeout(() => {
            this._dispatchConnect();
          }, 0);
          return resolve(this);
        };

        const onError = (evt) => {
          resetHandlers();
          this._scheduleReconnection();
          return reject(evt);
        };

        const resetHandlers = () => {
          conn.removeEventListener('open', onOpen);
          conn.removeEventListener('close', onError);
          conn.removeEventListener('error', onError);
        };

        conn.addEventListener('open', onOpen);
        conn.addEventListener('error', onError);
        conn.addEventListener('close', onError);
    })
  }

  _retrieveToken(): Promise<string> {
    let token = this._getAuthCookieToken();
    if (token) {
      return Promise.resolve(token);
    }

    return this._getParentFrameToken();;
  }

  _getAuthCookieToken(): string {
    const cookie = document.cookie.split("; ")
      .find((row) => row.startsWith(EdgeAuth));

    let token = "";

    if (cookie) {
      token = cookie.split("=")[1];
    }

    return token;
  }

  _getParentFrameToken(timeout = 5000): Promise<string> {
    if (!window.parent || window.parent === window) {
      return Promise.resolve("");
    }

    return new Promise((resolve, reject) => {
      let timedOut = false;
      const timeoutId = setTimeout(() => {
        timedOut = true;
        reject(new Error("Edge auth token request timed out !"));
      }, timeout);

      const listener = (evt) => {
        const message = evt.data;

        if (!message || !message.type || !message.data) {
          return
        }

        if (message.type !== EdgeAuthTokenResponse) {
          return;
        }

        window.removeEventListener('message', listener);
        clearTimeout(timeoutId);

        if (timedOut) return;

        if (!message.data || !message.data.token) {
          reject("Unexpected auth token request response !");
          return;
        }

        resolve(message.data.token);
      }

      window.addEventListener('message', listener);
      
      const message = { type: EdgeAuthTokenRequest };
      window.parent.postMessage(message, '*');
    })
  }

  _handleEdgeAuthTokenRequest(evt: MessageEvent) {
    const message = evt.data;
    if (!message || !message.type || message.type !== EdgeAuthTokenRequest) {
      return;
    }

    if (!evt.source) {
      return;
    }

    const token = this._getAuthCookieToken();
    // @ts-ignore
    evt.source.postMessage({ type: EdgeAuthTokenResponse, data: { token }}, evt.origin);
  }

  _onConnectionMessage(evt) {
    const rawMessage = JSON.parse(evt.data);
    const message = messageFrom(rawMessage);
    const event = new CustomEvent(message.getType(), {
      cancelable: true,
      detail: message.getPayload()
    });
    this.dispatchEvent(event);
  }

  _handleRPCResponse(evt) {
    const { jsonrpc, id, error, result } = evt.detail;

    if (jsonrpc !== '2.0' || id === undefined) return;
    if (!evt.detail.hasOwnProperty("error") && !evt.detail.hasOwnProperty("result")) return;

    // Prevent additional handlers to catch this event
    evt.stopImmediatePropagation();

    const pending = this._pendingRPC[id];
    if (!pending) return;

    delete this._pendingRPC[id];

    if (error) {
      pending.reject(new RPCError(error.code, error.message, error.data));
      return;
    }

    pending.resolve(result);
  }

  _onConnectionClose(evt) {
    this._log('client disconnected');
    this._dispatchDisconnect();
    this._cleanupConnection();
    this._scheduleReconnection();
  }

  _dispatchDisconnect() {
    const event = new CustomEvent('disconnect');
    this.dispatchEvent(event);
  }

  _dispatchConnect() {
    const event = new CustomEvent('connect');
    this.dispatchEvent(event);
  }

  _scheduleReconnection() {
    if (!this._autoReconnect) return;

    this._reconnectionDelay = this._reconnectionDelay * 2 + Math.random();
    this._log('client will try to reconnect in %dms', this._reconnectionDelay);
    setTimeout(this.connect.bind(this), this._reconnectionDelay);
  }

  _cleanupConnection() {
    if (!this._conn) return;
    this._conn.onopen = null;
    this._conn.onerror = null;
    this._conn.onclose = null;
    this._conn.onmessage = null;
    this._conn.close();
    this._conn = null;
  }

  _send(message) {
    if (!this._conn) return false;
    this._log('sending message', message);
    this._conn.send(JSON.stringify(message));
    return true;
  }

  _sendQueued() {
    this._log("sending queued messages", this._queue.length);
    let msg = this._queue.shift();
    while (msg) {
      const sent = this._send(msg);
      if (!sent) return;
      msg = this._queue.shift();
    }
  }

  _log(...args) {
    if (!this.debug) return;
    console.log(...args);
  }

  _sendOrQueue(msg) {
    if (this.isConnected()) {
      this._sendQueued();
      this._send(msg);
    } else {
      this._log('queuing message', msg);
      this._queue.push(msg);
    }
  }

  send(data) {
    const msg = new Message(TypeMessage, data);
    this._sendOrQueue(msg);
  }

  rpc(method, params) {
    return new Promise((resolve, reject) => {
      const id = this._rpcID++;
      const rpc = new Message(TypeMessage, {
        jsonrpc: '2.0',
        id, method, params
      });
      this._sendOrQueue(rpc);
      this._pendingRPC[id.toString()] = { resolve, reject };
    });
  }

  isConnected() {
    return this._conn !== null;
  }

  upload(blob: string | Blob, metadata: any) {
    return new Promise((resolve, reject) => {
      const formData = new FormData();
      formData.set("file", blob);

      if (metadata) {
        try {
          formData.set("metadata", JSON.stringify(metadata));
        } catch (err) {
          return reject(err);
        }
      }
      const xhr = new XMLHttpRequest();

      const result = {
        onProgress: null,
        abort: () => xhr.abort(),
        result: () => {
          return new Promise((resolve, reject) => {
            xhr.onload = () => {
              let data;
              try {
                data = JSON.parse(xhr.responseText);
              } catch (err) {
                reject(err);
                return;
              }
              resolve(data);
            };
            xhr.onerror = reject;
            xhr.onabort = reject;
          });
        }
      };

      xhr.upload.onprogress = evt => {
        if (typeof result.onProgress !== 'function') return;
        (result as any).onProgress(evt.loaded, evt.total);
      };
      xhr.onabort = reject;
      xhr.onerror = reject;

      xhr.open('POST', `/edge/api/v1/upload`);
      xhr.send(formData);

      resolve(result);
    });
  }

  blobUrl(bucket: string, blobId: string): string {
    return `/edge/api/v1/download/${bucket}/${blobId}`;
  }

  externalUrl(url: string): string {
    return `/edge/api/v1/fetch?url=${encodeURIComponent(url)}`
  }
}