import { Component, OnDestroy, OnInit, ChangeDetectorRef, ElementRef, ViewChild } from '@angular/core';
import { DeploymentNotificationService } from '../services/deployment-notification.service';
import { Subscription, BehaviorSubject } from 'rxjs';
import { WebSocketService } from '../services/websocket.service';
import { WebSocketMessage } from '../message-types/websocket-message';
import { DashboardConfigService } from '../services/config.service';
import { HttpClient } from '@angular/common/http';
import { delay, retryWhen, tap } from 'rxjs/operators';
import { FSMUpdateService } from '../services/fsmupdate.service';
import { MessagesComponent } from '../messages/messages.component';

@Component({
  selector: 'app-dashboard',
  templateUrl: './dashboard.component.html',
  styleUrls: ['./dashboard.component.scss']
})
export class DashboardComponent implements OnInit, OnDestroy {
  deploying = false;
  polling = new BehaviorSubject<boolean>(false);
  deploymentNotificationSubscription: Subscription;
  @ViewChild('webiframe', {static: false}) webiframe: ElementRef;
  @ViewChild(MessagesComponent, {static: false}) messages: MessagesComponent;
  @ViewChild('urlbar', {static: false}) urlbar: ElementRef;

  layout = this.configService.layout;
  hideMessages = this.configService.hideMessages;
  showUrlBar = this.configService.showUrlBar;
  iframeUrl = this.configService.iframeUrl;
  actualIframeUrl = this.iframeUrl.value;
  terminalMenuItem = this.configService.terminalMenuItem;
  iframeReloadSubscription: Subscription;

  command_handlers = {
    'dashboard.reloadFrontend':   this.reloadFrontendHandlder.bind(this),
    'dashboard.reloadIframe':     this.reloadIframeHandler.bind(this)
  };

  constructor(private deploymentNotificationService: DeploymentNotificationService,
              private webSocketService: WebSocketService,
              private changeDetectorRef: ChangeDetectorRef,
              private http: HttpClient,
              private configService: DashboardConfigService,
              private fsmUpdateService: FSMUpdateService) {}

  ngOnInit() {
    this.webSocketService.connect();
    this.configService.init();
    this.subscribeCheckSolution();
    this.hideIframeUntilResponseOk();
    this.subscribeResizeOnLayoutChange();
    this.initCommandHandling();
    this.initDeploymentNotifications();
    this.sendReady();
  }

  subscribeCheckSolution() {
    this.fsmUpdateService.init();
    this.fsmUpdateService.in_accepted_state.subscribe(in_accepted_state => {
      if (in_accepted_state) {
        window.parent.postMessage('check solution', '*');
      }
    });
  }

  hideIframeUntilResponseOk() {
    // TODO: hide iframe and show it after this whole deal...
    this.reloadIframeWhenResponseOk();
  }

  subscribeResizeOnLayoutChange() {
    this.configService.layout.subscribe(() => {
      this.emitResizeEvent();
      setTimeout(() => this.messages.scrollToBottom(), 0);
    });
  }

  initCommandHandling() {
    this.webSocketService.observeControl<WebSocketMessage>('dashboard').subscribe(message => {
      this.command_handlers[message.key](message);
      this.changeDetectorRef.detectChanges();
    });
  }

  initDeploymentNotifications() {
    this.deploymentNotificationSubscription = this.deploymentNotificationService.deploying.subscribe(
      (deploying) => {
        this.deploying = deploying;
        if (!deploying && this.configService.reloadIframeOnDeploy.value) {
          this.reloadIframeWhenResponseOk();
        }
      });
  }

  sendReady() {
    setTimeout(() => this.webSocketService.send({'key': 'frontend.ready'}));
  }

  reloadFrontendHandlder(message: WebSocketMessage) {
    setTimeout(() => window.location.reload(), 2000);
  }

  reloadIframeHandler(message: WebSocketMessage) {
    setTimeout(() => this.reloadIframeNoSubmit(), 200);
  }

  setLayout(layout: string) {
    this.layout.next(layout);
  }

  emitResizeEvent() {
    // We need to trigger a 'resize' event manually, otherwise editor stays collapsed
    // editor 'resize' event listener requires a parameter of force=true
    setTimeout(() => window.dispatchEvent(new Event('resize', {force: true} as any)), 0);
  }

  reloadIframe() {
    setTimeout(() => {
      this.webiframe.nativeElement.contentWindow.location.reload(true);
    });
  }

  reloadIframeNoSubmit() {
    // Sometimes it is needed to reload the iframe without resending the previous form data
    setTimeout(() => {
      this.webiframe.nativeElement.contentWindow.location = this.webiframe.nativeElement.contentWindow.location.href;
    });
  }

  selectTerminalMenuItem(item: string) {
    if (!item.match('(terminal|console)')) {
      return;
    }
    this.terminalMenuItem.next(item);
  }

  iframeLoad() {
    if (this.webiframe && this.iframeUrl.value) {
      const href = this.webiframe.nativeElement.contentWindow.frames.location.href;
      const match = href.match(/.*?\/\/.*?(\/.*)/);
      if (match !== null) {
        // iframes on Firefox can have an about:blank
        // contentWindow after firing a (load) event
        const niceURL = match[1];
        this.actualIframeUrl = niceURL;
      }
    }
  }

  changeIframeURL() {
    const userGivenValue = this.urlbar.nativeElement.value.trim();
    if (
        userGivenValue === '/' ||
        userGivenValue.startsWith('dashboard') ||
        userGivenValue.startsWith('/dashboard')
    ) {
      return;
    }
    this.webiframe.nativeElement.contentWindow.frames.location.href = this.urlbar.nativeElement.value;
  }

  reloadIframeWhenResponseOk() {
    if (this.polling.value) {
      this.iframeReloadSubscription.unsubscribe();
    }
    this.polling.next(true);
    this.iframeReloadSubscription = this.http.get(this.actualIframeUrl, {observe: 'response'}).pipe(
      retryWhen(errors =>
        errors.pipe(
          tap(
            response => {
              if (response.status === 200) {
                this.iframeReloadSubscription.unsubscribe();
                this.polling.next(false);
                this.reloadIframe();
          }}),
          delay(1000)
    ))).subscribe();
  }

  ngOnDestroy() {
    if (this.deploymentNotificationSubscription) {
      this.deploymentNotificationSubscription.unsubscribe();
    }

    if (this.iframeReloadSubscription) {
      this.iframeReloadSubscription.unsubscribe();
    }
  }
}