///
/// Copyright © 2016-2020 The Thingsboard Authors
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
///     http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///

import {
  AfterViewInit,
  Component,
  ElementRef,
  EventEmitter,
  Input,
  NgZone,
  OnInit,
  ViewChild,
  ViewContainerRef
} from '@angular/core';
import { PageComponent } from '@shared/components/page.component';
import { Store } from '@ngrx/store';
import { AppState } from '@core/core.state';
import { WidgetAction, WidgetContext } from '@home/models/widget-component.models';
import { Datasource, WidgetActionDescriptor, WidgetConfig } from '@shared/models/widget.models';
import { IWidgetSubscription } from '@core/api/widget-api.models';
import { UtilsService } from '@core/services/utils.service';
import { TranslateService } from '@ngx-translate/core';
import { deepClone, isDefined, isNumber, createLabelFromDatasource, hashCode } from '@core/utils';
import cssjs from '@core/css/css';
import { PageLink } from '@shared/models/page/page-link';
import { Direction, SortOrder, sortOrderFromString } from '@shared/models/page/sort-order';
import { CollectionViewer, DataSource, SelectionModel } from '@angular/cdk/collections';
import { BehaviorSubject, forkJoin, fromEvent, merge, Observable, of } from 'rxjs';
import { emptyPageData, PageData } from '@shared/models/page/page-data';
import { entityTypeTranslations } from '@shared/models/entity-type.models';
import { catchError, debounceTime, distinctUntilChanged, map, take, tap } from 'rxjs/operators';
import { MatPaginator } from '@angular/material/paginator';
import { MatSort } from '@angular/material/sort';
import { DomSanitizer, SafeHtml } from '@angular/platform-browser';
import {
  CellContentInfo,
  CellStyleInfo,
  constructTableCssString,
  DisplayColumn,
  EntityColumn,
  fromAlarmColumnDef,
  getAlarmValue,
  getCellContentInfo,
  getCellStyleInfo,
  getColumnWidth,
  TableWidgetDataKeySettings,
  TableWidgetSettings,
  toAlarmColumnDef,
  widthStyle
} from '@home/components/widget/lib/table-widget.models';
import { ConnectedPosition, Overlay, OverlayConfig, OverlayRef } from '@angular/cdk/overlay';
import { ComponentPortal, PortalInjector } from '@angular/cdk/portal';
import {
  DISPLAY_COLUMNS_PANEL_DATA,
  DisplayColumnsPanelComponent,
  DisplayColumnsPanelData
} from '@home/components/widget/lib/display-columns-panel.component';
import {
  alarmFields,
  AlarmInfo,
  alarmSeverityColors,
  alarmSeverityTranslations,
  AlarmStatus,
  alarmStatusTranslations
} from '@shared/models/alarm.models';
import { DatePipe } from '@angular/common';
import {
  ALARM_STATUS_FILTER_PANEL_DATA,
  AlarmStatusFilterPanelComponent,
  AlarmStatusFilterPanelData
} from '@home/components/widget/lib/alarm-status-filter-panel.component';
import {
  AlarmDetailsDialogComponent,
  AlarmDetailsDialogData
} from '@home/components/alarm/alarm-details-dialog.component';
import { MatDialog } from '@angular/material/dialog';
import { NULL_UUID } from '@shared/models/id/has-uuid';
import { DialogService } from '@core/services/dialog.service';
import { AlarmService } from '@core/http/alarm.service';

interface AlarmsTableWidgetSettings extends TableWidgetSettings {
  alarmsTitle: string;
  enableSelection: boolean;
  enableStatusFilter: boolean;
  enableStickyAction: boolean;
  displayDetails: boolean;
  allowAcknowledgment: boolean;
  allowClear: boolean;
}

interface AlarmWidgetActionDescriptor extends WidgetActionDescriptor {
  details?: boolean;
  acknowledge?: boolean;
  clear?: boolean;
}

@Component({
  selector: 'tb-alarms-table-widget',
  templateUrl: './alarms-table-widget.component.html',
  styleUrls: ['./alarms-table-widget.component.scss', './table-widget.scss']
})
export class AlarmsTableWidgetComponent extends PageComponent implements OnInit, AfterViewInit {

  @Input()
  ctx: WidgetContext;

  @ViewChild('searchInput') searchInputField: ElementRef;
  @ViewChild(MatPaginator) paginator: MatPaginator;
  @ViewChild(MatSort) sort: MatSort;

  public enableSelection = true;
  public displayPagination = true;
  public enableStickyAction = false;
  public pageSizeOptions;
  public pageLink: PageLink;
  public sortOrderProperty: string;
  public textSearchMode = false;
  public columns: Array<EntityColumn> = [];
  public displayedColumns: string[] = [];
  public actionCellDescriptors: AlarmWidgetActionDescriptor[] = [];
  public alarmsDatasource: AlarmsDatasource;

  private settings: AlarmsTableWidgetSettings;
  private widgetConfig: WidgetConfig;
  private subscription: IWidgetSubscription;
  private alarmSource: Datasource;

  private displayDetails = true;
  private allowAcknowledgment = true;
  private allowClear = true;

  private defaultPageSize = 10;
  private defaultSortOrder = '-' + alarmFields.createdTime.value;

  private contentsInfo: {[key: string]: CellContentInfo} = {};
  private stylesInfo: {[key: string]: CellStyleInfo} = {};
  private columnWidth: {[key: string]: string} = {};

  private searchAction: WidgetAction = {
    name: 'action.search',
    show: true,
    icon: 'search',
    onAction: () => {
      this.enterFilterMode();
    }
  };

  private columnDisplayAction: WidgetAction = {
    name: 'entity.columns-to-display',
    show: true,
    icon: 'view_column',
    onAction: ($event) => {
      this.editColumnsToDisplay($event);
    }
  };

  private statusFilterAction: WidgetAction = {
    name: 'alarm.alarm-status-filter',
    show: true,
    onAction: ($event) => {
      this.editAlarmStatusFilter($event);
    },
    icon: 'filter_list'
  };

  constructor(protected store: Store<AppState>,
              private elementRef: ElementRef,
              private ngZone: NgZone,
              private overlay: Overlay,
              private viewContainerRef: ViewContainerRef,
              private utils: UtilsService,
              public translate: TranslateService,
              private domSanitizer: DomSanitizer,
              private datePipe: DatePipe,
              private dialog: MatDialog,
              private dialogService: DialogService,
              private alarmService: AlarmService) {
    super(store);

    const sortOrder: SortOrder = sortOrderFromString(this.defaultSortOrder);
    this.pageLink = new PageLink(this.defaultPageSize, 0, null, sortOrder);
  }

  ngOnInit(): void {
    this.ctx.$scope.alarmsTableWidget = this;
    this.settings = this.ctx.settings;
    this.widgetConfig = this.ctx.widgetConfig;
    this.subscription = this.ctx.defaultSubscription;
    this.alarmSource = this.subscription.alarmSource;
    this.initializeConfig();
    this.updateAlarmSource();
    this.ctx.updateWidgetParams();
  }

  ngAfterViewInit(): void {
    fromEvent(this.searchInputField.nativeElement, 'keyup')
      .pipe(
        debounceTime(150),
        distinctUntilChanged(),
        tap(() => {
          if (this.displayPagination) {
            this.paginator.pageIndex = 0;
          }
          this.updateData();
        })
      )
      .subscribe();

    if (this.displayPagination) {
      this.sort.sortChange.subscribe(() => this.paginator.pageIndex = 0);
    }
    (this.displayPagination ? merge(this.sort.sortChange, this.paginator.page) : this.sort.sortChange)
      .pipe(
        tap(() => this.updateData())
      )
      .subscribe();
    this.updateData();
  }

  public onDataUpdated() {
    this.ngZone.run(() => {
      this.alarmsDatasource.updateAlarms(this.subscription.alarms);
      this.ctx.detectChanges();
    });
  }

  private initializeConfig() {
    this.ctx.widgetActions = [this.searchAction, this.statusFilterAction, this.columnDisplayAction];

    this.displayDetails = isDefined(this.settings.displayDetails) ? this.settings.displayDetails : true;
    this.allowAcknowledgment = isDefined(this.settings.allowAcknowledgment) ? this.settings.allowAcknowledgment : true;
    this.allowClear = isDefined(this.settings.allowClear) ? this.settings.allowClear : true;

    if (this.displayDetails) {
      this.actionCellDescriptors.push(
        {
          displayName: this.translate.instant('alarm.details'),
          icon: 'more_horiz',
          details: true
        } as AlarmWidgetActionDescriptor
      );
    }

    if (this.allowAcknowledgment) {
      this.actionCellDescriptors.push(
        {
          displayName: this.translate.instant('alarm.acknowledge'),
          icon: 'done',
          acknowledge: true
        } as AlarmWidgetActionDescriptor
      );
    }

    if (this.allowClear) {
      this.actionCellDescriptors.push(
        {
          displayName: this.translate.instant('alarm.clear'),
          icon: 'clear',
          clear: true
        } as AlarmWidgetActionDescriptor
      );
    }

    this.actionCellDescriptors = this.actionCellDescriptors.concat(this.ctx.actionsApi.getActionDescriptors('actionCellButton'));

    let alarmsTitle: string;

    if (this.settings.alarmsTitle && this.settings.alarmsTitle.length) {
      alarmsTitle = this.utils.customTranslation(this.settings.alarmsTitle, this.settings.alarmsTitle);
    } else {
      alarmsTitle = this.translate.instant('alarm.alarms');
    }

    this.ctx.widgetTitle = createLabelFromDatasource(this.alarmSource, alarmsTitle);

    this.enableSelection = isDefined(this.settings.enableSelection) ? this.settings.enableSelection : true;
    if (!this.allowAcknowledgment && !this.allowClear) {
      this.enableSelection = false;
    }

    this.searchAction.show = isDefined(this.settings.enableSearch) ? this.settings.enableSearch : true;
    this.displayPagination = isDefined(this.settings.displayPagination) ? this.settings.displayPagination : true;
    this.enableStickyAction = isDefined(this.settings.enableStickyAction) ? this.settings.enableStickyAction : false;
    this.columnDisplayAction.show = isDefined(this.settings.enableSelectColumnDisplay) ? this.settings.enableSelectColumnDisplay : true;
    this.statusFilterAction.show = isDefined(this.settings.enableStatusFilter) ? this.settings.enableStatusFilter : true;

    const pageSize = this.settings.defaultPageSize;
    if (isDefined(pageSize) && isNumber(pageSize) && pageSize > 0) {
      this.defaultPageSize = pageSize;
    }
    this.pageSizeOptions = [this.defaultPageSize, this.defaultPageSize * 2, this.defaultPageSize * 3];
    this.pageLink.pageSize = this.displayPagination ? this.defaultPageSize : Number.POSITIVE_INFINITY;

    const cssString = constructTableCssString(this.widgetConfig);
    const cssParser = new cssjs();
    cssParser.testMode = false;
    const namespace = 'alarms-table-' + hashCode(cssString);
    cssParser.cssPreviewNamespace = namespace;
    cssParser.createStyleElement(namespace, cssString);
    $(this.elementRef.nativeElement).addClass(namespace);
  }

  private updateAlarmSource() {

    if (this.enableSelection) {
      this.displayedColumns.push('select');
    }

    if (this.alarmSource) {
      this.alarmSource.dataKeys.forEach((alarmDataKey) => {
        const dataKey: EntityColumn = deepClone(alarmDataKey) as EntityColumn;
        dataKey.title = this.utils.customTranslation(dataKey.label, dataKey.label);
        dataKey.def = 'def' + this.columns.length;
        const keySettings: TableWidgetDataKeySettings = dataKey.settings;

        this.stylesInfo[dataKey.def] = getCellStyleInfo(keySettings);
        this.contentsInfo[dataKey.def] = getCellContentInfo(keySettings, 'value, alarm, ctx');
        this.columnWidth[dataKey.def] = getColumnWidth(keySettings);
        this.columns.push(dataKey);
      });
      this.displayedColumns.push(...this.columns.map(column => column.def));
    }
    if (this.settings.defaultSortOrder && this.settings.defaultSortOrder.length) {
      this.defaultSortOrder = this.settings.defaultSortOrder;
    }
    this.pageLink.sortOrder = sortOrderFromString(this.defaultSortOrder);
    this.sortOrderProperty = toAlarmColumnDef(this.pageLink.sortOrder.property, this.columns);

    if (this.actionCellDescriptors.length) {
      this.displayedColumns.push('actions');
    }
    this.alarmsDatasource = new AlarmsDatasource();
    if (this.enableSelection) {
      this.alarmsDatasource.selectionModeChanged$.subscribe((selectionMode) => {
        const hideTitlePanel = selectionMode || this.textSearchMode;
        if (this.ctx.hideTitlePanel !== hideTitlePanel) {
          this.ctx.hideTitlePanel = hideTitlePanel;
          this.ctx.detectChanges(true);
        } else {
          this.ctx.detectChanges();
        }
      });
    }
  }

  private editColumnsToDisplay($event: Event) {
    if ($event) {
      $event.stopPropagation();
    }
    const target = $event.target || $event.srcElement || $event.currentTarget;
    const config = new OverlayConfig();
    config.backdropClass = 'cdk-overlay-transparent-backdrop';
    config.hasBackdrop = true;
    const connectedPosition: ConnectedPosition = {
      originX: 'end',
      originY: 'bottom',
      overlayX: 'end',
      overlayY: 'top'
    };
    config.positionStrategy = this.overlay.position().flexibleConnectedTo(target as HTMLElement)
      .withPositions([connectedPosition]);

    const overlayRef = this.overlay.create(config);
    overlayRef.backdropClick().subscribe(() => {
      overlayRef.dispose();
    });

    const columns: DisplayColumn[] = this.columns.map(column => {
      return {
        title: column.title,
        def: column.def,
        display: this.displayedColumns.indexOf(column.def) > -1
      };
    });

    const injectionTokens = new WeakMap<any, any>([
      [DISPLAY_COLUMNS_PANEL_DATA, {
        columns,
        columnsUpdated: (newColumns) => {
          this.displayedColumns = newColumns.filter(column => column.display).map(column => column.def);
          if (this.enableSelection) {
            this.displayedColumns.unshift('select');
          }
          this.displayedColumns.push('actions');
        }
      } as DisplayColumnsPanelData],
      [OverlayRef, overlayRef]
    ]);
    const injector = new PortalInjector(this.viewContainerRef.injector, injectionTokens);
    overlayRef.attach(new ComponentPortal(DisplayColumnsPanelComponent,
      this.viewContainerRef, injector));
    this.ctx.detectChanges();
  }

  private editAlarmStatusFilter($event: Event) {
    if ($event) {
      $event.stopPropagation();
    }
    const target = $event.target || $event.srcElement || $event.currentTarget;
    const config = new OverlayConfig();
    config.backdropClass = 'cdk-overlay-transparent-backdrop';
    config.hasBackdrop = true;
    const connectedPosition: ConnectedPosition = {
      originX: 'end',
      originY: 'bottom',
      overlayX: 'end',
      overlayY: 'top'
    };
    config.positionStrategy = this.overlay.position().flexibleConnectedTo(target as HTMLElement)
      .withPositions([connectedPosition]);

    const overlayRef = this.overlay.create(config);
    overlayRef.backdropClick().subscribe(() => {
      overlayRef.dispose();
    });
    const injectionTokens = new WeakMap<any, any>([
      [ALARM_STATUS_FILTER_PANEL_DATA, {
        subscription: this.subscription,
      } as AlarmStatusFilterPanelData],
      [OverlayRef, overlayRef]
    ]);
    const injector = new PortalInjector(this.viewContainerRef.injector, injectionTokens);
    overlayRef.attach(new ComponentPortal(AlarmStatusFilterPanelComponent,
      this.viewContainerRef, injector));
    this.ctx.detectChanges();
  }

  private enterFilterMode() {
    this.textSearchMode = true;
    this.pageLink.textSearch = '';
    this.ctx.hideTitlePanel = true;
    this.ctx.detectChanges(true);
    setTimeout(() => {
      this.searchInputField.nativeElement.focus();
      this.searchInputField.nativeElement.setSelectionRange(0, 0);
    }, 10);
  }

  exitFilterMode() {
    this.textSearchMode = false;
    this.pageLink.textSearch = null;
    if (this.displayPagination) {
      this.paginator.pageIndex = 0;
    }
    this.updateData();
    this.ctx.hideTitlePanel = false;
    this.ctx.detectChanges(true);
  }

  private updateData() {
    if (this.displayPagination) {
      this.pageLink.page = this.paginator.pageIndex;
      this.pageLink.pageSize = this.paginator.pageSize;
    } else {
      this.pageLink.page = 0;
    }
    this.pageLink.sortOrder.property = fromAlarmColumnDef(this.sort.active, this.columns);
    this.pageLink.sortOrder.direction = Direction[this.sort.direction.toUpperCase()];
    this.alarmsDatasource.loadAlarms(this.pageLink);
    this.ctx.detectChanges();
  }

  public trackByColumnDef(index, column: EntityColumn) {
    return column.def;
  }

  public headerStyle(key: EntityColumn): any {
    const columnWidth = this.columnWidth[key.def];
    return widthStyle(columnWidth);
  }

  public cellStyle(alarm: AlarmInfo, key: EntityColumn): any {
    let style: any = {};
    if (alarm && key) {
      const styleInfo = this.stylesInfo[key.def];
      const value = getAlarmValue(alarm, key);
      if (styleInfo.useCellStyleFunction && styleInfo.cellStyleFunction) {
        try {
          style = styleInfo.cellStyleFunction(value);
        } catch (e) {
          style = {};
        }
      } else {
        style = this.defaultStyle(key, value);
      }
    }
    if (!style.width) {
      const columnWidth = this.columnWidth[key.def];
      style = {...style, ...widthStyle(columnWidth)};
    }
    return style;
  }

  public cellContent(alarm: AlarmInfo, key: EntityColumn): SafeHtml {
    if (alarm && key) {
      const contentInfo = this.contentsInfo[key.def];
      const value = getAlarmValue(alarm, key);
      let content = '';
      if (contentInfo.useCellContentFunction && contentInfo.cellContentFunction) {
        try {
          content = contentInfo.cellContentFunction(value, alarm, this.ctx);
        } catch (e) {
          content = '' + value;
        }
      } else {
        content = this.defaultContent(key, value);
      }
      return isDefined(content) ? this.domSanitizer.bypassSecurityTrustHtml(content) : '';
    } else {
      return '';
    }
  }

  public onRowClick($event: Event, alarm: AlarmInfo) {
    if ($event) {
      $event.stopPropagation();
    }
    this.alarmsDatasource.toggleCurrentAlarm(alarm);
    const descriptors = this.ctx.actionsApi.getActionDescriptors('rowClick');
    if (descriptors.length) {
      let entityId;
      let entityName;
      if (alarm && alarm.originator) {
        entityId = alarm.originator;
        entityName = alarm.originatorName;
      }
      this.ctx.actionsApi.handleWidgetAction($event, descriptors[0], entityId, entityName, {alarm});
    }
  }

  public onActionButtonClick($event: Event, alarm: AlarmInfo, actionDescriptor: AlarmWidgetActionDescriptor) {
    if (actionDescriptor.details) {
      this.openAlarmDetails($event, alarm);
    } else if (actionDescriptor.acknowledge) {
      this.ackAlarm($event, alarm);
    } else if (actionDescriptor.clear) {
      this.clearAlarm($event, alarm);
    } else {
      if ($event) {
        $event.stopPropagation();
      }
      let entityId;
      let entityName;
      if (alarm && alarm.originator) {
        entityId = alarm.originator;
        entityName = alarm.originatorName;
      }
      this.ctx.actionsApi.handleWidgetAction($event, actionDescriptor, entityId, entityName, {alarm});
    }
  }

  public actionEnabled(alarm: AlarmInfo, actionDescriptor: AlarmWidgetActionDescriptor): boolean {
    if (actionDescriptor.acknowledge) {
      return (alarm.status === AlarmStatus.ACTIVE_UNACK ||
        alarm.status === AlarmStatus.CLEARED_UNACK);
    } else if (actionDescriptor.clear) {
      return (alarm.status === AlarmStatus.ACTIVE_ACK ||
        alarm.status === AlarmStatus.ACTIVE_UNACK);
    }
    return true;
  }

  private openAlarmDetails($event: Event, alarm: AlarmInfo) {
    if ($event) {
      $event.stopPropagation();
    }
    if (alarm && alarm.id && alarm.id.id !== NULL_UUID) {
      this.dialog.open<AlarmDetailsDialogComponent, AlarmDetailsDialogData, boolean>
      (AlarmDetailsDialogComponent,
        {
          disableClose: true,
          panelClass: ['tb-dialog', 'tb-fullscreen-dialog'],
          data: {
            alarmId: alarm.id.id,
            allowAcknowledgment: this.allowAcknowledgment,
            allowClear: this.allowClear,
            displayDetails: true
          }
        }).afterClosed().subscribe(
        (res) => {
          if (res) {
            this.subscription.update();
          }
        }
      );
    }
  }

  private ackAlarm($event: Event, alarm: AlarmInfo) {
    if ($event) {
      $event.stopPropagation();
    }
    if (alarm && alarm.id && alarm.id.id !== NULL_UUID) {
      this.dialogService.confirm(
        this.translate.instant('alarm.aknowledge-alarm-title'),
        this.translate.instant('alarm.aknowledge-alarm-text'),
        this.translate.instant('action.no'),
        this.translate.instant('action.yes')
      ).subscribe((res) => {
        if (res) {
          if (res) {
            this.alarmService.ackAlarm(alarm.id.id).subscribe(() => {
              this.subscription.update();
            });
          }
        }
      });
    }
  }

  public ackAlarms($event: Event) {
    if ($event) {
      $event.stopPropagation();
    }
    if (this.alarmsDatasource.selection.hasValue()) {
      const alarms = this.alarmsDatasource.selection.selected.filter(
        (alarm) => alarm.id.id !== NULL_UUID
      );
      if (alarms.length) {
        const title = this.translate.instant('alarm.aknowledge-alarms-title', {count: alarms.length});
        const content = this.translate.instant('alarm.aknowledge-alarms-text', {count: alarms.length});
        this.dialogService.confirm(
          title,
          content,
          this.translate.instant('action.no'),
          this.translate.instant('action.yes')
        ).subscribe((res) => {
          if (res) {
            if (res) {
              const tasks: Observable<void>[] = [];
              for (const alarm of alarms) {
                tasks.push(this.alarmService.ackAlarm(alarm.id.id));
              }
              forkJoin(tasks).subscribe(() => {
                this.alarmsDatasource.clearSelection();
                this.subscription.update();
              });
            }
          }
        });
      }
    }
  }

  private clearAlarm($event: Event, alarm: AlarmInfo) {
    if ($event) {
      $event.stopPropagation();
    }
    if (alarm && alarm.id && alarm.id.id !== NULL_UUID) {
      this.dialogService.confirm(
        this.translate.instant('alarm.clear-alarm-title'),
        this.translate.instant('alarm.clear-alarm-text'),
        this.translate.instant('action.no'),
        this.translate.instant('action.yes')
      ).subscribe((res) => {
        if (res) {
          if (res) {
            this.alarmService.clearAlarm(alarm.id.id).subscribe(() => {
              this.subscription.update();
            });
          }
        }
      });
    }
  }

  public clearAlarms($event: Event) {
    if ($event) {
      $event.stopPropagation();
    }
    if (this.alarmsDatasource.selection.hasValue()) {
      const alarms = this.alarmsDatasource.selection.selected.filter(
        (alarm) => alarm.id.id !== NULL_UUID
      );
      if (alarms.length) {
        const title = this.translate.instant('alarm.clear-alarms-title', {count: alarms.length});
        const content = this.translate.instant('alarm.clear-alarms-text', {count: alarms.length});
        this.dialogService.confirm(
          title,
          content,
          this.translate.instant('action.no'),
          this.translate.instant('action.yes')
        ).subscribe((res) => {
          if (res) {
            if (res) {
              const tasks: Observable<void>[] = [];
              for (const alarm of alarms) {
                tasks.push(this.alarmService.clearAlarm(alarm.id.id));
              }
              forkJoin(tasks).subscribe(() => {
                this.alarmsDatasource.clearSelection();
                this.subscription.update();
              });
            }
          }
        });
      }
    }
  }

  private defaultContent(key: EntityColumn, value: any): any {
    if (isDefined(value)) {
      const alarmField = alarmFields[key.name];
      if (alarmField) {
        if (alarmField.time) {
          return this.datePipe.transform(value, 'yyyy-MM-dd HH:mm:ss');
        } else if (alarmField.value === alarmFields.severity.value) {
          return this.translate.instant(alarmSeverityTranslations.get(value));
        } else if (alarmField.value === alarmFields.status.value) {
          return this.translate.instant(alarmStatusTranslations.get(value));
        } else if (alarmField.value === alarmFields.originatorType.value) {
          return this.translate.instant(entityTypeTranslations.get(value).type);
        } else {
          return value;
        }
      } else {
        return value;
      }
    } else {
      return '';
    }
  }

  private defaultStyle(key: EntityColumn, value: any): any {
    if (isDefined(value)) {
      const alarmField = alarmFields[key.name];
      if (alarmField) {
        if (alarmField.value === alarmFields.severity.value) {
          return {
            fontWeight: 'bold',
            color: alarmSeverityColors.get(value)
          };
        } else {
          return {};
        }
      } else {
        return {};
      }
    } else {
      return {};
    }
  }

}

class AlarmsDatasource implements DataSource<AlarmInfo> {

  private alarmsSubject = new BehaviorSubject<AlarmInfo[]>([]);
  private pageDataSubject = new BehaviorSubject<PageData<AlarmInfo>>(emptyPageData<AlarmInfo>());

  public selection = new SelectionModel<AlarmInfo>(true, [], false);

  private selectionModeChanged = new EventEmitter<boolean>();

  public  selectionModeChanged$ = this.selectionModeChanged.asObservable();

  private allAlarms: Array<AlarmInfo> = [];
  private allAlarmsSubject = new BehaviorSubject<AlarmInfo[]>([]);
  private allAlarms$: Observable<Array<AlarmInfo>> = this.allAlarmsSubject.asObservable();

  private currentAlarm: AlarmInfo = null;

  constructor() {
  }

  connect(collectionViewer: CollectionViewer): Observable<AlarmInfo[] | ReadonlyArray<AlarmInfo>> {
    return this.alarmsSubject.asObservable();
  }

  disconnect(collectionViewer: CollectionViewer): void {
    this.alarmsSubject.complete();
    this.pageDataSubject.complete();
  }

  loadAlarms(pageLink: PageLink) {
    if (this.selection.hasValue()) {
      this.selection.clear();
      this.onSelectionModeChanged(false);
    }
    this.fetchAlarms(pageLink).pipe(
      catchError(() => of(emptyPageData<AlarmInfo>())),
    ).subscribe(
      (pageData) => {
        this.alarmsSubject.next(pageData.data);
        this.pageDataSubject.next(pageData);
      }
    );
  }

  updateAlarms(alarms: AlarmInfo[]) {
    alarms.forEach((newAlarm) => {
      const existingAlarmIndex = this.allAlarms.findIndex(alarm => alarm.id.id === newAlarm.id.id);
      if (existingAlarmIndex > -1) {
        Object.assign(this.allAlarms[existingAlarmIndex], newAlarm);
      } else {
        this.allAlarms.push(newAlarm);
      }
    });
    for (let i = this.allAlarms.length - 1; i >= 0; i--) {
      const oldAlarm = this.allAlarms[i];
      const newAlarmIndex = alarms.findIndex(alarm => alarm.id.id === oldAlarm.id.id);
      if (newAlarmIndex === -1) {
        this.allAlarms.splice(i, 1);
      }
    }
    if (this.selection.hasValue()) {
      const toRemove: AlarmInfo[] = [];
      this.selection.selected.forEach((selectedAlarm) => {
        const existingAlarm = this.allAlarms.find(alarm => alarm.id.id === selectedAlarm.id.id);
        if (!existingAlarm) {
          toRemove.push(selectedAlarm);
        }
      });
      this.selection.deselect(...toRemove);
      if (this.selection.isEmpty()) {
        this.onSelectionModeChanged(false);
      }
    }
    this.allAlarmsSubject.next(this.allAlarms);
  }

  isAllSelected(): Observable<boolean> {
    const numSelected = this.selection.selected.length;
    return this.alarmsSubject.pipe(
      map((alarms) => numSelected === alarms.length)
    );
  }

  isEmpty(): Observable<boolean> {
    return this.alarmsSubject.pipe(
      map((alarms) => !alarms.length)
    );
  }

  total(): Observable<number> {
    return this.pageDataSubject.pipe(
      map((pageData) => pageData.totalElements)
    );
  }

  toggleSelection(alarm: AlarmInfo) {
    const hasValue = this.selection.hasValue();
    this.selection.toggle(alarm);
    if (hasValue !== this.selection.hasValue()) {
      this.onSelectionModeChanged(this.selection.hasValue());
    }
  }

  isSelected(alarm: AlarmInfo): boolean {
    return this.selection.isSelected(alarm);
  }

  clearSelection() {
    if (this.selection.hasValue()) {
      this.selection.clear();
      this.onSelectionModeChanged(false);
    }
  }

  masterToggle() {
    this.alarmsSubject.pipe(
      tap((alarms) => {
        const numSelected = this.selection.selected.length;
        if (numSelected === alarms.length) {
          this.selection.clear();
          if (numSelected > 0) {
            this.onSelectionModeChanged(false);
          }
        } else {
          alarms.forEach(row => {
            this.selection.select(row);
          });
          if (numSelected === 0) {
            this.onSelectionModeChanged(true);
          }
        }
      }),
      take(1)
    ).subscribe();
  }

  public toggleCurrentAlarm(alarm: AlarmInfo): boolean {
    if (this.currentAlarm !== alarm) {
      this.currentAlarm = alarm;
      return true;
    } else {
      return false;
    }
  }

  public isCurrentAlarm(alarm: AlarmInfo): boolean {
    return (this.currentAlarm && alarm && this.currentAlarm.id && alarm.id) &&
      (this.currentAlarm.id.id === alarm.id.id);
  }

  private onSelectionModeChanged(selectionMode: boolean) {
    this.selectionModeChanged.emit(selectionMode);
  }

  private fetchAlarms(pageLink: PageLink): Observable<PageData<AlarmInfo>> {
    return this.allAlarms$.pipe(
      map((data) => pageLink.filterData(data))
    );
  }
}