import * as vscode from 'vscode';
import { MultiStreamService } from './multiStreamService';
import { StreamListItem } from './streamListItem';

export class StreamListDataProvider implements vscode.TreeDataProvider<StreamListItem> {
  private _onDidChangeTreeData = new vscode.EventEmitter<StreamListItem | undefined | null | void>();
  readonly onDidChangeTreeData = this._onDidChangeTreeData.event;
  private currentItems: StreamListItem[] = [];

  constructor(private multiStreamService: MultiStreamService) {
    multiStreamService.onDidChangeStreams(() => {
      this.refresh();
    });
    // multiStreamService.onDidChangeLog(() => {
    //   this.refresh();
    // });
    multiStreamService.onDidChangeActiveStream(() => {
      this.refresh();
    });
  }

  refresh(): void {
    this._onDidChangeTreeData.fire();
  }

  getTreeItem(element: StreamListItem): vscode.TreeItem {
    return element;
  }

  getParent(element: StreamListItem): vscode.ProviderResult<StreamListItem> {
    return null;
  }

  getChildren(element?: StreamListItem): Thenable<StreamListItem[]> {
    if (element) {
      return Promise.resolve([]);
    }

    const streams = this.multiStreamService.getStreams();
    const activeStreamId = this.multiStreamService.getActiveStreamId();

    const items = streams.map(stream => {
      const logs = this.multiStreamService.getLogsByStream(stream.id);
      const isActive = stream.id === activeStreamId;
      return new StreamListItem(stream, logs.length, isActive);
    });

    this.currentItems = items;
    return Promise.resolve(items);
  }

  getActiveItem(): StreamListItem | undefined {
    const activeStreamId = this.multiStreamService.getActiveStreamId();
    return this.currentItems.find(item => item.streamId === activeStreamId);
  }
}