import { NamedNode } from "n3";
import { SubEvent } from "sub-events";
import { MultiStore } from "./MultiStore";
import { SourceGraph } from "./SourceGraph";
import { ViewConfig } from "./layout/ViewConfig";

// Connect <streamed-graph>, <sg-source>, <sg-view>, MultiStore, and ViewConfig.
// Makes the (single) MultiStore and the (updated as needed) ViewConfig.

// This is poorly named since it deals in both the <sg-source> elements that you
// "configured" plus the set of SourceGraph objs that are actually connected to remote graphs.

// sic private- this is just for documenting the interface more clearly
interface IConfiguredSources {
  // outputs
  graph: MultiStore; // const- only the graph contents will change
  viewConfig: ViewConfig;

  // methods
  newSourceGraph: (s: SourceGraph) => void;
  lostSourceGraph: (s: SourceGraph) => void;
  viewUriChanged: (v: NamedNode) => void;

  // events
  viewConfigChanged: SubEvent<ViewConfig>;
}

export class ConfiguredSources implements IConfiguredSources {
  graph: MultiStore;
  viewConfig: ViewConfig;

  viewConfigChanged: SubEvent<ViewConfig> = new SubEvent();

  private viewUri: NamedNode = new NamedNode("empty-view-config");

  constructor() {
    this.graph = new MultiStore();
    this.graph.graphChanged.subscribe(() => this.viewConfigMaybeChanged());
    this.viewConfig = new ViewConfig(this.graph, this.viewUri);
  }

  private viewConfigMaybeChanged() {
    this.viewConfig = new ViewConfig(this.graph, this.viewUri);
    this.viewConfigChanged.emit(this.viewConfig);
  }

  newSourceGraph(s: SourceGraph) {
    this.graph.newStore(s);
    this.viewConfigMaybeChanged();
  }
  
  lostSourceGraph(s: SourceGraph) {
    throw new Error("notimplemented");
    this.viewConfigMaybeChanged();
  }
  
  viewUriChanged(v: NamedNode) {
    if (v && v == this.viewUri) {
      return;
    }
    this.viewUri = v;
    this.viewConfigMaybeChanged();
  }
}