import { Quad, Store } from "n3";
import { Stream } from "rdf-js";

export class Patch {
  delQuads: Quad[] = [];
  addQuads: Quad[] = [];
  toString(): string {
    return `Patch -${this.delQuads.length} +${this.addQuads.length}`;
  }
  constructor() { }

  // fill `addQuads` with this stream
  public async streamImport(quadStream: Stream): Promise<void> {
    return new Promise((resolve, reject) => {
      quadStream.on("data", (quad) => {
        this.addQuads.push(quad);
      });
      quadStream.on("error", reject);
      quadStream.on("end", resolve);
    });
  }

  public applyToStore(s: Store) {
    s.removeQuads(this.delQuads);
    s.addQuads(this.addQuads);
  }
}