wongjiahau/ttap-web

import Combinatorics from "js-combinatorics";
import { ObjectStore } from "../dataStructure/objectStore";
import { RawSlot } from "../model/rawSlot";
import { Subject } from "../model/subject";
import { ParseRawSlotToSlot } from "../parser/parseRawSlotToSlot";
import { ParseSlotToTinySlot } from "../parser/parseSlotToTinySlot";
import { FindTimetable } from "../permutator/findTimetable";

/**
 * This function is impure, it will modify the input.
 * @export
 * @param {Subject[]} subjects,
 * Each subject object will be modified after this function.
 */
export function FindClashes(
  subjects: Subject[],
  rawSlotStore: ObjectStore<RawSlot>
): void {
  if (subjects.length < 2) {
    throw new Error(
      "How is it possible to have clashes if there are only one subject selected?"
    );
  }
  const combinations = Combinatorics.combination(subjects, 2).toArray();
  for (let i = 0; i < combinations.length; i++) {
    const subject1 = combinations[i][0];
    const subject2 = combinations[i][1];
    if (subject1.ClashingCounterparts.some((code) => code === subject2.Code)) {
      continue;
    }
    const slotUids = [subject1, subject2].flatMap((x) => x.SlotUids);
    const slots = rawSlotStore.GetBunch(slotUids);
    const timetables = FindTimetable(
      ParseSlotToTinySlot(ParseRawSlotToSlot(slots))
    );
    if (timetables.length === 0) {
      subject1.ClashingCounterparts.push(subject2.Code);
      subject2.ClashingCounterparts.push(subject1.Code);
    }
  }
}