Get destination match in algorithms

app/core/tournament/algorithms.test.ts

@@ -6,10 +6,12 @@ import {
   Match,
   TeamIdentifier,
 } from "./algorithms";
+import { countRounds } from "./bracket";
 
 const AmountOfTeams = suite("Amount of teams");
 const Byes = suite("Byes");
 const Seeds = suite("Seeds");
+const BracketPaths = suite("Bracket path");
 const FillParticipantsWithNull = suite(
   "fillParticipantsWithNullTillPowerOfTwo()"
 );
@@ -81,6 +83,52 @@ Seeds("First and second seed are spread apart", () => {
   );
 });
 
+BracketPaths("Following winners", () => {
+  const bracket16 = eliminationBracket(16, "DE");
+  const count = countRounds(bracket16);
+
+  let latest: Match = bracket16.winners[0];
+  let rounds = 0;
+  let roundIds = new Set();
+  while (latest) {
+    rounds++;
+    roundIds.add(latest.id);
+    if (!latest.winnerDestinationMatch) {
+      break;
+    }
+    assert.equal(latest.side, "winners");
+    assert.ok(latest.loserDestinationMatch);
+    latest = latest.winnerDestinationMatch;
+  }
+
+  // no duplicate rounds
+  assert.equal(roundIds.size, rounds);
+
+  assert.equal(rounds, count.winners);
+});
+
+BracketPaths("Following losers", () => {
+  const bracket16 = eliminationBracket(16, "DE");
+  const count = countRounds(bracket16);
+
+  let latest: Match = bracket16.winners[0];
+  let rounds = 0;
+  let roundIds = new Set();
+  while (latest) {
+    rounds++;
+    roundIds.add(latest.id);
+    if (!latest.winnerDestinationMatch && !latest.loserDestinationMatch) {
+      break;
+    }
+    latest = (latest.loserDestinationMatch ?? latest.winnerDestinationMatch)!;
+  }
+
+  // no duplicate rounds
+  assert.equal(roundIds.size, rounds);
+
+  assert.equal(rounds, count.losers + 3); // 3 rounds of winners: first round, grand finals & bracket reset
+});
+
 FillParticipantsWithNull("17", () => {
   const participants: TeamIdentifier[] = new Array(17)
     .fill(null)
@@ -120,4 +168,5 @@ function teamWithBye(matches: Match[]) {
 AmountOfTeams.run();
 Byes.run();
 Seeds.run();
+BracketPaths.run();
 FillParticipantsWithNull.run();

app/core/tournament/algorithms.ts

@@ -1,5 +1,6 @@
 import invariant from "tiny-invariant";
 import { v4 as uuidv4 } from "uuid";
+import type { EliminationBracketSide } from "./bracket";
 
 /** Singe/Double Elimination bracket algorithm that handles byes
  * @link https://stackoverflow.com/a/59615574 */
@@ -57,6 +58,7 @@ export function eliminationBracket(
     const firstRoundMatch = createMatch({
       upperTeam,
       lowerTeam,
+      side: "winners",
     });
 
     matchesWQueue.push(firstRoundMatch);
@@ -74,8 +76,12 @@ export function eliminationBracket(
     const winnersBracketMatch = createMatch({
       match1,
       match2,
+      side: "winners",
     });
 
+    match1.winnerDestinationMatch = winnersBracketMatch;
+    match2.winnerDestinationMatch = winnersBracketMatch;
+
     matchesWQueue.push(winnersBracketMatch);
     bracket.winners.push(winnersBracketMatch);
     // add match to backfill for Lower Queue
@@ -121,8 +127,20 @@ export function eliminationBracket(
     const losersMatch = createMatch({
       match1,
       match2,
+      side: "losers",
     });
 
+    match1[
+      match1.side === "winners"
+        ? "loserDestinationMatch"
+        : "winnerDestinationMatch"
+    ] = losersMatch;
+    match2[
+      match2.side === "winners"
+        ? "loserDestinationMatch"
+        : "winnerDestinationMatch"
+    ] = losersMatch;
+
     matchesLQueue.push(losersMatch);
     bracket.losers.push(losersMatch);
   }
@@ -137,13 +155,23 @@ export function eliminationBracket(
   const grandFinals = createMatch({
     match1,
     match2,
+    side: "winners",
   });
+
+  match1.winnerDestinationMatch = grandFinals;
+  match2.winnerDestinationMatch = grandFinals;
+
   bracket.winners.push(grandFinals);
 
   const bracketReset = createMatch({
     match1: grandFinals,
     match2: grandFinals,
+    side: "winners",
   });
+
+  grandFinals.winnerDestinationMatch = bracketReset;
+  grandFinals.loserDestinationMatch = bracketReset;
+
   bracket.winners.push(bracketReset);
 
   return bracket;
@@ -212,6 +240,9 @@ export interface Match {
   match1?: Match;
   /** Match that leads to this match */
   match2?: Match;
+  loserDestinationMatch?: Match;
+  winnerDestinationMatch?: Match;
+  side: EliminationBracketSide;
 }
 
 export interface Bracket {