Re-resolve both Elimination Final slots on every Wildcard result

Now that a Wildcard winner's destination depends on both games, guarding
only the slot about to be written is not enough. Correcting a recorded
result placed the new winner in the other Elimination Final and left the
beaten team alive in the one it had been written to, and a bracket already
advanced under the old fixed crossover ended up with one team in both
Elimination Finals once the second result came in — the second write hit
"already filled", which every caller swallows.

Each result now reconciles both slots against the resolved pairings:
a Wildcard team sitting in the wrong slot is vacated, the right ones are
written, and a slot held by anyone outside the Wildcard Round still raises
"already filled" rather than being taken. Clearing and filling share one
transaction, so a half-applied re-seed cannot leave a team in both games,
and pairings that are already correct do no writes at all.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VDbHrCce1UhahbkwKkc7hK

app/lib/__tests__/afl-wildcard-reseed.test.ts

@@ -0,0 +1,117 @@
+/**
+ * The AFL Wildcard winners are re-seeded into the Elimination Finals by ladder position
+ * (5th draws the lower-ranked winner, 6th the higher-ranked one) rather than crossing
+ * over from a fixed Wildcard match. These tests pin that mapping for every combination
+ * of results, and for either order of entry.
+ */
+
+import { describe, it, expect } from "vitest";
+import {
+  resolveAflWildcardPlacements,
+  AFL_WILDCARD_DRAW,
+  AFL_ELIMINATION_HOSTS,
+  type AflWildcardResult,
+} from "../afl-wildcard-reseed";
+
+/** Both Wildcard games decided, addressed by the seed that won each. */
+function bothDecided(match1Winner: 7 | 10, match2Winner: 8 | 9): AflWildcardResult[] {
+  return [
+    { matchNumber: 1, winnerSlot: match1Winner === 7 ? 1 : 2 },
+    { matchNumber: 2, winnerSlot: match2Winner === 8 ? 1 : 2 },
+  ];
+}
+
+/** Elimination Finals match number each winning seed was sent to. */
+function slotsBySeed(results: AflWildcardResult[]): Record<number, number> {
+  return Object.fromEntries(
+    resolveAflWildcardPlacements(results).map((p) => [p.seed, p.eliminationMatchNumber])
+  );
+}
+
+describe("AFL Wildcard draw constants", () => {
+  it("draws 7v10 and 8v9", () => {
+    expect(AFL_WILDCARD_DRAW[1]).toEqual([7, 10]);
+    expect(AFL_WILDCARD_DRAW[2]).toEqual([8, 9]);
+  });
+
+  it("hosts the Elimination Finals with seeds 5 and 6", () => {
+    expect(AFL_ELIMINATION_HOSTS[1]).toBe(5);
+    expect(AFL_ELIMINATION_HOSTS[2]).toBe(6);
+  });
+});
+
+describe("resolveAflWildcardPlacements", () => {
+  it("sends the higher-ranked winner to 6th and the lower to 5th (7 and 8 win)", () => {
+    expect(slotsBySeed(bothDecided(7, 8))).toEqual({ 7: 2, 8: 1 });
+  });
+
+  it("re-seeds when the lower seed wins the 7v10 game (10 and 8 win)", () => {
+    // The bug this replaces sent the 7v10 winner to 6th regardless, pairing 5th with
+    // 8th and handing 6th the weakest survivor.
+    expect(slotsBySeed(bothDecided(10, 8))).toEqual({ 8: 2, 10: 1 });
+  });
+
+  it("re-seeds when the lower seed wins the 8v9 game (7 and 9 win)", () => {
+    expect(slotsBySeed(bothDecided(7, 9))).toEqual({ 7: 2, 9: 1 });
+  });
+
+  it("re-seeds when both lower seeds win (10 and 9 win)", () => {
+    expect(slotsBySeed(bothDecided(10, 9))).toEqual({ 9: 2, 10: 1 });
+  });
+
+  it("places the 7v10 winner alone, since its rank is settled either way", () => {
+    // 7th outranks both possible 8v9 winners; 10th is outranked by both.
+    expect(slotsBySeed([
+      { matchNumber: 1, winnerSlot: 1 },
+      { matchNumber: 2, winnerSlot: null },
+    ])).toEqual({ 7: 2 });
+
+    expect(slotsBySeed([
+      { matchNumber: 1, winnerSlot: 2 },
+      { matchNumber: 2, winnerSlot: null },
+    ])).toEqual({ 10: 1 });
+  });
+
+  it("holds an 8v9 winner back until the 7v10 game is decided", () => {
+    // 8th and 9th both sit between 7th and 10th, so either slot is still possible.
+    expect(slotsBySeed([
+      { matchNumber: 1, winnerSlot: null },
+      { matchNumber: 2, winnerSlot: 1 },
+    ])).toEqual({});
+
+    expect(slotsBySeed([
+      { matchNumber: 1, winnerSlot: null },
+      { matchNumber: 2, winnerSlot: 2 },
+    ])).toEqual({});
+  });
+
+  it("places nothing while both games are undecided", () => {
+    expect(resolveAflWildcardPlacements([
+      { matchNumber: 1, winnerSlot: null },
+      { matchNumber: 2, winnerSlot: null },
+    ])).toEqual([]);
+  });
+
+  it("gives the same answer whichever result is entered first", () => {
+    for (const m1 of [7, 10] as const) {
+      for (const m2 of [8, 9] as const) {
+        const final = slotsBySeed(bothDecided(m1, m2));
+
+        // Whatever a single result places must survive the second result unchanged.
+        const m1First = slotsBySeed([
+          { matchNumber: 1, winnerSlot: m1 === 7 ? 1 : 2 },
+          { matchNumber: 2, winnerSlot: null },
+        ]);
+        for (const [seed, slot] of Object.entries(m1First)) {
+          expect(final[Number(seed)]).toBe(slot);
+        }
+      }
+    }
+  });
+
+  it("rejects a match number outside the Wildcard draw", () => {
+    expect(() => resolveAflWildcardPlacements([{ matchNumber: 3, winnerSlot: 1 }])).toThrow(
+      /Unknown AFL Wildcard Round match number 3/
+    );
+  });
+});

app/lib/afl-wildcard-reseed.ts

@@ -0,0 +1,99 @@
+/**
+ * AFL Wildcard Round → Elimination Finals re-seeding.
+ *
+ * The Wildcard Round is drawn 7 v 10 and 8 v 9, and its two winners fill the open slots
+ * in the Elimination Finals opposite the 5th and 6th seeds. Those slots are NOT a fixed
+ * crossover: the winners are re-seeded by ladder position, exactly as the classic final
+ * eight pairs 5 v 8 and 6 v 7 — the higher seed of the two hosts meets the lower-ranked
+ * winner. So 5th plays whichever winner finished further down the ladder and 6th plays
+ * the other, whichever Wildcard game each came out of.
+ *
+ * Worked example: 10th beats 7th and 9th beats 8th. A fixed crossover would send the
+ * 7v10 winner (10th) to 6th and the 8v9 winner (9th) to 5th — handing the higher host
+ * the better opponent. Re-seeded, 5th plays 10th and 6th plays 9th.
+ */
+
+/** Seeds drawn into each Wildcard Round match, in [participant1, participant2] order. */
+export const AFL_WILDCARD_DRAW: Readonly<Record<number, readonly [number, number]>> = {
+  1: [7, 10],
+  2: [8, 9],
+};
+
+/** Seed hosting each Elimination Finals match (its participant1 slot). */
+export const AFL_ELIMINATION_HOSTS: Readonly<Record<number, number>> = {
+  1: 5,
+  2: 6,
+};
+
+export interface AflWildcardResult {
+  matchNumber: number;
+  /** Slot the winner occupied, or null while the match is still to be played. */
+  winnerSlot: 1 | 2 | null;
+}
+
+export interface AflWildcardPlacement {
+  wildcardMatchNumber: number;
+  /** Seed of the Wildcard winner being placed. */
+  seed: number;
+  eliminationMatchNumber: number;
+}
+
+/**
+ * Decide which Elimination Final each decided Wildcard winner belongs in.
+ *
+ * A winner is only placed once its destination is settled whichever way the other
+ * Wildcard game falls, so results can be entered in either order:
+ *   - 7th winning match 1 outranks both possible match 2 winners → always meets 6th.
+ *   - 10th winning match 1 is outranked by both → always meets 5th.
+ *   - A match 2 winner (8th or 9th) sits between them, so it is held back until match 1
+ *     is decided rather than being placed and then moved.
+ *
+ * Undecided winners are simply omitted; the caller fills the slots it is handed and
+ * leaves the rest TBD.
+ */
+export function resolveAflWildcardPlacements(
+  results: readonly AflWildcardResult[]
+): AflWildcardPlacement[] {
+  const entries = results.map((result) => {
+    const draw = AFL_WILDCARD_DRAW[result.matchNumber];
+    if (!draw) {
+      throw new Error(`Unknown AFL Wildcard Round match number ${result.matchNumber}`);
+    }
+    return {
+      matchNumber: result.matchNumber,
+      seed: result.winnerSlot === null ? null : draw[result.winnerSlot - 1],
+      // Every seed the match could still send through — one entry once it is decided.
+      possibleSeeds: result.winnerSlot === null ? [...draw] : [draw[result.winnerSlot - 1]],
+    };
+  });
+
+  // Best-ranked winner takes the weakest host, so order the hosts worst seed first.
+  const hostsWorstFirst = Object.keys(AFL_ELIMINATION_HOSTS)
+    .map(Number)
+    .toSorted((a, b) => AFL_ELIMINATION_HOSTS[b] - AFL_ELIMINATION_HOSTS[a]);
+
+  const placements: AflWildcardPlacement[] = [];
+
+  for (const entry of entries) {
+    const seed = entry.seed;
+    if (seed === null) continue;
+
+    const others = entries.filter((other) => other !== entry);
+    const outranks = (other: (typeof entries)[number]) => other.possibleSeeds.every((s) => s < seed);
+    const outrankedBy = (other: (typeof entries)[number]) => other.possibleSeeds.every((s) => s > seed);
+
+    // This winner's rank is only knowable while every other one sits wholly above or
+    // wholly below it — an undecided game straddling this seed leaves it unplaceable.
+    if (!others.every((other) => outranks(other) || outrankedBy(other))) continue;
+
+    const rank = others.filter(outranks).length;
+    const eliminationMatchNumber = hostsWorstFirst[rank];
+    if (eliminationMatchNumber === undefined) {
+      throw new Error(`No Elimination Finals slot for AFL Wildcard winner ranked ${rank + 1}`);
+    }
+
+    placements.push({ wildcardMatchNumber: entry.matchNumber, seed, eliminationMatchNumber });
+  }
+
+  return placements;
+}

app/lib/bracket-templates.ts

@@ -703,7 +703,8 @@ export const NFL_14: BracketTemplate = {
  * - Wildcard Round: 7v10, 8v9 (losers eliminated with 0 points)
  * - Week 1 Finals:
  *   - Qualifying Finals: 1v4, 2v3 (losers get second chance)
- *   - Elimination Finals: 5v8(wildcard winner), 6v7(wildcard winner) (losers share 7th-8th)
+ *   - Elimination Finals: the two Wildcard winners are re-seeded by ladder position, so
+ *     5th hosts the lower-ranked winner and 6th the higher-ranked one (losers share 7th-8th)
  * - Week 2: Semi-Finals (QF losers vs EF winners, losers share 5th-6th)
  * - Week 3: Preliminary Finals (QF winners vs SF winners, losers share 3rd-4th)
  * - Week 4: Grand Final (1st vs 2nd)

app/models/__tests__/afl-wildcard-advancement.test.ts

@@ -0,0 +1,229 @@
+/**
+ * Advancing an AFL Wildcard Round winner into the Elimination Finals.
+ *
+ * The two winners are re-seeded by ladder position — 5th hosts the lower-ranked winner,
+ * 6th the higher-ranked one — so the destination is not a fixed crossover from a given
+ * Wildcard match, and results can be recorded in either order.
+ */
+
+import { describe, it, expect, vi, beforeEach } from "vitest";
+import { AFL_10 } from "~/lib/bracket-templates";
+
+interface MatchRow {
+  id: string;
+  scoringEventId: string;
+  round: string;
+  matchNumber: number;
+  participant1Id: string | null;
+  participant2Id: string | null;
+  isComplete: boolean;
+  winnerId: string | null;
+  loserId: string | null;
+}
+
+let rows: MatchRow[] = [];
+
+/**
+ * The literal values drizzle put in a where clause (`eq(col, value)`), which is all this
+ * mock needs to tell one lookup from another — there is no query engine behind it.
+ */
+function whereValues(node: unknown, depth = 0): string[] {
+  if (!node || depth > 10) return [];
+  if (Array.isArray(node)) return node.flatMap((child) => whereValues(child, depth + 1));
+  if (typeof node !== "object") return [];
+  const obj = node as Record<string, unknown>;
+  const own = typeof obj.value === "string" ? [obj.value] : [];
+  return [...own, ...whereValues(obj.queryChunks, depth + 1)];
+}
+
+const db = {
+  query: {
+    playoffMatches: {
+      findFirst: vi.fn(({ where }: { where: unknown }) => {
+        const values = whereValues(where);
+        return Promise.resolve(rows.find((r) => values.includes(r.id)));
+      }),
+      findMany: vi.fn(({ where }: { where: unknown }) => {
+        const values = whereValues(where);
+        return Promise.resolve(
+          rows
+            .filter((r) => values.includes(r.scoringEventId) && values.includes(r.round))
+            .toSorted((a, b) => a.matchNumber - b.matchNumber)
+        );
+      }),
+    },
+  },
+  update: vi.fn(() => ({
+    set: (data: Partial<MatchRow>) => {
+      const applyTo = (where: unknown) => {
+        const values = whereValues(where);
+        const row = rows.find((r) => values.includes(r.id));
+        if (row) Object.assign(row, data);
+        return row;
+      };
+      // Advancement writes through the query builder with and without .returning().
+      return {
+        where: (where: unknown) => {
+          const applied = Promise.resolve([applyTo(where)]);
+          return Object.assign(applied, { returning: () => applied });
+        },
+      };
+    },
+  })),
+  // No rollback: the tests assert the writes that were attempted, in order.
+  transaction: vi.fn((fn: (tx: typeof db) => Promise<unknown>) => fn(db)),
+};
+
+vi.mock("~/database/context", () => ({ database: () => db }));
+
+const { advanceWinnerTemplate } = await import("../playoff-match");
+
+const EVENT = "event-1";
+
+/** Ladder seed n → participant id. */
+const seed = (n: number) => `seed-${n}`;
+
+/** A freshly generated afl_10 Wildcard Round (7v10, 8v9) and Elimination Finals (5, 6). */
+function bracket(): MatchRow[] {
+  const base = { scoringEventId: EVENT, isComplete: false, winnerId: null, loserId: null };
+  return [
+    { ...base, id: "wc1", round: "Wildcard Round", matchNumber: 1, participant1Id: seed(7), participant2Id: seed(10) },
+    { ...base, id: "wc2", round: "Wildcard Round", matchNumber: 2, participant1Id: seed(8), participant2Id: seed(9) },
+    { ...base, id: "ef1", round: "Elimination Finals", matchNumber: 1, participant1Id: seed(5), participant2Id: null },
+    { ...base, id: "ef2", round: "Elimination Finals", matchNumber: 2, participant1Id: seed(6), participant2Id: null },
+  ];
+}
+
+function row(id: string): MatchRow {
+  const found = rows.find((r) => r.id === id);
+  if (!found) throw new Error(`No such match ${id}`);
+  return found;
+}
+
+/** Record a Wildcard result the way setMatchWinner does, then advance it. */
+async function winWildcard(id: string, winnerId: string) {
+  const match = row(id);
+  match.winnerId = winnerId;
+  match.loserId = match.participant1Id === winnerId ? match.participant2Id : match.participant1Id;
+  match.isComplete = true;
+  await advanceWinnerTemplate(id, winnerId, AFL_10);
+}
+
+describe("AFL Wildcard Round advancement", () => {
+  beforeEach(() => {
+    rows = bracket();
+  });
+
+  it("sends 5th the lower-ranked winner and 6th the higher-ranked one", async () => {
+    await winWildcard("wc1", seed(7));
+    await winWildcard("wc2", seed(8));
+
+    expect(row("ef1").participant2Id).toBe(seed(8));
+    expect(row("ef2").participant2Id).toBe(seed(7));
+  });
+
+  it("re-seeds when the lower seed wins through", async () => {
+    // The reported bug: 10th beating 7th used to be crossed straight to 6th, leaving
+    // 5th with the better survivor.
+    await winWildcard("wc1", seed(10));
+    await winWildcard("wc2", seed(8));
+
+    expect(row("ef1").participant2Id).toBe(seed(10));
+    expect(row("ef2").participant2Id).toBe(seed(8));
+  });
+
+  it("re-seeds a 9th-placed winner above a 10th-placed one", async () => {
+    await winWildcard("wc1", seed(10));
+    await winWildcard("wc2", seed(9));
+
+    expect(row("ef1").participant2Id).toBe(seed(10));
+    expect(row("ef2").participant2Id).toBe(seed(9));
+  });
+
+  it("places the same pairings whichever result is entered first", async () => {
+    await winWildcard("wc2", seed(8));
+    await winWildcard("wc1", seed(10));
+
+    expect(row("ef1").participant2Id).toBe(seed(10));
+    expect(row("ef2").participant2Id).toBe(seed(8));
+  });
+
+  it("places the 7v10 winner immediately, since its slot is settled either way", async () => {
+    await winWildcard("wc1", seed(7));
+
+    expect(row("ef2").participant2Id).toBe(seed(7));
+    expect(row("ef1").participant2Id).toBeNull();
+  });
+
+  it("holds an 8v9 winner back until the 7v10 game is decided", async () => {
+    // 8th and 9th sit between 7th and 10th, so placing one now could need undoing.
+    await winWildcard("wc2", seed(8));
+
+    expect(row("ef1").participant2Id).toBeNull();
+    expect(row("ef2").participant2Id).toBeNull();
+  });
+
+  it("does not disturb a winner it already placed", async () => {
+    await winWildcard("wc1", seed(7));
+    await winWildcard("wc2", seed(9));
+
+    expect(row("ef2").participant2Id).toBe(seed(7));
+    expect(row("ef1").participant2Id).toBe(seed(9));
+  });
+
+  it("refuses to overwrite a slot already holding someone else", async () => {
+    row("ef1").participant2Id = "stranger";
+
+    await expect(winWildcard("wc1", seed(10))).rejects.toThrow(/already filled/);
+    expect(row("ef1").participant2Id).toBe("stranger");
+  });
+
+  it("moves the winner when a recorded Wildcard result is corrected", async () => {
+    await winWildcard("wc1", seed(7));
+    expect(row("ef2").participant2Id).toBe(seed(7));
+
+    // The result was wrong: 10th won. 7th must not be left alive in the other slot.
+    await winWildcard("wc1", seed(10));
+
+    expect(row("ef1").participant2Id).toBe(seed(10));
+    expect(row("ef2").participant2Id).toBeNull();
+  });
+
+  it("re-seeds a pairing left behind by the old fixed crossover", async () => {
+    // Pre-fix state: the 7v10 winner was crossed to 6th whatever its ladder position.
+    row("wc1").winnerId = seed(10);
+    row("wc1").loserId = seed(7);
+    row("wc1").isComplete = true;
+    row("ef2").participant2Id = seed(10);
+
+    await winWildcard("wc2", seed(8));
+
+    expect(row("ef1").participant2Id).toBe(seed(10));
+    expect(row("ef2").participant2Id).toBe(seed(8));
+  });
+
+  it("swaps both winners when re-resolving an already-placed pair", async () => {
+    row("wc1").winnerId = seed(10);
+    row("wc1").loserId = seed(7);
+    row("wc1").isComplete = true;
+    row("ef2").participant2Id = seed(10);
+    row("ef1").participant2Id = seed(8);
+
+    await winWildcard("wc2", seed(8));
+
+    expect(row("ef1").participant2Id).toBe(seed(10));
+    expect(row("ef2").participant2Id).toBe(seed(8));
+  });
+
+  it("leaves the bracket alone when the pairings are already right", async () => {
+    await winWildcard("wc1", seed(7));
+    await winWildcard("wc2", seed(8));
+    db.transaction.mockClear();
+
+    await winWildcard("wc2", seed(8));
+
+    expect(db.transaction).not.toHaveBeenCalled();
+    expect(row("ef1").participant2Id).toBe(seed(8));
+    expect(row("ef2").participant2Id).toBe(seed(7));
+  });
+});

app/models/playoff-match.ts

@@ -15,6 +15,10 @@ import {
   resolveLLWSAdvancement,
   type LLWSResolvedDestination,
 } from "~/lib/llws-bracket";
+import {
+  resolveAflWildcardPlacements,
+  type AflWildcardResult,
+} from "~/lib/afl-wildcard-reseed";
 
 export type PlayoffMatch = typeof schema.playoffMatches.$inferSelect;
 export type NewPlayoffMatch = typeof schema.playoffMatches.$inferInsert;
@@ -742,7 +746,8 @@ async function generateNFL14Bracket(
  * Structure:
  * - Wildcard Round: 7v10, 8v9
  * - Qualifying Finals: 1v4, 2v3 (winners get bye to Preliminary Finals, losers to Semi-Finals)
- * - Elimination Finals: 5v8, 6v7 (where 7 and 8 are wildcard winners)
+ * - Elimination Finals: 5 and 6 host the two Wildcard winners, re-seeded by ladder
+ *   position — 5th draws the lower-ranked winner, 6th the higher-ranked one
  * - Semi-Finals: QF losers vs EF winners
  * - Preliminary Finals: QF winners vs SF winners
  * - Grand Final: PF winners
@@ -796,14 +801,16 @@ async function generateAFL10Bracket(
     });
   }
 
-  // Elimination Finals: 5th vs TBD (wildcard winner), 6th vs TBD (wildcard winner)
+  // Elimination Finals: 5th and 6th host the two Wildcard winners. Which winner lands
+  // where is decided by ladder position once both games are played (see
+  // resolveAflWildcardPlacements), not by a fixed crossover from a Wildcard match.
   const eliminationSeeding = [
-    { higher: 4, wildcard: 2 },  // #5 (index 4) vs Wildcard Match 2 winner
+    { higher: 4, opponent: "lower-ranked WC winner" },  // #5 (index 4)
-    { higher: 5, wildcard: 1 },  // #6 (index 5) vs Wildcard Match 1 winner
+    { higher: 5, opponent: "higher-ranked WC winner" }, // #6 (index 5)
   ];
 
   for (let i = 0; i < eliminationSeeding.length; i++) {
-    const { higher, wildcard } = eliminationSeeding[i];
+    const { higher, opponent } = eliminationSeeding[i];
     matches.push({
       scoringEventId: eventId,
       round: "Elimination Finals",
@@ -813,7 +820,7 @@ async function generateAFL10Bracket(
       isComplete: false,
       isScoring: true, // Losers share 7th-8th
       templateRound: "Elimination Finals",
-      seedInfo: participantIds ? `${higher + 1} vs WC${wildcard}` : null,
+      seedInfo: participantIds ? `${higher + 1} vs ${opponent}` : null,
     });
   }
 
@@ -868,7 +875,7 @@ async function generateAFL10Bracket(
  * Phase 3.3: Handles both winners and losers advancing to different rounds
  *
  * Advancement rules:
- * - Wildcard Round: Winner → Elimination Finals
+ * - Wildcard Round: Winner → Elimination Finals (re-seeded by ladder position)
  * - Qualifying Finals: Winner → Preliminary Finals, Loser → Semi-Finals
  * - Elimination Finals: Winner → Semi-Finals
  * - Semi-Finals: Winner → Preliminary Finals
@@ -881,18 +888,86 @@ async function advanceAFLWinner(
 ): Promise<void> {
   const eventId = match.scoringEventId;
 
-  // Wildcard Round: Winner advances to Elimination Finals
+  // Wildcard Round: Winners are re-seeded into the Elimination Finals — 5th meets the
+  // lower-ranked winner and 6th the higher-ranked one, not a fixed 7v10-to-6th crossover.
+  // Because the destination depends on both games, every result re-resolves both slots:
+  // that places a winner whose slot only became certain once the other game was decided,
+  // and it moves one that an earlier (or corrected) result had put in the other slot.
   if (match.round === "Wildcard Round") {
-    // Wildcard Match 1 winner → EF Match 2, participant2Id
+    const [wcMatches, efMatches] = await Promise.all([
-    // Wildcard Match 2 winner → EF Match 1, participant2Id
+      findPlayoffMatchesByEventIdAndRound(eventId, "Wildcard Round"),
-    const efMatchNumber = match.matchNumber === 1 ? 2 : 1;
+      findPlayoffMatchesByEventIdAndRound(eventId, "Elimination Finals"),
-    const efMatches = await findPlayoffMatchesByEventIdAndRound(eventId, "Elimination Finals");
+    ]);
-    const efMatch = efMatches.find((m) => m.matchNumber === efMatchNumber);
 
-    if (!efMatch) throw new Error(`Elimination Finals match ${efMatchNumber} not found`);
+    // The row for the match being advanced may predate this result, so use the winner
-    if (efMatch.participant2Id) throw new Error(`EF ${efMatchNumber} participant2 already filled`);
+    // passed in rather than whatever the read returned.
+    const winnerByMatchNumber = new Map<number, string>();
+    for (const wc of wcMatches) {
+      const decidedWinner = wc.id === match.id ? winnerId : wc.isComplete ? wc.winnerId : null;
+      if (decidedWinner) winnerByMatchNumber.set(wc.matchNumber, decidedWinner);
+    }
 
-    await updatePlayoffMatch(efMatch.id, { participant2Id: winnerId });
+    const results: AflWildcardResult[] = wcMatches.map((wc) => {
+      const decidedWinner = winnerByMatchNumber.get(wc.matchNumber) ?? null;
+      if (decidedWinner === null) return { matchNumber: wc.matchNumber, winnerSlot: null };
+      if (decidedWinner === wc.participant1Id) return { matchNumber: wc.matchNumber, winnerSlot: 1 };
+      if (decidedWinner === wc.participant2Id) return { matchNumber: wc.matchNumber, winnerSlot: 2 };
+      throw new Error(
+        `Wildcard Round match ${wc.matchNumber} winner is not one of its participants`
+      );
+    });
+
+    const wanted = new Map<number, string>();
+    for (const placement of resolveAflWildcardPlacements(results)) {
+      const placedWinner = winnerByMatchNumber.get(placement.wildcardMatchNumber);
+      if (placedWinner) wanted.set(placement.eliminationMatchNumber, placedWinner);
+    }
+
+    // Only these teams can legitimately be moved between the two Elimination Finals;
+    // anyone else in a slot came from somewhere this function knows nothing about.
+    const wildcardParticipants = new Set<string>();
+    for (const wc of wcMatches) {
+      if (wc.participant1Id) wildcardParticipants.add(wc.participant1Id);
+      if (wc.participant2Id) wildcardParticipants.add(wc.participant2Id);
+    }
+
+    const slotsToClear: string[] = [];
+    const slotsToFill: Array<{ id: string; participantId: string }> = [];
+
+    for (const efMatch of efMatches) {
+      const occupant = efMatch.participant2Id;
+      const belongsHere = wanted.get(efMatch.matchNumber) ?? null;
+      if (occupant === belongsHere) continue;
+
+      if (occupant !== null && !wildcardParticipants.has(occupant)) {
+        throw new Error(`EF ${efMatch.matchNumber} participant2 already filled`);
+      }
+      // A Wildcard team in the wrong slot is a placement this result supersedes: a
+      // corrected Wildcard winner, or one placed before the re-seeding rule existed.
+      if (occupant !== null) slotsToClear.push(efMatch.id);
+      if (belongsHere !== null) slotsToFill.push({ id: efMatch.id, participantId: belongsHere });
+    }
+
+    if (slotsToClear.length === 0 && slotsToFill.length === 0) return;
+
+    // One transaction, vacating before filling: a half-applied re-seed would leave the
+    // same team in both Elimination Finals.
+    const db = database();
+    await db.transaction(async (tx) => {
+      const now = new Date();
+      for (const id of slotsToClear) {
+        await tx
+          .update(schema.playoffMatches)
+          .set({ participant2Id: null, updatedAt: now })
+          .where(eq(schema.playoffMatches.id, id));
+      }
+      for (const { id, participantId } of slotsToFill) {
+        await tx
+          .update(schema.playoffMatches)
+          .set({ participant2Id: participantId, updatedAt: now })
+          .where(eq(schema.playoffMatches.id, id));
+      }
+    });
     return;
   }
 

app/services/simulations/__tests__/afl-simulator.test.ts

@@ -5,6 +5,7 @@ import {
   eloWinProbability,
   AFLSimulator,
   readAflBracketSeeds,
+  simAFLFinals,
   type BracketMatch,
 } from "../afl-simulator";
 import { DEFAULT_SCORING_RULES } from "~/lib/scoring-types";
@@ -623,3 +624,62 @@ describe("readAflBracketSeeds", () => {
     expect(() => readAflBracketSeeds(matches, teamsById as never)).toThrow(/not in this sports season/);
   });
 });
+
+// ─── simAFLFinals ─────────────────────────────────────────────────────────────
+
+describe("simAFLFinals Elimination Finals re-seeding", () => {
+  const finalists = Array.from({ length: 10 }, (_, i) => ({
+    id: `s${i + 1}`,
+    name: `s${i + 1}`,
+    elo: 1500,
+    currentWins: 0,
+    remainingGames: 0,
+    winProb: 0.5,
+  }));
+
+  /**
+   * Play the finals with the Wildcard Round forced to the given winners (every other
+   * game goes to whoever was routed in first), and report who met whom.
+   */
+  function pairingsWith(wc1Winner: string, wc2Winner: string): Map<string, [string, string]> {
+    const pairings = new Map<string, [string, string]>();
+    const play = (
+      round: string,
+      matchNumber: number,
+      t1: { id: string },
+      t2: { id: string }
+    ) => {
+      pairings.set(`${round}#${matchNumber}`, [t1.id, t2.id]);
+      if (round === "Wildcard Round") {
+        const forced = matchNumber === 1 ? wc1Winner : wc2Winner;
+        return t1.id === forced ? { winner: t1, loser: t2 } : { winner: t2, loser: t1 };
+      }
+      return { winner: t1, loser: t2 };
+    };
+
+    simAFLFinals(finalists as never, play as never);
+    return pairings;
+  }
+
+  it("draws the Wildcard Round 7v10 and 8v9", () => {
+    const pairings = pairingsWith("s7", "s8");
+    expect(pairings.get("Wildcard Round#1")).toEqual(["s7", "s10"]);
+    expect(pairings.get("Wildcard Round#2")).toEqual(["s8", "s9"]);
+  });
+
+  it.each([
+    { wc1: "s7", wc2: "s8", ef1: "s8", ef2: "s7" },
+    { wc1: "s7", wc2: "s9", ef1: "s9", ef2: "s7" },
+    // 10th beating 7th is where a fixed crossover misfires: it would send 10th to 6th
+    // and leave 5th with the stronger survivor.
+    { wc1: "s10", wc2: "s8", ef1: "s10", ef2: "s8" },
+    { wc1: "s10", wc2: "s9", ef1: "s10", ef2: "s9" },
+  ])(
+    "pairs 5th with $ef1 and 6th with $ef2 when $wc1 and $wc2 win through",
+    ({ wc1, wc2, ef1, ef2 }) => {
+      const pairings = pairingsWith(wc1, wc2);
+      expect(pairings.get("Elimination Finals#1")).toEqual(["s5", ef1]);
+      expect(pairings.get("Elimination Finals#2")).toEqual(["s6", ef2]);
+    }
+  );
+});

app/services/simulations/afl-simulator.ts

@@ -37,7 +37,8 @@
  *         Wildcard Round:       #7 vs #10, #8 vs #9         → losers exit (0 pts)
  *         Qualifying Finals:    #1 vs #4,  #2 vs #3         → winners → Prelim Finals (bye)
  *                                                              losers → Semi-Finals (2nd chance)
- *         Elimination Finals:   #5 vs WC2w, #6 vs WC1w     → losers exit (7th/8th)
+ *         Elimination Finals:   #5 vs lower WC winner,      → losers exit (7th/8th)
+ *                               #6 vs higher WC winner
  *         Semi-Finals:          QF1L vs EF2w, QF2L vs EF1w → losers exit (5th/6th)
  *         Preliminary Finals:   QF1w vs SF2w, QF2w vs SF1w → losers exit (3rd/4th)
  *         Grand Final:          PF1w vs PF2w               → winner 1st, loser 2nd
@@ -409,9 +410,14 @@ export function simAFLFinals(
   const qf1 = play("Qualifying Finals", 1, s1, s4);
   const qf2 = play("Qualifying Finals", 2, s2, s3);
 
-  // Elimination Finals: #5 vs WC2 winner, #6 vs WC1 winner
+  // Elimination Finals: the Wildcard winners are re-seeded by ladder position, so #5
-  const ef1 = play("Elimination Finals", 1, s5, wc2.winner);
+  // hosts whichever finished lower and #6 the other — not a fixed crossover.
-  const ef2 = play("Elimination Finals", 2, s6, wc1.winner);
+  const wc1Seed = wc1.winner === s7 ? 7 : 10;
+  const wc2Seed = wc2.winner === s8 ? 8 : 9;
+  const [betterWc, worseWc] =
+    wc1Seed < wc2Seed ? [wc1.winner, wc2.winner] : [wc2.winner, wc1.winner];
+  const ef1 = play("Elimination Finals", 1, s5, worseWc);
+  const ef2 = play("Elimination Finals", 2, s6, betterWc);
 
   // Semi-Finals: QF losers (second chance) vs EF winners
   const sf1 = play("Semi-Finals", 1, qf1.loser, ef2.winner);