/**
 * 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));
  });
});