import { beforeEach, describe, expect, it } from "vitest";
import { FieldValue, Timestamp } from "firebase-admin/firestore";
import { firestore } from "../../src/firebase";
import {
  getSeasonRecords,
  maybeSettleSeason,
} from "../../src/services/seasonService";
import type { DateString } from "../../src/types/dateString";
import type { SeasonHistoryDoc } from "../../src/types/season";
import type { User } from "../../src/types/panit";

const END: DateString = "2026-10-30" as DateString;
const BEFORE_END: DateString = "2026-10-30" as DateString;
const AFTER_END: DateString = "2026-10-31" as DateString;

async function seedSeasonConfig(
  patch: Record<string, unknown> = {}
): Promise<void> {
  await firestore.collection("config").doc("season").set({
    id: "2026",
    startDate: "2026-03-28",
    endDate: END,
    ...patch,
  });
}

async function seedUser(
  uid: string,
  patch: Partial<User> & Record<string, unknown> = {}
): Promise<void> {
  await firestore.collection("users").doc(uid).set({
    displayName: uid,
    email: `${uid}@e.com`,
    provider: "google",
    knowledgeLevel: "beginner",
    createdAt: Timestamp.now(),
    active: true,
    ...patch,
  });
}

async function readUser(uid: string): Promise<Partial<User>> {
  const snap = await firestore.collection("users").doc(uid).get();
  return (snap.data() ?? {}) as Partial<User>;
}

async function readHistory(
  uid: string,
  seasonId = "2026"
): Promise<Partial<SeasonHistoryDoc> | null> {
  const snap = await firestore
    .collection("users")
    .doc(uid)
    .collection("seasonHistory")
    .doc(seasonId)
    .get();
  return snap.exists ? (snap.data() as Partial<SeasonHistoryDoc>) : null;
}

describe("seasonService.maybeSettleSeason", () => {
  beforeEach(async () => {
    await firestore.recursiveDelete(firestore.collection("users"));
    await firestore.recursiveDelete(
      firestore.collection("config").doc("season")
    );
  });

  it("config/season이 없으면 no-op", async () => {
    await seedUser("a", { tierPoints: 600 });
    const result = await maybeSettleSeason(AFTER_END);
    expect(result.settled).toBe(false);
    expect((await readUser("a")).tierPoints).toBe(600);
  });

  it("endDate 당일까지는 no-op (마지막 날 판정 완료 후 다음 날 정산)", async () => {
    await seedSeasonConfig();
    await seedUser("a", { tierPoints: 600 });
    const result = await maybeSettleSeason(BEFORE_END);
    expect(result.settled).toBe(false);
    expect((await readUser("a")).tierPoints).toBe(600);
    expect(await readHistory("a")).toBeNull();
  });

  it("endDate 다음 날 정산: 아카이브·rank(동점 동일)·리셋·settledAt", async () => {
    await seedSeasonConfig();
    await seedUser("gold", {
      tierPoints: 600,
      rankSnapshot: { date: END, overall: 1 },
    });
    await seedUser("tie1", { tierPoints: 200 });
    await seedUser("tie2", { tierPoints: 200 });
    // 비활성 유저는 랭킹 모집단이 아니므로 정산·리셋 대상도 아니다.
    await seedUser("ghost", { tierPoints: 999, active: false });

    const result = await maybeSettleSeason(AFTER_END);
    expect(result).toEqual({ settled: true, users: 3 });

    const gold = await readHistory("gold");
    expect(gold).toMatchObject({
      seasonId: "2026",
      tierPoints: 600,
      tier: "ST", // 500 <= 600 < 1200
      rank: 1,
      totalRanked: 3,
    });
    expect((await readHistory("tie1"))?.rank).toBe(2);
    expect((await readHistory("tie2"))?.rank).toBe(2);
    expect((await readHistory("tie1"))?.tier).toBe("PR"); // 150 <= 200 < 500

    const goldUser = await readUser("gold");
    expect(goldUser.tierPoints).toBe(0);
    expect(goldUser.rankSnapshot).toBeUndefined();
    expect((await readUser("tie1")).tierPoints).toBe(0);

    expect((await readUser("ghost")).tierPoints).toBe(999);
    expect(await readHistory("ghost")).toBeNull();

    const config = await firestore.collection("config").doc("season").get();
    expect(config.data()?.settledAt).toBeInstanceOf(Timestamp);
  });

  it("settledAt이 있으면 재실행해도 no-op (멱등)", async () => {
    await seedSeasonConfig({ settledAt: Timestamp.now() });
    await seedUser("a", { tierPoints: 600 });
    const result = await maybeSettleSeason(AFTER_END);
    expect(result.settled).toBe(false);
    expect((await readUser("a")).tierPoints).toBe(600);
    expect(await readHistory("a")).toBeNull();
  });

  it("부분 실패 재실행: 기정산 유저 점수를 순위에 합류시켜 rank가 보존된다", async () => {
    await seedSeasonConfig();
    // 첫 실행에서 1위(600pt)만 정산된 뒤 실패했다고 가정 —
    // 이미 아카이브 + 리셋된 상태이고 settledAt은 아직 없다.
    await seedUser("done", { tierPoints: 0 });
    await firestore
      .collection("users")
      .doc("done")
      .collection("seasonHistory")
      .doc("2026")
      .set({
        seasonId: "2026",
        tierPoints: 600,
        tier: "ST",
        rank: 1,
        totalRanked: 3,
        settledAt: FieldValue.serverTimestamp(),
      });
    await seedUser("b", { tierPoints: 300 });
    await seedUser("c", { tierPoints: 100 });

    const result = await maybeSettleSeason(AFTER_END);
    expect(result).toEqual({ settled: true, users: 2 });

    // done(600)이 순위표에 합류했으므로 b는 2위, c는 3위가 된다.
    expect(await readHistory("b")).toMatchObject({
      tierPoints: 300,
      rank: 2,
      totalRanked: 3,
    });
    expect(await readHistory("c")).toMatchObject({
      tierPoints: 100,
      rank: 3,
      totalRanked: 3,
    });
    // 기정산 유저의 아카이브는 덮어쓰지 않는다.
    expect((await readHistory("done"))?.rank).toBe(1);
    expect((await readUser("b")).tierPoints).toBe(0);
  });

  it("getSeasonRecords: 정산 전 빈 목록, 정산 후 최근 시즌부터 DTO 반환", async () => {
    await seedUser("a");
    expect(await getSeasonRecords("a")).toEqual([]);

    const history = firestore
      .collection("users")
      .doc("a")
      .collection("seasonHistory");
    await history.doc("2025").set({
      seasonId: "2025",
      tierPoints: 300,
      tier: "PR",
      rank: 5,
      totalRanked: 10,
      settledAt: Timestamp.now(),
    });
    await history.doc("2026").set({
      seasonId: "2026",
      tierPoints: 900,
      tier: "ST",
      rank: 2,
      totalRanked: 12,
      settledAt: Timestamp.now(),
    });

    const records = await getSeasonRecords("a");
    expect(records.map((r) => r.seasonId)).toEqual(["2026", "2025"]);
    expect(records[0]).toMatchObject({
      tierPoints: 900,
      tier: "ST",
      rank: 2,
      totalRanked: 12,
    });
    // Timestamp가 그대로 유출되지 않고 ISO 문자열로 변환된다.
    expect(typeof records[0].settledAt).toBe("string");
  });
});