import { beforeEach, describe, expect, mock, test } from "bun:test";
import { Database } from "bun:sqlite";
import { readFileSync } from "node:fs";
import { fakeD1 } from "./fake-d1.test-helper";

let d1 = fakeD1();
mock.module("cloudflare:workers", () => ({
  env: {
    get DB() {
      return d1.binding;
    },
  },
  waitUntil: () => undefined,
}));
const { ACCOUNT_SCHEMA } = await import("../scoped-db/schema.gen");
const { leaderboardRows, publishUsageLeaderboard } = await import("./leaderboard");

const NOW = Date.parse("2026-10-01T00:03:00Z");

function account(id: string, usage: Array<[string, string, number]>) {
  const db = new Database(":memory:");
  for (const statement of ACCOUNT_SCHEMA) db.run(statement);
  for (const [meter, period, quantity] of usage) {
    db.query(
      "INSERT INTO usage_periods (account_id, meter, period, quantity, reserved, updated_at) VALUES (?, ?, ?, ?, 0, 0)",
    ).run(id, meter, period, quantity);
  }
  return {
    db,
    sql: {
      exec: (query: string, ...params: Array<string | number | null>) => {
        const rows = db.query(query).all(...params) as never[];
        return { toArray: () => rows };
      },
    },
  };
}

beforeEach(() => {
  d1 = fakeD1();
  d1.db.exec(readFileSync(new URL("../../../migrations/0063_usage_leaderboard.sql", import.meta.url), "utf8"));
});

describe("usage leaderboard", () => {
  test("accounts publish this and last period, and the ranking keeps the heaviest per meter", async () => {
    const a = account("a", [
      ["compute.ci", "2026-10", 5],
      ["compute.ci", "2026-09", 50],
    ]);
    const b = account("b", [["compute.ci", "2026-10", 9]]);
    const c = account("c", [["compute.ci", "2026-10", 1]]);
    for (const [id, store] of [
      ["a", a],
      ["b", b],
      ["c", c],
    ] as const)
      await publishUsageLeaderboard(id, store.sql, NOW);
    expect(await leaderboardRows("2026-10", 2)).toEqual([
      { account_id: "b", meter: "compute.ci", quantity: 9 },
      { account_id: "a", meter: "compute.ci", quantity: 5 },
    ]);
    expect(await leaderboardRows("2026-09", 2)).toEqual([{ account_id: "a", meter: "compute.ci", quantity: 50 }]);
    b.db.run("DELETE FROM usage_periods");
    await publishUsageLeaderboard("b", b.sql, NOW);
    expect((await leaderboardRows("2026-10", 5)).map((row) => row.account_id)).toEqual(["a", "c"]);
  });
});