import "../../setup.ts";
import { assert, assertEquals } from "@std/assert";
import { DatabaseSync } from "node:sqlite";
import { up as up0020 } from "../../../db/migrations/0020_digest_schedule.ts";

Deno.test("migration 0020 spreads existing users' first digests over the coming period", () => {
  const db = new DatabaseSync(":memory:");
  db.exec(`CREATE TABLE users (id TEXT PRIMARY KEY);`);
  const ids = Array.from({ length: 40 }, () => crypto.randomUUID());
  for (const id of ids) {
    db.prepare(`INSERT INTO users (id) VALUES (?);`).run(id);
  }
  const before = Date.now();
  up0020(db);
  up0020(db); // idempotent
  const rows = db.prepare(
    `SELECT user_id, cadence, window_start FROM digest_schedule;`,
  ).all() as { user_id: string; cadence: string; window_start: string }[];
  assertEquals(rows.length, 80);
  const due = (cadence: string, days: number) =>
    rows.filter((r) => r.cadence === cadence).map((r) =>
      new Date(r.window_start).getTime() + days * 86_400_000
    );
  for (const [cadence, days] of [["weekly", 7], ["monthly", 30]] as const) {
    const dues = due(cadence, days);
    // Each first digest falls due within the coming period, not all at once.
    assert(
      dues.every((t) =>
        t >= before - 1000 && t <= Date.now() + days * 86_400_000
      ),
    );
    assert(new Set(dues.map((t) => Math.floor(t / 3_600_000))).size > 10);
  }
  db.close();
});