import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { eq, siteConfig } from "@parking/db";
import { createTestDb } from "@parking/db/testing";
import { afterEach, beforeEach, describe, expect, it } from "vitest";
import { BackupService } from "./backup-service.js";

// BackupService previously tracked last-success/last-error as plain in-process fields, so a
// server restart (a fresh BackupService instance, exactly as happens on every deploy/crash/OOM
// reboot under `restart: always`) silently reset the admin UI to "last successful backup:
// Never" — even with valid, correctly-rotating backups already on disk (2026-08-30 field
// incident, park-buzi). These tests exercise the fix: status is read from site_config, so a new
// BackupService instance pointed at the same DB sees the prior instance's last-run outcome, and
// the schedule is wall-clock-based (isDue()) rather than time-since-process-start.
// See wiki/concepts/backup-recovery.md.

const KEY = "a-test-backup-key-that-is-long-enough";

let workDir: string;
let target: string;

beforeEach(() => {
  workDir = mkdtempSync(join(tmpdir(), "pk-backup-service-test-"));
  target = join(workDir, "target");
  process.env.BACKUP_KEY = KEY;
});

afterEach(() => {
  rmSync(workDir, { recursive: true, force: true });
  delete process.env.BACKUP_KEY;
});

function setTargetDir(db: ReturnType<typeof createTestDb>["db"], dir: string): void {
  const existing = db.select().from(siteConfig).where(eq(siteConfig.id, 1)).get();
  if (existing) {
    db.update(siteConfig).set({ backupTargetDir: dir }).where(eq(siteConfig.id, 1)).run();
  } else {
    db.insert(siteConfig).values({ id: 1, backupTargetDir: dir }).run();
  }
}

describe("BackupService — persisted status survives a restart", () => {
  it("a fresh instance sees the previous instance's last success", async () => {
    const t = createTestDb();
    setTargetDir(t.db, target);

    const first = new BackupService(t.db);
    expect(first.status().lastSuccessAt).toBeNull();
    const result = await first.run("manual");

    // Simulate a process restart: a brand-new BackupService over the SAME db handle (in
    // production this would be a fresh process re-opening the same sqlite file).
    const second = new BackupService(t.db);
    const status = second.status();
    expect(status.lastSuccessAt).not.toBeNull();
    expect(status.lastResult).toEqual({ path: result.path, bytes: result.bytes, prunedFiles: result.prunedFiles });
    expect(status.lastError).toBeNull();

    t.close();
  });

  it("a fresh instance sees the previous instance's last error, and it clears on next success", async () => {
    const t = createTestDb();
    // Target dir set, but as a FILE (not a directory) — runBackup's mkdir(recursive) will
    // throw, giving us a real, deterministic failure without needing to mock anything.
    const badTarget = join(workDir, "not-a-dir");
    writeFileSync(badTarget, "x");
    setTargetDir(t.db, badTarget);

    const first = new BackupService(t.db);
    await expect(first.run("manual")).rejects.toThrow();

    const second = new BackupService(t.db);
    const status = second.status();
    expect(status.lastError).not.toBeNull();
    expect(status.lastErrorAt).not.toBeNull();
    expect(status.lastSuccessAt).toBeNull();

    // Now point at a real directory and succeed — the persisted error must clear.
    setTargetDir(t.db, target);
    await second.run("manual");
    const third = new BackupService(t.db);
    const finalStatus = third.status();
    expect(finalStatus.lastSuccessAt).not.toBeNull();
    expect(finalStatus.lastError).toBeNull();
    expect(finalStatus.lastErrorAt).toBeNull();

    t.close();
  });
});

describe("BackupService — isDue() is wall-clock-based, not process-uptime-based", () => {
  it("is due immediately when no success has ever been recorded", () => {
    const t = createTestDb();
    const svc = new BackupService(t.db);
    expect(svc.isDue()).toBe(true);
    t.close();
  });

  it("is NOT due right after a fresh instance is constructed, if a recent success is persisted", async () => {
    const t = createTestDb();
    setTargetDir(t.db, target);
    const first = new BackupService(t.db);
    await first.run("manual");

    // The whole point of the fix: a brand-new instance (simulating a restart moments after a
    // real backup completed) must NOT think a backup is due just because ITS OWN uptime is ~0.
    const second = new BackupService(t.db);
    expect(second.isDue()).toBe(false);
    t.close();
  });

  it("is due once the persisted last-success timestamp is old enough", async () => {
    const t = createTestDb();
    setTargetDir(t.db, target);
    const svc = new BackupService(t.db);
    await svc.run("manual");

    const almostADayLater = new Date(Date.now() + 23 * 60 * 60 * 1000);
    expect(svc.isDue(almostADayLater)).toBe(false);

    const overADayLater = new Date(Date.now() + 24 * 60 * 60 * 1000 + 1000);
    expect(svc.isDue(overADayLater)).toBe(true);
    t.close();
  });

  it("runScheduled() is a no-op when not yet due, even if configured", async () => {
    const t = createTestDb();
    setTargetDir(t.db, target);
    const svc = new BackupService(t.db);
    await svc.run("manual");
    const afterFirst = svc.status().lastSuccessAt;

    await svc.runScheduled(); // not due yet — must not run again
    expect(svc.status().lastSuccessAt).toBe(afterFirst);
    t.close();
  });
});