'use strict';

// B9: export → import round-trip must preserve money exactly. The export writes
// dollars (fromCents) into REAL columns and has no schema_migrations table, so the
// import treats it as dollars and applies toCents — a symmetric conversion. This
// guards against that symmetry breaking (which would 100x amounts on import).
const test = require('node:test');
const assert = require('node:assert/strict');
const os = require('node:os');
const path = require('node:path');
const fs = require('node:fs');

const dbPath = path.join(os.tmpdir(), `bill-tracker-roundtrip-test-${process.pid}.sqlite`);
process.env.DB_PATH = dbPath;

const { getDb, closeDb } = require('../db/database');
const { buildUserDbExportFile } = require('../routes/export');
const { previewUserDbImport, applyUserDbImport } = require('../services/userDbImportService');

const mkUser = (db, name) =>
  db.prepare("INSERT INTO users (username, password_hash, role, active) VALUES (?, 'x', 'user', 1)").run(name).lastInsertRowid;

test('export → import round-trip preserves money in cents (no 100x drift)', async () => {
  const db = getDb();
  const userA = mkUser(db, 'rt-a');
  const userB = mkUser(db, 'rt-b');

  const catA = db.prepare("INSERT INTO categories (user_id, name) VALUES (?, 'Utilities')").run(userA).lastInsertRowid;
  const billA = db.prepare(`
    INSERT INTO bills (user_id, name, category_id, due_day, billing_cycle, cycle_type, expected_amount, active)
    VALUES (?, 'Electric Company', ?, 15, 'monthly', 'monthly', 8500, 1)
  `).run(userA, catA).lastInsertRowid; // $85.00
  db.prepare("INSERT INTO payments (bill_id, amount, paid_date, payment_source) VALUES (?, 8500, '2026-06-15', 'manual')").run(billA);
  db.prepare('INSERT INTO monthly_bill_state (bill_id, year, month, actual_amount) VALUES (?, 2026, 7, 5000)').run(billA); // $50 override

  // Export user A, import into fresh user B.
  const file = buildUserDbExportFile(userA);
  try {
    const buffer = fs.readFileSync(file);
    const preview = await previewUserDbImport(userB, buffer, {});
    assert.ok(preview.import_session_id, 'preview returns an import session id');
    await applyUserDbImport(userB, preview.import_session_id, {});
  } finally {
    try { fs.unlinkSync(file); } catch { /* ignore */ }
  }

  const billB = db.prepare("SELECT expected_amount FROM bills WHERE user_id = ? AND name = 'Electric Company'").get(userB);
  assert.ok(billB, 'bill imported for user B');
  assert.equal(billB.expected_amount, 8500, 'bill expected_amount preserved as cents');

  const payB = db.prepare('SELECT p.amount FROM payments p JOIN bills b ON b.id = p.bill_id WHERE b.user_id = ?').get(userB);
  assert.equal(payB.amount, 8500, 'payment amount preserved as cents');

  const stateB = db.prepare('SELECT m.actual_amount FROM monthly_bill_state m JOIN bills b ON b.id = m.bill_id WHERE b.user_id = ?').get(userB);
  assert.equal(stateB.actual_amount, 5000, 'per-month override preserved as cents');
});

test.after(() => {
  closeDb();
  for (const suffix of ['', '-wal', '-shm']) {
    try { fs.rmSync(dbPath + suffix); } catch { /* ignore */ }
  }
});