Added Section 179 Limits

server/services/section179Limits.js

@@ -0,0 +1,95 @@
+const { all, audit, now, one, run } = require('../db');
+
+let cache = null;
+
+function clearCache() {
+  cache = null;
+}
+
+// Sorted ascending by tax_year, cached for the engine.
+function rows() {
+  if (!cache) cache = all('SELECT * FROM section_179_limits ORDER BY tax_year');
+  return cache;
+}
+
+// Applicable limit for a placed-in-service year: the most recent year at or before it.
+// Returns null when nothing is configured for/under the year, so the engine leaves §179 uncapped.
+function getLimit(year) {
+  const y = Number(year);
+  if (!y) return null;
+  let match = null;
+  for (const row of rows()) {
+    if (row.tax_year <= y) match = row;
+    else break;
+  }
+  return match;
+}
+
+function fromRow(row) {
+  return {
+    id: row.id,
+    tax_year: row.tax_year,
+    base_limit: row.base_limit,
+    phaseout_threshold: row.phaseout_threshold
+  };
+}
+
+function list() {
+  return all('SELECT * FROM section_179_limits ORDER BY tax_year DESC').map(fromRow);
+}
+
+function normalize(body) {
+  return {
+    tax_year: Math.trunc(Number(body.tax_year)) || 0,
+    base_limit: Number(body.base_limit) || 0,
+    phaseout_threshold: Number(body.phaseout_threshold) || 0
+  };
+}
+
+function createLimit(body, userId) {
+  const input = normalize(body);
+  if (!input.tax_year) throw Object.assign(new Error('A valid tax year is required'), { status: 400 });
+  if (one('SELECT id FROM section_179_limits WHERE tax_year = ?', [input.tax_year])) {
+    throw Object.assign(new Error('A limit for that tax year already exists'), { status: 400 });
+  }
+  const ts = now();
+  run(
+    `INSERT INTO section_179_limits (tax_year, base_limit, phaseout_threshold, created_at, updated_at)
+     VALUES (?, ?, ?, ?, ?)`,
+    [input.tax_year, input.base_limit, input.phaseout_threshold, ts, ts]
+  );
+  clearCache();
+  audit(userId, 'create', 'section_179_limit', String(input.tax_year), null, input);
+  return fromRow(one('SELECT * FROM section_179_limits WHERE tax_year = ?', [input.tax_year]));
+}
+
+function updateLimit(taxYear, body, userId) {
+  const before = one('SELECT * FROM section_179_limits WHERE tax_year = ?', [Number(taxYear)]);
+  if (!before) return null;
+  const input = normalize({ ...before, ...body, tax_year: before.tax_year });
+  run(
+    'UPDATE section_179_limits SET base_limit = ?, phaseout_threshold = ?, updated_at = ? WHERE tax_year = ?',
+    [input.base_limit, input.phaseout_threshold, now(), before.tax_year]
+  );
+  clearCache();
+  audit(userId, 'update', 'section_179_limit', String(before.tax_year), before, input);
+  return fromRow(one('SELECT * FROM section_179_limits WHERE tax_year = ?', [before.tax_year]));
+}
+
+function deleteLimit(taxYear, userId) {
+  const before = one('SELECT * FROM section_179_limits WHERE tax_year = ?', [Number(taxYear)]);
+  if (!before) return false;
+  run('DELETE FROM section_179_limits WHERE tax_year = ?', [before.tax_year]);
+  clearCache();
+  audit(userId, 'delete', 'section_179_limit', String(before.tax_year), before, null);
+  return true;
+}
+
+module.exports = {
+  clearCache,
+  createLimit,
+  deleteLimit,
+  getLimit,
+  list,
+  updateLimit
+};