feat(date): add parseDate utility with locale-aware parsing

src/renderer/lib/parseDate.ts

@@ -0,0 +1,146 @@
+import type { FormatPrefs } from './date';
+
+type ParseInput = string | null | undefined;
+
+const RE_REL = /^\s*([+-])\s*(\d+)\s*([dwm])\s*$/i;
+const RE_NUMERIC = /^(\d{1,4})[/\-.](\d{1,4})(?:[/\-.](\d{1,4}))?$/;
+
+function startOfDay(d: Date): Date {
+  const out = new Date(d.getFullYear(), d.getMonth(), d.getDate());
+  return out;
+}
+
+function addDays(d: Date, n: number): Date {
+  const out = new Date(d);
+  out.setDate(out.getDate() + n);
+  return out;
+}
+
+function addMonths(d: Date, n: number): Date {
+  const out = new Date(d);
+  out.setMonth(out.getMonth() + n);
+  return out;
+}
+
+function pivotYear(twoDigit: number): number {
+  const now = new Date().getFullYear();
+  const century = Math.floor(now / 100) * 100;
+  const offset = now % 100;
+  return twoDigit > (offset + 50) ? century - 100 + twoDigit : century + twoDigit;
+}
+
+function parseNumeric(
+  input: string,
+  prefs: FormatPrefs,
+  base: Date,
+): Date | null {
+  const m = input.match(RE_NUMERIC);
+  if (!m) return null;
+  let day: number, month: number, year: number;
+  const a = parseInt(m[1], 10);
+  const b = parseInt(m[2], 10);
+  const c = m[3] != null ? parseInt(m[3], 10) : NaN;
+
+  if (prefs.dateFormat === 'yyyy-MM-dd') {
+    if (m[3] == null) return null;
+    year = a; month = b; day = c;
+  } else if (prefs.dateFormat === 'MM/dd/yyyy') {
+    month = a; day = b;
+    if (m[3] == null) year = base.getFullYear();
+    else year = c < 100 ? pivotYear(c) : c;
+  } else {
+    // default: 'dd/MM/yyyy'
+    day = a; month = b;
+    if (m[3] == null) year = base.getFullYear();
+    else year = c < 100 ? pivotYear(c) : c;
+  }
+
+  if (month < 1 || month > 12) return null;
+  const result = new Date(year, month - 1, day);
+  if (result.getFullYear() !== year || result.getMonth() !== month - 1 || result.getDate() !== day) {
+    return null;
+  }
+  if (m[3] == null && result < startOfDay(base)) {
+    result.setFullYear(year + 1);
+  }
+  return result;
+}
+
+function parseKeyword(
+  word: string,
+  keywords: { today: string[]; tomorrow: string[]; yesterday: string[]; weekdays: string[][] },
+  base: Date,
+): Date | null {
+  const w = word.trim().toLowerCase();
+  if (keywords.today.some((k) => k.toLowerCase() === w)) return startOfDay(base);
+  if (keywords.tomorrow.some((k) => k.toLowerCase() === w)) return addDays(startOfDay(base), 1);
+  if (keywords.yesterday.some((k) => k.toLowerCase() === w)) return addDays(startOfDay(base), -1);
+  for (let i = 0; i < keywords.weekdays.length; i++) {
+    if (keywords.weekdays[i].some((k) => k.toLowerCase() === w)) {
+      const today = startOfDay(base);
+      const diff = (i - today.getDay() + 7) % 7 || 7;
+      return addDays(today, diff);
+    }
+  }
+  return null;
+}
+
+export type DateKeywords = {
+  today: string[];
+  tomorrow: string[];
+  yesterday: string[];
+  /** Index 0=Sunday, 6=Saturday. Each entry: aliases (short + long). */
+  weekdays: string[][];
+};
+
+export function parseDate(
+  input: ParseInput,
+  prefs: FormatPrefs,
+  keywords: DateKeywords,
+  baseDate: Date = new Date(),
+): Date | null {
+  if (!input) return null;
+  const trimmed = input.trim();
+  if (!trimmed) return null;
+
+  const rel = trimmed.match(RE_REL);
+  if (rel) {
+    const sign = rel[1] === '-' ? -1 : 1;
+    const n = sign * parseInt(rel[2], 10);
+    const unit = rel[3].toLowerCase();
+    const base = startOfDay(baseDate);
+    if (unit === 'd') return addDays(base, n);
+    if (unit === 'w') return addDays(base, n * 7);
+    if (unit === 'm') return addMonths(base, n);
+  }
+
+  const kw = parseKeyword(trimmed, keywords, baseDate);
+  if (kw) return kw;
+
+  const num = parseNumeric(trimmed, prefs, baseDate);
+  if (num) return num;
+
+  return null;
+}
+
+export function parseDateRange(
+  input: ParseInput,
+  prefs: FormatPrefs,
+  keywords: DateKeywords,
+  baseDate: Date = new Date(),
+): { from: Date; to?: Date } | null {
+  if (!input) return null;
+  const parts = input.split(/\s*(?:-{1,2}|–|to)\s*/i);
+  if (parts.length === 1) {
+    const single = parseDate(parts[0], prefs, keywords, baseDate);
+    return single ? { from: single } : null;
+  }
+  if (parts.length === 2) {
+    const from = parseDate(parts[0], prefs, keywords, baseDate);
+    if (!from) return null;
+    const to = parseDate(parts[1], prefs, keywords, from);
+    if (!to) return null;
+    return { from, to };
+  }
+  return null;
+}