Add mobile expenses and receipt OCR

lib/receipt-parse.ts

@@ -0,0 +1,128 @@
+export type ReceiptParseResult = {
+  amount: number | null;
+  date: Date | null;
+  subtotal: number | null;
+  tax: number | null;
+  vendor: string | null;
+  items: ReceiptLineItem[];
+  rawLines: string[];
+};
+
+export type ReceiptLineItem = {
+  id: string;
+  name: string;
+  amount: number;
+  rawLine: string;
+};
+
+const AMOUNT_PATTERNS = [
+  /(?:total|amount due|balance due|grand total)[:\s]*\$?\s*([\d,]+\.\d{2})/i,
+  /\$\s*([\d,]+\.\d{2})\s*(?:total|due)?/i,
+  /(?:USD|CAD|EUR)\s*([\d,]+\.\d{2})/i,
+];
+
+const DATE_PATTERNS = [
+  /(\d{1,2}[/.-]\d{1,2}[/.-]\d{2,4})/,
+  /(\d{4}[/.-]\d{1,2}[/.-]\d{1,2})/,
+];
+
+const SUBTOTAL_PATTERNS = [
+  /(?:sub\s?total|subtotal)[:\s]*\$?\s*([\d,]+\.\d{2})/i,
+];
+
+const TAX_PATTERNS = [
+  /(?:tax|sales tax|hst|gst|pst|vat)[:\s]*\$?\s*([\d,]+\.\d{2})/i,
+];
+
+const NON_ITEM_LINE =
+  /(?:total|subtotal|sub total|tax|tip|gratuity|change|cash|visa|mastercard|amex|discover|card|credit|debit|balance|amount due|auth|approval|terminal|merchant|receipt|order|invoice|thank|powered by)/i;
+
+function parseAmount(text: string): number | null {
+  for (const pattern of AMOUNT_PATTERNS) {
+    const match = text.match(pattern);
+    if (!match?.[1]) continue;
+    const value = Number(match[1].replace(/,/g, ""));
+    if (Number.isFinite(value) && value > 0) return value;
+  }
+
+  const amounts = [...text.matchAll(/\$\s*([\d,]+\.\d{2})/g)]
+    .map((m) => Number(m[1]!.replace(/,/g, "")))
+    .filter((n) => Number.isFinite(n) && n > 0);
+
+  return amounts.length > 0 ? Math.max(...amounts) : null;
+}
+
+function parseFirstMatchingAmount(
+  text: string,
+  patterns: RegExp[],
+): number | null {
+  for (const pattern of patterns) {
+    const match = text.match(pattern);
+    if (!match?.[1]) continue;
+    const value = Number(match[1].replace(/,/g, ""));
+    if (Number.isFinite(value) && value >= 0) return value;
+  }
+  return null;
+}
+
+function parseDate(text: string): Date | null {
+  for (const pattern of DATE_PATTERNS) {
+    const match = text.match(pattern);
+    if (!match?.[1]) continue;
+    const parsed = new Date(match[1]);
+    if (!Number.isNaN(parsed.getTime())) return parsed;
+  }
+  return null;
+}
+
+function parseVendor(lines: string[]): string | null {
+  const candidate = lines.find((line) => line.trim().length >= 3);
+  return candidate?.trim().slice(0, 120) ?? null;
+}
+
+function parseLineItems(lines: string[]): ReceiptLineItem[] {
+  const items: ReceiptLineItem[] = [];
+
+  for (const [index, rawLine] of lines.entries()) {
+    const line = rawLine.replace(/\s+/g, " ").trim();
+    if (line.length < 5 || NON_ITEM_LINE.test(line)) continue;
+
+    const match = line.match(/^(.{2,}?)\s+\$?(-?[\d,]+\.\d{2})$/);
+    if (!match?.[1] || !match[2]) continue;
+
+    const amount = Number(match[2].replace(/,/g, ""));
+    const name = match[1]
+      .replace(/^\d+\s*[xX]\s+/, "")
+      .replace(/\s+\d+\s*[xX]\s*$/, "")
+      .trim();
+
+    if (!Number.isFinite(amount) || amount <= 0 || name.length < 2) continue;
+
+    items.push({
+      id: `${index}-${name.toLowerCase().replace(/[^a-z0-9]+/g, "-")}-${amount.toFixed(2)}`,
+      name: name.slice(0, 80),
+      amount,
+      rawLine,
+    });
+  }
+
+  return items.slice(0, 30);
+}
+
+export function parseReceiptText(text: string): ReceiptParseResult {
+  const normalized = text.replace(/\r/g, "\n").trim();
+  const rawLines = normalized
+    .split("\n")
+    .map((line) => line.trim())
+    .filter(Boolean);
+
+  return {
+    amount: parseAmount(normalized),
+    date: parseDate(normalized),
+    subtotal: parseFirstMatchingAmount(normalized, SUBTOTAL_PATTERNS),
+    tax: parseFirstMatchingAmount(normalized, TAX_PATTERNS),
+    vendor: parseVendor(rawLines),
+    items: parseLineItems(rawLines),
+    rawLines,
+  };
+}