// Minimal RFC-4180-ish CSV parser: handles quoted fields, embedded commas/newlines,
// and "" as an escaped quote inside a quoted field. Good enough for admin-supplied
// spreadsheet exports without pulling in a dependency for it.
export function parseCsv(text: string): string[][] {
  const rows: string[][] = [];
  let row: string[] = [];
  let field = "";
  let inQuotes = false;
  const src = text.replace(/\r\n/g, "\n").replace(/\r/g, "\n");

  for (let i = 0; i < src.length; i++) {
    const char = src[i];
    if (inQuotes) {
      if (char === '"') {
        if (src[i + 1] === '"') {
          field += '"';
          i++;
        } else {
          inQuotes = false;
        }
      } else {
        field += char;
      }
    } else if (char === '"') {
      inQuotes = true;
    } else if (char === ",") {
      row.push(field);
      field = "";
    } else if (char === "\n") {
      row.push(field);
      rows.push(row);
      row = [];
      field = "";
    } else {
      field += char;
    }
  }
  if (field.length > 0 || row.length > 0) {
    row.push(field);
    rows.push(row);
  }
  return rows.filter((r) => r.some((cell) => cell.trim() !== ""));
}

export function csvRowsToObjects(rows: string[][]): Record<string, string>[] {
  if (rows.length === 0) return [];
  const headers = rows[0].map((h) => h.trim().toLowerCase());
  return rows.slice(1).map((row) => {
    const obj: Record<string, string> = {};
    headers.forEach((h, i) => (obj[h] = (row[i] ?? "").trim()));
    return obj;
  });
}