export type CsvColumn<T> = {
  title: string;
  value: (row: T) => unknown;
};

function csvCell(value: unknown) {
  if (value == null) return '';
  const text = typeof value === 'object' ? JSON.stringify(value) : String(value);
  return `"${text.replace(/"/g, '""')}"`;
}

export function buildCsv<T>(columns: CsvColumn<T>[], rows: T[]) {
  return [
    columns.map((item) => csvCell(item.title)).join(','),
    ...rows.map((row) => columns.map((column) => csvCell(column.value(row))).join(','))
  ].join('\n');
}

export function downloadCsv(filename: string, csv: string) {
  const blob = new Blob(['\uFEFF', csv], { type: 'text/csv;charset=utf-8' });
  const url = URL.createObjectURL(blob);
  const link = document.createElement('a');
  link.href = url;
  link.download = filename;
  document.body.appendChild(link);
  link.click();
  link.remove();
  URL.revokeObjectURL(url);
}