/**
 * 将数据导出为 CSV 文件并触发浏览器下载。
 *
 * @param filename 下载文件名（如 "users.csv"）
 * @param columns  列定义，每项包含 key（数据字段名）和 label（表头）
 * @param data     要导出的数据行
 */
export function exportToCsv<T extends Record<string, unknown>>(
  filename: string,
  columns: ReadonlyArray<{ key: keyof T & string; label: string }>,
  data: ReadonlyArray<T>
): void {
  const escape = (value: unknown): string => {
    const str = value === null || value === undefined ? "" : String(value)
    if (str.includes(",") || str.includes('"') || str.includes("\n")) {
      return `"${str.replace(/"/g, '""')}"`
    }
    return str
  }

  const header = columns.map((col) => escape(col.label)).join(",")
  const rows = data.map((row) =>
    columns.map((col) => escape(row[col.key])).join(",")
  )

  const csv = [header, ...rows].join("\n")
  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
  link.click()
  URL.revokeObjectURL(url)
}