feat: add word import and class type display controls

lib/word-excel.ts

@@ -0,0 +1,57 @@
+import * as XLSX from "xlsx";
+import type { WordImportInput, WordRecord } from "@/lib/db";
+
+export const wordExcelHeaders = ["词库英语", "中文", "图标/图片"] as const;
+
+type WordExcelHeader = (typeof wordExcelHeaders)[number];
+
+type WordExcelRow = Record<WordExcelHeader, string>;
+
+export function parseWordExcel(buffer: Buffer): WordImportInput[] {
+  const workbook = XLSX.read(buffer, { type: "buffer" });
+  const sheetName = workbook.SheetNames[0];
+  if (!sheetName) {
+    throw new Error("表格中没有可导入的工作表");
+  }
+
+  const sheet = workbook.Sheets[sheetName];
+  const rows = XLSX.utils.sheet_to_json<Record<string, unknown>>(sheet, {
+    defval: "",
+    raw: false,
+  });
+
+  return rows.map((row) => ({
+    english: readCell(row, "词库英语"),
+    chinese: readCell(row, "中文"),
+    image: readCell(row, "图标/图片"),
+  }));
+}
+
+export function buildWordExcel(words: WordRecord[]) {
+  const rows: WordExcelRow[] =
+    words.length > 0
+      ? words.map((word) => ({
+          词库英语: word.english,
+          中文: word.chinese,
+          "图标/图片": word.image,
+        }))
+      : [
+          {
+            词库英语: "apple",
+            中文: "苹果",
+            "图标/图片": "🍎",
+          },
+        ];
+
+  const worksheet = XLSX.utils.json_to_sheet(rows, { header: [...wordExcelHeaders] });
+  worksheet["!cols"] = [{ wch: 24 }, { wch: 18 }, { wch: 28 }];
+
+  const workbook = XLSX.utils.book_new();
+  XLSX.utils.book_append_sheet(workbook, worksheet, "词库导入");
+  return XLSX.write(workbook, { bookType: "xlsx", type: "buffer" }) as Buffer;
+}
+
+function readCell(row: Record<string, unknown>, header: string) {
+  const value = row[header];
+  return value == null ? "" : String(value).trim();
+}