ソートできるようにしました。page.tsx

畔塗画面の対象圃場一覧で、圃場 / 面積 / グループ / 品種 の各ヘッダーを押すと昇順・降順を切り替えられます。初期状態は 圃場名昇順 です。選択状態はそのまま維持されるので、並べ替えてもチェックが外れることはありません。

必要なら次に、ソートだけでなく検索欄も足せます。圃場数が多いなら検索もかなり効きます。

frontend/src/app/levee-work/page.tsx

@@ -2,7 +2,7 @@
 
 import { Suspense, useEffect, useMemo, useState } from 'react';
 import { useRouter, useSearchParams } from 'next/navigation';
-import { ChevronLeft, PencilLine, Plus, Save, Trash2 } from 'lucide-react';
+import { ArrowDown, ArrowUp, ChevronLeft, PencilLine, Plus, Save, Trash2 } from 'lucide-react';
 
 import Navbar from '@/components/Navbar';
 import { api } from '@/lib/api';
@@ -18,6 +18,9 @@ type FormState = {
   selectedFieldIds: Set<number>;
 };
 
+type SortKey = 'field_name' | 'field_area_tan' | 'group_name' | 'variety_name';
+type SortDirection = 'asc' | 'desc';
+
 const extractErrorMessage = (error: any) => {
   const data = error?.response?.data;
   if (!data) return '保存に失敗しました。';
@@ -64,6 +67,8 @@ function LeveeWorkPageContent() {
   const [saving, setSaving] = useState(false);
   const [error, setError] = useState<string | null>(null);
   const [openedFromQuery, setOpenedFromQuery] = useState(false);
+  const [sortKey, setSortKey] = useState<SortKey>('field_name');
+  const [sortDirection, setSortDirection] = useState<SortDirection>('asc');
 
   useEffect(() => {
     localStorage.setItem(YEAR_KEY, String(year));
@@ -173,10 +178,48 @@ function LeveeWorkPageContent() {
 
   const selectedCount = form?.selectedFieldIds.size ?? 0;
 
+  const sortedCandidates = useMemo(() => {
+    const rows = [...candidates];
+    rows.sort((a, b) => {
+      let result = 0;
+
+      if (sortKey === 'field_area_tan') {
+        result = Number(a.field_area_tan) - Number(b.field_area_tan);
+      } else {
+        result = (a[sortKey] || '').toString().localeCompare((b[sortKey] || '').toString(), 'ja');
+      }
+
+      if (result === 0) {
+        result = a.field_name.localeCompare(b.field_name, 'ja');
+      }
+
+      return sortDirection === 'asc' ? result : -result;
+    });
+    return rows;
+  }, [candidates, sortDirection, sortKey]);
+
   const selectedCandidates = useMemo(() => {
     if (!form) return [];
-    return candidates.filter((candidate) => form.selectedFieldIds.has(candidate.field_id));
-  }, [candidates, form]);
+    return sortedCandidates.filter((candidate) => form.selectedFieldIds.has(candidate.field_id));
+  }, [form, sortedCandidates]);
+
+  const handleSort = (nextKey: SortKey) => {
+    if (sortKey === nextKey) {
+      setSortDirection((current) => (current === 'asc' ? 'desc' : 'asc'));
+      return;
+    }
+    setSortKey(nextKey);
+    setSortDirection('asc');
+  };
+
+  const renderSortIcon = (key: SortKey) => {
+    if (sortKey !== key) return null;
+    return sortDirection === 'asc' ? (
+      <ArrowUp className="h-3.5 w-3.5" />
+    ) : (
+      <ArrowDown className="h-3.5 w-3.5" />
+    );
+  };
 
   const handleSave = async () => {
     if (!form) return;
@@ -377,14 +420,50 @@ function LeveeWorkPageContent() {
                         <thead className="bg-gray-50">
                           <tr>
                             <th className="px-4 py-3 text-left font-medium text-gray-700">選択</th>
-                            <th className="px-4 py-3 text-left font-medium text-gray-700">圃場</th>
-                            <th className="px-4 py-3 text-left font-medium text-gray-700">面積</th>
-                            <th className="px-4 py-3 text-left font-medium text-gray-700">グループ</th>
-                            <th className="px-4 py-3 text-left font-medium text-gray-700">品種</th>
+                            <th className="px-4 py-3 text-left font-medium text-gray-700">
+                              <button
+                                type="button"
+                                onClick={() => handleSort('field_name')}
+                                className="inline-flex items-center gap-1 hover:text-gray-900"
+                              >
+                                圃場
+                                {renderSortIcon('field_name')}
+                              </button>
+                            </th>
+                            <th className="px-4 py-3 text-left font-medium text-gray-700">
+                              <button
+                                type="button"
+                                onClick={() => handleSort('field_area_tan')}
+                                className="inline-flex items-center gap-1 hover:text-gray-900"
+                              >
+                                面積
+                                {renderSortIcon('field_area_tan')}
+                              </button>
+                            </th>
+                            <th className="px-4 py-3 text-left font-medium text-gray-700">
+                              <button
+                                type="button"
+                                onClick={() => handleSort('group_name')}
+                                className="inline-flex items-center gap-1 hover:text-gray-900"
+                              >
+                                グループ
+                                {renderSortIcon('group_name')}
+                              </button>
+                            </th>
+                            <th className="px-4 py-3 text-left font-medium text-gray-700">
+                              <button
+                                type="button"
+                                onClick={() => handleSort('variety_name')}
+                                className="inline-flex items-center gap-1 hover:text-gray-900"
+                              >
+                                品種
+                                {renderSortIcon('variety_name')}
+                              </button>
+                            </th>
                           </tr>
                         </thead>
                         <tbody className="divide-y divide-gray-100">
-                          {candidates.map((candidate) => {
+                          {sortedCandidates.map((candidate) => {
                             const checked = form.selectedFieldIds.has(candidate.field_id);
                             return (
                               <tr key={candidate.field_id} className={checked ? 'bg-amber-50/40' : ''}>