Add rice transplant planning feature

frontend/src/app/allocation/page.tsx

@@ -367,6 +367,34 @@ export default function AllocationPage() {
     }
   };
 
+  const handleUpdateCropSeedInventory = async (cropId: number, seedInventoryKg: string) => {
+    try {
+      const crop = crops.find((item) => item.id === cropId);
+      if (!crop) return;
+      await api.patch(`/plans/crops/${cropId}/`, {
+        seed_inventory_kg: seedInventoryKg,
+      });
+      await fetchData(true);
+    } catch (error) {
+      console.error('Failed to update crop seed inventory:', error);
+      alert('種もみ在庫の更新に失敗しました');
+    }
+  };
+
+  const handleUpdateVarietyDefaultBoxes = async (varietyId: number, defaultBoxes: string) => {
+    try {
+      const variety = crops.flatMap((crop) => crop.varieties).find((item) => item.id === varietyId);
+      if (!variety) return;
+      await api.patch(`/plans/varieties/${varietyId}/`, {
+        default_seedling_boxes_per_tan: defaultBoxes,
+      });
+      await fetchData(true);
+    } catch (error) {
+      console.error('Failed to update variety default boxes:', error);
+      alert('品種デフォルトの更新に失敗しました');
+    }
+  };
+
   const toggleFieldSelection = (fieldId: number) => {
     setSelectedFields((prev) => {
       const next = new Set(prev);
@@ -1029,18 +1057,34 @@ export default function AllocationPage() {
             </div>
 
             <div className="flex-1 overflow-y-auto p-4">
+              {managerCropId && (
+                <div className="mb-4 rounded-lg border border-amber-200 bg-amber-50 p-3">
+                  <p className="mb-2 text-xs font-semibold text-amber-800">田植え計画用設定</p>
+                  <CropSeedInventoryForm
+                    crop={crops.find((crop) => crop.id === managerCropId) || null}
+                    onSave={handleUpdateCropSeedInventory}
+                  />
+                </div>
+              )}
               {managerCropId && getVarietiesForCrop(managerCropId).length > 0 ? (
                 <ul className="space-y-2">
                   {getVarietiesForCrop(managerCropId).map((v) => (
-                    <li key={v.id} className="flex items-center justify-between p-2 rounded hover:bg-gray-50">
-                      <span className="text-sm text-gray-900">{v.name}</span>
-                      <button
-                        onClick={() => handleDeleteVariety(v.id, v.name)}
-                        className="text-red-400 hover:text-red-600 p-1"
-                        title="削除"
-                      >
-                        <Trash2 className="h-4 w-4" />
-                      </button>
+                    <li key={v.id} className="rounded border border-gray-200 p-3">
+                      <div className="mb-2 flex items-center justify-between">
+                        <span className="text-sm font-medium text-gray-900">{v.name}</span>
+                        <button
+                          onClick={() => handleDeleteVariety(v.id, v.name)}
+                          className="text-red-400 hover:text-red-600 p-1"
+                          title="削除"
+                        >
+                          <Trash2 className="h-4 w-4" />
+                        </button>
+                      </div>
+                      <VarietyDefaultBoxesForm
+                        varietyId={v.id}
+                        initialValue={v.default_seedling_boxes_per_tan}
+                        onSave={handleUpdateVarietyDefaultBoxes}
+                      />
                     </li>
                   ))}
                 </ul>
@@ -1105,3 +1149,90 @@ function VarietyAddForm({ cropId, onAdd }: { cropId: number | null; onAdd: (name
     </div>
   );
 }
+
+function CropSeedInventoryForm({
+  crop,
+  onSave,
+}: {
+  crop: Crop | null;
+  onSave: (cropId: number, seedInventoryKg: string) => Promise<void>;
+}) {
+  const [value, setValue] = useState(crop?.seed_inventory_kg ?? '0');
+  const [saving, setSaving] = useState(false);
+
+  useEffect(() => {
+    setValue(crop?.seed_inventory_kg ?? '0');
+  }, [crop?.id, crop?.seed_inventory_kg]);
+
+  const handleSave = async () => {
+    if (!crop) return;
+    setSaving(true);
+    await onSave(crop.id, value);
+    setSaving(false);
+  };
+
+  return (
+    <div className="flex items-end gap-2">
+      <div className="flex-1">
+        <label className="mb-1 block text-xs text-gray-600">種もみ在庫(kg)</label>
+        <input
+          value={value}
+          onChange={(e) => setValue(e.target.value)}
+          className="w-full rounded-md border border-gray-300 px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-green-500"
+          inputMode="decimal"
+        />
+      </div>
+      <button
+        onClick={handleSave}
+        disabled={!crop || saving}
+        className="rounded-md bg-green-600 px-3 py-2 text-sm text-white hover:bg-green-700 disabled:opacity-50"
+      >
+        保存
+      </button>
+    </div>
+  );
+}
+
+function VarietyDefaultBoxesForm({
+  varietyId,
+  initialValue,
+  onSave,
+}: {
+  varietyId: number;
+  initialValue: string;
+  onSave: (varietyId: number, defaultBoxes: string) => Promise<void>;
+}) {
+  const [value, setValue] = useState(initialValue);
+  const [saving, setSaving] = useState(false);
+
+  useEffect(() => {
+    setValue(initialValue);
+  }, [initialValue]);
+
+  const handleSave = async () => {
+    setSaving(true);
+    await onSave(varietyId, value);
+    setSaving(false);
+  };
+
+  return (
+    <div className="flex items-end gap-2">
+      <div className="flex-1">
+        <label className="mb-1 block text-xs text-gray-600">反当苗箱枚数デフォルト</label>
+        <input
+          value={value}
+          onChange={(e) => setValue(e.target.value)}
+          className="w-full rounded-md border border-gray-300 px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-green-500"
+          inputMode="decimal"
+        />
+      </div>
+      <button
+        onClick={handleSave}
+        disabled={saving}
+        className="rounded-md bg-green-600 px-3 py-2 text-sm text-white hover:bg-green-700 disabled:opacity-50"
+      >
+        保存
+      </button>
+    </div>
+  );
+}

frontend/src/app/rice-transplant/[id]/edit/page.tsx

@@ -0,0 +1,5 @@
+import RiceTransplantEditPage from '../../_components/RiceTransplantEditPage';
+
+export default function EditRiceTransplantPage({ params }: { params: { id: string } }) {
+  return <RiceTransplantEditPage planId={parseInt(params.id, 10)} />;
+}

frontend/src/app/rice-transplant/_components/RiceTransplantEditPage.tsx

@@ -0,0 +1,447 @@
+'use client';
+
+import { useEffect, useMemo, useState } from 'react';
+import { useRouter } from 'next/navigation';
+import { ChevronLeft, Save } from 'lucide-react';
+
+import Navbar from '@/components/Navbar';
+import { api } from '@/lib/api';
+import { Crop, Field, RiceTransplantPlan } from '@/types';
+
+type EntryInput = {
+  seedling_boxes_per_tan: string;
+  seed_grams_per_box: string;
+};
+
+type EntryMap = Record<number, EntryInput>;
+
+const currentYear = new Date().getFullYear();
+
+export default function RiceTransplantEditPage({ planId }: { planId?: number }) {
+  const router = useRouter();
+  const isNew = !planId;
+
+  const [name, setName] = useState('');
+  const [year, setYear] = useState(currentYear);
+  const [varietyId, setVarietyId] = useState<number | ''>('');
+  const [defaultSeedGramsPerBox, setDefaultSeedGramsPerBox] = useState('200');
+  const [notes, setNotes] = useState('');
+
+  const [crops, setCrops] = useState<Crop[]>([]);
+  const [allFields, setAllFields] = useState<Field[]>([]);
+  const [candidateFields, setCandidateFields] = useState<Field[]>([]);
+  const [selectedFields, setSelectedFields] = useState<Field[]>([]);
+  const [entries, setEntries] = useState<EntryMap>({});
+
+  const [loading, setLoading] = useState(!isNew);
+  const [saving, setSaving] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+
+  const years = Array.from({ length: 5 }, (_, i) => currentYear + 1 - i);
+
+  const getVariety = (id: number) =>
+    crops.flatMap((crop) => crop.varieties).find((variety) => variety.id === id);
+
+  const getSelectedCrop = () => {
+    if (!varietyId) return null;
+    return crops.find((crop) => crop.varieties.some((variety) => variety.id === varietyId)) ?? null;
+  };
+
+  const initializeEntry = (fieldId: number, nextDefaultSeedGramsPerBox = defaultSeedGramsPerBox) => {
+    const variety = varietyId ? getVariety(varietyId) : null;
+    const defaultBoxes = variety?.default_seedling_boxes_per_tan ?? '0';
+    return {
+      seedling_boxes_per_tan: String(defaultBoxes),
+      seed_grams_per_box: nextDefaultSeedGramsPerBox,
+    };
+  };
+
+  useEffect(() => {
+    const init = async () => {
+      setError(null);
+      try {
+        const [cropsRes, fieldsRes] = await Promise.all([
+          api.get('/plans/crops/'),
+          api.get('/fields/?ordering=display_order,id'),
+        ]);
+        setCrops(cropsRes.data);
+        setAllFields(fieldsRes.data);
+
+        if (!isNew && planId) {
+          const planRes = await api.get(`/plans/rice-transplant-plans/${planId}/`);
+          const plan: RiceTransplantPlan = planRes.data;
+          setName(plan.name);
+          setYear(plan.year);
+          setVarietyId(plan.variety);
+          setDefaultSeedGramsPerBox(plan.default_seed_grams_per_box);
+          setNotes(plan.notes);
+
+          const fieldIds = new Set(plan.entries.map((entry) => entry.field));
+          const planFields = fieldsRes.data.filter((field: Field) => fieldIds.has(field.id));
+          setSelectedFields(planFields);
+          setCandidateFields(planFields);
+          setEntries(
+            plan.entries.reduce((acc: EntryMap, entry) => {
+              acc[entry.field] = {
+                seedling_boxes_per_tan: String(entry.seedling_boxes_per_tan),
+                seed_grams_per_box: String(entry.seed_grams_per_box),
+              };
+              return acc;
+            }, {})
+          );
+        }
+      } catch (e) {
+        console.error(e);
+        setError('データの読み込みに失敗しました。');
+      } finally {
+        setLoading(false);
+      }
+    };
+    init();
+  }, [isNew, planId]);
+
+  useEffect(() => {
+    const fetchCandidates = async () => {
+      if (!varietyId || !year || (!isNew && loading)) return;
+      try {
+        const res = await api.get(`/plans/rice-transplant-plans/candidate_fields/?year=${year}&variety_id=${varietyId}`);
+        const nextCandidates: Field[] = res.data;
+        setCandidateFields(nextCandidates);
+        if (isNew) {
+          setSelectedFields(nextCandidates);
+          setEntries((prev) => {
+            const next = { ...prev };
+            nextCandidates.forEach((field) => {
+              if (!next[field.id]) {
+                next[field.id] = initializeEntry(field.id);
+              }
+            });
+            return next;
+          });
+        }
+      } catch (e) {
+        console.error(e);
+        setError('候補圃場の取得に失敗しました。');
+      }
+    };
+    fetchCandidates();
+  }, [varietyId, year, isNew, loading]);
+
+  const updateEntry = (fieldId: number, key: keyof EntryInput, value: string) => {
+    setEntries((prev) => ({
+      ...prev,
+      [fieldId]: {
+        ...(prev[fieldId] ?? initializeEntry(fieldId)),
+        [key]: value,
+      },
+    }));
+  };
+
+  const applyDefaultsToSelected = () => {
+    setEntries((prev) => {
+      const next = { ...prev };
+      selectedFields.forEach((field) => {
+        next[field.id] = initializeEntry(field.id, defaultSeedGramsPerBox);
+      });
+      return next;
+    });
+  };
+
+  const addField = (field: Field) => {
+    if (selectedFields.some((selected) => selected.id === field.id)) return;
+    setSelectedFields((prev) => [...prev, field]);
+    setEntries((prev) => ({
+      ...prev,
+      [field.id]: prev[field.id] ?? initializeEntry(field.id),
+    }));
+  };
+
+  const removeField = (fieldId: number) => {
+    setSelectedFields((prev) => prev.filter((field) => field.id !== fieldId));
+  };
+
+  const fieldRows = useMemo(
+    () => selectedFields.map((field) => ({ field, entry: entries[field.id] ?? initializeEntry(field.id) })),
+    [selectedFields, entries, varietyId, defaultSeedGramsPerBox]
+  );
+
+  const calculateBoxes = (field: Field, entry: EntryInput) => {
+    const areaTan = parseFloat(field.area_tan || '0');
+    const boxesPerTan = parseFloat(entry.seedling_boxes_per_tan || '0');
+    return areaTan * boxesPerTan;
+  };
+
+  const calculateSeedKg = (field: Field, entry: EntryInput) => {
+    const boxes = calculateBoxes(field, entry);
+    const gramsPerBox = parseFloat(entry.seed_grams_per_box || '0');
+    return (boxes * gramsPerBox) / 1000;
+  };
+
+  const totalBoxes = fieldRows.reduce((sum, row) => sum + calculateBoxes(row.field, row.entry), 0);
+  const totalSeedKg = fieldRows.reduce((sum, row) => sum + calculateSeedKg(row.field, row.entry), 0);
+  const cropSeedInventoryKg = parseFloat(getSelectedCrop()?.seed_inventory_kg ?? '0');
+  const remainingSeedKg = cropSeedInventoryKg - totalSeedKg;
+
+  const handleSave = async () => {
+    setError(null);
+    if (!name.trim()) {
+      setError('計画名を入力してください。');
+      return;
+    }
+    if (!varietyId) {
+      setError('品種を選択してください。');
+      return;
+    }
+    if (selectedFields.length === 0) {
+      setError('圃場を1つ以上選択してください。');
+      return;
+    }
+
+    const payload = {
+      name,
+      year,
+      variety: varietyId,
+      default_seed_grams_per_box: defaultSeedGramsPerBox,
+      notes,
+      entries: selectedFields.map((field) => ({
+        field_id: field.id,
+        seedling_boxes_per_tan: entries[field.id]?.seedling_boxes_per_tan ?? initializeEntry(field.id).seedling_boxes_per_tan,
+        seed_grams_per_box: entries[field.id]?.seed_grams_per_box ?? defaultSeedGramsPerBox,
+      })),
+    };
+
+    setSaving(true);
+    try {
+      if (isNew) {
+        await api.post('/plans/rice-transplant-plans/', payload);
+      } else {
+        await api.put(`/plans/rice-transplant-plans/${planId}/`, payload);
+      }
+      router.push('/rice-transplant');
+    } catch (e) {
+      console.error(e);
+      setError('保存に失敗しました。');
+    } finally {
+      setSaving(false);
+    }
+  };
+
+  const unselectedFields = (candidateFields.length > 0 ? candidateFields : allFields).filter(
+    (field) => !selectedFields.some((selected) => selected.id === field.id)
+  );
+
+  if (loading) {
+    return (
+      <div className="min-h-screen bg-gray-50">
+        <Navbar />
+        <div className="mx-auto max-w-6xl px-4 py-8 text-gray-500">読み込み中...</div>
+      </div>
+    );
+  }
+
+  return (
+    <div className="min-h-screen bg-gray-50">
+      <Navbar />
+      <div className="mx-auto max-w-6xl px-4 py-8">
+        <div className="mb-6 flex items-center justify-between">
+          <div className="flex items-center gap-3">
+            <button onClick={() => router.push('/rice-transplant')} className="text-gray-500 hover:text-gray-700">
+              <ChevronLeft className="h-5 w-5" />
+            </button>
+            <h1 className="text-2xl font-bold text-gray-800">
+              {isNew ? '田植え計画 新規作成' : '田植え計画 編集'}
+            </h1>
+          </div>
+          <button
+            onClick={handleSave}
+            disabled={saving}
+            className="flex items-center gap-2 rounded-lg bg-green-600 px-4 py-2 text-white hover:bg-green-700 disabled:cursor-not-allowed disabled:opacity-50"
+          >
+            <Save className="h-4 w-4" />
+            {saving ? '保存中...' : '保存'}
+          </button>
+        </div>
+
+        {error && (
+          <div className="mb-4 rounded-lg border border-red-300 bg-red-50 px-4 py-3 text-sm text-red-700">
+            {error}
+          </div>
+        )}
+
+        <div className="mb-4 grid gap-4 rounded-lg bg-white p-4 shadow md:grid-cols-2 xl:grid-cols-4">
+          <div>
+            <label className="mb-1 block text-xs font-medium text-gray-600">計画名</label>
+            <input
+              value={name}
+              onChange={(e) => setName(e.target.value)}
+              className="w-full rounded-lg border border-gray-300 px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-green-500"
+              placeholder="例: 2026年度 コシヒカリ 第1回"
+            />
+            <p className="mt-1 text-xs text-gray-500">同じ年度・同じ品種でも、第1回や播種日ごとに複数計画を作れます。</p>
+          </div>
+          <div>
+            <label className="mb-1 block text-xs font-medium text-gray-600">年度</label>
+            <select
+              value={year}
+              onChange={(e) => setYear(parseInt(e.target.value, 10))}
+              className="w-full rounded-lg border border-gray-300 px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-green-500"
+            >
+              {years.map((value) => (
+                <option key={value} value={value}>
+                  {value}年度
+                </option>
+              ))}
+            </select>
+          </div>
+          <div>
+            <label className="mb-1 block text-xs font-medium text-gray-600">品種</label>
+            <select
+              value={varietyId}
+              onChange={(e) => setVarietyId(e.target.value ? parseInt(e.target.value, 10) : '')}
+              className="w-full rounded-lg border border-gray-300 px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-green-500"
+            >
+              <option value="">選択してください</option>
+              {crops.map((crop) => (
+                <optgroup key={crop.id} label={crop.name}>
+                  {crop.varieties.map((variety) => (
+                    <option key={variety.id} value={variety.id}>
+                      {variety.name}
+                    </option>
+                  ))}
+                </optgroup>
+              ))}
+            </select>
+          </div>
+          <div>
+            <label className="mb-1 block text-xs font-medium text-gray-600">苗箱1枚あたり種もみ(g) デフォルト</label>
+            <input
+              value={defaultSeedGramsPerBox}
+              onChange={(e) => setDefaultSeedGramsPerBox(e.target.value)}
+              className="w-full rounded-lg border border-gray-300 px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-green-500"
+              inputMode="decimal"
+            />
+          </div>
+        </div>
+
+        <div className="mb-4 grid gap-4 md:grid-cols-[2fr,1fr]">
+          <div className="rounded-lg bg-white p-4 shadow">
+            <div className="mb-3 flex items-center justify-between">
+              <h2 className="text-sm font-semibold text-gray-800">対象圃場</h2>
+              <button
+                onClick={applyDefaultsToSelected}
+                className="rounded-md border border-gray-300 px-3 py-1.5 text-xs text-gray-700 hover:bg-gray-100"
+              >
+                初期値を一括反映
+              </button>
+            </div>
+            <div className="mb-3 flex flex-wrap gap-2">
+              {selectedFields.map((field) => (
+                <button
+                  key={field.id}
+                  onClick={() => removeField(field.id)}
+                  className="rounded-full border border-green-200 bg-green-50 px-3 py-1 text-xs text-green-800"
+                >
+                  {field.name} ×
+                </button>
+              ))}
+              {selectedFields.length === 0 && <p className="text-sm text-gray-500">圃場が選択されていません。</p>}
+            </div>
+            {unselectedFields.length > 0 && (
+              <div>
+                <p className="mb-2 text-xs font-medium text-gray-500">追加可能</p>
+                <div className="flex flex-wrap gap-2">
+                  {unselectedFields.map((field) => (
+                    <button
+                      key={field.id}
+                      onClick={() => addField(field)}
+                      className="rounded-full border border-gray-200 bg-gray-50 px-3 py-1 text-xs text-gray-700 hover:bg-gray-100"
+                    >
+                      {field.name}
+                    </button>
+                  ))}
+                </div>
+              </div>
+            )}
+          </div>
+
+          <div className="rounded-lg bg-white p-4 shadow">
+            <h2 className="mb-3 text-sm font-semibold text-gray-800">集計</h2>
+            <div className="space-y-2 text-sm">
+              <div className="flex justify-between text-gray-600">
+                <span>対象圃場</span>
+                <span>{selectedFields.length}筆</span>
+              </div>
+              <div className="flex justify-between text-gray-600">
+                <span>苗箱合計</span>
+                <span>{totalBoxes.toFixed(2)}枚</span>
+              </div>
+              <div className="flex justify-between text-gray-600">
+                <span>種もみ計画</span>
+                <span>{totalSeedKg.toFixed(3)}kg</span>
+              </div>
+              <div className="flex justify-between text-gray-600">
+                <span>{getSelectedCrop()?.name ?? '作物'} 在庫</span>
+                <span>{cropSeedInventoryKg.toFixed(3)}kg</span>
+              </div>
+              <div className={`flex justify-between font-semibold ${remainingSeedKg < 0 ? 'text-red-600' : 'text-emerald-700'}`}>
+                <span>残在庫見込み</span>
+                <span>{remainingSeedKg.toFixed(3)}kg</span>
+              </div>
+            </div>
+          </div>
+        </div>
+
+        <div className="mb-4 rounded-lg bg-white p-4 shadow">
+          <label className="mb-1 block text-xs font-medium text-gray-600">備考</label>
+          <textarea
+            value={notes}
+            onChange={(e) => setNotes(e.target.value)}
+            rows={3}
+            className="w-full rounded-lg border border-gray-300 px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-green-500"
+          />
+        </div>
+
+        <div className="overflow-hidden rounded-lg bg-white shadow">
+          <table className="w-full text-sm">
+            <thead className="border-b bg-gray-50">
+              <tr>
+                <th className="px-4 py-3 text-left font-medium text-gray-700">圃場</th>
+                <th className="px-4 py-3 text-right font-medium text-gray-700">面積(反)</th>
+                <th className="px-4 py-3 text-right font-medium text-gray-700">反当苗箱枚数</th>
+                <th className="px-4 py-3 text-right font-medium text-gray-700">種もみg/箱</th>
+                <th className="px-4 py-3 text-right font-medium text-gray-700">苗箱合計</th>
+                <th className="px-4 py-3 text-right font-medium text-gray-700">種もみkg</th>
+              </tr>
+            </thead>
+            <tbody className="divide-y divide-gray-100">
+              {fieldRows.map(({ field, entry }) => (
+                <tr key={field.id} className="hover:bg-gray-50">
+                  <td className="px-4 py-3 font-medium text-gray-900">{field.name}</td>
+                  <td className="px-4 py-3 text-right tabular-nums text-gray-600">{field.area_tan}</td>
+                  <td className="px-4 py-3">
+                    <input
+                      value={entry.seedling_boxes_per_tan}
+                      onChange={(e) => updateEntry(field.id, 'seedling_boxes_per_tan', e.target.value)}
+                      className="w-24 rounded-md border border-gray-300 px-2 py-1 text-right focus:outline-none focus:ring-2 focus:ring-green-500"
+                      inputMode="decimal"
+                    />
+                  </td>
+                  <td className="px-4 py-3">
+                    <input
+                      value={entry.seed_grams_per_box}
+                      onChange={(e) => updateEntry(field.id, 'seed_grams_per_box', e.target.value)}
+                      className="w-24 rounded-md border border-gray-300 px-2 py-1 text-right focus:outline-none focus:ring-2 focus:ring-green-500"
+                      inputMode="decimal"
+                    />
+                  </td>
+                  <td className="px-4 py-3 text-right tabular-nums text-gray-700">{calculateBoxes(field, entry).toFixed(2)}</td>
+                  <td className="px-4 py-3 text-right tabular-nums text-gray-700">{calculateSeedKg(field, entry).toFixed(3)}</td>
+                </tr>
+              ))}
+            </tbody>
+          </table>
+        </div>
+      </div>
+    </div>
+  );
+}

frontend/src/app/rice-transplant/new/page.tsx

@@ -0,0 +1,5 @@
+import RiceTransplantEditPage from '../_components/RiceTransplantEditPage';
+
+export default function NewRiceTransplantPage() {
+  return <RiceTransplantEditPage />;
+}

frontend/src/app/rice-transplant/page.tsx

@@ -0,0 +1,159 @@
+'use client';
+
+import { useEffect, useState } from 'react';
+import { useRouter } from 'next/navigation';
+import { Pencil, Plus, Sprout, Trash2 } from 'lucide-react';
+
+import Navbar from '@/components/Navbar';
+import { api } from '@/lib/api';
+import { RiceTransplantPlan } from '@/types';
+
+const currentYear = new Date().getFullYear();
+
+export default function RiceTransplantPage() {
+  const router = useRouter();
+  const [year, setYear] = useState<number>(() => {
+    if (typeof window !== 'undefined') {
+      const saved = localStorage.getItem('riceTransplantYear');
+      if (saved) return parseInt(saved, 10);
+    }
+    return currentYear;
+  });
+  const [plans, setPlans] = useState<RiceTransplantPlan[]>([]);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState<string | null>(null);
+
+  const years = Array.from({ length: 5 }, (_, i) => currentYear + 1 - i);
+
+  const fetchPlans = async () => {
+    setLoading(true);
+    setError(null);
+    try {
+      const res = await api.get(`/plans/rice-transplant-plans/?year=${year}`);
+      setPlans(res.data);
+    } catch (e) {
+      console.error(e);
+      setError('田植え計画の読み込みに失敗しました。');
+    } finally {
+      setLoading(false);
+    }
+  };
+
+  useEffect(() => {
+    localStorage.setItem('riceTransplantYear', String(year));
+    fetchPlans();
+  }, [year]);
+
+  const handleDelete = async (id: number, name: string) => {
+    setError(null);
+    if (!confirm(`「${name}」を削除しますか？`)) {
+      return;
+    }
+    try {
+      await api.delete(`/plans/rice-transplant-plans/${id}/`);
+      await fetchPlans();
+    } catch (e) {
+      console.error(e);
+      setError(`「${name}」の削除に失敗しました。`);
+    }
+  };
+
+  return (
+    <div className="min-h-screen bg-gray-50">
+      <Navbar />
+      <div className="mx-auto max-w-6xl px-4 py-8">
+        <div className="mb-6 flex items-center justify-between">
+          <div className="flex items-center gap-3">
+            <Sprout className="h-6 w-6 text-emerald-600" />
+            <h1 className="text-2xl font-bold text-gray-800">田植え計画</h1>
+          </div>
+          <button
+            onClick={() => router.push('/rice-transplant/new')}
+            className="flex items-center gap-2 rounded-lg bg-emerald-600 px-4 py-2 text-white hover:bg-emerald-700"
+          >
+            <Plus className="h-4 w-4" />
+            新規作成
+          </button>
+        </div>
+
+        <div className="mb-6 flex items-center gap-3">
+          <label className="text-sm font-medium text-gray-700">年度:</label>
+          <select
+            value={year}
+            onChange={(e) => setYear(parseInt(e.target.value, 10))}
+            className="rounded-lg border border-gray-300 px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-emerald-500"
+          >
+            {years.map((value) => (
+              <option key={value} value={value}>
+                {value}年度
+              </option>
+            ))}
+          </select>
+        </div>
+
+        {error && (
+          <div className="mb-4 rounded-lg border border-red-300 bg-red-50 px-4 py-3 text-sm text-red-700">
+            {error}
+          </div>
+        )}
+
+        {loading ? (
+          <p className="text-gray-500">読み込み中...</p>
+        ) : plans.length === 0 ? (
+          <div className="rounded-lg bg-white p-12 text-center text-gray-400 shadow">
+            <Sprout className="mx-auto mb-3 h-12 w-12 opacity-30" />
+            <p>{year}年度の田植え計画はありません</p>
+          </div>
+        ) : (
+          <div className="overflow-hidden rounded-lg bg-white shadow">
+            <table className="w-full text-sm">
+              <thead className="border-b bg-gray-50">
+                <tr>
+                  <th className="px-4 py-3 text-left font-medium text-gray-700">計画名</th>
+                  <th className="px-4 py-3 text-left font-medium text-gray-700">作物 / 品種</th>
+                  <th className="px-4 py-3 text-right font-medium text-gray-700">圃場</th>
+                  <th className="px-4 py-3 text-right font-medium text-gray-700">苗箱合計</th>
+                  <th className="px-4 py-3 text-right font-medium text-gray-700">種もみ計画</th>
+                  <th className="px-4 py-3 text-right font-medium text-gray-700">残在庫見込み</th>
+                  <th className="px-4 py-3" />
+                </tr>
+              </thead>
+              <tbody className="divide-y divide-gray-100">
+                {plans.map((plan) => (
+                  <tr key={plan.id} className="hover:bg-gray-50">
+                    <td className="px-4 py-3 font-medium text-gray-900">{plan.name}</td>
+                    <td className="px-4 py-3 text-gray-600">{plan.crop_name} / {plan.variety_name}</td>
+                    <td className="px-4 py-3 text-right text-gray-600">{plan.field_count}筆</td>
+                    <td className="px-4 py-3 text-right tabular-nums text-gray-600">{plan.total_seedling_boxes}</td>
+                    <td className="px-4 py-3 text-right tabular-nums text-gray-600">{plan.total_seed_kg}kg</td>
+                    <td className={`px-4 py-3 text-right tabular-nums ${parseFloat(plan.remaining_seed_kg) < 0 ? 'text-red-600' : 'text-emerald-700'}`}>
+                      {plan.remaining_seed_kg}kg
+                    </td>
+                    <td className="px-4 py-3">
+                      <div className="flex items-center justify-end gap-2">
+                        <button
+                          onClick={() => router.push(`/rice-transplant/${plan.id}/edit`)}
+                          className="flex items-center gap-1 rounded border border-blue-300 px-2.5 py-1.5 text-xs text-blue-700 hover:bg-blue-50"
+                        >
+                          <Pencil className="h-3.5 w-3.5" />
+                          編集
+                        </button>
+                        <button
+                          onClick={() => handleDelete(plan.id, plan.name)}
+                          className="flex items-center gap-1 rounded border border-red-300 px-2.5 py-1.5 text-xs text-red-600 hover:bg-red-50"
+                        >
+                          <Trash2 className="h-3.5 w-3.5" />
+                          削除
+                        </button>
+                      </div>
+                    </td>
+                  </tr>
+                ))}
+              </tbody>
+            </table>
+          </div>
+        )}
+      </div>
+    </div>
+  );
+}

frontend/src/components/Navbar.tsx

@@ -1,7 +1,7 @@
 'use client';
 
 import { useRouter, usePathname } from 'next/navigation';
-import { LogOut, Wheat, MapPin, FileText, Upload, LayoutDashboard, History, Shield, KeyRound, Cloud, Sprout, FlaskConical, Package, NotebookText, PencilLine, Construction } from 'lucide-react';
+import { LogOut, Wheat, MapPin, FileText, Upload, LayoutDashboard, History, Shield, KeyRound, Cloud, Sprout, FlaskConical, Package, NotebookText, PencilLine, Construction, Tractor } from 'lucide-react';
 import { logout } from '@/lib/api';
 
 export default function Navbar() {
@@ -122,6 +122,17 @@ export default function Navbar() {
                 <Sprout className="h-4 w-4 mr-2" />
                 施肥計画
               </button>
+              <button
+                onClick={() => router.push('/rice-transplant')}
+                className={`flex items-center px-3 py-2 text-sm rounded-md transition-colors ${
+                  pathname?.startsWith('/rice-transplant')
+                    ? 'text-green-700 bg-green-50'
+                    : 'text-gray-700 hover:text-gray-900 hover:bg-gray-100'
+                }`}
+              >
+                <Tractor className="h-4 w-4 mr-2" />
+                田植え計画
+              </button>
               <button
                 onClick={() => router.push('/fertilizer/spreading')}
                 className={`flex items-center px-3 py-2 text-sm rounded-md transition-colors ${

frontend/src/types/index.ts

@@ -36,11 +36,13 @@ export interface Variety {
   id: number;
   crop: number;
   name: string;
+  default_seedling_boxes_per_tan: string;
 }
 
 export interface Crop {
   id: number;
   name: string;
+  seed_inventory_kg: string;
   varieties: Variety[];
 }
 
@@ -165,6 +167,36 @@ export interface FertilizationPlan {
   updated_at: string;
 }
 
+export interface RiceTransplantEntry {
+  id?: number;
+  field: number;
+  field_name?: string;
+  field_area_tan?: string;
+  seedling_boxes_per_tan: string;
+  seed_grams_per_box: string;
+  planned_boxes: string;
+  planned_seed_kg: string;
+}
+
+export interface RiceTransplantPlan {
+  id: number;
+  name: string;
+  year: number;
+  variety: number;
+  variety_name: string;
+  crop_name: string;
+  default_seed_grams_per_box: string;
+  notes: string;
+  entries: RiceTransplantEntry[];
+  field_count: number;
+  total_seedling_boxes: string;
+  total_seed_kg: string;
+  crop_seed_inventory_kg: string;
+  remaining_seed_kg: string;
+  created_at: string;
+  updated_at: string;
+}
+
 export interface DeliveryGroupField {
   id: number;
   name: string;