feat: 풀스택 할일관리 앱 구현 (통합 모달 + 간트차트)

- Backend: FastAPI + MongoDB + Redis (카테고리, 할일 CRUD, 파일 첨부, 검색, 대시보드)
- Frontend: Next.js 15 + Tailwind + React Query + Zustand
- 통합 TodoModal: 생성/수정 모달 통합, 탭 구조 (기본/태그와 첨부)
- 간트차트: 카테고리별 할일 타임라인 시각화
- TodoCard: 제목/카테고리/우선순위/태그/첨부 한줄 표시
- Docker Compose 배포 (Frontend:3010, Backend:8010, MongoDB:27021, Redis:6391)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/app/services/dashboard_service.py

@@ -0,0 +1,182 @@
+import json
+from datetime import datetime, timezone
+
+from bson import ObjectId
+from motor.motor_asyncio import AsyncIOMotorDatabase
+import redis.asyncio as aioredis
+
+from app.models.todo import (
+    DashboardStats,
+    OverviewStats,
+    CategoryStats,
+    PriorityStats,
+    UpcomingDeadline,
+)
+
+DASHBOARD_CACHE_KEY = "dashboard:stats"
+DASHBOARD_CACHE_TTL = 60  # 60초
+
+
+class DashboardService:
+    """대시보드 통계 + Redis 캐싱"""
+
+    def __init__(self, db: AsyncIOMotorDatabase, redis_client: aioredis.Redis):
+        self.todos = db["todos"]
+        self.categories = db["categories"]
+        self.redis = redis_client
+
+    async def get_stats(self) -> DashboardStats:
+        """F-018: 대시보드 통계
+        1. Redis 캐시 확인
+        2. 캐시 히트 -> JSON 파싱 후 반환
+        3. 캐시 미스 -> MongoDB 집계 -> Redis 저장 (TTL 60s) -> 반환
+        """
+        # Redis 캐시 확인
+        try:
+            cached = await self.redis.get(DASHBOARD_CACHE_KEY)
+            if cached:
+                data = json.loads(cached)
+                return DashboardStats(**data)
+        except Exception:
+            pass  # Redis 에러 시 DB에서 직접 조회
+
+        # 캐시 미스: MongoDB 집계
+        stats = await self._compute_stats()
+
+        # Redis에 캐싱
+        try:
+            stats_json = stats.model_dump_json()
+            await self.redis.setex(DASHBOARD_CACHE_KEY, DASHBOARD_CACHE_TTL, stats_json)
+        except Exception:
+            pass  # Redis 저장 실패는 무시
+
+        return stats
+
+    async def _compute_stats(self) -> DashboardStats:
+        """MongoDB 집계 파이프라인으로 통계 계산"""
+        # 1. Overview (전체/완료/미완료/완료율)
+        total = await self.todos.count_documents({})
+        completed = await self.todos.count_documents({"completed": True})
+        incomplete = total - completed
+        completion_rate = round((completed / total * 100), 1) if total > 0 else 0.0
+
+        overview = OverviewStats(
+            total=total,
+            completed=completed,
+            incomplete=incomplete,
+            completion_rate=completion_rate,
+        )
+
+        # 2. By Category (카테고리별 할일 분포)
+        by_category = await self._compute_by_category()
+
+        # 3. By Priority (우선순위별 현황)
+        by_priority = await self._compute_by_priority()
+
+        # 4. Upcoming Deadlines (마감 임박 할일 상위 5개)
+        upcoming_deadlines = await self._compute_upcoming_deadlines()
+
+        return DashboardStats(
+            overview=overview,
+            by_category=by_category,
+            by_priority=by_priority,
+            upcoming_deadlines=upcoming_deadlines,
+        )
+
+    async def _compute_by_category(self) -> list[CategoryStats]:
+        """카테고리별 할일 분포 집계"""
+        pipeline = [
+            {"$group": {
+                "_id": "$category_id",
+                "count": {"$sum": 1},
+            }},
+            {"$sort": {"count": -1}},
+        ]
+
+        results = await self.todos.aggregate(pipeline).to_list(None)
+
+        # 카테고리 정보 조회
+        cat_ids = set()
+        for r in results:
+            if r["_id"]:
+                try:
+                    cat_ids.add(ObjectId(r["_id"]))
+                except Exception:
+                    pass
+
+        cat_map: dict[str, dict] = {}
+        if cat_ids:
+            async for cat in self.categories.find({"_id": {"$in": list(cat_ids)}}):
+                cat_map[str(cat["_id"])] = cat
+
+        category_stats = []
+        for r in results:
+            cat_id = r["_id"]
+            if cat_id and cat_id in cat_map:
+                cat = cat_map[cat_id]
+                category_stats.append(CategoryStats(
+                    category_id=cat_id,
+                    name=cat["name"],
+                    color=cat.get("color", "#6B7280"),
+                    count=r["count"],
+                ))
+            else:
+                category_stats.append(CategoryStats(
+                    category_id=None,
+                    name="미분류",
+                    color="#9CA3AF",
+                    count=r["count"],
+                ))
+
+        return category_stats
+
+    async def _compute_by_priority(self) -> PriorityStats:
+        """우선순위별 현황 집계"""
+        pipeline = [
+            {"$group": {
+                "_id": "$priority",
+                "count": {"$sum": 1},
+            }},
+        ]
+
+        results = await self.todos.aggregate(pipeline).to_list(None)
+
+        priority_map = {"high": 0, "medium": 0, "low": 0}
+        for r in results:
+            if r["_id"] in priority_map:
+                priority_map[r["_id"]] = r["count"]
+
+        return PriorityStats(
+            high=priority_map["high"],
+            medium=priority_map["medium"],
+            low=priority_map["low"],
+        )
+
+    async def _compute_upcoming_deadlines(self) -> list[UpcomingDeadline]:
+        """마감 임박 할일 상위 5개 (미완료, 마감일 있는 것, 마감일 오름차순)"""
+        now = datetime.now(timezone.utc)
+
+        cursor = self.todos.find({
+            "completed": False,
+            "due_date": {"$ne": None, "$gte": now},
+        }).sort("due_date", 1).limit(5)
+
+        docs = await cursor.to_list(5)
+
+        deadlines = []
+        for doc in docs:
+            deadlines.append(UpcomingDeadline(
+                id=str(doc["_id"]),
+                title=doc["title"],
+                due_date=doc["due_date"],
+                priority=doc["priority"],
+            ))
+
+        return deadlines
+
+    async def invalidate_cache(self) -> None:
+        """캐시 무효화: 할일 CUD 작업 후 호출"""
+        try:
+            await self.redis.delete(DASHBOARD_CACHE_KEY)
+        except Exception:
+            pass