feat: 购油方案 — 会员请求+老师定制+购油清单

后端:
- oil_plans/oil_plan_recipes 表
- 7个API: teachers列表、方案CRUD、配方增删、购油清单计算
- 购油清单自动算月消耗、瓶数、费用，交叉比对库存

前端:
- 会员端(库存页): 请求方案→选老师→描述需求；查看购油清单
- 老师端(用户管理): 接收请求→选配方+频率→激活方案
- plans store 管理状态

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/main.py

@@ -1583,6 +1583,191 @@ def recipes_by_inventory(user=Depends(get_current_user)):
     return result
 
 
+# ── Oil Plans (purchase plans) ─────────────────────────
+@app.get("/api/teachers")
+def list_teachers(user=Depends(get_current_user)):
+    conn = get_db()
+    rows = conn.execute(
+        "SELECT id, display_name, username FROM users WHERE role IN ('senior_editor', 'admin') ORDER BY id"
+    ).fetchall()
+    conn.close()
+    return [{"id": r["id"], "display_name": r["display_name"] or r["username"], "username": r["username"]} for r in rows]
+
+
+@app.get("/api/oil-plans")
+def list_oil_plans(user=Depends(get_current_user)):
+    if not user.get("id"):
+        return []
+    conn = get_db()
+    if user["role"] in ("senior_editor", "admin"):
+        plans = conn.execute(
+            "SELECT p.*, u.display_name as user_name, u.username "
+            "FROM oil_plans p LEFT JOIN users u ON p.user_id = u.id "
+            "WHERE p.teacher_id = ? OR p.user_id = ? ORDER BY p.created_at DESC",
+            (user["id"], user["id"])
+        ).fetchall()
+    else:
+        plans = conn.execute(
+            "SELECT p.*, u.display_name as teacher_name "
+            "FROM oil_plans p LEFT JOIN users u ON p.teacher_id = u.id "
+            "WHERE p.user_id = ? ORDER BY p.created_at DESC", (user["id"],)
+        ).fetchall()
+    result = []
+    for p in plans:
+        d = dict(p)
+        recipes = conn.execute(
+            "SELECT id, recipe_name, ingredients, times_per_month FROM oil_plan_recipes WHERE plan_id = ?",
+            (p["id"],)
+        ).fetchall()
+        d["recipes"] = [{"id": r["id"], "recipe_name": r["recipe_name"],
+                         "ingredients": json.loads(r["ingredients"]), "times_per_month": r["times_per_month"]} for r in recipes]
+        result.append(d)
+    conn.close()
+    return result
+
+
+@app.post("/api/oil-plans", status_code=201)
+def create_oil_plan(body: dict, user=Depends(get_current_user)):
+    if not user.get("id"):
+        raise HTTPException(403, "请先登录")
+    health_desc = body.get("health_desc", "").strip()
+    teacher_id = body.get("teacher_id")
+    # Teacher/admin can create plan for a user directly
+    target_user_id = body.get("user_id") if user["role"] in ("senior_editor", "admin") else None
+    if not teacher_id:
+        raise HTTPException(400, "请选择老师")
+    conn = get_db()
+    c = conn.cursor()
+    plan_user_id = target_user_id or user["id"]
+    c.execute("INSERT INTO oil_plans (user_id, teacher_id, health_desc) VALUES (?, ?, ?)",
+              (plan_user_id, teacher_id, health_desc))
+    plan_id = c.lastrowid
+    who = user.get("display_name") or user["username"]
+    conn.execute(
+        "INSERT INTO notifications (target_role, title, body, target_user_id) VALUES (?, ?, ?, ?)",
+        ("admin", "📋 新方案请求", f"{who}：{health_desc[:50]}", teacher_id)
+    )
+    conn.commit()
+    conn.close()
+    return {"id": plan_id}
+
+
+@app.put("/api/oil-plans/{plan_id}")
+def update_oil_plan(plan_id: int, body: dict, user=Depends(get_current_user)):
+    conn = get_db()
+    plan = conn.execute("SELECT * FROM oil_plans WHERE id = ?", (plan_id,)).fetchone()
+    if not plan:
+        conn.close()
+        raise HTTPException(404, "方案不存在")
+    if plan["teacher_id"] != user["id"] and user["role"] != "admin":
+        conn.close()
+        raise HTTPException(403, "无权操作")
+    if "title" in body:
+        conn.execute("UPDATE oil_plans SET title = ? WHERE id = ?", (body["title"], plan_id))
+    if "status" in body:
+        old_status = plan["status"]
+        conn.execute("UPDATE oil_plans SET status = ? WHERE id = ?", (body["status"], plan_id))
+        if body["status"] == "active" and old_status != "active":
+            teacher_name = user.get("display_name") or user["username"]
+            conn.execute(
+                "INSERT INTO notifications (target_role, title, body, target_user_id) VALUES (?, ?, ?, ?)",
+                ("viewer", "🎉 你的购油方案已就绪", f"{teacher_name}老师已为你定制好方案，去库存页查看！", plan["user_id"])
+            )
+    conn.commit()
+    conn.close()
+    return {"ok": True}
+
+
+@app.post("/api/oil-plans/{plan_id}/recipes", status_code=201)
+def add_plan_recipe(plan_id: int, body: dict, user=Depends(get_current_user)):
+    conn = get_db()
+    plan = conn.execute("SELECT * FROM oil_plans WHERE id = ?", (plan_id,)).fetchone()
+    if not plan:
+        conn.close()
+        raise HTTPException(404, "方案不存在")
+    if plan["teacher_id"] != user["id"] and user["role"] != "admin":
+        conn.close()
+        raise HTTPException(403, "无权操作")
+    recipe_name = body.get("recipe_name", "").strip()
+    ingredients = body.get("ingredients", [])
+    times = body.get("times_per_month", 1)
+    if not recipe_name or not ingredients:
+        conn.close()
+        raise HTTPException(400, "配方名和成分不能为空")
+    c = conn.cursor()
+    c.execute("INSERT INTO oil_plan_recipes (plan_id, recipe_name, ingredients, times_per_month) VALUES (?, ?, ?, ?)",
+              (plan_id, recipe_name, json.dumps(ingredients, ensure_ascii=False), times))
+    conn.commit()
+    rid = c.lastrowid
+    conn.close()
+    return {"id": rid}
+
+
+@app.delete("/api/oil-plans/{plan_id}/recipes/{recipe_id}")
+def remove_plan_recipe(plan_id: int, recipe_id: int, user=Depends(get_current_user)):
+    conn = get_db()
+    plan = conn.execute("SELECT * FROM oil_plans WHERE id = ?", (plan_id,)).fetchone()
+    if not plan:
+        conn.close()
+        raise HTTPException(404)
+    if plan["teacher_id"] != user["id"] and user["role"] != "admin":
+        conn.close()
+        raise HTTPException(403)
+    conn.execute("DELETE FROM oil_plan_recipes WHERE id = ? AND plan_id = ?", (recipe_id, plan_id))
+    conn.commit()
+    conn.close()
+    return {"ok": True}
+
+
+@app.get("/api/oil-plans/{plan_id}/shopping-list")
+def plan_shopping_list(plan_id: int, user=Depends(get_current_user)):
+    if not user.get("id"):
+        raise HTTPException(403, "请先登录")
+    conn = get_db()
+    plan = conn.execute("SELECT * FROM oil_plans WHERE id = ?", (plan_id,)).fetchone()
+    if not plan:
+        conn.close()
+        raise HTTPException(404)
+    if plan["user_id"] != user["id"] and plan["teacher_id"] != user["id"] and user["role"] != "admin":
+        conn.close()
+        raise HTTPException(403)
+    recipes = conn.execute("SELECT * FROM oil_plan_recipes WHERE plan_id = ?", (plan_id,)).fetchall()
+    # Calculate monthly drops per oil
+    oil_drops = {}
+    for r in recipes:
+        ings = json.loads(r["ingredients"])
+        for ing in ings:
+            name = ing.get("oil_name") or ing.get("oil", "")
+            drops = ing.get("drops", 0)
+            if name and name != "椰子油":
+                oil_drops[name] = oil_drops.get(name, 0) + drops * r["times_per_month"]
+    # Get oil metadata
+    oils_meta = {}
+    for row in conn.execute("SELECT name, bottle_price, drop_count FROM oils").fetchall():
+        oils_meta[row["name"]] = {"bottle_price": row["bottle_price"], "drop_count": row["drop_count"]}
+    # Get user inventory
+    inv = set(r["oil_name"] for r in conn.execute(
+        "SELECT oil_name FROM user_inventory WHERE user_id = ?", (plan["user_id"],)).fetchall())
+    conn.close()
+    import math
+    result = []
+    for oil, drops in sorted(oil_drops.items()):
+        meta = oils_meta.get(oil, {})
+        drop_count = meta.get("drop_count", 250)
+        bottle_price = meta.get("bottle_price", 0)
+        bottles = math.ceil(drops / drop_count) if drop_count else 1
+        result.append({
+            "oil_name": oil,
+            "monthly_drops": round(drops, 1),
+            "bottles_needed": bottles,
+            "bottle_price": bottle_price,
+            "total_cost": round(bottles * bottle_price, 2),
+            "in_inventory": oil in inv,
+        })
+    result.sort(key=lambda x: (x["in_inventory"], x["oil_name"]))
+    return result
+
+
 # ── Search Logging ─────────────────────────────────────
 @app.post("/api/search-log")
 def log_search(body: dict, user=Depends(get_current_user)):