feat: Phase 2A — product cost tracking

- Products: add cost_simple (flat €) and cost_breakdown (JSON line items)
- OrderItems: add unit_cost snapshot written at time of order creation
- Snapshot logic: breakdown sum takes priority over cost_simple; NULL if neither set
- Product schema: serialize/deserialize cost_breakdown as JSON; expose in API
- Product performance report: add trackable_profit, uncosted_revenue, has_gap per product
- Manager UI: cost section in product edit form (simple / detailed toggle with live margin %)
- Products list: show margin % or cost-error badge per product
- Product performance report: profit column + gap warning banner

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

local_backend/main.py

@@ -262,6 +262,10 @@ def _run_migrations():
             created_at DATETIME DEFAULT CURRENT_TIMESTAMP,
             updated_at DATETIME DEFAULT CURRENT_TIMESTAMP
         )""",
+        # Phase 2A — product cost tracking
+        "ALTER TABLE products ADD COLUMN cost_simple REAL",
+        "ALTER TABLE products ADD COLUMN cost_breakdown TEXT",
+        "ALTER TABLE order_items ADD COLUMN unit_cost REAL",
     ]
     for sql in migrations:
         try:

local_backend/models/order.py

@@ -75,6 +75,9 @@ class OrderItem(Base):
     payment_method = Column(String, nullable=True)  # 'cash'|'card'|'other' — future use
     paid_in_shift_id = Column(Integer, ForeignKey("waiter_shifts.id"), nullable=True)
 
+    # Phase 2A — cost snapshot (copied from product at time of order, never updated)
+    unit_cost = Column(Float, nullable=True)
+
     order = relationship("Order", back_populates="items")
     product = relationship("Product", back_populates="order_items")
     added_by_user = relationship("User", foreign_keys=[added_by], back_populates="order_items")

local_backend/models/product.py

@@ -46,6 +46,10 @@ class Product(Base):
     digital_discount = Column(Float, default=0.0, nullable=False)
     digital_image_url = Column(String, nullable=True)
 
+    # Phase 2A — cost tracking
+    cost_simple = Column(Float, nullable=True)
+    cost_breakdown = Column(Text, nullable=True)  # JSON: [{"label": str, "amount": float}]
+
     category = relationship("Category", back_populates="products")
     printer_zone = relationship("Printer", back_populates="products")
     quick_options = relationship("ProductQuickOption", back_populates="product", cascade="all, delete-orphan")

local_backend/routers/orders.py

@@ -270,12 +270,25 @@ def add_items(
             (o.price_delta or o.extra_cost or 0.0)
             for o in (item_in.selected_options or [])
         )
+        # Phase 2A: cost snapshot — breakdown takes priority over simple cost
+        unit_cost = None
+        if product.cost_breakdown:
+            try:
+                entries = json.loads(product.cost_breakdown)
+                total = sum(e.get("amount", 0.0) for e in entries if isinstance(e, dict))
+                if total > 0:
+                    unit_cost = total
+            except Exception:
+                pass
+        if unit_cost is None and product.cost_simple:
+            unit_cost = product.cost_simple
         item = OrderItem(
             order_id=order_id,
             product_id=item_in.product_id,
             added_by=user.id,
             quantity=item_in.quantity,
             unit_price=product.base_price + extra_cost,
+            unit_cost=unit_cost,
             selected_options=json.dumps([o.model_dump() for o in item_in.selected_options]) if item_in.selected_options else None,
             removed_ingredients=json.dumps(item_in.removed_ingredients) if item_in.removed_ingredients else None,
             notes=item_in.notes,

local_backend/routers/products.py

@@ -235,9 +235,11 @@ def reorder_products(items: List[ProductReorderItem], db: Session = Depends(get_
 
 @router.post("/", response_model=ProductOut, status_code=status.HTTP_201_CREATED)
 def create_product(body: ProductCreate, db: Session = Depends(get_db), user: User = Depends(require_manager)):
-    data = body.model_dump(exclude={"quick_options", "options", "ingredients", "preference_sets"})
+    data = body.model_dump(exclude={"quick_options", "options", "ingredients", "preference_sets", "cost_breakdown"})
     if data.get("sort_order") == 0:
         data["sort_order"] = db.query(Product).count()
+    if body.cost_breakdown is not None:
+        data["cost_breakdown"] = json.dumps([item.model_dump() for item in body.cost_breakdown])
     product = Product(**data)
     db.add(product)
     db.flush()
@@ -277,8 +279,18 @@ def update_product(product_id: int, body: ProductUpdate, db: Session = Depends(g
     product = db.query(Product).filter(Product.id == product_id).first()
     if not product:
         raise HTTPException(status_code=404, detail="Product not found")
-    for field, value in body.model_dump(exclude_none=True, exclude={"quick_options", "options", "ingredients", "preference_sets"}).items():
+    scalar_fields = body.model_dump(
+        exclude_none=True,
+        exclude={"quick_options", "options", "ingredients", "preference_sets", "cost_breakdown"},
+    )
+    for field, value in scalar_fields.items():
         setattr(product, field, value)
+    # cost_breakdown is a list of objects — serialize to JSON for storage
+    if body.cost_breakdown is not None:
+        product.cost_breakdown = json.dumps([item.model_dump() for item in body.cost_breakdown])
+    elif "cost_breakdown" in body.model_fields_set:
+        # explicitly set to null — clear it
+        product.cost_breakdown = None
     if body.quick_options is not None:
         _replace_quick_options(db, product, body.quick_options)
     if body.options is not None:

local_backend/routers/reports.py

@@ -950,16 +950,29 @@ def product_performance(
                 "category_id": product.category_id if product else None,
                 "qty_sold": 0,
                 "revenue": 0.0,
+                "trackable_profit": 0.0,
+                "uncosted_revenue": 0.0,
+                "uncosted_items": 0,
                 "order_ids": set(),
             }
-        summary[pid]["qty_sold"] += item.quantity
+        qty = item.quantity
-        summary[pid]["revenue"] += item.unit_price * item.quantity
+        revenue = item.unit_price * qty
+        summary[pid]["qty_sold"] += qty
+        summary[pid]["revenue"] += revenue
         summary[pid]["order_ids"].add(item.order_id)
+        if item.unit_cost is not None:
+            summary[pid]["trackable_profit"] += revenue - (item.unit_cost * qty)
+        else:
+            summary[pid]["uncosted_revenue"] += revenue
+            summary[pid]["uncosted_items"] += qty
 
     result = []
     for entry in summary.values():
         entry["order_count"] = len(entry.pop("order_ids"))
         entry["revenue"] = round(entry["revenue"], 2)
+        entry["trackable_profit"] = round(entry["trackable_profit"], 2)
+        entry["uncosted_revenue"] = round(entry["uncosted_revenue"], 2)
+        entry["has_gap"] = entry["uncosted_items"] > 0
         result.append(entry)
 
     result.sort(key=lambda x: x["qty_sold"], reverse=True)

local_backend/schemas/product.py

@@ -255,6 +255,11 @@ class PreferenceSetOut(BaseModel):
 
 # ── Products ──────────────────────────────────────────────────────────────────
 
+class CostBreakdownItem(BaseModel):
+    label: str
+    amount: float
+
+
 class ProductBase(BaseModel):
     name: str
     description: Optional[str] = None
@@ -272,6 +277,9 @@ class ProductBase(BaseModel):
     digital_price: Optional[float] = None
     digital_discount: Optional[float] = None
     digital_image_url: Optional[str] = None
+    # Phase 2A — cost tracking
+    cost_simple: Optional[float] = None
+    cost_breakdown: Optional[List[CostBreakdownItem]] = None
 
 
 class ProductCreate(ProductBase):
@@ -302,6 +310,9 @@ class ProductUpdate(BaseModel):
     digital_price: Optional[float] = None
     digital_discount: Optional[float] = None
     digital_image_url: Optional[str] = None
+    # Phase 2A — cost tracking
+    cost_simple: Optional[float] = None
+    cost_breakdown: Optional[List[CostBreakdownItem]] = None
 
 
 class ProductReorderItem(BaseModel):
@@ -318,3 +329,42 @@ class ProductOut(ProductBase):
     image_url: Optional[str] = None
 
     model_config = {"from_attributes": True}
+
+    @model_validator(mode='before')
+    @classmethod
+    def parse_cost_breakdown(cls, data: Any) -> Any:
+        if hasattr(data, 'cost_breakdown'):
+            raw = data.cost_breakdown
+            parsed = None
+            if isinstance(raw, str):
+                try:
+                    parsed = json.loads(raw)
+                except Exception:
+                    parsed = None
+            # Return a plain dict so other validators still see all fields
+            return {
+                'id': data.id,
+                'name': data.name,
+                'description': data.description,
+                'category_id': data.category_id,
+                'base_price': data.base_price,
+                'is_available': data.is_available,
+                'lifecycle_status': data.lifecycle_status,
+                'printer_zone_id': data.printer_zone_id,
+                'sort_order': data.sort_order,
+                'image_url': data.image_url,
+                'digital_visible': bool(data.digital_visible),
+                'digital_available': bool(data.digital_available),
+                'digital_name': data.digital_name,
+                'digital_description': data.digital_description,
+                'digital_price': data.digital_price,
+                'digital_discount': data.digital_discount,
+                'digital_image_url': data.digital_image_url,
+                'cost_simple': data.cost_simple,
+                'cost_breakdown': parsed,
+                'quick_options': list(data.quick_options),
+                'options': list(data.options),
+                'ingredients': list(data.ingredients),
+                'preference_sets': list(data.preference_sets),
+            }
+        return data

manager_dashboard/src/pages/Management/ProductFormModal.jsx

@@ -146,6 +146,12 @@ function buildFormFromProduct(product) {
     digital_image_url: product.digital_image_url ?? '',
     digital_price: product.digital_price ?? '',
     digital_discount: product.digital_discount ?? '',
+    // Phase 2A — cost tracking
+    cost_mode: product.cost_breakdown?.length ? 'detailed' : 'simple',
+    cost_simple: product.cost_simple ?? '',
+    cost_breakdown: product.cost_breakdown?.length
+      ? product.cost_breakdown.map(e => ({ label: e.label, amount: e.amount }))
+      : [],
   }
 }
 
@@ -439,6 +445,11 @@ export default function ProductFormModal({ product, categories, printers, onSave
       digital_image_url: form.digital_image_url || null,
       digital_price: form.digital_price !== '' ? parseFloat(form.digital_price) : null,
       digital_discount: form.digital_discount !== '' ? parseFloat(form.digital_discount) : null,
+      // Phase 2A — cost tracking
+      cost_simple: form.cost_mode === 'simple' && form.cost_simple !== '' ? parseFloat(form.cost_simple) : null,
+      cost_breakdown: form.cost_mode === 'detailed' && form.cost_breakdown.length > 0
+        ? form.cost_breakdown.map(e => ({ label: e.label, amount: parseFloat(e.amount) || 0 }))
+        : null,
     }
   }
 
@@ -524,6 +535,75 @@ export default function ProductFormModal({ product, categories, printers, onSave
               <PriceInput value={form.base_price} onChange={v => setField('base_price', v)} className="w-full" />
             </div>
 
+            {/* Phase 2A — Cost section */}
+            <div className="rounded-xl border border-gray-200 bg-white overflow-hidden">
+              <div className="flex items-center justify-between px-3 py-2.5 bg-gray-50 border-b border-gray-200">
+                <span className="text-xs font-semibold text-gray-500 uppercase tracking-widest">Κόστος</span>
+                <div className="flex gap-1">
+                  {['simple', 'detailed'].map(mode => (
+                    <button key={mode} type="button"
+                      onClick={() => setField('cost_mode', mode)}
+                      className={`px-2 py-0.5 rounded text-xs font-medium transition-colors ${
+                        form.cost_mode === mode
+                          ? 'bg-primary-600 text-white'
+                          : 'text-gray-500 hover:bg-gray-100'
+                      }`}>
+                      {mode === 'simple' ? 'Απλό' : 'Ανάλυση'}
+                    </button>
+                  ))}
+                </div>
+              </div>
+              <div className="p-3 space-y-2">
+                {form.cost_mode === 'simple' ? (
+                  <div>
+                    <label className="label text-xs">Κόστος ανά μονάδα (€)</label>
+                    <PriceInput value={form.cost_simple} onChange={v => setField('cost_simple', v)} className="w-full" />
+                    {form.cost_simple !== '' && parseFloat(form.base_price) > 0 && parseFloat(form.cost_simple) > 0 && (() => {
+                      const margin = ((parseFloat(form.base_price) - parseFloat(form.cost_simple)) / parseFloat(form.base_price) * 100)
+                      const isError = parseFloat(form.cost_simple) > parseFloat(form.base_price)
+                      return (
+                        <p className={`text-xs mt-1 font-medium ${isError ? 'text-red-500' : 'text-green-600'}`}>
+                          {isError ? '⚠ Κόστος > Τιμή' : `Περιθώριο: ${margin.toFixed(1)}%`}
+                        </p>
+                      )
+                    })()}
+                  </div>
+                ) : (
+                  <div className="space-y-2">
+                    {form.cost_breakdown.map((entry, bi) => (
+                      <div key={bi} className="flex gap-2 items-center">
+                        <input className="input flex-1 text-sm" placeholder="π.χ. Γάλα"
+                          value={entry.label}
+                          onChange={e => setForm(f => ({ ...f, cost_breakdown: f.cost_breakdown.map((x, i) => i === bi ? { ...x, label: e.target.value } : x) }))} />
+                        <PriceInput value={entry.amount}
+                          onChange={v => setForm(f => ({ ...f, cost_breakdown: f.cost_breakdown.map((x, i) => i === bi ? { ...x, amount: v } : x) }))}
+                          className="w-28" />
+                        <button type="button"
+                          onClick={() => setForm(f => ({ ...f, cost_breakdown: f.cost_breakdown.filter((_, i) => i !== bi) }))}
+                          className="text-gray-400 hover:text-red-500 px-1.5 text-sm shrink-0">✕</button>
+                      </div>
+                    ))}
+                    <button type="button"
+                      onClick={() => setForm(f => ({ ...f, cost_breakdown: [...f.cost_breakdown, { label: '', amount: 0 }] }))}
+                      className="text-xs text-primary-600 hover:text-primary-800 font-medium">+ Γραμμή κόστους</button>
+                    {form.cost_breakdown.length > 0 && (() => {
+                      const total = form.cost_breakdown.reduce((s, e) => s + (parseFloat(e.amount) || 0), 0)
+                      const price = parseFloat(form.base_price) || 0
+                      const isError = total > price && price > 0
+                      const margin = price > 0 ? ((price - total) / price * 100) : null
+                      return (
+                        <div className={`text-xs font-medium ${isError ? 'text-red-500' : 'text-gray-600'}`}>
+                          Σύνολο: €{total.toFixed(2)}
+                          {margin !== null && !isError && <span className="text-green-600 ml-2">({margin.toFixed(1)}% περιθώριο)</span>}
+                          {isError && <span className="ml-1">— Κόστος > Τιμή!</span>}
+                        </div>
+                      )
+                    })()}
+                  </div>
+                )}
+              </div>
+            </div>
+
             <div>
               <label className="label">Κατηγορία</label>
               <select className="input" value={form.category_id} onChange={e => setField('category_id', e.target.value)}>

manager_dashboard/src/pages/Management/ProductsTab.jsx

@@ -845,10 +845,29 @@ function ProductRow({ p, cat, parentCat, selected, onToggleSelect, onEdit, onArc
           </div>
         </div>
 
-        {/* Price */}
+        {/* Price + cost/margin */}
-        <span style={{ fontVariantNumeric: 'tabular-nums', fontWeight: 600, fontSize: 14, color: '#111827', marginRight: 4, whiteSpace: 'nowrap' }}>
+        <div style={{ display: 'flex', flexDirection: 'column', alignItems: 'flex-end', gap: 2, marginRight: 4, flexShrink: 0 }}>
+          <span style={{ fontVariantNumeric: 'tabular-nums', fontWeight: 600, fontSize: 14, color: '#111827', whiteSpace: 'nowrap' }}>
             €{parseFloat(p.base_price).toFixed(2)}
           </span>
+          {(() => {
+            const effectiveCost = p.cost_breakdown?.length
+              ? p.cost_breakdown.reduce((s, e) => s + (e.amount || 0), 0)
+              : (p.cost_simple ?? null)
+            if (effectiveCost === null) return null
+            const price = parseFloat(p.base_price)
+            const isError = effectiveCost > price
+            const margin = price > 0 ? ((price - effectiveCost) / price * 100) : null
+            return (
+              <span style={{
+                fontSize: 11, fontWeight: 500, whiteSpace: 'nowrap',
+                color: isError ? '#ef4444' : '#16a34a',
+              }}>
+                {isError ? '⚠ κόστος > τιμή' : margin !== null ? `${margin.toFixed(0)}% margin` : null}
+              </span>
+            )
+          })()}
+        </div>
 
         {/* Actions */}
         <div style={{ display: 'flex', alignItems: 'center', gap: 5, flexShrink: 0 }}>

manager_dashboard/src/pages/reports/restaurant/ProductPerformance.jsx

@@ -350,29 +350,87 @@ export default function ProductPerformance() {
         </Panel>
 
         <div className="mt-4">
-          <Panel title="Όλα τα Προϊόντα" subtitle={`${products.length} προϊόντα με πωλήσεις`} padded={false}>
+          {(() => {
+            const totalProfit = products.reduce((s, p) => s + (p.trackable_profit || 0), 0)
+            const totalUncostedRev = products.reduce((s, p) => s + (p.uncosted_revenue || 0), 0)
+            const hasGap = products.some(p => p.has_gap)
+            return (
+              <Panel
+                title="Όλα τα Προϊόντα"
+                subtitle={`${products.length} προϊόντα με πωλήσεις`}
+                padded={false}
+              >
+                {hasGap && (
+                  <div className="mx-4 mt-3 mb-1 flex items-start gap-2 rounded-lg border border-amber-200 bg-amber-50 px-3 py-2.5 text-[12px] text-amber-800">
+                    <span className="shrink-0 font-bold">⚠</span>
+                    <span>
+                      Μερικά προϊόντα δεν έχουν κόστος — το κέρδος που φαίνεται είναι μερικό.
+                      Ορισμένα έσοδα <strong>{fmtEUR(totalUncostedRev)}</strong> δεν συμπεριλαμβάνονται στο κέρδος.{' '}
+                      <a href="/management?tab=products" className="underline hover:text-amber-900">Ορισμός κόστους προϊόντων →</a>
+                    </span>
+                  </div>
+                )}
                 {products.length === 0 ? (
                   <EmptyState title="Δεν βρέθηκαν προϊόντα" description="Δεν υπάρχουν πωλήσεις σε αυτή την περίοδο." />
                 ) : (
                   <DataTable>
-                <THead><TH>Προϊόν</TH><TH align="right">Τεμάχια</TH><TH align="right">Έσοδα</TH><TH align="right">% Συνόλου</TH><TH align="right">Παραγγελίες</TH></THead>
+                    <THead>
+                      <TH>Προϊόν</TH>
+                      <TH align="right">Τεμάχια</TH>
+                      <TH align="right">Έσοδα</TH>
+                      <TH align="right">Κέρδος</TH>
+                      <TH align="right">% Συνόλου</TH>
+                      <TH align="right">Παραγγελίες</TH>
+                    </THead>
                     <tbody>
                       {products.map(p => {
                         const pct = totalRev ? (p.revenue / totalRev * 100) : 0
+                        const margin = p.revenue > 0 && !p.has_gap
+                          ? ((p.trackable_profit / p.revenue) * 100).toFixed(0) + '%'
+                          : null
                         return (
                           <TR key={p.product_id} striped>
                             <TD className="font-medium text-slate-900">{p.product_name}</TD>
                             <TD mono align="right">{fmtNum(p.qty_sold)}</TD>
                             <TD mono align="right" className="font-semibold text-slate-900">{fmtEUR(p.revenue)}</TD>
+                            <TD mono align="right">
+                              {p.has_gap ? (
+                                <span className="text-amber-500 text-[11px]">⚠ χωρίς κόστος</span>
+                              ) : (
+                                <span className={p.trackable_profit >= 0 ? 'text-green-700' : 'text-red-600'}>
+                                  {fmtEUR(p.trackable_profit)}
+                                  {margin && <span className="ml-1 text-[10px] text-slate-400">({margin})</span>}
+                                </span>
+                              )}
+                            </TD>
                             <TD mono align="right">{pct.toFixed(1)}%</TD>
                             <TD mono align="right">{fmtNum(p.order_count)}</TD>
                           </TR>
                         )
                       })}
                     </tbody>
+                    {products.length > 1 && (
+                      <tfoot>
+                        <TR>
+                          <TD className="font-semibold text-slate-700" colSpan={2}>Σύνολο</TD>
+                          <TD mono align="right" className="font-bold">{fmtEUR(totalRev)}</TD>
+                          <TD mono align="right" className="font-bold">
+                            {hasGap ? (
+                              <span className="text-amber-600">{fmtEUR(totalProfit)} {' '}<span className="text-[10px]">+χωρίς κόστος</span></span>
+                            ) : (
+                              <span className="text-green-700">{fmtEUR(totalProfit)}</span>
+                            )}
+                          </TD>
+                          <TD mono align="right" className="font-bold">100%</TD>
+                          <TD />
+                        </TR>
+                      </tfoot>
+                    )}
                   </DataTable>
                 )}
               </Panel>
+            )
+          })()}
         </div>
       </div>