add calculation costing per unit at date

models/stock_inventory_backdate.py

@@ -149,6 +149,53 @@ class StockInventoryBackdate(models.Model):
         
         return qty_in - qty_out
 
+    def _get_historical_cost(self, product, date, company_id):
+        """
+        Calculate historical unit cost at a specific date.
+        - Standard Price: Returns current standard price.
+        - AVCO/FIFO: Calculates historical weighted average.
+        """
+        cost_method = product.categ_id.property_cost_method
+        
+        if cost_method == 'standard':
+            return product.standard_price
+
+        # Optimized Key: Use SQL for aggregation instead of loading all objects
+        sql = """
+            SELECT SUM(quantity), SUM(value)
+            FROM stock_valuation_layer
+            WHERE product_id = %s
+              AND create_date <= %s
+              AND company_id = %s
+        """
+        self.env.cr.execute(sql, (product.id, date, company_id.id))
+        result = self.env.cr.fetchone()
+        
+        quantity = result[0] or 0.0
+        value = result[1] or 0.0
+        
+        if quantity != 0:
+            return value / quantity
+            
+        # Fallback: Try to find the last valid unit_cost from an incoming layer
+        # This helps if current stock is 0 but we want the 'last known cost'
+        last_in_sql = """
+            SELECT value, quantity
+            FROM stock_valuation_layer
+            WHERE product_id = %s
+              AND create_date <= %s
+              AND company_id = %s
+              AND quantity > 0
+            ORDER BY create_date DESC, id DESC
+            LIMIT 1
+        """
+        self.env.cr.execute(last_in_sql, (product.id, date, company_id.id))
+        last_in = self.env.cr.fetchone()
+        if last_in and last_in[1] != 0:
+            return last_in[0] / last_in[1]
+
+        return product.standard_price
+
     def action_validate(self):
         """Validate and create backdated stock moves"""
         self.ensure_one()
@@ -220,6 +267,11 @@ class StockInventoryBackdateLine(models.Model):
         default=0.0,
         help="Positive value adds stock, negative value removes stock."
     )
+    unit_cost = fields.Float(
+        string='Unit Cost',
+        digits='Product Price',
+        help="Custom unit cost for this backdated adjustment. If left 0, it may use standard price."
+    )
     product_uom_id = fields.Many2one(
         'uom.uom',
         string='Unit of Measure',
@@ -265,6 +317,17 @@ class StockInventoryBackdateLine(models.Model):
                 self.counted_qty = self.theoretical_qty
                 self.difference_qty = 0.0
             
+            # Calculate historical unit cost
+            if self.inventory_id.backdate_datetime:
+                limit_date = self.inventory_id.backdate_datetime
+                self.unit_cost = self.inventory_id._get_historical_cost(
+                    self.product_id, 
+                    limit_date, 
+                    self.inventory_id.company_id
+                )
+            else:
+                 self.unit_cost = self.product_id.standard_price
+
     def _create_stock_move(self):
         """Create backdated stock move for this line"""
         self.ensure_one()
@@ -384,19 +447,87 @@ class StockInventoryBackdateLine(models.Model):
         
         # Update stock valuation layer
         # Check if valuation layer exists
-        svl_count = self.env['stock.valuation.layer'].search_count([('stock_move_id', '=', move.id)])
+        svl = self.env['stock.valuation.layer'].search([('stock_move_id', '=', move.id)], limit=1)
-        _logger.info(f"Found {svl_count} stock valuation layers for move {move.id}")
+        # svl_count = self.env['stock.valuation.layer'].search_count([('stock_move_id', '=', move.id)])
+        _logger.info(f"Found stock valuation layer for move {move.id}: {svl}")
         
-        if svl_count > 0:
+        if svl:
-            self.env.cr.execute(
+            new_val_layer_vals = {}
-                "UPDATE stock_valuation_layer SET create_date = %s WHERE stock_move_id = %s",
+            # Update Date
-                (backdate, move.id)
+            new_val_layer_vals['create_date'] = backdate
-            )
+            
-            _logger.info(f"Updated stock_valuation_layer for move {move.id}, rows affected: {self.env.cr.rowcount}")
+            # --- COST ADJUSTMENT LOGIC ---
+            # If unit_cost is provided, we override the value on the layer
+            # and potentially update the account move
+            if self.unit_cost and self.unit_cost > 0:
+                original_value = svl.value
+                new_value = self.unit_cost * qty
+                if self.difference_qty < 0:
+                     new_value = -abs(new_value) # Ensure negative if qty is negative
+                
+                if abs(new_value - original_value) > 0.01:
+                    _logger.info(f"Overriding SVL Value from {original_value} to {new_value} (Unit Cost: {self.unit_cost})")
+                    
+                    # Update SVL via SQL to avoid constraint issues or re-triggering logic
+                    # Also need to update remaining_value if applicable?
+                    # For incoming (positive diff), remaining_value should match value.
+                    # For outgoing, usually remaining_value is 0 on the layer itself (it consumes others).
+                    
+                    update_sql = "UPDATE stock_valuation_layer SET create_date = %s, value = %s, unit_cost = %s"
+                    params = [backdate, new_value, self.unit_cost]
+                    
+                    if self.difference_qty > 0:
+                        # Incoming: update remaining_value too
+                        update_sql += ", remaining_value = %s"
+                        params.append(new_value)
+                        
+                    update_sql += " WHERE id = %s"
+                    params.append(svl.id)
+                    
+                    self.env.cr.execute(update_sql, tuple(params))
+                    
+                    # Check Account Move and update amount
+                    if move.account_move_ids:
+                        for am in move.account_move_ids:
+                            # Update lines
+                            # We need to find which line is Debit/Credit and scale them?
+                            # Or just assuming 2 lines, simpler to match the total?
+                            # Let's check amounts.
+                            
+                            # Usually Inventory Adjustment creates:
+                            # Dr Stock, Cr Inventory Adjustment (for Gain)
+                            # Dr Inventory Adjustment, Cr Stock (for Loss)
+                            
+                            # We just need to replace the absolute amount on all lines that matched the old absolute amount?
+                            # Risky if multiple lines.
+                            
+                            # Better: Iterate lines. If line amount matches old abs(value), update to new abs(value).
+                            for line in am.line_ids:
+                                if abs(line.debit - abs(original_value)) < 0.01:
+                                    self.env.cr.execute("UPDATE account_move_line SET debit = %s WHERE id = %s", (abs(new_value), line.id))
+                                if abs(line.credit - abs(original_value)) < 0.01:
+                                    self.env.cr.execute("UPDATE account_move_line SET credit = %s WHERE id = %s", (abs(new_value), line.id))
+                            
+                            _logger.info(f"Updated account_move {am.id} amounts to match new value {new_value}")
+
+                else:
+                    # just update date
+                   self.env.cr.execute(
+                        "UPDATE stock_valuation_layer SET create_date = %s WHERE id = %s",
+                        (backdate, svl.id)
+                    )
+            else:
+                 # No custom cost, just update date
+                 self.env.cr.execute(
+                    "UPDATE stock_valuation_layer SET create_date = %s WHERE id = %s",
+                    (backdate, svl.id)
+                )
+
+            _logger.info(f"Updated stock_valuation_layer for move {move.id}")
         else:
             _logger.warning(f"No stock valuation layer found for move {move.id}. Product may not use real-time valuation or cost is zero.")
         
-        # Update account moves if they exist
+        # Update account moves dates if they exist (Run unconditionally as date fix is always needed)
         # Refresh move to get account_move_ids
         move = self.env['stock.move'].browse(move.id)
         if move.account_move_ids:

views/stock_inventory_backdate_views.xml

@@ -65,6 +65,7 @@
                                            decoration-warning="theoretical_qty < 0"
                                            force_save="1"/>
                                     <field name="counted_qty"/>
+                                    <field name="unit_cost" optional="show" required="1"/>
                                     <field name="difference_qty" sum="Total Adjustment"/>
                                     <field name="product_uom_id" string="UoM" groups="uom.group_uom"/>
                                     <field name="has_negative_theoretical" column_invisible="1"/>