feat(vat): Certificate VAT Report (Cədvəl 23) + auto-fill Əlavə 8

- New Script Report "Certificate VAT Report": one row per sales-invoice item
  certificate (cert no, VÖEN, taxpayer, value), full item amount per certificate
  with no splitting; filters company + date range, submitted invoices only.
- Auto-fill VAT declaration Əlavə 8 Table 2 (müəssisə_malın_dəyəri) from that
  report inside populate_vat_tables; split cert_no into series (letters, max 3)
  and number (digits).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

taxes_az/taxes_az/doctype/declaration_of_value_added_tax/declaration_of_value_added_tax.js

@@ -31,6 +31,7 @@ function fill_from_reports(frm) {
 			set_table(frm, "əlavə_1", r.message.elave_1);
 			set_table(frm, "əlavə_2", r.message.elave_2);
 			set_table(frm, "əlavə_2_2", r.message.elave_2_2);
+			set_table(frm, "müəssisə_malın_dəyəri", r.message.elave_8_2);
 
 			frm.refresh_fields();
 			frappe.show_alert({ message: __("Əlavələr hesabatlardan dolduruldu"), indicator: "green" });

taxes_az/taxes_az/doctype/declaration_of_value_added_tax/declaration_of_value_added_tax.py

@@ -7,6 +7,7 @@ from frappe import _
 from frappe.utils import flt, getdate, add_months, cint
 from datetime import datetime, date
 import calendar
+import re
 
 class Declarationofvalueaddedtax(Document):
 	pass
@@ -26,6 +27,21 @@ ACT_TYPE_MAP = {
 }
 
 
+def _split_cert_no(cert_no):
+    """Split a combined certificate number into (series, number).
+
+    Leading letters are the series, the trailing digits are the number, e.g.
+    "Az10000001" -> ("Az", "10000001"). If there are no leading letters the
+    whole value becomes the number. The series field is 3 chars wide, so it is
+    capped to 3 to avoid truncation errors.
+    """
+    s = (cert_no or "").strip()
+    m = re.match(r"^([^\d]+)(\d.*)$", s)
+    if m:
+        return m.group(1).strip()[:3], m.group(2).strip()
+    return "", s
+
+
 def _period_filters(year, month):
 	"""Build report filters (company + month date range) from year + month."""
 	from frappe.utils import get_last_day
@@ -58,6 +74,9 @@ def populate_vat_tables(year, month):
 	from taxes_az.taxes_az.report.agricultural_goods_stock_report.agricultural_goods_stock_report import (
 		get_data as agri_get_data,
 	)
+	from taxes_az.taxes_az.report.certificate_vat_report.certificate_vat_report import (
+		get_data as certificate_get_data,
+	)
 
 	if not month or not year:
 		return {"success": False, "error": "Year and month are required"}
@@ -98,10 +117,25 @@ def populate_vat_tables(year, month):
 			"hesabatdövründəsatılmışmallaragörəticarətəlavəsininədvməbləği": r.get("trade_markup_vat"),
 		})
 
+	# Əlavə 8 Tablo 2 (müəssisə_malın_dəyəri) — one row per certificate presented
+	# on a sales invoice, with the value of goods supplied under it. The full
+	# item amount is kept per certificate (no splitting across certificates).
+	elave_8_2 = []
+	for r in (certificate_get_data(filters) or []):
+		series, number = _split_cert_no(r.get("cert_no"))
+		elave_8_2.append({
+			"şəxsinadı": r.get("taxpayer_full_name"),
+			"şəxsinvöeni": r.get("voen") or None,
+			"sertifikatınseriyası": series,
+			"nsi": number,
+			"xidmətindəyəri": r.get("value"),
+		})
+
 	return {
 		"success": True,
 		"elave_1": elave_1,
 		"elave_2": elave_2,
 		"elave_2_2": elave_2_2,
+		"elave_8_2": elave_8_2,
 		"period": filters,
 	}

taxes_az/taxes_az/report/certificate_vat_report/certificate_vat_report.js

@@ -0,0 +1,29 @@
+// Copyright (c) 2026, Your Company and contributors
+// For license information, please see license.txt
+
+frappe.query_reports["Certificate VAT Report"] = {
+	filters: [
+		{
+			fieldname: "company",
+			label: __("Company"),
+			fieldtype: "Link",
+			options: "Company",
+			default: frappe.defaults.get_user_default("Company"),
+			reqd: 1,
+		},
+		{
+			fieldname: "from_date",
+			label: __("From Date"),
+			fieldtype: "Date",
+			default: frappe.datetime.month_start(),
+			reqd: 1,
+		},
+		{
+			fieldname: "to_date",
+			label: __("To Date"),
+			fieldtype: "Date",
+			default: frappe.datetime.month_end(),
+			reqd: 1,
+		},
+	],
+};

taxes_az/taxes_az/report/certificate_vat_report/certificate_vat_report.json

@@ -0,0 +1,33 @@
+{
+ "add_total_row": 1,
+ "columns": [],
+ "creation": "2026-06-29 13:00:00.000000",
+ "disabled": 0,
+ "docstatus": 0,
+ "doctype": "Report",
+ "filters": [],
+ "idx": 0,
+ "is_standard": "Yes",
+ "letterhead": null,
+ "modified": "2026-06-29 13:00:00.000000",
+ "modified_by": "Administrator",
+ "module": "Taxes Az",
+ "name": "Certificate VAT Report",
+ "owner": "Administrator",
+ "prepared_report": 0,
+ "ref_doctype": "Sales Invoice",
+ "report_name": "Certificate VAT Report",
+ "report_type": "Script Report",
+ "roles": [
+  {
+   "role": "Accounts User"
+  },
+  {
+   "role": "Accounts Manager"
+  },
+  {
+   "role": "System Manager"
+  }
+ ],
+ "timeout": 0
+}

taxes_az/taxes_az/report/certificate_vat_report/certificate_vat_report.py

@@ -0,0 +1,97 @@
+# Copyright (c) 2026, Your Company and contributors
+# For license information, please see license.txt
+
+import frappe
+from frappe import _
+
+# Cədvəl 23 — "ƏDV - Sertifikat".
+#
+# One row per (item certificate). Certificates are stored on the Sales Invoice
+# parent in the `custom_item_certificates` table (doctype "Sales Invoice
+# Certificate"), each row linked to its item row by `parent_row` ==
+# `Sales Invoice Item.custom_si_row_key`. If one item carries 3 certificates we
+# emit 3 rows, each with the item's FULL amount — the value is intentionally not
+# split across certificates.
+
+
+def execute(filters=None):
+    filters = filters or {}
+    return get_columns(), get_data(filters)
+
+
+def get_columns():
+    return [
+        {
+            "fieldname": "sales_invoice",
+            "label": _("Sales Invoice"),
+            "fieldtype": "Link",
+            "options": "Sales Invoice",
+            "width": 160,
+        },
+        {
+            "fieldname": "posting_date",
+            "label": _("Date"),
+            "fieldtype": "Date",
+            "width": 100,
+        },
+        {
+            "fieldname": "cert_no",
+            "label": _("Sertifikatın seriya / nömrəsi"),
+            "fieldtype": "Data",
+            "width": 200,
+        },
+        {
+            "fieldname": "voen",
+            "label": _("Sertifikat təqdim olunan şəxsin Vöeni"),
+            "fieldtype": "Data",
+            "width": 170,
+        },
+        {
+            "fieldname": "taxpayer_full_name",
+            "label": _("Sertifikat təqdim olunan şəxsin adı"),
+            "fieldtype": "Data",
+            "width": 280,
+        },
+        {
+            "fieldname": "value",
+            "label": _("Sertifikat altında təqdim olunan malların (işlərin, xidmətlərin) dəyəri"),
+            "fieldtype": "Currency",
+            "width": 230,
+        },
+    ]
+
+
+def get_data(filters):
+    conditions = ""
+    if filters.get("company"):
+        conditions += " AND si.company = %(company)s"
+    if filters.get("from_date"):
+        conditions += " AND si.posting_date >= %(from_date)s"
+    if filters.get("to_date"):
+        conditions += " AND si.posting_date <= %(to_date)s"
+
+    return frappe.db.sql(
+        """
+        SELECT
+            sic.parent              AS sales_invoice,
+            si.posting_date         AS posting_date,
+            epc.cert_no             AS cert_no,
+            epc.voen                AS voen,
+            epc.taxpayer_full_name  AS taxpayer_full_name,
+            sii.amount              AS value
+        FROM `tabSales Invoice Certificate` sic
+        INNER JOIN `tabSales Invoice` si
+            ON si.name = sic.parent AND si.docstatus = 1
+        INNER JOIN `tabSales Invoice Item` sii
+            ON sii.parent = sic.parent
+           AND sii.custom_si_row_key = sic.parent_row
+        LEFT JOIN `tabE-Taxes Presented Certificate` epc
+            ON epc.name = sic.certificate
+        WHERE sic.parenttype = 'Sales Invoice'
+          AND sic.certificate IS NOT NULL AND sic.certificate != ''
+          {conditions}
+        ORDER BY si.posting_date DESC, sic.parent, epc.cert_no
+        """.format(conditions=conditions),
+        filters,
+        as_dict=True,
+    )