From 100a4390e7bab397689a94bc44e349c4bf2f4f8f Mon Sep 17 00:00:00 2001
From: vickytechkey <vichunice@gmail.com>
Date: Sun, 25 Oct 2026 14:49:56 +0530
Subject: [PATCH] feat: add document verification API serializers and views

---
 verifier/serializers.py | 12 ++++++++++++
 verifier/views.py       | 33 ++++++++++++++++++++++-----------
 2 files changed, 34 insertions(+), 11 deletions(-)

diff --git a/verifier/serializers.py b/verifier/serializers.py
index 1be2c0b..c45eb8a 100644
--- a/verifier/serializers.py
+++ b/verifier/serializers.py
@@ -12,6 +12,12 @@ class VerifyDocumentRequestSerializer(serializers.Serializer):
         required=True,
         help_text="Document verification attributes (e.g. pan_number, name, dob, etc.)",
     )
+    business_name = serializers.CharField(
+        required=False,
+        allow_blank=True,
+        allow_null=True,
+        help_text="Optional legal entity or trade name of the business to match against GSTIN.",
+    )
     preferred_vendor = serializers.CharField(
         required=False,
         allow_null=True,
@@ -39,6 +45,12 @@ class VerifySellerPanGstRequestSerializer(serializers.Serializer):
         max_length=15,
         help_text="Optional GSTIN entered by seller to cross-verify against linked GST records.",
     )
+    business_name = serializers.CharField(
+        required=False,
+        allow_blank=True,
+        allow_null=True,
+        help_text="Optional legal entity or trade name of the business to match against GSTIN.",
+    )
     preferred_vendor = serializers.CharField(
         required=False,
         allow_blank=True,
diff --git a/verifier/views.py b/verifier/views.py
index eb6e356..37427d5 100644
--- a/verifier/views.py
+++ b/verifier/views.py
@@ -372,6 +372,7 @@ class SellerPanGstVerifyView(APIView):
         seller_name = serializer.validated_data["seller_name"].strip()
         pan = serializer.validated_data["pan"].strip().upper()
         entered_gstin = (serializer.validated_data.get("gstin") or "").strip().upper()
+        business_name = (serializer.validated_data.get("business_name") or request.data.get("business_name") or "").strip()
         preferred_vendor = serializer.validated_data.get("preferred_vendor")
 
         start_time = time.time()
@@ -492,10 +493,8 @@ class SellerPanGstVerifyView(APIView):
                         gstin_matched = True
                         break
 
-            # Validate that 15-character GSTIN contains the 10-character PAN at chars 3-12
-            if len(target_gstin) == 15 and target_gstin[2:12].upper() != pan.upper():
-                gstin_matched = False
-                gst_error = f"GSTIN '{target_gstin}' does not match the provided PAN card '{pan}'."
+            # Do not restrict GSTIN to individual PAN. Entities/companies have their own PAN inside their GSTIN.
+            # Just verify that the GSTIN exists and is active.
 
             # Check if matching record has legal_name
             if matching_gst_record and matching_gst_record.get("legal_name"):
@@ -529,13 +528,25 @@ class SellerPanGstVerifyView(APIView):
             if not verified_gst_name and gstin_matched:
                 verified_gst_name = verified_pan_name
 
-            # Compare GST legal name against seller full name and verified PAN name
-            if verified_gst_name:
-                gst_name_match = compare_names(seller_name, verified_gst_name)
-                if not gst_name_match["matched"] and verified_pan_name:
-                    pan_to_gst_match = compare_names(verified_pan_name, verified_gst_name)
-                    if pan_to_gst_match["matched"]:
-                        gst_name_match = pan_to_gst_match
+            # Compare GST legal name and trade name against business name (as per GST), seller name, and verified PAN name
+            gst_candidates = [n for n in [verified_gst_name, gst_details.get("legalName"), gst_details.get("tradeName")] if n]
+            
+            # 1. Primary: Match against entered business name (as per GST)
+            if business_name:
+                for candidate in gst_candidates:
+                    b_match = compare_names(business_name, candidate)
+                    if b_match["matched"]:
+                        gst_name_match = b_match
+                        break
+
+            # 2. Fallback: Match against seller name or verified PAN name
+            if not gst_name_match.get("matched", False):
+                if verified_gst_name:
+                    gst_name_match = compare_names(seller_name, verified_gst_name)
+                    if not gst_name_match["matched"] and verified_pan_name:
+                        pan_to_gst_match = compare_names(verified_pan_name, verified_gst_name)
+                        if pan_to_gst_match["matched"]:
+                            gst_name_match = pan_to_gst_match
 
         total_latency = (time.time() - start_time) * 1000