From aea310a3dd795457be66641ed820cab0ae966464 Mon Sep 17 00:00:00 2001
From: Kylesoda <249518290+kylesoda@users.noreply.github.com>
Date: Tue, 7 Apr 2026 10:05:45 -0500
Subject: [PATCH] feat: add WKB to EWKB conversion with SRID handling and
 integrate into MSSQL transformation

---
 cmd/go_migrate/mssql-transform.go | 38 ++++++++++++++++++++
 cmd/go_migrate/process.go         |  6 +++-
 scripts/wkb-to-ewkb/main.go       | 59 +++++++++++++++++++++++++++++++
 3 files changed, 102 insertions(+), 1 deletion(-)
 create mode 100644 scripts/wkb-to-ewkb/main.go

diff --git a/cmd/go_migrate/mssql-transform.go b/cmd/go_migrate/mssql-transform.go
index 930ee2d..9f73468 100644
--- a/cmd/go_migrate/mssql-transform.go
+++ b/cmd/go_migrate/mssql-transform.go
@@ -1,5 +1,9 @@
 package main
 
+import (
+	"encoding/binary"
+)
+
 func mssqlUuidToBigEndian(mssqlUuid []byte) []byte {
 	if len(mssqlUuid) != 16 {
 		return mssqlUuid
@@ -12,3 +16,37 @@ func mssqlUuidToBigEndian(mssqlUuid []byte) []byte {
 
 	return pgUuid
 }
+
+const sridFlag = 0x20000000
+
+func wkbToEwkbWithSrid(geometry []byte, srid int) []byte {
+	if len(geometry) < 5 {
+		return geometry
+	}
+
+	var byteOrder binary.ByteOrder
+	if geometry[0] == 0 {
+		byteOrder = binary.BigEndian
+	} else {
+		byteOrder = binary.LittleEndian
+	}
+
+	wkbType := byteOrder.Uint32(geometry[1:5])
+	if wkbType&sridFlag != 0 {
+		return geometry
+	}
+
+	ewkbType := wkbType | sridFlag
+
+	result := make([]byte, len(geometry)+4)
+
+	result[0] = geometry[0]
+
+	byteOrder.PutUint32(result[1:5], ewkbType)
+
+	byteOrder.PutUint32(result[5:9], uint32(srid))
+
+	copy(result[9:], geometry[5:])
+
+	return result
+}
diff --git a/cmd/go_migrate/process.go b/cmd/go_migrate/process.go
index 01cc1e4..5f49d47 100644
--- a/cmd/go_migrate/process.go
+++ b/cmd/go_migrate/process.go
@@ -79,6 +79,10 @@ func transformRowsMssql(columns []ColumnType, in <-chan []UnknownRowValues, out
 					if b, ok := value.([]byte); ok {
 						rowValues[i] = mssqlUuidToBigEndian(b)
 					}
+				} else if col.SystemType() == "geometry" || col.SystemType() == "geography" {
+					if b, ok := value.([]byte); ok {
+						rowValues[i] = wkbToEwkbWithSrid(b, 4326)
+					}
 				}
 			}
 		}
@@ -90,7 +94,7 @@ func transformRowsMssql(columns []ColumnType, in <-chan []UnknownRowValues, out
 func logSampleRow(job MigrationJob, columns []ColumnType, rowValues UnknownRowValues, tag string) {
 	log.Infof("[%s.%s] Sample row: (%s)", job.Schema, job.Table, tag)
 	for i, col := range columns {
-		log.Infof("%s: %v", col.Name(), rowValues[i])
+		log.Infof("%s (%T): %v", col.Name(), rowValues[i], rowValues[i])
 	}
 }
 
diff --git a/scripts/wkb-to-ewkb/main.go b/scripts/wkb-to-ewkb/main.go
new file mode 100644
index 0000000..81491f3
--- /dev/null
+++ b/scripts/wkb-to-ewkb/main.go
@@ -0,0 +1,59 @@
+package main
+
+import (
+	"encoding/binary"
+	"fmt"
+)
+
+const sridFlag = 0x20000000
+
+func wkbToEwkbWithSrid(geometry []byte, srid int) []byte {
+	if len(geometry) < 5 {
+		return geometry
+	}
+
+	var byteOrder binary.ByteOrder
+	if geometry[0] == 0 {
+		byteOrder = binary.BigEndian
+	} else {
+		byteOrder = binary.LittleEndian
+	}
+
+	wkbType := byteOrder.Uint32(geometry[1:5])
+	if wkbType&sridFlag != 0 {
+		return geometry
+	}
+
+	ewkbType := wkbType | sridFlag
+
+	result := make([]byte, len(geometry)+4)
+
+	result[0] = geometry[0]
+
+	byteOrder.PutUint32(result[1:5], ewkbType)
+
+	byteOrder.PutUint32(result[5:9], uint32(srid))
+
+	copy(result[9:], geometry[5:])
+
+	return result
+}
+
+func main() {
+	shape := []byte{
+		1, 3, 0, 0, 0, 1, 0, 0, 0, 5, 0, 0, 0, 217, 61, 121, 88, 168, 57, 83, 192,
+		60, 78, 209, 145, 92, 222, 39, 192, 232, 106, 43, 246, 151, 57, 83, 192,
+		60, 78, 209, 145, 92, 222, 39, 192, 232, 106, 43, 246, 151, 57, 83, 192,
+		174, 182, 98, 127, 217, 221, 39, 192, 217, 61, 121, 88, 168, 57, 83, 192,
+		174, 182, 98, 127, 217, 221, 39, 192, 217, 61, 121, 88, 168, 57, 83, 192,
+		60, 78, 209, 145, 92, 222, 39, 192,
+	}
+
+	srid := 4326
+	result := wkbToEwkbWithSrid(shape, srid)
+
+	fmt.Printf("WKB Original (len): %d\n", len(shape))
+	fmt.Printf("EWKB Result   (len): %d\n", len(result))
+	fmt.Printf("Primeros bytes (original): %v\n", shape[:10])
+	fmt.Printf("Primeros bytes (resultado): %v\n", result[:10])
+}