From bdf07d84b4c1da18c9ef8d39504698f16a368a51 Mon Sep 17 00:00:00 2001
From: Benoit Simard <contact@bsimard.com>
Date: Thu, 12 Dec 2024 12:39:23 +0100
Subject: [PATCH] editoast: better sql query to split a track section

Fix #8947

New query is not using the `ST_LineSubstring` which gives bad result with geography data that has long segment.
By computing the geo point and doing a split of the TS near this point, it's a lot better.

Signed-off-by: Benoit Simard <contact@bsimard.com>
---
 .../sql/get_split_track_section_with_data.sql | 57 +++++++++++--------
 1 file changed, 32 insertions(+), 25 deletions(-)

diff --git a/editoast/src/models/infra/sql/get_split_track_section_with_data.sql b/editoast/src/models/infra/sql/get_split_track_section_with_data.sql
index 9dc0d2a0707..3926b41f9a8 100644
--- a/editoast/src/models/infra/sql/get_split_track_section_with_data.sql
+++ b/editoast/src/models/infra/sql/get_split_track_section_with_data.sql
@@ -1,27 +1,34 @@
-SELECT object_table.obj_id as obj_id,
-    object_table.data as railjson,
-    ST_AsGeoJSON(
-        ST_Transform(
-            ST_LineSubstring(
-                layer_table.geographic,
-                0,
-                $3
+SELECT 
+    obj_id,
+    railjson,
+	ST_AsGeoJSON( ST_Transform(ST_GeometryN( splitted, 1 ), 4326) )::jsonb as left_geo,
+	ST_AsGeoJSON( ST_Transform(ST_GeometryN( splitted, 2 ), 4326) )::jsonb as right_geo
+FROM (
+    SELECT 
+        obj_id,
+        railjson,
+        ST_SPLIT(
+            ST_Snap(
+                geometry::geometry,
+                geo_split_point::geometry,
+                ST_Distance(geometry::geometry, geo_split_point::geometry)*1.01
             ),
-            4326
+            geo_split_point::geometry
+        ) as splitted
+    FROM 
+        (SELECT
+            object_table.obj_id as obj_id,
+            object_table.data as railjson,
+            ST_Transform(layer_table.geographic, 4326)::geography as geometry,
+            ST_LineInterpolatePoint(
+                ST_Transform(layer_table.geographic, 4326),
+                $3::float,
+                True
+            ) as geo_split_point
+        FROM infra_object_track_section AS object_table
+            LEFT JOIN infra_layer_track_section AS layer_table ON layer_table.infra_id = object_table.infra_id
+            AND object_table.obj_id = layer_table.obj_id
+        WHERE object_table.infra_id = $1
+            AND object_table.obj_id = $2
         )
-    )::jsonb as left_geo,
-    ST_AsGeoJSON(
-        ST_Transform(
-            ST_LineSubstring(
-                layer_table.geographic,
-                $3,
-                1
-            ),
-            4326
-        )
-    )::jsonb as right_geo
-FROM infra_object_track_section AS object_table
-    LEFT JOIN infra_layer_track_section AS layer_table ON layer_table.infra_id = object_table.infra_id
-    AND object_table.obj_id = layer_table.obj_id
-WHERE object_table.infra_id = $1
-    AND object_table.obj_id = $2
+	);