From ad479bdcf2cdd74bdd7cc86590bc820cda4e4aeb Mon Sep 17 00:00:00 2001
From: Marshal <marshal@example.com>
Date: Wed, 19 Aug 2026 10:10:04 +0000
Subject: [PATCH] issue fix

---
 .../modules/trains/train-builder.service.ts   | 63 ++++++++++++++++---
 1 file changed, 53 insertions(+), 10 deletions(-)

diff --git a/apps/edr-freight-api/src/modules/trains/train-builder.service.ts b/apps/edr-freight-api/src/modules/trains/train-builder.service.ts
index a27944c3e..827596bb7 100644
--- a/apps/edr-freight-api/src/modules/trains/train-builder.service.ts
+++ b/apps/edr-freight-api/src/modules/trains/train-builder.service.ts
@@ -577,11 +577,7 @@ export class TrainBuilderService {
       if (!wagon || wagon.trainId !== train.id) {
         throw new NotFoundException(`Wagon ${wagonId} is not part of this train`);
       }
-      if (await this.isWagonPinnedToLiveSchedule(manager, wagon.id)) {
-        throw new ConflictException(
-          `Wagon ${wagon.wagonNumber} is pinned to an active schedule and cannot be removed`,
-        );
-      }
+      await this.assertDetachableAndReleaseStaleSlots(manager, wagon);
       await manager.getRepository(Wagon).update(wagon.id, {
         trainId: null,
         sequenceNumber: null,
@@ -618,11 +614,7 @@ export class TrainBuilderService {
       if (!wagon || wagon.trainId !== train.id) {
         throw new NotFoundException(`Wagon ${wagonId} is not part of this train`);
       }
-      if (await this.isWagonPinnedToLiveSchedule(manager, wagon.id)) {
-        throw new ConflictException(
-          `Wagon ${wagon.wagonNumber} is pinned to an active schedule and cannot be removed`,
-        );
-      }
+      await this.assertDetachableAndReleaseStaleSlots(manager, wagon);
       const previousStatus = wagon.status;
       const notes = buildMaintenanceNotes(formatTrainRunLabel(train), note);
       await manager.getRepository(Wagon).update(wagon.id, {
@@ -705,6 +697,57 @@ export class TrainBuilderService {
     return rows.length > 0;
   }
 
+  /**
+   * Detach guard for removeWagon / sendWagonToMaintenance. A wagon is truly
+   * pinned only while a live schedule still NEEDS it: a slot carrying booking
+   * allocations, or any slot on a DISPATCHED run. An empty (allocation-free)
+   * slot on a DRAFT/SCHEDULED schedule is a stale reservation — its load was
+   * moved to another wagon (moveWagonLoad keeps the emptied slot) or its
+   * booking left through a path that didn't clean up — and used to pin the
+   * wagon forever. Release those slots here instead of blocking, with the
+   * same recount removeTrainSetWagonSlot does (wagonCount / totalLengthMeters
+   * feed the schedule capacity math).
+   */
+  private async assertDetachableAndReleaseStaleSlots(
+    manager: EntityManager,
+    wagon: Wagon,
+  ): Promise<void> {
+    const rows: { id: string; train_set_id: string; status: string; allocs: string }[] =
+      await manager.query(
+        `SELECT tsw.id, tsw.train_set_id, ts.status,
+                (SELECT count(*)
+                   FROM freight.wagon_booking_allocations a
+                  WHERE a.train_set_wagon_id = tsw.id
+                    AND a.deleted_at IS NULL) AS allocs
+           FROM freight.train_set_wagons tsw
+           JOIN freight.train_schedules ts ON ts.train_set_id = tsw.train_set_id
+          WHERE tsw.physical_wagon_id = $1
+            AND ts.status IN ('DRAFT', 'SCHEDULED', 'DISPATCHED')
+            AND ts.deleted_at IS NULL
+            AND tsw.deleted_at IS NULL`,
+        [wagon.id],
+      );
+    if (!rows.length) return;
+    if (rows.some((r) => Number(r.allocs) > 0 || r.status === 'DISPATCHED')) {
+      throw new ConflictException(
+        `Wagon ${wagon.wagonNumber} is pinned to an active schedule and cannot be removed`,
+      );
+    }
+    await manager.getRepository(TrainSetWagon).delete(rows.map((r) => r.id));
+    for (const trainSetId of [...new Set(rows.map((r) => r.train_set_id))]) {
+      const remaining = await manager.getRepository(TrainSetWagon).find({
+        where: { trainSetId },
+        select: { id: true, lengthMeters: true },
+      });
+      await manager.getRepository(TrainSet).update(trainSetId, {
+        wagonCount: remaining.length,
+        totalLengthMeters: round(
+          remaining.reduce((sum, w) => sum + (Number(w.lengthMeters) || 0), 0),
+        ),
+      });
+    }
+  }
+
   /** Persist a drag-reorder: `wagonIds` is the full consist in its new order. */
   async reorderWagons(id: string, dto: ReorderTrainWagonsDto) {
     await this.dataSource.transaction(async (manager) => {