fix: restore fallback machine navigation after deletion

src/client/src/components/PiWebApp.ts

@@ -455,9 +455,9 @@ export class PiWebApp extends LitElement {
     setNamespacedQueryKey(TERMINAL_ROUTE_NAMESPACE, "terminal", surface.selectedTerminalId, { replace: true });
   }
 
-  private async selectMachineWithMemory(machine: Machine): Promise<void> {
+  private async selectMachineWithMemory(machine: Machine, options: { rememberCurrent?: boolean } = {}): Promise<void> {
     if (this.state.selectedMachine?.id === machine.id) return;
-    if (!this.routeRestoreInProgress) this.rememberCurrentMachineNavigation();
+    if (options.rememberCurrent !== false && !this.routeRestoreInProgress) this.rememberCurrentMachineNavigation();
     const seq = ++this.machineNavigationRestoreSeq;
     const snapshot = this.machineNavigation.latest(machine.id) ?? emptyMachineNavigationSnapshot(machine.id);
     await this.restoreRouteFor(routeFromMachineNavigationSnapshot(snapshot), false, snapshot.surface, snapshot.view);
@@ -1044,7 +1044,11 @@ export class PiWebApp extends LitElement {
   private async removeMachine(machine: Machine | undefined = this.state.selectedMachine): Promise<void> {
     if (machine === undefined || machine.kind === "local") return;
     if (!window.confirm(`Remove ${machine.name}?\n\nThis only removes it from this PI WEB gateway.`)) return;
-    await this.machines.deleteMachine(machine);
+    const wasSelected = this.state.selectedMachine?.id === machine.id;
+    if (wasSelected) this.rememberCurrentMachineNavigation();
+    const fallback = await this.machines.deleteMachine(machine, { selectFallback: !wasSelected });
+    if (!this.state.machines.some((candidate) => candidate.id === machine.id)) this.machineNavigation.forget(machine.id);
+    if (wasSelected && fallback !== undefined) await this.selectMachineWithMemory(fallback, { rememberCurrent: false });
   }
 
   private openSelectedMachine(): void {

src/client/src/controllers/machineController.test.ts

@@ -72,4 +72,42 @@ describe("MachineController", () => {
     expect(state.machineStatuses[remoteMachine.id]).toMatchObject({ machineId: remoteMachine.id, ok: false, status: "offline", error: "Internal Server Error" });
     expect(state.error).toContain("Remote is offline");
   });
+
+  it("returns the fallback machine without selecting it when requested", async () => {
+    let state: AppState = { ...initialAppState(), machines: [localMachine, remoteMachine], selectedMachine: remoteMachine };
+    const setState = (patch: Partial<AppState>) => { state = { ...state, ...patch }; };
+    const updateUrl = vi.fn();
+    const projects = { loadProjects: vi.fn() };
+
+    vi.spyOn(api, "deleteMachine").mockResolvedValue({ deleted: true });
+
+    const controller = new MachineController(() => state, setState, updateUrl, projects);
+
+    const fallback = await controller.deleteMachine(remoteMachine, { selectFallback: false });
+
+    expect(fallback).toEqual(localMachine);
+    expect(state.machines).toEqual([localMachine]);
+    expect(state.selectedMachine).toEqual(remoteMachine);
+    expect(projects.loadProjects).not.toHaveBeenCalled();
+    expect(updateUrl).not.toHaveBeenCalled();
+  });
+
+  it("selects the fallback machine after deleting the selected machine by default", async () => {
+    let state: AppState = { ...initialAppState(), machines: [localMachine, remoteMachine], selectedMachine: remoteMachine, selectedProject: { id: "p1", name: "Project", path: "/repo", createdAt: "now" } };
+    const setState = (patch: Partial<AppState>) => { state = { ...state, ...patch }; };
+    const updateUrl = vi.fn();
+    const projects = { loadProjects: vi.fn() };
+
+    vi.spyOn(api, "deleteMachine").mockResolvedValue({ deleted: true });
+
+    const controller = new MachineController(() => state, setState, updateUrl, projects);
+
+    const fallback = await controller.deleteMachine(remoteMachine);
+
+    expect(fallback).toEqual(localMachine);
+    expect(state.selectedMachine).toEqual(localMachine);
+    expect(state.selectedProject).toBeUndefined();
+    expect(projects.loadProjects).toHaveBeenCalledOnce();
+    expect(updateUrl).toHaveBeenCalledOnce();
+  });
 });

src/client/src/controllers/machineController.ts

@@ -59,20 +59,27 @@ export class MachineController {
     }
   }
 
-  async deleteMachine(machine: Machine | undefined = this.getState().selectedMachine): Promise<void> {
-    if (machine === undefined) return;
+  async deleteMachine(machine: Machine | undefined = this.getState().selectedMachine, options: { selectFallback?: boolean } = {}): Promise<Machine | undefined> {
+    if (machine === undefined) return undefined;
     if (machine.kind === "local") {
       this.setState({ error: "The local machine cannot be removed." });
-      return;
+      return undefined;
     }
     try {
+      const wasSelected = this.getState().selectedMachine?.id === machine.id;
       await api.deleteMachine(machine.id);
       const machines = this.getState().machines.filter((candidate) => candidate.id !== machine.id);
       const local = machines.find((candidate) => candidate.id === "local") ?? machines[0];
       this.setState({ machines, machineStatuses: omitKey(this.getState().machineStatuses, machine.id) });
-      if (this.getState().selectedMachine?.id === machine.id && local !== undefined) await this.selectMachine(local);
+      if (wasSelected && local !== undefined) {
+        if (options.selectFallback === false) return local;
+        await this.selectMachine(local);
+        return local;
+      }
+      return undefined;
     } catch (error) {
       this.setState({ error: String(error) });
+      return undefined;
     }
   }