bug(web): Inform user when deleted topology is still used

This change fixes #135 which showed that trying to delete a topology
used by a scenario would result in nothing happening in the UI and a 500
error being returned by the server. We check whether a scenario still
references the topology and show an error to the user if that happens.

Fixes #135

5 files changed, 93 insertions, 43 deletions

diff --git a/opendc-web/opendc-web-server/src/main/java/org/opendc/web/server/rest/user/TopologyResource.java b/opendc-web/opendc-web-server/src/main/java/org/opendc/web/server/rest/user/TopologyResource.java
index 2b66b64b..71491801 100644
--- a/opendc-web/opendc-web-server/src/main/java/org/opendc/web/server/rest/user/TopologyResource.java
+++ b/opendc-web/opendc-web-server/src/main/java/org/opendc/web/server/rest/user/TopologyResource.java
@@ -22,10 +22,12 @@
 
 package org.opendc.web.server.rest.user;
 
+import io.quarkus.hibernate.orm.panache.Panache;
 import io.quarkus.security.identity.SecurityIdentity;
 import java.time.Instant;
 import java.util.List;
 import javax.annotation.security.RolesAllowed;
+import javax.persistence.PersistenceException;
 import javax.transaction.Transactional;
 import javax.validation.Valid;
 import javax.ws.rs.Consumes;
@@ -193,6 +195,14 @@ public final class TopologyResource {
 
         entity.updatedAt = Instant.now();
         entity.delete();
+
+        try {
+            // Flush the results, so we can check whether the constraints are not violated
+            Panache.flush();
+        } catch (PersistenceException e) {
+            throw new WebApplicationException("Topology is still in use", 403);
+        }
+
         return UserProtocol.toDto(entity, auth);
     }
 }
diff --git a/opendc-web/opendc-web-server/src/test/java/org/opendc/web/server/rest/user/TopologyResourceTest.java b/opendc-web/opendc-web-server/src/test/java/org/opendc/web/server/rest/user/TopologyResourceTest.java
index 21e35b09..c0746e7a 100644
--- a/opendc-web/opendc-web-server/src/test/java/org/opendc/web/server/rest/user/TopologyResourceTest.java
+++ b/opendc-web/opendc-web-server/src/test/java/org/opendc/web/server/rest/user/TopologyResourceTest.java
@@ -355,4 +355,20 @@ public final class TopologyResourceTest {
                 .statusCode(200)
                 .contentType(ContentType.JSON);
     }
+
+    /**
+     * Test to delete a topology that is still being used by a scenario.
+     */
+    @Test
+    @TestSecurity(
+            user = "owner",
+            roles = {"openid"})
+    public void testDeleteUsed() {
+        given().pathParam("project", "1")
+                .when()
+                .delete("/1") // Topology 1 is still used by scenario 1 and 2
+                .then()
+                .statusCode(403)
+                .contentType(ContentType.JSON);
+    }
 }
diff --git a/opendc-web/opendc-web-ui/src/api/index.js b/opendc-web/opendc-web-ui/src/api/index.js
index 75751658..3411b96e 100644
--- a/opendc-web/opendc-web-ui/src/api/index.js
+++ b/opendc-web/opendc-web-ui/src/api/index.js
@@ -49,7 +49,7 @@ export async function request(auth, path, method = 'GET', body) {
     const json = await response.json()
 
     if (!response.ok) {
-        throw response.message
+        throw json.message
     }
 
     return json
diff --git a/opendc-web/opendc-web-ui/src/components/projects/TopologyTable.js b/opendc-web/opendc-web-ui/src/components/projects/TopologyTable.js
index 62deace0..1c2c4f04 100644
--- a/opendc-web/opendc-web-ui/src/components/projects/TopologyTable.js
+++ b/opendc-web/opendc-web-ui/src/components/projects/TopologyTable.js
@@ -20,18 +20,22 @@
  * SOFTWARE.
  */
 
-import { Bullseye } from '@patternfly/react-core'
+import { Bullseye, AlertGroup, Alert, AlertVariant, AlertActionCloseButton } from '@patternfly/react-core'
 import PropTypes from 'prop-types'
 import Link from 'next/link'
 import { Tr, Th, Thead, Td, ActionsColumn, Tbody, TableComposable } from '@patternfly/react-table'
-import React from 'react'
+import React, { useState } from 'react'
 import TableEmptyState from '../util/TableEmptyState'
 import { parseAndFormatDateTime } from '../../util/date-time'
 import { useTopologies, useDeleteTopology } from '../../data/topology'
 
 function TopologyTable({ projectId }) {
+    const [error, setError] = useState('')
+
     const { status, data: topologies = [] } = useTopologies(projectId)
-    const { mutate: deleteTopology } = useDeleteTopology()
+    const { mutate: deleteTopology } = useDeleteTopology({
+        onError: (error) => setError(error),
+    })
 
     const actions = ({ number }) => [
         {
@@ -42,45 +46,65 @@ function TopologyTable({ projectId }) {
     ]
 
     return (
-        <TableComposable aria-label="Topology List" variant="compact">
-            <Thead>
-                <Tr>
-                    <Th>Name</Th>
-                    <Th>Rooms</Th>
-                    <Th>Last Edited</Th>
-                </Tr>
-            </Thead>
-            <Tbody>
-                {topologies.map((topology) => (
-                    <Tr key={topology.id}>
-                        <Td dataLabel="Name">
-                            <Link href={`/projects/${projectId}/topologies/${topology.number}`}>{topology.name}</Link>
-                        </Td>
-                        <Td dataLabel="Rooms">
-                            {topology.rooms.length === 1 ? '1 room' : `${topology.rooms.length} rooms`}
-                        </Td>
-                        <Td dataLabel="Last Edited">{parseAndFormatDateTime(topology.updatedAt)}</Td>
-                        <Td isActionCell>
-                            <ActionsColumn items={actions(topology)} />
-                        </Td>
-                    </Tr>
-                ))}
-                {topologies.length === 0 && (
+        <>
+            <AlertGroup isToast>
+                {error && (
+                    <Alert
+                        isLiveRegion
+                        variant={AlertVariant.danger}
+                        title={error}
+                        actionClose={
+                            <AlertActionCloseButton
+                                title={error}
+                                variantLabel="danger alert"
+                                onClose={() => setError(null)}
+                            />
+                        }
+                    />
+                )}
+            </AlertGroup>
+            <TableComposable aria-label="Topology List" variant="compact">
+                <Thead>
                     <Tr>
-                        <Td colSpan={3}>
-                            <Bullseye>
-                                <TableEmptyState
-                                    status={status}
-                                    loadingTitle="Loading topologies"
-                                    emptyTitle="No topologies"
-                                    emptyText="You have not created any topology for this project yet. Click the New Topology button to create one."
-                                />
-                            </Bullseye>
-                        </Td>
+                        <Th>Name</Th>
+                        <Th>Rooms</Th>
+                        <Th>Last Edited</Th>
                     </Tr>
-                )}
-            </Tbody>
-        </TableComposable>
+                </Thead>
+                <Tbody>
+                    {topologies.map((topology) => (
+                        <Tr key={topology.id}>
+                            <Td dataLabel="Name">
+                                <Link href={`/projects/${projectId}/topologies/${topology.number}`}>
+                                    {topology.name}
+                                </Link>
+                            </Td>
+                            <Td dataLabel="Rooms">
+                                {topology.rooms.length === 1 ? '1 room' : `${topology.rooms.length} rooms`}
+                            </Td>
+                            <Td dataLabel="Last Edited">{parseAndFormatDateTime(topology.updatedAt)}</Td>
+                            <Td isActionCell>
+                                <ActionsColumn items={actions(topology)} />
+                            </Td>
+                        </Tr>
+                    ))}
+                    {topologies.length === 0 && (
+                        <Tr>
+                            <Td colSpan={3}>
+                                <Bullseye>
+                                    <TableEmptyState
+                                        status={status}
+                                        loadingTitle="Loading topologies"
+                                        emptyTitle="No topologies"
+                                        emptyText="You have not created any topology for this project yet. Click the New Topology button to create one."
+                                    />
+                                </Bullseye>
+                            </Td>
+                        </Tr>
+                    )}
+                </Tbody>
+            </TableComposable>
+        </>
     )
 }
 
diff --git a/opendc-web/opendc-web-ui/src/data/topology.js b/opendc-web/opendc-web-ui/src/data/topology.js
index ac6cabe5..d5e624d5 100644
--- a/opendc-web/opendc-web-ui/src/data/topology.js
+++ b/opendc-web/opendc-web-ui/src/data/topology.js
@@ -83,6 +83,6 @@ export function useNewTopology() {
 /**
  * Create a mutation for deleting a topology.
  */
-export function useDeleteTopology() {
-    return useMutation('deleteTopology')
+export function useDeleteTopology(options = {}) {
+    return useMutation('deleteTopology', options)
 }