fix(navigation): back button on host detail returns to application when coming from there

- application_detail: host links now include ?back=/applications/:id
- host_detail: back_label handles /applications/ prefix → "← Application"

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

seeds/postgres/dev_seed.sql

@@ -64,31 +64,41 @@ WHERE NOT EXISTS (SELECT 1 FROM hosts WHERE hosts.name = t.name AND hosts.ip = t
 -- ── Ports catalog ─────────────────────────────────────────────────────────────
 
 INSERT INTO ports (number, description) VALUES
-    (22,   'SSH'),
-    (25,   'SMTP'),
-    (53,   'DNS'),
-    (80,   'HTTP'),
-    (143,  'IMAP'),
-    (161,  'SNMP'),
-    (443,  'HTTPS'),
-    (445,  'SMB'),
-    (465,  'SMTPS'),
-    (500,  'IKE / IPSec'),
-    (514,  'Syslog'),
-    (587,  'SMTP Submission'),
-    (873,  'rsync'),
-    (993,  'IMAPS'),
-    (1194, 'OpenVPN'),
-    (2049, 'NFS'),
-    (3000, 'Grafana'),
-    (3389, 'RDP'),
-    (4500, 'IPSec NAT-T'),
-    (5044, 'Logstash Beats'),
-    (5432, 'PostgreSQL'),
-    (5601, 'Kibana'),
-    (9090, 'Prometheus'),
-    (9100, 'JetDirect'),
-    (9200, 'Elasticsearch')
+    (22,    'SSH'),
+    (25,    'SMTP'),
+    (53,    'DNS'),
+    (80,    'HTTP'),
+    (143,   'IMAP'),
+    (161,   'SNMP'),
+    (443,   'HTTPS'),
+    (445,   'SMB'),
+    (465,   'SMTPS'),
+    (500,   'IKE / IPSec'),
+    (514,   'Syslog'),
+    (587,   'SMTP Submission'),
+    (873,   'rsync'),
+    (993,   'IMAPS'),
+    (1194,  'OpenVPN'),
+    (2049,  'NFS'),
+    (3000,  'Grafana / Gitea'),
+    (3306,  'MariaDB / MySQL'),
+    (3389,  'RDP'),
+    (4500,  'IPSec NAT-T'),
+    (5044,  'Logstash Beats'),
+    (5432,  'PostgreSQL'),
+    (5601,  'Kibana'),
+    (6379,  'Redis'),
+    (8096,  'Jellyfin'),
+    (8123,  'Home Assistant'),
+    (8384,  'Syncthing UI'),
+    (8920,  'Jellyfin HTTPS'),
+    (9000,  'Portainer'),
+    (9090,  'Prometheus'),
+    (9100,  'node_exporter / JetDirect'),
+    (9200,  'Elasticsearch'),
+    (9443,  'Portainer HTTPS'),
+    (22000, 'Syncthing'),
+    (51820, 'WireGuard')
 ON CONFLICT (number) DO NOTHING;
 
 -- ── Host ports ────────────────────────────────────────────────────────────────
@@ -193,3 +203,84 @@ INSERT INTO host_ports (host_id, port_number)
 SELECT h.id, 22 FROM hosts h
 WHERE h.name = 'vpn-client-02' AND h.ip = '172.16.1.11'
 ON CONFLICT DO NOTHING;
+
+-- ── Applications ──────────────────────────────────────────────────────────────
+-- applications has no UNIQUE constraint on name, so we use WHERE NOT EXISTS.
+
+INSERT INTO applications (name)
+SELECT v.name FROM (VALUES
+    ('Nginx'),
+    ('Pi-hole'),
+    ('WireGuard'),
+    ('OpenVPN'),
+    ('PostgreSQL'),
+    ('MariaDB'),
+    ('Redis'),
+    ('Grafana'),
+    ('Prometheus'),
+    ('Elasticsearch'),
+    ('Kibana'),
+    ('Portainer'),
+    ('Jellyfin'),
+    ('Home Assistant'),
+    ('Syncthing'),
+    ('Vaultwarden')
+) AS v(name)
+WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = v.name);
+
+-- ── Application ports ─────────────────────────────────────────────────────────
+
+-- Nginx: HTTP, HTTPS
+INSERT INTO application_ports (application_id, port_number) SELECT id, 80  FROM applications WHERE name = 'Nginx' ON CONFLICT DO NOTHING;
+INSERT INTO application_ports (application_id, port_number) SELECT id, 443 FROM applications WHERE name = 'Nginx' ON CONFLICT DO NOTHING;
+
+-- Pi-hole: DNS, HTTP (admin UI), HTTPS
+INSERT INTO application_ports (application_id, port_number) SELECT id, 53  FROM applications WHERE name = 'Pi-hole' ON CONFLICT DO NOTHING;
+INSERT INTO application_ports (application_id, port_number) SELECT id, 80  FROM applications WHERE name = 'Pi-hole' ON CONFLICT DO NOTHING;
+INSERT INTO application_ports (application_id, port_number) SELECT id, 443 FROM applications WHERE name = 'Pi-hole' ON CONFLICT DO NOTHING;
+
+-- WireGuard
+INSERT INTO application_ports (application_id, port_number) SELECT id, 51820 FROM applications WHERE name = 'WireGuard' ON CONFLICT DO NOTHING;
+
+-- OpenVPN
+INSERT INTO application_ports (application_id, port_number) SELECT id, 1194 FROM applications WHERE name = 'OpenVPN' ON CONFLICT DO NOTHING;
+
+-- PostgreSQL
+INSERT INTO application_ports (application_id, port_number) SELECT id, 5432 FROM applications WHERE name = 'PostgreSQL' ON CONFLICT DO NOTHING;
+
+-- MariaDB
+INSERT INTO application_ports (application_id, port_number) SELECT id, 3306 FROM applications WHERE name = 'MariaDB' ON CONFLICT DO NOTHING;
+
+-- Redis
+INSERT INTO application_ports (application_id, port_number) SELECT id, 6379 FROM applications WHERE name = 'Redis' ON CONFLICT DO NOTHING;
+
+-- Grafana
+INSERT INTO application_ports (application_id, port_number) SELECT id, 3000 FROM applications WHERE name = 'Grafana' ON CONFLICT DO NOTHING;
+
+-- Prometheus
+INSERT INTO application_ports (application_id, port_number) SELECT id, 9090 FROM applications WHERE name = 'Prometheus' ON CONFLICT DO NOTHING;
+
+-- Elasticsearch
+INSERT INTO application_ports (application_id, port_number) SELECT id, 9200 FROM applications WHERE name = 'Elasticsearch' ON CONFLICT DO NOTHING;
+
+-- Kibana
+INSERT INTO application_ports (application_id, port_number) SELECT id, 5601 FROM applications WHERE name = 'Kibana' ON CONFLICT DO NOTHING;
+
+-- Portainer: HTTP, HTTPS
+INSERT INTO application_ports (application_id, port_number) SELECT id, 9000 FROM applications WHERE name = 'Portainer' ON CONFLICT DO NOTHING;
+INSERT INTO application_ports (application_id, port_number) SELECT id, 9443 FROM applications WHERE name = 'Portainer' ON CONFLICT DO NOTHING;
+
+-- Jellyfin: HTTP, HTTPS
+INSERT INTO application_ports (application_id, port_number) SELECT id, 8096 FROM applications WHERE name = 'Jellyfin' ON CONFLICT DO NOTHING;
+INSERT INTO application_ports (application_id, port_number) SELECT id, 8920 FROM applications WHERE name = 'Jellyfin' ON CONFLICT DO NOTHING;
+
+-- Home Assistant
+INSERT INTO application_ports (application_id, port_number) SELECT id, 8123 FROM applications WHERE name = 'Home Assistant' ON CONFLICT DO NOTHING;
+
+-- Syncthing: UI, data sync
+INSERT INTO application_ports (application_id, port_number) SELECT id, 8384  FROM applications WHERE name = 'Syncthing' ON CONFLICT DO NOTHING;
+INSERT INTO application_ports (application_id, port_number) SELECT id, 22000 FROM applications WHERE name = 'Syncthing' ON CONFLICT DO NOTHING;
+
+-- Vaultwarden: HTTP, HTTPS
+INSERT INTO application_ports (application_id, port_number) SELECT id, 80  FROM applications WHERE name = 'Vaultwarden' ON CONFLICT DO NOTHING;
+INSERT INTO application_ports (application_id, port_number) SELECT id, 443 FROM applications WHERE name = 'Vaultwarden' ON CONFLICT DO NOTHING;

seeds/sqlite/dev_seed.sql

@@ -44,31 +44,41 @@ INSERT INTO hosts (name, ip, network_id) SELECT 'vpn-client-02',  '172.16.1.11',
 -- ── Ports catalog ─────────────────────────────────────────────────────────────
 
 INSERT OR IGNORE INTO ports (number, description) VALUES
-    (22,   'SSH'),
-    (25,   'SMTP'),
-    (53,   'DNS'),
-    (80,   'HTTP'),
-    (143,  'IMAP'),
-    (161,  'SNMP'),
-    (443,  'HTTPS'),
-    (445,  'SMB'),
-    (465,  'SMTPS'),
-    (500,  'IKE / IPSec'),
-    (514,  'Syslog'),
-    (587,  'SMTP Submission'),
-    (873,  'rsync'),
-    (993,  'IMAPS'),
-    (1194, 'OpenVPN'),
-    (2049, 'NFS'),
-    (3000, 'Grafana'),
-    (3389, 'RDP'),
-    (4500, 'IPSec NAT-T'),
-    (5044, 'Logstash Beats'),
-    (5432, 'PostgreSQL'),
-    (5601, 'Kibana'),
-    (9090, 'Prometheus'),
-    (9100, 'JetDirect'),
-    (9200, 'Elasticsearch');
+    (22,    'SSH'),
+    (25,    'SMTP'),
+    (53,    'DNS'),
+    (80,    'HTTP'),
+    (143,   'IMAP'),
+    (161,   'SNMP'),
+    (443,   'HTTPS'),
+    (445,   'SMB'),
+    (465,   'SMTPS'),
+    (500,   'IKE / IPSec'),
+    (514,   'Syslog'),
+    (587,   'SMTP Submission'),
+    (873,   'rsync'),
+    (993,   'IMAPS'),
+    (1194,  'OpenVPN'),
+    (2049,  'NFS'),
+    (3000,  'Grafana / Gitea'),
+    (3306,  'MariaDB / MySQL'),
+    (3389,  'RDP'),
+    (4500,  'IPSec NAT-T'),
+    (5044,  'Logstash Beats'),
+    (5432,  'PostgreSQL'),
+    (5601,  'Kibana'),
+    (6379,  'Redis'),
+    (8096,  'Jellyfin'),
+    (8123,  'Home Assistant'),
+    (8384,  'Syncthing UI'),
+    (8920,  'Jellyfin HTTPS'),
+    (9000,  'Portainer'),
+    (9090,  'Prometheus'),
+    (9100,  'node_exporter / JetDirect'),
+    (9200,  'Elasticsearch'),
+    (9443,  'Portainer HTTPS'),
+    (22000, 'Syncthing'),
+    (51820, 'WireGuard');
 
 -- ── Host ports ────────────────────────────────────────────────────────────────
 -- INSERT OR IGNORE is safe: host_ports has a composite PRIMARY KEY (host_id, port_number).
@@ -124,7 +134,7 @@ INSERT OR IGNORE INTO host_ports (host_id, port_number) SELECT id, 993 FROM host
 INSERT OR IGNORE INTO host_ports (host_id, port_number) SELECT id, 22  FROM hosts WHERE name = 'core-switch-01'   AND ip = '10.0.0.1';
 INSERT OR IGNORE INTO host_ports (host_id, port_number) SELECT id, 161 FROM hosts WHERE name = 'core-switch-01'   AND ip = '10.0.0.1';
 
--- monitoring-01: SSH, HTTP, HTTPS, Prometheus, Grafana
+-- monitoring-01: SSH, HTTP, HTTPS, Grafana, Prometheus
 INSERT OR IGNORE INTO host_ports (host_id, port_number) SELECT id, 22   FROM hosts WHERE name = 'monitoring-01'    AND ip = '10.0.1.10';
 INSERT OR IGNORE INTO host_ports (host_id, port_number) SELECT id, 80   FROM hosts WHERE name = 'monitoring-01'    AND ip = '10.0.1.10';
 INSERT OR IGNORE INTO host_ports (host_id, port_number) SELECT id, 443  FROM hosts WHERE name = 'monitoring-01'    AND ip = '10.0.1.10';
@@ -152,3 +162,81 @@ INSERT OR IGNORE INTO host_ports (host_id, port_number) SELECT id, 4500 FROM hos
 -- vpn clients: SSH only
 INSERT OR IGNORE INTO host_ports (host_id, port_number) SELECT id, 22 FROM hosts WHERE name = 'vpn-client-01'  AND ip = '172.16.1.10';
 INSERT OR IGNORE INTO host_ports (host_id, port_number) SELECT id, 22 FROM hosts WHERE name = 'vpn-client-02'  AND ip = '172.16.1.11';
+
+-- ── Applications ──────────────────────────────────────────────────────────────
+-- applications has no UNIQUE constraint on name, so we use WHERE NOT EXISTS.
+
+INSERT INTO applications (name) SELECT 'Nginx'          WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = 'Nginx');
+INSERT INTO applications (name) SELECT 'Pi-hole'        WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = 'Pi-hole');
+INSERT INTO applications (name) SELECT 'WireGuard'      WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = 'WireGuard');
+INSERT INTO applications (name) SELECT 'OpenVPN'        WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = 'OpenVPN');
+INSERT INTO applications (name) SELECT 'PostgreSQL'     WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = 'PostgreSQL');
+INSERT INTO applications (name) SELECT 'MariaDB'        WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = 'MariaDB');
+INSERT INTO applications (name) SELECT 'Redis'          WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = 'Redis');
+INSERT INTO applications (name) SELECT 'Grafana'        WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = 'Grafana');
+INSERT INTO applications (name) SELECT 'Prometheus'     WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = 'Prometheus');
+INSERT INTO applications (name) SELECT 'Elasticsearch'  WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = 'Elasticsearch');
+INSERT INTO applications (name) SELECT 'Kibana'         WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = 'Kibana');
+INSERT INTO applications (name) SELECT 'Portainer'      WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = 'Portainer');
+INSERT INTO applications (name) SELECT 'Jellyfin'       WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = 'Jellyfin');
+INSERT INTO applications (name) SELECT 'Home Assistant' WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = 'Home Assistant');
+INSERT INTO applications (name) SELECT 'Syncthing'      WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = 'Syncthing');
+INSERT INTO applications (name) SELECT 'Vaultwarden'    WHERE NOT EXISTS (SELECT 1 FROM applications WHERE name = 'Vaultwarden');
+
+-- ── Application ports ─────────────────────────────────────────────────────────
+-- application_ports has a composite PRIMARY KEY, so INSERT OR IGNORE is safe.
+
+-- Nginx: HTTP, HTTPS
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 80  FROM applications WHERE name = 'Nginx';
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 443 FROM applications WHERE name = 'Nginx';
+
+-- Pi-hole: DNS, HTTP (admin UI), HTTPS
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 53  FROM applications WHERE name = 'Pi-hole';
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 80  FROM applications WHERE name = 'Pi-hole';
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 443 FROM applications WHERE name = 'Pi-hole';
+
+-- WireGuard
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 51820 FROM applications WHERE name = 'WireGuard';
+
+-- OpenVPN
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 1194 FROM applications WHERE name = 'OpenVPN';
+
+-- PostgreSQL
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 5432 FROM applications WHERE name = 'PostgreSQL';
+
+-- MariaDB
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 3306 FROM applications WHERE name = 'MariaDB';
+
+-- Redis
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 6379 FROM applications WHERE name = 'Redis';
+
+-- Grafana
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 3000 FROM applications WHERE name = 'Grafana';
+
+-- Prometheus
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 9090 FROM applications WHERE name = 'Prometheus';
+
+-- Elasticsearch
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 9200 FROM applications WHERE name = 'Elasticsearch';
+
+-- Kibana
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 5601 FROM applications WHERE name = 'Kibana';
+
+-- Portainer: HTTP, HTTPS
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 9000 FROM applications WHERE name = 'Portainer';
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 9443 FROM applications WHERE name = 'Portainer';
+
+-- Jellyfin: HTTP, HTTPS
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 8096 FROM applications WHERE name = 'Jellyfin';
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 8920 FROM applications WHERE name = 'Jellyfin';
+
+-- Home Assistant
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 8123 FROM applications WHERE name = 'Home Assistant';
+
+-- Syncthing: UI, data sync
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 8384  FROM applications WHERE name = 'Syncthing';
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 22000 FROM applications WHERE name = 'Syncthing';
+
+-- Vaultwarden: HTTP, HTTPS
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 80  FROM applications WHERE name = 'Vaultwarden';
+INSERT OR IGNORE INTO application_ports (application_id, port_number) SELECT id, 443 FROM applications WHERE name = 'Vaultwarden';

src/api/applications.rs

@@ -5,6 +5,24 @@ use serde::{Deserialize, Serialize};
 
 use crate::models::Application;
 
+// Minimal host reference used by ApplicationDetail.
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct HostRef {
+    pub id:   i64,
+    pub name: String,
+    pub ip:   String,
+}
+
+// Full detail for a single application: identity, associated ports, and linked hosts.
+// Linked hosts are those that have at least one port matching an application_ports entry.
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct ApplicationDetail {
+    pub id:    i64,
+    pub name:  String,
+    pub ports: Vec<u16>,
+    pub hosts: Vec<HostRef>,
+}
+
 // Application row enriched with the number of hosts that use at least one of
 // its registered ports.  Host count is computed via the join:
 //   application_ports → host_ports (matched on port_number) → hosts
@@ -65,6 +83,52 @@ pub async fn get_applications() -> Result<Vec<Application>, ServerFnError> {
         .map_err(|e| ServerFnError::new(e.to_string()))
 }
 
+/// Returns full detail for a single application: identity, ports, and linked hosts.
+///
+/// Linked hosts are hosts that have at least one open port matching one of
+/// the application's registered port numbers (via application_ports ↔ host_ports).
+#[server]
+pub async fn get_application_detail(id: i64) -> Result<ApplicationDetail, ServerFnError> {
+    use sqlx::{AnyPool, Row};
+    use crate::server::repository::applications as repo;
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    let app = repo::find_application(&pool, id)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))?
+        .ok_or_else(|| ServerFnError::new(format!("Application {id} not found")))?;
+
+    let ports = repo::list_ports_for_application(&pool, id)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))?;
+
+    let rows = sqlx::query(
+        "SELECT DISTINCT h.id, h.name, h.ip
+         FROM hosts h
+         JOIN host_ports hp        ON hp.host_id    = h.id
+         JOIN application_ports ap ON ap.port_number = hp.port_number
+         WHERE ap.application_id = $1
+         ORDER BY h.name",
+    )
+    .bind(id)
+    .fetch_all(&pool)
+    .await
+    .map_err(|e| ServerFnError::new(e.to_string()))?;
+
+    let hosts = rows
+        .iter()
+        .map(|row| HostRef {
+            id:   row.get("id"),
+            name: row.get("name"),
+            ip:   row.get("ip"),
+        })
+        .collect();
+
+    Ok(ApplicationDetail { id: app.id, name: app.name, ports, hosts })
+}
+
 /// Returns the port numbers associated with an application.
 #[server]
 pub async fn get_ports_for_application(
@@ -83,20 +147,55 @@ pub async fn get_ports_for_application(
 
 // ─── Mutations ────────────────────────────────────────────────────────────────
 
-/// Creates a new application and returns the created record.
+/// Updates the name of an application and returns the updated record.
 #[server]
-pub async fn create_application(name: String) -> Result<Application, ServerFnError> {
+pub async fn update_application(id: i64, name: String) -> Result<Application, ServerFnError> {
     use sqlx::AnyPool;
     use crate::server::repository::applications as repo;
 
     let pool = use_context::<AnyPool>()
         .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
 
-    repo::create_application(&pool, &name)
+    if name.trim().is_empty() {
+        return Err(ServerFnError::new("Application name cannot be empty"));
+    }
+
+    repo::update_application(&pool, id, name.trim())
         .await
         .map_err(|e| ServerFnError::new(e.to_string()))
 }
 
+/// Creates a new application, then associates the given port numbers.
+///
+/// `ports` is a comma-separated list of port numbers (e.g. "80,443").
+/// An empty string means no ports are associated.
+#[server]
+pub async fn create_application(name: String, ports: String) -> Result<Application, ServerFnError> {
+    use sqlx::AnyPool;
+    use crate::server::repository::applications as repo;
+
+    let pool = use_context::<AnyPool>()
+        .ok_or_else(|| ServerFnError::new("Database pool not found in context"))?;
+
+    let app = repo::create_application(&pool, &name)
+        .await
+        .map_err(|e| ServerFnError::new(e.to_string()))?;
+
+    let port_numbers: Vec<u16> = ports
+        .split(',')
+        .filter_map(|s| s.trim().parse::<u16>().ok())
+        .filter(|&p| p >= 1)
+        .collect();
+
+    for port_number in port_numbers {
+        repo::add_port_to_application(&pool, app.id, port_number)
+            .await
+            .map_err(|e| ServerFnError::new(e.to_string()))?;
+    }
+
+    Ok(app)
+}
+
 /// Deletes an application and all its port associations.
 ///
 /// Returns `true` if the application existed and was deleted.

src/app.rs

@@ -12,6 +12,7 @@ use leptos_router::{
 };
 
 use crate::client::{
+    application_detail::ApplicationDetailPage,
     applications::ApplicationsPage,
     home::HomePage,
     host_detail::HostDetailPage,
@@ -115,6 +116,7 @@ pub fn App() -> impl IntoView {
                     <Route path=path!("/hosts") view=HostsPage/>
                     <Route path=path!("/hosts/:id") view=HostDetailPage/>
                     <Route path=path!("/applications") view=ApplicationsPage/>
+                    <Route path=path!("/applications/:id") view=ApplicationDetailPage/>
                 </Routes>
             </main>
         </Router>

src/bin/seed.rs

@@ -85,5 +85,13 @@ async fn main() {
         .await
         .unwrap_or(0);
 
-    tracing::info!("Database now contains {} network(s) and {} host(s).", network_count, host_count);
+    let application_count: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM applications")
+        .fetch_one(&pool)
+        .await
+        .unwrap_or(0);
+
+    tracing::info!(
+        "Database now contains {} network(s), {} host(s) and {} application(s).",
+        network_count, host_count, application_count
+    );
 }

src/client/application_detail.rs

@@ -0,0 +1,311 @@
+// client/application_detail.rs — Application detail page
+//
+// Shows all information for a single application:
+//   - Identity form  : name — editable, saved with "Save changes"
+//   - Ports section  : ports associated with this application + Add/Remove per port
+//   - Hosts section  : hosts sharing at least one port with this application (read-only)
+//   - Delete button  : confirmation modal, then navigates back to /applications
+
+use leptos::prelude::*;
+use leptos_router::hooks::{use_navigate, use_params_map, use_query_map};
+
+use crate::api::applications::{
+    AddPortToApplication, DeleteApplication, RemovePortFromApplication,
+    UpdateApplication, get_application_detail,
+};
+
+// ─── Delete confirmation modal ────────────────────────────────────────────────
+
+#[component]
+fn DeleteModal(
+    app_name: String,
+    delete_action: ServerAction<DeleteApplication>,
+    app_id: i64,
+    show_modal: RwSignal<bool>,
+) -> impl IntoView {
+    view! {
+        <div class="modal-backdrop" on:click=move |_| show_modal.set(false)>
+            <div class="modal" on:click=move |e| e.stop_propagation()>
+                <div class="modal__header">
+                    <h2>"Delete application"</h2>
+                    <button class="modal__close" type="button" aria-label="Close"
+                        on:click=move |_| show_modal.set(false)>
+                        "×"
+                    </button>
+                </div>
+                <div class="modal__body">
+                    <p class="warning">
+                        "Are you sure you want to delete "
+                        <strong>{app_name}</strong>
+                        "? All port associations will also be removed."
+                    </p>
+                </div>
+                <div class="modal__actions">
+                    <button class="btn-secondary" type="button"
+                        on:click=move |_| show_modal.set(false)>
+                        "Cancel"
+                    </button>
+                    <button class="btn-danger" type="button"
+                        on:click=move |_| { delete_action.dispatch(DeleteApplication { id: app_id }); }>
+                        "Delete"
+                    </button>
+                </div>
+            </div>
+        </div>
+    }.into_any()
+}
+
+// ─── Main page component ──────────────────────────────────────────────────────
+
+#[component]
+pub fn ApplicationDetailPage() -> impl IntoView {
+    let params = use_params_map();
+    let app_id = move || {
+        params.read().get("id")
+            .and_then(|s| s.parse::<i64>().ok())
+            .unwrap_or(0)
+    };
+
+    let query = use_query_map();
+    let back_url = move || {
+        query.read().get("back")
+            .map(|s| s.to_string())
+            .unwrap_or_else(|| "/applications".to_string())
+    };
+    let back_label = move || {
+        if back_url().starts_with("/hosts/") { "← Host" } else { "← Applications" }
+    };
+
+    let update_action      = ServerAction::<UpdateApplication>::new();
+    let add_port_action    = ServerAction::<AddPortToApplication>::new();
+    let remove_port_action = ServerAction::<RemovePortFromApplication>::new();
+    let delete_action      = ServerAction::<DeleteApplication>::new();
+
+    let show_delete_modal = RwSignal::new(false);
+
+    let app = LocalResource::new(move || {
+        let _ = update_action.version().get();
+        let _ = add_port_action.version().get();
+        let _ = remove_port_action.version().get();
+        get_application_detail(app_id())
+    });
+
+    let name_sig = RwSignal::new(String::new());
+    let new_port = RwSignal::new(String::new());
+
+    // Sync the editable name whenever fresh data arrives.
+    Effect::new(move |_| {
+        if let Some(r) = app.get() {
+            if let Ok(ref detail) = *r {
+                name_sig.set(detail.name.clone());
+            }
+        }
+    });
+
+    let navigate = use_navigate();
+    Effect::new(move |_| {
+        if let Some(Ok(true)) = delete_action.value().get() {
+            navigate("/applications", Default::default());
+        }
+    });
+
+    view! {
+        <div class="application-detail-page">
+            // Delete modal lives OUTSIDE <Suspense> so it is not unmounted when
+            // the application resource re-fetches.
+            {move || show_delete_modal.get().then(|| view! {
+                <DeleteModal
+                    app_name=name_sig.get()
+                    delete_action=delete_action
+                    app_id=app_id()
+                    show_modal=show_delete_modal
+                />
+            })}
+
+            <Suspense fallback=|| view! { <p class="empty">"Loading application…"</p> }>
+                {move || app.get().map(|r| match (*r).clone() {
+                    Err(e) => view! {
+                        <p class="error">"Could not load application: " {e.to_string()}</p>
+                    }.into_any(),
+
+                    Ok(detail) => {
+                        let id         = detail.id;
+                        let port_count = detail.ports.len();
+                        let host_count = detail.hosts.len();
+                        let ports      = detail.ports;
+                        let hosts      = detail.hosts;
+
+                        let ports_list = if ports.is_empty() {
+                            view! {
+                                <p class="empty">"No ports associated with this application."</p>
+                            }.into_any()
+                        } else {
+                            view! {
+                                <div class="port-list">
+                                    {ports.into_iter().map(|num| {
+                                        view! {
+                                            <div class="port-row">
+                                                <span class="port-row__number">{num}</span>
+                                                <button
+                                                    class="btn-danger"
+                                                    type="button"
+                                                    on:click=move |_| {
+                                                        remove_port_action.dispatch(
+                                                            RemovePortFromApplication {
+                                                                application_id: id,
+                                                                port_number: num,
+                                                            }
+                                                        );
+                                                    }
+                                                >
+                                                    "Remove"
+                                                </button>
+                                            </div>
+                                        }
+                                    }).collect_view()}
+                                </div>
+                            }.into_any()
+                        };
+
+                        let hosts_list = if hosts.is_empty() {
+                            view! {
+                                <p class="empty">"No hosts share a port with this application."</p>
+                            }.into_any()
+                        } else {
+                            view! {
+                                <div class="app-list">
+                                    {hosts.into_iter().map(|host| {
+                                        view! {
+                                            <div class="app-row">
+                                                <a class="table-link"
+                                                    href=format!("/hosts/{}?back=/applications/{}", host.id, id)>
+                                                    {host.name}
+                                                </a>
+                                                <span class="cell-mono">{host.ip}</span>
+                                            </div>
+                                        }
+                                    }).collect_view()}
+                                </div>
+                            }.into_any()
+                        };
+
+                        view! {
+                            // ── Page header ───────────────────────────────────
+                            <div class="page-header detail-page-header">
+                                <a class="back-btn" href=move || back_url()>
+                                    {move || back_label()}
+                                </a>
+                                <h1 class="detail-page-title">{move || name_sig.get()}</h1>
+                            </div>
+
+                            // ── Identity form ─────────────────────────────────
+                            <section class="detail-section">
+                                <h2 class="detail-section__title">"Identity"</h2>
+                                <div class="detail-form">
+                                    <label class="detail-field">
+                                        "Name"
+                                        <input
+                                            type="text"
+                                            prop:value=move || name_sig.get()
+                                            on:input=move |e| name_sig.set(event_target_value(&e))
+                                        />
+                                    </label>
+
+                                    {move || update_action.value().get()
+                                        .and_then(|r| r.err())
+                                        .map(|e| view! { <p class="error">{e.to_string()}</p> })
+                                    }
+
+                                    <div class="form-actions">
+                                        <button
+                                            class="btn-primary"
+                                            type="button"
+                                            on:click=move |_| {
+                                                update_action.dispatch(UpdateApplication {
+                                                    id,
+                                                    name: name_sig.get_untracked(),
+                                                });
+                                            }
+                                        >
+                                            "Save changes"
+                                        </button>
+                                    </div>
+                                </div>
+                            </section>
+
+                            // ── Ports section ─────────────────────────────────
+                            <section class="detail-section">
+                                <h2 class="detail-section__title">
+                                    {format!("Associated ports ({})", port_count)}
+                                </h2>
+
+                                {ports_list}
+
+                                {move || remove_port_action.value().get()
+                                    .and_then(|r| r.err())
+                                    .map(|e| view! {
+                                        <p class="error">"Remove failed: " {e.to_string()}</p>
+                                    })
+                                }
+
+                                <div class="port-add-row">
+                                    <input
+                                        type="number"
+                                        min="1"
+                                        max="65535"
+                                        placeholder="Port number (1–65535)"
+                                        prop:value=move || new_port.get()
+                                        on:input=move |e| new_port.set(event_target_value(&e))
+                                    />
+                                    <button
+                                        class="btn-primary"
+                                        type="button"
+                                        on:click=move |_| {
+                                            let raw = new_port.get_untracked();
+                                            if let Ok(n) = raw.trim().parse::<i64>() {
+                                                if (1..=65535).contains(&n) {
+                                                    add_port_action.dispatch(AddPortToApplication {
+                                                        application_id: id,
+                                                        port_number: n as u16,
+                                                    });
+                                                    new_port.set(String::new());
+                                                }
+                                            }
+                                        }
+                                    >
+                                        "Add port"
+                                    </button>
+                                    {move || add_port_action.value().get()
+                                        .and_then(|r| r.err())
+                                        .map(|e| view! {
+                                            <p class="error">"Add failed: " {e.to_string()}</p>
+                                        })
+                                    }
+                                </div>
+                            </section>
+
+                            // ── Hosts section (read-only — linked via shared ports) ──
+                            <section class="detail-section">
+                                <h2 class="detail-section__title">
+                                    {format!("Linked hosts ({})", host_count)}
+                                </h2>
+                                {hosts_list}
+                            </section>
+
+                            // ── Danger zone ───────────────────────────────────
+                            <div class="danger-zone">
+                                <button
+                                    class="btn-danger-solid"
+                                    type="button"
+                                    on:click=move |_| show_delete_modal.set(true)
+                                >
+                                    "Delete application"
+                                </button>
+                            </div>
+                        }.into_any()
+                    }
+                })}
+            </Suspense>
+        </div>
+    }.into_any()
+}

src/client/applications.rs

@@ -8,6 +8,7 @@
 
 use leptos::prelude::*;
 use leptos::form::ActionForm;
+use leptos::html::Input;
 
 use crate::api::applications::{
     ApplicationWithCounts, CreateApplication, DeleteApplication,
@@ -21,19 +22,33 @@ fn AddApplicationModal(
     create_action: ServerAction<CreateApplication>,
     show_modal: RwSignal<bool>,
 ) -> impl IntoView {
-    Effect::new(move |_| {
-        if let Some(Ok(_)) = create_action.value().get() {
-            show_modal.set(false);
+    use leptos::task::spawn_local;
+
+    let name_ref = NodeRef::<Input>::new();
+
+    // Defer focus to the next microtask so the element is in the DOM.
+    // Using get_untracked() avoids subscribing to NodeRef's reactive signal,
+    // which would otherwise re-trigger during modal unmount and cause
+    // "closure invoked after being dropped" in wasm-bindgen.
+    spawn_local(async move {
+        if let Some(el) = name_ref.get_untracked() {
+            let _ = el.focus();
         }
     });
 
+    // close() defers show_modal.set(false) to the next microtask.
+    // Without this, setting the signal synchronously inside a click handler
+    // unmounts the modal (and frees its closures) while the handler is still
+    // on the call stack, causing wasm-bindgen to panic.
+    let close = move || spawn_local(async move { show_modal.set(false) });
+
     view! {
-        <div class="modal-backdrop" on:click=move |_| show_modal.set(false)>
+        <div class="modal-backdrop" on:click=move |_| close()>
             <div class="modal" on:click=move |e| e.stop_propagation()>
                 <div class="modal__header">
                     <h2>"Add an application"</h2>
                     <button class="modal__close" type="button" aria-label="Close"
-                        on:click=move |_| show_modal.set(false)>
+                        on:click=move |_| close()>
                         "×"
                     </button>
                 </div>
@@ -43,17 +58,27 @@ fn AddApplicationModal(
                         <label>
                             "Name"
                             <input
+                                node_ref=name_ref
                                 type="text"
                                 name="name"
                                 placeholder="e.g. Nginx, PostgreSQL, Prometheus"
                                 required
                             />
                         </label>
+                        <label>
+                            "Associated ports"
+                            <input
+                                type="text"
+                                name="ports"
+                                placeholder="e.g. 22, 80, 443"
+                            />
+                            <span class="field-hint">"Comma-separated port numbers"</span>
+                        </label>
                     </div>
 
                     <div class="modal__actions">
                         <button class="btn-secondary" type="button"
-                            on:click=move |_| show_modal.set(false)>
+                            on:click=move |_| close()>
                             "Cancel"
                         </button>
                         <button type="submit">"Add application"</button>
@@ -132,6 +157,19 @@ pub fn ApplicationsPage() -> impl IntoView {
     // Name filter (client-side — list is typically small)
     let name_filter = RwSignal::new(String::new());
 
+    // Close the add modal when the action transitions pending→done with Ok.
+    // Lives in the parent so it is never recreated across modal open/close cycles,
+    // which avoids the stale-value re-trigger bug.
+    Effect::new(move |was_pending: Option<bool>| {
+        let is_pending = create_action.pending().get();
+        if was_pending == Some(true) && !is_pending {
+            if let Some(Ok(_)) = create_action.value().get() {
+                show_modal.set(false);
+            }
+        }
+        is_pending
+    });
+
     // Close the delete modal automatically after a successful deletion.
     Effect::new(move |_| {
         if let Some(Ok(_)) = delete_action.value().get() {
@@ -225,10 +263,15 @@ pub fn ApplicationsPage() -> impl IntoView {
                                                     let app_clone = app.clone();
                                                     view! {
                                                         <tr>
-                                                            <td>{app.name}</td>
+                                                            <td>
+                                                                <a class="table-link"
+                                                                    href=format!("/applications/{}", app.id)>
+                                                                    {app.name}
+                                                                </a>
+                                                            </td>
                                                             <td class="col-count">{app.host_count}</td>
                                                             <td class="col-actions">
-                                                                <button on:click=move |_| {
+                                                                <button class="btn-danger" on:click=move |_| {
                                                                     pending_delete.set(Some(app_clone.clone()));
                                                                 }>
                                                                     "Delete"

src/client/host_detail.rs

@@ -232,7 +232,9 @@ pub fn HostDetailPage() -> impl IntoView {
             .unwrap_or_else(|| "/hosts".to_string())
     };
     let back_label = move || {
-        if back_url().starts_with("/networks/") { "← Network" } else { "← Hosts" }
+        if back_url().starts_with("/networks/")     { "← Network" }
+        else if back_url().starts_with("/applications/") { "← Application" }
+        else { "← Hosts" }
     };
 
     let update_action      = ServerAction::<UpdateHost>::new();
@@ -245,14 +247,16 @@ pub fn HostDetailPage() -> impl IntoView {
     let show_delete_modal  = RwSignal::new(false);
     let show_add_app_modal = RwSignal::new(false);
 
-    // Auto-close the add-app modal after a successful addition.
-    // Keeping this Effect in the parent avoids the re-trigger bug that would
-    // occur if the Effect were inside AddAppModal (it would fire on mount
-    // if the action already held a previous Ok value).
-    Effect::new(move |_| {
-        if let Some(Ok(_)) = add_app_action.value().get() {
-            show_add_app_modal.set(false);
+    // Auto-close the add-app modal when the action completes successfully.
+    // Lives here (not inside AddAppModal) so it is never recreated across modal open/close cycles.
+    Effect::new(move |was_pending: Option<bool>| {
+        let is_pending = add_app_action.pending().get();
+        if was_pending == Some(true) && !is_pending {
+            if let Some(Ok(_)) = add_app_action.value().get() {
+                show_add_app_modal.set(false);
+            }
         }
+        is_pending
     });
 
     // LocalResource avoids reading the resource outside <Suspense> during hydration,
@@ -305,6 +309,25 @@ pub fn HostDetailPage() -> impl IntoView {
 
     view! {
         <div class="host-detail-page">
+            // Modals live OUTSIDE <Suspense> so they are not unmounted when the
+            // host resource re-fetches (which would kill their reactive subscriptions).
+            {move || show_add_app_modal.get().then(|| view! {
+                <AddAppModal
+                    host_id=host_id()
+                    available_apps_res=available_apps_res
+                    add_action=add_app_action
+                    show_modal=show_add_app_modal
+                />
+            })}
+            {move || show_delete_modal.get().then(|| view! {
+                <DeleteModal
+                    host_name=name_sig.get()
+                    delete_action=delete_action
+                    host_id=host_id()
+                    show_modal=show_delete_modal
+                />
+            })}
+
             <Suspense fallback=|| view! { <p class="empty">"Loading host…"</p> }>
                 {move || host.get().map(|r| match (*r).clone() {
                     Err(e) => view! {
@@ -313,7 +336,6 @@ pub fn HostDetailPage() -> impl IntoView {
 
                     Ok(detail) => {
                         let id           = detail.id;
-                        let modal_name   = detail.name.clone();
                         let port_count   = detail.ports.len();
                         let app_count    = detail.applications.len();
                         let ports        = detail.ports;
@@ -365,7 +387,10 @@ pub fn HostDetailPage() -> impl IntoView {
                                         let app_id = app.id;
                                         view! {
                                             <div class="app-row">
-                                                <span class="app-row__name">{app.name}</span>
+                                                <a class="table-link app-row__name"
+                                                    href=format!("/applications/{}?back=/hosts/{}", app_id, id)>
+                                                    {app.name}
+                                                </a>
                                                 <button
                                                     class="btn-danger"
                                                     type="button"
@@ -429,7 +454,7 @@ pub fn HostDetailPage() -> impl IntoView {
                                                         view! {
                                                             <option
                                                                 value=n.id.to_string()
-                                                                selected=(n.id == current)
+                                                                selected=n.id == current
                                                             >
                                                                 {label}
                                                             </option>
@@ -541,16 +566,6 @@ pub fn HostDetailPage() -> impl IntoView {
                                 </div>
                             </section>
 
-                            // ── Add applications modal ────────────────────────
-                            {move || show_add_app_modal.get().then(|| view! {
-                                <AddAppModal
-                                    host_id=id
-                                    available_apps_res=available_apps_res
-                                    add_action=add_app_action
-                                    show_modal=show_add_app_modal
-                                />
-                            })}
-
                             // ── Danger zone ───────────────────────────────────
                             <div class="danger-zone">
                                 <button
@@ -561,16 +576,6 @@ pub fn HostDetailPage() -> impl IntoView {
                                     "Delete host"
                                 </button>
                             </div>
-
-                            // ── Delete modal (conditional) ────────────────────
-                            {move || show_delete_modal.get().then(|| view! {
-                                <DeleteModal
-                                    host_name=modal_name.clone()
-                                    delete_action=delete_action
-                                    host_id=id
-                                    show_modal=show_delete_modal
-                                />
-                            })}
                         }.into_any()
                     }
                 })}

src/client/hosts.rs

@@ -12,6 +12,7 @@
 
 use leptos::prelude::*;
 use leptos::form::ActionForm;
+use leptos::html::Input;
 
 use crate::api::{
     applications::get_applications,
@@ -76,15 +77,20 @@ fn AddHostModal(
     networks_res: LocalResource<Result<Vec<crate::models::Network>, ServerFnError>>,
     show_modal: RwSignal<bool>,
 ) -> impl IntoView {
-    // Close the modal automatically after a successful creation.
-    Effect::new(move |_| {
-        if let Some(Ok(_)) = create_action.value().get() {
-            show_modal.set(false);
+    use leptos::task::spawn_local;
+
+    let name_ref = NodeRef::<Input>::new();
+
+    spawn_local(async move {
+        if let Some(el) = name_ref.get_untracked() {
+            let _ = el.focus();
         }
     });
 
+    let close = move || spawn_local(async move { show_modal.set(false) });
+
     view! {
-        <div class="modal-backdrop" on:click=move |_| show_modal.set(false)>
+        <div class="modal-backdrop" on:click=move |_| close()>
             <div class="modal" on:click=move |e| e.stop_propagation()>
                 <div class="modal__header">
                     <h2>"Add a host"</h2>
@@ -92,7 +98,7 @@ fn AddHostModal(
                         class="modal__close"
                         type="button"
                         aria-label="Close"
-                        on:click=move |_| show_modal.set(false)
+                        on:click=move |_| close()
                     >"×"</button>
                 </div>
 
@@ -100,7 +106,7 @@ fn AddHostModal(
                     <div class="add-form__fields">
                         <label>
                             "Name"
-                            <input type="text" name="name" placeholder="e.g. web-server-01" required/>
+                            <input node_ref=name_ref type="text" name="name" placeholder="e.g. web-server-01" required/>
                         </label>
                         <label>
                             "IP address"
@@ -134,7 +140,7 @@ fn AddHostModal(
                         <button
                             class="btn-secondary"
                             type="button"
-                            on:click=move |_| show_modal.set(false)
+                            on:click=move |_| close()
                         >"Cancel"</button>
                         <button type="submit">"Add host"</button>
                     </div>
@@ -364,6 +370,17 @@ pub fn HostsPage() -> impl IntoView {
     // None = no modal, Some((id, name)) = delete confirmation open.
     let pending_delete: RwSignal<Option<(i64, String)>> = RwSignal::new(None);
 
+    // Close the add modal on pending→done with Ok (lives in parent to avoid stale-value re-trigger).
+    Effect::new(move |was_pending: Option<bool>| {
+        let is_pending = create_action.pending().get();
+        if was_pending == Some(true) && !is_pending {
+            if let Some(Ok(_)) = create_action.value().get() {
+                show_modal.set(false);
+            }
+        }
+        is_pending
+    });
+
     // Close the delete modal automatically after a successful deletion.
     Effect::new(move |_| {
         if let Some(Ok(_)) = delete_action.value().get() {

src/client/mod.rs

@@ -9,10 +9,11 @@
 // Do not place code here that requires browser-only APIs (window, document...)
 // without guarding it with `#[cfg(target_arch = "wasm32")]`.
 
-pub mod applications;   // Applications list and creation
-pub mod home;           // Home page
-pub mod host_detail;    // Host detail: identity, ports, edit, delete
-pub mod hosts;          // Hosts list with filters and pagination
-pub mod network_detail; // Network detail: info + paginated host list
-pub mod networks;       // Networks list and creation
-pub mod theme;          // Theme toggle component (light / dark / system)
+pub mod application_detail; // Application detail: identity, ports, linked hosts, delete
+pub mod applications;       // Applications list and creation
+pub mod home;               // Home page
+pub mod host_detail;        // Host detail: identity, ports, edit, delete
+pub mod hosts;              // Hosts list with filters and pagination
+pub mod network_detail;     // Network detail: info + paginated host list
+pub mod networks;           // Networks list and creation
+pub mod theme;              // Theme toggle component (light / dark / system)

src/server/repository/applications.rs

@@ -42,6 +42,18 @@ pub async fn create_application(pool: &AnyPool, name: &str) -> Result<Applicatio
     Ok(row_to_application(&row))
 }
 
+/// Updates the name of an application. Returns the updated record.
+pub async fn update_application(pool: &AnyPool, id: i64, name: &str) -> Result<Application, DbError> {
+    let row = sqlx::query(
+        "UPDATE applications SET name = $1 WHERE id = $2 RETURNING id, name",
+    )
+    .bind(name)
+    .bind(id)
+    .fetch_one(pool)
+    .await?;
+    Ok(row_to_application(&row))
+}
+
 /// Deletes an application and its port associations (via `ON DELETE CASCADE`).
 ///
 /// Returns `true` if a row was deleted, `false` if the id did not exist.