feat(centralui): Site Call KPI tiles on the Health dashboard

src/ScadaLink.CentralUI/Components/Health/SiteCallKpiTiles.razor

@@ -0,0 +1,60 @@
+@*
+    Site Call Audit (#22) Task 7 — three Health-dashboard KPI tiles for the
+    Site Call channel: Buffered / Parked / Stuck. Renders Bootstrap card tiles
+    in a single row, each acting as a navigation link to a pre-filtered Site
+    Calls report view. The component is purely presentational — the parent page
+    owns the refresh loop and passes the latest snapshot via the Snapshot
+    parameter. Mirrors AuditKpiTiles and the Notification Outbox KPI section.
+*@
+
+@namespace ScadaLink.CentralUI.Components.Health
+@inject NavigationManager Navigation
+
+<div class="d-flex justify-content-between align-items-center mb-2">
+    <h6 class="text-muted mb-0">Site Calls</h6>
+    <a class="small" href="/site-calls/report">View details &rarr;</a>
+</div>
+<div class="row g-3 mb-3">
+    @* ── Buffered tile ─────────────────────────────────────────────────────── *@
+    <div class="col-lg-4 col-md-6 col-12">
+        <button type="button"
+                class="card h-100 w-100 text-start border-0 shadow-none p-0 site-call-kpi-tile"
+                data-test="site-call-kpi-buffered"
+                @onclick="NavigateToBuffered">
+            <div class="card-body text-center">
+                <h3 class="mb-0">@BufferedDisplay</h3>
+                <small class="text-muted">Buffered</small>
+            </div>
+        </button>
+    </div>
+
+    @* ── Stuck tile ────────────────────────────────────────────────────────── *@
+    <div class="col-lg-4 col-md-6 col-12">
+        <button type="button"
+                class="card h-100 w-100 text-start border-0 shadow-none p-0 site-call-kpi-tile @StuckBorderClass"
+                data-test="site-call-kpi-stuck"
+                @onclick="NavigateToStuck">
+            <div class="card-body text-center">
+                <h3 class="mb-0 @StuckTextClass">@StuckDisplay</h3>
+                <small class="text-muted">Stuck</small>
+            </div>
+        </button>
+    </div>
+
+    @* ── Parked tile ───────────────────────────────────────────────────────── *@
+    <div class="col-lg-4 col-md-6 col-12">
+        <button type="button"
+                class="card h-100 w-100 text-start border-0 shadow-none p-0 site-call-kpi-tile @ParkedBorderClass"
+                data-test="site-call-kpi-parked"
+                @onclick="NavigateToParked">
+            <div class="card-body text-center">
+                <h3 class="mb-0 @ParkedTextClass">@ParkedDisplay</h3>
+                <small class="text-muted">Parked</small>
+            </div>
+        </button>
+    </div>
+</div>
+@if (!IsAvailable && !string.IsNullOrEmpty(ErrorMessage))
+{
+    <div class="text-muted small mb-3">Site Call KPIs unavailable: @ErrorMessage</div>
+}

src/ScadaLink.CentralUI/Components/Health/SiteCallKpiTiles.razor.cs

@@ -0,0 +1,130 @@
+using Microsoft.AspNetCore.Components;
+using ScadaLink.Commons.Messages.Audit;
+
+namespace ScadaLink.CentralUI.Components.Health;
+
+/// <summary>
+/// Site Call Audit (#22) Task 7 code-behind for <see cref="SiteCallKpiTiles"/>.
+/// Renders three KPI tiles — Buffered, Stuck, Parked — from a
+/// <see cref="SiteCallKpiResponse"/> the parent Health dashboard supplies.
+/// Tiles act as drill-in links: clicking navigates to <c>/site-calls/report</c>
+/// with the relevant query-string filter pre-applied. Mirrors
+/// <see cref="AuditKpiTiles"/> and the Notification Outbox KPI section on the
+/// Health dashboard.
+/// </summary>
+/// <remarks>
+/// <para>
+/// <b>Why purely presentational.</b> The Health dashboard already owns a 10s
+/// auto-refresh loop; pushing that into the tile component would either
+/// duplicate it (one timer per tile) or awkwardly couple back to the page. The
+/// parent passes a fresh <see cref="SiteCallKpiResponse"/> every refresh and the
+/// tile component re-renders. This is the same contract <see cref="AuditKpiTiles"/>
+/// follows.
+/// </para>
+/// <para>
+/// <b>Snapshot shape.</b> Unlike <see cref="AuditKpiTiles"/> — which takes a
+/// dedicated <c>AuditLogKpiSnapshot</c> type — Site Call KPIs travel in the
+/// <see cref="SiteCallKpiResponse"/> message itself (it carries the KPI fields
+/// directly), so that record doubles as the snapshot here. <see cref="IsAvailable"/>
+/// is a separate flag rather than the record's own <c>Success</c> so the parent
+/// can also surface a transport failure (an Ask that threw) as unavailable.
+/// </para>
+/// <para>
+/// <b>Threshold borders.</b> Mirrors the Notification Outbox tile pattern: the
+/// Parked tile gets a danger border when <c>ParkedCount &gt; 0</c>; the Stuck
+/// tile gets a warning border when <c>StuckCount &gt; 0</c>. Buffered is a plain
+/// count tile with no threshold colour — a non-zero buffer is normal operation.
+/// </para>
+/// </remarks>
+public partial class SiteCallKpiTiles
+{
+    /// <summary>
+    /// Latest KPI snapshot. <c>null</c> means the parent has not loaded it yet
+    /// or the load failed — the tiles render em dashes in that case.
+    /// </summary>
+    [Parameter] public SiteCallKpiResponse? Snapshot { get; set; }
+
+    /// <summary>
+    /// True when <see cref="Snapshot"/> is a successful query result. False when
+    /// the parent's refresh threw, or the response itself reported a fault, and
+    /// the displayed values should be rendered as em dashes with an error
+    /// explanation underneath.
+    /// </summary>
+    [Parameter] public bool IsAvailable { get; set; }
+
+    /// <summary>
+    /// Optional error message to render underneath the tiles when
+    /// <see cref="IsAvailable"/> is false. Mirrors how the Notification Outbox
+    /// section on the Health dashboard surfaces transient KPI failures.
+    /// </summary>
+    [Parameter] public string? ErrorMessage { get; set; }
+
+    // ── Buffered tile ───────────────────────────────────────────────────────
+
+    private string BufferedDisplay =>
+        IsAvailable && Snapshot is not null
+            ? Snapshot.BufferedCount.ToString("N0")
+            : "—";
+
+    private void NavigateToBuffered()
+    {
+        // Buffered is "everything still in flight" — no single status maps to
+        // it, so the natural drill-in is the unfiltered Site Calls report sorted
+        // by newest, mirroring how the Audit volume/backlog tiles drop the
+        // operator on the unfiltered Audit Log grid.
+        Navigation.NavigateTo("/site-calls/report");
+    }
+
+    // ── Stuck tile ──────────────────────────────────────────────────────────
+
+    private string StuckDisplay =>
+        IsAvailable && Snapshot is not null
+            ? Snapshot.StuckCount.ToString("N0")
+            : "—";
+
+    // Stuck above zero is a warning signal — cached calls that have been
+    // Pending/Retrying past the stuck-age threshold. Matches the Notification
+    // Outbox Stuck tile (border-warning when StuckCount > 0).
+    private string StuckBorderClass =>
+        IsAvailable && Snapshot is not null && Snapshot.StuckCount > 0
+            ? "border-warning"
+            : string.Empty;
+
+    private string StuckTextClass =>
+        IsAvailable && Snapshot is not null && Snapshot.StuckCount > 0
+            ? "text-warning"
+            : string.Empty;
+
+    private void NavigateToStuck()
+    {
+        // Drill in with the report's "stuck only" filter pre-applied.
+        Navigation.NavigateTo("/site-calls/report?stuck=true");
+    }
+
+    // ── Parked tile ─────────────────────────────────────────────────────────
+
+    private string ParkedDisplay =>
+        IsAvailable && Snapshot is not null
+            ? Snapshot.ParkedCount.ToString("N0")
+            : "—";
+
+    // Parked above zero is a danger signal — cached calls that exhausted retries
+    // and need an operator Retry/Discard. Matches the Notification Outbox Parked
+    // tile (border-danger when ParkedCount > 0).
+    private string ParkedBorderClass =>
+        IsAvailable && Snapshot is not null && Snapshot.ParkedCount > 0
+            ? "border-danger"
+            : string.Empty;
+
+    private string ParkedTextClass =>
+        IsAvailable && Snapshot is not null && Snapshot.ParkedCount > 0
+            ? "text-danger"
+            : string.Empty;
+
+    private void NavigateToParked()
+    {
+        // Drill in pre-filtered to Parked — the report's Status filter accepts
+        // ?status=Parked and Parked rows carry the Retry/Discard relay actions.
+        Navigation.NavigateTo("/site-calls/report?status=Parked");
+    }
+}

src/ScadaLink.CentralUI/Components/Pages/Monitoring/Health.razor

@@ -8,6 +8,7 @@
 @using ScadaLink.Commons.Interfaces.Repositories
 @using ScadaLink.HealthMonitoring
 @using ScadaLink.Commons.Messages.Notification
+@using ScadaLink.Commons.Messages.Audit
 @using ScadaLink.Communication
 @implements IDisposable
 @inject ICentralHealthAggregator HealthAggregator
@@ -60,6 +61,12 @@
         <div class="text-muted small mb-3">Notification Outbox KPIs unavailable: @_outboxKpiError</div>
     }
 
+    @* Site Call Audit (#22) Task 7 — three KPI tiles for the Site Call channel
+       (buffered / stuck / parked). Refreshed alongside the site states. *@
+    <SiteCallKpiTiles Snapshot="@_siteCallKpi"
+                      IsAvailable="@_siteCallKpiAvailable"
+                      ErrorMessage="@_siteCallKpiError" />
+
     @* Audit Log (#23) M7 Bundle E — three KPI tiles for the Audit channel
        (volume / error rate / backlog). Refreshed alongside the site states. *@
     <AuditKpiTiles Snapshot="@_auditKpi"
@@ -364,6 +371,13 @@
     private bool _auditKpiAvailable;
     private string? _auditKpiError;
 
+    // Site Call Audit (#22) Task 7 — Site Call KPI tiles. Point-in-time counts
+    // from the central SiteCalls table, fetched alongside the site states. The
+    // SiteCallKpiResponse message doubles as the snapshot the tile takes.
+    private SiteCallKpiResponse? _siteCallKpi;
+    private bool _siteCallKpiAvailable;
+    private string? _siteCallKpiError;
+
     private static bool SiteHasActiveErrors(SiteHealthState state)
     {
         var report = state.LatestReport;
@@ -401,6 +415,7 @@
     {
         _siteStates = HealthAggregator.GetAllSiteStates();
         await LoadOutboxKpis();
+        await LoadSiteCallKpis();
         await LoadAuditKpis();
     }
 
@@ -429,6 +444,36 @@
         }
     }
 
+    // Site Call KPI loader: wraps the service call so a transient fault degrades
+    // the three Site Call tiles to em dashes with an inline error rather than
+    // killing the dashboard. Mirrors LoadOutboxKpis's error handling shape — a
+    // response with Success == false (repository fault) and an Ask that threw
+    // (transport fault) both collapse to "unavailable".
+    private async Task LoadSiteCallKpis()
+    {
+        try
+        {
+            var response = await CommunicationService.GetSiteCallKpisAsync(
+                new SiteCallKpiRequest(Guid.NewGuid().ToString("N")));
+            if (response.Success)
+            {
+                _siteCallKpi = response;
+                _siteCallKpiAvailable = true;
+                _siteCallKpiError = null;
+            }
+            else
+            {
+                _siteCallKpiAvailable = false;
+                _siteCallKpiError = response.ErrorMessage ?? "KPI query failed.";
+            }
+        }
+        catch (Exception ex)
+        {
+            _siteCallKpiAvailable = false;
+            _siteCallKpiError = $"KPI query failed: {ex.Message}";
+        }
+    }
+
     // Tiles show the numeric KPI when available, or an em dash when the outbox
     // KPI query failed — matching how the page renders other unavailable data.
     private string OutboxTileValue(int value) =>