ScadaBridge/src/ZB.MOM.WW.ScadaBridge.CentralUI/Components/Pages/Monitoring/AlarmSummary.razor

@page "/monitoring/alarms"
@attribute [Authorize(Policy = ZB.MOM.WW.ScadaBridge.Security.AuthorizationPolicies.RequireDeployment)]
@using ZB.MOM.WW.ScadaBridge.CentralUI.Components.Shared
@using ZB.MOM.WW.ScadaBridge.CentralUI.Services
@using ZB.MOM.WW.ScadaBridge.Commons.Entities.Sites
@using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Repositories
@using ZB.MOM.WW.ScadaBridge.Commons.Types.Enums
@implements IDisposable
@inject IAlarmSummaryService AlarmSummaryService
@inject ISiteRepository SiteRepository

<div class="container-fluid mt-3" data-test="alarm-summary">
    <div class="d-flex justify-content-between align-items-center mb-3">
        <h4 class="mb-0">Alarm Summary</h4>
        <div class="d-flex align-items-center">
            @if (_selectedSiteId != null)
            {
                <span class="text-muted small me-2">Auto-refresh: @(_autoRefreshSeconds)s</span>
            }
            <button class="btn btn-outline-secondary btn-sm" @onclick="RefreshAsync"
                    disabled="@(_selectedSiteId == null || _loading)" data-test="alarm-summary-refresh">
                @(_loading ? "Refreshing…" : "Refresh")
            </button>
        </div>
    </div>

    @* ── Site picker ── *@
    <div class="card mb-3">
        <div class="card-body py-2">
            <div class="row g-2 align-items-end">
                <div class="col-auto">
                    <label class="form-label small mb-1" for="as-site">Site</label>
                    <select id="as-site" class="form-select form-select-sm" style="min-width: 200px;"
                            value="@(_selectedSiteId?.ToString() ?? "")" @onchange="OnSiteChangedAsync"
                            data-test="alarm-summary-site">
                        <option value="">Select site…</option>
                        @foreach (var site in _sites)
                        {
                            <option value="@site.Id">@site.Name</option>
                        }
                    </select>
                </div>
            </div>
        </div>
    </div>

    @if (_selectedSiteId == null)
    {
        <div class="alert alert-info" data-test="alarm-summary-empty">Select a site to view its current alarms.</div>
    }
    else
    {
        @* ── Roll-up tiles ── *@
        <div class="row g-3 mb-3">
            <div class="col-lg-3 col-md-6 col-12">
                <div class="card h-100 @(_rollup.TotalActive > 0 ? "border-danger" : "")">
                    <div class="card-body text-center">
                        <h3 class="mb-0 @(_rollup.TotalActive > 0 ? "text-danger" : "")" data-test="rollup-active">@_rollup.TotalActive</h3>
                        <small class="text-muted">Active Alarms</small>
                    </div>
                </div>
            </div>
            <div class="col-lg-3 col-md-6 col-12">
                <div class="card h-100">
                    <div class="card-body text-center">
                        <h3 class="mb-0" data-test="rollup-severity">@_rollup.WorstSeverity</h3>
                        <small class="text-muted">Worst Severity</small>
                    </div>
                </div>
            </div>
            <div class="col-lg-3 col-md-6 col-12">
                <div class="card h-100 @(_rollup.UnackedCount > 0 ? "border-warning" : "")">
                    <div class="card-body text-center">
                        <h3 class="mb-0 @(_rollup.UnackedCount > 0 ? "text-warning" : "")" data-test="rollup-unacked">@_rollup.UnackedCount</h3>
                        <small class="text-muted">Unacknowledged</small>
                    </div>
                </div>
            </div>
            <div class="col-lg-3 col-md-6 col-12">
                <div class="card h-100">
                    <div class="card-body text-center">
                        <h3 class="mb-0" data-test="rollup-total">@_rows.Count</h3>
                        <small class="text-muted">
                            Total Rows
                            @if (_rollup.CountsByKind.Count > 0)
                            {
                                <span> ·
                                    @string.Join(" / ", _rollup.CountsByKind
                                        .OrderBy(kv => kv.Key)
                                        .Select(kv => $"{KindLabel(kv.Key)} {kv.Value}"))
                                </span>
                            }
                        </small>
                    </div>
                </div>
            </div>
        </div>

        @if (_notReporting.Count > 0)
        {
            <div class="text-muted small mb-2" data-test="alarm-summary-not-reporting">
                Not reporting (@_notReporting.Count): @string.Join(", ", _notReporting)
            </div>
        }

        @* ── Filters ── *@
        <div class="card mb-3">
            <div class="card-body py-2">
                <div class="row g-2 align-items-end">
                    <div class="col-auto">
                        <label class="form-label small mb-1" for="as-f-instance">Instance</label>
                        <select id="as-f-instance" class="form-select form-select-sm" style="min-width: 160px;" @bind="_filterInstance" @bind:after="RecomputeVisibleRows">
                            <option value="">All</option>
                            @foreach (var name in DistinctInstances)
                            {
                                <option value="@name">@name</option>
                            }
                        </select>
                    </div>
                    <div class="col-auto">
                        <label class="form-label small mb-1" for="as-f-kind">Kind</label>
                        <select id="as-f-kind" class="form-select form-select-sm" @bind="_filterKind" @bind:after="RecomputeVisibleRows">
                            <option value="">All</option>
                            <option value="@AlarmKind.Computed">Computed</option>
                            <option value="@AlarmKind.NativeOpcUa">OPC UA</option>
                            <option value="@AlarmKind.NativeMxAccess">MxAccess</option>
                        </select>
                    </div>
                    <div class="col-auto">
                        <label class="form-label small mb-1" for="as-f-state">State</label>
                        <select id="as-f-state" class="form-select form-select-sm" @bind="_filterState" @bind:after="RecomputeVisibleRows">
                            <option value="">All</option>
                            <option value="@AlarmState.Active">Active</option>
                            <option value="@AlarmState.Normal">Normal</option>
                        </select>
                    </div>
                    <div class="col-auto">
                        <label class="form-label small mb-1" for="as-f-ack">Ack</label>
                        <select id="as-f-ack" class="form-select form-select-sm" @bind="_filterAck" @bind:after="RecomputeVisibleRows">
                            <option value="">Any</option>
                            <option value="unacked">Unacked</option>
                            <option value="acked">Acked</option>
                        </select>
                    </div>
                    <div class="col-auto">
                        <label class="form-label small mb-1" for="as-f-sev">Min severity</label>
                        <input id="as-f-sev" type="number" min="0" max="1000" step="50"
                               class="form-control form-control-sm" style="width: 110px;"
                               @bind="_filterMinSeverity" @bind:after="RecomputeVisibleRows" />
                    </div>
                    <div class="col-auto flex-grow-1">
                        <label class="form-label small mb-1" for="as-f-name">Name search</label>
                        <input id="as-f-name" type="text" class="form-control form-control-sm"
                               placeholder="alarm name contains…" @bind="_filterName" @bind:event="oninput" @bind:after="RecomputeVisibleRows" />
                    </div>
                    <div class="col-auto">
                        <button class="btn btn-outline-secondary btn-sm" @onclick="ClearFilters">Clear</button>
                    </div>
                </div>
            </div>
        </div>

        @* ── Alarm table ── *@
        @if (_rows.Count == 0)
        {
            <div class="alert alert-success" data-test="alarm-summary-no-alarms">No alarms reported across this site's enabled instances.</div>
        }
        else
        {
            <div class="text-muted small mb-2">Showing @_visibleRows.Count of @_rows.Count</div>
            <div class="table-responsive">
                <table class="table table-sm table-hover align-middle">
                    @* UA6 (arch-review): sortable headers are keyboard-operable — tabindex="0",
                       aria-sort reflects the active sort direction, and Enter/Space toggle the
                       sort (Space preventDefault suppresses page scroll). The same pattern should
                       be applied to the other custom grids in the app; that fleet-wide sweep is
                       deferred and logged (arch-review UA6). *@
                    <thead>
                        <tr>
                            <th role="button" tabindex="0" aria-sort="@AriaSortFor("instance")"
                                @onclick='() => SortBy("instance")'
                                @onkeydown='e => OnHeaderKeyDown(e, "instance")' @onkeydown:preventDefault="_preventHeaderDefault">Instance @SortGlyph("instance")</th>
                            <th role="button" tabindex="0" aria-sort="@AriaSortFor("name")"
                                @onclick='() => SortBy("name")'
                                @onkeydown='e => OnHeaderKeyDown(e, "name")' @onkeydown:preventDefault="_preventHeaderDefault">Alarm @SortGlyph("name")</th>
                            <th>State / Kind</th>
                            <th role="button" tabindex="0" class="text-end" aria-sort="@AriaSortFor("severity")"
                                @onclick='() => SortBy("severity")'
                                @onkeydown='e => OnHeaderKeyDown(e, "severity")' @onkeydown:preventDefault="_preventHeaderDefault">Severity @SortGlyph("severity")</th>
                        </tr>
                    </thead>
                    <tbody>
                        @foreach (var row in _visibleRows)
                        {
                            <tr data-test="alarm-summary-row">
                                <td class="font-monospace small">@row.InstanceUniqueName</td>
                                <td>@row.Alarm.AlarmName</td>
                                <td><AlarmStateBadges Alarm="row.Alarm" /></td>
                                <td class="text-end font-monospace">@row.Alarm.Condition.Severity</td>
                            </tr>
                        }
                    </tbody>
                </table>
            </div>
        }
    }
</div>

@code {
    private IReadOnlyList<Site> _sites = Array.Empty<Site>();
    private int? _selectedSiteId;

    private IReadOnlyList<AlarmSummaryRow> _rows = Array.Empty<AlarmSummaryRow>();

    // P4 (arch-review): the filtered+sorted view is memoized rather than recomputed
    // on every render. RecomputeVisibleRows() refreshes it whenever the inputs change
    // (a fresh snapshot in RefreshAsync, a filter change via @bind:after, or a sort).
    private IReadOnlyList<AlarmSummaryRow> _visibleRows = Array.Empty<AlarmSummaryRow>();

    private IReadOnlyList<string> _notReporting = Array.Empty<string>();
    private AlarmRollup _rollup = new(0, 0, 0, new Dictionary<AlarmKind, int>());
    private bool _loading;

    private Timer? _refreshTimer;
    private readonly ZB.MOM.WW.ScadaBridge.CentralUI.Services.PollGate _pollGate = new();
    private const int _autoRefreshSeconds = 15;

    // ── Client-side filters ──
    private string _filterInstance = "";
    private string _filterKind = "";
    private string _filterState = "";
    private string _filterAck = "";
    private int? _filterMinSeverity;
    private string _filterName = "";

    // ── Sort ──
    private string _sortKey = "severity";
    private bool _sortDescending = true;

    protected override async Task OnInitializedAsync()
    {
        try
        {
            _sites = await SiteRepository.GetAllSitesAsync();
        }
        catch
        {
            // Non-fatal — the picker simply shows no sites.
        }
    }

    private async Task OnSiteChangedAsync(ChangeEventArgs e)
    {
        var raw = e.Value?.ToString();
        if (string.IsNullOrEmpty(raw) || !int.TryParse(raw, out var siteId))
        {
            _selectedSiteId = null;
            _rows = Array.Empty<AlarmSummaryRow>();
            _notReporting = Array.Empty<string>();
            _rollup = new AlarmRollup(0, 0, 0, new Dictionary<AlarmKind, int>());
            StopTimer();
            return;
        }

        _selectedSiteId = siteId;
        ClearFilters();
        await RefreshAsync();
        StartTimer();
    }

    private async Task RefreshAsync()
    {
        if (_selectedSiteId is not int siteId)
        {
            return;
        }

        _loading = true;
        try
        {
            var result = await AlarmSummaryService.GetSiteAlarmsAsync(siteId);
            _rows = result.Alarms;
            _notReporting = result.NotReportingInstances;
            _rollup = AlarmSummaryService.ComputeRollup(_rows);
            RecomputeVisibleRows();
        }
        catch
        {
            // Best-effort: a transient fault leaves the prior snapshot on screen
            // rather than blanking the page; the next poll / manual refresh retries.
        }
        finally
        {
            _loading = false;
        }
    }

    private void StartTimer()
    {
        StopTimer();
        _refreshTimer = new Timer(_ =>
        {
            if (!_pollGate.TryEnter()) return;
            InvokeAsync(async () =>
            {
                try
                {
                    await RefreshAsync();
                    StateHasChanged();
                }
                finally
                {
                    _pollGate.Exit();
                }
            });
        }, null, TimeSpan.FromSeconds(_autoRefreshSeconds), TimeSpan.FromSeconds(_autoRefreshSeconds));
    }

    private void StopTimer()
    {
        _refreshTimer?.Dispose();
        _refreshTimer = null;
    }

    private IEnumerable<string> DistinctInstances =>
        _rows.Select(r => r.InstanceUniqueName).Distinct().OrderBy(n => n, StringComparer.OrdinalIgnoreCase);

    // P4: recompute the memoized filtered+sorted view from the current snapshot and
    // filter/sort inputs. Called from RefreshAsync, each filter's @bind:after, and SortBy —
    // NOT per render.
    private void RecomputeVisibleRows() => _visibleRows = FilteredRows().ToList();

    private IEnumerable<AlarmSummaryRow> FilteredRows()
    {
        IEnumerable<AlarmSummaryRow> q = _rows;

        if (!string.IsNullOrEmpty(_filterInstance))
        {
            q = q.Where(r => r.InstanceUniqueName == _filterInstance);
        }
        if (Enum.TryParse<AlarmKind>(_filterKind, out var kind))
        {
            q = q.Where(r => r.Alarm.Kind == kind);
        }
        if (Enum.TryParse<AlarmState>(_filterState, out var state))
        {
            q = q.Where(r => r.Alarm.State == state);
        }
        if (_filterAck == "unacked")
        {
            q = q.Where(r => r.Alarm.Condition.Active && !r.Alarm.Condition.Acknowledged && r.Alarm.Kind != AlarmKind.Computed);
        }
        else if (_filterAck == "acked")
        {
            q = q.Where(r => r.Alarm.Condition.Acknowledged);
        }
        if (_filterMinSeverity is int min)
        {
            q = q.Where(r => r.Alarm.Condition.Severity >= min);
        }
        if (!string.IsNullOrWhiteSpace(_filterName))
        {
            q = q.Where(r => r.Alarm.AlarmName.Contains(_filterName, StringComparison.OrdinalIgnoreCase));
        }

        return SortRows(q);
    }

    private IEnumerable<AlarmSummaryRow> SortRows(IEnumerable<AlarmSummaryRow> rows)
    {
        Func<AlarmSummaryRow, object> key = _sortKey switch
        {
            "instance" => r => r.InstanceUniqueName,
            "name" => r => r.Alarm.AlarmName,
            _ => r => r.Alarm.Condition.Severity,
        };
        return _sortDescending ? rows.OrderByDescending(key) : rows.OrderBy(key);
    }

    private void SortBy(string key)
    {
        if (_sortKey == key)
        {
            _sortDescending = !_sortDescending;
        }
        else
        {
            _sortKey = key;
            _sortDescending = key == "severity";
        }
        RecomputeVisibleRows();
    }

    private string SortGlyph(string key) =>
        _sortKey != key ? "" : (_sortDescending ? "▼" : "▲");

    // UA6: aria-sort token for a sortable header — ascending/descending on the active
    // column, "none" otherwise (per the WAI-ARIA aria-sort value set).
    private string AriaSortFor(string key) =>
        _sortKey != key ? "none" : (_sortDescending ? "descending" : "ascending");

    // UA6: whether the last header keydown should suppress the browser default. Bound to
    // @onkeydown:preventDefault (evaluated at render), so it takes effect on the next
    // Space keydown to stop the page scrolling when a header has keyboard focus.
    private bool _preventHeaderDefault;

    // UA6: keyboard activation for the sortable headers — Enter or Space toggles the sort,
    // mirroring the pointer click.
    private void OnHeaderKeyDown(KeyboardEventArgs e, string key)
    {
        var isSpace = e.Key is " " or "Spacebar";
        _preventHeaderDefault = isSpace; // suppress Space page-scroll; leave Tab/others alone
        if (e.Key == "Enter" || isSpace)
        {
            SortBy(key);
        }
    }

    private void ClearFilters()
    {
        _filterInstance = "";
        _filterKind = "";
        _filterState = "";
        _filterAck = "";
        _filterMinSeverity = null;
        _filterName = "";
        RecomputeVisibleRows();
    }

    private static string KindLabel(AlarmKind kind) => kind switch
    {
        AlarmKind.NativeOpcUa => "OPC UA",
        AlarmKind.NativeMxAccess => "MxAccess",
        _ => "Computed"
    };

    public void Dispose() => StopTimer();
}