@page "/notifications/kpis"
@attribute [Authorize(Policy = ZB.MOM.WW.ScadaBridge.Security.AuthorizationPolicies.RequireDeployment)]
@using ZB.MOM.WW.ScadaBridge.Commons.Entities.Sites
@using ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Repositories
@using ZB.MOM.WW.ScadaBridge.Commons.Messages.Notification
@using ZB.MOM.WW.ScadaBridge.Commons.Types.Notifications
@using ZB.MOM.WW.ScadaBridge.Commons.Types.Kpi
@using ZB.MOM.WW.ScadaBridge.Communication
@using ZB.MOM.WW.ScadaBridge.CentralUI.Services
@inject CommunicationService CommunicationService
@inject ISiteRepository SiteRepository
@inject IKpiHistoryQueryService KpiHistory
@inject ILogger<NotificationKpis> Logger

<div class="container-fluid mt-3">
    <div class="d-flex justify-content-between align-items-center mb-3">
        <h4 class="mb-0">Notification KPIs</h4>
        <button class="btn btn-outline-secondary btn-sm" @onclick="RefreshAll" disabled="@_loading">
            @if (_loading) { <span class="spinner-border spinner-border-sm me-1" role="status"></span> }
            Refresh
        </button>
    </div>

    @* ── Global KPI tiles ── *@
    @if (_kpiError != null)
    {
        <div class="alert alert-warning py-2">KPIs unavailable: @_kpiError</div>
    }
    else
    {
        <div class="row g-3 mb-4">
            <div class="col-lg col-md-4 col-6">
                <div class="card h-100">
                    <div class="card-body text-center py-3">
                        <h3 class="mb-0">@_kpi.QueueDepth</h3>
                        <small class="text-muted">Queue Depth</small>
                    </div>
                </div>
            </div>
            <div class="col-lg col-md-4 col-6">
                <div class="card h-100 @(_kpi.StuckCount > 0 ? "border-warning" : "")">
                    <div class="card-body text-center py-3">
                        <h3 class="mb-0 @(_kpi.StuckCount > 0 ? "text-warning" : "")">@_kpi.StuckCount</h3>
                        <small class="text-muted">Stuck</small>
                    </div>
                </div>
            </div>
            <div class="col-lg col-md-4 col-6">
                <div class="card h-100 @(_kpi.ParkedCount > 0 ? "border-danger" : "")">
                    <div class="card-body text-center py-3">
                        <h3 class="mb-0 @(_kpi.ParkedCount > 0 ? "text-danger" : "")">@_kpi.ParkedCount</h3>
                        <small class="text-muted">Parked</small>
                    </div>
                </div>
            </div>
            <div class="col-lg col-md-4 col-6">
                <div class="card h-100">
                    <div class="card-body text-center py-3">
                        <h3 class="mb-0 text-success">@_kpi.DeliveredLastInterval</h3>
                        <small class="text-muted">Delivered (last interval)</small>
                    </div>
                </div>
            </div>
            <div class="col-lg col-md-4 col-6">
                <div class="card h-100">
                    <div class="card-body text-center py-3">
                        <h3 class="mb-0">@FormatAge(_kpi.OldestPendingAge)</h3>
                        <small class="text-muted">Oldest Pending Age</small>
                    </div>
                </div>
            </div>
        </div>
    }

    @* ── Per-node breakdown (additive) ── *@
    <h5 class="mb-2">Per-node breakdown</h5>
    @if (_perNodeError != null)
    {
        <div class="alert alert-warning py-2">Per-node KPIs unavailable: @_perNodeError</div>
    }
    else if (_perNode.Count == 0)
    {
        <div class="card mb-3">
            <div class="card-body text-center text-muted py-3">
                <div class="small">No per-node activity (rows may have a null SourceNode).</div>
            </div>
        </div>
    }
    else
    {
        <div class="table-responsive mb-3">
            <table class="table table-sm table-hover align-middle">
                <thead class="table-light">
                    <tr>
                        <th>Node</th>
                        <th class="text-end">Queue Depth</th>
                        <th class="text-end">Stuck</th>
                        <th class="text-end">Parked</th>
                        <th class="text-end">Delivered (last interval)</th>
                        <th class="text-end">Oldest Pending Age</th>
                    </tr>
                </thead>
                <tbody>
                    @foreach (var n in _perNode)
                    {
                        <tr @key="n.SourceNode" class="@(n.StuckCount > 0 ? "table-warning" : "")">
                            <td><code>@n.SourceNode</code></td>
                            <td class="text-end font-monospace">@n.QueueDepth</td>
                            <td class="text-end font-monospace @(n.StuckCount > 0 ? "text-warning" : "")">@n.StuckCount</td>
                            <td class="text-end font-monospace @(n.ParkedCount > 0 ? "text-danger" : "")">@n.ParkedCount</td>
                            <td class="text-end font-monospace text-success">@n.DeliveredLastInterval</td>
                            <td class="text-end font-monospace">@FormatAge(n.OldestPendingAge)</td>
                        </tr>
                    }
                </tbody>
            </table>
        </div>
    }

    @* ── Per-site breakdown ── *@
    <h5 class="mb-2">Per-site breakdown</h5>
    @if (_perSiteError != null)
    {
        <div class="alert alert-warning py-2">Per-site KPIs unavailable: @_perSiteError</div>
    }
    else if (_perSite.Count == 0)
    {
        <div class="card">
            <div class="card-body text-center text-muted py-4">
                <div class="small">No per-site activity.</div>
            </div>
        </div>
    }
    else
    {
        <div class="table-responsive">
            <table class="table table-sm table-hover align-middle">
                <thead class="table-light">
                    <tr>
                        <th>Site</th>
                        <th class="text-end">Queue Depth</th>
                        <th class="text-end">Stuck</th>
                        <th class="text-end">Parked</th>
                        <th class="text-end">Delivered (last interval)</th>
                        <th class="text-end">Oldest Pending Age</th>
                    </tr>
                </thead>
                <tbody>
                    @foreach (var s in _perSite)
                    {
                        <tr @key="s.SourceSiteId" class="@(s.StuckCount > 0 ? "table-warning" : "")">
                            <td>@SiteName(s.SourceSiteId)</td>
                            <td class="text-end font-monospace">@s.QueueDepth</td>
                            <td class="text-end font-monospace @(s.StuckCount > 0 ? "text-warning" : "")">@s.StuckCount</td>
                            <td class="text-end font-monospace @(s.ParkedCount > 0 ? "text-danger" : "")">@s.ParkedCount</td>
                            <td class="text-end font-monospace text-success">@s.DeliveredLastInterval</td>
                            <td class="text-end font-monospace">@FormatAge(s.OldestPendingAge)</td>
                        </tr>
                    }
                </tbody>
            </table>
        </div>
    }

    @* ── Trends (first KPI-history consumer) ── *@
    <div class="d-flex justify-content-between align-items-center mt-4 mb-2" data-test="notification-trends">
        <h5 class="mb-0">Trends</h5>
        <div class="btn-group btn-group-sm" role="group" aria-label="Trend window">
            <button type="button"
                    class="btn @(_windowHours == 24 ? "btn-primary" : "btn-outline-secondary")"
                    @onclick="() => SetWindowAsync(24)" disabled="@_trendsLoading">24h</button>
            <button type="button"
                    class="btn @(_windowHours == 168 ? "btn-primary" : "btn-outline-secondary")"
                    @onclick="() => SetWindowAsync(168)" disabled="@_trendsLoading">7d</button>
            <button type="button"
                    class="btn @(_windowHours == 720 ? "btn-primary" : "btn-outline-secondary")"
                    @onclick="() => SetWindowAsync(720)" disabled="@_trendsLoading">30d</button>
            <button type="button"
                    class="btn @(_windowHours == 2160 ? "btn-primary" : "btn-outline-secondary")"
                    @onclick="() => SetWindowAsync(2160)" disabled="@_trendsLoading">90d</button>
        </div>
    </div>
    <div class="row g-3">
        <div class="col-lg-4 col-md-6">
            <KpiTrendChart Title="Queue Depth"
                           Points="@_queueDepthSeries"
                           IsAvailable="@_queueDepthAvailable"
                           ErrorMessage="@_queueDepthError" />
        </div>
        <div class="col-lg-4 col-md-6">
            <KpiTrendChart Title="Parked"
                           Points="@_parkedSeries"
                           IsAvailable="@_parkedAvailable"
                           ErrorMessage="@_parkedError" />
        </div>
        <div class="col-lg-4 col-md-6">
            <KpiTrendChart Title="Delivered / interval"
                           Points="@_deliveredSeries"
                           IsAvailable="@_deliveredAvailable"
                           ErrorMessage="@_deliveredError" />
        </div>
    </div>
</div>

@code {
    private List<Site> _sites = new();

    private NotificationKpiResponse _kpi = new(string.Empty, true, null, 0, 0, 0, 0, null);
    private string? _kpiError;

    private IReadOnlyList<SiteNotificationKpiSnapshot> _perSite = Array.Empty<SiteNotificationKpiSnapshot>();
    private string? _perSiteError;

    // ── Per-node (M5.2 per-node stuck-count KPIs) ──
    private IReadOnlyList<NodeNotificationKpiSnapshot> _perNode = Array.Empty<NodeNotificationKpiSnapshot>();
    private string? _perNodeError;

    private bool _loading;

    // ── Trends (first KPI-history consumer) ──
    // Window in hours: 24h (default) or 168h (7d). Toggling re-queries.
    // Per-metric isolation (mirrors the SiteCallsReport pattern): each metric
    // carries its own series + availability + error, each loaded via its own
    // try/catch so one metric's failure only blanks that one chart and the others
    // still render their already-fetched data.
    private int _windowHours = 24;
    private bool _trendsLoading;

    private IReadOnlyList<KpiSeriesPoint>? _queueDepthSeries;
    private bool _queueDepthAvailable = true;
    private string? _queueDepthError;

    private IReadOnlyList<KpiSeriesPoint>? _parkedSeries;
    private bool _parkedAvailable = true;
    private string? _parkedError;

    private IReadOnlyList<KpiSeriesPoint>? _deliveredSeries;
    private bool _deliveredAvailable = true;
    private string? _deliveredError;

    protected override async Task OnInitializedAsync()
    {
        try
        {
            _sites = (await SiteRepository.GetAllSitesAsync()).ToList();
        }
        catch (Exception ex)
        {
            // Non-fatal — the per-site table falls back to raw site identifiers.
            Logger.LogWarning(ex, "Failed to load sites for the KPI per-site breakdown.");
        }

        await RefreshAll();
    }

    private async Task RefreshAll()
    {
        _loading = true;
        // Race-free despite all tasks mutating component fields: Blazor Server runs
        // every continuation on the circuit's single-threaded synchronization context.
        await Task.WhenAll(LoadGlobalKpis(), LoadPerSiteKpis(), LoadPerNodeKpis(), LoadTrends());
        _loading = false;
    }

    private async Task SetWindowAsync(int windowHours)
    {
        if (_windowHours == windowHours)
        {
            return;
        }

        _windowHours = windowHours;
        await LoadTrends();
    }

    private async Task LoadTrends()
    {
        _trendsLoading = true;
        try
        {
            var toUtc = DateTime.UtcNow;
            var fromUtc = toUtc - TimeSpan.FromHours(_windowHours);

            // Per-metric isolation: each series is loaded via its own try/catch so
            // one metric's failure only blanks that one chart while the others still
            // render their fetched data — and a throw never breaks the KPI tiles above.
            (_queueDepthSeries, _queueDepthAvailable, _queueDepthError) =
                await LoadSeries(KpiMetrics.NotificationOutbox.QueueDepth, fromUtc, toUtc);
            (_parkedSeries, _parkedAvailable, _parkedError) =
                await LoadSeries(KpiMetrics.NotificationOutbox.ParkedCount, fromUtc, toUtc);
            (_deliveredSeries, _deliveredAvailable, _deliveredError) =
                await LoadSeries(KpiMetrics.NotificationOutbox.DeliveredLastInterval, fromUtc, toUtc);
        }
        finally
        {
            _trendsLoading = false;
        }
    }

    /// <summary>
    /// Fetch one NotificationOutbox / Global series, swallowing any failure into the
    /// chart's unavailable state. Returns the points (null on failure), the
    /// availability flag, and a short error message for the chart placeholder.
    /// </summary>
    private async Task<(IReadOnlyList<KpiSeriesPoint>? Points, bool Available, string? Error)>
        LoadSeries(string metric, DateTime fromUtc, DateTime toUtc)
    {
        try
        {
            var points = await KpiHistory.GetSeriesAsync(
                KpiSources.NotificationOutbox, metric, KpiScopes.Global, scopeKey: null, fromUtc, toUtc);
            return (points, true, null);
        }
        catch (Exception ex)
        {
            // A KPI-history hiccup must never break the page — the chart degrades to
            // its unavailable placeholder while the KPI tiles above stay rendered.
            Logger.LogWarning(ex, "Failed to load notification-outbox KPI trend series for metric {Metric}.", metric);
            return (null, false, "Trend data unavailable.");
        }
    }

    private async Task LoadGlobalKpis()
    {
        try
        {
            var response = await CommunicationService.GetNotificationKpisAsync(
                new NotificationKpiRequest(Guid.NewGuid().ToString("N")));
            if (response.Success)
            {
                _kpi = response;
                _kpiError = null;
            }
            else
            {
                _kpiError = response.ErrorMessage ?? "KPI query failed.";
            }
        }
        catch (Exception ex)
        {
            _kpiError = $"KPI query failed: {ex.Message}";
        }
    }

    private async Task LoadPerSiteKpis()
    {
        try
        {
            var response = await CommunicationService.GetPerSiteNotificationKpisAsync(
                new PerSiteNotificationKpiRequest(Guid.NewGuid().ToString("N")));
            if (response.Success)
            {
                _perSite = response.Sites;
                _perSiteError = null;
            }
            else
            {
                _perSiteError = response.ErrorMessage ?? "Per-site KPI query failed.";
            }
        }
        catch (Exception ex)
        {
            _perSiteError = $"Per-site KPI query failed: {ex.Message}";
        }
    }

    private async Task LoadPerNodeKpis()
    {
        try
        {
            var response = await CommunicationService.GetPerNodeNotificationKpisAsync(
                new PerNodeNotificationKpiRequest(Guid.NewGuid().ToString("N")));
            if (response.Success)
            {
                _perNode = response.Nodes;
                _perNodeError = null;
            }
            else
            {
                _perNodeError = response.ErrorMessage ?? "Per-node KPI query failed.";
            }
        }
        catch (Exception ex)
        {
            _perNodeError = $"Per-node KPI query failed: {ex.Message}";
        }
    }

    private string SiteName(string siteId) =>
        _sites.FirstOrDefault(s => s.SiteIdentifier == siteId)?.Name ?? siteId;

    private static string FormatAge(TimeSpan? age)
    {
        if (age == null) return "—";
        var t = age.Value;
        if (t.TotalSeconds < 60) return $"{(int)t.TotalSeconds}s";
        if (t.TotalMinutes < 60) return $"{(int)t.TotalMinutes}m";
        if (t.TotalHours < 24) return $"{(int)t.TotalHours}h";
        return $"{(int)t.TotalDays}d";
    }
}