@page "/deployment/debug-view"
@using ScadaLink.Security
@using ScadaLink.Commons.Entities.Instances
@using ScadaLink.Commons.Entities.Sites
@using ScadaLink.Commons.Interfaces.Repositories
@using ScadaLink.Commons.Messages.DebugView
@using ScadaLink.Commons.Messages.Streaming
@using ScadaLink.Commons.Types
@using ScadaLink.Commons.Types.Enums
@using ScadaLink.Communication
@attribute [Authorize(Policy = AuthorizationPolicies.RequireDeployment)]
@inject ITemplateEngineRepository TemplateEngineRepository
@inject ISiteRepository SiteRepository
@inject ScadaLink.CentralUI.Auth.SiteScopeService SiteScope
@inject DebugStreamService DebugStreamService
@inject IJSRuntime JS
@implements IDisposable

<div class="container-fluid mt-3">
    <h4 class="mb-3">Debug View</h4>

    <ToastNotification @ref="_toast" />

    @if (_loading)
    {
        <LoadingSpinner IsLoading="true" />
    }
    else
    {
        @* Status strip — connection state, instance, last snapshot. *@
        <div class="alert alert-light py-2 mb-3 d-flex justify-content-between align-items-center small flex-wrap gap-2">
            <div class="d-flex align-items-center gap-2">
                <strong>
                    @if (_connected)
                    {
                        var inst = _siteInstances.FirstOrDefault(i => i.Id == _selectedInstanceId);
                        @(inst?.UniqueName ?? "Connected")
                    }
                    else
                    {
                        <span class="text-muted">Not connected</span>
                    }
                </strong>
                @if (_connected)
                {
                    <span class="badge bg-success" aria-label="Connection state: Live">
                        <span class="spinner-grow spinner-grow-sm me-1" style="width: 0.5rem; height: 0.5rem;" aria-hidden="true"></span>
                        Live
                    </span>
                }
                else
                {
                    <span class="badge bg-secondary" aria-label="Connection state: Disconnected">Disconnected</span>
                }
            </div>
            <div class="d-flex align-items-center gap-2">
                @if (_snapshot != null)
                {
                    <span class="text-muted">
                        Last snapshot: @_snapshot.SnapshotTimestamp.LocalDateTime.ToString("HH:mm:ss")
                    </span>
                }
                @if (_connected && _connectedFromStorage)
                {
                    <button class="btn btn-outline-secondary btn-sm" @onclick="StartFresh"
                            aria-label="Clear persisted selection and disconnect">Start fresh</button>
                }
            </div>
        </div>

        <div class="row mb-3 g-2">
            <div class="col-md-3">
                <label class="form-label small">Site</label>
                <select class="form-select form-select-sm" @bind="_selectedSiteId" @bind:after="LoadInstancesForSite" disabled="@_connected">
                    <option value="0">Select site...</option>
                    @foreach (var site in _sites)
                    {
                        <option value="@site.Id">@site.Name (@site.SiteIdentifier)</option>
                    }
                </select>
            </div>
            <div class="col-md-4">
                <label class="form-label small">Instance</label>
                <select class="form-select form-select-sm" @bind="_selectedInstanceId" @bind:after="OnInstanceSelectionChanged" disabled="@_connected">
                    <option value="0">Select instance...</option>
                    @foreach (var inst in _siteInstances)
                    {
                        <option value="@inst.Id">@inst.UniqueName (@inst.State)</option>
                    }
                </select>
            </div>
            <div class="col-md-3 d-flex align-items-end gap-2">
                @if (!_connected)
                {
                    <button class="btn btn-primary btn-sm" @onclick="Connect"
                            disabled="@(_selectedInstanceId == 0 || _selectedSiteId == 0 || _connecting)">
                        @if (_connecting) { <span class="spinner-border spinner-border-sm me-1" role="status" aria-label="Connecting"></span> }
                        Connect
                    </button>
                }
                else
                {
                    <button class="btn btn-outline-danger btn-sm" @onclick="Disconnect">Disconnect</button>
                }
            </div>
        </div>

        @if (_connected && _snapshot != null)
        {
            <div class="row">
                @* Attribute Values *@
                <div class="col-md-7">
                    <div class="card">
                        <div class="card-header py-2 d-flex justify-content-between align-items-center flex-wrap gap-2">
                            <div class="d-flex align-items-center gap-2">
                                <strong>Attribute Values</strong>
                                <small class="text-muted">@FilteredAttributeValues.Count latest (cap @MaxRows)</small>
                            </div>
                            <div class="d-flex align-items-center gap-2">
                                <input type="text" class="form-control form-control-sm"
                                       style="max-width: 240px;"
                                       placeholder="Filter by attribute…"
                                       @bind="_attrFilter" @bind:event="oninput" aria-label="Filter attributes" />
                                <button class="btn btn-link btn-sm py-0" type="button"
                                        @onclick="() => _attrScrollLocked = !_attrScrollLocked"
                                        aria-pressed="@(_attrScrollLocked ? "true" : "false")"
                                        aria-label="@(_attrScrollLocked ? "Scroll locked" : "Auto-scroll enabled")">
                                    @(_attrScrollLocked ? "🔒 Locked" : "🔓 Auto-scroll")
                                </button>
                                <button class="btn btn-outline-secondary btn-sm" type="button"
                                        @onclick="ClearAttributes" aria-label="Clear attribute table">Clear</button>
                            </div>
                        </div>
                        <div class="card-body p-0" style="max-height: 500px; overflow-y: auto;">
                            <table class="table table-sm table-striped mb-0">
                                <thead class="table-light sticky-top">
                                    <tr>
                                        <th>Attribute</th>
                                        <th>Value</th>
                                        <th>Quality</th>
                                        <th>Timestamp</th>
                                    </tr>
                                </thead>
                                <tbody aria-live="polite" aria-atomic="false">
                                    @foreach (var av in FilteredAttributeValues)
                                    {
                                        <tr>
                                            <td class="small">@av.AttributeName</td>
                                            <td class="small font-monospace"><strong>@ValueFormatter.FormatDisplayValue(av.Value)</strong></td>
                                            <td>
                                                <span class="badge @GetQualityBadge(av.Quality)"
                                                      aria-label="@($"Quality: {av.Quality}")">@av.Quality</span>
                                            </td>
                                            <td class="small text-muted"
                                                title="@av.Timestamp.LocalDateTime.ToString("HH:mm:ss.fff")">
                                                @av.Timestamp.LocalDateTime.ToString("HH:mm:ss")
                                            </td>
                                        </tr>
                                    }
                                </tbody>
                            </table>
                        </div>
                    </div>
                </div>

                @* Alarm States *@
                <div class="col-md-5">
                    <div class="card">
                        <div class="card-header py-2 d-flex justify-content-between align-items-center flex-wrap gap-2">
                            <div class="d-flex align-items-center gap-2">
                                <strong>Alarm States</strong>
                                <small class="text-muted">@FilteredAlarmStates.Count latest (cap @MaxRows)</small>
                            </div>
                            <div class="d-flex align-items-center gap-2">
                                <input type="text" class="form-control form-control-sm"
                                       style="max-width: 240px;"
                                       placeholder="Filter by alarm…"
                                       @bind="_alarmFilter" @bind:event="oninput" aria-label="Filter alarms" />
                                <button class="btn btn-link btn-sm py-0" type="button"
                                        @onclick="() => _alarmScrollLocked = !_alarmScrollLocked"
                                        aria-pressed="@(_alarmScrollLocked ? "true" : "false")"
                                        aria-label="@(_alarmScrollLocked ? "Scroll locked" : "Auto-scroll enabled")">
                                    @(_alarmScrollLocked ? "🔒 Locked" : "🔓 Auto-scroll")
                                </button>
                                <button class="btn btn-outline-secondary btn-sm" type="button"
                                        @onclick="ClearAlarms" aria-label="Clear alarm table">Clear</button>
                            </div>
                        </div>
                        <div class="card-body p-0" style="max-height: 500px; overflow-y: auto;">
                            <table class="table table-sm table-striped mb-0">
                                <thead class="table-light sticky-top">
                                    <tr>
                                        <th>Alarm</th>
                                        <th>State</th>
                                        <th>Level</th>
                                        <th>Priority</th>
                                        <th>Timestamp</th>
                                    </tr>
                                </thead>
                                <tbody aria-live="polite" aria-atomic="false">
                                    @foreach (var alarm in FilteredAlarmStates)
                                    {
                                        <tr class="@GetAlarmRowClass(alarm.State)"
                                            title="@(string.IsNullOrEmpty(alarm.Message) ? null : alarm.Message)">
                                            <td class="small">
                                                @alarm.AlarmName
                                                @if (!string.IsNullOrEmpty(alarm.Message))
                                                {
                                                    <span class="ms-1 text-info" aria-label="Has operator message">💬</span>
                                                }
                                            </td>
                                            <td>
                                                <span class="badge @GetAlarmStateBadge(alarm.State)"
                                                      aria-label="@($"Alarm state: {alarm.State}")">@alarm.State</span>
                                            </td>
                                            <td>
                                                @if (alarm.Level != AlarmLevel.None)
                                                {
                                                    <span class="badge @GetAlarmLevelBadge(alarm.Level)"
                                                          aria-label="@($"Alarm level: {alarm.Level}")">@FormatLevel(alarm.Level)</span>
                                                }
                                                else
                                                {
                                                    <span class="text-muted small">—</span>
                                                }
                                            </td>
                                            <td class="small">@alarm.Priority</td>
                                            <td class="small text-muted"
                                                title="@alarm.Timestamp.LocalDateTime.ToString("HH:mm:ss.fff")">
                                                @alarm.Timestamp.LocalDateTime.ToString("HH:mm:ss")
                                            </td>
                                        </tr>
                                    }
                                </tbody>
                            </table>
                        </div>
                    </div>
                </div>
            </div>
        }
        else if (_connected)
        {
            <LoadingSpinner IsLoading="true" Message="Waiting for snapshot..." />
        }
    }
</div>

@code {
    private const int MaxRows = 200;

    [SupplyParameterFromQuery] public int? SiteId { get; set; }
    [SupplyParameterFromQuery] public int? InstanceId { get; set; }

    private List<Site> _sites = new();
    private List<Instance> _siteInstances = new();
    private int _selectedSiteId;
    private int _selectedInstanceId;
    private bool _loading = true;
    private bool _connected;
    private bool _connecting;
    private bool _connectedFromStorage;

    private DebugViewSnapshot? _snapshot;
    // Keyed dictionaries hold the latest value per attribute/alarm; insertion order
    // is preserved so we can trim the oldest when the count exceeds MaxRows.
    private Dictionary<string, AttributeValueChanged> _attributeValues = new();
    private Dictionary<string, AlarmStateChanged> _alarmStates = new();

    // Filters and scroll-lock state per table.
    private string _attrFilter = string.Empty;
    private string _alarmFilter = string.Empty;
    private bool _attrScrollLocked;
    private bool _alarmScrollLocked;

    private IReadOnlyList<AttributeValueChanged> FilteredAttributeValues =>
        string.IsNullOrWhiteSpace(_attrFilter)
            ? _attributeValues.Values.OrderBy(a => a.AttributeName).ToList()
            : _attributeValues.Values
                .Where(a => a.AttributeName.Contains(_attrFilter, StringComparison.OrdinalIgnoreCase))
                .OrderBy(a => a.AttributeName)
                .ToList();

    private IReadOnlyList<AlarmStateChanged> FilteredAlarmStates =>
        string.IsNullOrWhiteSpace(_alarmFilter)
            ? _alarmStates.Values.OrderBy(a => a.AlarmName).ToList()
            : _alarmStates.Values
                .Where(a => a.AlarmName.Contains(_alarmFilter, StringComparison.OrdinalIgnoreCase))
                .OrderBy(a => a.AlarmName)
                .ToList();

    private DebugStreamSession? _session;
    private ToastNotification _toast = default!;

    private string? _initError;

    protected override async Task OnInitializedAsync()
    {
        try
        {
            // Site scoping (CentralUI-002): a scoped Deployment user may only
            // debug sites they are permitted on.
            _sites = await SiteScope.FilterSitesAsync(await SiteRepository.GetAllSitesAsync());
        }
        catch (Exception ex)
        {
            _initError = $"Failed to load sites: {ex.Message}";
        }
        _loading = false;
    }

    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        if (!firstRender) return;

        if (_initError != null)
        {
            _toast.ShowError(_initError);
            _initError = null;
        }

        if (SiteId is > 0 && InstanceId is > 0)
        {
            _selectedSiteId = SiteId.Value;
            await LoadInstancesForSite();
            if (_siteInstances.Any(i => i.Id == InstanceId.Value))
            {
                _selectedInstanceId = InstanceId.Value;
                await Connect();
            }
            else
            {
                _toast.ShowError("Requested instance is not available for debug streaming.");
            }
            StateHasChanged();
            return;
        }

        var storedSiteId = await JS.InvokeAsync<string>("localStorage.getItem", "debugView.siteId");
        var storedInstanceId = await JS.InvokeAsync<string>("localStorage.getItem", "debugView.instanceId");

        if (!string.IsNullOrEmpty(storedSiteId) && int.TryParse(storedSiteId, out var siteId)
            && !string.IsNullOrEmpty(storedInstanceId) && int.TryParse(storedInstanceId, out var instanceId))
        {
            _selectedSiteId = siteId;
            await LoadInstancesForSite();
            _selectedInstanceId = instanceId;
            _connectedFromStorage = true;
            StateHasChanged();
            await Connect();

            // Auto-reconnect notice — the user didn't initiate this connection.
            var inst = _siteInstances.FirstOrDefault(i => i.Id == instanceId);
            _toast.ShowInfo(
                $"Auto-reconnected to {inst?.UniqueName ?? "instance"} from previous session.",
                autoDismissMs: 8000);
        }
    }

    private async Task LoadInstancesForSite()
    {
        _siteInstances.Clear();
        _selectedInstanceId = 0;
        if (_selectedSiteId == 0) return;
        // Site scoping (CentralUI-002): re-check the claim server-side — a query
        // string or stale localStorage value could name a site outside the grant.
        if (!await SiteScope.IsSiteAllowedAsync(_selectedSiteId))
        {
            _selectedSiteId = 0;
            _toast.ShowError("You are not permitted to debug instances on that site.");
            return;
        }
        try
        {
            _siteInstances = (await TemplateEngineRepository.GetInstancesBySiteIdAsync(_selectedSiteId))
                .Where(i => i.State == InstanceState.Enabled)
                .ToList();
        }
        catch (Exception ex)
        {
            _toast.ShowError($"Failed to load instances: {ex.Message}");
        }
    }

    private void OnInstanceSelectionChanged()
    {
        // No-op; selection is tracked via _selectedInstanceId binding
    }

    private async Task Connect()
    {
        if (_selectedInstanceId == 0 || _selectedSiteId == 0) return;
        _connecting = true;
        try
        {
            var session = await DebugStreamService.StartStreamAsync(
                _selectedInstanceId,
                onEvent: evt =>
                {
                    switch (evt)
                    {
                        case AttributeValueChanged av:
                            UpsertWithCap(_attributeValues, av.AttributeName, av);
                            _ = InvokeAsync(StateHasChanged);
                            break;
                        case AlarmStateChanged al:
                            UpsertWithCap(_alarmStates, al.AlarmName, al);
                            _ = InvokeAsync(StateHasChanged);
                            break;
                    }
                },
                onTerminated: () =>
                {
                    _connected = false;
                    _session = null;
                    _ = InvokeAsync(() =>
                    {
                        _toast.ShowError("Debug stream terminated (site disconnected).");
                        StateHasChanged();
                    });
                });

            _session = session;

            // Populate initial state from snapshot
            _attributeValues.Clear();
            foreach (var av in session.InitialSnapshot.AttributeValues)
                _attributeValues[av.AttributeName] = av;

            _alarmStates.Clear();
            foreach (var al in session.InitialSnapshot.AlarmStates)
                _alarmStates[al.AlarmName] = al;

            _snapshot = session.InitialSnapshot;
            _connected = true;

            // Persist selection to localStorage for auto-reconnect on refresh
            await JS.InvokeVoidAsync("localStorage.setItem", "debugView.siteId", _selectedSiteId.ToString());
            await JS.InvokeVoidAsync("localStorage.setItem", "debugView.instanceId", _selectedInstanceId.ToString());

            var instance = _siteInstances.FirstOrDefault(i => i.Id == _selectedInstanceId);
            _toast.ShowSuccess($"Streaming {instance?.UniqueName ?? "instance"}");
        }
        catch (Exception ex)
        {
            _toast.ShowError($"Connect failed: {ex.Message}");
        }
        _connecting = false;
    }

    private async Task Disconnect()
    {
        if (_session != null)
        {
            DebugStreamService.StopStream(_session.SessionId);
            _session = null;
        }

        // Clear persisted selection — user explicitly disconnected
        await JS.InvokeVoidAsync("localStorage.removeItem", "debugView.siteId");
        await JS.InvokeVoidAsync("localStorage.removeItem", "debugView.instanceId");

        _connected = false;
        _connectedFromStorage = false;
        _snapshot = null;
        _attributeValues.Clear();
        _alarmStates.Clear();
    }

    /// <summary>
    /// Disconnect and forget the persisted selection. Surfaces in the status
    /// strip whenever the page auto-reconnects from localStorage so the user
    /// can opt out of the carry-over session.
    /// </summary>
    private async Task StartFresh()
    {
        await Disconnect();
        _selectedSiteId = 0;
        _selectedInstanceId = 0;
        _siteInstances.Clear();
        _toast.ShowInfo("Cleared previous session — select a site and instance to begin.", autoDismissMs: 5000);
    }

    private void ClearAttributes()
    {
        _attributeValues.Clear();
    }

    private void ClearAlarms()
    {
        _alarmStates.Clear();
    }

    /// <summary>
    /// Replace or insert a value keyed by name, then trim the oldest entries
    /// (queue-style) so the table size never exceeds MaxRows. Dictionary
    /// preserves insertion order, so the first key is always the oldest.
    /// </summary>
    private static void UpsertWithCap<T>(Dictionary<string, T> map, string key, T value)
    {
        map[key] = value;
        while (map.Count > MaxRows)
        {
            var oldest = map.Keys.First();
            map.Remove(oldest);
        }
    }

    private static string GetQualityBadge(string quality) => quality switch
    {
        "Good" => "bg-success",
        "Bad" => "bg-danger",
        "Uncertain" => "bg-warning text-dark",
        _ => "bg-secondary"
    };

    private static string GetAlarmStateBadge(AlarmState state) => state switch
    {
        AlarmState.Active => "bg-danger",
        AlarmState.Normal => "bg-success",
        _ => "bg-secondary"
    };

    private static string GetAlarmRowClass(AlarmState state) => state switch
    {
        AlarmState.Active => "table-danger",
        _ => ""
    };

    /// <summary>
    /// Severity-tinted badge class for HiLo alarm levels. The critical bands
    /// (HighHigh / LowLow) get the danger class; warning bands get amber.
    /// </summary>
    private static string GetAlarmLevelBadge(AlarmLevel level) => level switch
    {
        AlarmLevel.HighHigh or AlarmLevel.LowLow => "bg-danger",
        AlarmLevel.High or AlarmLevel.Low => "bg-warning text-dark",
        _ => "bg-secondary"
    };

    private static string FormatLevel(AlarmLevel level) => level switch
    {
        AlarmLevel.HighHigh => "HiHi",
        AlarmLevel.High => "Hi",
        AlarmLevel.Low => "Lo",
        AlarmLevel.LowLow => "LoLo",
        _ => "—"
    };

    public void Dispose()
    {
        if (_session != null)
        {
            DebugStreamService.StopStream(_session.SessionId);
        }
    }
}