@page "/deployment/topology"
@page "/deployment/instances"
@using ScadaLink.Security
@using ScadaLink.Commons.Entities.Instances
@using ScadaLink.Commons.Entities.Sites
@using ScadaLink.Commons.Entities.Templates
@using ScadaLink.Commons.Entities.Deployment
@using ScadaLink.Commons.Interfaces.Repositories
@using ScadaLink.Commons.Types.Enums
@using ScadaLink.DeploymentManager
@using ScadaLink.TemplateEngine.Services
@attribute [Authorize(Policy = AuthorizationPolicies.RequireDeployment)]
@inject ITemplateEngineRepository TemplateEngineRepository
@inject ISiteRepository SiteRepository
@inject IDeploymentManagerRepository DeploymentManagerRepository
@inject DeploymentService DeploymentService
@inject AreaService AreaService
@inject InstanceService InstanceService
@inject AuthenticationStateProvider AuthStateProvider
@inject NavigationManager NavigationManager
@inject IJSRuntime JSRuntime

<div class="container-fluid mt-3">
    <ToastNotification @ref="_toast" />
    <ConfirmDialog @ref="_confirmDialog" />

    <CreateAreaDialog @bind-IsVisible="_showCreateAreaDialog"
                      RequireSitePicker="_createAreaRequireSitePicker"
                      ContextLabel="@_createAreaContextLabel"
                      SiteId="_createAreaSiteId"
                      ParentAreaId="_createAreaParentId"
                      SiteOptions="EnumerateSiteOptions()"
                      ParentOptions="EnumerateAreaOptionsForCreate()"
                      ErrorMessage="@_createAreaError"
                      OnSubmit="SubmitCreateArea" />

    <MoveAreaDialog @bind-IsVisible="_showMoveAreaDialog"
                    AreaId="_moveAreaId"
                    AreaName="@_moveAreaName"
                    CurrentParentId="_moveAreaCurrentParentId"
                    ParentOptions="EnumerateAreaParentOptionsExcluding(_moveAreaId, _moveAreaSiteId)"
                    ErrorMessage="@_moveAreaError"
                    OnSubmit="SubmitMoveArea" />

    <MoveInstanceDialog @bind-IsVisible="_showMoveInstanceDialog"
                        InstanceId="_moveInstanceId"
                        InstanceName="@_moveInstanceName"
                        CurrentAreaId="_moveInstanceCurrentAreaId"
                        AreaOptions="EnumerateAreaOptionsForSite(_moveInstanceSiteId)"
                        ErrorMessage="@_moveInstanceError"
                        OnSubmit="SubmitMoveInstance" />

    @if (_loading)
    {
        <LoadingSpinner IsLoading="true" />
    }
    else if (_errorMessage != null)
    {
        <div class="alert alert-danger">@_errorMessage</div>
    }
    else
    {
        <h6 class="mb-2">Topology</h6>
        <div class="d-flex align-items-center mb-2 gap-2">
            <input type="text" class="form-control form-control-sm" style="max-width: 320px;"
                   placeholder="Search sites, areas, instances..."
                   @bind="_searchText" @bind:event="oninput" @bind:after="OnSearchChanged" />
            <div class="btn-group btn-group-sm">
                <button class="btn btn-outline-secondary" @onclick="OpenCreateAreaDialogRoot">+ Area</button>
                <button class="btn btn-outline-secondary"
                        @onclick='() => NavigationManager.NavigateTo("/deployment/instances/create")'>+ Instance</button>
                <button class="btn btn-outline-secondary" @onclick="LoadDataAsync">Refresh</button>
                <button class="btn btn-outline-secondary" @onclick="() => _tree?.ExpandAll()">Expand</button>
                <button class="btn btn-outline-secondary" @onclick="() => _tree?.CollapseAll()">Collapse</button>
            </div>
        </div>

        <div style="max-height: calc(100vh - 180px); overflow-y: auto; padding: 4px;">
            <TreeView @ref="_tree" TItem="TopoNode" Items="_treeRoots"
                      ChildrenSelector="n => n.Children"
                      HasChildrenSelector="n => n.Children.Count > 0"
                      KeySelector="n => (object)n.Key"
                      StorageKey="topology-tree"
                      Selectable="true"
                      SelectedKey="_selectedKey"
                      SelectedKeyChanged="OnTreeNodeSelected">
                <NodeContent Context="node">
                    @RenderNodeLabel(node)
                </NodeContent>
                <ContextMenu Context="node">
                    @RenderNodeContextMenu(node)
                </ContextMenu>
                <EmptyContent>
                    <span class="text-muted fst-italic">No sites configured. Add sites under Admin → Sites.</span>
                </EmptyContent>
            </TreeView>
        </div>

        <div class="text-muted small mt-2">
            @_allInstances.Count instance(s) across @_sites.Count site(s).
        </div>

        @* Diff Modal — ported from Instances.razor *@
        @if (_showDiffModal)
        {
            <div class="modal d-block" tabindex="-1" style="background-color: rgba(0,0,0,0.5);">
                <div class="modal-dialog modal-lg">
                    <div class="modal-content">
                        <div class="modal-header">
                            <h5 class="modal-title">Deployment Diff — @_diffInstanceName</h5>
                            <button type="button" class="btn-close" @onclick="() => _showDiffModal = false"></button>
                        </div>
                        <div class="modal-body">
                            @if (_diffLoading)
                            {
                                <LoadingSpinner IsLoading="true" />
                            }
                            else if (_diffError != null)
                            {
                                <div class="alert alert-danger">@_diffError</div>
                            }
                            else if (_diffResult != null)
                            {
                                <div class="mb-2">
                                    <span class="badge @(_diffResult.IsStale ? "bg-warning text-dark" : "bg-success")">
                                        @(_diffResult.IsStale ? "Stale — changes pending" : "Current")
                                    </span>
                                    <span class="text-muted small ms-2">
                                        Deployed: @_diffResult.DeployedRevisionHash[..8]
                                        | Current: @_diffResult.CurrentRevisionHash[..8]
                                        | Deployed at: @_diffResult.DeployedAt.LocalDateTime.ToString("yyyy-MM-dd HH:mm")
                                    </span>
                                </div>
                                @if (!_diffResult.IsStale)
                                {
                                    <p class="text-muted">No differences between deployed and current configuration.</p>
                                }
                                else
                                {
                                    <p class="text-muted small">The deployed revision hash differs from the current template-derived hash. Redeploy to apply changes.</p>
                                }
                            }
                        </div>
                        <div class="modal-footer">
                            <button class="btn btn-secondary btn-sm" @onclick="() => _showDiffModal = false">Close</button>
                        </div>
                    </div>
                </div>
            </div>
        }
    }
</div>

@code {
    // ---- Data ----
    private List<Instance> _allInstances = new();
    private List<Site> _sites = new();
    private List<Template> _templates = new();
    private List<Area> _allAreas = new();
    private Dictionary<int, bool> _stalenessMap = new();

    private bool _loading = true;
    private string? _errorMessage;
    private bool _actionInProgress;

    private string _searchText = string.Empty;

    private ToastNotification _toast = default!;
    private ConfirmDialog _confirmDialog = default!;

    private TreeView<TopoNode> _tree = default!;
    private object? _selectedKey;
    private const string SelectedKeyStorage = "topology-tree-selected";

    // ---- Tree model ----
    private enum TopoNodeKind { Site, Area, Instance }

    private record TopoNode(
        string Key,
        TopoNodeKind Kind,
        int EntityId,
        int SiteId,
        string Label,
        Site? Site,
        Area? Area,
        Instance? Instance,
        bool IsStale,
        bool MatchesSearch,
        List<TopoNode> Children);

    private List<TopoNode> _treeRoots = new();

    // ---- Inline rename ----
    private string? _renamingKey;
    private string _renameBuffer = string.Empty;
    private string? _renameError;

    // ---- Lifecycle ----
    protected override async Task OnInitializedAsync()
    {
        await LoadDataAsync();
    }

    protected override async Task OnAfterRenderAsync(bool firstRender)
    {
        if (firstRender)
        {
            try
            {
                var stored = await JSRuntime.InvokeAsync<string?>("treeviewStorage.load", SelectedKeyStorage);
                if (!string.IsNullOrEmpty(stored))
                {
                    _selectedKey = stored;
                    StateHasChanged();
                }
            }
            catch { /* no JS interop available (prerender, tests) — ignore */ }
        }
    }

    private async Task LoadDataAsync()
    {
        _loading = true;
        _errorMessage = null;
        try
        {
            _allInstances = (await TemplateEngineRepository.GetAllInstancesAsync()).ToList();
            _sites = (await SiteRepository.GetAllSitesAsync()).ToList();
            _templates = (await TemplateEngineRepository.GetAllTemplatesAsync()).ToList();

            _allAreas.Clear();
            foreach (var site in _sites)
            {
                var areas = await TemplateEngineRepository.GetAreasBySiteIdAsync(site.Id);
                _allAreas.AddRange(areas);
            }

            _stalenessMap.Clear();
            foreach (var inst in _allInstances.Where(i => i.State != InstanceState.NotDeployed))
            {
                try
                {
                    var comparison = await DeploymentService.GetDeploymentComparisonAsync(inst.Id);
                    _stalenessMap[inst.Id] = comparison.IsSuccess && comparison.Value.IsStale;
                }
                catch
                {
                    _stalenessMap[inst.Id] = false;
                }
            }

            BuildTree();
        }
        catch (Exception ex)
        {
            _errorMessage = $"Failed to load topology: {ex.Message}";
        }
        _loading = false;
    }

    private void OnSearchChanged()
    {
        BuildTree();
    }

    private bool NodeMatchesSearch(string label)
    {
        if (string.IsNullOrWhiteSpace(_searchText)) return true;
        return label.Contains(_searchText, StringComparison.OrdinalIgnoreCase);
    }

    private void BuildTree()
    {
        _treeRoots = _sites
            .OrderBy(s => s.Name, StringComparer.OrdinalIgnoreCase)
            .Select(site =>
            {
                var siteAreas = _allAreas.Where(a => a.SiteId == site.Id).ToList();
                var siteInstances = _allInstances.Where(i => i.SiteId == site.Id).ToList();

                var areaChildren = BuildAreaNodes(siteAreas, siteInstances, parentId: null);
                var rootInstances = siteInstances
                    .Where(i => i.AreaId == null)
                    .OrderBy(i => i.UniqueName, StringComparer.OrdinalIgnoreCase)
                    .Select(MakeInstanceNode)
                    .ToList();

                var children = areaChildren.Concat(rootInstances).ToList();

                return new TopoNode(
                    Key: $"s:{site.Id}",
                    Kind: TopoNodeKind.Site,
                    EntityId: site.Id,
                    SiteId: site.Id,
                    Label: site.Name,
                    Site: site,
                    Area: null,
                    Instance: null,
                    IsStale: false,
                    MatchesSearch: NodeMatchesSearch(site.Name),
                    Children: children);
            })
            .ToList();
    }

    private List<TopoNode> BuildAreaNodes(List<Area> allAreas, List<Instance> instances, int? parentId)
    {
        return allAreas
            .Where(a => a.ParentAreaId == parentId)
            .OrderBy(a => a.Name, StringComparer.OrdinalIgnoreCase)
            .Select(area =>
            {
                var childAreas = BuildAreaNodes(allAreas, instances, area.Id);
                var areaInstances = instances
                    .Where(i => i.AreaId == area.Id)
                    .OrderBy(i => i.UniqueName, StringComparer.OrdinalIgnoreCase)
                    .Select(MakeInstanceNode)
                    .ToList();
                var children = childAreas.Concat(areaInstances).ToList();
                return new TopoNode(
                    Key: $"a:{area.Id}",
                    Kind: TopoNodeKind.Area,
                    EntityId: area.Id,
                    SiteId: area.SiteId,
                    Label: area.Name,
                    Site: null,
                    Area: area,
                    Instance: null,
                    IsStale: false,
                    MatchesSearch: NodeMatchesSearch(area.Name),
                    Children: children);
            })
            .ToList();
    }

    private TopoNode MakeInstanceNode(Instance inst) => new(
        Key: $"i:{inst.Id}",
        Kind: TopoNodeKind.Instance,
        EntityId: inst.Id,
        SiteId: inst.SiteId,
        Label: inst.UniqueName,
        Site: null,
        Area: null,
        Instance: inst,
        IsStale: _stalenessMap.GetValueOrDefault(inst.Id),
        MatchesSearch: NodeMatchesSearch(inst.UniqueName),
        Children: new List<TopoNode>());

    // ---- Rendering ----
    private RenderFragment RenderNodeLabel(TopoNode node) => __builder =>
    {
        var dim = !string.IsNullOrWhiteSpace(_searchText) && !SubtreeContainsMatch(node);
        var labelStyle = dim ? "opacity: 0.4;" : null;

        switch (node.Kind)
        {
            case TopoNodeKind.Site:
                <span class="tv-glyph" style="@labelStyle"><i class="bi bi-building"></i></span>
                <span class="tv-label fw-semibold" style="@labelStyle" title="@node.Label">@node.Label</span>
                break;

            case TopoNodeKind.Area:
                <span class="tv-glyph" style="@labelStyle"><i class="bi bi-diagram-3"></i></span>
                @if (_renamingKey == node.Key)
                {
                    <input class="form-control form-control-sm d-inline-block" style="width: auto; max-width: 220px;"
                           @ref="_renameInput"
                           @bind="_renameBuffer"
                           @onkeydown="(e) => OnRenameKeyDown(e, node)"
                           @onblur="() => CancelRename()" />
                    @if (!string.IsNullOrEmpty(_renameError))
                    {
                        <span class="text-danger small ms-2">@_renameError</span>
                    }
                }
                else
                {
                    <span class="tv-label" style="@labelStyle" title="@node.Label"
                          @ondblclick="() => BeginRename(node)">@node.Label</span>
                }
                break;

            case TopoNodeKind.Instance:
                <span class="tv-glyph" style="@labelStyle"><i class="bi bi-box"></i></span>
                <span class="tv-label" style="@labelStyle" title="@node.Label">@node.Label</span>
                <span class="badge @GetStateBadge(node.Instance!.State) ms-1" style="@labelStyle">@node.Instance!.State</span>
                @if (node.Instance!.State != InstanceState.NotDeployed)
                {
                    <span class="badge @(node.IsStale ? "bg-warning text-dark" : "bg-light text-dark") ms-1" style="@labelStyle">
                        @(node.IsStale ? "Stale" : "Current")
                    </span>
                }
                break;
        }
    };

    private static bool SubtreeContainsMatch(TopoNode node)
    {
        if (node.MatchesSearch) return true;
        return node.Children.Any(SubtreeContainsMatch);
    }

    private RenderFragment RenderNodeContextMenu(TopoNode node) => __builder =>
    {
        switch (node.Kind)
        {
            case TopoNodeKind.Site:
                <button class="dropdown-item" @onclick="() => OpenCreateAreaDialogForSite(node.EntityId)">Add Area</button>
                <button class="dropdown-item"
                        @onclick='() => NavigationManager.NavigateTo($"/deployment/instances/create?siteId={node.EntityId}")'>
                    Create Instance here
                </button>
                break;

            case TopoNodeKind.Area:
                <button class="dropdown-item" @onclick="() => OpenCreateAreaDialogForArea(node.SiteId, node.EntityId, node.Label)">Add Sub-area</button>
                <button class="dropdown-item"
                        @onclick='() => NavigationManager.NavigateTo($"/deployment/instances/create?siteId={node.SiteId}&areaId={node.EntityId}")'>
                    Create Instance here
                </button>
                <button class="dropdown-item" @onclick="() => OpenMoveAreaDialog(node)">Move to Area…</button>
                <button class="dropdown-item" @onclick="() => BeginRename(node)">Rename…</button>
                <div class="dropdown-divider"></div>
                <button class="dropdown-item text-danger" @onclick="() => DeleteArea(node)" disabled="@_actionInProgress">Delete</button>
                break;

            case TopoNodeKind.Instance:
                var inst = node.Instance!;
                var isStale = node.IsStale;
                <button class="dropdown-item" @onclick="() => DeployInstance(inst)"
                        disabled="@_actionInProgress">@(isStale ? "Redeploy" : "Deploy")</button>
                @if (inst.State == InstanceState.Enabled)
                {
                    <button class="dropdown-item" @onclick="() => DisableInstance(inst)"
                            disabled="@_actionInProgress">Disable</button>
                }
                else if (inst.State == InstanceState.Disabled)
                {
                    <button class="dropdown-item" @onclick="() => EnableInstance(inst)"
                            disabled="@_actionInProgress">Enable</button>
                }
                <button class="dropdown-item"
                        @onclick='() => NavigationManager.NavigateTo($"/deployment/instances/{inst.Id}/configure")'>
                    Configure
                </button>
                <button class="dropdown-item" @onclick="() => ShowDiff(inst)"
                        disabled="@(_actionInProgress || inst.State == InstanceState.NotDeployed)">Diff</button>
                <button class="dropdown-item" @onclick="() => OpenMoveInstanceDialog(node)">Move to Area…</button>
                <div class="dropdown-divider"></div>
                <button class="dropdown-item text-danger" @onclick="() => DeleteInstance(inst)"
                        disabled="@_actionInProgress">Delete</button>
                break;
        }
    };

    private static string GetStateBadge(InstanceState state) => state switch
    {
        InstanceState.Enabled => "bg-success",
        InstanceState.Disabled => "bg-secondary",
        InstanceState.NotDeployed => "bg-light text-dark",
        _ => "bg-secondary"
    };

    // ---- Selection ----
    private async Task OnTreeNodeSelected(object? key)
    {
        _selectedKey = key;
        try
        {
            await JSRuntime.InvokeVoidAsync("treeviewStorage.save", SelectedKeyStorage,
                key?.ToString() ?? string.Empty);
        }
        catch { /* ignore */ }
    }

    // ---- Inline rename ----
    private ElementReference _renameInput;

    private void BeginRename(TopoNode node)
    {
        if (node.Kind != TopoNodeKind.Area) return;
        _renamingKey = node.Key;
        _renameBuffer = node.Label;
        _renameError = null;
    }

    private void CancelRename()
    {
        _renamingKey = null;
        _renameBuffer = string.Empty;
        _renameError = null;
    }

    private async Task OnRenameKeyDown(KeyboardEventArgs e, TopoNode node)
    {
        if (e.Key == "Escape")
        {
            CancelRename();
        }
        else if (e.Key == "Enter")
        {
            await CommitRename(node);
        }
    }

    private async Task CommitRename(TopoNode node)
    {
        if (string.IsNullOrWhiteSpace(_renameBuffer) || _renameBuffer.Trim() == node.Label)
        {
            CancelRename();
            return;
        }

        var user = await GetCurrentUserAsync();
        var result = await AreaService.UpdateAreaAsync(node.EntityId, _renameBuffer.Trim(), user);
        if (result.IsSuccess)
        {
            CancelRename();
            _toast.ShowSuccess($"Area renamed to '{result.Value.Name}'.");
            await LoadDataAsync();
        }
        else
        {
            _renameError = result.Error;
        }
    }

    // ---- Create-area dialog ----
    private bool _showCreateAreaDialog;
    private bool _createAreaRequireSitePicker;
    private string _createAreaContextLabel = string.Empty;
    private int? _createAreaSiteId;
    private int? _createAreaParentId;
    private string? _createAreaError;

    private void OpenCreateAreaDialogRoot()
    {
        _createAreaRequireSitePicker = true;
        _createAreaContextLabel = string.Empty;
        _createAreaSiteId = null;
        _createAreaParentId = null;
        _createAreaError = null;
        _showCreateAreaDialog = true;
    }

    private void OpenCreateAreaDialogForSite(int siteId)
    {
        var site = _sites.FirstOrDefault(s => s.Id == siteId);
        _createAreaRequireSitePicker = false;
        _createAreaContextLabel = $"Site: {site?.Name ?? $"#{siteId}"} (root)";
        _createAreaSiteId = siteId;
        _createAreaParentId = null;
        _createAreaError = null;
        _showCreateAreaDialog = true;
    }

    private void OpenCreateAreaDialogForArea(int siteId, int parentAreaId, string parentLabel)
    {
        var site = _sites.FirstOrDefault(s => s.Id == siteId);
        _createAreaRequireSitePicker = false;
        _createAreaContextLabel = $"Site: {site?.Name ?? $"#{siteId}"} → Parent: {parentLabel}";
        _createAreaSiteId = siteId;
        _createAreaParentId = parentAreaId;
        _createAreaError = null;
        _showCreateAreaDialog = true;
    }

    private async Task SubmitCreateArea((int SiteId, int? ParentAreaId, string Name) req)
    {
        _createAreaError = null;
        if (req.SiteId == 0) { _createAreaError = "Select a site."; return; }
        if (string.IsNullOrWhiteSpace(req.Name)) { _createAreaError = "Area name is required."; return; }

        var user = await GetCurrentUserAsync();
        var result = await AreaService.CreateAreaAsync(req.Name, req.SiteId, req.ParentAreaId, user);
        if (result.IsSuccess)
        {
            _showCreateAreaDialog = false;
            _toast.ShowSuccess($"Area '{result.Value.Name}' created.");
            await LoadDataAsync();
        }
        else
        {
            _createAreaError = result.Error;
        }
    }

    // ---- Move-area dialog ----
    private bool _showMoveAreaDialog;
    private int _moveAreaId;
    private string _moveAreaName = string.Empty;
    private int _moveAreaSiteId;
    private int? _moveAreaCurrentParentId;
    private string? _moveAreaError;

    private void OpenMoveAreaDialog(TopoNode node)
    {
        _moveAreaId = node.EntityId;
        _moveAreaName = node.Label;
        _moveAreaSiteId = node.SiteId;
        _moveAreaCurrentParentId = node.Area?.ParentAreaId;
        _moveAreaError = null;
        _showMoveAreaDialog = true;
    }

    private async Task SubmitMoveArea((int AreaId, int? NewParentId) req)
    {
        _moveAreaError = null;
        var user = await GetCurrentUserAsync();
        var result = await AreaService.MoveAreaAsync(req.AreaId, req.NewParentId, user);
        if (result.IsSuccess)
        {
            _showMoveAreaDialog = false;
            _toast.ShowSuccess($"Area '{_moveAreaName}' moved.");
            await LoadDataAsync();
        }
        else
        {
            _moveAreaError = result.Error;
        }
    }

    // ---- Move-instance dialog ----
    private bool _showMoveInstanceDialog;
    private int _moveInstanceId;
    private string _moveInstanceName = string.Empty;
    private int _moveInstanceSiteId;
    private int? _moveInstanceCurrentAreaId;
    private string? _moveInstanceError;

    private void OpenMoveInstanceDialog(TopoNode node)
    {
        var inst = node.Instance!;
        _moveInstanceId = inst.Id;
        _moveInstanceName = inst.UniqueName;
        _moveInstanceSiteId = inst.SiteId;
        _moveInstanceCurrentAreaId = inst.AreaId;
        _moveInstanceError = null;
        _showMoveInstanceDialog = true;
    }

    private async Task SubmitMoveInstance((int InstanceId, int? NewAreaId) req)
    {
        _moveInstanceError = null;
        var user = await GetCurrentUserAsync();
        var result = await InstanceService.AssignToAreaAsync(req.InstanceId, req.NewAreaId, user);
        if (result.IsSuccess)
        {
            _showMoveInstanceDialog = false;
            _toast.ShowSuccess($"Instance '{_moveInstanceName}' moved.");
            await LoadDataAsync();
        }
        else
        {
            _moveInstanceError = result.Error;
        }
    }

    // ---- Area & instance deletion ----
    private async Task DeleteArea(TopoNode node)
    {
        var confirmed = await _confirmDialog.ShowAsync(
            $"Delete area '{node.Label}'? This will fail if it has sub-areas or assigned instances.",
            "Delete Area");
        if (!confirmed) return;

        _actionInProgress = true;
        var user = await GetCurrentUserAsync();
        var result = await AreaService.DeleteAreaAsync(node.EntityId, user);
        if (result.IsSuccess)
        {
            _toast.ShowSuccess($"Area '{node.Label}' deleted.");
            await LoadDataAsync();
        }
        else
        {
            _toast.ShowError(result.Error);
        }
        _actionInProgress = false;
    }

    private async Task DeleteInstance(Instance inst)
    {
        var confirmed = await _confirmDialog.ShowAsync(
            $"Delete instance '{inst.UniqueName}'? This will remove it from the site. Store-and-forward messages will NOT be cleared.",
            "Delete Instance");
        if (!confirmed) return;

        _actionInProgress = true;
        try
        {
            var user = await GetCurrentUserAsync();
            var result = await DeploymentService.DeleteInstanceAsync(inst.Id, user);
            if (result.IsSuccess)
            {
                _toast.ShowSuccess($"Instance '{inst.UniqueName}' deleted.");
                await LoadDataAsync();
            }
            else
            {
                _toast.ShowError($"Delete failed: {result.Error}");
            }
        }
        catch (Exception ex)
        {
            _toast.ShowError($"Delete failed: {ex.Message}");
        }
        _actionInProgress = false;
    }

    // ---- Lifecycle actions ----
    private async Task EnableInstance(Instance inst)
    {
        _actionInProgress = true;
        try
        {
            var user = await GetCurrentUserAsync();
            var result = await DeploymentService.EnableInstanceAsync(inst.Id, user);
            if (result.IsSuccess)
            {
                _toast.ShowSuccess($"Instance '{inst.UniqueName}' enabled.");
                await LoadDataAsync();
            }
            else
            {
                _toast.ShowError($"Enable failed: {result.Error}");
            }
        }
        catch (Exception ex)
        {
            _toast.ShowError($"Enable failed: {ex.Message}");
        }
        _actionInProgress = false;
    }

    private async Task DisableInstance(Instance inst)
    {
        var confirmed = await _confirmDialog.ShowAsync(
            $"Disable instance '{inst.UniqueName}'? The instance actor will be stopped.",
            "Disable Instance");
        if (!confirmed) return;

        _actionInProgress = true;
        try
        {
            var user = await GetCurrentUserAsync();
            var result = await DeploymentService.DisableInstanceAsync(inst.Id, user);
            if (result.IsSuccess)
            {
                _toast.ShowSuccess($"Instance '{inst.UniqueName}' disabled.");
                await LoadDataAsync();
            }
            else
            {
                _toast.ShowError($"Disable failed: {result.Error}");
            }
        }
        catch (Exception ex)
        {
            _toast.ShowError($"Disable failed: {ex.Message}");
        }
        _actionInProgress = false;
    }

    private async Task DeployInstance(Instance inst)
    {
        _actionInProgress = true;
        try
        {
            var user = await GetCurrentUserAsync();
            var result = await DeploymentService.DeployInstanceAsync(inst.Id, user);
            if (result.IsSuccess)
            {
                _toast.ShowSuccess($"Instance '{inst.UniqueName}' deployed (revision {result.Value.RevisionHash?[..8]}).");
                await LoadDataAsync();
            }
            else
            {
                _toast.ShowError($"Deploy failed: {result.Error}");
            }
        }
        catch (Exception ex)
        {
            _toast.ShowError($"Deploy failed: {ex.Message}");
        }
        _actionInProgress = false;
    }

    // ---- Diff modal ----
    private bool _showDiffModal;
    private bool _diffLoading;
    private string? _diffError;
    private string _diffInstanceName = string.Empty;
    private DeploymentComparisonResult? _diffResult;

    private async Task ShowDiff(Instance inst)
    {
        _showDiffModal = true;
        _diffLoading = true;
        _diffError = null;
        _diffResult = null;
        _diffInstanceName = inst.UniqueName;
        try
        {
            var result = await DeploymentService.GetDeploymentComparisonAsync(inst.Id);
            if (result.IsSuccess)
            {
                _diffResult = result.Value;
            }
            else
            {
                _diffError = result.Error;
            }
        }
        catch (Exception ex)
        {
            _diffError = $"Failed to load diff: {ex.Message}";
        }
        _diffLoading = false;
    }

    // ---- Dropdown option helpers ----
    private IEnumerable<(int Id, string Label)> EnumerateSiteOptions()
    {
        foreach (var s in _sites.OrderBy(s => s.Name, StringComparer.OrdinalIgnoreCase))
            yield return (s.Id, s.Name);
    }

    private IEnumerable<(int Id, string Label, int SiteId)> EnumerateAreaOptionsForCreate()
    {
        foreach (var a in WalkAllSiteAreas())
            yield return a;
    }

    private IEnumerable<(int Id, string Label, int SiteId)> WalkAllSiteAreas()
    {
        foreach (var site in _sites.OrderBy(s => s.Name, StringComparer.OrdinalIgnoreCase))
        {
            foreach (var entry in WalkSiteHierarchy(site.Id, parentId: null, depth: 0, excludeAreaId: null))
                yield return entry;
        }
    }

    private IEnumerable<(int? Id, string Label)> EnumerateAreaOptionsForSite(int siteId)
    {
        yield return ((int?)null, "(No area — site root)");
        foreach (var entry in WalkSiteHierarchy(siteId, parentId: null, depth: 0, excludeAreaId: null))
            yield return ((int?)entry.Id, entry.Label);
    }

    private IEnumerable<(int? Id, string Label)> EnumerateAreaParentOptionsExcluding(int areaId, int siteId)
    {
        yield return ((int?)null, "(Site root)");
        foreach (var entry in WalkSiteHierarchy(siteId, parentId: null, depth: 0, excludeAreaId: areaId))
            yield return ((int?)entry.Id, entry.Label);
    }

    private IEnumerable<(int Id, string Label, int SiteId)> WalkSiteHierarchy(int siteId, int? parentId, int depth, int? excludeAreaId)
    {
        var levelAreas = _allAreas
            .Where(a => a.SiteId == siteId && a.ParentAreaId == parentId)
            .OrderBy(a => a.Name, StringComparer.OrdinalIgnoreCase);

        foreach (var a in levelAreas)
        {
            if (excludeAreaId.HasValue && a.Id == excludeAreaId.Value) continue;
            yield return (a.Id, new string(' ', depth * 2) + a.Name, siteId);
            foreach (var sub in WalkSiteHierarchy(siteId, a.Id, depth + 1, excludeAreaId))
                yield return sub;
        }
    }

    private async Task<string> GetCurrentUserAsync()
    {
        var authState = await AuthStateProvider.GetAuthenticationStateAsync();
        return authState.User.FindFirst("Username")?.Value ?? "unknown";
    }
}