@page "/folder-structure"
@attribute [Authorize]
@inject IUserSessionService Session
@inject IUserContextAccessor UserContext
@inject ISessionManager SessionMgr
@inject IElevationCoordinator Elevation
@inject IFolderStructureService FolderSvc
@inject ICsvValidationService CsvValidation
@rendermode InteractiveServer

<h1 class="page-title">Folder Structure</h1>
<p class="page-subtitle">Create folder hierarchies in a document library from a CSV template.</p>

@if (!Session.HasProfile) { <NoProfilePrompt /> return; }
@if (UserContext.Role < UserRole.TechN1) { <WriteGuard /> return; }

<div class="card">
    <SitePicker Profile="Session.CurrentProfile!" @bind-SelectedSites="_sites" Single="true" />
    <div class="form-row mt-8">
        <LibraryPicker Profile="Session.CurrentProfile!" SiteUrl="@(_sites.FirstOrDefault()?.Url)" @bind-Library="_libraryTitle" Label="Library Title" />
    </div>

    <div class="form-group">
        <label class="form-label">Source</label>
        <div class="flex-row">
            <button class="btn btn-sm @(_mode == InputMode.Csv ? "btn-primary" : "btn-secondary")"
                    type="button" @onclick="() => SetMode(InputMode.Csv)">Upload CSV</button>
            <button class="btn btn-sm @(_mode == InputMode.Builder ? "btn-primary" : "btn-secondary")"
                    type="button" @onclick="() => SetMode(InputMode.Builder)">Build visually</button>
        </div>
    </div>

    @if (_mode == InputMode.Csv)
    {
        <div class="form-group">
            <label class="form-label">CSV File (Level1, Level2, Level3, Level4)</label>
            <InputFile OnChange="LoadFile" accept=".csv" class="form-input" />
        </div>
    }
    else
    {
        <div class="form-group">
            <label class="form-label">Folder Structure</label>
            <div class="folder-builder">
                @foreach (var root in _tree)
                {
                    <FolderTreeNode Node="root" Depth="1" OnRemove="RemoveRoot" OnChanged="RebuildFromTree" />
                }
                @if (_tree.Count == 0)
                {
                    <p class="text-muted">No folders yet. Add a top-level folder to start.</p>
                }
            </div>
            <button class="btn btn-secondary btn-sm mt-8" type="button" @onclick="AddRoot">+ Add top-level folder</button>
        </div>
    }

    @if (_rows.Count > 0)
    {
        <div class="alert alert-info mt-8">@_rows.Count(r => r.IsValid) valid rows, @_rows.Count(r => !r.IsValid) errors.</div>
    }

    <div class="flex-row mt-8">
        <button class="btn btn-primary" @onclick="RunCreate" disabled="@(_running || _rows.Count == 0 || string.IsNullOrWhiteSpace(_libraryTitle))">
            @(_running ? "Creating…" : "Create Folders")
        </button>
        @if (_running) { <button class="btn btn-secondary" @onclick="Cancel">Cancel</button> }
    </div>
    <ProgressPanel IsRunning="_running" StatusMessage="@_status" Current="_current" Total="_total" />
</div>

@if (!string.IsNullOrEmpty(_error)) { <div class="alert alert-error">@_error</div> }

@if (_summary != null)
{
    <div class="card">
        <div class="alert @(_summary.HasFailures ? "alert-warn" : "alert-success")">
            Created: @_summary.SuccessCount folders. Failures: @_summary.FailedCount
        </div>
    </div>
}

@code {
    private enum InputMode { Csv, Builder }
    private InputMode _mode = InputMode.Csv;

    private List<SiteInfo> _sites = new();
    private string _libraryTitle = string.Empty;
    private List<CsvValidationRow<FolderStructureRow>> _rows = new();
    private readonly List<FolderNode> _tree = new();
    private bool _running; private string _status = string.Empty, _error = string.Empty;
    private int _current, _total;
    private BulkOperationSummary<string>? _summary;
    private CancellationTokenSource? _cts;

    private void SetMode(InputMode mode)
    {
        _mode = mode;
        _rows.Clear();
        _summary = null; _error = string.Empty;
        if (mode == InputMode.Builder) RebuildFromTree();
    }

    private async Task LoadFile(InputFileChangeEventArgs e)
    {
        _rows.Clear();
        using var stream = e.File.OpenReadStream(maxAllowedSize: 5 * 1024 * 1024);
        _rows = CsvValidation.ParseAndValidateFolders(stream);
    }

    private void AddRoot()
    {
        _tree.Add(new FolderNode());
        RebuildFromTree();
    }

    private void RemoveRoot(FolderNode node)
    {
        _tree.Remove(node);
        RebuildFromTree();
    }

    // Convert the visual tree into validation rows so the count + Create button share the CSV path.
    private void RebuildFromTree()
    {
        _rows = FolderNode.Flatten(_tree)
            .Select(r => new CsvValidationRow<FolderStructureRow>(r, new List<string>()))
            .ToList();
    }

    private async Task RunCreate()
    {
        _error = string.Empty; _summary = null; _running = true;
        _cts = new CancellationTokenSource();
        var validRows = _rows.Where(r => r.IsValid && r.Record != null).Select(r => r.Record!).ToList();
        var siteUrl = _sites.FirstOrDefault()?.Url;
        if (string.IsNullOrWhiteSpace(siteUrl)) { _error = "Please select a site."; _running = false; return; }
        var progress = new Progress<OperationProgress>(p => { _status = p.Message; _current = p.Current; _total = p.Total; InvokeAsync(StateHasChanged); });
        try
        {
            _summary = await Elevation.RunAsync(async c =>
            {
                var ctx = await SessionMgr.GetOrCreateContextAsync(siteUrl, Session.CurrentProfile!, c);
                return await FolderSvc.CreateFoldersAsync(ctx, _libraryTitle, validRows, progress, c);
            }, _cts.Token);
            _status = $"Complete: {_summary.SuccessCount} folders created.";
        }
        catch (OperationCanceledException) { _status = "Cancelled."; }
        catch (Exception ex) { _error = ex.Message; }
        finally { _running = false; await InvokeAsync(StateHasChanged); }
    }

    private void Cancel() => _cts?.Cancel();
}