namespace Bsevita.Library.Ui.Pages;

public partial class Books
{
    [SupplyParameterFromQuery(Name = "focus")]
    public string? Focus { get; set; }

    private List<BookDto> _books = [];
    private string _searchText = string.Empty;
    private string _searchFilter = "title";
    private bool _isLoading = true;
    private bool _isSaving;
    private bool _showEditor;
    private Guid? _editingId;
    private SaveBookRequest _editModel = new();
    private BookDto? _bookToDelete;
    private string? _errorMessage;
    private string? _successMessage;

    private bool HasSearchText => !string.IsNullOrWhiteSpace(_searchText);
    private bool ShouldFocusSearch => string.Equals(Focus, "search", StringComparison.OrdinalIgnoreCase);
    private string EditorTitle => _editingId is null ? "Neu anlegen" : "Bearbeiten";
    private string SaveButtonText => _isSaving ? "Speichert ..." : "Speichern";
    private string DeleteMessage => _bookToDelete is null
        ? string.Empty
        : $"Soll '{_bookToDelete.Title}' wirklich gelöscht werden? Ausgeliehene Bücher können nicht gelöscht werden.";

    protected override Task OnInitializedAsync() => LoadAsync();

    private async Task LoadAsync()
    {
        _isLoading = true;
        try
        {
            _books = (await BooksApi.GetAllAsync()).ToList();
        }
        catch (Exception exception)
        {
            _errorMessage = Error(exception);
            _books = [];
        }
        finally
        {
            _isLoading = false;
        }
    }

    private async Task SearchAsync()
    {
        if (string.IsNullOrWhiteSpace(_searchText))
        {
            await LoadAsync();
            return;
        }

        _isLoading = true;
        try
        {
            var searchText = _searchText.Trim();
            if (_searchFilter == "number")
            {
                var book = await BooksApi.GetByNumberAsync(searchText);
                _books = [book];
            }
            else
            {
                _books = (await BooksApi.SearchAsync(_searchFilter, searchText)).ToList();
            }
        }
        catch (Exception exception)
        {
            _errorMessage = Error(exception);
            _books = [];
        }
        finally
        {
            _isLoading = false;
        }
    }

    private async Task ResetSearchAsync()
    {
        _searchText = string.Empty;
        await LoadAsync();
    }

    private async Task HandleSearchKey(KeyboardEventArgs args)
    {
        if (args.Key == "Enter")
        {
            await SearchAsync();
        }
    }

    private void OpenCreate()
    {
        _editingId = null;
        _editModel = new SaveBookRequest();
        _showEditor = true;
        ClearMessages();
    }

    private async Task OpenEditAsync(Guid id)
    {
        ClearMessages();
        try
        {
            var book = await BooksApi.GetByIdAsync(id);
            _editingId = book.Id;
            _editModel = new SaveBookRequest
            {
                BookNumber = book.BookNumber,
                Isbn = book.Isbn,
                Title = book.Title,
                Author = book.Author,
                Subject = book.Subject,
                Publisher = book.Publisher,
                PublicationYear = book.PublicationYear
            };
            _showEditor = true;
        }
        catch (Exception exception)
        {
            _errorMessage = Error(exception);
        }
    }

    private void CloseEditor()
    {
        if (!_isSaving)
        {
            _showEditor = false;
        }
    }

    private async Task SaveAsync()
    {
        _isSaving = true;
        try
        {
            if (_editingId is Guid id)
            {
                await BooksApi.UpdateAsync(id, _editModel);
            }
            else
            {
                await BooksApi.CreateAsync(_editModel);
            }

            _showEditor = false;
            _successMessage = _editingId is null ? "Buch wurde angelegt." : "Buch wurde gespeichert.";
            await LoadAsync();
        }
        catch (Exception exception)
        {
            _errorMessage = Error(exception);
        }
        finally
        {
            _isSaving = false;
        }
    }

    private void AskDelete(BookDto book) => _bookToDelete = book;

    private void CancelDelete() => _bookToDelete = null;

    private async Task DeleteAsync()
    {
        if (_bookToDelete is null)
        {
            return;
        }

        try
        {
            await BooksApi.DeleteBookAsync(_bookToDelete.Id);
            _successMessage = $"'{_bookToDelete.Title}' wurde gelöscht.";
            _bookToDelete = null;
            await LoadAsync();
        }
        catch (Exception exception)
        {
            _errorMessage = Error(exception);
            _bookToDelete = null;
        }
    }

    private void ClearMessages()
    {
        _errorMessage = null;
        _successMessage = null;
    }

    private static bool HasIsbn(BookDto book) => !string.IsNullOrWhiteSpace(book.Isbn);

    private static string Error(Exception exception) =>
        exception is ApiProblemException api ? api.Message : "Die Buchdaten konnten nicht verarbeitet werden.";
}