DbFirst/DbFirst.BlazorWasm/Pages/Catalogs.razor

@* Stellt die Catalog-Verwaltung bereit.
   Nutzt CatalogApiClient für API-Interaktionen und DevExpress-Komponenten für die Benutzeroberfläche. *@

@page "/catalogs"
@inject CatalogApiClient Api

<style>
    .action-panel { margin-bottom: 16px; }
    .grid-section { margin-top: 12px; }
</style>

<PageTitle>Catalogs</PageTitle>

<h1>Catalogs</h1>

@if (!string.IsNullOrWhiteSpace(errorMessage))
{
    <div class="alert alert-danger" role="alert">@errorMessage</div>
}
else if (!string.IsNullOrWhiteSpace(infoMessage))
{
    <div class="alert alert-success" role="alert">@infoMessage</div>
}

<div class="mb-3">
    <DxButton RenderStyle="ButtonRenderStyle.Primary" Click="@StartCreate">Neuen Eintrag anlegen</DxButton>
</div>

@if (showForm)
{
    <div class="action-panel">
        <EditForm Model="formModel" OnValidSubmit="HandleSubmit" Context="editCtx">
            <DxFormLayout ColCount="2">
                <DxFormLayoutItem Caption="Titel" Context="itemCtx">
                    <DxTextBox @bind-Text="formModel.CatTitle" Enabled="@(isEditing ? formModel.UpdateProcedure != 0 : true)" />
                </DxFormLayoutItem>
                <DxFormLayoutItem Caption="Kennung" Context="itemCtx">
                    <DxTextBox @bind-Text="formModel.CatString" />
                </DxFormLayoutItem>
                @if (isEditing)
                {
                    <DxFormLayoutItem Caption="Update-Prozedur" Context="itemCtx">
                        <DxComboBox Data="@procedureOptions"
                                    TextFieldName="Text"
                                    ValueFieldName="Value"
                                    @bind-Value="formModel.UpdateProcedure" />
                    </DxFormLayoutItem>
                }
                <DxFormLayoutItem Caption=" " Context="itemCtx">
                    <DxStack Orientation="Orientation.Horizontal" Spacing="8">
                        <DxButton RenderStyle="ButtonRenderStyle.Success" ButtonType="ButtonType.Submit" SubmitFormOnClick="true" Context="btnCtx">@((isEditing ? "Speichern" : "Anlegen"))</DxButton>
                        <DxButton RenderStyle="ButtonRenderStyle.Secondary" Click="@CancelEdit" Context="btnCtx">Abbrechen</DxButton>
                    </DxStack>
                </DxFormLayoutItem>
            </DxFormLayout>
        </EditForm>
    </div>
}

@if (isLoading)
{
    <p><em>Lade Daten...</em></p>
}
else if (items.Count == 0)
{
    <p>Keine Einträge vorhanden.</p>
}
else
{
    <div class="grid-section">
        <DxGrid Data="@items" TItem="CatalogReadDto" KeyFieldName="@nameof(CatalogReadDto.Guid)" ShowFilterRow="true" PageSize="10" CssClass="mb-4">
            <Columns>
                <DxGridDataColumn FieldName="@nameof(CatalogReadDto.Guid)" Caption="Id" Width="140px" />
                <DxGridDataColumn FieldName="@nameof(CatalogReadDto.CatTitle)" Caption="Titel" />
                <DxGridDataColumn FieldName="@nameof(CatalogReadDto.CatString)" Caption="String" />
                <DxGridDataColumn FieldName="@nameof(CatalogReadDto.AddedWho)" Caption="Angelegt von" />
                <DxGridDataColumn FieldName="@nameof(CatalogReadDto.AddedWhen)" Caption="Angelegt am" />
                <DxGridDataColumn FieldName="@nameof(CatalogReadDto.ChangedWho)" Caption="Geändert von" />
                <DxGridDataColumn FieldName="@nameof(CatalogReadDto.ChangedWhen)" Caption="Geändert am" />
                <DxGridDataColumn Caption="" Width="220px">
                    <CellDisplayTemplate Context="cell">
                        @{ var item = (CatalogReadDto)cell.DataItem; }
                        <div style="white-space: nowrap;">
                            <DxButton RenderStyle="ButtonRenderStyle.Secondary" Size="ButtonSize.Small" Click="@(() => StartEdit(item))">Bearbeiten</DxButton>
                            <DxButton RenderStyle="ButtonRenderStyle.Danger" Size="ButtonSize.Small" Click="@(() => DeleteCatalog(item.Guid))">Löschen</DxButton>
                        </div>
                    </CellDisplayTemplate>
                </DxGridDataColumn>
            </Columns>
        </DxGrid>
    </div>
}

@code {
    private List<CatalogReadDto> items = new();
    private CatalogWriteDto formModel = new();
    private int editingId;
    private bool isLoading;
    private bool isEditing;
    private bool showForm;
    private string? errorMessage;
    private string? infoMessage;

    private readonly List<ProcedureOption> procedureOptions = new()
    {
        new() { Value = 0, Text = "PRTBMY_CATALOG_UPDATE" },
        new() { Value = 1, Text = "PRTBMY_CATALOG_SAVE" }
    };

    protected override async Task OnInitializedAsync()
    {
        await LoadCatalogs();
    }

    private async Task LoadCatalogs()
    {
        // Lädt die Liste der Kataloge aus der API.
        // Setzt Ladezustand und behandelt Fehler.

        isLoading = true;
        errorMessage = null;
        try
        {
            items = await Api.GetAllAsync();
        }
        catch (Exception ex)
        {
            errorMessage = $"Kataloge konnten nicht geladen werden: {ex.Message}";
        }
        finally
        {
            isLoading = false;
            StateHasChanged();
        }
    }

    private void StartCreate()
    {
        formModel = new CatalogWriteDto();
        editingId = 0;
        isEditing = false;
        showForm = true;
        infoMessage = null;
        errorMessage = null;
    }

    private void StartEdit(CatalogReadDto item)
    {
        formModel = new CatalogWriteDto
        {
            CatTitle = item.CatTitle,
            CatString = item.CatString,
            UpdateProcedure = 0
        };
        editingId = item.Guid;
        isEditing = true;
        showForm = true;
        infoMessage = null;
        errorMessage = null;
    }

    private async Task HandleSubmit()
    {
        // Behandelt das Absenden des Formulars.
        // Führt entweder eine Aktualisierung oder das Anlegen eines neuen Eintrags durch.

        errorMessage = null;
        infoMessage = null;

        try
        {
            if (isEditing)
            {
                var updated = await Api.UpdateAsync(editingId, formModel);
                if (!updated.Success)
                {
                    errorMessage = updated.Error ?? "Aktualisierung fehlgeschlagen.";
                    return;
                }

                infoMessage = "Katalog aktualisiert.";
            }
            else
            {
                var created = await Api.CreateAsync(formModel);
                if (!created.Success || created.Value == null)
                {
                    errorMessage = created.Error ?? "Anlegen fehlgeschlagen.";
                    return;
                }

                infoMessage = "Katalog angelegt.";
            }

            showForm = false;
            await LoadCatalogs();
        }
        catch (Exception ex)
        {
            errorMessage = $"Fehler beim Speichern: {ex.Message}";
        }
    }

    private void CancelEdit()
    {
        showForm = false;
        infoMessage = null;
        errorMessage = null;
    }

    private async Task DeleteCatalog(int id)
    {
        // Löscht einen Katalogeintrag basierend auf der ID.
        // Aktualisiert die Liste nach erfolgreichem Löschen.

        errorMessage = null;
        infoMessage = null;

        try
        {
            var deleted = await Api.DeleteAsync(id);
            if (!deleted.Success)
            {
                errorMessage = deleted.Error ?? "Löschen fehlgeschlagen.";
                return;
            }

            infoMessage = "Katalog gelöscht.";
            await LoadCatalogs();
        }
        catch (Exception ex)
        {
            errorMessage = $"Fehler beim Löschen: {ex.Message}";
        }
    }

    private sealed class ProcedureOption
    {
        public int Value { get; set; }
        public string Text { get; set; } = string.Empty;
    }
}