XmppFormViewModel.cs

using CommunityToolkit.Mvvm.ComponentModel;
using CommunityToolkit.Mvvm.Input;
using NeuroAccessMaui.Services;
using NeuroAccessMaui.UI.Pages.Main.XmppForm.Model;
using System.Collections.ObjectModel;
using Waher.Networking.XMPP.DataForms;
using Layout = Waher.Networking.XMPP.DataForms.Layout;
using Waher.Networking.XMPP.DataForms.FieldTypes;
 
namespace NeuroAccessMaui.UI.Pages.Main.XmppForm
{
    public partial class XmppFormViewModel : XmppViewModel
    {
        private readonly DataForm? form;
        private bool responseSent;
 
        public XmppFormViewModel(XmppFormNavigationArgs? Args)
            : base()
        {
            this.Pages = [];
 
            if (Args is not null)
            {
                this.form = Args.Form;
                this.responseSent = false;
 
                // TODO: Post-back fields.
 
                this.Title = this.form?.Title ?? string.Empty;
                this.Instructions = this.form?.Instructions ?? [];
 
                if (this.form?.HasPages ?? false)
                {
                    foreach (Layout.Page P in this.form.Pages)
                    {
                            this.Pages.Add(new PageModel(this, P));
                    }
                    this.MultiplePages = this.form.Pages.Length > 1;
                }
                else
                {
                    List<Layout.LayoutElement> Elements = [];
 
                    foreach (Field F in this.form?.Fields ?? [])
                    {
                        if (F is HiddenField)
                            continue;
 
                        Elements.Add(new Layout.FieldReference(this.form, F.Var));
                    }
 
                    this.Pages.Add(new PageModel(this, new Layout.Page(this.form, string.Empty, Elements.ToArray())));
 
                    this.MultiplePages = false;
                }
 
                this.ValidateForm();
            }
        }
 
        protected override async Task OnDispose()
        {
            if (this.form is not null && this.form.CanCancel && !this.responseSent)
            {
                this.form.Cancel();
                this.responseSent = true;
            }
 
            await base.OnDispose();
        }
 
        #region Properties
 
        [ObservableProperty]
        private string? title;
 
        [ObservableProperty]
        private string[]? instructions;
 
        public ObservableCollection<PageModel> Pages { get; }
 
        [ObservableProperty]
        private bool isFormOk;
 
        [ObservableProperty]
        private bool multiplePages;
 
        #endregion
 
        #region Commands
 
        [RelayCommand]
        private async Task Submit()
        {
            if (!this.IsFormOk)
                return;
 
            try
            {
                if (this.form is not null && this.form.CanSubmit && !this.responseSent)
                {
                    this.form.Submit();
                    this.responseSent = true;
 
                    await this.GoBack();
                }
            }
            catch (Exception ex)
            {
                await ServiceRef.UiService.DisplayException(ex);
            }
        }
 
        internal void ValidateForm()
        {
            try
            {
                foreach (Field F in this.form?.Fields ?? [])
                {
                    if (F.HasError)
                    {
                        this.IsFormOk = false;
                        return;
                    }
                }
 
                this.IsFormOk = true;
            }
            catch (Exception)
            {
                this.IsFormOk = false;
            }
        }
 
        #endregion
    }
}