// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using System;
using System.Collections.Immutable;
using System.ComponentModel;
using System.Linq;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.LanguageService;
using Microsoft.VisualStudio.Imaging;
using Microsoft.VisualStudio.Imaging.Interop;
using Microsoft.VisualStudio.LanguageServices.Implementation.Utilities;
 
namespace Microsoft.VisualStudio.LanguageServices.Implementation.MoveStaticMembers;
 
internal class MoveStaticMembersDialogViewModel : AbstractNotifyPropertyChanged
{
    public StaticMemberSelectionViewModel MemberSelectionViewModel { get; }
 
    private readonly ISyntaxFacts _syntaxFacts;
 
    public MoveStaticMembersDialogViewModel(
        StaticMemberSelectionViewModel memberSelectionViewModel,
        string defaultType,
        ImmutableArray<TypeNameItem> availableTypes,
        string prependedNamespace,
        ISyntaxFacts syntaxFacts)
    {
        MemberSelectionViewModel = memberSelectionViewModel;
        _syntaxFacts = syntaxFacts ?? throw new ArgumentNullException(nameof(syntaxFacts));
        _searchText = defaultType;
        _destinationName = new TypeNameItem(defaultType);
        AvailableTypes = availableTypes;
        PrependedNamespace = string.IsNullOrEmpty(prependedNamespace) ? prependedNamespace : prependedNamespace + ".";
 
        PropertyChanged += MoveMembersToTypeDialogViewModel_PropertyChanged;
        OnDestinationUpdated();
    }
 
    private void MoveMembersToTypeDialogViewModel_PropertyChanged(object sender, PropertyChangedEventArgs e)
    {
        switch (e.PropertyName)
        {
            case nameof(DestinationName):
                OnDestinationUpdated();
                break;
 
            case nameof(SearchText):
                OnSearchTextUpdated();
                break;
        }
    }
 
    private void OnSearchTextUpdated()
    {
        var foundItem = AvailableTypes.FirstOrDefault(t => t.TypeName == SearchText);
        if (foundItem is null)
        {
            DestinationName = new(PrependedNamespace + SearchText);
            return;
        }
 
        DestinationName = foundItem;
    }
 
    public void OnDestinationUpdated()
    {
        if (!_destinationName.IsNew)
        {
            CanSubmit = true;
            ShowMessage = false;
            return;
        }
 
        CanSubmit = IsValidType(_destinationName.TypeName);
 
        if (CanSubmit)
        {
            Icon = KnownMonikers.StatusInformation;
            Message = ServicesVSResources.New_Type_Name_colon;
            ShowMessage = true;
        }
        else
        {
            Icon = KnownMonikers.StatusInvalid;
            Message = ServicesVSResources.Invalid_type_name;
            ShowMessage = true;
        }
    }
 
    private bool IsValidType(string typeName)
    {
        if (string.IsNullOrEmpty(typeName))
        {
            return false;
        }
 
        foreach (var identifier in typeName.Split('.'))
        {
            if (_syntaxFacts.IsValidIdentifier(identifier))
            {
                continue;
            }
 
            return false;
        }
 
        return true;
    }
 
    public string PrependedNamespace { get; }
    public ImmutableArray<TypeNameItem> AvailableTypes { get; }
 
    private TypeNameItem _destinationName;
    public TypeNameItem DestinationName
    {
        get => _destinationName;
        private set => SetProperty(ref _destinationName, value);
    }
 
    private ImageMoniker _icon;
    public ImageMoniker Icon
    {
        get => _icon;
        private set => SetProperty(ref _icon, value);
    }
 
    private string? _message;
    public string? Message
    {
        get => _message;
        private set => SetProperty(ref _message, value);
    }
 
    private bool _showMessage = false;
    public bool ShowMessage
    {
        get => _showMessage;
        private set => SetProperty(ref _showMessage, value);
    }
 
    private bool _canSubmit = true;
    public bool CanSubmit
    {
        get => _canSubmit;
        set => SetProperty(ref _canSubmit, value);
    }
 
    private string _searchText;
    public string SearchText
    {
        get => _searchText;
        set => SetProperty(ref _searchText, value);
    }
}