using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Globalization;
using System.Linq;
using Avalonia.Input;
using Avalonia.Input.Platform;
using Avalonia.Interactivity;
using Avalonia.Styling;

namespace Avalonia.Controls
{
    public class MaskedTextBox : TextBox, IStyleable
    {
        public static readonly StyledProperty<bool> AsciiOnlyProperty =
             AvaloniaProperty.Register<MaskedTextBox, bool>(nameof(AsciiOnly));

        public static readonly DirectProperty<MaskedTextBox, CultureInfo?> CultureProperty =
             AvaloniaProperty.RegisterDirect<MaskedTextBox, CultureInfo?>(nameof(Culture), o => o.Culture,
                (o, v) => o.Culture = v, CultureInfo.CurrentCulture);

        public static readonly StyledProperty<bool> HidePromptOnLeaveProperty =
             AvaloniaProperty.Register<MaskedTextBox, bool>(nameof(HidePromptOnLeave));

        public static readonly DirectProperty<MaskedTextBox, bool?> MaskCompletedProperty =
             AvaloniaProperty.RegisterDirect<MaskedTextBox, bool?>(nameof(MaskCompleted), o => o.MaskCompleted);

        public static readonly DirectProperty<MaskedTextBox, bool?> MaskFullProperty =
             AvaloniaProperty.RegisterDirect<MaskedTextBox, bool?>(nameof(MaskFull), o => o.MaskFull);

        public static readonly StyledProperty<string?> MaskProperty =
             AvaloniaProperty.Register<MaskedTextBox, string?>(nameof(Mask), string.Empty);

        public static new readonly StyledProperty<char> PasswordCharProperty =
             AvaloniaProperty.Register<TextBox, char>(nameof(PasswordChar), '\0');

        public static readonly StyledProperty<char> PromptCharProperty =
             AvaloniaProperty.Register<MaskedTextBox, char>(nameof(PromptChar), '_');

        public static readonly DirectProperty<MaskedTextBox, bool> ResetOnPromptProperty =
             AvaloniaProperty.RegisterDirect<MaskedTextBox, bool>(nameof(ResetOnPrompt), o => o.ResetOnPrompt, (o, v) => o.ResetOnPrompt = v);

        public static readonly DirectProperty<MaskedTextBox, bool> ResetOnSpaceProperty =
             AvaloniaProperty.RegisterDirect<MaskedTextBox, bool>(nameof(ResetOnSpace), o => o.ResetOnSpace, (o, v) => o.ResetOnSpace = v);

        private CultureInfo? _culture;

        private bool _resetOnPrompt = true;

        private bool _ignoreTextChanges;

        private bool _resetOnSpace = true;

        public MaskedTextBox() { }

        /// <summary>
        ///  Constructs the MaskedTextBox with the specified MaskedTextProvider object.
        /// </summary>
        public MaskedTextBox(MaskedTextProvider maskedTextProvider)
        {
            if (maskedTextProvider == null)
            {
                throw new ArgumentNullException(nameof(maskedTextProvider));
            }
            AsciiOnly = maskedTextProvider.AsciiOnly;
            Culture = maskedTextProvider.Culture;
            Mask = maskedTextProvider.Mask;
            PasswordChar = maskedTextProvider.PasswordChar;
            PromptChar = maskedTextProvider.PromptChar;
        }

        /// <summary>
        /// Gets or sets a value indicating if the masked text box is restricted to accept only ASCII characters.
        /// Default value is false.
        /// </summary>
        public bool AsciiOnly
        {
            get => GetValue(AsciiOnlyProperty);
            set => SetValue(AsciiOnlyProperty, value);
        }

        /// <summary>
        /// Gets or sets the culture information associated with the masked text box.
        /// </summary>
        public CultureInfo? Culture
        {
            get => _culture;
            set => SetAndRaise(CultureProperty, ref _culture, value);
        }

        /// <summary>
        /// Gets or sets a value indicating if the prompt character is hidden when the masked text box loses focus.
        /// </summary>
        public bool HidePromptOnLeave
        {
            get => GetValue(HidePromptOnLeaveProperty);
            set => SetValue(HidePromptOnLeaveProperty, value);
        }

        /// <summary>
        /// Gets or sets the mask to apply to the TextBox.
        /// </summary>
        public string? Mask
        {
            get => GetValue(MaskProperty);
            set => SetValue(MaskProperty, value);
        }

        /// <summary>
        ///  Specifies whether the test string required input positions, as specified by the mask, have
        ///  all been assigned.
        /// </summary>
        public bool? MaskCompleted
        {
            get => MaskProvider?.MaskCompleted;
        }

        /// <summary>
        ///  Specifies whether all inputs (required and optional) have been provided into the mask successfully.
        /// </summary>
        public bool? MaskFull
        {
            get => MaskProvider?.MaskFull;
        }

        /// <summary>
        /// Gets the MaskTextProvider for the specified Mask.
        /// </summary>
        public MaskedTextProvider? MaskProvider { get; private set; }

        /// <summary>
        /// Gets or sets the character to be displayed in substitute for user input.
        /// </summary>
        public new char PasswordChar
        {
            get => GetValue(PasswordCharProperty);
            set => SetValue(PasswordCharProperty, value);
        }

        /// <summary>
        /// Gets or sets the character used to represent the absence of user input in MaskedTextBox.
        /// </summary>
        public char PromptChar
        {
            get => GetValue(PromptCharProperty);
            set => SetValue(PromptCharProperty, value);
        }

        /// <summary>
        /// Gets or sets a value indicating if selected characters should be reset when the prompt character is pressed.
        /// </summary>
        public bool ResetOnPrompt
        {
            get => _resetOnPrompt;
            set
            {
                SetAndRaise(ResetOnPromptProperty, ref _resetOnPrompt, value);
                if (MaskProvider != null)
                {
                    MaskProvider.ResetOnPrompt = value;
                }

            }
        }

        /// <summary>
        /// Gets or sets a value indicating if selected characters should be reset when the space character is pressed.
        /// </summary>
        public bool ResetOnSpace
        {
            get => _resetOnSpace;
            set
            {
                SetAndRaise(ResetOnSpaceProperty, ref _resetOnSpace, value);
                if (MaskProvider != null)
                {
                    MaskProvider.ResetOnSpace = value;
                }

            }


        }

        Type IStyleable.StyleKey => typeof(TextBox);

        protected override void OnGotFocus(GotFocusEventArgs e)
        {
            if (HidePromptOnLeave == true && MaskProvider != null)
            {
                Text = MaskProvider.ToDisplayString();
            }
            base.OnGotFocus(e);
        }

        protected override async void OnKeyDown(KeyEventArgs e)
        {
            if (MaskProvider == null)
            {
                base.OnKeyDown(e);
                return;
            }

            var keymap = AvaloniaLocator.Current.GetService<PlatformHotkeyConfiguration>();

            bool Match(List<KeyGesture> gestures) => gestures.Any(g => g.Matches(e));

            if (keymap is not null && Match(keymap.Paste))
            {
                var clipboard = (IClipboard?)AvaloniaLocator.Current.GetService(typeof(IClipboard));

                if (clipboard is null)
                    return;

                var text = await clipboard.GetTextAsync();

                if (text == null)
                    return;

                foreach (var item in text)
                {
                    var index = GetNextCharacterPosition(CaretIndex);
                    if (MaskProvider.InsertAt(item, index))
                    {
                        CaretIndex = ++index;
                    }
                }

                Text = MaskProvider.ToDisplayString();
                e.Handled = true;
                return;
            }

            if (e.Key != Key.Back)
            {
                base.OnKeyDown(e);
            }

            switch (e.Key)
            {
                case Key.Delete:
                    if (CaretIndex < Text?.Length)
                    {
                        if (MaskProvider.RemoveAt(CaretIndex))
                        {
                            RefreshText(MaskProvider, CaretIndex);
                        }

                        e.Handled = true;
                    }
                    break;
                case Key.Space:
                    if (!MaskProvider.ResetOnSpace || string.IsNullOrEmpty(SelectedText))
                    {
                        if (MaskProvider.InsertAt(" ", CaretIndex))
                        {
                            RefreshText(MaskProvider, CaretIndex);
                        }
                    }

                    e.Handled = true;
                    break;
                case Key.Back:
                    if (CaretIndex > 0)
                    {
                        MaskProvider.RemoveAt(CaretIndex - 1);
                    }
                    RefreshText(MaskProvider, CaretIndex - 1);
                    e.Handled = true;
                    break;
            }
        }

        protected override void OnLostFocus(RoutedEventArgs e)
        {
            if (HidePromptOnLeave == true && MaskProvider != null)
            {
                Text = MaskProvider.ToString(!HidePromptOnLeave, true);
            }
            base.OnLostFocus(e);
        }

        protected override void OnPropertyChanged<T>(AvaloniaPropertyChangedEventArgs<T> change)
        {
            void UpdateMaskProvider()
            {
                MaskProvider = new MaskedTextProvider(Mask!, Culture, true, PromptChar, PasswordChar, AsciiOnly) { ResetOnSpace = ResetOnSpace, ResetOnPrompt = ResetOnPrompt };
                if (Text != null)
                {
                    MaskProvider.Set(Text);
                }
                RefreshText(MaskProvider, 0);
            }
            if (change.Property == TextProperty && MaskProvider != null && _ignoreTextChanges == false)
            {
                if (string.IsNullOrEmpty(Text))
                {
                    MaskProvider.Clear();
                    RefreshText(MaskProvider, CaretIndex);
                    base.OnPropertyChanged(change);
                    return;
                }

                MaskProvider.Set(Text);
                RefreshText(MaskProvider, CaretIndex);
            }
            else if (change.Property == MaskProperty)
            {
                UpdateMaskProvider();

                if (!string.IsNullOrEmpty(Mask))
                {
                    foreach (var c in Mask!)
                    {
                        if (!MaskedTextProvider.IsValidMaskChar(c))
                        {
                            throw new ArgumentException("Specified mask contains characters that are not valid.");
                        }
                    }
                }
            }
            else if (change.Property == PasswordCharProperty)
            {
                if (!MaskedTextProvider.IsValidPasswordChar(PasswordChar))
                {
                    throw new ArgumentException("Specified character value is not allowed for this property.", nameof(PasswordChar));
                }
                if (MaskProvider != null && PasswordChar == MaskProvider.PromptChar)
                {
                    // Prompt and password chars must be different.
                    throw new InvalidOperationException("PasswordChar and PromptChar values cannot be the same.");
                }
                if (MaskProvider != null && MaskProvider.PasswordChar != PasswordChar)
                {
                    UpdateMaskProvider();
                }
            }
            else if (change.Property == PromptCharProperty)
            {
                if (!MaskedTextProvider.IsValidInputChar(PromptChar))
                {
                    throw new ArgumentException("Specified character value is not allowed for this property.");
                }
                if (PromptChar == PasswordChar)
                {
                    throw new InvalidOperationException("PasswordChar and PromptChar values cannot be the same.");
                }
                if (MaskProvider != null && MaskProvider.PromptChar != PromptChar)
                {
                    UpdateMaskProvider();
                }
            }
            else if (change.Property == AsciiOnlyProperty && MaskProvider != null && MaskProvider.AsciiOnly != AsciiOnly
                 || change.Property == CultureProperty && MaskProvider != null && !MaskProvider.Culture.Equals(Culture))
            {
                UpdateMaskProvider();
            }
            base.OnPropertyChanged(change);
        }
        protected override void OnTextInput(TextInputEventArgs e)
        {
            _ignoreTextChanges = true;
            try
            {
                if (IsReadOnly)
                {
                    e.Handled = true;
                    base.OnTextInput(e);
                    return;
                }
                if (MaskProvider == null)
                {
                    base.OnTextInput(e);
                    return;
                }
                if ((MaskProvider.ResetOnSpace && e.Text == " " || MaskProvider.ResetOnPrompt && e.Text == MaskProvider.PromptChar.ToString()) && !string.IsNullOrEmpty(SelectedText))
                {
                    if (SelectionStart > SelectionEnd ? MaskProvider.RemoveAt(SelectionEnd, SelectionStart - 1) : MaskProvider.RemoveAt(SelectionStart, SelectionEnd - 1))
                    {
                        SelectedText = string.Empty;
                    }
                }

                if (CaretIndex < Text?.Length)
                {
                    CaretIndex = GetNextCharacterPosition(CaretIndex);

                    if (MaskProvider.InsertAt(e.Text!, CaretIndex))
                    {
                        CaretIndex++;
                    }
                    var nextPos = GetNextCharacterPosition(CaretIndex);
                    if (nextPos != 0 && CaretIndex != Text.Length)
                    {
                        CaretIndex = nextPos;
                    }
                }

                RefreshText(MaskProvider, CaretIndex);


                e.Handled = true;

                base.OnTextInput(e);
            }
            finally
            {
                _ignoreTextChanges = false;
            }

        }

        private int GetNextCharacterPosition(int startPosition)
        {
            if (MaskProvider != null)
            {
                var position = MaskProvider.FindEditPositionFrom(startPosition, true);
                if (CaretIndex != -1)
                {
                    return position;
                }
            }
            return startPosition;
        }

        private void RefreshText(MaskedTextProvider provider, int position)
        {
            if (provider != null)
            {
                Text = provider.ToDisplayString();
                CaretIndex = position;
            }
        }

    }
}