using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace Tango.Touch.Controls
{
    public class TouchNumericTextBox : TouchInput, IValueControl
    {
        private TextBox _text_box;
        private bool _prevent_text_change;
        private TextBlock _text_block;
        private double _lastValue;
        Regex regex_integer = new Regex(@"^[0-9]*(?:[0-9]*)?$");
        Regex regex_double = new Regex(@"^[0-9]*(?:\.[0-9]*)?$");

        public static readonly RoutedEvent ValueChangedEvent = EventManager.RegisterRoutedEvent("ValueChanged", RoutingStrategy.Bubble, typeof(DoubleValueChangedEventHandler), typeof(TouchNumericTextBox));
        public event DoubleValueChangedEventHandler ValueChanged
        {
            add { AddHandler(ValueChangedEvent, value); }
            remove { RemoveHandler(ValueChangedEvent, value); }
        }

        public double Value
        {
            get { return (double)GetValue(ValueProperty); }
            set { SetValue(ValueProperty, value); }
        }
        public static readonly DependencyProperty ValueProperty =
            DependencyProperty.Register("Value", typeof(double), typeof(TouchNumericTextBox), new FrameworkPropertyMetadata(0.0, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, (d, e) => (d as TouchNumericTextBox).OnValueChanged(), (d, e) => (d as TouchNumericTextBox).CoerceValue(d, e), false, UpdateSourceTrigger.Explicit));

        public String Watermark
        {
            get { return (String)GetValue(WatermarkProperty); }
            set { SetValue(WatermarkProperty, value); }
        }
        public static readonly DependencyProperty WatermarkProperty =
            DependencyProperty.Register("Watermark", typeof(String), typeof(TouchNumericTextBox), new PropertyMetadata(null));

        public String StringFormat
        {
            get { return (String)GetValue(StringFormatProperty); }
            set { SetValue(StringFormatProperty, value); }
        }
        public static readonly DependencyProperty StringFormatProperty =
            DependencyProperty.Register("StringFormat", typeof(String), typeof(TouchNumericTextBox), new PropertyMetadata(null));

        public bool HasDecimalPoint
        {
            get { return (bool)GetValue(HasDecimalPointProperty); }
            set { SetValue(HasDecimalPointProperty, value); }
        }
        public static readonly DependencyProperty HasDecimalPointProperty =
            DependencyProperty.Register("HasDecimalPoint", typeof(bool), typeof(TouchNumericTextBox), new PropertyMetadata(false));

        public double Minimum
        {
            get { return (double)GetValue(MinimumProperty); }
            set { SetValue(MinimumProperty, value); }
        }
        public static readonly DependencyProperty MinimumProperty =
            DependencyProperty.Register("Minimum", typeof(double), typeof(TouchNumericTextBox), new PropertyMetadata(0.0));

        public double Maximum
        {
            get { return (double)GetValue(MaximumProperty); }
            set { SetValue(MaximumProperty, value); }
        }
        public static readonly DependencyProperty MaximumProperty =
            DependencyProperty.Register("Maximum", typeof(double), typeof(TouchNumericTextBox), new PropertyMetadata(100.0));

        public double JoggingFactor
        {
            get { return (double)GetValue(JoggingFactorProperty); }
            set { SetValue(JoggingFactorProperty, value); }
        }
        public static readonly DependencyProperty JoggingFactorProperty =
            DependencyProperty.Register("JoggingFactor", typeof(double), typeof(TouchNumericTextBox), new PropertyMetadata(1.0));

        public bool AutoCalculateJogStep
        {
            get { return (bool)GetValue(AutoCalculateJogStepProperty); }
            set { SetValue(AutoCalculateJogStepProperty, value); }
        }
        public static readonly DependencyProperty AutoCalculateJogStepProperty =
            DependencyProperty.Register("AutoCalculateJogStep", typeof(bool), typeof(TouchNumericTextBox), new PropertyMetadata(true));

        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();

            _text_box = GetTemplateChild("PART_TextBox") as TextBox;
            _text_block = GetTemplateChild("PART_TextDisplay") as TextBlock;
            _text_box.PreviewTextInput += _text_box_PreviewTextInput;
            _text_box.PreviewKeyDown += _text_box_PreviewKeyDown;
            _text_box.LostFocus += _text_box_LostFocus;
            _text_box.GotFocus += _text_box_GotFocus;
            _text_box.TextChanged += _text_box_TextChanged;

            Value = Value;

            OnValueChanged();
        }

        private async void _text_box_GotFocus(object sender, RoutedEventArgs e)
        {
            await Task.Delay(50);

            if (FocusSelectionMode == FocusSelectionMode.SelectAll)
            {
                _text_box.SelectAll();
            }
            else if (FocusSelectionMode == FocusSelectionMode.ScrollToEnd)
            {
                _text_box.CaretIndex = _text_box.Text.Length;
            }
        }

        private object CoerceValue(DependencyObject d, object e)
        {
            double value = (double)e;

            if (_text_box != null) //Min and max not being set yet...
            {
                if (!HasDecimalPoint)
                {
                    value = Math.Round(value, 0);
                }

                if (value < Minimum)
                {
                    value = Minimum;
                }
                else if (value > Maximum)
                {
                    value = Maximum;
                }
            }

            return value;
        }

        private void _text_box_LostFocus(object sender, RoutedEventArgs e)
        {
            double d = 0.0;

            if (double.TryParse(_text_box.Text, out d))
            {
                Value = d;
                _text_box.Text = Value.ToString();
            }

            _text_block.Text = Value.ToString(StringFormat);
        }

        private void _text_box_PreviewKeyDown(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Space)
            {
                e.Handled = true;
            }
        }

        private void OnValueChanged()
        {
            if (_text_box != null && !_prevent_text_change)
            {
                if (StringFormat != null)
                {
                    _text_box.Text = Value.ToString(StringFormat);
                }
                else
                {
                    _text_box.Text = Value.ToString();
                }

                _text_block.Text = _text_box.Text;
            }

            if (Value != _lastValue)
            {
                BindingExpression b = GetBindingExpression(ValueProperty);

                if (b != null)
                {
                    b.UpdateSource();
                }

                _lastValue = Value;

                DoubleValueChangedEventArgs args = new DoubleValueChangedEventArgs(ValueChangedEvent, this, Value);
                RaiseEvent(args);
            }
        }

        private void _text_box_PreviewTextInput(object sender, TextCompositionEventArgs e)
        {
            if (e.Text == "." && _text_box.Text.Contains('.'))
            {
                e.Handled = true;
                return;
            }

            if (HasDecimalPoint)
            {
                e.Handled = !regex_double.IsMatch(e.Text);
            }
            else
            {
                e.Handled = !regex_integer.IsMatch(e.Text);
            }
        }

        private void _text_box_TextChanged(object sender, TextChangedEventArgs e)
        {
            double d = 0.0;

            if (double.TryParse(_text_box.Text, out d))
            {
                _prevent_text_change = true;
                Value = d;
                _prevent_text_change = false;
            }
        }

        static TouchNumericTextBox()
        {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(TouchNumericTextBox), new FrameworkPropertyMetadata(typeof(TouchNumericTextBox)));
        }
    }
}