using System;
using System.Globalization;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Data;

namespace LiveCharts.Uwp.Components.MultiBinding
{
    /// <summary>
    /// An <see cref="IValueConverter"/> abstract implementation to be used with the <see cref="MultiBindingBehavior"/>.
    /// </summary>
    public abstract class MultiValueConverterBase : DependencyObject, IValueConverter
    {
        /// <summary>
        /// Modifies the source data before passing it to the target for display in the UI.
        /// </summary>
        /// <returns>The value to be passed to the target dependency property.</returns>
        /// <param name="values">The source data being passed to the target.</param>
        /// <param name="targetType">The <see cref="T:System.Type"/> of data expected by the target dependency property.</param>
        /// <param name="parameter">An optional parameter to be used in the converter logic.</param>
        /// <param name="culture">The culture of the conversion.</param>
        public abstract object Convert(object[] values, Type targetType, object parameter, CultureInfo culture);

        /// <summary>
        /// Modifies the target data before passing it to the source object. This method is called only in <see cref="F:System.Windows.Data.BindingMode.TwoWay"/> bindings.
        /// </summary>
        /// <returns>The value to be passed to the source object.</returns>
        /// <param name="value">The target data being passed to the source.</param>
        /// <param name="targetType">The <see cref="T:System.Type"/> of data expected by the source object.</param>
        /// <param name="parameter">An optional parameter to be used in the converter logic.</param>
        /// <param name="culture">The culture of the conversion.</param>
        public abstract object[] ConvertBack(object value, Type targetType, object parameter, CultureInfo culture);

        object IValueConverter.Convert(object value, Type targetType, object parameter, string language)
        {
            var cultureInfo = !string.IsNullOrEmpty(language) ? new CultureInfo(language) : null;

            return Convert((object[])value, targetType, parameter, cultureInfo);
        }

        object IValueConverter.ConvertBack(object value, Type targetType, object parameter, string language)
        {
            var cultureInfo = !string.IsNullOrEmpty(language) ? new CultureInfo(language) : null;

            return ConvertBack(value, targetType, parameter, cultureInfo);
        }
    }
}