using System.Collections.Generic;
using System.Linq;
using TINK.Model;
using TINK.Model.Connector;
using Xamarin.Forms;

namespace TINK.ViewModel.Map
{
    /// <remarks> Old name: MapPageFilter. </remarks>
    public class TinkKonradToggleViewModel : ITinkKonradToggleViewModel
    {
        /// <summary> Constructs a map page filter view model object from values.</summary>
        /// <param name="currentFilter">Filters and options dictionary.</param>
        public TinkKonradToggleViewModel(IGroupFilterMapPage currentFilter)
        {
            FilterDictionary = currentFilter ?? new GroupFilterMapPage();
        }

        /// <summary> Gets the filter values.</summary>
        public IGroupFilterMapPage FilterDictionary { get; }

        /// <summary> Gets the activated filter.</summary>
        public string CurrentFilter {
            get
            {
                return FilterDictionary.FirstOrDefault(x => x.Value == FilterState.On).Key ?? string.Empty;
            }
        }

        /// <summary> Gets value whether TINK is enabled or not. </summary>
        public bool IsTinkEnabled => !string.IsNullOrEmpty(CurrentFilter) && CurrentFilter != FilterHelper.FILTERTINKGENERAL;

        /// <summary> Gets color of the TINK button. </summary>
        public Color TinkColor => CurrentFilter == FilterHelper.FILTERTINKGENERAL ? Color.Blue : Color.Gray;

        /// <summary> Gets value whether Konrad is enabled or not. </summary>
        public bool IsKonradEnabled => !string.IsNullOrEmpty(CurrentFilter) && CurrentFilter != FilterHelper.FILTERKONRAD;

        /// <summary> Gets color of the Konrad button. </summary>
        public Color KonradColor => CurrentFilter == FilterHelper.FILTERKONRAD ? Color.Red : Color.Gray;

        /// <summary> Gets whether toggle functionality is visible or not. </summary>
        public bool IsToggleVisible =>  
            FilterDictionary.ContainsKey(FilterHelper.FILTERKONRAD) 
            && FilterDictionary.ContainsKey(FilterHelper.FILTERTINKGENERAL)
            && (IsTinkEnabled || IsKonradEnabled);

        /// <summary>
        /// Toggles from bike group TINK to Konrad or vice versa.
        /// Toggling means one of 
        /// - TINK => Konrad or
        /// - TINK => Konrad.
        /// </summary>
        /// <param name="p_strCurrentFilterSet">Filter set to toggle.</param>
        /// <returns></returns>
        public TinkKonradToggleViewModel DoToggle()
        {
            var l_oCurrentFilterSet = FilterDictionary.ToArray();

            if (l_oCurrentFilterSet.Length < 2)
            {
                // There is nothing to toggle because filter set contains only one element.
                return new TinkKonradToggleViewModel(FilterDictionary);
            }

            var l_oCurrentState = l_oCurrentFilterSet[l_oCurrentFilterSet.Length - 1].Value == FilterState.On
                ? FilterState.On
                : FilterState.Off;

            var l_oToggledFilterSet = new Dictionary<string, FilterState>();

            foreach (var l_oFilterElement in l_oCurrentFilterSet)
            {
                l_oToggledFilterSet.Add(l_oFilterElement.Key, l_oCurrentState);
                l_oCurrentState = l_oFilterElement.Value;
            }

            return new TinkKonradToggleViewModel(new GroupFilterMapPage(l_oToggledFilterSet));
        }
    }
}