Namespace lemoncake.samples
    Imports System
    Imports System.Collections.Generic
    Imports System.Collections
    Imports System.Text
    Imports System.ComponentModel
    
    
    Public Class BindingListView
        Inherits BindingList
        Implements IBindingListView, IRaiseItemChangedEvents
        
        Private m_Sorted As Boolean = false
        
        Private m_Filtered As Boolean = false
        
        Private m_FilterString As String = Nothing
        
        Private m_SortDirection As ListSortDirection = ListSortDirection.Ascending
        
        Private m_SortProperty As PropertyDescriptor = Nothing
        
        Private m_SortDescriptions As ListSortDescriptionCollection = New ListSortDescriptionCollection
        
        Private m_OriginalCollection As List = New List
        
        Public Sub New()
            MyBase.New
            
        End Sub
        
        Public Sub New(ByVal list As List)
            MyBase.New(list)
            
        End Sub
        
        Protected Overrides ReadOnly Property SupportsSearchingCore As Boolean
            Get
                Return true
            End Get
        End Property
        
        Protected Overrides ReadOnly Property SupportsSortingCore As Boolean
            Get
                Return true
            End Get
        End Property
        
        Protected Overrides ReadOnly Property IsSortedCore As Boolean
            Get
                Return m_Sorted
            End Get
        End Property
        
        Protected Overrides ReadOnly Property SortDirectionCore As ListSortDirection
            Get
                Return m_SortDirection
            End Get
        End Property
        
        Protected Overrides ReadOnly Property SortPropertyCore As PropertyDescriptor
            Get
                Return m_SortProperty
            End Get
        End Property
        
        Property IBindingListView_Filter As String Implements IBindingListView.Filter
            Get
                Return m_FilterString
            End Get
            Set
                m_FilterString = value
                m_Filtered = true
                UpdateFilter
            End Set
        End Property
        
        ReadOnly Property IBindingListView_SortDescriptions As ListSortDescriptionCollection Implements IBindingListView.SortDescriptions
            Get
                Return m_SortDescriptions
            End Get
        End Property
        
        ReadOnly Property IBindingListView_SupportsAdvancedSorting As Boolean Implements IBindingListView.SupportsAdvancedSorting
            Get
                Return true
            End Get
        End Property
        
        ReadOnly Property IBindingListView_SupportsFiltering As Boolean Implements IBindingListView.SupportsFiltering
            Get
                Return true
            End Get
        End Property
        
        ReadOnly Property IBindingList_AllowNew As Boolean Implements IBindingList.AllowNew
            Get
                Return CheckReadOnly
            End Get
        End Property
        
        ReadOnly Property IBindingList_AllowRemove As Boolean Implements IBindingList.AllowRemove
            Get
                Return CheckReadOnly
            End Get
        End Property
        
        ReadOnly Property IRaiseItemChangedEvents_RaisesItemChangedEvents As Boolean Implements IRaiseItemChangedEvents.RaisesItemChangedEvents
            Get
                Return true
            End Get
        End Property
        
        Protected Overrides Function FindCore(ByVal property As PropertyDescriptor, ByVal key As Object) As Integer
            ' Simple iteration:
            Dim i As Integer = 0
            Do While (i < Count)
                Dim item As T = Me(i)
                If property.GetValue(item).Equals(key) Then
                    Return i
                End If
                i = (i + 1)
            Loop
            Return -1
            ' Not found
            ' Alternative search implementation
            ' using List.FindIndex:
            'Predicate<T> pred = delegate(T item)
            '{
            ' if (property.GetValue(item).Equals(key))
            ' return true;
            ' else
            ' return false;
            '};
            'List<T> list = Items as List<T>;
            'if (list == null)
            ' return -1;
            'return list.FindIndex(pred);
        End Function
        
        Protected Overrides Sub ApplySortCore(ByVal property As PropertyDescriptor, ByVal direction As ListSortDirection)
            m_SortDirection = direction
            m_SortProperty = property
            Dim comparer As SortComparer = New SortComparer(property, direction)
            ApplySortInternal(comparer)
        End Sub
        
        Private Sub ApplySortInternal(ByVal comparer As SortComparer)
            If (m_OriginalCollection.Count = 0) Then
                m_OriginalCollection.AddRange(Me)
            End If
            Dim listRef As List = CType(Me.Items,List)
            If (listRef Is Nothing) Then
                Return
            End If
            listRef.Sort(comparer)
            m_Sorted = true
            OnListChanged(New ListChangedEventArgs(ListChangedType.Reset, -1))
        End Sub
        
        Protected Overrides Sub RemoveSortCore()
            If Not m_Sorted Then
                Return
            End If
            Clear
            For Each item As T In m_OriginalCollection
                Add(item)
            Next
            m_OriginalCollection.Clear
            m_SortProperty = Nothing
            m_SortDescriptions = Nothing
            m_Sorted = false
        End Sub
        
        Sub IBindingListView_ApplySort(ByVal sorts As ListSortDescriptionCollection) Implements IBindingListView.ApplySort
            m_SortProperty = Nothing
            m_SortDescriptions = sorts
            Dim comparer As SortComparer = New SortComparer(sorts)
            ApplySortInternal(comparer)
        End Sub
        
        Sub IBindingListView_RemoveFilter() Implements IBindingListView.RemoveFilter
            If Not m_Filtered Then
                Return
            End If
            m_FilterString = Nothing
            m_Filtered = false
            m_Sorted = false
            m_SortDescriptions = Nothing
            m_SortProperty = Nothing
            Clear
            For Each item As T In m_OriginalCollection
                Add(item)
            Next
            m_OriginalCollection.Clear
        End Sub
        
        Protected Overridable Sub UpdateFilter()
            Dim equalsPos As Integer = m_FilterString.IndexOf(Microsoft.VisualBasic.ChrW(61))
            ' Get property name
            Dim propName As String = m_FilterString.Substring(0, equalsPos).Trim
            ' Get filter criteria
            Dim criteria As String = m_FilterString.Substring((equalsPos + 1), (m_FilterString.Length  _
                            - (equalsPos - 1))).Trim
            ' Strip leading and trailing quotes
            criteria = criteria.Substring(1, (criteria.Length - 2))
            ' Get a property descriptor for the filter property
            Dim propDesc As PropertyDescriptor = TypeDescriptor.GetProperties(GetType(T))(propName)
            If (m_OriginalCollection.Count = 0) Then
                m_OriginalCollection.AddRange(Me)
            End If
            Dim currentCollection As List = New List(Me)
            Clear
            For Each item As T In currentCollection
                Dim value As Object = propDesc.GetValue(item)
                ' strip newline characters as it was causing issues with contains
                Dim sval As String = value.ToString.Replace(""& vbLf, "").Replace(""& vbCr, "")
                If sval.ToString.Contains(criteria) Then
                    Add(item)
                End If
            Next
        End Sub
        
        Private Function CheckReadOnly() As Boolean
            If (m_Sorted OrElse m_Filtered) Then
                Return false
            Else
                Return true
            End If
        End Function
        
        Protected Overrides Sub InsertItem(ByVal index As Integer, ByVal item As T)
            For Each propDesc As PropertyDescriptor In TypeDescriptor.GetProperties(item)
                If propDesc.SupportsChangeEvents Then
                    propDesc.AddValueChanged(item, OnItemChanged)
                End If
            Next
            MyBase.InsertItem(index, item)
        End Sub
        
        Protected Overrides Sub RemoveItem(ByVal index As Integer)
            Dim item As T = Items(index)
            Dim propDescs As PropertyDescriptorCollection = TypeDescriptor.GetProperties(item)
            For Each propDesc As PropertyDescriptor In propDescs
                If propDesc.SupportsChangeEvents Then
                    propDesc.RemoveValueChanged(item, OnItemChanged)
                End If
            Next
            MyBase.RemoveItem(index)
        End Sub
        
        Private Sub OnItemChanged(ByVal sender As Object, ByVal args As EventArgs)
            Dim index As Integer = Items.IndexOf(CType(sender,T))
            OnListChanged(New ListChangedEventArgs(ListChangedType.ItemChanged, index))
        End Sub
    End Class
    
    Class SortComparer
        Inherits IComparer
        
        Private m_SortCollection As ListSortDescriptionCollection = Nothing
        
        Private m_PropDesc As PropertyDescriptor = Nothing
        
        Private m_Direction As ListSortDirection = ListSortDirection.Ascending
        
        Public Sub New(ByVal propDesc As PropertyDescriptor, ByVal direction As ListSortDirection)
            MyBase.New
            m_PropDesc = propDesc
            m_Direction = direction
        End Sub
        
        Public Sub New(ByVal sortCollection As ListSortDescriptionCollection)
            MyBase.New
            m_SortCollection = sortCollection
        End Sub
        
        Function IComparer_Compare(ByVal x As T, ByVal y As T) As Integer Implements IComparer.Compare
            If (Not (m_PropDesc) Is Nothing) Then
                Dim xValue As Object = m_PropDesc.GetValue(x)
                Dim yValue As Object = m_PropDesc.GetValue(y)
                Return CompareValues(xValue, yValue, m_Direction)
            ElseIf ((Not (m_SortCollection) Is Nothing)  _
                        AndAlso (m_SortCollection.Count > 0)) Then
                Return RecursiveCompareInternal(x, y, 0)
            Else
                Return 0
            End If
        End Function
        
        Private Function CompareValues(ByVal xValue As Object, ByVal yValue As Object, ByVal direction As ListSortDirection) As Integer
            Dim retValue As Integer = 0
            If (TypeOf xValue Is IComparable) Then
                retValue = CType(xValue,IComparable).CompareTo(yValue)
            ElseIf (TypeOf yValue Is IComparable) Then
                retValue = CType(yValue,IComparable).CompareTo(xValue)
            End If
            ' not comparable, compare String representations
            If Not xValue.Equals(yValue) Then
                retValue = xValue.ToString.CompareTo(yValue.ToString)
            End If
            If (direction = ListSortDirection.Ascending) Then
                Return retValue
            Else
                Return (retValue * -1)
            End If
        End Function
        
        Private Function RecursiveCompareInternal(ByVal x As T, ByVal y As T, ByVal index As Integer) As Integer
            If (index >= m_SortCollection.Count) Then
                Return 0
            End If
            ' termination condition
            Dim listSortDesc As ListSortDescription = m_SortCollection(index)
            Dim xValue As Object = listSortDesc.PropertyDescriptor.GetValue(x)
            Dim yValue As Object = listSortDesc.PropertyDescriptor.GetValue(y)
            Dim retValue As Integer = CompareValues(xValue, yValue, listSortDesc.SortDirection)
            If (retValue = 0) Then
                Return RecursiveCompareInternal(x, y, ++, index)
            Else
                Return retValue
            End If
        End Function
    End Class
End Namespace