Option Explicit On

Public Class Nodes

#Region "公共变量"

    Private mobjNodes As Collection
    Private mOwner As Node
    Private mobjFirstNode As Node
    Private mobjLastNode As Node
    Private mintKey As Integer

#End Region
#Region "Public属性"

    Public ReadOnly Property FirstNode() As Node
        Get
            Return mobjFirstNode
        End Get
    End Property

    Public ReadOnly Property LastNode() As Node
        Get
            Return mobjLastNode
        End Get
    End Property

    Default Public ReadOnly Property Item(ByVal Key As Object) As Node
        Get
            On Error Resume Next

            Item = mobjNodes.Item(Key)

            If Err.Number <> 0 Then
                Return Nothing
            End If
        End Get
    End Property

#End Region
#Region "Public方法"

    Public Sub New(ByVal Owner As Node)
        mobjNodes = New Collection
        mOwner = Owner
    End Sub

    Public Sub Dispose()
        Me.Dispose(True)
    End Sub

    Public Function Add() As Node
        Return Add("", "")
    End Function

    Public Function Add(ByVal Text As String) As Node
        Return Add(Text, "")
    End Function

    Public Function Add(ByVal Text As String, ByVal Tag As String) As Node
        mintKey = mintKey + 1
        Dim objNode As New Node("N" & mintKey, Text, Tag, mOwner.Level + 1, mOwner)
        If mobjNodes.Count = 0 Then
            mobjFirstNode = objNode
            mobjLastNode = objNode
        Else
            mobjLastNode.NextNode = objNode
            objNode.PrevNode = mobjLastNode
            mobjLastNode = objNode
        End If
        mobjNodes.Add(objNode, objNode.Key)

        mOwner.UpdateChindrenCount(1)
        If mOwner.Expanded Then
            mOwner.UpdateVisibleNodesCount(1)
        End If

        Return objNode
    End Function

    Public Sub Add(ByVal Count As Integer)
        Dim i As Integer
        For i = 1 To Count
            Call Add()
        Next
    End Sub

    Public Sub Clear()
        Dim i As Integer
        Dim objNode As Node

        If mobjNodes Is Nothing Then
            Return
        End If

        If mobjNodes.Count = 0 Then
            Return
        End If

        mOwner.UpdateChindrenCount(-mobjNodes.Count)
        If mOwner.Expanded Then
            mOwner.UpdateVisibleNodesCount(-mobjNodes.Count)
        End If

        mobjLastNode = Nothing
        mobjFirstNode = Nothing

        For i = mobjNodes.Count To 1 Step -1
            objNode = mobjNodes.Item(i)
            If objNode.HasChildren Then
                objNode.Nodes.Clear()
            End If
            mobjNodes.Remove(i)
        Next
    End Sub

    Public Function Count() As Integer
        Return mobjNodes.Count
    End Function

    Public Function InsertBefore(ByVal Key As String, ByVal Text As String, ByVal Tag As String) As Node
        '在指定Key的前面插入一个新的节点
        mintKey = mintKey + 1
        Dim objNode1 As Node = mobjNodes.Item(Key)
        Dim objNode2 As Node = objNode1.PrevNode
        Dim objNode As New Node("N" & mintKey, Text, Tag, mOwner.Level + 1, mOwner)

        objNode.NextNode = objNode1
        objNode.PrevNode = objNode2
        objNode1.PrevNode = objNode
        If Not objNode2 Is Nothing Then
            objNode2.NextNode = objNode
        Else
            mobjFirstNode = objNode
        End If
        mobjNodes.Add(objNode, objNode.Key)

        mOwner.UpdateChindrenCount(1)
        If mOwner.Expanded Then
            mOwner.UpdateVisibleNodesCount(1)
        End If

        Return objNode
    End Function

    Public Function InsertAfter(ByVal Key As String, ByVal Text As String, ByVal Tag As String) As Node
        '在指定Key的后面插入一个新的节点
        mintKey = mintKey + 1
        Dim objNode1 As Node = mobjNodes.Item(Key)
        Dim objNode2 As Node = objNode1.NextNode
        Dim objNode As New Node("N" & mintKey, Text, Tag, mOwner.Level + 1, mOwner)

        objNode.PrevNode = objNode1
        objNode.NextNode = objNode2
        objNode1.NextNode = objNode
        If Not objNode2 Is Nothing Then
            objNode2.PrevNode = objNode
        Else
            mobjLastNode = objNode
        End If
        mobjNodes.Add(objNode, objNode.Key)

        mOwner.UpdateChindrenCount(1)
        If mOwner.Expanded Then
            mOwner.UpdateVisibleNodesCount(1)
        End If

        Return objNode
    End Function

    Public Sub Remove(ByVal Key As Object)
        Dim objNode As Node
        objNode = mobjNodes.Item(Key)

        If mobjNodes.Count <= 1 Then
            mobjFirstNode = Nothing
            mobjLastNode = Nothing
        Else
            If objNode.PrevNode Is Nothing Then    'FirstNode
                mobjFirstNode = objNode.NextNode
                mobjFirstNode.PrevNode = Nothing
            Else
                objNode.PrevNode.NextNode = objNode.NextNode
            End If
            If objNode.NextNode Is Nothing Then    'LastNode
                mobjLastNode = objNode.PrevNode
                mobjLastNode.NextNode = Nothing
            Else
                objNode.NextNode.PrevNode = objNode.PrevNode
            End If
        End If

        If objNode.HasChildren Then
            objNode.Nodes.Clear()
        End If

        mobjNodes.Remove(Key)
        mOwner.UpdateChindrenCount(-1)
        If mOwner.Expanded Then
            mOwner.UpdateVisibleNodesCount(-1)
        End If
    End Sub

#End Region
#Region "其它"

    Protected Overrides Sub Finalize()
        Try
            Me.Dispose(False)
        Finally
            MyBase.Finalize()
        End Try
    End Sub

    Protected Overridable Sub Dispose(ByVal disposing As Boolean)
        Clear()
        mobjNodes = Nothing
        If disposing Then
            GC.SuppressFinalize(Me)
        End If
    End Sub

#End Region

End Class