Imports System
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Windows.Forms
Imports System.Drawing

Public Class Highlighter
    Inherits Component

    Private _Highlights As Dictionary(Of Control, eHighlightColor) = New Dictionary(Of Control, eHighlightColor)()
    Private _HighlightOnFocus As Dictionary(Of Control, Boolean) = New Dictionary(Of Control, Boolean)()

    Protected Overrides Sub Dispose(ByVal disposing As Boolean)
        If _ContainerControl IsNot Nothing Then
            RemoveHandler _ContainerControl.SizeChanged, AddressOf ContainerControlSizeChanged
            RemoveHandler _ContainerControl.HandleCreated, AddressOf ContainerControlHandleCreated
        End If

        If _HighlightPanel IsNot Nothing AndAlso _HighlightPanel.Parent Is Nothing AndAlso Not _HighlightPanel.IsDisposed Then
            _HighlightPanel.Dispose()
            _HighlightPanel = Nothing
        Else
            _HighlightPanel = Nothing
        End If

        MyBase.Dispose(disposing)
    End Sub

    <DefaultValue(False), Localizable(True), Description("Indicates whether control is highlighted when it receives input focus.")>
    Public Function GetHighlightOnFocus(ByVal c As Control) As Boolean
        If _HighlightOnFocus.ContainsKey(c) Then
            Return _HighlightOnFocus(c)
        End If

        Return False
    End Function

    Public Sub SetHighlightOnFocus(ByVal c As Control, ByVal highlight As Boolean)
        If c Is Nothing Then Throw New NullReferenceException()

        If _HighlightOnFocus.ContainsKey(c) Then

            If Not highlight Then
                RemoveHighlightOnFocus(_HighlightOnFocus, c)
            End If

            Return
        End If

        If highlight Then AddHighlightOnFocus(_HighlightOnFocus, c)
    End Sub

    Private Sub AddHighlightOnFocus(ByVal highlightOnFocus As Dictionary(Of Control, Boolean), ByVal c As Control)
        AddHandler c.Enter, AddressOf ControlHighlightEnter
        AddHandler c.Leave, AddressOf ControlHighlightLeave
        AddHandler c.VisibleChanged, AddressOf ControlHighlightVisibleChanged
        highlightOnFocus.Add(c, True)
    End Sub

    Private Sub ControlHighlightVisibleChanged(ByVal sender As Object, ByVal e As EventArgs)
        If _HighlightPanel IsNot Nothing AndAlso _HighlightPanel.FocusHighlightControl = sender Then UpdateHighlighterRegion()
    End Sub

    Private Sub ControlHighlightLeave(ByVal sender As Object, ByVal e As EventArgs)
        If _HighlightPanel IsNot Nothing Then _HighlightPanel.FocusHighlightControl = Nothing
        UpdateHighlighterRegion()
    End Sub

    Private Sub ControlHighlightEnter(ByVal sender As Object, ByVal e As EventArgs)
        If _HighlightPanel IsNot Nothing Then
            If Not _HighlightPanel.Visible Then _HighlightPanel.Visible = True
            _HighlightPanel.BringToFront()
            _HighlightPanel.FocusHighlightControl = CType(sender, Control)
        End If

        UpdateHighlighterRegion()
    End Sub

    Private Sub RemoveHighlightOnFocus(ByVal highlightOnFocus As Dictionary(Of Control, Boolean), ByVal c As Control)
        RemoveHandler c.Enter, AddressOf ControlHighlightEnter
        RemoveHandler c.Leave, AddressOf ControlHighlightLeave
        RemoveHandler c.VisibleChanged, AddressOf ControlHighlightVisibleChanged
        highlightOnFocus.Remove(c)
    End Sub

    <DefaultValue(eHighlightColor.None), Localizable(True), Description("Indicates the highlight color that is applied to the control.")>
    Public Function GetHighlightColor(ByVal c As Control) As eHighlightColor
        If _Highlights.ContainsKey(c) Then
            Return _Highlights(c)
        End If

        Return eHighlightColor.None
    End Function

    Public Sub SetHighlightColor(ByVal c As Control, ByVal highlightColor As eHighlightColor)
        If _Highlights.ContainsKey(c) Then

            If highlightColor = eHighlightColor.None Then
                RemoveHighlight(_Highlights, c)
            Else
                Dim color As eHighlightColor = _Highlights(c)
                RemoveHighlight(_Highlights, c)
                AddHighlight(_Highlights, c, highlightColor)
            End If
        ElseIf highlightColor <> eHighlightColor.None Then
            AddHighlight(_Highlights, c, highlightColor)
        End If
    End Sub

    Private _TabControl2 As Dictionary(Of System.Windows.Forms.TabControl, Integer) = New Dictionary(Of System.Windows.Forms.TabControl, Integer)()
    Private _ParentPanel As Dictionary(Of Panel, Integer) = New Dictionary(Of Panel, Integer)()

    Private Sub AddHighlight(ByVal highlights As Dictionary(Of Control, eHighlightColor), ByVal c As Control, ByVal highlightColor As eHighlightColor)
        highlights.Add(c, highlightColor)
        AddHandler c.LocationChanged, New EventHandler(AddressOf ControlLocationChanged)
        AddHandler c.SizeChanged, New EventHandler(AddressOf ControlSizeChanged)
        AddHandler c.VisibleChanged, New EventHandler(AddressOf ControlVisibleChanged)

        If _HighlightPanel IsNot Nothing Then
            If Not _HighlightPanel.Visible Then _HighlightPanel.Visible = True
            _HighlightPanel.BringToFront()
        End If

        If c.Parent Is Nothing Then
            AddHandler c.ParentChanged, AddressOf ControlParentChanged
        Else
            AddTabControlHandlers(c)
        End If

        UpdateHighlighterRegion()
    End Sub

    Private Sub ControlParentChanged(ByVal sender As Object, ByVal e As EventArgs)
        Dim c As Control = CType(sender, Control)
        RemoveHandler c.ParentChanged, AddressOf ControlParentChanged
        AddTabControlHandlers(c)
    End Sub

    Private Sub AddTabControlHandlers(ByVal c As Control)
        Dim tab2 As System.Windows.Forms.TabControl = TryCast(GetParentControl(c, GetType(System.Windows.Forms.TabControl)), System.Windows.Forms.TabControl)

        If tab2 IsNot Nothing Then

            If _TabControl2.ContainsKey(tab2) Then
                _TabControl2(tab2) = _TabControl2(tab2) + 1
            Else
                _TabControl2.Add(tab2, 1)
                AddHandler tab2.SelectedIndexChanged, AddressOf WinFormsTabSelectedIndexChanged
            End If
        Else
            Dim parentPanel As Panel = TryCast(GetParentControl(c, GetType(Panel)), Panel)

            If parentPanel IsNot Nothing Then

                If _ParentPanel.ContainsKey(parentPanel) Then
                    _ParentPanel(parentPanel) = _ParentPanel(parentPanel) + 1
                Else
                    _ParentPanel.Add(parentPanel, 1)
                    AddHandler parentPanel.Resize, AddressOf ParentPanelResized
                    AddHandler parentPanel.LocationChanged, AddressOf ParentPanelLocationChanged
                End If
            End If
        End If
    End Sub

    Private Sub ParentPanelLocationChanged(ByVal sender As Object, ByVal e As EventArgs)
        UpdateHighlights()
    End Sub

    Private Sub ParentPanelResized(ByVal sender As Object, ByVal e As EventArgs)
        UpdateHighlights()
    End Sub

    Private Sub WinFormsTabSelectedIndexChanged(ByVal sender As Object, ByVal e As EventArgs)
        UpdateHighlighterRegion()
    End Sub

    Private Function GetParentControl(ByVal c As Control, ByVal parentType As Type) As Control
        Dim parent As Control = c.Parent

        While parent IsNot Nothing
            If parentType.IsAssignableFrom(parent.[GetType]()) Then Return parent
            parent = parent.Parent
        End While

        Return Nothing
    End Function

    Private Sub ControlVisibleChanged(ByVal sender As Object, ByVal e As EventArgs)
        UpdateHighlighterRegion()
    End Sub

    Private Sub ControlSizeChanged(ByVal sender As Object, ByVal e As EventArgs)
        UpdateHighlighterRegion()
    End Sub

    Private Sub ControlLocationChanged(ByVal sender As Object, ByVal e As EventArgs)
        UpdateHighlighterRegion()
    End Sub

    Private Sub UpdateHighlighterRegion()
        If _HighlightPanel IsNot Nothing Then _HighlightPanel.UpdateRegion()
    End Sub

    Public Sub UpdateHighlights()
        UpdateHighlighterRegion()
    End Sub

    Private Sub RemoveHighlight(ByVal highlights As Dictionary(Of Control, eHighlightColor), ByVal c As Control)
        highlights.Remove(c)
        RemoveHandler c.LocationChanged, New EventHandler(AddressOf ControlLocationChanged)
        RemoveHandler c.SizeChanged, New EventHandler(AddressOf ControlSizeChanged)
        RemoveHandler c.VisibleChanged, New EventHandler(AddressOf ControlVisibleChanged)
        Dim tab2 As System.Windows.Forms.TabControl = TryCast(GetParentControl(c, GetType(System.Windows.Forms.TabControl)), System.Windows.Forms.TabControl)

        If tab2 IsNot Nothing Then

            If _TabControl2.ContainsKey(tab2) Then

                If _TabControl2(tab2) = 1 Then
                    _TabControl2.Remove(tab2)
                    RemoveHandler tab2.SelectedIndexChanged, AddressOf WinFormsTabSelectedIndexChanged
                Else
                    _TabControl2(tab2) = _TabControl2(tab2) - 1
                End If
            End If
        Else
            Dim parentPanel As Panel = TryCast(GetParentControl(c, GetType(Panel)), Panel)

            If parentPanel IsNot Nothing Then

                If _ParentPanel.ContainsKey(parentPanel) Then

                    If _ParentPanel(parentPanel) = 1 Then
                        _ParentPanel.Remove(parentPanel)
                        RemoveHandler parentPanel.LocationChanged, AddressOf ParentPanelLocationChanged
                        RemoveHandler parentPanel.SizeChanged, AddressOf ParentPanelResized
                    Else
                        _ParentPanel(parentPanel) = _ParentPanel(parentPanel) - 1
                    End If
                End If
            End If
        End If

        UpdateHighlighterRegion()
    End Sub

    Friend ReadOnly Property Highlights As Dictionary(Of Control, eHighlightColor)
        Get
            Return _Highlights
        End Get
    End Property

    Private _FocusHighlightColor As eHighlightColor = eHighlightColor.Blue

    <DefaultValue(eHighlightColor.Blue), Category("Appearance"), Description("Indicates the highlight focus color."), Localizable(True)>
    Public Property FocusHighlightColor As eHighlightColor
        Get
            Return _FocusHighlightColor
        End Get
        Set(ByVal value As eHighlightColor)
            _FocusHighlightColor = value

            If _HighlightPanel IsNot Nothing Then
                _HighlightPanel.FocusHighlightColor = value
                UpdateHighlighterRegion()
            End If
        End Set
    End Property

    Private _HighlightPanel As HighlightPanel = Nothing
    Private _ContainerControl As Control = Nothing

    <Description("Indicates container control highlighter is bound to. Should be set to parent form."), Category("Behavior")>
    Public Property ContainerControl As Control
        Get
            Return _ContainerControl
        End Get
        Set(ByVal value As Control)

            If Me.DesignMode Then
                _ContainerControl = value
                Return
            End If

            If _ContainerControl IsNot value Then

                If _ContainerControl IsNot Nothing Then
                    RemoveHandler _ContainerControl.SizeChanged, AddressOf ContainerControlSizeChanged
                    RemoveHandler _ContainerControl.HandleCreated, AddressOf ContainerControlHandleCreated
                    If _HighlightPanel IsNot Nothing AndAlso _HighlightPanel.Parent Is _ContainerControl Then _ContainerControl.Controls.Remove(_HighlightPanel)
                End If

                _ContainerControl = value

                If _ContainerControl IsNot Nothing Then

                    If _HighlightPanel Is Nothing Then
                        _HighlightPanel = New HighlightPanel(_Highlights)
                        _HighlightPanel.FocusHighlightColor = _FocusHighlightColor
                        _HighlightPanel.Margin = New System.Windows.Forms.Padding(0)
                        _HighlightPanel.Padding = New System.Windows.Forms.Padding(0)
                        _HighlightPanel.CustomHighlightColors = _CustomHighlightColors
                        _HighlightPanel.Visible = False
                    End If

                    AddHandler _ContainerControl.SizeChanged, AddressOf ContainerControlSizeChanged
                    AddHandler _ContainerControl.HandleCreated, AddressOf ContainerControlHandleCreated
                    _ContainerControl.Controls.Add(_HighlightPanel)
                    UpdateHighlightPanelBounds()
                End If
            End If
        End Set
    End Property

    Private Sub ContainerControlHandleCreated(ByVal sender As Object, ByVal e As EventArgs)
        If _Highlights.Count > 0 AndAlso _HighlightPanel IsNot Nothing AndAlso Not _HighlightPanel.Visible Then _HighlightPanel.Visible = True
    End Sub

    Private Sub UpdateHighlightPanelBounds()
        Dim bounds As Rectangle = New Rectangle(0, 0, _ContainerControl.ClientRectangle.Width, _ContainerControl.ClientRectangle.Height)

        If TypeOf _HighlightPanel.Parent Is Form Then
            Dim form As Form = TryCast(_HighlightPanel.Parent, Form)

            If form.AutoSize Then
                bounds.X += form.Padding.Left
                bounds.Y += form.Padding.Top
                bounds.Width -= form.Padding.Horizontal
                bounds.Height -= form.Padding.Vertical
            End If
        End If

        If _HighlightPanel.Bounds.Equals(bounds) Then
            _HighlightPanel.UpdateRegion()
        Else
            _HighlightPanel.Bounds = bounds
        End If

        _HighlightPanel.BringToFront()
    End Sub

    Private _DelayTimer As Timer = Nothing

    Private Sub ContainerControlSizeChanged(ByVal sender As Object, ByVal e As EventArgs)
        Dim form As Form = TryCast(sender, Form)

        If form IsNot Nothing Then

            If _DelayTimer Is Nothing Then
                _DelayTimer = New Timer()
                _DelayTimer.Interval = 100
                AddHandler _DelayTimer.Tick, New EventHandler(AddressOf DelayTimerTick)
                _DelayTimer.Start()
            End If

            Return
        End If

        UpdateHighlightPanelBounds()
    End Sub

    Private Sub DelayTimerTick(ByVal sender As Object, ByVal e As EventArgs)
        Dim timer As Timer = _DelayTimer
        _DelayTimer = Nothing
        RemoveHandler timer.Tick, New EventHandler(AddressOf DelayTimerTick)
        timer.[Stop]()
        timer.Dispose()
        UpdateHighlightPanelBounds()
    End Sub

    Private _CustomHighlightColors As Color() = Nothing

    <Category("Appearance"), Description("Array of colors used to render custom highlight color. Control expects 3 colors in array to be specified which define the highlight border.")>
    Public Property CustomHighlightColors As Color()
        Get
            Return _CustomHighlightColors
        End Get
        Set(ByVal value As Color())
            _CustomHighlightColors = value

            If _HighlightPanel IsNot Nothing Then
                _HighlightPanel.CustomHighlightColors = _CustomHighlightColors
                _HighlightPanel.Invalidate()
            End If
        End Set
    End Property

    Public Function CanExtend(ByVal extendee As Object) As Boolean
        Return (TypeOf extendee Is Control)
    End Function

    Private Sub SetError(ByVal control As Control, ByVal value As String)
        Me.SetHighlightColor(control, eHighlightColor.Red)
    End Sub

    Private Sub ClearError(ByVal control As Control)
        Me.SetHighlightColor(control, eHighlightColor.None)
    End Sub
End Class

Public Enum eHighlightColor
    None
    Red
    Blue
    Green
    Orange
    Custom
End Enum