'**************************************************
' FILE      : BBCodeElement.vb
' AUTHOR    : Paulo Santos
' CREATION  : 4/29/2009 11:33:36 AM
' COPYRIGHT : Copyright © 2009
'             PJ on Development
'             All Rights Reserved.
'
' Description:
'       TODO: Add file description
'
' Change log:
' 0.1   4/29/2009 11:33:36 AM
'       Paulo Santos
'       Created.
'***************************************************

Imports System.Globalization
Imports System.Text.RegularExpressions

''' <summary>
''' Represents an BBCode element.
''' </summary>
Public Class BBCodeElement(Of TContext As Class)
	Inherits BBCodeNode(Of TContext)

	Private __Name As String
	Private __Nodes As BBCodeNodeCollection(Of TContext)
	Private __Attributes As BBCodeAttributeDictionary
	Private __ReplacementFormat As String = String.Empty
	Private __RequireClosingTag As TriState = TriState.UseDefault
	Private __IsValueFormatted As Boolean

	Private Shared ReadOnly __RxAttribute As New Regex("\{(?<name>[_a-zA-Z0-9].*?)\}")

	''' <summary>Initializes an instance of the <see cref="BBCodeElement" /> class.
	''' This is the default constructor for this class.</summary>
	Friend Sub New()
	End Sub

	''' <summary>Initializes an instance of the <see cref="BBCodeElement" /> class.</summary>
	''' <param name="name">The name of the element.</param>
	Protected Sub New(ByVal name As String)
		__Name = name.ToUpperInvariant()
	End Sub

	''' <summary>Initializes an instance of the <see cref="BBCodeElement" /> class.</summary>
	''' <param name="parser">The parser used to create this element.</param>
	Friend Sub New(ByVal parser As BBCodeParser(Of TContext))
		MyBase.New(parser)
	End Sub

	''' <summary>
	''' Gets the name of the element.
	''' </summary>
	Public ReadOnly Property Name() As String
		Get
			Return __Name
		End Get
	End Property

	''' <summary>
	''' Gets the replacement format for this element.
	''' </summary>
	''' <value>The replacement format.</value>
	''' <remarks>
	''' <para>In order to use the any parameter in the replacement format use the following syntax: {paramName}.</para>
	''' <para/>
	''' <para>The parameter names are case insensitive.</para>
	''' <para/>
	''' <para>There are two reserved parameter keywords for formatting: DEFAULT and VALUE.</para>
	''' <para><c>DEFAULT</c> : The text following the first equal sign after the name of the BBCode element.</para>
	''' <para><c>VALUE</c>: The HTML generated by the BBCode between the start and end element tag.</para>
	''' <para><example>[url=http://tempuri.org]text[/url]</example></para>
	''' <para>In the example above the parameter DEFAULT would have the value "http://tempuri.org", while VALUE would be "text".</para>
	''' <para/>
	''' <para>To replace [url=http://tempuri.org]text[/url] the with &lt;a href="http://tempuri.org"&gt;text&lt;/a&gt; the following ReplacementFormat should be used:</para>
	''' <example>
	''' &lt;a href="{default|value}"&gt;{value|default}&lt;/a&gt;
	''' </example>
	''' <para>The example above, will set the href attribute with either the default value or the text inside the [url] element. The pipe (|) implies in finding the first non-empty attribute.</para>
	''' </remarks>
	Public ReadOnly Property ReplacementFormat() As String
		Get
			If (String.IsNullOrEmpty(__ReplacementFormat)) Then
				If (Me.Parser.Dictionary.ContainsKey(Me.Name)) Then
					__ReplacementFormat = Me.Parser.Dictionary(Me.Name).ReplacementFormat
				End If
			End If
			Return __ReplacementFormat
		End Get
	End Property

	''' <summary>
	''' Gets a value indicating if the element requires a closing tag.
	''' </summary>
	''' <value><c>True</c> if the element requires a closing tag; otherwise <c>False</c>.</value>
	Public ReadOnly Property RequireClosingTag() As Boolean
		Get
			If (__RequireClosingTag = TriState.UseDefault) Then
				If (Not String.IsNullOrEmpty(Me.Name) AndAlso Me.Parser.Dictionary.ContainsKey(Me.Name)) Then
					__RequireClosingTag = If(Me.Parser.Dictionary(Me.Name).RequireClosingTag, TriState.True, TriState.False)
				ElseIf (Not String.IsNullOrEmpty(Me.Name) AndAlso Me.Parser.ElementTypes.ContainsKey(Me.Name)) Then
					__RequireClosingTag = If(Me.Parser.ElementTypes(Me.Name).RequireClosingTag, TriState.True, TriState.False)
				End If
			End If
			Return (__RequireClosingTag = TriState.True)
		End Get
	End Property

	''' <summary>
	''' Gets the list of attributes.
	''' </summary>
	Public ReadOnly Property Attributes() As BBCodeAttributeDictionary
		Get
			If (__Attributes Is Nothing) Then
				__Attributes = New BBCodeAttributeDictionary
			End If
			Return __Attributes
		End Get
	End Property

	''' <summary>
	''' Gets the list of sub nodes.
	''' </summary>
	Public ReadOnly Property Nodes() As BBCodeNodeCollection(Of TContext)
		Get
			If (__Nodes Is Nothing) Then
				__Nodes = New BBCodeNodeCollection(Of TContext)(Me)
			End If
			Return __Nodes
		End Get
	End Property

	''' <summary>Transforms this instance of <see cref="BBCodeElement" /> into its desired text representation.</summary>
	''' <param name="formatter">An object that implements the <see cref="ITextFormatter" /> interface.</param>
	''' <returns>The text formatted by the <see cref="ITextFormatter" />.</returns>
	Public Overrides Function Format(ByVal context As TContext, ByVal formatter As ITextFormatter) As String
		IsValueFormatted = False
		Dim sb As New Text.StringBuilder(Me.ReplacementFormat)
		Dim attribs = __RxAttribute.Matches(Me.ReplacementFormat)
		For Each attrib As Match In attribs
			sb.Replace(attrib.Value, GetAttribute(attrib.Groups("name").Value, context, formatter))
		Next
		If Not IsValueFormatted Then
			sb.Append(GetAttribute("value", context, formatter))
		End If
		Return sb.ToString()
	End Function

	''' <summary>Gets or sets the inner </summary>
	''' <value>The BBCode between the start and end tags.</value>
	Public NotOverridable Overrides Property InnerBBCode() As String
		Get
			Dim sb As New System.Text.StringBuilder()
			For Each n As BBCodeNode(Of TContext) In Nodes
				sb.Append(n.OuterBBCode)
			Next
			Return sb.ToString()
		End Get
		Set(ByVal value As String)
			If Not RequireClosingTag Then
				Throw New InvalidOperationException("The InnerBBCode property cannot be set for elements that does not require closing tags.")
			End If
			Me.Nodes.Clear()
			Me.Nodes.AddRange(Me.Parser.Parse(value).Nodes)
		End Set
	End Property

	''' <summary>Gets or sets the outer </summary>
	''' <value>The BBCode of this instance of the <see cref="BBCodeNode" /> .</value>
	Public NotOverridable Overrides ReadOnly Property OuterBBCode() As String
		Get
			Dim sb As New Text.StringBuilder()
			sb.Append("[")
			sb.Append(Me.Name)
			If ((Me.Attributes.Count = 1) AndAlso Me.Attributes.ContainsKey("default")) Then
				sb.AppendFormat(CultureInfo.InvariantCulture, "={0}", Quote(Me.Attributes("default")))
			Else
				For Each key In Me.Attributes.Keys
					sb.AppendFormat(CultureInfo.InvariantCulture, " {0}={1}", key, Quote(Me.Attributes(key)))
				Next
			End If
			If (Me.RequireClosingTag) Then
				sb.Append("]")
				sb.Append(Me.InnerBBCode)
				sb.Append("[/")
				sb.Append(Me.Name)
			End If
			sb.Append("]")
			Return sb.ToString()
		End Get
	End Property

	''' <summary>Gets or sets the plain text of the node.</summary>
	''' <value>The plain text between the start and end tags.</value>
	Public NotOverridable Overrides Property InnerText() As String
		Get
			Dim sb As New Text.StringBuilder()
			For Each n In Me.Nodes
				sb.Append(n.InnerText)
			Next
			Return sb.ToString()
		End Get
		Set(ByVal value As String)
			If (Not RequireClosingTag) Then
				Throw New InvalidOperationException("The InnerText property cannot be set for elements that does not require closing tags.")
			End If

			'*
			'* Removes all nodex from the element
			'*
			Me.Nodes.Clear()
			If (Not String.IsNullOrEmpty(value)) Then
				'*
				'* Only append a BBCodeText element if the value is not empty
				'*
				Me.Nodes.Add(New BBCodeText(Of TContext)(value))
			End If
		End Set
	End Property

	''' <summary>
	''' Sets the element name of this instance.
	''' </summary>
	''' <param name="name">The new element name of this instance.</param>
	Friend Sub SetName(ByVal name As String)
		__Name = name
	End Sub

	''' <summary>
	''' Gets a value indicating wheter or not the <see cref="BBCodeElement.Nodes"/> have been formatted.
	''' </summary>
	''' <returns><c>True</c> if the values have been formatted; otherwise <c>False</c>.</returns>
	Private Property IsValueFormatted() As Boolean
		Get
			Return __IsValueFormatted
		End Get
		Set(ByVal value As Boolean)
			__IsValueFormatted = value
		End Set
	End Property

	Private Function GetAttribute(ByVal name As String, ByVal context As TContext, ByVal formatter As ITextFormatter) As String
		Dim attribs = name.ToUpperInvariant().Split("|".ToCharArray(), StringSplitOptions.RemoveEmptyEntries)
		For Each attrib In attribs
			If (String.CompareOrdinal(attrib, "VALUE") = 0) Then
				IsValueFormatted = True
				Dim sb As New Text.StringBuilder()
				For Each node In Me.Nodes
					sb.Append(node.Format(context, formatter))
				Next
				Return sb.ToString()
			ElseIf (Me.Attributes.ContainsKey(attrib)) Then
				Return (Me.Attributes.Item(attrib))
			End If
		Next
		Return String.Empty
	End Function

End Class