Imports System
Imports System.Collections.Generic
Imports Microsoft.VisualBasic
Imports System.Collections
Imports System.Text.RegularExpressions
 
' The 'text' parameter will contain the text from the:
'   - Current Clipboard when run by HotKey
'   - History Item when run from the History Menu
' The returned String will be:
'   - Placed directly on the Clipboard
'   - Ignored by ClipboardFusion if it is 'Nothing'
Public Class ClipboardFusionHelper
 
    Public Shared Function ProcessText(text As String) As String
		Dim pattern As String = "\[[^\[\]]*\]"
      	Dim replacement As String = ""
      	Dim rgx As Regex = New Regex(pattern)
      	Dim result As String = rgx.Replace(text, replacement)
		Return calculateValue(result)
	End Function
	
	Public Shared Function calculateValue(text As String) As String
		Dim pattern As String = "[0-9\.+-/*()（）= ]+"
		Dim rgx As Regex = New Regex(pattern)
		Dim match As Boolean = rgx.IsMatch(text)
		Dim mt As MatchCollection = rgx.Matches(text)
		If(Not match) Then
			Return "The expression contains illegal characters!"
		End If

         
        Dim count As Integer = 0
        For Each m In mt
            count= count+1
        Next m
        If(count>1) Then
            Return "The expression contains illegal characters!"
        End If
         
        Dim opt_stk As Stack = New Stack()
        Dim num_stk As Stack = New Stack()
        Dim sb_temp As String = ""
 
        Dim items = text.ToCharArray
        For i = 0 To text.Length-1
            Dim c = items(i)
            If (c <> " ") Then
                If ((c >= "0" And c <= "9") Or c = "." Or (c="-" And sb_temp.Length =0)) Then
                    sb_temp = sb_temp + c
                Else
                    If (sb_temp.Length >0) Then
                        Dim temp_value As Double
                        temp_value = sb_temp
                        num_stk.push(temp_value)
                        sb_temp = ""
                    End If
 
                    Dim curOpt As String = c
                    If (opt_stk.Count = 0) Then
                        opt_stk.Push(curOpt)
                    Else
                        If (curOpt.Equals("(")) Then
                            opt_stk.Push(curOpt)
                        ElseIf (curOpt.Equals(")")) Then
                            directCalc(opt_stk, num_stk, True)
                        ElseIf (curOpt.Equals("="))
                            directCalc(opt_stk, num_stk, False)
                            Return Math.Round(num_stk.Pop,3)
                        Else
                            compareAndCalc(opt_stk, num_stk, curOpt)
                        End If
                    End If
                End If
            End If
        Next
 
        If (sb_temp.Length>0) Then
            Dim temp_value As Double
            temp_value = sb_temp
            num_stk.push(temp_value)
        End If
        directCalc(opt_stk, num_stk, False)
        Return Math.Round(num_stk.Pop,3)
    End Function
 
    Public Shared Function directCalc(optStack As Stack, numStack As Stack, isBracket As Boolean)
        Dim opt As String = optStack.Pop
        Dim num2 As Double = numStack.Pop
        Dim num1 As Double = numStack.Pop
        Dim result As Double = floatingPointCalc(opt, num1, num2)
 
        numStack.Push(result)
 
        If (isBracket) Then
            If (optStack.Peek.Equals("(")) Then
                optStack.Pop
            Else
                directCalc(optStack, numStack, isBracket)
            End If
        Else
            If (optStack.Count>0) Then
                directCalc(optStack, numStack, isBracket)
            End If
        End If
    End Function
 
    Public Shared Function compareAndCalc(optStack As Stack, numStack As Stack, curOpt As String) As Double
        Dim peekOpt = optStack.Peek
        Dim priority = getPriority(peekOpt, curOpt)
        If (priority = -1 Or priority = 0) Then
            Dim opt As String = optStack.Pop
            Dim num2 As Double = numStack.Pop
            Dim num1 As Double = numStack.Pop
            Dim result As Double = floatingPointCalc(opt, num1, num2)
 
            numStack.Push(result)
 
            If (optStack.Count = 0) Then
                optStack.Push(curOpt)
            Else
                compareAndCalc(optStack, numStack, curOpt)
            End If
        Else
            optStack.Push(curOpt)
        End If
 
    End Function
 
    Public Shared Function getPriority(opt1 As String, opt2 As String) As Integer
        Dim map As SortedList = New SortedList()
        map.Add("(", 0)
        map.Add("+", 2)
        map.Add("-", 2)
        map.Add("*", 3)
        map.Add("/", 3)
        map.Add(")", 7)
        map.Add("=", 20)
        Dim index1 = map.IndexOfKey(opt1)
        Dim value1 = map.GetByIndex(index1)
        Dim index2 = map.IndexOfKey(opt2)
        Dim value2 = map.GetByIndex(index2)
        Return value2 - value1
    End Function
 
    Public Shared Function floatingPointCalc(opt As String, val1 As Double, val2 As Double) As Double
        Dim result As Double
        If (opt.Equals("+")) Then
            result = val1 + val2
        End If
        If (opt.Equals("-")) Then
            result = val1 - val2
        End If
        If (opt.Equals("*")) Then
            result = val1 * val2
        End If
        If (opt.Equals("/")) Then
            result = val1 / val2
        End If
        Return result
    End Function
 
End Class