Public Class Form1
    Dim question(99) As String
    Dim input(99) As String
    Dim exInput(99, 99) As String
    Dim output(99) As String
    Dim exOutput(99, 99) As String
    Dim example(99) As String
    Dim num As Integer

    Public TextBox1 As New TextBox '宣告前端控制項
    Public TextBox2 As New TextBox
    Public TextBox3 As New TextBox
    Public Button1 As New Button
    Public Button2 As New Button
    Public Button3 As New Button
    Public Label1 As New Label
    Public ComboBox1 As New ComboBox
    Public CheckBox1 As New CheckBox

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        '前端控制項屬性設定
        Me.Size = New Size(555, 335)

        TextBox1.Name = "TextBox1"
        TextBox1.Location = New Point(305, 30)
        TextBox1.Size = New Size(220, 225)
        TextBox1.Multiline = True
        TextBox1.ScrollBars = ScrollBars.Both
        Me.Controls.Add(TextBox1)

        TextBox2.Name = "TextBox2"
        TextBox2.Location = New Point(15, 135)
        TextBox2.Size = New Size(220, 120)
        TextBox2.Multiline = True
        TextBox2.ScrollBars = ScrollBars.Both
        TextBox2.ReadOnly = True
        Me.Controls.Add(TextBox2)
        AddHandler TextBox2.TextChanged, AddressOf TextBox2_TextChanged

        TextBox3.Name = "TextBox3"
        TextBox3.Location = New Point(15, 10)
        TextBox3.Size = New Size(220, 120)
        TextBox3.Multiline = True
        TextBox3.ScrollBars = ScrollBars.Both
        TextBox3.ReadOnly = True
        Me.Controls.Add(TextBox3)

        Button1.Name = "Button1"
        Button1.Text = "執行"
        Button1.Location = New Point(380, 260)
        Me.Controls.Add(Button1)
        AddHandler Button1.Click, AddressOf Button1_Click

        Button2.Name = "Button2"
        Button2.Text = "上一題"
        Button2.Location = New Point(15, 260)
        Me.Controls.Add(Button2)
        AddHandler Button2.Click, AddressOf Button2_Click

        Button3.Name = "Button3"
        Button3.Text = "下一題"
        Button3.Location = New Point(160, 260)
        Me.Controls.Add(Button3)
        AddHandler Button3.Click, AddressOf Button3_Click

        Label1.Name = "Label1"
        Label1.Text = "程式碼:"
        Label1.Location = New Point(305, 10)
        Me.Controls.Add(Label1)

        ComboBox1.Name = "ComboBox1"
        ComboBox1.Location = New Point(105, 260)
        ComboBox1.Size = New Size(42, 20)
        Me.Controls.Add(ComboBox1)
        AddHandler ComboBox1.SelectedIndexChanged, AddressOf ComboBox1_SelectedIndexChanged

        CheckBox1.Name = "CheckBox1"
        CheckBox1.Location = New Point(470, 265)
        CheckBox1.Text = "逐步執行"
        CheckBox1.Checked = True
        Me.Controls.Add(CheckBox1)

        '題目
        Dim fullQuestion As String = ""
#Region "第一章"
        fullQuestion += "將A取代為B,BBBAAABA,BBBBBBBB,#本作中只有A=B 一道指令<br>#意思是用B 去取代A<br><br>#提示:程式會反覆執行<br>#直到找不到任何的A為止<br><br>A=B" + vbNewLine
        fullQuestion += "將A移到最前面,BACABBCAA,AAAABCBBC,BA=AB<br>CA=AC" + vbNewLine
        fullQuestion += "按照ABC的順序排列字串,BACABBCAA,AAAABBBCC," + vbNewLine
        fullQuestion += "將字母改成小寫,ABACCBA,abaccba," + vbNewLine
        fullQuestion += "消除全部的A,BAAACAABBCA,BCBBC,#提示:等號左邊留空白 = 刪除<br><br>A=" + vbNewLine
        fullQuestion += "合併連續出現的字母,BBAAACBCCCC,BACBC," + vbNewLine
        fullQuestion += "消除連續出現的A,BAAACBBCA,BCBBCA," + vbNewLine
        fullQuestion += "回傳出現次數最多的字母,AAABBABBAA,A," + vbNewLine
        fullQuestion += "回傳A的數量,AAAAAAAAAAAAA,13,#提示:十進位<br><br>A=1<br>1A=2<br>2A=3" + vbNewLine
#End Region
#Region "第二章"
        fullQuestion += "回傳Hello World,BBAAB,Hello world,#提示:關鍵字(return)<br>#代表直接回傳這個字串<br>#之後結束程式<br><br>=(return)Hello world" + vbNewLine
        fullQuestion += "若字串內包含一個以上A，回傳true，否則回傳false,ABBBAA,true,#提示:若找到A，則return true<br><br>A=(return)true" + vbNewLine
        fullQuestion += "若字串內包含三個以上A，回傳true，否則回傳false,ACBBAA,true," + vbNewLine
        fullQuestion += "若字串長度剛好等於三，回傳true，否則回傳false,ABC,true," + vbNewLine
        fullQuestion += "輸出字串長度除以三的餘數,AABC,1," + vbNewLine
        fullQuestion += "若字串中每個字母的數量為'0'或'奇數'，回傳true，否則回傳false,ABCCC,true," + vbNewLine
        fullQuestion += "若只有一個字母是單獨存在，回傳true，否則回傳false,AAABCCCBB,true," + vbNewLine
        fullQuestion += "若ABC字母的數量為C>B>A，回傳true，否則回傳false,ABBCCC,true," + vbNewLine
        fullQuestion += "回傳出現次數最多的字母,AAABCC,A," + vbNewLine
        fullQuestion += "回傳出現次數最少的字母,AAABCC,B," + vbNewLine
#End Region

        Dim fullQuestionArray() As String = Split(fullQuestion, vbNewLine)

        For i = 0 To fullQuestionArray.Length - 1
            Dim strTemp() As String = Split(fullQuestionArray(i), ",")
            If strTemp.Length < 4 Then
                Exit For
            End If
            question(i) = strTemp(0)
            input(i) = strTemp(1)
            output(i) = strTemp(2)
            example(i) = strTemp(3).Replace("<br>", vbNewLine)
            ComboBox1.Items.Add(i + 1)
        Next

        '額外input、output
        Dim exStr As String = ""
#Region "第一章"
        exStr += "BBBAAABA,BBBBBBBB" + vbNewLine '將A取代為B
        exStr += "BACABBCAA,AAAABCBBC" + vbNewLine '將A移到最前面
        exStr += "BACABBCAA,AAAABBBCC,CCCAAAACA,AAAAACCCC,BCACB,ABBCC" + vbNewLine '按照ABC的順序排列字串
        exStr += "ABACCBA,abaccba" + vbNewLine '將字母改成小寫
        exStr += "BAAACAABBCA,BCBBC" + vbNewLine '消除全部的A
        exStr += "BBAAACBCCCC,BACBC" + vbNewLine '合併連續出現的字母
        exStr += "BAAACBBCA,BCBBCA,BACAAAB,BACB,AAAAAAA,,AAAAAB,B,BAAAAC,BC" + vbNewLine '消除連續出現的A
        exStr += "AAABBABBAA,A,BAABBAABBAABA,A,BAABBBAAABBB,B" + vbNewLine '回傳出現次數最多的字母
        exStr += "AAAAAAAAAAAAA,13,AAAAA,5,AAAAAAAA,8,AAAAAAAAAAAAAAAAAA,18" + vbNewLine '回傳A的數量
#End Region
#Region "第二章"
        exStr += "BBAAB,Hello world" + vbNewLine '回傳Hello World
        exStr += "ABBCAA,true,BBCBB,false" + vbNewLine '若字串內包含一個以上A
        exStr += "ACBBAA,true,ABAACCA,true,BBBAAC,false,AABBACAA,true" + vbNewLine '若字串內包含三個以上A
        exStr += "ABC,true,AABBB,false,A,false,AACCBA,false" + vbNewLine '若字串長度剛好等於三
        exStr += "AABC,1,ACAAB,2,ABB,0,CCABB,2" + vbNewLine '輸出字串長度除以三的餘數
        exStr += "ABCCC,true,AABCC,false,ABCC,false,ABBCCC,false,AAAB,true" + vbNewLine '若字串中每個字母的數量為'0'或'奇數'
        exStr += "AAABCCCBB,true,ABCCC,false,AAABCCA,false,BBCCC,false" + vbNewLine '若只有一個字母是單獨存在
        exStr += "ABBCCC,true,BBCCA,false,CBCCCBA,true,AACBCC,false,CCCBB,true" + vbNewLine '若ABC字母的數量為C>B>A
        exStr += "AAABCC,A,BBABC,B,ABBCCC,C,CACBC,C" + vbNewLine '回傳出現次數最多的字母
        exStr += "AAABCC,B,CACBB,A,BBACA,C,CBBCCA,A" + vbNewLine '回傳出現次數最少的字母
#End Region

        Dim exStrArray() As String = Split(exStr, vbNewLine)

        For i = 0 To exStrArray.Length - 1
            Dim strTemp() As String = Split(exStrArray(i), ",")
            Dim exCount As Integer = 0
            If strTemp.Length < 2 Then
                Exit For
            End If
            For j = 0 To strTemp.Length - 1 Step 2
                exInput(i, exCount) = strTemp(j)
                exOutput(i, exCount) = strTemp(j + 1)
                exCount += 1
            Next
        Next

        num = 0
        setQuestion()
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs)
        Dim command() As String = TextBox1.Text.Split(vbCrLf) 'user輸入程式碼
        Dim outputTemp As String = input(num) '輸出結果暫存
        Dim exCount As Integer = 0 'exInputCount
        outputTemp = exInput(num, exCount)
        Dim timeOut As Integer = 0 '執行步驟上限
        Dim delayTime As Integer = 0 '控制逐步執行
        TextBox2.Text = ""

        If checkCommand() = False Then '偵測語法錯誤
            Exit Sub
        End If

        TextBox2.Text = "計算過程:" + vbNewLine
        TextBox2.Text += outputTemp + vbNewLine

        If CheckBox1.Checked Then lockButton() '按鈕鎖定

        Do
            Dim count As Integer = 0 '比對不符合的次數

            If CheckBox1.Checked Then
                delayTime = 1000
            Else
                delayTime = 0
            End If

            For i = 0 To command.Length - 1 '執行程式碼
                command(i) = command(i).Replace(vbCr, "").Replace(vbLf, "")
                Dim comTemp() As String = Split(command(i), "=")
                If comTemp.Length = 1 Then
                    count += 1
                    Continue For '跳過空行
                ElseIf Mid(comTemp(0), 1, 1) = "#" Then
                    count += 1
                    Continue For '跳過註解
                End If

                Dim flagLeft As String = "" '關鍵字
                Dim flagRight As String = ""

                If Mid(comTemp(0), 1, 6) = "(once)" Then '辨識關鍵字(左)
                    flagLeft = "once"
                    comTemp(0) = Mid(comTemp(0), 7, comTemp(0).Length - 1)
                End If

                If Mid(comTemp(1), 1, 8) = "(return)" Then '辨識關鍵字(右)
                    flagRight = "return"
                    comTemp(1) = Mid(comTemp(1), 9, comTemp(1).Length - 1)
                End If

                Dim comLeft As String = Trim(comTemp(0))
                Dim comRight As String = Trim(comTemp(1))

                Dim compare As Integer = InStr(outputTemp, comLeft)
                Dim outputLeft As String = ""
                Dim outputMid As String = ""
                Dim outputRight As String = ""

                If comLeft = "" Then
                    outputTemp = comRight + outputTemp
                    TextBox2.Text += "  -> " + command(i) + vbNewLine

                    If flagLeft = "once" Then '執行關鍵字(左)
                        command(i) = ""
                    End If

                    If flagRight = "return" Then '執行關鍵字(右)
                        outputTemp = comRight
                        count = command.Length
                    End If

                    TextBox2.Text += outputTemp + vbNewLine
                    Application.DoEvents()
                    Threading.Thread.Sleep(delayTime)

                    Exit For '執行成功，跳脫for迴圈
                ElseIf compare > 0 Then
                    outputLeft = Mid(outputTemp, 1, compare - 1)
                    outputMid = comRight
                    outputRight = Mid(outputTemp, compare + comLeft.Length, outputTemp.Length - 1)
                    outputTemp = outputLeft + outputMid + outputRight
                    TextBox2.Text += "  -> " + command(i) + vbNewLine

                    If flagLeft = "once" Then '執行關鍵字(左)
                        command(i) = ""
                    End If

                    If flagRight = "return" Then '執行關鍵字(右)
                        outputTemp = comRight
                        count = command.Length
                    End If

                    TextBox2.Text += outputTemp + vbNewLine
                    Application.DoEvents()
                    Threading.Thread.Sleep(delayTime)

                    Exit For '執行成功，跳脫for迴圈
                Else
                    count += 1 '比對不符合(此行程式碼未執行)
                End If
            Next

            If count = command.Length Then '此次比對全部不符合，開始對照答案
                If outputTemp = exOutput(num, exCount) Then
                    TextBox2.Text += "正確答案." + vbNewLine
                    exCount += 1 '答對，繼續執行下一組input
                    Application.DoEvents()
                    Threading.Thread.Sleep(delayTime / 2)

                    If exInput(num, exCount) <> "" Then '準備執行下一組input
                        outputTemp = exInput(num, exCount)
                        command = TextBox1.Text.Split(vbCrLf)
                        TextBox2.Text = "計算過程:" + vbNewLine
                        TextBox2.Text += outputTemp + vbNewLine
                    End If
                Else
                    TextBox2.Text += "錯誤答案." + vbNewLine
                    TextBox2.Text += "範例輸出:" + exOutput(num, exCount) + vbNewLine
                    TextBox2.Text += "目前輸出:" + outputTemp + vbNewLine
                    Exit Do '答錯，跳脫do迴圈
                End If
            End If

            timeOut += 1
            If timeOut >= 500 Then
                TextBox2.Text += "執行超時,強制中斷." + vbNewLine
                Exit Do
            ElseIf outputTemp.Length >= 200 Then
                TextBox2.Text += "輸出字串超出上限,強制中斷." + vbNewLine
                Exit Do
            End If
        Loop Until exInput(num, exCount) = "" 'input全數執行完畢，跳脫do迴圈

        If Button1.Enabled = False Then lockButton() '按鈕解鎖
    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs)
        num -= 1
        Button3.Enabled = True

        If num = 0 Then
            Button2.Enabled = False
        End If

        setQuestion()
    End Sub

    Private Sub Button3_Click(sender As Object, e As EventArgs)
        num += 1
        Button2.Enabled = True

        If question(num + 1) = "" Then
            Button3.Enabled = False
        End If

        setQuestion()
    End Sub

    Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs)
        num = ComboBox1.SelectedIndex

        Button2.Enabled = True
        Button3.Enabled = True

        If num = 0 Then
            Button2.Enabled = False
        ElseIf question(num + 1) = "" Then
            Button3.Enabled = False
        End If

        setQuestion()
    End Sub

    Sub setQuestion()
        TextBox3.Text = "第 " & (num + 1) & " 題:" + question(num) + vbNewLine +
            "範例輸入:" + input(num) + vbNewLine + "範例輸出:" + output(num)

        TextBox1.Text = example(num)
        TextBox2.Text = "計算過程:"
        ComboBox1.SelectedIndex = num
    End Sub
    Sub lockButton() '控制按鈕開關
        Button1.Enabled = Not Button1.Enabled
        If num > 0 Then
            Button2.Enabled = Not Button2.Enabled
        End If
        If question(num + 1) <> "" Then
            Button3.Enabled = Not Button3.Enabled
        End If
        ComboBox1.Enabled = Not ComboBox1.Enabled
        TextBox1.ReadOnly = Not TextBox1.ReadOnly
    End Sub

    Function checkCommand()
        Dim command() As String = TextBox1.Text.Split(vbCrLf)
        For i = 0 To command.Length - 1
            command(i) = command(i).Replace(vbCr, "").Replace(vbLf, "")
            Dim comTemp() As String = Split(command(i), "=")

            If Mid(comTemp(0), 1, 1) = "#" Then
                Continue For '跳過註解
            ElseIf command(i).Length = 0 Then
                Continue For '跳過空白行
            End If

            If comTemp.Length = 1 Then
                TextBox2.Text += "語法錯誤." + vbNewLine
                TextBox2.Text += "第 " & (i + 1) & " 行程式碼,沒有包含 = 符號" & vbNewLine
                Return False
            ElseIf comTemp.Length > 2 Then
                TextBox2.Text += "語法錯誤." + vbNewLine
                TextBox2.Text += "第 " & (i + 1) & " 行程式碼,包含2個以上的 = 符號" & vbNewLine
                Return False
            End If

            If Mid(comTemp(0), 1, 8) = "(return)" Then '辨識關鍵字(左)
                TextBox2.Text += "語法錯誤." + vbNewLine
                TextBox2.Text += "第 " & (i + 1) & " 行程式碼,(return)只能放在 = 的右邊" & vbNewLine
                Return False
            End If

            If Mid(comTemp(1), 1, 6) = "(once)" Then '辨識關鍵字(右)
                TextBox2.Text += "語法錯誤." + vbNewLine
                TextBox2.Text += "第 " & (i + 1) & " 行程式碼,(once)只能放在 = 的左邊" & vbNewLine
                Return False
            End If
        Next

        Return True
    End Function

    Private Sub TextBox2_TextChanged(sender As Object, e As EventArgs)
        TextBox2.SelectionStart = TextBox2.Text.Length '捲動TextBox到最下方
        TextBox2.ScrollToCaret()
    End Sub
End Class