Visual Basic Memory Game

Public Class Form1
    Private cardValues() As String = {"🍎", "🍌", "🍇", "🍒", "🍎", "🍌", "🍇", "🍒"}
    Private buttons() As Button
    Private firstButton As Button = Nothing
    Private secondButton As Button = Nothing
    Private lockBoard As Boolean = False
    Private pairsFound As Integer = 0
    Private moves As Integer = 0

    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        buttons = {btn0, btn1, btn2, btn3, btn4, btn5, btn6, btn7}
        ShuffleCards()
        ResetGame()
    End Sub

    Private Sub ShuffleCards()
        Dim rnd As New Random()
        For i As Integer = cardValues.Length - 1 To 1 Step -1
            Dim j As Integer = rnd.Next(i + 1)
            Dim temp As String = cardValues(i)
            cardValues(i) = cardValues(j)
            cardValues(j) = temp
        Next
    End Sub

    Private Sub Card_Click(sender As Object, e As EventArgs) _
        Handles btn0.Click, btn1.Click, btn2.Click, btn3.Click,
                btn4.Click, btn5.Click, btn6.Click, btn7.Click

        If lockBoard Then Exit Sub

        Dim clickedButton As Button = CType(sender, Button)
        Dim index As Integer = Convert.ToInt32(clickedButton.Tag)

        If clickedButton.Text <> "?" Then Exit Sub

        clickedButton.Text = cardValues(index)

        If firstButton Is Nothing Then
            firstButton = clickedButton
            lblStatus.Text = "Select another card."
            Exit Sub
        End If

        secondButton = clickedButton
        moves += 1
        lblMoves.Text = moves.ToString()

        If firstButton.Text = secondButton.Text Then
            firstButton.Enabled = False
            secondButton.Enabled = False
            firstButton.BackColor = Color.LightGreen
            secondButton.BackColor = Color.LightGreen

            pairsFound += 1
            lblPairs.Text = pairsFound.ToString()
            lblStatus.Text = "✅ Match found!"

            firstButton = Nothing
            secondButton = Nothing

            If pairsFound = 4 Then
                lblStatus.Text = "🎉 Congratulations! You found all pairs."
                MessageBox.Show("You found all pairs!", "Memory Game")
            End If
        Else
            lockBoard = True
            lblStatus.Text = "❌ Not a match."
            Timer1.Interval = 800
            Timer1.Start()
        End If
    End Sub

    Private Sub Timer1_Tick(sender As Object, e As EventArgs) Handles Timer1.Tick
        Timer1.Stop()

        If firstButton IsNot Nothing Then firstButton.Text = "?"
        If secondButton IsNot Nothing Then secondButton.Text = "?"

        firstButton = Nothing
        secondButton = Nothing
        lockBoard = False

        lblStatus.Text = "Try again."
    End Sub

    Private Sub btnReset_Click(sender As Object, e As EventArgs) Handles btnReset.Click
        ShuffleCards()
        ResetGame()
    End Sub

    Private Sub ResetGame()
        For Each btn As Button In buttons
            btn.Text = "?"
            btn.Enabled = True
            btn.BackColor = SystemColors.Control
        Next

        firstButton = Nothing
        secondButton = Nothing
        lockBoard = False
        pairsFound = 0
        moves = 0

        lblPairs.Text = "0"
        lblMoves.Text = "0"
        lblStatus.Text = "Click a card to begin."
    End Sub
End Class