Option Explicit On
Option Strict On

Public Class frmMainWindow

    Dim albumArray(1000) As String
    Dim albumCounter As Integer

    Private Sub btnQuit_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnQuit.Click

        Me.Close()

    End Sub

    Private Sub btnLoadList_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnLoadList.Click

        Dim listFile As IO.StreamReader
        Dim wishListFileName As String
        Dim fmtStr As String = "{0, -7}  {1, -30}"

        wishListFileName = InputBox("Enter the file path and name.", "Name of File", "WishList.txt")

        If wishListFileName = "" Then

            MessageBox.Show("You must enter a file name.  Please press the Load List button again.", "File Name Missing")

        Else

            If IO.File.Exists(wishListFileName) Then

                listFile = IO.File.OpenText(wishListFileName)

                Do While listFile.Peek <> -1

                    albumCounter += 1
                    albumArray(albumCounter) = listFile.ReadLine

                Loop

                listFile.Close()
                DisplayCDList()

                MessageBox.Show(albumCounter & " album(s) loaded from the list.", "Load Complete")
                btnDeleteCD.Enabled = True
                btnSortList.Enabled = True
                btnSaveList.Enabled = True
                btnLoadList.Enabled = False
                btnRandomCD.Enabled = True

            Else

                MessageBox.Show("There is no file with that path and filename.  Please press the Load List button again.", "File Not Found")

            End If

        End If

    End Sub

    Private Sub btnAddCD_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnAddCD.Click

        Dim fmtStr As String = "{0, -7}  {1, -30}"

        albumCounter += 1
        albumArray(albumCounter) = txtArtistName.Text & " - " & txtAlbumName.Text
        DisplayCDList()

        If albumCounter > 998 Then

            btnAddCD.Enabled = False
            MessageBox.Show("You have reached the limit.  If you want to add another album, you have to delete one first.", "Limit Reached")
            btnDeleteCD.Focus()

        End If

        btnDeleteCD.Enabled = True
        btnSortList.Enabled = True
        btnSaveList.Enabled = True
        btnRandomCD.Enabled = True
        txtArtistName.Clear()
        txtAlbumName.Clear()
        txtArtistName.Focus()

        ' This line will put set the focus to the last added cd.
        lstListOutput.SelectedIndex = albumCounter + 1

    End Sub

    Private Sub btnSaveList_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSaveList.Click

        Dim destinationFile As IO.StreamWriter
        Dim wishListFileName As String
        Dim stepLoop As Integer

        wishListFileName = InputBox("Enter the file path and name.", "Name of File", "WishList.txt")

        If wishListFileName = "" Then

            MessageBox.Show("You must enter a file name.  Please press the Load List button again.", "File Name Missing")

        ElseIf IO.File.Exists(wishListFileName) Then

            IO.File.Delete(wishListFileName)

        End If

        destinationFile = IO.File.AppendText(wishListFileName)

        For stepLoop = 1 To albumCounter

            destinationFile.WriteLine(albumArray(stepLoop))

        Next

        destinationFile.Close()

        If IO.File.Exists(wishListFileName) Then

            MessageBox.Show("Your data has been saved.", "File Saved")

        Else

            MessageBox.Show("The destination file does not exist.  Something went wrong.", "File Save Not Successful")

        End If

    End Sub

    Private Sub btnDeleteCD_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDeleteCD.Click

        Dim stepLoop As Long
        Dim selectedSpot As Long

        selectedSpot = lstListOutput.SelectedIndex - 1
        lstListOutput.Items.RemoveAt(lstListOutput.SelectedIndex)

        For stepLoop = selectedSpot To UBound(albumArray) - 1

            albumArray(CInt(stepLoop)) = albumArray(CInt(stepLoop + 1))

        Next

        ReDim Preserve albumArray(UBound(albumArray) - 1)
        albumCounter -= 1

    End Sub

    Private Sub btnSortList_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSortList.Click

        Dim sortGap As Integer
        Dim doneFlag As Boolean
        Dim tempHolder As String
        Dim stepLoop As Integer
        Dim fmtStr As String = "{0, -7}  {1, -30}"

        sortGap = CInt(Int(albumCounter / 2))

        Do While sortGap >= 1

            Do

                doneFlag = True

                For stepLoop = 1 To albumCounter - sortGap

                    If albumArray(stepLoop) > albumArray(stepLoop + sortGap) Then

                        tempHolder = albumArray(stepLoop)
                        albumArray(stepLoop) = albumArray(stepLoop + sortGap)
                        albumArray(stepLoop + sortGap) = tempHolder
                        doneFlag = False

                    End If

                Next

            Loop Until doneFlag = True

            sortGap = CInt(Int(sortGap / 2))

        Loop

        DisplayCDList()
        txtArtistName.Focus()

    End Sub

    Private Sub frmMainWindow_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        btnLoadList.Focus()

    End Sub

    Private Sub btnRandomCD_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnRandomCD.Click

        Dim randomNum As New Random
        Dim randomAlbum As Integer

        randomAlbum = randomNum.Next(1, albumCounter + 1)
        MessageBox.Show("Your randomly selected cd is " & albumArray(randomAlbum) & ".", "Random CD")

    End Sub

    Sub DisplayCDList()

        Dim stepLoop As Integer
        Dim fmtStr As String = "{0, -7}  {1, -30}"

        lstListOutput.Items.Clear()
        lstListOutput.Items.Add(String.Format(fmtStr, "Album #", "Artist - Album Name"))
        lstListOutput.Items.Add(String.Format(fmtStr, "-------", "-------------------"))

        For stepLoop = 1 To albumCounter

            lstListOutput.Items.Add(String.Format(fmtStr, stepLoop, albumArray(stepLoop)))

        Next

    End Sub

End Class