Imports System.IO
Imports System.Net.Sockets
Imports System.Reflection
Imports System.Security.Cryptography
Imports System.Text
Imports System.Text.Json
Imports System.Threading

Public Class Form1
    Private Const ConfigFileName As String = "moxa-okuma-settings.json"

    Private ReadOnly cboAzienda As New ComboBox()
    Private ReadOnly cboMacchina As New ComboBox()
    Private ReadOnly txtIpMoxa As New TextBox()
    Private ReadOnly nudPorta As New NumericUpDown()
    Private ReadOnly nudTimeoutConnessione As New NumericUpDown()
    Private ReadOnly nudTimeoutInattivita As New NumericUpDown()
    Private ReadOnly nudPausaRiga As New NumericUpDown()
    Private ReadOnly nudPausaCarattere As New NumericUpDown()
    Private ReadOnly nudDimensioneBlocco As New NumericUpDown()
    Private ReadOnly nudPausaBlocco As New NumericUpDown()
    Private ReadOnly nudAttesaPrimaInvio As New NumericUpDown()
    Private ReadOnly nudAttesaDopoInvio As New NumericUpDown()
    Private ReadOnly chkInvioRigaPerRiga As New CheckBox()
    Private ReadOnly chkInvioCaratterePerCarattere As New CheckBox()
    Private ReadOnly chkInvioBlocchi As New CheckBox()
    Private ReadOnly cboTerminatoreInvio As New ComboBox()
    Private ReadOnly txtFileInvio As New TextBox()
    Private ReadOnly txtFileRicezione As New TextBox()
    Private ReadOnly btnSfogliaInvio As New Button()
    Private ReadOnly btnSfogliaRicezione As New Button()
    Private ReadOnly btnTestConnessione As New Button()
    Private ReadOnly btnInvia As New Button()
    Private ReadOnly btnRicevi As New Button()
    Private ReadOnly btnAnnulla As New Button()
    Private ReadOnly mnuSblocca As New ToolStripMenuItem("Sblocca controlli")
    Private ReadOnly mnuCambiaPassword As New ToolStripMenuItem("Cambia password")
    Private ReadOnly mnuPulisciLog As New ToolStripMenuItem("Pulisci log")
    Private ReadOnly mnuInformazioni As New ToolStripMenuItem("Informazioni su")
    Private ReadOnly btnAggiornaStatoMoxa As New Button()
    Private ReadOnly chkMonitorStatoMoxa As New CheckBox()
    Private ReadOnly nudIntervalloStatoMoxa As New NumericUpDown()
    Private ReadOnly lstStatoMoxa As New ListView()
    Private ReadOnly imgStatoMoxa As New ImageList()
    Private ReadOnly statusTimer As New System.Windows.Forms.Timer()
    Private ReadOnly txtLog As New TextBox()
    Private ReadOnly progress As New ProgressBar()
    Private ReadOnly lockedControls As New List(Of Control)()

    Private appConfig As AppConfig
    Private cts As CancellationTokenSource
    Private controlsUnlocked As Boolean
    Private loadingSelection As Boolean
    Private checkingMoxaStatus As Boolean

    Public Sub New()
        InitializeComponent()
        appConfig = LoadOrCreateConfig()
        CleanupOldTemporaryReceives()
        BuildInterface()
        LoadCompanies()
        SetControlsUnlocked(False)
    End Sub

    Private Sub BuildInterface()
        Text = "LMEMoxaTransfer"
        Icon = New Icon(Path.Combine(Application.StartupPath, "Assets", "app-icon.ico"))
        MinimumSize = New Size(1030, 690)
        Size = New Size(1120, 760)
        StartPosition = FormStartPosition.CenterScreen

        Dim shell As New TableLayoutPanel With {
            .Dock = DockStyle.Fill,
            .ColumnCount = 1,
            .RowCount = 2,
            .Margin = Padding.Empty,
            .Padding = Padding.Empty
        }
        shell.RowStyles.Add(New RowStyle(SizeType.AutoSize))
        shell.RowStyles.Add(New RowStyle(SizeType.Percent, 100))
        Controls.Add(shell)

        Dim mainMenu = BuildMainMenu()
        MainMenuStrip = mainMenu
        mainMenu.Dock = DockStyle.Fill
        shell.Controls.Add(mainMenu, 0, 0)

        Dim tabs As New TabControl With {.Dock = DockStyle.Fill, .Margin = Padding.Empty}
        Dim tabTrasferimento As New TabPage("Trasferimento programmi")
        Dim tabStatoMoxa As New TabPage("Stato Moxa")
        tabs.TabPages.Add(tabTrasferimento)
        tabs.TabPages.Add(tabStatoMoxa)
        shell.Controls.Add(tabs, 0, 1)

        Dim root As New TableLayoutPanel With {
            .Dock = DockStyle.Fill,
            .ColumnCount = 1,
            .RowCount = 4,
            .Padding = New Padding(14)
        }
        root.RowStyles.Add(New RowStyle(SizeType.AutoSize))
        root.RowStyles.Add(New RowStyle(SizeType.AutoSize))
        root.RowStyles.Add(New RowStyle(SizeType.Percent, 100))
        root.RowStyles.Add(New RowStyle(SizeType.AutoSize))
        tabTrasferimento.Controls.Add(root)

        Dim grpConnessione As New GroupBox With {
            .Text = "Connessione Moxa",
            .Dock = DockStyle.Top,
            .AutoSize = True,
            .Padding = New Padding(12)
        }
        root.Controls.Add(grpConnessione, 0, 0)

        Dim conn As New TableLayoutPanel With {.Dock = DockStyle.Fill, .ColumnCount = 10, .AutoSize = True}
        conn.ColumnStyles.Add(New ColumnStyle(SizeType.AutoSize))
        conn.ColumnStyles.Add(New ColumnStyle(SizeType.Absolute, 150))
        conn.ColumnStyles.Add(New ColumnStyle(SizeType.AutoSize))
        conn.ColumnStyles.Add(New ColumnStyle(SizeType.Absolute, 230))
        conn.ColumnStyles.Add(New ColumnStyle(SizeType.AutoSize))
        conn.ColumnStyles.Add(New ColumnStyle(SizeType.Absolute, 135))
        conn.ColumnStyles.Add(New ColumnStyle(SizeType.AutoSize))
        conn.ColumnStyles.Add(New ColumnStyle(SizeType.Absolute, 90))
        conn.ColumnStyles.Add(New ColumnStyle(SizeType.AutoSize))
        conn.ColumnStyles.Add(New ColumnStyle(SizeType.Absolute, 90))
        grpConnessione.Controls.Add(conn)

        cboAzienda.DropDownStyle = ComboBoxStyle.DropDownList
        cboAzienda.Dock = DockStyle.Fill
        cboMacchina.DropDownStyle = ComboBoxStyle.DropDownList
        cboMacchina.Dock = DockStyle.Fill
        txtIpMoxa.Dock = DockStyle.Fill
        txtIpMoxa.ReadOnly = True
        nudPorta.Minimum = 1
        nudPorta.Maximum = 65535
        nudTimeoutConnessione.Minimum = 1
        nudTimeoutConnessione.Maximum = 120
        nudTimeoutInattivita.Minimum = 1
        nudTimeoutInattivita.Maximum = 120

        conn.Controls.Add(New Label With {.Text = "Azienda", .AutoSize = True, .Anchor = AnchorStyles.Left}, 0, 0)
        conn.Controls.Add(cboAzienda, 1, 0)
        conn.Controls.Add(New Label With {.Text = "Macchina", .AutoSize = True, .Anchor = AnchorStyles.Left, .Margin = New Padding(14, 0, 3, 0)}, 2, 0)
        conn.Controls.Add(cboMacchina, 3, 0)
        conn.Controls.Add(New Label With {.Text = "IP Moxa", .AutoSize = True, .Anchor = AnchorStyles.Left, .Margin = New Padding(14, 0, 3, 0)}, 4, 0)
        conn.Controls.Add(txtIpMoxa, 5, 0)
        conn.Controls.Add(New Label With {.Text = "Porta", .AutoSize = True, .Anchor = AnchorStyles.Left, .Margin = New Padding(14, 0, 3, 0)}, 6, 0)
        conn.Controls.Add(nudPorta, 7, 0)
        conn.Controls.Add(New Label With {.Text = "Timeout s", .AutoSize = True, .Anchor = AnchorStyles.Left, .Margin = New Padding(14, 0, 3, 0)}, 8, 0)
        conn.Controls.Add(nudTimeoutConnessione, 9, 0)

        Dim grpTrasferimento As New GroupBox With {
            .Text = "Invio e ricezione programmi",
            .Dock = DockStyle.Top,
            .AutoSize = True,
            .Padding = New Padding(12),
            .Margin = New Padding(0, 12, 0, 12)
        }
        root.Controls.Add(grpTrasferimento, 0, 1)

        Dim transfer As New TableLayoutPanel With {.Dock = DockStyle.Fill, .ColumnCount = 4, .RowCount = 10, .AutoSize = True}
        transfer.ColumnStyles.Add(New ColumnStyle(SizeType.AutoSize))
        transfer.ColumnStyles.Add(New ColumnStyle(SizeType.Percent, 100))
        transfer.ColumnStyles.Add(New ColumnStyle(SizeType.AutoSize))
        transfer.ColumnStyles.Add(New ColumnStyle(SizeType.Absolute, 120))
        grpTrasferimento.Controls.Add(transfer)

        ConfigureButton(btnSfogliaInvio, "Sfoglia")
        ConfigureButton(btnSfogliaRicezione, "Sfoglia")
        ConfigureButton(btnTestConnessione, "Test connessione")
        ConfigureButton(btnInvia, "Invia a Okuma")
        ConfigureButton(btnRicevi, "Ricevi da Okuma")
        ConfigureButton(btnAnnulla, "Annulla")
        btnAnnulla.Enabled = False

        txtFileInvio.Dock = DockStyle.Fill
        txtFileRicezione.Dock = DockStyle.Fill
        cboTerminatoreInvio.DropDownStyle = ComboBoxStyle.DropDownList
        cboTerminatoreInvio.Items.AddRange(New Object() {"Nessuno", "CR", "LF", "CRLF", "%", "% + CRLF"})
        chkInvioRigaPerRiga.Text = "Invio riga per riga"
        chkInvioRigaPerRiga.AutoSize = True
        chkInvioCaratterePerCarattere.Text = "Invio carattere per carattere"
        chkInvioCaratterePerCarattere.AutoSize = True
        chkInvioBlocchi.Text = "Invio a blocchi (% + CRLF)"
        chkInvioBlocchi.AutoSize = True
        ConfigureNumericDefaults()

        transfer.Controls.Add(New Label With {.Text = "File da inviare", .AutoSize = True, .Anchor = AnchorStyles.Left}, 0, 0)
        transfer.Controls.Add(txtFileInvio, 1, 0)
        transfer.Controls.Add(btnSfogliaInvio, 2, 0)
        transfer.Controls.Add(btnInvia, 3, 0)
        transfer.Controls.Add(New Label With {.Text = "Cartella ricezione", .AutoSize = True, .Anchor = AnchorStyles.Left}, 0, 1)
        transfer.Controls.Add(txtFileRicezione, 1, 1)
        transfer.Controls.Add(btnSfogliaRicezione, 2, 1)
        transfer.Controls.Add(btnRicevi, 3, 1)
        transfer.Controls.Add(New Label With {.Text = "Terminatore invio", .AutoSize = True, .Anchor = AnchorStyles.Left}, 0, 2)
        transfer.Controls.Add(cboTerminatoreInvio, 1, 2)
        transfer.Controls.Add(btnAnnulla, 3, 2)
        transfer.Controls.Add(New Label With {.Text = "Pausa riga ms", .AutoSize = True, .Anchor = AnchorStyles.Left}, 0, 3)
        transfer.Controls.Add(nudPausaRiga, 1, 3)
        transfer.Controls.Add(chkInvioRigaPerRiga, 2, 3)
        transfer.Controls.Add(New Label With {.Text = "Pausa carattere ms", .AutoSize = True, .Anchor = AnchorStyles.Left}, 0, 4)
        transfer.Controls.Add(nudPausaCarattere, 1, 4)
        transfer.Controls.Add(chkInvioCaratterePerCarattere, 2, 4)
        transfer.Controls.Add(New Label With {.Text = "Modo Okuma READ", .AutoSize = True, .Anchor = AnchorStyles.Left}, 0, 5)
        transfer.Controls.Add(chkInvioBlocchi, 1, 5)
        transfer.Controls.Add(New Label With {.Text = "Dim. blocco byte", .AutoSize = True, .Anchor = AnchorStyles.Left}, 2, 5)
        transfer.Controls.Add(nudDimensioneBlocco, 3, 5)
        transfer.Controls.Add(New Label With {.Text = "Pausa blocco ms", .AutoSize = True, .Anchor = AnchorStyles.Left}, 0, 6)
        transfer.Controls.Add(nudPausaBlocco, 1, 6)
        transfer.Controls.Add(New Label With {.Text = "Fine ricez. s", .AutoSize = True, .Anchor = AnchorStyles.Left}, 2, 6)
        transfer.Controls.Add(nudTimeoutInattivita, 3, 6)
        transfer.Controls.Add(New Label With {.Text = "Attesa prima invio s", .AutoSize = True, .Anchor = AnchorStyles.Left}, 0, 7)
        transfer.Controls.Add(nudAttesaPrimaInvio, 1, 7)
        transfer.Controls.Add(btnTestConnessione, 3, 7)
        transfer.Controls.Add(New Label With {.Text = "Attesa dopo invio s", .AutoSize = True, .Anchor = AnchorStyles.Left}, 0, 8)
        transfer.Controls.Add(nudAttesaDopoInvio, 1, 8)

        Dim hint As New Label With {
            .Text = "Prima di ricevere o inviare, selezionare azienda e macchina. I parametri Moxa vengono compilati dal file JSON nello start path.",
            .AutoSize = True,
            .Dock = DockStyle.Fill,
            .ForeColor = Color.FromArgb(70, 70, 70),
            .Margin = New Padding(0, 10, 0, 0)
        }
        transfer.SetColumnSpan(hint, 4)
        transfer.Controls.Add(hint, 0, 9)

        txtLog.Dock = DockStyle.Fill
        txtLog.Multiline = True
        txtLog.ScrollBars = ScrollBars.Vertical
        txtLog.ReadOnly = True
        txtLog.Font = New Font("Consolas", 10.0F)
        root.Controls.Add(txtLog, 0, 2)

        progress.Dock = DockStyle.Fill
        progress.Style = ProgressBarStyle.Blocks
        root.Controls.Add(progress, 0, 3)

        lockedControls.AddRange({nudPorta, nudTimeoutConnessione, nudTimeoutInattivita, cboTerminatoreInvio, nudPausaRiga, nudPausaCarattere, nudDimensioneBlocco, nudPausaBlocco, nudAttesaPrimaInvio, nudAttesaDopoInvio, chkInvioRigaPerRiga, chkInvioCaratterePerCarattere, chkInvioBlocchi})

        AddHandler cboAzienda.SelectedIndexChanged, AddressOf CompanyChanged
        AddHandler cboMacchina.SelectedIndexChanged, AddressOf MachineChanged
        AddHandler mnuSblocca.Click, AddressOf UnlockClicked
        AddHandler mnuCambiaPassword.Click, AddressOf ChangePasswordClicked
        AddHandler mnuPulisciLog.Click, AddressOf ClearLogClicked
        AddHandler mnuInformazioni.Click, AddressOf AboutClicked
        AddHandler btnSfogliaInvio.Click, AddressOf SelectInputFile
        AddHandler btnSfogliaRicezione.Click, AddressOf SelectOutputFile
        AddHandler btnTestConnessione.Click, AddressOf TestConnectionClicked
        AddHandler btnInvia.Click, AddressOf SendClicked
        AddHandler btnRicevi.Click, AddressOf ReceiveClicked
        AddHandler btnAnnulla.Click, Sub() cts?.Cancel()

        txtFileRicezione.Text = GetInitialReceiveDirectory()
        BuildStatusTab(tabStatoMoxa)
        Log($"Pronto. Configurazione: {ConfigPath()}")
    End Sub

    Private Function BuildMainMenu() As MenuStrip
        Dim menu As New MenuStrip()
        Dim strumenti As New ToolStripMenuItem("Strumenti")
        strumenti.DropDownItems.Add(mnuSblocca)
        strumenti.DropDownItems.Add(mnuCambiaPassword)
        strumenti.DropDownItems.Add(New ToolStripSeparator())
        strumenti.DropDownItems.Add(mnuPulisciLog)

        Dim aiuto As New ToolStripMenuItem("?")
        aiuto.DropDownItems.Add(mnuInformazioni)

        menu.Items.Add(strumenti)
        menu.Items.Add(aiuto)
        Return menu
    End Function

    Private Function GetInitialReceiveDirectory() As String
        If Not String.IsNullOrWhiteSpace(appConfig.LastReceiveDirectory) AndAlso Directory.Exists(appConfig.LastReceiveDirectory) Then
            Return appConfig.LastReceiveDirectory
        End If

        Return Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory)
    End Function

    Private Sub BuildStatusTab(tab As TabPage)
        Dim root As New TableLayoutPanel With {
            .Dock = DockStyle.Fill,
            .ColumnCount = 1,
            .RowCount = 2,
            .Padding = New Padding(14)
        }
        root.RowStyles.Add(New RowStyle(SizeType.AutoSize))
        root.RowStyles.Add(New RowStyle(SizeType.Percent, 100))
        tab.Controls.Add(root)

        Dim actions As New FlowLayoutPanel With {.Dock = DockStyle.Fill, .AutoSize = True, .FlowDirection = FlowDirection.LeftToRight}
        ConfigureButton(btnAggiornaStatoMoxa, "Aggiorna")
        chkMonitorStatoMoxa.Text = "Controllo automatico"
        chkMonitorStatoMoxa.AutoSize = True
        chkMonitorStatoMoxa.Checked = True
        chkMonitorStatoMoxa.Margin = New Padding(16, 8, 0, 3)
        nudIntervalloStatoMoxa.Minimum = 5
        nudIntervalloStatoMoxa.Maximum = 3600
        nudIntervalloStatoMoxa.Value = Math.Max(nudIntervalloStatoMoxa.Minimum, Math.Min(nudIntervalloStatoMoxa.Maximum, appConfig.MonitorRefreshSeconds))
        nudIntervalloStatoMoxa.Width = 80

        actions.Controls.Add(btnAggiornaStatoMoxa)
        actions.Controls.Add(chkMonitorStatoMoxa)
        actions.Controls.Add(New Label With {.Text = "Intervallo s", .AutoSize = True, .Margin = New Padding(16, 9, 3, 3)})
        actions.Controls.Add(nudIntervalloStatoMoxa)
        root.Controls.Add(actions, 0, 0)

        imgStatoMoxa.ImageSize = New Size(16, 16)
        imgStatoMoxa.ColorDepth = ColorDepth.Depth32Bit
        imgStatoMoxa.Images.Add("unknown", CreateStatusIcon(Color.Gray))
        imgStatoMoxa.Images.Add("online", CreateStatusIcon(Color.FromArgb(0, 150, 70)))
        imgStatoMoxa.Images.Add("offline", CreateStatusIcon(Color.FromArgb(210, 40, 40)))

        lstStatoMoxa.Dock = DockStyle.Fill
        lstStatoMoxa.View = View.Details
        lstStatoMoxa.FullRowSelect = True
        lstStatoMoxa.GridLines = True
        lstStatoMoxa.SmallImageList = imgStatoMoxa
        lstStatoMoxa.Columns.Add("Macchina", 280)
        lstStatoMoxa.Columns.Add("IP Moxa", 140)
        lstStatoMoxa.Columns.Add("Porta", 70)
        lstStatoMoxa.Columns.Add("Stato", 130)
        lstStatoMoxa.Columns.Add("Ultimo controllo", 160)
        lstStatoMoxa.Columns.Add("Note", 220)
        root.Controls.Add(lstStatoMoxa, 0, 1)

        lockedControls.Add(chkMonitorStatoMoxa)
        lockedControls.Add(nudIntervalloStatoMoxa)

        statusTimer.Interval = CInt(nudIntervalloStatoMoxa.Value) * 1000
        statusTimer.Enabled = chkMonitorStatoMoxa.Checked
        AddHandler btnAggiornaStatoMoxa.Click, AddressOf RefreshMoxaStatusClicked
        AddHandler statusTimer.Tick, AddressOf StatusTimerTick
        AddHandler nudIntervalloStatoMoxa.ValueChanged, AddressOf StatusIntervalChanged
        AddHandler chkMonitorStatoMoxa.CheckedChanged, AddressOf StatusMonitorChanged

        PopulateMoxaStatusList()
    End Sub

    Private Shared Function CreateStatusIcon(color As Color) As Bitmap
        Dim bitmap As New Bitmap(16, 16)
        Using g = Graphics.FromImage(bitmap)
            g.Clear(Color.Transparent)
            Using brush As New SolidBrush(color)
                g.FillEllipse(brush, 2, 2, 12, 12)
            End Using
            Using pen As New Pen(Color.FromArgb(80, 0, 0, 0))
                g.DrawEllipse(pen, 2, 2, 12, 12)
            End Using
        End Using
        Return bitmap
    End Function

    Private Sub ConfigureNumericDefaults()
        nudPorta.Minimum = 1
        nudPorta.Maximum = 65535
        nudTimeoutConnessione.Minimum = 1
        nudTimeoutConnessione.Maximum = 120
        nudTimeoutInattivita.Minimum = 1
        nudTimeoutInattivita.Maximum = 120
        nudPausaRiga.Minimum = 0
        nudPausaRiga.Maximum = 2000
        nudPausaCarattere.Minimum = 0
        nudPausaCarattere.Maximum = 200
        nudDimensioneBlocco.Minimum = 1
        nudDimensioneBlocco.Maximum = 1024
        nudPausaBlocco.Minimum = 0
        nudPausaBlocco.Maximum = 5000
        nudAttesaPrimaInvio.Minimum = 0
        nudAttesaPrimaInvio.Maximum = 60
        nudAttesaDopoInvio.Minimum = 0
        nudAttesaDopoInvio.Maximum = 30
    End Sub

    Private Sub LoadCompanies()
        loadingSelection = True
        cboAzienda.Items.Clear()
        For Each company In appConfig.Companies
            cboAzienda.Items.Add(company.Name)
        Next
        loadingSelection = False

        If cboAzienda.Items.Count > 0 Then
            Dim index = Math.Max(0, appConfig.Companies.FindIndex(Function(c) c.Name = appConfig.DefaultCompany))
            cboAzienda.SelectedIndex = index
        End If

        PopulateMoxaStatusList()
    End Sub

    Private Sub PopulateMoxaStatusList()
        If lstStatoMoxa.Columns.Count = 0 Then
            Return
        End If

        lstStatoMoxa.BeginUpdate()
        lstStatoMoxa.Items.Clear()
        lstStatoMoxa.Groups.Clear()

        For Each company In appConfig.Companies
            Dim group As New ListViewGroup(company.Name, HorizontalAlignment.Left)
            lstStatoMoxa.Groups.Add(group)

            For Each machine In company.Machines
                Dim item As New ListViewItem(machine.Name, "unknown") With {
                    .Group = group,
                    .Tag = New MoxaStatusTarget With {.Company = company.Name, .Machine = machine}
                }
                item.SubItems.Add(machine.IpMoxa)
                item.SubItems.Add(appConfig.DefaultSettings.Port.ToString())
                item.SubItems.Add("Non controllato")
                item.SubItems.Add("")
                item.SubItems.Add(machine.Note)
                lstStatoMoxa.Items.Add(item)
            Next
        Next

        lstStatoMoxa.EndUpdate()
    End Sub

    Private Sub CompanyChanged(sender As Object, e As EventArgs)
        If loadingSelection OrElse cboAzienda.SelectedIndex < 0 Then
            Return
        End If

        Dim company = CurrentCompany()
        loadingSelection = True
        cboMacchina.Items.Clear()
        For Each machine In company.Machines
            cboMacchina.Items.Add(machine.Name)
        Next
        loadingSelection = False

        If cboMacchina.Items.Count > 0 Then
            cboMacchina.SelectedIndex = 0
        End If
    End Sub

    Private Sub MachineChanged(sender As Object, e As EventArgs)
        If loadingSelection Then
            Return
        End If

        ApplyCurrentMachineSettings()
    End Sub

    Private Sub ApplyCurrentMachineSettings()
        Dim machine = CurrentMachine()
        If machine Is Nothing Then
            Return
        End If

        Dim defaults = appConfig.DefaultSettings
        txtIpMoxa.Text = machine.IpMoxa
        nudPorta.Value = defaults.Port
        nudTimeoutConnessione.Value = defaults.ConnectionTimeoutSeconds
        nudTimeoutInattivita.Value = defaults.ReceiveIdleTimeoutSeconds
        cboTerminatoreInvio.SelectedItem = defaults.SendTerminator
        nudPausaRiga.Value = defaults.LineDelayMs
        nudPausaCarattere.Value = defaults.CharDelayMs
        chkInvioRigaPerRiga.Checked = defaults.LinePaced
        chkInvioCaratterePerCarattere.Checked = defaults.CharPaced
        chkInvioBlocchi.Checked = defaults.BlockPaced
        nudDimensioneBlocco.Value = defaults.BlockSizeBytes
        nudPausaBlocco.Value = defaults.BlockDelayMs
        nudAttesaPrimaInvio.Value = defaults.WaitBeforeSendSeconds
        nudAttesaDopoInvio.Value = defaults.WaitAfterSendSeconds
        Log($"Macchina selezionata: {CurrentCompany().Name} / {machine.Name} - IP Moxa {machine.IpMoxa}.")
    End Sub

    Private Function CurrentCompany() As CompanyConfig
        If cboAzienda.SelectedIndex < 0 OrElse cboAzienda.SelectedIndex >= appConfig.Companies.Count Then
            Return Nothing
        End If
        Return appConfig.Companies(cboAzienda.SelectedIndex)
    End Function

    Private Function CurrentMachine() As MachineConfig
        Dim company = CurrentCompany()
        If company Is Nothing OrElse cboMacchina.SelectedIndex < 0 OrElse cboMacchina.SelectedIndex >= company.Machines.Count Then
            Return Nothing
        End If
        Return company.Machines(cboMacchina.SelectedIndex)
    End Function

    Private Sub UnlockClicked(sender As Object, e As EventArgs)
        If controlsUnlocked Then
            SetControlsUnlocked(False)
            Return
        End If

        If String.IsNullOrWhiteSpace(appConfig.AdminPasswordHash) OrElse String.IsNullOrWhiteSpace(appConfig.AdminPasswordSalt) Then
            Dim newPassword = PromptPassword("Password non configurata", "Inserire una nuova password amministratore:")
            If String.IsNullOrEmpty(newPassword) Then
                Return
            End If
            SetPassword(newPassword)
            SaveConfig()
            SetControlsUnlocked(True)
            Return
        End If

        Dim password = PromptPassword("Sblocca controlli", "Inserire la password:")
        If password Is Nothing Then
            Return
        End If

        If VerifyPassword(password) Then
            SetControlsUnlocked(True)
        Else
            MessageBox.Show(Me, "Password non corretta.", "Accesso negato", MessageBoxButtons.OK, MessageBoxIcon.Warning)
        End If
    End Sub

    Private Sub ChangePasswordClicked(sender As Object, e As EventArgs)
        If Not String.IsNullOrWhiteSpace(appConfig.AdminPasswordHash) AndAlso Not String.IsNullOrWhiteSpace(appConfig.AdminPasswordSalt) Then
            Dim oldPassword = PromptPassword("Cambia password", "Inserire la vecchia password:")
            If oldPassword Is Nothing Then
                Return
            End If
            If Not VerifyPassword(oldPassword) Then
                MessageBox.Show(Me, "Vecchia password non corretta.", "Password", MessageBoxButtons.OK, MessageBoxIcon.Warning)
                Return
            End If
        End If

        Dim newPassword = PromptPassword("Cambia password", "Inserire la nuova password:")
        If String.IsNullOrEmpty(newPassword) Then
            Return
        End If

        SetPassword(newPassword)
        SaveConfig()
        MessageBox.Show(Me, "Password aggiornata.", "Password", MessageBoxButtons.OK, MessageBoxIcon.Information)
    End Sub

    Private Sub ClearLogClicked(sender As Object, e As EventArgs)
        txtLog.Clear()
    End Sub

    Private Sub AboutClicked(sender As Object, e As EventArgs)
        Dim version = Assembly.GetExecutingAssembly().GetName().Version
        MessageBox.Show(Me,
                        $"LMEMoxaTransfer{Environment.NewLine}{Environment.NewLine}Azienda: Compomac SPA{Environment.NewLine}Autore: Livio Merola{Environment.NewLine}Versione: {version}",
                        "Informazioni su",
                        MessageBoxButtons.OK,
                        MessageBoxIcon.Information)
    End Sub

    Private Async Sub RefreshMoxaStatusClicked(sender As Object, e As EventArgs)
        Await RefreshMoxaStatusAsync()
    End Sub

    Private Async Sub StatusTimerTick(sender As Object, e As EventArgs)
        If chkMonitorStatoMoxa.Checked Then
            Await RefreshMoxaStatusAsync()
        End If
    End Sub

    Private Sub StatusIntervalChanged(sender As Object, e As EventArgs)
        statusTimer.Interval = CInt(nudIntervalloStatoMoxa.Value) * 1000
        appConfig.MonitorRefreshSeconds = CInt(nudIntervalloStatoMoxa.Value)
        SaveConfig()
    End Sub

    Private Sub StatusMonitorChanged(sender As Object, e As EventArgs)
        statusTimer.Enabled = chkMonitorStatoMoxa.Checked
    End Sub

    Private Async Function RefreshMoxaStatusAsync() As Task
        If checkingMoxaStatus Then
            Return
        End If

        checkingMoxaStatus = True
        btnAggiornaStatoMoxa.Enabled = False
        Try
            For Each item As ListViewItem In lstStatoMoxa.Items
                Dim target = TryCast(item.Tag, MoxaStatusTarget)
                If target Is Nothing Then
                    Continue For
                End If

                item.ImageKey = "unknown"
                item.SubItems(3).Text = "Controllo..."
                item.SubItems(4).Text = DateTime.Now.ToString("HH:mm:ss")
                Dim online = Await IsMoxaReachableAsync(target.Machine.IpMoxa, appConfig.DefaultSettings.Port, TimeSpan.FromMilliseconds(1200))
                item.ImageKey = If(online, "online", "offline")
                item.SubItems(3).Text = If(online, "Raggiungibile", "Non raggiungibile")
                item.SubItems(4).Text = DateTime.Now.ToString("HH:mm:ss")
            Next
        Finally
            btnAggiornaStatoMoxa.Enabled = True
            checkingMoxaStatus = False
        End Try
    End Function

    Private Shared Async Function IsMoxaReachableAsync(ip As String, port As Integer, timeout As TimeSpan) As Task(Of Boolean)
        If String.IsNullOrWhiteSpace(ip) Then
            Return False
        End If

        Using client As New TcpClient()
            Try
                Dim connectTask = client.ConnectAsync(ip.Trim(), port)
                Dim completed = Await Task.WhenAny(connectTask, Task.Delay(timeout))
                If completed IsNot connectTask Then
                    Return False
                End If
                Await connectTask
                Return True
            Catch
                Return False
            End Try
        End Using
    End Function

    Private Sub SetControlsUnlocked(unlocked As Boolean)
        controlsUnlocked = unlocked
        For Each control In lockedControls
            control.Enabled = unlocked
        Next
        mnuSblocca.Text = If(unlocked, "Blocca controlli", "Sblocca controlli")
    End Sub

    Private Async Sub TestConnectionClicked(sender As Object, e As EventArgs)
        Await RunTransferAsync(Async Function(token)
                                   Using client = Await ConnectAsync(token)
                                       Log("Test OK: connessione TCP aperta, nessun dato inviato a Okuma.")
                                   End Using
                               End Function)
    End Sub

    Private Shared Sub ConfigureButton(button As Button, text As String)
        button.Text = text
        button.AutoSize = True
        button.MinimumSize = New Size(110, 32)
        button.Margin = New Padding(8, 3, 0, 3)
    End Sub

    Private Sub SelectInputFile(sender As Object, e As EventArgs)
        Using dlg As New OpenFileDialog()
            dlg.Title = "Seleziona programma da inviare a Okuma"
            dlg.Filter = "Programmi CNC|*.min;*.eia;*.iso;*.txt;*.nc|Tutti i file|*.*"
            If dlg.ShowDialog(Me) = DialogResult.OK Then
                txtFileInvio.Text = dlg.FileName
            End If
        End Using
    End Sub

    Private Sub SelectOutputFile(sender As Object, e As EventArgs)
        Using dlg As New FolderBrowserDialog()
            dlg.Description = "Scegli la cartella dove salvare il programma ricevuto"
            dlg.UseDescriptionForTitle = True
            If Directory.Exists(txtFileRicezione.Text) Then
                dlg.SelectedPath = txtFileRicezione.Text
            End If
            If dlg.ShowDialog(Me) = DialogResult.OK Then
                txtFileRicezione.Text = dlg.SelectedPath
                appConfig.LastReceiveDirectory = dlg.SelectedPath
                SaveConfig()
            End If
        End Using
    End Sub

    Private Async Sub SendClicked(sender As Object, e As EventArgs)
        If CurrentMachine() Is Nothing Then
            MessageBox.Show(Me, "Selezionare azienda e macchina.", "Macchina mancante", MessageBoxButtons.OK, MessageBoxIcon.Warning)
            Return
        End If
        If Not File.Exists(txtFileInvio.Text) Then
            MessageBox.Show(Me, "Selezionare un file esistente da inviare.", "File mancante", MessageBoxButtons.OK, MessageBoxIcon.Warning)
            Return
        End If

        Await RunTransferAsync(Async Function(token)
                                   Dim fileBytes = Await File.ReadAllBytesAsync(txtFileInvio.Text, token)
                                   fileBytes = RemoveUtf8BomIfPresent(fileBytes)
                                   LogFirstBytes(fileBytes)
                                   LogNonStandardCncBytes(fileBytes)
                                   Dim blockPaced = chkInvioBlocchi.Checked
                                   Dim terminator = If(blockPaced, Encoding.ASCII.GetBytes("%" & vbCrLf), GetTerminatorBytes())

                                   Using client = Await ConnectAsync(token)
                                       Using stream = client.GetStream()
                                           Dim waitBeforeSend = CInt(nudAttesaPrimaInvio.Value)
                                           If waitBeforeSend > 0 Then
                                               Log($"Attesa prima del primo byte: {waitBeforeSend} s.")
                                               Await Task.Delay(TimeSpan.FromSeconds(waitBeforeSend), token)
                                           End If

                                           If blockPaced Then
                                               Dim blockSize = CInt(nudDimensioneBlocco.Value)
                                               Dim blockDelayMs = CInt(nudPausaBlocco.Value)
                                               Log($"Invio Okuma READ: blocchi da {blockSize} byte con pausa {blockDelayMs} ms.")
                                               Await SendBlockPacedAsync(stream, fileBytes, blockSize, blockDelayMs, token)
                                           ElseIf chkInvioRigaPerRiga.Checked Then
                                               Await SendLinePacedAsync(stream, fileBytes, CInt(nudPausaRiga.Value), CInt(nudPausaCarattere.Value), chkInvioCaratterePerCarattere.Checked, token)
                                           Else
                                               Await stream.WriteAsync(fileBytes, token)
                                           End If

                                           If terminator.Length > 0 Then
                                               Await stream.WriteAsync(terminator, token)
                                           End If
                                           Await stream.FlushAsync(token)

                                           Dim waitAfterSend = CInt(nudAttesaDopoInvio.Value)
                                           If blockPaced Then
                                               waitAfterSend = Math.Max(waitAfterSend, 1)
                                           End If
                                           If waitAfterSend > 0 Then
                                               Await Task.Delay(TimeSpan.FromSeconds(waitAfterSend), token)
                                           End If
                                       End Using
                                   End Using
                                   Log($"Inviati {fileBytes.Length:N0} byte a Okuma.")
                               End Function)
    End Sub

    Private Async Sub ReceiveClicked(sender As Object, e As EventArgs)
        If CurrentMachine() Is Nothing Then
            MessageBox.Show(Me, "Selezionare azienda e macchina.", "Macchina mancante", MessageBoxButtons.OK, MessageBoxIcon.Warning)
            Return
        End If
        If String.IsNullOrWhiteSpace(txtFileRicezione.Text) Then
            MessageBox.Show(Me, "Scegliere una cartella di destinazione per la ricezione.", "Cartella mancante", MessageBoxButtons.OK, MessageBoxIcon.Warning)
            Return
        End If

        Await RunTransferAsync(Async Function(token)
                                   Dim destinationDirectory = Path.GetFullPath(txtFileRicezione.Text)
                                   Directory.CreateDirectory(destinationDirectory)
                                   Dim temporaryPath = CreateTemporaryReceivePath()
                                   Using client = Await ConnectAsync(token)
                                       Using stream = client.GetStream()
                                           Dim received = Await ReceiveUntilIdleAsync(stream, temporaryPath, token)
                                           Log($"Ricevuti {received:N0} byte da Okuma.")
                                       End Using
                                   End Using
                                   Dim finalPath = PromptAndSaveReceivedFile(temporaryPath, destinationDirectory)
                                   Log($"File ricevuto salvato in: {finalPath}")
                               End Function)
    End Sub

    Private Async Function RunTransferAsync(action As Func(Of CancellationToken, Task)) As Task
        SetBusy(True)
        cts = New CancellationTokenSource()

        Try
            Await action(cts.Token)
            Log("Operazione completata.")
        Catch ex As OperationCanceledException
            Log("Operazione annullata.")
        Catch ex As Exception
            Log("Errore: " & ex.Message)
            MessageBox.Show(Me, ex.Message, "Errore trasferimento", MessageBoxButtons.OK, MessageBoxIcon.Error)
        Finally
            cts.Dispose()
            cts = Nothing
            SetBusy(False)
        End Try
    End Function

    Private Shared Async Function SendLinePacedAsync(stream As NetworkStream, data As Byte(), lineDelayMs As Integer, charDelayMs As Integer, charPaced As Boolean, token As CancellationToken) As Task
        Dim start = 0
        For i = 0 To data.Length - 1
            If data(i) = 10 Then
                Await WriteChunkAsync(stream, data, start, i - start + 1, charDelayMs, charPaced, token)
                Await stream.FlushAsync(token)
                start = i + 1
                If lineDelayMs > 0 Then
                    Await Task.Delay(lineDelayMs, token)
                End If
            End If
        Next
        If start < data.Length Then
            Await WriteChunkAsync(stream, data, start, data.Length - start, charDelayMs, charPaced, token)
        End If
    End Function

    Private Shared Async Function WriteChunkAsync(stream As NetworkStream, data As Byte(), offset As Integer, count As Integer, charDelayMs As Integer, charPaced As Boolean, token As CancellationToken) As Task
        If Not charPaced Then
            Await stream.WriteAsync(data.AsMemory(offset, count), token)
            Return
        End If

        For i = offset To offset + count - 1
            Await stream.WriteAsync(data.AsMemory(i, 1), token)
            If charDelayMs > 0 Then
                Await Task.Delay(charDelayMs, token)
            End If
        Next
    End Function

    Private Shared Async Function SendBlockPacedAsync(stream As NetworkStream, data As Byte(), blockSize As Integer, blockDelayMs As Integer, token As CancellationToken) As Task
        Dim offset = 0
        While offset < data.Length
            Dim count = Math.Min(blockSize, data.Length - offset)
            Await stream.WriteAsync(data.AsMemory(offset, count), token)
            Await stream.FlushAsync(token)
            offset += count
            If offset < data.Length AndAlso blockDelayMs > 0 Then
                Await Task.Delay(blockDelayMs, token)
            End If
        End While
    End Function

    Private Async Function ConnectAsync(token As CancellationToken) As Task(Of TcpClient)
        Dim machine = CurrentMachine()
        If machine Is Nothing Then
            Throw New InvalidOperationException("Macchina non selezionata.")
        End If

        Dim ip = machine.IpMoxa.Trim()
        Dim port = CInt(nudPorta.Value)
        Dim timeout = TimeSpan.FromSeconds(CInt(nudTimeoutConnessione.Value))
        Dim client As New TcpClient With {.NoDelay = True}

        Log($"Connessione a {ip}:{port}...")
        Dim connectTask = client.ConnectAsync(ip, port, token).AsTask()
        Dim completed = Await Task.WhenAny(connectTask, Task.Delay(timeout, token))
        If completed IsNot connectTask Then
            client.Dispose()
            Throw New TimeoutException($"Connessione non riuscita entro {timeout.TotalSeconds:N0} secondi.")
        End If

        Await connectTask
        Log("Connessione aperta.")
        Return client
    End Function

    Private Async Function ReceiveUntilIdleAsync(stream As NetworkStream, destinationPath As String, token As CancellationToken) As Task(Of Long)
        Dim buffer(8191) As Byte
        Dim total As Long = 0
        Dim idleTimeout = TimeSpan.FromSeconds(CInt(nudTimeoutInattivita.Value))

        Log("In attesa dati. Avviare l'invio programma dal controllo Okuma.")
        Using output As New FileStream(destinationPath, FileMode.Create, FileAccess.Write, FileShare.Read, 8192, useAsync:=True)
            Do
                Dim readTask = stream.ReadAsync(buffer.AsMemory(0, buffer.Length), token).AsTask()
                Dim completed = Await Task.WhenAny(readTask, Task.Delay(idleTimeout, token))

                If completed IsNot readTask Then
                    If total = 0 Then
                        Throw New TimeoutException("Nessun dato ricevuto prima del timeout di inattivita.")
                    End If
                    Exit Do
                End If

                Dim count = Await readTask
                If count = 0 Then
                    Exit Do
                End If

                Await output.WriteAsync(buffer.AsMemory(0, count), token)
                total += count
                progress.Value = CInt(Math.Min(progress.Maximum, total Mod progress.Maximum))
                Log($"Ricevuti {total:N0} byte...")
            Loop
        End Using

        Return total
    End Function

    Private Shared Function CreateTemporaryReceivePath() As String
        Dim tempDirectory = Path.Combine(Application.StartupPath, "RicezioniTemp")
        Directory.CreateDirectory(tempDirectory)
        Return Path.Combine(tempDirectory, $"ricezione_okuma_{DateTime.Now:yyyyMMdd_HHmmss}_{Guid.NewGuid():N}.tmp")
    End Function

    Private Shared Sub CleanupOldTemporaryReceives()
        Dim tempDirectory = Path.Combine(Application.StartupPath, "RicezioniTemp")
        If Not Directory.Exists(tempDirectory) Then
            Return
        End If

        For Each filePath In Directory.EnumerateFiles(tempDirectory, "*.tmp")
            Try
                If File.GetLastWriteTime(filePath) < DateTime.Now.AddDays(-7) Then
                    File.Delete(filePath)
                End If
            Catch
            End Try
        Next
    End Sub

    Private Function PromptAndSaveReceivedFile(temporaryPath As String, destinationDirectory As String) As String
        If Not File.Exists(temporaryPath) Then
            Return temporaryPath
        End If

        Dim suggestedName = ExtractProgramFileName(File.ReadAllBytes(temporaryPath))
        If String.IsNullOrWhiteSpace(suggestedName) Then
            suggestedName = "programma_okuma.min"
            Log("Nessun nome programma preceduto da $ trovato nel file ricevuto: propongo un nome predefinito.")
        End If

        Dim chosenName As String = Nothing
        Do
            chosenName = PromptReceivedFileName(suggestedName)
            If chosenName Is Nothing Then
                Log($"Nome finale annullato: il file temporaneo resta in {temporaryPath}")
                Return temporaryPath
            End If

            chosenName = Path.GetFileName(chosenName.Trim())
            If Not String.IsNullOrWhiteSpace(chosenName) AndAlso chosenName.IndexOfAny(Path.GetInvalidFileNameChars()) < 0 Then
                Exit Do
            End If

            MessageBox.Show(Me, "Nome file non valido.", "Nome file", MessageBoxButtons.OK, MessageBoxIcon.Warning)
        Loop

        Dim finalPath = Path.Combine(destinationDirectory, chosenName)

        If File.Exists(finalPath) Then
            Dim overwrite = MessageBox.Show(Me, $"Il file {chosenName} esiste gia'. Sovrascriverlo?", "File esistente", MessageBoxButtons.YesNo, MessageBoxIcon.Question)
            If overwrite <> DialogResult.Yes Then
                Return PromptAndSaveReceivedFile(temporaryPath, destinationDirectory)
            End If
        End If

        File.Move(temporaryPath, finalPath, True)
        Return finalPath
    End Function

    Private Shared Function ExtractProgramFileName(data As Byte()) As String
        Dim invalidChars = Path.GetInvalidFileNameChars()

        For i = 0 To data.Length - 1
            If data(i) <> AscW("$"c) Then
                Continue For
            End If

            Dim builder As New StringBuilder()
            For j = i + 1 To data.Length - 1
                Dim value = data(j)
                If value = 0 OrElse value = &HD OrElse value = &HA OrElse value = &H9 OrElse value = AscW("$"c) Then
                    Exit For
                End If
                If value < &H20 OrElse value > &H7E Then
                    Exit For
                End If

                Dim ch = ChrW(value)
                If Array.IndexOf(invalidChars, ch) >= 0 Then
                    Exit For
                End If

                builder.Append(ch)
            Next

            Dim candidate = builder.ToString().Trim()
            If candidate.Length > 0 AndAlso candidate.Contains("."c) Then
                Return candidate
            End If
        Next

        Return ""
    End Function

    Private Function PromptReceivedFileName(suggestedName As String) As String
        Using form As New Form With {.Text = "Nome file ricevuto", .StartPosition = FormStartPosition.CenterParent, .FormBorderStyle = FormBorderStyle.FixedDialog, .MinimizeBox = False, .MaximizeBox = False, .ClientSize = New Size(440, 140)}
            Dim label As New Label With {.Text = "Conferma o modifica il nome file da salvare:", .Left = 12, .Top = 12, .Width = 410, .AutoSize = False}
            Dim textBox As New TextBox With {.Left = 12, .Top = 42, .Width = 410, .Text = suggestedName}
            Dim ok As New Button With {.Text = "Salva", .Left = 256, .Top = 88, .Width = 78, .DialogResult = DialogResult.OK}
            Dim cancel As New Button With {.Text = "Annulla", .Left = 344, .Top = 88, .Width = 78, .DialogResult = DialogResult.Cancel}
            form.Controls.AddRange({label, textBox, ok, cancel})
            form.AcceptButton = ok
            form.CancelButton = cancel
            textBox.SelectAll()

            If form.ShowDialog(Me) = DialogResult.OK Then
                Return textBox.Text
            End If
        End Using

        Return Nothing
    End Function

    Private Function GetTerminatorBytes() As Byte()
        Select Case CStr(cboTerminatoreInvio.SelectedItem)
            Case "CR"
                Return Encoding.ASCII.GetBytes(vbCr)
            Case "LF"
                Return Encoding.ASCII.GetBytes(vbLf)
            Case "CRLF"
                Return Encoding.ASCII.GetBytes(vbCrLf)
            Case "%"
                Return Encoding.ASCII.GetBytes("%")
            Case "% + CRLF"
                Return Encoding.ASCII.GetBytes("%" & vbCrLf)
            Case Else
                Return Array.Empty(Of Byte)()
        End Select
    End Function

    Private Shared Function RemoveUtf8BomIfPresent(data As Byte()) As Byte()
        If data.Length < 3 OrElse data(0) <> &HEF OrElse data(1) <> &HBB OrElse data(2) <> &HBF Then
            Return data
        End If

        Dim cleanLength = data.Length - 3
        If cleanLength = 0 Then
            Return Array.Empty(Of Byte)()
        End If

        Dim clean(cleanLength - 1) As Byte
        Buffer.BlockCopy(data, 3, clean, 0, clean.Length)
        Return clean
    End Function

    Private Sub LogFirstBytes(data As Byte())
        If data.Length = 0 Then
            Log("File vuoto: nessun byte da inviare prima del terminatore.")
            Return
        End If

        Dim previewLength = Math.Min(16, data.Length)
        Dim preview As New StringBuilder()
        For i = 0 To previewLength - 1
            If i > 0 Then
                preview.Append(" ")
            End If
            preview.Append(data(i).ToString("X2"))
        Next

        Log($"Primi byte inviati: {preview}")
        If data(0) > &H7F Then
            Log($"Attenzione: il primo byte e' > 7 bit ({data(0):X2}). Per Okuma 7E1 puo' essere un carattere non valido.")
        End If
    End Sub

    Private Sub LogNonStandardCncBytes(data As Byte())
        Dim firstInvalidPosition As Integer = -1
        Dim firstInvalidValue As Byte = 0
        Dim invalidCount As Integer

        For i = 0 To data.Length - 1
            Dim value = data(i)
            Dim isAllowedControl = value = &H9 OrElse value = &HA OrElse value = &HD
            Dim isPrintableAscii = value >= &H20 AndAlso value <= &H7E
            If Not isAllowedControl AndAlso Not isPrintableAscii Then
                invalidCount += 1
                If firstInvalidPosition < 0 Then
                    firstInvalidPosition = i
                    firstInvalidValue = value
                End If
            End If
        Next

        If invalidCount > 0 Then
            Log($"Avviso: trovati {invalidCount} byte di controllo/non ASCII. Primo valore 0x{firstInvalidValue:X2} alla posizione {firstInvalidPosition}. Invio comunque.")
        End If
    End Sub

    Private Sub SetBusy(isBusy As Boolean)
        btnInvia.Enabled = Not isBusy
        btnRicevi.Enabled = Not isBusy
        btnTestConnessione.Enabled = Not isBusy
        btnSfogliaInvio.Enabled = Not isBusy
        btnSfogliaRicezione.Enabled = Not isBusy
        mnuSblocca.Enabled = Not isBusy
        mnuCambiaPassword.Enabled = Not isBusy
        mnuPulisciLog.Enabled = Not isBusy
        btnAnnulla.Enabled = isBusy
        If Not isBusy Then
            For Each control In lockedControls
                control.Enabled = controlsUnlocked
            Next
        Else
            For Each control In lockedControls
                control.Enabled = False
            Next
        End If
        progress.Style = If(isBusy, ProgressBarStyle.Marquee, ProgressBarStyle.Blocks)
        If Not isBusy Then
            progress.Value = 0
        End If
    End Sub

    Private Sub Log(message As String)
        If InvokeRequired Then
            BeginInvoke(Sub() Log(message))
            Return
        End If
        txtLog.AppendText($"{DateTime.Now:HH:mm:ss}  {message}{Environment.NewLine}")
    End Sub

    Private Shared Function ConfigPath() As String
        Return Path.Combine(Application.StartupPath, ConfigFileName)
    End Function

    Private Function LoadOrCreateConfig() As AppConfig
        Dim path = ConfigPath()
        If File.Exists(path) Then
            Dim loaded = JsonSerializer.Deserialize(Of AppConfig)(File.ReadAllText(path), JsonOptions())
            If loaded IsNot Nothing Then
                Return loaded
            End If
        End If

        Dim created = CreateDefaultConfig()
        appConfig = created
        SetPassword("moxa")
        SaveConfig()
        Return appConfig
    End Function

    Private Sub SaveConfig()
        File.WriteAllText(ConfigPath(), JsonSerializer.Serialize(appConfig, JsonOptions()))
    End Sub

    Private Shared Function JsonOptions() As JsonSerializerOptions
        Return New JsonSerializerOptions With {.WriteIndented = True, .PropertyNameCaseInsensitive = True}
    End Function

    Private Function VerifyPassword(password As String) As Boolean
        Dim salt = Convert.FromBase64String(appConfig.AdminPasswordSalt)
        Dim expected = Convert.FromBase64String(appConfig.AdminPasswordHash)
        Using pbkdf2 As New Rfc2898DeriveBytes(password, salt, 100000, HashAlgorithmName.SHA256)
            Dim actual = pbkdf2.GetBytes(expected.Length)
            Return CryptographicOperations.FixedTimeEquals(actual, expected)
        End Using
    End Function

    Private Sub SetPassword(password As String)
        Dim salt(15) As Byte
        RandomNumberGenerator.Fill(salt)
        Using pbkdf2 As New Rfc2898DeriveBytes(password, salt, 100000, HashAlgorithmName.SHA256)
            appConfig.AdminPasswordSalt = Convert.ToBase64String(salt)
            appConfig.AdminPasswordHash = Convert.ToBase64String(pbkdf2.GetBytes(32))
        End Using
    End Sub

    Private Function PromptPassword(title As String, prompt As String) As String
        Using form As New Form With {.Text = title, .StartPosition = FormStartPosition.CenterParent, .FormBorderStyle = FormBorderStyle.FixedDialog, .MinimizeBox = False, .MaximizeBox = False, .ClientSize = New Size(360, 130)}
            Dim label As New Label With {.Text = prompt, .Left = 12, .Top = 12, .Width = 330, .AutoSize = False}
            Dim textBox As New TextBox With {.Left = 12, .Top = 42, .Width = 330, .UseSystemPasswordChar = True}
            Dim ok As New Button With {.Text = "OK", .Left = 176, .Top = 84, .Width = 78, .DialogResult = DialogResult.OK}
            Dim cancel As New Button With {.Text = "Annulla", .Left = 264, .Top = 84, .Width = 78, .DialogResult = DialogResult.Cancel}
            form.Controls.AddRange({label, textBox, ok, cancel})
            form.AcceptButton = ok
            form.CancelButton = cancel
            If form.ShowDialog(Me) = DialogResult.OK Then
                Return textBox.Text
            End If
        End Using
        Return Nothing
    End Function

    Private Shared Function CreateDefaultConfig() As AppConfig
        Return New AppConfig With {
            .DefaultCompany = "SECUREX",
            .MonitorRefreshSeconds = 30,
            .DefaultSettings = New TransferSettings With {
                .Port = 10001,
                .ConnectionTimeoutSeconds = 10,
                .ReceiveIdleTimeoutSeconds = 15,
                .SendTerminator = "%",
                .LineDelayMs = 100,
                .CharDelayMs = 10,
                .LinePaced = True,
                .CharPaced = False,
                .BlockPaced = False,
                .BlockSizeBytes = 32,
                .BlockDelayMs = 100,
                .WaitBeforeSendSeconds = 2,
                .WaitAfterSendSeconds = 2
            },
            .Companies = New List(Of CompanyConfig) From {
                New CompanyConfig With {.Name = "SECUREX", .Machines = New List(Of MachineConfig) From {
                    New MachineConfig With {.Name = "M4 - N2LB 300", .IpMoxa = "192.168.0.101", .IpMachineWise = "192.168.0.214", .Note = "OSP-U100L"},
                    New MachineConfig With {.Name = "M5 - N3LB 300", .IpMoxa = "192.168.0.146", .IpMachineWise = "192.168.0.47", .Note = "OSP-E100L"},
                    New MachineConfig With {.Name = "M8 - CENTRO OKUMA", .IpMoxa = "192.168.0.113", .IpMachineWise = "192.168.0.68", .Note = "OSP-P200M"},
                    New MachineConfig With {.Name = "M11 - TORNIO OKUMA LB25I-N", .IpMoxa = "192.168.0.88", .IpMachineWise = "192.168.0.223"},
                    New MachineConfig With {.Name = "M12 - TORNIO OKUMA LB 400", .IpMoxa = "192.168.0.99", .IpMachineWise = "192.168.0.66"}
                }},
                New CompanyConfig With {.Name = "EMILIA", .Machines = New List(Of MachineConfig) From {
                    New MachineConfig With {.Name = "M1", .IpMoxa = "192.168.30.8", .IpMachineWise = "192.168.30.221"},
                    New MachineConfig With {.Name = "M2", .IpMoxa = "192.168.30.9", .IpMachineWise = "192.168.30.222"},
                    New MachineConfig With {.Name = "M3", .IpMoxa = "192.168.30.10", .IpMachineWise = "192.168.30.223"},
                    New MachineConfig With {.Name = "M4 - CENTRO LAVORO OKUMA", .IpMoxa = "192.168.30.11", .IpMachineWise = "192.168.30.224"},
                    New MachineConfig With {.Name = "M5", .IpMoxa = "192.168.30.12", .IpMachineWise = "192.168.30.225"},
                    New MachineConfig With {.Name = "M6", .IpMoxa = "192.168.30.13", .IpMachineWise = "192.168.30.226"}
                }},
                New CompanyConfig With {.Name = "SMART", .Machines = New List(Of MachineConfig) From {
                    New MachineConfig With {.Name = "M1", .IpMoxa = "192.168.35.10", .IpMachineWise = "192.168.35.212"},
                    New MachineConfig With {.Name = "M2", .IpMoxa = "192.168.35.11", .IpMachineWise = "192.168.35.211"},
                    New MachineConfig With {.Name = "M3", .IpMoxa = "192.168.35.12", .IpMachineWise = "192.168.35.213"},
                    New MachineConfig With {.Name = "M4 - CENTRO LAVORO OKUMA", .IpMoxa = "192.168.35.13", .IpMachineWise = "192.168.35.214"}
                }}
            }
        }
    End Function
End Class

Public Class AppConfig
    Public Property AdminPasswordHash As String = ""
    Public Property AdminPasswordSalt As String = ""
    Public Property DefaultCompany As String = ""
    Public Property MonitorRefreshSeconds As Integer = 30
    Public Property LastReceiveDirectory As String = ""
    Public Property DefaultSettings As New TransferSettings()
    Public Property Companies As New List(Of CompanyConfig)()
End Class

Public Class CompanyConfig
    Public Property Name As String = ""
    Public Property Machines As New List(Of MachineConfig)()
End Class

Public Class MachineConfig
    Public Property Name As String = ""
    Public Property IpMoxa As String = ""
    Public Property IpMachineWise As String = ""
    Public Property Note As String = ""
End Class

Friend Class MoxaStatusTarget
    Public Property Company As String = ""
    Public Property Machine As MachineConfig
End Class

Public Class TransferSettings
    Public Property Port As Integer = 10001
    Public Property ConnectionTimeoutSeconds As Integer = 10
    Public Property ReceiveIdleTimeoutSeconds As Integer = 15
    Public Property SendTerminator As String = "%"
    Public Property LineDelayMs As Integer = 100
    Public Property CharDelayMs As Integer = 10
    Public Property LinePaced As Boolean = True
    Public Property CharPaced As Boolean = False
    Public Property BlockPaced As Boolean = False
    Public Property BlockSizeBytes As Integer = 32
    Public Property BlockDelayMs As Integer = 100
    Public Property WaitBeforeSendSeconds As Integer = 2
    Public Property WaitAfterSendSeconds As Integer = 2
End Class