using System.Diagnostics;

namespace LmeLicenseManager;

internal sealed class MainForm : Form
{
    private readonly LicenseRepository _repository;
    private readonly TextBox _firstName = new();
    private readonly TextBox _lastName = new();
    private readonly TextBox _email = new();
    private readonly DateTimePicker _expiresAt = new();
    private readonly TextBox _notes = new();
    private readonly TextBox _licenseCode = new();
    private readonly DataGridView _grid = new();
    private readonly Label _status = new();
    private IReadOnlyList<IssuedLicense> _licenses = [];

    public MainForm(LicenseRepository repository)
    {
        _repository = repository;
        Text = "LME Pro - Gestore licenze manuali";
        MinimumSize = new Size(980, 720);
        StartPosition = FormStartPosition.CenterScreen;
        Font = new Font("Segoe UI", 9F);

        var root = new TableLayoutPanel
        {
            Dock = DockStyle.Fill,
            ColumnCount = 1,
            RowCount = 5,
            Padding = new Padding(18)
        };
        root.RowStyles.Add(new RowStyle(SizeType.AutoSize));
        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));
        Controls.Add(root);

        root.Controls.Add(BuildHeader(), 0, 0);
        root.Controls.Add(BuildIssueForm(), 0, 1);
        root.Controls.Add(BuildCodePanel(), 0, 2);
        root.Controls.Add(BuildGrid(), 0, 3);

        _status.AutoSize = true;
        _status.Padding = new Padding(0, 8, 0, 0);
        _status.ForeColor = Color.FromArgb(60, 77, 88);
        root.Controls.Add(_status, 0, 4);

        RefreshLicenses();
    }

    private Control BuildHeader()
    {
        var panel = new TableLayoutPanel { Dock = DockStyle.Top, AutoSize = true, ColumnCount = 2 };
        panel.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 100));
        panel.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));

        var text = new Label
        {
            AutoSize = true,
            Text = "Licenze manuali LME Pro\r\nEmetti codici cifrati e conserva titolari e scadenze nel registro locale.",
            Font = new Font("Segoe UI", 12F, FontStyle.Bold),
            Padding = new Padding(0, 0, 0, 14)
        };
        panel.Controls.Add(text, 0, 0);

        var commands = new FlowLayoutPanel { AutoSize = true, FlowDirection = FlowDirection.LeftToRight, Margin = new Padding(8, 0, 0, 12) };
        var openFolder = new Button { Text = "Apri archivio", AutoSize = true };
        openFolder.Click += (_, _) => Process.Start(new ProcessStartInfo("explorer.exe", _repository.StoragePath) { UseShellExecute = true });
        var exportKey = new Button { Text = "Backup chiave", AutoSize = true };
        exportKey.Click += (_, _) => ExportSigningKey();
        var importKey = new Button { Text = "Ripristina chiave", AutoSize = true };
        importKey.Click += (_, _) => ImportSigningKey();
        commands.Controls.Add(openFolder);
        commands.Controls.Add(exportKey);
        commands.Controls.Add(importKey);
        panel.Controls.Add(commands, 1, 0);
        return panel;
    }

    private Control BuildIssueForm()
    {
        var group = new GroupBox { Text = "Nuova licenza", Dock = DockStyle.Top, AutoSize = true, Padding = new Padding(12) };
        var form = new TableLayoutPanel { Dock = DockStyle.Top, AutoSize = true, ColumnCount = 4, RowCount = 3 };
        form.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 25));
        form.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 25));
        form.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 30));
        form.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 20));

        AddLabeledControl(form, "Nome", _firstName, 0, 0);
        AddLabeledControl(form, "Cognome", _lastName, 1, 0);
        AddLabeledControl(form, "Email", _email, 2, 0);
        _expiresAt.Format = DateTimePickerFormat.Custom;
        _expiresAt.CustomFormat = "dd/MM/yyyy HH:mm";
        _expiresAt.Value = DateTime.Now.AddYears(1);
        AddLabeledControl(form, "Scadenza", _expiresAt, 3, 0);

        _notes.PlaceholderText = "Riferimento fattura, cliente, note interne...";
        AddLabeledControl(form, "Note", _notes, 0, 1, 3);

        var issue = new Button
        {
            Text = "Emetti licenza",
            Dock = DockStyle.Fill,
            Height = 36,
            Margin = new Padding(6, 23, 3, 4),
            BackColor = Color.FromArgb(7, 94, 84),
            ForeColor = Color.White,
            FlatStyle = FlatStyle.Flat
        };
        issue.Click += (_, _) => IssueLicense();
        form.Controls.Add(issue, 3, 1);

        var note = new Label
        {
            AutoSize = true,
            Text = "La revoca registrata qui non disattiva un codice già consegnato e offline: la disattivazione effettiva avviene alla scadenza.",
            ForeColor = Color.FromArgb(90, 103, 111),
            Padding = new Padding(3, 8, 3, 2)
        };
        form.Controls.Add(note, 0, 2);
        form.SetColumnSpan(note, 4);
        group.Controls.Add(form);
        return group;
    }

    private Control BuildCodePanel()
    {
        var group = new GroupBox { Text = "Codice da consegnare", Dock = DockStyle.Top, Height = 122, Padding = new Padding(12) };
        var layout = new TableLayoutPanel { Dock = DockStyle.Fill, ColumnCount = 2 };
        layout.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 100));
        layout.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));

        _licenseCode.Multiline = true;
        _licenseCode.ReadOnly = true;
        _licenseCode.ScrollBars = ScrollBars.Vertical;
        _licenseCode.Dock = DockStyle.Fill;
        _licenseCode.Font = new Font("Consolas", 8.5F);
        layout.Controls.Add(_licenseCode, 0, 0);

        var copy = new Button { Text = "Copia codice", AutoSize = true, Dock = DockStyle.Top, Margin = new Padding(8, 0, 0, 0) };
        copy.Click += (_, _) => CopyCurrentCode();
        layout.Controls.Add(copy, 1, 0);
        group.Controls.Add(layout);
        return group;
    }

    private Control BuildGrid()
    {
        var panel = new TableLayoutPanel { Dock = DockStyle.Fill, ColumnCount = 1, RowCount = 2, Padding = new Padding(0, 12, 0, 0) };
        panel.RowStyles.Add(new RowStyle(SizeType.AutoSize));
        panel.RowStyles.Add(new RowStyle(SizeType.Percent, 100));

        var commands = new FlowLayoutPanel { AutoSize = true, Dock = DockStyle.Top, FlowDirection = FlowDirection.LeftToRight };
        var refresh = new Button { Text = "Aggiorna registro", AutoSize = true };
        refresh.Click += (_, _) => RefreshLicenses();
        var revoke = new Button { Text = "Segna revocata", AutoSize = true };
        revoke.Click += (_, _) => RevokeSelected();
        commands.Controls.Add(refresh);
        commands.Controls.Add(revoke);
        panel.Controls.Add(commands, 0, 0);

        _grid.Dock = DockStyle.Fill;
        _grid.ReadOnly = true;
        _grid.AllowUserToAddRows = false;
        _grid.AllowUserToDeleteRows = false;
        _grid.AutoGenerateColumns = true;
        _grid.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill;
        _grid.SelectionMode = DataGridViewSelectionMode.FullRowSelect;
        _grid.MultiSelect = false;
        _grid.SelectionChanged += (_, _) => ShowSelectedCode();
        panel.Controls.Add(_grid, 0, 1);
        return panel;
    }

    private void IssueLicense()
    {
        try
        {
            var expiry = new DateTimeOffset(_expiresAt.Value);
            var license = _repository.Issue(_firstName.Text, _lastName.Text, _email.Text, expiry, _notes.Text);
            _licenseCode.Text = license.Token;
            Clipboard.SetText(license.Token);
            _status.Text = $"Licenza {ShortId(license.LicenseId)} emessa e copiata negli appunti. Scadenza: {license.ExpiresAtUtc.ToLocalTime():dd/MM/yyyy HH:mm}.";
            RefreshLicenses(license.LicenseId);
        }
        catch (Exception error)
        {
            MessageBox.Show(this, error.GetBaseException().Message, "Licenza non emessa", MessageBoxButtons.OK, MessageBoxIcon.Warning);
        }
    }

    private void RefreshLicenses(string? selectLicenseId = null)
    {
        _licenses = _repository.GetAll();
        _grid.DataSource = _licenses.Select(item => new
        {
            Id = ShortId(item.LicenseId),
            item.Name,
            item.Email,
            Emessa = item.IssuedAtUtc.ToLocalTime().ToString("dd/MM/yyyy HH:mm"),
            Scadenza = item.ExpiresAtUtc.ToLocalTime().ToString("dd/MM/yyyy HH:mm"),
            item.Status,
            item.Notes,
            LicenseId = item.LicenseId
        }).ToList();

        if (selectLicenseId is not null)
        {
            foreach (DataGridViewRow row in _grid.Rows)
            {
                if (Equals(row.Cells["LicenseId"].Value, selectLicenseId))
                {
                    row.Selected = true;
                    _grid.CurrentCell = row.Cells[0];
                    break;
                }
            }
        }

        if (_grid.Columns.Contains("LicenseId"))
        {
            _grid.Columns["LicenseId"]!.Visible = false;
        }

        _status.Text = $"{_licenses.Count} licenze registrate. Archivio: {_repository.StoragePath}";
    }

    private void ShowSelectedCode()
    {
        var selected = GetSelectedLicense();
        if (selected is not null)
        {
            _licenseCode.Text = selected.Token;
        }
    }

    private void CopyCurrentCode()
    {
        if (!string.IsNullOrWhiteSpace(_licenseCode.Text))
        {
            Clipboard.SetText(_licenseCode.Text);
            _status.Text = "Codice licenza copiato negli appunti.";
        }
    }

    private void RevokeSelected()
    {
        var selected = GetSelectedLicense();
        if (selected is null || selected.RevokedAtUtc is not null)
        {
            return;
        }

        var answer = MessageBox.Show(
            this,
            "La revoca verrà annotata nel registro, ma un'app offline continuerà a riconoscere il codice fino alla scadenza. Continuare?",
            "Segna licenza revocata",
            MessageBoxButtons.YesNo,
            MessageBoxIcon.Warning);
        if (answer != DialogResult.Yes)
        {
            return;
        }

        _repository.MarkRevoked(selected.LicenseId);
        RefreshLicenses(selected.LicenseId);
    }

    private void ExportSigningKey()
    {
        var password = PromptPassword("Password backup", "Scegli una password di almeno 12 caratteri per cifrare la chiave.", true);
        if (password is null) return;
        using var dialog = new SaveFileDialog
        {
            Title = "Salva backup della chiave licenze",
            Filter = "Backup chiave LME (*.lmekey)|*.lmekey",
            FileName = $"LME-Pro-licenze-{DateTime.Now:yyyyMMdd}.lmekey",
            AddExtension = true
        };
        if (dialog.ShowDialog(this) != DialogResult.OK) return;
        try
        {
            _repository.ExportSigningKeyBackup(dialog.FileName, password);
            _status.Text = "Backup cifrato della chiave creato. Conserva file e password separatamente.";
        }
        catch (Exception error)
        {
            MessageBox.Show(this, error.GetBaseException().Message, "Backup non creato", MessageBoxButtons.OK, MessageBoxIcon.Warning);
        }
    }

    private void ImportSigningKey()
    {
        using var dialog = new OpenFileDialog
        {
            Title = "Apri backup della chiave licenze",
            Filter = "Backup chiave LME (*.lmekey)|*.lmekey"
        };
        if (dialog.ShowDialog(this) != DialogResult.OK) return;
        var password = PromptPassword("Password backup", "Inserisci la password usata per cifrare questa chiave.", false);
        if (password is null) return;
        var answer = MessageBox.Show(
            this,
            "La chiave di emissione corrente verrà sostituita. Importa soltanto il backup associato a questa versione dell'app.",
            "Ripristina chiave licenze",
            MessageBoxButtons.YesNo,
            MessageBoxIcon.Warning);
        if (answer != DialogResult.Yes) return;
        try
        {
            _repository.ImportSigningKeyBackup(dialog.FileName, password);
            _status.Text = "Chiave di emissione ripristinata dal backup.";
        }
        catch (Exception error)
        {
            MessageBox.Show(this, error.GetBaseException().Message, "Chiave non importata", MessageBoxButtons.OK, MessageBoxIcon.Error);
        }
    }

    private string? PromptPassword(string title, string message, bool confirm)
    {
        using var dialog = new Form
        {
            Text = title,
            Width = 470,
            Height = confirm ? 245 : 205,
            StartPosition = FormStartPosition.CenterParent,
            FormBorderStyle = FormBorderStyle.FixedDialog,
            MaximizeBox = false,
            MinimizeBox = false
        };
        var layout = new TableLayoutPanel { Dock = DockStyle.Fill, Padding = new Padding(14), RowCount = confirm ? 5 : 4, ColumnCount = 1 };
        var explanation = new Label { Text = message, AutoSize = true, MaximumSize = new Size(420, 0) };
        var password = new TextBox { UseSystemPasswordChar = true, Dock = DockStyle.Top };
        var confirmation = new TextBox { UseSystemPasswordChar = true, Dock = DockStyle.Top, Visible = confirm };
        var buttons = new FlowLayoutPanel { FlowDirection = FlowDirection.RightToLeft, Dock = DockStyle.Fill, AutoSize = true };
        var ok = new Button { Text = "OK", DialogResult = DialogResult.OK, AutoSize = true };
        var cancel = new Button { Text = "Annulla", DialogResult = DialogResult.Cancel, AutoSize = true };
        buttons.Controls.Add(ok);
        buttons.Controls.Add(cancel);
        layout.Controls.Add(explanation);
        layout.Controls.Add(new Label { Text = "Password", AutoSize = true });
        layout.Controls.Add(password);
        if (confirm)
        {
            var confirmationPanel = new TableLayoutPanel { Dock = DockStyle.Top, AutoSize = true, RowCount = 2 };
            confirmationPanel.Controls.Add(new Label { Text = "Conferma password", AutoSize = true });
            confirmationPanel.Controls.Add(confirmation);
            layout.Controls.Add(confirmationPanel);
        }
        layout.Controls.Add(buttons);
        dialog.Controls.Add(layout);
        dialog.AcceptButton = ok;
        dialog.CancelButton = cancel;
        if (dialog.ShowDialog(this) != DialogResult.OK) return null;
        if (confirm && password.Text != confirmation.Text)
        {
            MessageBox.Show(this, "Le password non coincidono.", title, MessageBoxButtons.OK, MessageBoxIcon.Warning);
            return null;
        }
        return password.Text;
    }

    private IssuedLicense? GetSelectedLicense()
    {
        if (_grid.CurrentRow?.Cells["LicenseId"].Value is not string id)
        {
            return null;
        }

        return _licenses.FirstOrDefault(item => item.LicenseId == id);
    }

    private static void AddLabeledControl(TableLayoutPanel form, string labelText, Control control, int column, int row, int columnSpan = 1)
    {
        var panel = new TableLayoutPanel { Dock = DockStyle.Fill, AutoSize = true, RowCount = 2, Margin = new Padding(3) };
        panel.RowStyles.Add(new RowStyle(SizeType.AutoSize));
        panel.RowStyles.Add(new RowStyle(SizeType.AutoSize));
        panel.Controls.Add(new Label { Text = labelText, AutoSize = true }, 0, 0);
        control.Dock = DockStyle.Top;
        control.Margin = new Padding(0, 4, 0, 0);
        panel.Controls.Add(control, 0, 1);
        form.Controls.Add(panel, column, row);
        if (columnSpan > 1)
        {
            form.SetColumnSpan(panel, columnSpan);
        }
    }

    private static string ShortId(string id) => id.Length > 8 ? id[..8].ToUpperInvariant() : id;
}