using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Linq;
using System.Windows.Forms;

namespace BoxPacker3D
{
    // Multi-box storage: each "solution" box contains its packed items
    public class BoxSolution
    {
        public Box Box;
        public List<PackedItem> PackedItems;
        public BoxSolution(Box box, List<PackedItem> packed)
        { Box = box; PackedItems = packed; }
    }

    public partial class Form1 : Form
    {

        private AppSettings _settings;
        private ItemDatabase _itemDb;

        private List<BoxSolution> _solutions = new List<BoxSolution>();
        private List<Item> _unpackedItems = new List<Item>();  // Track items that didn't fit
        private int _currentBoxIndex = 0;

        private List<ItemType> itemTypes = new List<ItemType>();
        private Viewer3D viewer;
        private GlViewer glViewer;

        private Panel panelLeft, panelRight, panelTop;
        private GroupBox grpBox, grpItems, grpResult;
        private NumericUpDown nudBoxW, nudBoxH, nudBoxD, nudBoxWallThickness;
        private NumericUpDown nudMaxW, nudMaxH, nudMaxD;
        private NumericUpDown nudWallPad, nudItemPad;
        private DataGridView dgvItems;
        private ComboBox cmbItemName;
        private NumericUpDown nudNewW, nudNewH, nudNewD, nudNewCnt;
        private Button btnAddItem, btnRemoveItem, btnPack, btnSuggest, btnClear, btnSaveTemplate, btnEditDb, btnRefreshDb;
        private Button btnExportJpg, btnExportPng, btnExportPdf;
        private Button btnPrevBox, btnNextBox;
        private Label lblEfficiency, lblPacked, lblTotal, lblBoxNav;
        private Panel panelViewer;
        private TrackBar trkRotX, trkRotY, trkZoom;
        private Label lblRotX, lblRotY, lblZoom;
        private StatusStrip statusStrip;
        private ToolStripStatusLabel statusLabel;
        private ToolStripProgressBar progressBar;

        public Form1()
        {
            // Load settings & open database BEFORE UI construction so defaults can be applied
            _settings = AppSettings.Load();
            try
            {
                _itemDb = new ItemDatabase(_settings.ResolvedDatabasePath);
            }
            catch (Exception ex)
            {
                MessageBox.Show(
                    $"Databázu kusov sa nepodarilo otvoriť:\n{_settings.ResolvedDatabasePath}\n\n{ex.Message}",
                    "Chyba databázy", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                _itemDb = null;
            }

            InitializeComponent();
            BuildUI();

            viewer = new Viewer3D(panelViewer);
            try
            {
                glViewer = new GlViewer(panelViewer);
                glViewer.ViewChanged += GlViewer_ViewChanged;
                statusLabel.Text = $"GPU renderer aktívny  |  DB: {_settings.ResolvedDatabasePath}";
            }
            catch (Exception ex)
            {
                glViewer = null;
                statusLabel.Text = $"GDI+ renderer (OpenGL nedostupný: {ex.Message})";
            }

            RefreshItemNameCombo();
        }

        private static Color C(int r, int g, int b) => Color.FromArgb(r, g, b);

        private Label MakeLabel(string text, Color? color = null)
        {
            return new Label
            {
                Text = text,
                ForeColor = color ?? C(180, 180, 200),
                AutoSize = true,
                Anchor = AnchorStyles.Left | AnchorStyles.Top,
                Margin = new Padding(3, 7, 3, 0)
            };
        }

        private NumericUpDown MakeNUD(decimal val, decimal min = 0, decimal max = 100000,
            int decimalPlaces = 0, decimal increment = 1)
        {
            return new NumericUpDown
            {
                Minimum = min, Maximum = max, Value = val,
                DecimalPlaces = decimalPlaces, Increment = increment,
                BackColor = C(45, 45, 60), ForeColor = Color.White,
                BorderStyle = BorderStyle.FixedSingle,
                Dock = DockStyle.Fill, Margin = new Padding(3)
            };
        }

        private Button MakeButton(string text, Color bg, Color fg)
        {
            var btn = new Button
            {
                Text = text, BackColor = bg, ForeColor = fg,
                FlatStyle = FlatStyle.Flat, Cursor = Cursors.Hand,
                Font = new Font("Segoe UI", 9f, FontStyle.Bold),
                Dock = DockStyle.Fill, AutoSize = false,
                Height = 32, Margin = new Padding(2)
            };
            btn.FlatAppearance.BorderColor = C(80, 80, 100);
            btn.FlatAppearance.BorderSize = 1;
            return btn;
        }

        private static GroupBox MakeGroupBox(string title)
        {
            return new GroupBox
            {
                Text = title, ForeColor = C(100, 200, 255),
                BackColor = C(35, 35, 48),
                Font = new Font("Segoe UI", 9f, FontStyle.Bold),
                Dock = DockStyle.Fill, AutoSize = true,
                AutoSizeMode = AutoSizeMode.GrowAndShrink,
                Margin = new Padding(0, 0, 0, 6),
                Padding = new Padding(6, 8, 6, 6)
            };
        }

        private static void PushRow(TableLayoutPanel tbl, Control ctrl, int row,
            SizeType st = SizeType.AutoSize, float size = 0)
        {
            tbl.RowCount = row + 1;
            tbl.RowStyles.Add(new RowStyle(st, size));
            tbl.Controls.Add(ctrl, 0, row);
        }

        private TableLayoutPanel Make3ColNudRow(
            string lbl1, NumericUpDown nud1,
            string lbl2, NumericUpDown nud2,
            string lbl3, NumericUpDown nud3)
        {
            var tbl = new TableLayoutPanel
            {
                Dock = DockStyle.Fill, AutoSize = true,
                ColumnCount = 3, RowCount = 2, Margin = new Padding(2)
            };
            tbl.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 33f));
            tbl.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 33f));
            tbl.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 34f));
            tbl.RowStyles.Add(new RowStyle(SizeType.AutoSize));
            tbl.RowStyles.Add(new RowStyle(SizeType.AutoSize));
            tbl.Controls.Add(MakeLabel(lbl1), 0, 0);
            tbl.Controls.Add(MakeLabel(lbl2), 1, 0);
            tbl.Controls.Add(MakeLabel(lbl3), 2, 0);
            tbl.Controls.Add(nud1, 0, 1);
            tbl.Controls.Add(nud2, 1, 1);
            tbl.Controls.Add(nud3, 2, 1);
            return tbl;
        }

        private void BuildUI()
        {
            this.Text = "3D Box Packer";
            this.Size = new Size(_settings.UI.WindowWidth, _settings.UI.WindowHeight);
            this.MinimumSize = new Size(1050, 720);
            this.BackColor = C(30, 30, 40);
            this.AutoScaleMode = AutoScaleMode.Dpi;
            this.AutoScaleDimensions = new SizeF(96f, 96f);

            statusStrip = new StatusStrip { BackColor = C(20, 20, 30) };
            statusLabel = new ToolStripStatusLabel("Pripravený") { ForeColor = C(100, 200, 255) };
            progressBar = new ToolStripProgressBar
            {
                Minimum = 0, Maximum = 100, Value = 0, Visible = false,
                Size = new Size(200, 16),
            };
            statusStrip.Items.Add(statusLabel);
            statusStrip.Items.Add(progressBar);
            this.Controls.Add(statusStrip);

            panelTop = new Panel { Dock = DockStyle.Top, Height = 50, BackColor = C(20, 20, 30) };
            panelTop.Controls.Add(new Label
            {
                Text = "⬛ 3D Box Packer",
                Font = new Font("Segoe UI", 16f, FontStyle.Bold),
                ForeColor = C(100, 200, 255),
                AutoSize = true, Location = new Point(15, 10)
            });
            this.Controls.Add(panelTop);

            panelLeft = new Panel
            {
                Dock = DockStyle.Left, Width = _settings.UI.LeftPanelWidth,
                BackColor = C(35, 35, 48),
                Padding = new Padding(10), AutoScroll = true
            };
            this.Controls.Add(panelLeft);

            panelRight = new Panel { Dock = DockStyle.Fill, BackColor = C(25, 25, 35) };
            this.Controls.Add(panelRight);

            BuildLeftPanel();
            BuildRightPanel();

            this.Controls.SetChildIndex(statusStrip, 0);
            this.Controls.SetChildIndex(panelRight, 1);
            this.Controls.SetChildIndex(panelLeft, 2);
            this.Controls.SetChildIndex(panelTop, 3);
        }

        private void BuildLeftPanel()
        {
            var stack = new TableLayoutPanel
            {
                Dock = DockStyle.Top, AutoSize = true,
                AutoSizeMode = AutoSizeMode.GrowAndShrink,
                ColumnCount = 1, Padding = new Padding(0), Margin = new Padding(0)
            };
            stack.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 100));
            panelLeft.Controls.Add(stack);
            int r = 0;

            // ── Min box dimensions (mm) ───────────────────────────────────────
            grpBox = MakeGroupBox("📦 Min rozmery škatule (mm)");
            nudBoxW = MakeNUD((decimal)_settings.DefaultBox.Width,  10);
            nudBoxH = MakeNUD((decimal)_settings.DefaultBox.Height, 10);
            nudBoxD = MakeNUD((decimal)_settings.DefaultBox.Depth,  10);
            nudBoxWallThickness = MakeNUD((decimal)_settings.DefaultBox.WallThickness, 0, 500, 1, 0.5m);

            // 3-column label+NUD row (wall thickness is in Izolácia group)
            var boxTbl = new TableLayoutPanel
            {
                Dock = DockStyle.Fill, AutoSize = true,
                ColumnCount = 3, RowCount = 2, Margin = new Padding(2)
            };
            boxTbl.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 33f));
            boxTbl.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 33f));
            boxTbl.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 34f));
            boxTbl.RowStyles.Add(new RowStyle(SizeType.AutoSize));
            boxTbl.RowStyles.Add(new RowStyle(SizeType.AutoSize));
            boxTbl.Controls.Add(MakeLabel("Min šírka (mm):"), 0, 0);
            boxTbl.Controls.Add(MakeLabel("Min dĺžka (mm):"), 1, 0);
            boxTbl.Controls.Add(MakeLabel("Min výška (mm):"), 2, 0);
            boxTbl.Controls.Add(nudBoxW, 0, 1);
            boxTbl.Controls.Add(nudBoxD, 1, 1);
            boxTbl.Controls.Add(nudBoxH, 2, 1);
            grpBox.Controls.Add(boxTbl);
            PushRow(stack, grpBox, r++);

            // ── Max dimensions ────────────────────────────────────────────────
            var grpMax = MakeGroupBox("📏 Max rozmery škatule (mm)");
            nudMaxW = MakeNUD((decimal)_settings.MaxBox.Width,  10);
            nudMaxH = MakeNUD((decimal)_settings.MaxBox.Height, 10);
            nudMaxD = MakeNUD((decimal)_settings.MaxBox.Depth,  10);
            
            // Validate box dimensions when max changes
            nudMaxW.ValueChanged += (s, e) => { 
                nudBoxW.Maximum = nudMaxW.Value;
                if (nudBoxW.Value > nudMaxW.Value) nudBoxW.Value = nudMaxW.Value;
            };
            nudMaxH.ValueChanged += (s, e) => { 
                nudBoxH.Maximum = nudMaxH.Value;
                if (nudBoxH.Value > nudMaxH.Value) nudBoxH.Value = nudMaxH.Value;
            };
            nudMaxD.ValueChanged += (s, e) => { 
                nudBoxD.Maximum = nudMaxD.Value;
                if (nudBoxD.Value > nudMaxD.Value) nudBoxD.Value = nudMaxD.Value;
            };
            
            grpMax.Controls.Add(Make3ColNudRow("Max šírka:", nudMaxW, "Max dĺžka:", nudMaxD, "Max výška:", nudMaxH));
            PushRow(stack, grpMax, r++);

            // ── Padding + wall thickness (mm) ────────────────────────────────
            var grpPad = MakeGroupBox("🧱 Izolácia (mm)");
            nudWallPad = MakeNUD((decimal)_settings.Padding.WallPadding, 0, 1000, 1, 5m);
            nudItemPad = MakeNUD((decimal)_settings.Padding.ItemPadding, 0, 1000, 1, 5m);
            var padTbl = new TableLayoutPanel
            {
                Dock = DockStyle.Fill, AutoSize = true,
                ColumnCount = 3, RowCount = 2, Margin = new Padding(2)
            };
            padTbl.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 34f));
            padTbl.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 33f));
            padTbl.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 33f));
            padTbl.RowStyles.Add(new RowStyle(SizeType.AutoSize));
            padTbl.RowStyles.Add(new RowStyle(SizeType.AutoSize));
            padTbl.Controls.Add(MakeLabel("Stenová izolácia:"), 0, 0);
            padTbl.Controls.Add(MakeLabel("Medikusová:"),       1, 0);
            padTbl.Controls.Add(MakeLabel("Hrúbka steny:"),     2, 0);
            padTbl.Controls.Add(nudWallPad,           0, 1);
            padTbl.Controls.Add(nudItemPad,           1, 1);
            padTbl.Controls.Add(nudBoxWallThickness,  2, 1);
            grpPad.Controls.Add(padTbl);
            PushRow(stack, grpPad, r++);

            // ── Items (mm) ────────────────────────────────────────────────────
            grpItems = MakeGroupBox("🧩 Kusy na zabalenie (mm)");
            var itemsStack = new TableLayoutPanel
            {
                Dock = DockStyle.Fill, AutoSize = true,
                ColumnCount = 1, Margin = new Padding(2)
            };
            itemsStack.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 100));

            dgvItems = new DataGridView
            {
                Dock = DockStyle.Fill, Height = 160,
                BackgroundColor = C(40, 40, 55), GridColor = C(60, 60, 80),
                BorderStyle = BorderStyle.None, RowHeadersVisible = false,
                AllowUserToAddRows = false,
                SelectionMode = DataGridViewSelectionMode.FullRowSelect,
                AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill,
                Margin = new Padding(0, 0, 0, 4)
            };
            dgvItems.DefaultCellStyle.BackColor = C(40, 40, 55);
            dgvItems.DefaultCellStyle.ForeColor = Color.White;
            dgvItems.DefaultCellStyle.SelectionBackColor = C(60, 100, 160);
            dgvItems.ColumnHeadersDefaultCellStyle.BackColor = C(30, 30, 45);
            dgvItems.ColumnHeadersDefaultCellStyle.ForeColor = C(100, 200, 255);
            dgvItems.ColumnHeadersDefaultCellStyle.Font = new Font("Segoe UI", 8.5f, FontStyle.Bold);
            dgvItems.EnableHeadersVisualStyles = false;
            dgvItems.Columns.Add("Name", "Názov");
            dgvItems.Columns.Add("W", "Š(mm)");
            dgvItems.Columns.Add("H", "V(mm)");
            dgvItems.Columns.Add("D", "D(mm)");
            dgvItems.Columns.Add("Count", "Počet");
            int ir = 0;
            PushRow(itemsStack, dgvItems, ir++, SizeType.Absolute, 165);

            // Input row 1: Názov (ComboBox s autocomplete) + Pridať + Zmazať
            var inputRow1 = new TableLayoutPanel
            {
                Dock = DockStyle.Fill, AutoSize = true, ColumnCount = 3,
                Margin = new Padding(0, 4, 0, 2)
            };
            inputRow1.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 50f));
            inputRow1.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 25f));
            inputRow1.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 25f));

            cmbItemName = new ComboBox
            {
                BackColor = C(45, 45, 60), ForeColor = Color.White,
                FlatStyle = FlatStyle.Flat,
                Dock = DockStyle.Fill, Margin = new Padding(3),
                DropDownStyle = ComboBoxStyle.DropDown,   // editable + dropdown
                AutoCompleteMode = AutoCompleteMode.SuggestAppend,
                AutoCompleteSource = AutoCompleteSource.ListItems
            };

            btnAddItem    = MakeButton("➕ Pridať",  C(40, 120, 60),  Color.White);
            btnRemoveItem = MakeButton("🗑 Zmazať", C(120, 40, 40),  Color.White);
            inputRow1.Controls.Add(cmbItemName,   0, 0);
            inputRow1.Controls.Add(btnAddItem,    1, 0);
            inputRow1.Controls.Add(btnRemoveItem, 2, 0);
            PushRow(itemsStack, inputRow1, ir++);

            // Input row 2: dimensions
            nudNewW  = MakeNUD(100, 1);
            nudNewH  = MakeNUD(100, 1);
            nudNewD  = MakeNUD(100, 1);
            nudNewCnt = MakeNUD(1, 1);
            var inputRow2 = new TableLayoutPanel
            {
                Dock = DockStyle.Fill, AutoSize = true,
                ColumnCount = 4, RowCount = 2, Margin = new Padding(0, 2, 0, 4)
            };
            inputRow2.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 25f));
            inputRow2.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 25f));
            inputRow2.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 25f));
            inputRow2.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 25f));
            inputRow2.RowStyles.Add(new RowStyle(SizeType.AutoSize));
            inputRow2.RowStyles.Add(new RowStyle(SizeType.AutoSize));
            inputRow2.Controls.Add(MakeLabel("Šírka (mm):"), 0, 0);
            inputRow2.Controls.Add(MakeLabel("Výška (mm):"), 1, 0);
            inputRow2.Controls.Add(MakeLabel("Dĺžka (mm):"), 2, 0);
            inputRow2.Controls.Add(MakeLabel("Počet ks:"),   3, 0);
            inputRow2.Controls.Add(nudNewW,   0, 1);
            inputRow2.Controls.Add(nudNewH,   1, 1);
            inputRow2.Controls.Add(nudNewD,   2, 1);
            inputRow2.Controls.Add(nudNewCnt, 3, 1);
            PushRow(itemsStack, inputRow2, ir++);

            // Input row 3: Save-to-DB + Edit-DB + Refresh-DB
            var inputRow3 = new TableLayoutPanel
            {
                Dock = DockStyle.Fill, AutoSize = true, ColumnCount = 3,
                Margin = new Padding(0, 2, 0, 2)
            };
            inputRow3.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 50f));
            inputRow3.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 25f));
            inputRow3.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 25f));
            btnSaveTemplate = MakeButton("💾 Uložiť kus do databázy", C(60, 90, 150), Color.White);
            btnEditDb       = MakeButton("📝 Spravovať DB",            C(80, 60, 120), Color.White);
            btnRefreshDb    = MakeButton("🔄 Obnoviť",                 C(50, 60, 90),  Color.White);
            inputRow3.Controls.Add(btnSaveTemplate, 0, 0);
            inputRow3.Controls.Add(btnEditDb,       1, 0);
            inputRow3.Controls.Add(btnRefreshDb,    2, 0);
            PushRow(itemsStack, inputRow3, ir++);

            // ── event handlers ────────────────────────────────────────────────

            // When user picks a name from the dropdown, auto-fill dimensions
            cmbItemName.SelectedIndexChanged += (s, e) =>
            {
                if (cmbItemName.SelectedItem is ItemTemplate t)
                {
                    nudNewW.Value = (decimal)Math.Min((double)nudNewW.Maximum, Math.Max((double)nudNewW.Minimum, t.Width));
                    nudNewH.Value = (decimal)Math.Min((double)nudNewH.Maximum, Math.Max((double)nudNewH.Minimum, t.Height));
                    nudNewD.Value = (decimal)Math.Min((double)nudNewD.Maximum, Math.Max((double)nudNewD.Minimum, t.Depth));
                    // Show clean name in the textbox (instead of the full template.ToString())
                    cmbItemName.Text = t.Name;
                    statusLabel.Text = $"Načítaný kus: {t.Name} ({t.Width}×{t.Height}×{t.Depth} mm)";
                }
            };

            // When user types a name, try to find a matching DB template (on Leave)
            cmbItemName.Leave += (s, e) =>
            {
                if (_itemDb == null) return;
                var typed = cmbItemName.Text.Trim();
                if (string.IsNullOrEmpty(typed)) return;
                var found = _itemDb.FindByName(typed);
                if (found != null)
                {
                    nudNewW.Value = (decimal)found.Width;
                    nudNewH.Value = (decimal)found.Height;
                    nudNewD.Value = (decimal)found.Depth;
                }
            };

            btnAddItem.Click += (s, e) =>
            {
                var nm = cmbItemName.Text.Trim();
                bool isCustomName = !string.IsNullOrEmpty(nm);
                if (!isCustomName) nm = $"Kus {dgvItems.Rows.Count + 1}";
                
                dgvItems.Rows.Add(nm, (int)nudNewW.Value, (int)nudNewH.Value, (int)nudNewD.Value, (int)nudNewCnt.Value);
                
                // Auto-save to DB if user provided a custom name (not auto-generated)
                if (isCustomName && _itemDb != null)
                {
                    try
                    {
                        var newTemplate = new ItemTemplate
                        {
                            Name = nm,
                            Width = (double)nudNewW.Value,
                            Height = (double)nudNewH.Value,
                            Depth = (double)nudNewD.Value
                        };
                        
                        // Check for duplicates
                        var duplicate = _itemDb.FindDuplicate(newTemplate);
                        if (duplicate != null)
                        {
                            string msg;
                            if (duplicate.Name.Equals(nm, StringComparison.OrdinalIgnoreCase))
                                msg = $"Kus s názvom \"{duplicate.Name}\" už existuje v databáze.\n\nRozmery: {duplicate.Width}×{duplicate.Height}×{duplicate.Depth} mm";
                            else
                                msg = $"Kus s rovnakými rozmermi ({duplicate.Width}×{duplicate.Height}×{duplicate.Depth} mm) už existuje v databáze pod názvom \"{duplicate.Name}\".";
                            
                            MessageBox.Show($"{msg}\n\nKus bol pridaný do zoznamu, ale neuložený do databázy.",
                                "Duplikát", MessageBoxButtons.OK, MessageBoxIcon.Information);
                            statusLabel.Text = $"Pridaný do zoznamu: {nm} (duplikát v DB)";
                        }
                        else
                        {
                            _itemDb.Upsert(newTemplate);
                            RefreshItemNameCombo();
                            statusLabel.Text = $"Pridaný do zoznamu a uložený do DB: {nm}";
                        }
                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show($"Kus pridaný do zoznamu, ale nepodarilo sa uložiť do DB:\n{ex.Message}", 
                            "Upozornenie", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                        statusLabel.Text = $"Pridaný do zoznamu: {nm} (chyba DB)";
                    }
                }
                else
                {
                    statusLabel.Text = $"Pridaný do zoznamu: {nm}";
                }
            };
            btnRemoveItem.Click += (s, e) =>
            {
                if (dgvItems.SelectedRows.Count > 0)
                    dgvItems.Rows.Remove(dgvItems.SelectedRows[0]);
            };
            btnSaveTemplate.Click += (s, e) =>
            {
                if (_itemDb == null)
                {
                    MessageBox.Show("Databáza nie je dostupná.", "Chyba");
                    return;
                }
                var nm = cmbItemName.Text.Trim();
                if (string.IsNullOrEmpty(nm))
                {
                    MessageBox.Show("Zadajte názov kusu.", "Upozornenie");
                    return;
                }
                try
                {
                    var newTemplate = new ItemTemplate
                    {
                        Name = nm,
                        Width  = (double)nudNewW.Value,
                        Height = (double)nudNewH.Value,
                        Depth  = (double)nudNewD.Value
                    };
                    
                    // Check for duplicates
                    var duplicate = _itemDb.FindDuplicate(newTemplate);
                    if (duplicate != null)
                    {
                        string msg;
                        if (duplicate.Name.Equals(nm, StringComparison.OrdinalIgnoreCase))
                            msg = $"Kus s názvom \"{duplicate.Name}\" už existuje v databáze.\n\nRozmery: {duplicate.Width}×{duplicate.Height}×{duplicate.Depth} mm";
                        else
                            msg = $"Kus s rovnakými rozmermi ({duplicate.Width}×{duplicate.Height}×{duplicate.Depth} mm) už existuje v databáze pod názvom \"{duplicate.Name}\".";
                        
                        MessageBox.Show(msg, "Duplikát", MessageBoxButtons.OK, MessageBoxIcon.Information);
                        statusLabel.Text = $"Neuložené - duplikát v DB";
                        return;
                    }
                    
                    _itemDb.Upsert(newTemplate);
                    RefreshItemNameCombo();
                    cmbItemName.Text = nm;
                    statusLabel.Text = $"Uložené do DB: {nm}";
                }
                catch (Exception ex)
                {
                    MessageBox.Show($"Chyba pri ukladaní do databázy:\n{ex.Message}", 
                        "Chyba", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    statusLabel.Text = $"Chyba pri ukladaní: {nm}";
                }
            };
            btnEditDb.Click += (s, e) =>
            {
                if (_itemDb == null)
                {
                    MessageBox.Show("Databáza nie je dostupná.", "Chyba");
                    return;
                }
                using (var editor = new ItemDatabaseEditor(_itemDb))
                {
                    editor.ShowDialog(this);
                    RefreshItemNameCombo();  // Refresh after closing editor
                    statusLabel.Text = "Editor databázy zatvorený.";
                }
            };
            btnRefreshDb.Click += (s, e) =>
            {
                RefreshItemNameCombo();
                statusLabel.Text = "Databáza obnovená.";
            };

            grpItems.Controls.Add(itemsStack);
            PushRow(stack, grpItems, r++);

            // ── Suggest box size button ───────────────────────────────────────
            btnSuggest = MakeButton("💡 Vypočítať odporúčanú veľkosť", C(25, 118, 210), Color.White);
            btnSuggest.Font = new Font("Segoe UI", 9.5f, FontStyle.Bold);
            btnSuggest.Height = 38; btnSuggest.Margin = new Padding(0, 2, 0, 2);
            btnSuggest.Click += BtnSuggest_Click;
            PushRow(stack, btnSuggest, r++);

            // ── Pack button ───────────────────────────────────────────────────
            btnPack = MakeButton("🚀 SPUSTIŤ BALENIE", C(30, 100, 200), Color.White);
            btnPack.Font = new Font("Segoe UI", 11f, FontStyle.Bold);
            btnPack.Height = 46; btnPack.Margin = new Padding(0, 4, 0, 4);
            btnPack.Click += BtnPack_Click;
            PushRow(stack, btnPack, r++);

            // ── Results ───────────────────────────────────────────────────────
            grpResult = MakeGroupBox("📊 Výsledky");
            var resTbl = new TableLayoutPanel
            {
                Dock = DockStyle.Fill, AutoSize = true,
                ColumnCount = 1, Margin = new Padding(2)
            };
            resTbl.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 100));
            lblPacked    = MakeLabel("Zabalené: -",     C(120, 220, 120));
            lblTotal     = MakeLabel("Celkom kusov: -", C(220, 180, 80));
            lblEfficiency= MakeLabel("Využitie: -",     C(100, 200, 255));
            lblPacked.Font = lblTotal.Font = lblEfficiency.Font = new Font("Segoe UI", 9f, FontStyle.Bold);
            resTbl.Controls.Add(lblPacked,     0, 0); resTbl.RowStyles.Add(new RowStyle(SizeType.AutoSize));
            resTbl.Controls.Add(lblTotal,      0, 1); resTbl.RowStyles.Add(new RowStyle(SizeType.AutoSize));
            resTbl.Controls.Add(lblEfficiency, 0, 2); resTbl.RowStyles.Add(new RowStyle(SizeType.AutoSize));
            grpResult.Controls.Add(resTbl);
            PushRow(stack, grpResult, r++);

            // ── Box navigation ────────────────────────────────────────────────
            var grpNav = MakeGroupBox("📦 Navigácia škatúľ");
            var navTbl = new TableLayoutPanel
            {
                Dock = DockStyle.Fill, AutoSize = true,
                ColumnCount = 3, Margin = new Padding(2)
            };
            navTbl.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 33f));
            navTbl.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 34f));
            navTbl.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 33f));

            btnPrevBox = MakeButton("◀ Predošlá", C(60, 80, 120), Color.White);
            btnPrevBox.Click += (s, e) => { if (_currentBoxIndex > 0) { _currentBoxIndex--; ShowCurrentBox(); } };

            lblBoxNav = MakeLabel("Škatuľa: -", C(220, 220, 240));
            lblBoxNav.Font = new Font("Segoe UI", 9.5f, FontStyle.Bold);
            lblBoxNav.TextAlign = ContentAlignment.MiddleCenter;
            lblBoxNav.Dock = DockStyle.Fill;
            lblBoxNav.Margin = new Padding(0);

            btnNextBox = MakeButton("Ďalšia ▶", C(60, 80, 120), Color.White);
            btnNextBox.Click += (s, e) => { if (_currentBoxIndex < _solutions.Count - 1) { _currentBoxIndex++; ShowCurrentBox(); } };

            navTbl.Controls.Add(btnPrevBox, 0, 0);
            navTbl.Controls.Add(lblBoxNav,  1, 0);
            navTbl.Controls.Add(btnNextBox, 2, 0);
            grpNav.Controls.Add(navTbl);
            PushRow(stack, grpNav, r++);

            // ── Export ────────────────────────────────────────────────────────
            var grpExport = MakeGroupBox("💾 Export");
            var expTbl = new TableLayoutPanel
            {
                Dock = DockStyle.Fill, AutoSize = true,
                ColumnCount = 3, Margin = new Padding(2)
            };
            expTbl.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 33));
            expTbl.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 33));
            expTbl.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 34));
            btnExportPng = MakeButton("PNG", C(40, 80, 140), Color.White);
            btnExportJpg = MakeButton("JPG", C(40, 100, 80), Color.White);
            btnExportPdf = MakeButton("PDF (vrstvy)", C(140, 50, 30), Color.White);
            btnExportPng.Click += (s, e) => ExportImage(ImageFormat.Png, "png");
            btnExportJpg.Click += (s, e) => ExportImage(ImageFormat.Jpeg, "jpg");
            btnExportPdf.Click += (s, e) => ExportPdf();
            expTbl.Controls.Add(btnExportPng, 0, 0);
            expTbl.Controls.Add(btnExportJpg, 1, 0);
            expTbl.Controls.Add(btnExportPdf, 2, 0);
            grpExport.Controls.Add(expTbl);
            PushRow(stack, grpExport, r++);

            // ── Clear ─────────────────────────────────────────────────────────
            btnClear = MakeButton("🔄 Vymazať všetko", C(60, 40, 80), C(200, 180, 220));
            btnClear.Margin = new Padding(0, 4, 0, 4);
            btnClear.Click += (s, e) =>
            {
                dgvItems.Rows.Clear();
                _solutions.Clear();
                _currentBoxIndex = 0;
                viewer.Clear();
                glViewer?.Clear();
                lblPacked.Text = "Zabalené: -";
                lblTotal.Text  = "Celkom kusov: -";
                lblEfficiency.Text = "Využitie: -";
                lblBoxNav.Text = "Škatuľa: -";
                statusLabel.Text = "Vymazané";
            };
            PushRow(stack, btnClear, r++);
        }

        private void BuildRightPanel()
        {
            var pnlControls = new TableLayoutPanel
            {
                Dock = DockStyle.Bottom,
                Height = 70,  // increased from 58 to make room for labels below sliders
                BackColor = C(20, 20, 30),
                ColumnCount = 7,
                Padding = new Padding(6, 8, 6, 8)  // more vertical padding
            };
            pnlControls.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));
            pnlControls.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 28));
            pnlControls.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));
            pnlControls.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 28));
            pnlControls.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));
            pnlControls.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 24));
            pnlControls.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 16));
            panelRight.Controls.Add(pnlControls);

            TrackBar MakeTrk(int min, int max, int val, int tick)
                => new TrackBar
                {
                    Minimum = min, Maximum = max, Value = val,
                    BackColor = C(20, 20, 30),
                    Dock = DockStyle.Fill,
                    TickFrequency = tick
                };

            int initRotX = Math.Clamp(_settings.View.InitialRotationX, -90, 90);
            int initRotY = Math.Clamp(_settings.View.InitialRotationY, -90, 90);
            int initZoom = Math.Clamp(_settings.View.InitialZoomPercent, 10, 300);

            lblRotX = new Label
            {
                Text = $"Rot X: {initRotX}°",
                ForeColor = C(100, 200, 255),
                AutoSize = true,
                Anchor = AnchorStyles.Left | AnchorStyles.Top,
                TextAlign = ContentAlignment.TopLeft,
                Margin = new Padding(0, 0, 4, 0)
            };
            trkRotX = MakeTrk(-90, 90, initRotX, 15);
            trkRotX.Scroll += (s, e) => { lblRotX.Text = $"Rot X: {trkRotX.Value}°"; Rerender(); };

            lblRotY = new Label
            {
                Text = $"Rot Y: {initRotY}°",
                ForeColor = C(100, 200, 255),
                AutoSize = true,
                Anchor = AnchorStyles.Left | AnchorStyles.Top,
                TextAlign = ContentAlignment.TopLeft,
                Margin = new Padding(4, 0, 4, 0)
            };
            trkRotY = MakeTrk(-90, 90, initRotY, 15);
            trkRotY.Scroll += (s, e) => { lblRotY.Text = $"Rot Y: {trkRotY.Value}°"; Rerender(); };

            lblZoom = new Label
            {
                Text = $"Zoom: {initZoom}%",
                ForeColor = C(100, 255, 180),
                AutoSize = true,
                Anchor = AnchorStyles.Left | AnchorStyles.Top,
                TextAlign = ContentAlignment.TopLeft,
                Margin = new Padding(4, 0, 4, 0)
            };
            trkZoom = MakeTrk(10, 300, initZoom, 10);
            trkZoom.Scroll += (s, e) => { lblZoom.Text = $"Zoom: {trkZoom.Value}%"; Rerender(); };

            var lblHint = new Label
            {
                Text = "💡 Ťahaj myšou / koliesko zoom",
                ForeColor = C(80, 80, 100),
                AutoSize = false,
                Dock = DockStyle.Fill,
                TextAlign = ContentAlignment.MiddleLeft,
                Margin = new Padding(6, 0, 0, 0)
            };

            pnlControls.Controls.Add(lblRotX, 0, 0);
            pnlControls.Controls.Add(trkRotX, 1, 0);
            pnlControls.Controls.Add(lblRotY, 2, 0);
            pnlControls.Controls.Add(trkRotY, 3, 0);
            pnlControls.Controls.Add(lblZoom, 4, 0);
            pnlControls.Controls.Add(trkZoom, 5, 0);
            pnlControls.Controls.Add(lblHint,  6, 0);

            panelViewer = new Panel { Dock = DockStyle.Fill, BackColor = C(18, 18, 28) };
            panelRight.Controls.Add(panelViewer);
        }

        private void GlViewer_ViewChanged(object sender, GlViewer.ViewArgs e)
        {
            int rx = Math.Clamp((int)e.RotX, trkRotX.Minimum, trkRotX.Maximum);
            int ry = Math.Clamp((int)e.RotY, trkRotY.Minimum, trkRotY.Maximum);
            int zm = Math.Clamp((int)(e.Zoom * 100), trkZoom.Minimum, trkZoom.Maximum);
            trkRotX.Value = rx; lblRotX.Text = $"Rot X: {rx}°";
            trkRotY.Value = ry; lblRotY.Text = $"Rot Y: {ry}°";
            trkZoom.Value = zm; lblZoom.Text = $"Zoom: {zm}%";
        }

        private void Rerender()
        {
            if (_solutions.Count == 0) return;
            var sol = _solutions[_currentBoxIndex];
            double wallPad = (double)nudWallPad.Value;
            double itemPad = (double)nudItemPad.Value;
            double rotX = trkRotX.Value, rotY = trkRotY.Value, zoom = trkZoom.Value / 100.0;

            if (glViewer != null)
                glViewer.Render(sol.PackedItems, sol.Box, rotX, rotY, zoom, wallPad, itemPad);
            else
                viewer?.Render(sol.PackedItems, sol.Box, rotX, rotY, zoom, wallPad, itemPad);
        }

        private void ShowCurrentBox()
        {
            if (_solutions.Count == 0) return;
            lblBoxNav.Text = $"Škatuľa {_currentBoxIndex + 1} / {_solutions.Count}";
            var sol = _solutions[_currentBoxIndex];
            double outerVol = sol.Box.W * sol.Box.H * sol.Box.D;
            double wt = sol.Box.WallThickness;
            double innerVol = Math.Max(0, sol.Box.W - 2 * wt)
                            * Math.Max(0, sol.Box.H - 2 * wt)
                            * Math.Max(0, sol.Box.D - 2 * wt);
            double usedVol  = sol.PackedItems.Sum(p => p.RW * p.RH * p.RD);
            double effOuter = outerVol > 0 ? usedVol / outerVol * 100.0 : 0;
            double effInner = innerVol > 0 ? usedVol / innerVol * 100.0 : 0;
            lblEfficiency.Text = $"Využitie: {effOuter:F1}% (celok) | {effInner:F1}% (bez stien)  " +
                                 $"({sol.Box.W:F0}×{sol.Box.D:F0}×{sol.Box.H:F0} mm)";
            Rerender();
        }

        // ── packing logic ─────────────────────────────────────────────────────

        private void BtnPack_Click(object sender, EventArgs e)
        {
            if (dgvItems.Rows.Count == 0)
            {
                MessageBox.Show("Pridajte aspoň jeden kus!", "Upozornenie",
                    MessageBoxButtons.OK, MessageBoxIcon.Warning);
                return;
            }

            double wallPad       = (double)nudWallPad.Value;
            double itemPad       = (double)nudItemPad.Value;
            double wallThickness = (double)nudBoxWallThickness.Value;
            double maxW          = (double)nudMaxW.Value;
            double maxH          = (double)nudMaxH.Value;
            double maxD          = (double)nudMaxD.Value;

            var colors      = GenerateColors(dgvItems.Rows.Count);
            double edge     = wallPad + wallThickness;
            double maxUsableW = maxW - 2 * edge;
            double maxUsableH = maxH - 2 * edge;
            double maxUsableD = maxD - 2 * edge;

            if (maxUsableW <= 0 || maxUsableH <= 0 || maxUsableD <= 0)
            {
                MessageBox.Show(
                    $"Kombinácia izolácie ({wallPad} mm) a hrúbky steny ({wallThickness} mm) je príliš veľká.\n" +
                    $"Použiteľný priestor v maximálnej škatuli je záporný!\n\n" +
                    $"Použiteľný priestor: {maxUsableW:F0}×{maxUsableH:F0}×{maxUsableD:F0} mm\n" +
                    $"Znížte izoláciu alebo hrúbku steny.",
                    "Chyba konfigurácie", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }

            // ── Parse and validate items ──────────────────────────────────────
            var allItems = new List<Item>();
            for (int i = 0; i < dgvItems.Rows.Count; i++)
            {
                var row  = dgvItems.Rows[i];
                string name = row.Cells["Name"].Value?.ToString() ?? $"Kus {i + 1}";
                double w = Convert.ToDouble(row.Cells["W"].Value);
                double h = Convert.ToDouble(row.Cells["H"].Value);
                double d = Convert.ToDouble(row.Cells["D"].Value);
                int    cnt = Convert.ToInt32(row.Cells["Count"].Value);

                if (w <= 0 || h <= 0 || d <= 0)
                {
                    MessageBox.Show($"Kus '{name}' má neplatné rozmery ({w}×{h}×{d} mm).\nVšetky rozmery musia byť väčšie ako 0.",
                        "Chyba", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    return;
                }

                bool fitsNormal  = (w <= maxUsableW && h <= maxUsableH && d <= maxUsableD);
                bool fitsRotated = (d <= maxUsableW && h <= maxUsableH && w <= maxUsableD);
                if (!fitsNormal && !fitsRotated)
                {
                    MessageBox.Show(
                        $"Kus '{name}' ({w}×{h}×{d} mm) sa nezmestí do maximálnej škatule.\n\n" +
                        $"Max použiteľný priestor: {maxUsableW:F0}×{maxUsableH:F0}×{maxUsableD:F0} mm\n" +
                        $"(po odpočítaní izolácie {wallPad} mm a steny {wallThickness} mm)\n\n" +
                        $"Zväčšite maximálne rozmery alebo zmenšite kus.",
                        "Kus sa nezmestí", MessageBoxButtons.OK, MessageBoxIcon.Error);
                    return;
                }

                for (int j = 0; j < cnt; j++) allItems.Add(new Item(name, w, h, d, colors[i]));
            }

            // ── Calculate number of boxes ─────────────────────────────────────
            double totalItemVol = allItems.Sum(i => i.Volume);
            double maxInnerVol  = maxUsableW * maxUsableH * maxUsableD;
            int    boxCount     = Math.Max(1, (int)Math.Ceiling(totalItemVol / maxInnerVol));

            string confirmMsg =
                $"Celkový objem kusov:          {totalItemVol / 1000.0:F0} cm³\n" +
                $"Max. objem škatule (bez iz.): {maxInnerVol / 1000.0:F0} cm³\n\n" +
                $"Odhadovaný počet škatúľ: {boxCount}\n" +
                $"(každý typ kusu zostane celý v jednej škatuli)\n\n" +
                $"Pokračovať s balením do {boxCount} škatúľ?";

            if (MessageBox.Show(confirmMsg, "Potvrdenie balenia",
                    MessageBoxButtons.YesNo, MessageBoxIcon.Question) != DialogResult.Yes)
                return;

            // ── Partition types into bins (LPT) ───────────────────────────────
            var bins = PartitionTypesToBins(allItems, boxCount)
                           .Where(b => b.Count > 0).ToList();

            _solutions.Clear();
            _unpackedItems.Clear();
            _currentBoxIndex = 0;
            progressBar.Visible = true;
            progressBar.Value   = 0;

            for (int binIdx = 0; binIdx < bins.Count; binIdx++)
            {
                var binItems = bins[binIdx];
                int boxNum   = binIdx + 1;

                statusLabel.Text = $"Hľadám optimálnu škatuľu {boxNum}/{bins.Count}...";
                Application.DoEvents();

                double minW = (double)nudBoxW.Value;
                double minH = (double)nudBoxH.Value;
                double minD = (double)nudBoxD.Value;

                statusLabel.Text = $"Balím škatuľu {boxNum}/{bins.Count}...";
                Application.DoEvents();

                var minBox = new Box(minW, minH, minD, wallThickness);
                var maxBox2 = new Box(maxW, maxH, maxD, wallThickness);
                var (packed, packBox, binUnpacked) = new LayerPacker().Pack(
                    binItems, minBox, maxBox2, wallPad, itemPad, wallThickness);

                _solutions.Add(new BoxSolution(packBox, packed));
                _unpackedItems.AddRange(binUnpacked);
            }

            // ── Update result labels ──────────────────────────────────────────
            int totalPacked = _solutions.Sum(s => s.PackedItems.Count);
            lblPacked.Text  = $"Zabalené: {totalPacked} / {allItems.Count} kusov";
            lblTotal.Text   = $"Počet škatúľ: {_solutions.Count}";

            if (_unpackedItems.Count > 0)
            {
                lblPacked.Text += $" | Nezabalené: {_unpackedItems.Count}";
                lblPacked.ForeColor = Color.FromArgb(211, 47, 47);
                MessageBox.Show(
                    $"{_unpackedItems.Count} kusov sa nepodarilo zabaliť.\n" +
                    $"Skúste zväčšiť maximálne rozmery škatule alebo znížiť izoláciu.",
                    "Nezabalené kusy", MessageBoxButtons.OK, MessageBoxIcon.Warning);
            }
            else
            {
                lblPacked.ForeColor = Color.FromArgb(56, 142, 60);
            }

            if (_solutions.Count > 0) ShowCurrentBox();
            else lblEfficiency.Text = "Využitie: -";

            progressBar.Visible = false;
            statusLabel.Text = $"Hotovo! {_solutions.Count} škatúľ, {totalPacked}/{allItems.Count} kusov";
        }

        /// <summary>
        /// LPT (Longest Processing Time First) partitioning — assigns item types to N bins
        /// so that bin volumes are as equal as possible. A type is never split across bins.
        /// </summary>
        private List<List<Item>> PartitionTypesToBins(List<Item> allItems, int N)
        {
            var typeGroups = allItems
                .GroupBy(i => i.Name)
                .Select(g => new { Items = g.ToList(), TotalVolume = g.Sum(i => i.Volume), MaxHeight = g.Max(i => i.H) })
                .OrderByDescending(g => g.MaxHeight)
                .ToList();

            var bins  = Enumerable.Range(0, N).Select(_ => new List<Item>()).ToList();
            var loads = new double[N];

            foreach (var tg in typeGroups)
            {
                int minBin = 0;
                for (int i = 1; i < N; i++)
                    if (loads[i] < loads[minBin]) minBin = i;
                bins[minBin].AddRange(tg.Items);
                loads[minBin] += tg.TotalVolume;
            }

            return bins;
        }

        private (Box? box, List<PackedItem> packed, int totalCount) SuggestBoxSize(
            List<Item> items, double maxW, double maxH, double maxD,
            double wallPad, double itemPad, double wallThickness)
        {
            int totalCount = items.Count;
            double minW = (double)nudBoxW.Value;
            double minH = (double)nudBoxH.Value;
            double minD = (double)nudBoxD.Value;

            progressBar.Visible = true;
            progressBar.Value   = 0;
            statusLabel.Text    = "Hľadám optimálnu škatuľu...";
            Application.DoEvents();

            var minBox = new Box(minW, minH, minD, wallThickness);
            var maxBox = new Box(maxW, maxH, maxD, wallThickness);
            var (packed, box, unpacked) = new LayerPacker().Pack(
                items, minBox, maxBox, wallPad, itemPad, wallThickness);

            progressBar.Visible = false;

            if (packed.Count == 0)
                return (null, new List<PackedItem>(), totalCount);

            return (box, packed, totalCount);
        }

        private void BtnSuggest_Click(object? sender, EventArgs e)
        {
            if (dgvItems.Rows.Count == 0)
            {
                MessageBox.Show("Pridajte najprv kusy do zoznamu!", "Upozornenie", 
                    MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }

            var allItems = new List<Item>();
            var colors = GenerateColors(dgvItems.Rows.Count);

            for (int i = 0; i < dgvItems.Rows.Count; i++)
            {
                var row = dgvItems.Rows[i];
                if (row.IsNewRow) continue;
                var name = row.Cells[0].Value?.ToString() ?? "";
                var w = Convert.ToDouble(row.Cells[1].Value ?? 0.0);
                var h = Convert.ToDouble(row.Cells[2].Value ?? 0.0);
                var d = Convert.ToDouble(row.Cells[3].Value ?? 0.0);
                var count = Convert.ToInt32(row.Cells[4].Value ?? 1);
                for (int j = 0; j < count; j++)
                    allItems.Add(new Item(name, w, h, d, colors[i]));
            }

            if (allItems.Count == 0)
            {
                MessageBox.Show("Pridajte najprv kusy do zoznamu!", "Upozornenie", 
                    MessageBoxButtons.OK, MessageBoxIcon.Information);
                return;
            }

            var maxW = (double)nudMaxW.Value;
            var maxH = (double)nudMaxH.Value;
            var maxD = (double)nudMaxD.Value;
            var wallPad = (double)nudWallPad.Value;
            var itemPad = (double)nudItemPad.Value;
            var wallThickness = (double)nudBoxWallThickness.Value;

            statusLabel.Text = "Počítam optimálnu veľkosť škatule...";
            Application.DoEvents();

            var (suggestedBox, sugPacked, sugTotalCount) = SuggestBoxSize(allItems, maxW, maxH, maxD, wallPad, itemPad, wallThickness);

            if (suggestedBox == null)
            {
                MessageBox.Show(
                    $"Kusy sa nezmestia do maximálnej škatule ({maxW:F0}×{maxD:F0}×{maxH:F0} mm).\n\n" +
                    $"Skúste:\n" +
                    $"• Zväčšiť maximálne rozmery (📏 Max rozmery škatule)\n" +
                    $"• Zmenšiť hrúbku steny alebo stenovú/medzi-kusovú izoláciu\n" +
                    $"• Použiť viacero škatúľ (multi-box balenie)\n" +
                    $"• Odstrániť niektoré kusy",
                    "Nezmestí sa do maximálnej škatule", MessageBoxButtons.OK, MessageBoxIcon.Warning);
                statusLabel.Text = "Nezmestí sa do maximálnej škatule";
                return;
            }

            int sugPackedCount = sugPacked.Count;
            string fitInfo = sugPackedCount >= sugTotalCount
                ? $"📦 {suggestedBox.W:F0} × {suggestedBox.D:F0} × {suggestedBox.H:F0} mm\n" +
                  $"(zmestí všetkých {sugTotalCount} kusov, minimálna veľkosť)"
                : $"📦 {suggestedBox.W:F0} × {suggestedBox.D:F0} × {suggestedBox.H:F0} mm\n" +
                  $"(zmestí {sugPackedCount} z {sugTotalCount} kusov — maximum v daných rozmeroch)\n" +
                  $"Zvyšných {sugTotalCount - sugPackedCount} kusov bude potrebovať ďalšiu škatuľu.";

            var dr = MessageBox.Show(
                $"Pre {allItems.Count} kusov odporúčam škatuľu:\n\n" +
                fitInfo + "\n\n" +
                $"Min škatuľa: {nudBoxW.Value} × {nudBoxD.Value} × {nudBoxH.Value} mm\n" +
                $"Maximum: {maxW:F0} × {maxD:F0} × {maxH:F0} mm\n\n" +
                $"Chcete použiť odporúčanú veľkosť?",
                "Odporúčaná veľkosť škatule", 
                MessageBoxButtons.YesNo, 
                MessageBoxIcon.Question);

            if (dr == DialogResult.Yes)
            {
                _solutions.Clear();
                _unpackedItems.Clear();
                _currentBoxIndex = 0;
                _solutions.Add(new BoxSolution(suggestedBox, sugPacked));
                var packedSet = new HashSet<Item>(sugPacked.Select(p => p.Item));
                foreach (var item in allItems)
                    if (!packedSet.Contains(item)) _unpackedItems.Add(item);

                int totalPacked = sugPacked.Count;
                lblPacked.Text = $"Zabalené: {totalPacked} / {allItems.Count} kusov";
                lblTotal.Text  = $"Počet škatúľ: 1";
                lblPacked.ForeColor = _unpackedItems.Count > 0
                    ? Color.FromArgb(211, 47, 47)
                    : Color.FromArgb(56, 142, 60);
                if (_unpackedItems.Count > 0)
                    lblPacked.Text += $" | Nezabalené: {_unpackedItems.Count}";
                ShowCurrentBox();
                statusLabel.Text = $"Hotovo! {totalPacked}/{allItems.Count} kusov v škatuli {suggestedBox.W:F0}×{suggestedBox.D:F0}×{suggestedBox.H:F0} mm";
            }
            else
            {
                statusLabel.Text = "Odporúčaná veľkosť nezmenená";
            }
        }

        /// <summary>
        /// Reloads the item name dropdown from the database and configures autocomplete.
        /// </summary>
        private void RefreshItemNameCombo()
        {
            if (cmbItemName == null) return;
            string current = cmbItemName.Text;
            cmbItemName.Items.Clear();
            if (_itemDb == null) return;

            try
            {
                var templates = _itemDb.GetAll();
                foreach (var t in templates) cmbItemName.Items.Add(t);

                // Populate auto-complete source with bare names
                var src = new AutoCompleteStringCollection();
                foreach (var t in templates) src.Add(t.Name);
                cmbItemName.AutoCompleteCustomSource = src;
                cmbItemName.AutoCompleteSource = AutoCompleteSource.CustomSource;

                cmbItemName.Text = current; // preserve user input
            }
            catch (Exception ex)
            {
                MessageBox.Show($"Chyba pri čítaní z databázy:\n{ex.Message}", 
                    "Chyba", MessageBoxButtons.OK, MessageBoxIcon.Error);
                statusLabel.Text = $"Chyba čítania DB: {ex.Message}";
            }
        }

        private Color[] GenerateColors(int count)
        {
            var palette = new[] {
                C(200,80,80), C(80,180,80), C(80,120,220), C(220,180,50), C(180,80,180),
                C(80,200,200), C(230,130,50), C(100,200,150), C(200,100,150), C(150,150,220)
            };
            var r = new Color[count];
            for (int i = 0; i < count; i++) r[i] = palette[i % palette.Length];
            return r;
        }

        // ── export ────────────────────────────────────────────────────────────

        private void ExportImage(ImageFormat fmt, string ext)
        {
            if (_solutions.Count == 0)
            { MessageBox.Show("Najprv spustite balenie!"); return; }
            var sol = _solutions[_currentBoxIndex];
            var dlg = new SaveFileDialog { Filter = $"{ext.ToUpper()}|*.{ext}", FileName = $"box{_currentBoxIndex + 1}.{ext}" };
            if (dlg.ShowDialog() == DialogResult.OK)
            {
                viewer.RenderToBitmap(sol.PackedItems, sol.Box,
                    trkRotX.Value, trkRotY.Value, trkZoom.Value / 100.0, 1200, 800,
                    (double)nudWallPad.Value, (double)nudItemPad.Value).Save(dlg.FileName, fmt);
                statusLabel.Text = $"Exportované: {dlg.FileName}";
                MessageBox.Show($"Uložené:\n{dlg.FileName}", "Export úspešný");
            }
        }

        private void ExportPdf()
        {
            if (_solutions.Count == 0)
            { MessageBox.Show("Najprv spustite balenie!"); return; }

            var dlg = new SaveFileDialog { Filter = "PDF|*.pdf", FileName = "balenie_3d.pdf" };
            if (dlg.ShowDialog() != DialogResult.OK) return;

            statusLabel.Text = "Generujem PDF...";
            Application.DoEvents();

            double rotX = trkRotX.Value, rotY = trkRotY.Value, zoom = trkZoom.Value / 100.0;
            double wallPad = (double)nudWallPad.Value, itemPad = (double)nudItemPad.Value;

            var allLayerBitmaps = new List<Bitmap>();
            var allLayers = new List<(double, double)>();
            var allOverviews = new List<Bitmap>();

            // For each box, generate layer + overview
            foreach (var sol in _solutions)
            {
                var layers = Viewer3D.GetLayers(sol.PackedItems);
                for (int layerIdx = 0; layerIdx < layers.Count; layerIdx++)
                {
                    var layer = layers[layerIdx];
                    var bmp = viewer.RenderLayerToBitmap(
                        sol.PackedItems, sol.Box, rotX, rotY, zoom,
                        layer.YMin, layer.YMax,
                        layerIdx, layers.Count, 1000, 700, wallPad, itemPad, whiteBg: true);
                    allLayerBitmaps.Add(bmp);
                    allLayers.Add(layer);
                }

                var overview = viewer.RenderToBitmap(
                    sol.PackedItems, sol.Box, rotX, rotY, zoom, 1000, 700, wallPad, itemPad, whiteBg: true);
                allOverviews.Add(overview);
            }

            PdfExporter.Export(dlg.FileName, _solutions, allOverviews, allLayerBitmaps, allLayers, wallPad, itemPad, _unpackedItems);

            foreach (var b in allLayerBitmaps) b.Dispose();
            foreach (var b in allOverviews) b.Dispose();

            statusLabel.Text = $"PDF ({allLayerBitmaps.Count} vrstiev + {_solutions.Count} škatúľ)";
            MessageBox.Show($"PDF uložené:\n{dlg.FileName}", "Export úspešný");
        }

        private void InitializeComponent()
        {
            this.SuspendLayout();
            this.AutoScaleDimensions = new SizeF(96F, 96F);
            this.AutoScaleMode = AutoScaleMode.Dpi;
            this.ResumeLayout(false);
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing) glViewer?.Dispose();
            base.Dispose(disposing);
        }
    }
}