using System;
using System.IO;
using System.Windows.Controls;
using System.Windows;
using System.Collections.Generic;
using System.Linq;

namespace TapeCatalog.Methods
{
    // Reusable helper methods for copy-related UI functionality
    public static class Copy
    {
        // guard to prevent recursive Checked/Unchecked handling while we programmatically change states
        private static bool _suppressCheckEvents = false;
        public static void PopulateTree(TreeView tree, string path)
        {
            if (tree == null) return;
            tree.Items.Clear();
            if (string.IsNullOrWhiteSpace(path) || !Directory.Exists(path)) return;

            var rootDir = new DirectoryInfo(path);
            var rootItem = CreateDirectoryNode(rootDir);
            rootItem.IsExpanded = true;
            tree.Items.Add(rootItem);
        }

        public static TreeViewItem CreateDirectoryNode(DirectoryInfo dir)
        {
            var item = new TreeViewItem { Tag = dir.FullName };

            // Create header with a checkbox for the directory as well
            var headerPanel = new StackPanel { Orientation = Orientation.Horizontal };
            var dirCb = new CheckBox { VerticalAlignment = VerticalAlignment.Center, Margin = new Thickness(0, 0, 4, 0) };
            var dirTb = new TextBlock { Text = dir.Name, VerticalAlignment = VerticalAlignment.Center };
            headerPanel.Children.Add(dirCb);
            headerPanel.Children.Add(dirTb);
            item.Header = headerPanel;

            try
            {
                // add subdirectories
                foreach (var sub in dir.GetDirectories())
                {
                    item.Items.Add(CreateDirectoryNode(sub));
                }

                // add files
                foreach (var f in dir.GetFiles())
                {
                    var fileItem = new TreeViewItem { Tag = f.FullName };
                    var sp = new StackPanel { Orientation = Orientation.Horizontal };
                    var cb = new CheckBox { VerticalAlignment = VerticalAlignment.Center, Margin = new Thickness(0, 0, 4, 0) };
                    var tb = new TextBlock { Text = f.Name, VerticalAlignment = VerticalAlignment.Center };
                    sp.Children.Add(cb);
                    sp.Children.Add(tb);
                    fileItem.Header = sp;
                    item.Items.Add(fileItem);
                }
            }
            catch
            {
                // ignore access exceptions
            }

            // Wire events to propagate state to children when directory checkbox is toggled
            dirCb.Checked += (s, e) =>
            {
                if (_suppressCheckEvents) return;
                try { _suppressCheckEvents = true; SetCheckedState(item, true); }
                finally { _suppressCheckEvents = false; }
            };
            dirCb.Unchecked += (s, e) =>
            {
                if (_suppressCheckEvents) return;
                try { _suppressCheckEvents = true; SetCheckedState(item, false); }
                finally { _suppressCheckEvents = false; }
            };

            return item;
        }

        private static void SetCheckedState(TreeViewItem node, bool isChecked)
        {
            foreach (var it in node.Items)
            {
                if (it is TreeViewItem child)
                {
                    // child header expected to be a StackPanel with a CheckBox as first child
                    if (child.Header is StackPanel sp && sp.Children.Count > 0)
                    {
                        foreach (var ch in sp.Children)
                        {
                            if (ch is CheckBox childCb)
                            {
                                childCb.IsChecked = isChecked;
                                break;
                            }
                        }
                    }

                    // recurse into grandchildren
                    if (child.Items != null && child.Items.Count > 0)
                    {
                        SetCheckedState(child, isChecked);
                    }
                }
            }
        }

        // Collect checked files and copy them to archive preserving relative folders
        public static Tuple<int,int> CopySelectedToArchive(TreeView tree, string sourceRoot, string archivePath)
        {
            if (tree == null) return Tuple.Create(0, 0);
            var files = new List<string>();
            foreach (var it in tree.Items)
            {
                if (it is TreeViewItem tvi)
                    CollectCheckedFiles(tvi, files);
            }

            int copied = 0, failed = 0;
            foreach (var src in files)
            {
                try
                {
                    var fileDir = System.IO.Path.GetDirectoryName(src) ?? string.Empty;
                    string relative;
                    if (!string.IsNullOrWhiteSpace(sourceRoot) && fileDir.StartsWith(sourceRoot, StringComparison.OrdinalIgnoreCase))
                        relative = fileDir.Substring(sourceRoot.Length).TrimStart(System.IO.Path.DirectorySeparatorChar, System.IO.Path.AltDirectorySeparatorChar);
                    else
                        relative = System.IO.Path.GetFileName(fileDir);

                    var destDir = System.IO.Path.Combine(archivePath, relative);
                    Directory.CreateDirectory(destDir);
                    var destFile = System.IO.Path.Combine(destDir, System.IO.Path.GetFileName(src));
                    File.Copy(src, destFile, true);
                    copied++;
                }
                catch
                {
                    failed++;
                }
            }

            return Tuple.Create(copied, failed);
        }

        // Return a list of all checked file paths in the tree
        public static List<string> GetCheckedFiles(TreeView tree)
        {
            var files = new List<string>();
            if (tree == null) return files;
            foreach (var it in tree.Items)
            {
                if (it is TreeViewItem tvi)
                    CollectCheckedFiles(tvi, files);
            }
            return files;
        }

        private static void CollectCheckedFiles(TreeViewItem node, List<string> list)
        {
            if (node.Header is StackPanel sp)
            {
                foreach (var child in sp.Children)
                {
                    if (child is CheckBox cb && cb.IsChecked == true)
                    {
                        if (node.Tag is string path && File.Exists(path))
                        {
                            list.Add(path);
                        }
                        break;
                    }
                }
            }

            foreach (var it in node.Items)
            {
                if (it is TreeViewItem t)
                    CollectCheckedFiles(t, list);
            }
        }
    }
}