using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;

namespace MvdLiteSnoop
{
    public static class DataGridMultiEditSyncBehavior
    {
        public static readonly DependencyProperty EnableMultiEditSyncProperty =
            DependencyProperty.RegisterAttached(
                "EnableMultiEditSync",
                typeof(bool),
                typeof(DataGridMultiEditSyncBehavior),
                new PropertyMetadata(false, OnEnableMultiEditSyncChanged));

        public static void SetEnableMultiEditSync(DependencyObject obj, bool value) =>
            obj.SetValue(EnableMultiEditSyncProperty, value);

        public static bool GetEnableMultiEditSync(DependencyObject obj) =>
            (bool)obj.GetValue(EnableMultiEditSyncProperty);

        private static void OnEnableMultiEditSyncChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            if (d is DataGrid dg)
            {
                if ((bool)e.NewValue)
                    dg.PreparingCellForEdit += Dg_PreparingCellForEdit;
                else
                    dg.PreparingCellForEdit -= Dg_PreparingCellForEdit;
            }
        }

        private static void Dg_PreparingCellForEdit(object sender, DataGridPreparingCellForEditEventArgs e)
        {
            var dg = (DataGrid)sender;
            var column = e.Column;
            if (column.IsReadOnly) return;

            // 获取属性名
            var propName = column.SortMemberPath;
            if (string.IsNullOrWhiteSpace(propName))
                propName = GetBindingPath(column);

            if (string.IsNullOrEmpty(propName)) return;

            var editingElement = e.EditingElement;

            // 根据不同控件类型绑定即时事件
            if (editingElement is TextBox tb)
            {
                tb.TextChanged -= Handler;
                tb.TextChanged += Handler;
            }
            else if (editingElement is CheckBox cb)
            {
                cb.Checked -= Handler;
                cb.Unchecked -= Handler;
                cb.Checked += Handler;
                cb.Unchecked += Handler;
            }
            else if (editingElement is ComboBox combo)
            {
                combo.SelectionChanged -= Handler;
                combo.SelectionChanged += Handler;
            }

            void Handler(object s, EventArgs args)
            {
                var rowItem = e.Row.Item;
                var prop = rowItem.GetType().GetProperty(propName, BindingFlags.Public | BindingFlags.Instance);
                if (prop == null || !prop.CanWrite) return;

                var newValue = prop.GetValue(rowItem);

                foreach (var sel in dg.SelectedItems)
                {
                    if (ReferenceEquals(sel, rowItem)) continue;

                    var selProp = sel.GetType().GetProperty(propName, BindingFlags.Public | BindingFlags.Instance);
                    if (selProp != null && selProp.CanWrite)
                    {
                        try
                        {
                            if (selProp.PropertyType.IsAssignableFrom(prop.PropertyType))
                            {
                                selProp.SetValue(sel, newValue);
                            }
                            else
                            {
                                var converted = Convert.ChangeType(newValue, selProp.PropertyType);
                                selProp.SetValue(sel, converted);
                            }
                        }
                        catch
                        {
                            // 类型不兼容时忽略
                        }
                    }
                }
            }
        }

        private static string GetBindingPath(DataGridColumn column)
        {
            if (column is DataGridBoundColumn boundCol)
            {
                if (boundCol.Binding is Binding binding)
                    return binding.Path?.Path;
            }
            else if (column is DataGridComboBoxColumn comboCol)
            {
                if (comboCol.SelectedItemBinding is Binding binding)
                    return binding.Path?.Path;
                if (comboCol.SelectedValueBinding is Binding binding2)
                    return binding2.Path?.Path;
            }
            return null;
        }
    }
}