using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using UnityEditor;
using UnityEditor.UIElements;
using UnityEngine.UIElements;

namespace RPGCoreCommon.DropTable.Editor
{
    public class DropTableGroupElement : VisualElement
    {
        // Property data
        private SerializedProperty _property;
        private SerializedProperty _propertyRows;
        private List<DropTableGroupRowElement> _rowElements = new();

        // Elements
        private readonly EnumField _chanceTypeField;
        private readonly VisualElement _addRowButton;
        private readonly ListView _list;

        public DropTableGroupElement(SerializedProperty property) : this()
        {
            BindProperty(property);
        }

        public DropTableGroupElement()
        {
            DropTableDrawer.groupVisualTreeAsset.CloneTree(this);
            
            SetEnabled(false);
            
            // CHANCE TYPE
            _chanceTypeField = this.Q<EnumField>("dt-chance-type");
            _chanceTypeField.RegisterValueChangedCallback(_ => Refresh());
            
            // ADD (replacement for default list button)
            _addRowButton = this.Q("dt-add-row");
            _addRowButton.RegisterCallback<ClickEvent>(_ => _list.onAdd(_list));

            // LIST
            _list = this.Q<ListView>("dt-list");
            _list.makeItem = () => new DropTableGroupRowElement();
            _list.bindItem = (element, i) =>
            {
                var rowElement = element as DropTableGroupRowElement;
                _rowElements.Add(rowElement);
                rowElement.BindProperty(_propertyRows.GetArrayElementAtIndex(i));
            };
            _list.unbindItem = (element, _) => _rowElements.Remove(element as DropTableGroupRowElement);
            _list.onAdd = _ =>
            {
                _propertyRows.arraySize++;
                _propertyRows.GetArrayElementAtIndex(_propertyRows.arraySize - 1).boxedValue = new DropTableGroupRow();
                _propertyRows.serializedObject.ApplyModifiedProperties();
                _list.RefreshItems();
            };
        }

        /// <summary>
        /// Created by <see cref="DropTableDrawer"/>. First in hierarchy <see cref="DropTableGroupElement"/>.
        /// </summary>
        internal void BindProperty(SerializedProperty property)
        {
            _property = property;
            _propertyRows = _property.FindPropertyRelative(nameof(DropTableGroup.rows));
            
            _chanceTypeField.BindProperty(_property.FindPropertyRelative(nameof(DropTableGroup.chanceType)));
            _list.BindProperty(_propertyRows);
            
            SetEnabled(true);
        }

        internal void Refresh()
        {
            var weightSum = (_property.boxedValue as DropTableGroup).rows.Sum(row => row.chance);
            _rowElements.ForEach(row => row.Refresh((ChanceTypeEnum)_chanceTypeField.value, weightSum));
        }
    }
}