#nullable enable
using System.Collections.Generic;
using System.Linq;

namespace UVC.UIToolkit
{
    /// <summary>
    /// 다중 선택 드롭다운 속성 데이터 클래스입니다.
    /// UI는 UTKMultiSelectDropdownPropertyItemView에서 담당합니다.
    /// </summary>
    public class UTKMultiSelectDropdownPropertyItem : UTKPropertyItemBase<List<string>>
    {
        #region Fields
        private List<string> _choices;
        #endregion

        #region Properties
        /// <summary>속성 타입</summary>
        public override UTKPropertyType PropertyType => UTKPropertyType.MultiSelectDropdownList;

        /// <summary>선택 가능한 항목 목록</summary>
        public List<string> Choices
        {
            get => _choices;
            set => _choices = value ?? new List<string>();
        }

        /// <summary>선택된 인덱스 목록</summary>
        public List<int> SelectedIndices
        {
            get
            {
                if (Value == null || Value.Count == 0)
                    return new List<int>();

                return Value
                    .Select(v => _choices.IndexOf(v))
                    .Where(i => i >= 0)
                    .OrderBy(i => i)
                    .ToList();
            }
        }
        #endregion

        #region Constructor
        /// <summary>
        /// 다중 선택 드롭다운 속성을 생성합니다.
        /// </summary>
        /// <param name="id">고유 ID</param>
        /// <param name="name">표시 이름</param>
        /// <param name="choices">선택 항목 목록</param>
        /// <param name="initialValues">초기 선택 값 목록</param>
        /// <param name="isReadOnly">읽기 전용 여부</param>
        public UTKMultiSelectDropdownPropertyItem(
            string id,
            string name,
            List<string> choices,
            List<string>? initialValues = null,
            bool isReadOnly = false)
            : base(id, name, initialValues ?? new List<string>())
        {
            _choices = choices ?? new List<string>();

            // initialValues가 유효한지 확인하고 필터링
            if (initialValues != null && initialValues.Count > 0)
            {
                var validValues = initialValues.Where(v => _choices.Contains(v)).ToList();
                Value = validValues;
            }

            IsReadOnly = isReadOnly;
        }

        /// <summary>
        /// 다중 선택 드롭다운 속성을 생성합니다 (인덱스 기반).
        /// </summary>
        /// <param name="id">고유 ID</param>
        /// <param name="name">표시 이름</param>
        /// <param name="choices">선택 항목 목록</param>
        /// <param name="selectedIndices">초기 선택 인덱스 목록</param>
        /// <param name="isReadOnly">읽기 전용 여부</param>
        public UTKMultiSelectDropdownPropertyItem(
            string id,
            string name,
            IEnumerable<string> choices,
            IEnumerable<int>? selectedIndices = null,
            bool isReadOnly = false)
            : base(id, name, new List<string>())
        {
            _choices = choices?.ToList() ?? new List<string>();

            if (selectedIndices != null)
            {
                var validValues = selectedIndices
                    .Where(i => i >= 0 && i < _choices.Count)
                    .Select(i => _choices[i])
                    .ToList();
                Value = validValues;
            }

            IsReadOnly = isReadOnly;
        }
        #endregion

        #region Public Methods
        /// <summary>선택 항목 추가</summary>
        public void AddChoice(string choice)
        {
            if (!_choices.Contains(choice))
            {
                _choices.Add(choice);
            }
        }

        /// <summary>선택 항목 제거</summary>
        public bool RemoveChoice(string choice)
        {
            bool removed = _choices.Remove(choice);
            if (removed && Value != null && Value.Contains(choice))
            {
                // 값 목록에서도 제거
                var newValue = Value.Where(v => v != choice).ToList();
                Value = newValue;
            }
            return removed;
        }

        /// <summary>인덱스로 선택 설정</summary>
        public void SetSelectedIndices(List<int> indices)
        {
            var validValues = indices
                .Where(i => i >= 0 && i < _choices.Count)
                .Select(i => _choices[i])
                .Distinct()
                .ToList();
            Value = validValues;
        }

        /// <summary>값으로 선택 설정</summary>
        public void SetSelectedValues(List<string> values)
        {
            var validValues = values
                .Where(v => _choices.Contains(v))
                .Distinct()
                .ToList();
            Value = validValues;
        }

        /// <summary>모든 항목 선택</summary>
        public void SelectAll()
        {
            Value = new List<string>(_choices);
        }

        /// <summary>모든 선택 해제</summary>
        public void ClearSelection()
        {
            Value = new List<string>();
        }
        #endregion
    }
}