using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.ComponentModel;
using System.Runtime.CompilerServices;

namespace AI.Models.SpecialMessages
{
    /// <summary>
    /// 表示一条「必需列 -> 预览列」的匹配项，用于绑定显示。
    /// </summary>
    public class ColumnMappingItem : INotifyPropertyChanged
    {
        private string _requiredColumn = string.Empty;
        private string _matchedColumn = string.Empty;

        /// <summary>必需列名称</summary>
        public string RequiredColumn
        {
            get => _requiredColumn;
            set => SetProperty(ref _requiredColumn, value ?? string.Empty);
        }

        /// <summary>匹配到的预览列名称（未匹配时可为空）</summary>
        public string MatchedColumn
        {
            get => _matchedColumn;
            set => SetProperty(ref _matchedColumn, value ?? string.Empty);
        }

        public event PropertyChangedEventHandler? PropertyChanged;
        protected void OnPropertyChanged([CallerMemberName] string? propertyName = null) =>
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        protected bool SetProperty<T>(ref T field, T value, [CallerMemberName] string? propertyName = null)
        {
            if (EqualityComparer<T>.Default.Equals(field, value)) return false;
            field = value;
            OnPropertyChanged(propertyName);
            return true;
        }
    }

    /// <summary>
    /// 列头匹配特殊消息 - 用于在聊天流中展示「必需列」与「预览列」及其匹配关系。
    /// </summary>
    public class ColumnMatchMessage : ISpecialMessage, INotifyPropertyChanged
    {
        private string _title = "列头匹配";

        /// <summary>消息唯一标识符</summary>
        public string Id { get; set; } = Guid.NewGuid().ToString();

        /// <summary>类型名称</summary>
        public string TypeName => "ColumnMatch";

        /// <summary>不需要实时更新</summary>
        public bool IsLive => false;

        /// <summary>标题（如「列头匹配」）</summary>
        public string Title
        {
            get => _title;
            set => SetProperty(ref _title, value ?? string.Empty);
        }

        /// <summary>必需列名称列表</summary>
        public ObservableCollection<string> RequiredColumns { get; } = new ObservableCollection<string>();

        /// <summary>预览列（可用列）名称列表</summary>
        public ObservableCollection<string> PreviewColumns { get; } = new ObservableCollection<string>();

        /// <summary>匹配关系：必需列 -> 匹配的预览列</summary>
        public ObservableCollection<ColumnMappingItem> Mappings { get; } = new ObservableCollection<ColumnMappingItem>();

        public event PropertyChangedEventHandler? PropertyChanged;
        protected void OnPropertyChanged([CallerMemberName] string? propertyName = null) =>
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        protected bool SetProperty<T>(ref T field, T value, [CallerMemberName] string? propertyName = null)
        {
            if (EqualityComparer<T>.Default.Equals(field, value)) return false;
            field = value;
            OnPropertyChanged(propertyName);
            return true;
        }

        /// <summary>设置必需列与预览列，并清空匹配关系</summary>
        public void SetColumns(IEnumerable<string> requiredColumns, IEnumerable<string> previewColumns)
        {
            RequiredColumns.Clear();
            foreach (var c in requiredColumns ?? Array.Empty<string>())
                RequiredColumns.Add(c ?? string.Empty);
            PreviewColumns.Clear();
            foreach (var c in previewColumns ?? Array.Empty<string>())
                PreviewColumns.Add(c ?? string.Empty);
            Mappings.Clear();
        }

        /// <summary>设置匹配关系（必需列 -> 预览列），会清空并替换当前 Mappings</summary>
        public void SetMappings(IEnumerable<KeyValuePair<string, string>> mappings)
        {
            Mappings.Clear();
            if (mappings == null) return;
            foreach (var kv in mappings)
            {
                Mappings.Add(new ColumnMappingItem
                {
                    RequiredColumn = kv.Key ?? string.Empty,
                    MatchedColumn = kv.Value ?? string.Empty,
                });
            }
        }
    }
}