using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.Json;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Extensions.Hosting;
using RainOpsMini;
using RainOpsMini.Helpers;
using RainOpsMini.Helpers.RCON;
using RainOpsMini.Models;

namespace RainOpsMini.Plugins
{
    /// <summary>
    /// 自动队伍平衡插件
    /// </summary>
    public class TeamBalancePlugin : BackgroundService, IPlugin
    {
        /// <summary>
        /// 插件名称
        /// </summary>
        public string Name => "自动队伍平衡";
        /// <summary>
        /// 插件描述
        /// </summary>
        public string Description => "当两队人数差大于设定值时，自动将优势方最后加入的玩家切换到劣势方";
        /// <summary>
        /// 插件分类
        /// </summary>
        public PluginCategory Category => PluginCategory.BasicFunction;
        /// <summary>
        /// 是否启用
        /// </summary>
        public bool IsEnabled => _config.Enabled;

        private TeamBalanceConfig _config = new TeamBalanceConfig();
        private readonly Dictionary<string, DateTime> _playerJoinTimes = new Dictionary<string, DateTime>();
        // 冷却时间，防止频繁切换或反复切换同一人
        private DateTime _lastSwitchTime = DateTime.MinValue;

        /// <summary>
        /// 自动队伍平衡配置类
        /// </summary>
        public class TeamBalanceConfig
        {
            /// <summary>
            /// 是否启用插件
            /// </summary>
            public bool Enabled { get; set; } = false;

            /// <summary>
            /// 检查间隔（秒）
            /// </summary>
            public int CheckIntervalSeconds { get; set; } = 30;

            /// <summary>
            /// 触发平衡的人数差阈值
            /// </summary>
            public int PlayerCountDifferenceThreshold { get; set; } = 3;

            /// <summary>
            /// 白名单（不被自动切换的玩家SteamID）
            /// </summary>
            public List<string> WhitelistSteamIds { get; set; } = new List<string>();

            /// <summary>
            /// 切换前是否发送警告/通知
            /// </summary>
            public bool BroadcastOnSwitch { get; set; } = true;

            /// <summary>
            /// 切换时的通知消息
            /// </summary>
            public string SwitchMessage { get; set; } = "由于队伍人数不平衡，您已被自动切换到另一方。";
        }

        /// <summary>
        /// 获取当前配置
        /// </summary>
        /// <returns>配置对象</returns>
        public object GetConfig() => _config;

        /// <summary>
        /// 重置配置为默认值
        /// </summary>
        public void ResetConfig()
        {
            _config = new TeamBalanceConfig();
        }

        /// <summary>
        /// 更新配置
        /// </summary>
        /// <param name="config">JSON配置元素</param>
        public void UpdateConfig(JsonElement config)
        {
            try
            {
                var options = new JsonSerializerOptions
                {
                    WriteIndented = true,
                    Encoder = System.Text.Encodings.Web.JavaScriptEncoder.UnsafeRelaxedJsonEscaping,
                    PropertyNameCaseInsensitive = true
                };
                _config = JsonSerializer.Deserialize<TeamBalanceConfig>(config.GetRawText(), options) ?? new TeamBalanceConfig();
            }
            catch (Exception ex)
            {
                RainOpsLog.Log($"[TeamBalance] 配置更新失败: {ex.Message}");
            }
        }

        /// <summary>
        /// 后台任务执行方法
        /// </summary>
        /// <param name="stoppingToken">取消令牌</param>
        protected override async Task ExecuteAsync(CancellationToken stoppingToken)
        {
            while (!stoppingToken.IsCancellationRequested)
            {
                try
                {
                    if (_config.Enabled && Program.Client != null && Program.Client.IsConnected)
                    {
                        await CheckAndBalanceTeams();
                    }
                }
                catch (Exception ex)
                {
                    RainOpsLog.Log($"[TeamBalance] Error: {ex.Message}");
                }

                await Task.Delay(TimeSpan.FromSeconds(_config.CheckIntervalSeconds), stoppingToken);
            }
        }

        /// <summary>
        /// 检查并平衡队伍
        /// </summary>
        private async Task CheckAndBalanceTeams()
        {
            // Rule 4: 完全拷贝一份数据
            List<PlayerInfo> players;
            lock (Program.RconCache) // 这里的lock可能不是必须的，因为RconCache.Players也是替换操作，但为了安全起见
            {
                 var cachePlayers = Program.RconCache.Players;
                 if (cachePlayers == null) return;
                 players = new List<PlayerInfo>(cachePlayers);
            }

            if (players.Count == 0) return;

            // 更新加入时间
            var currentSteamIds = players.Select(p => p.SteamId).ToHashSet();
            
            // 移除离开的玩家
            var leftPlayers = _playerJoinTimes.Keys.Where(k => !currentSteamIds.Contains(k)).ToList();
            foreach (var left in leftPlayers)
            {
                _playerJoinTimes.Remove(left);
            }

            // 添加新玩家
            foreach (var p in players)
            {
                if (!_playerJoinTimes.ContainsKey(p.SteamId))
                {
                    _playerJoinTimes[p.SteamId] = DateTime.Now;
                }
            }

            // 计算队伍人数
            var team1 = players.Where(p => p.TeamId == 1).ToList();
            var team2 = players.Where(p => p.TeamId == 2).ToList();

            int count1 = team1.Count;
            int count2 = team2.Count;
            int diff = Math.Abs(count1 - count2);

            if (diff > _config.PlayerCountDifferenceThreshold)
            {
                // 确定人数较多的队伍
                int largerTeamId = count1 > count2 ? 1 : 2;
                int smallerTeamId = count1 > count2 ? 2 : 1;
                var largerTeamPlayers = count1 > count2 ? team1 : team2;

                // 寻找待切换的候选人
                // 过滤白名单
                var candidates = largerTeamPlayers
                    .Where(p => !_config.WhitelistSteamIds.Contains(p.SteamId))
                    .ToList();

                if (candidates.Count > 0)
                {
                    // 按加入时间倒序排序（最新加入的优先）
                    // 如果加入时间相同（如初始加载），使用ID倒序作为打破平局的依据（假设ID越大越新）
                    var target = candidates
                        .OrderByDescending(p => _playerJoinTimes.TryGetValue(p.SteamId, out var time) ? time : DateTime.MinValue)
                        .ThenByDescending(p => p.Id)
                        .FirstOrDefault();

                    if (target != null)
                    {
                        await PerformSwitch(target, smallerTeamId);
                    }
                }
            }
        }

        /// <summary>
        /// 执行玩家切换队伍操作
        /// </summary>
        /// <param name="player">目标玩家</param>
        /// <param name="targetTeamId">目标队伍ID</param>
        private async Task PerformSwitch(PlayerInfo player, int targetTeamId)
        {
            if (_config.BroadcastOnSwitch)
            {
                // 通知玩家
                // AdminWarn <NameOrSteamId> <Reason>
                string warnCmd = $"AdminWarn \"{player.SteamId}\" {_config.SwitchMessage}";
                await Program.Client.SendCommandAsync(warnCmd);
                
                // 可选：全服广播
                // string broadcastCmd = $"AdminBroadcast balanced {player.Name} to Team {targetTeamId}";
                // await Program.Client.SendCommandAsync(broadcastCmd);
            }

            // 执行切换命令
            // Command: AdminForceTeamChange <NameOrSteamId>
            // 使用 SteamId 更安全
            string command = $"AdminForceTeamChange \"{player.SteamId}\"";
            RainOpsLog.Log($"[TeamBalance] Switching player {player.Name} ({player.SteamId}) to Team {targetTeamId}");
            
            await Program.Client.SendCommandAsync(command);
        }
    }
}