using System;
using System.Collections.Generic;
using System.Linq;
using GameFix.PaoDeKuaiF;
using GameFix.Poker;
using GameMessage;
using GameMessage.PaoDeKuaiF;
using Microsoft.ML.OnnxRuntime;
using Microsoft.ML.OnnxRuntime.Tensors;

namespace PdkFriendServer.Logic
{
    /// <summary>
    /// NeuralBot v1 — 加载 ONNX 模型做决策的 Bot。
    /// 状态编码与 Python trainer 完全一致：15 rank × 4 suit × 7 channel → 420 float。
    ///
    /// 用法：PdkGameMain.InitBots() 中替换部分 bot 为 NeuralBot。
    /// 训练：Python trainer → 导出 ONNX → 放 model.onnx → C# 加载。
    /// </summary>
    public class NeuralBot : IPdkBot
    {
        private readonly InferenceSession _session;
        private readonly Random _rng;
        private readonly CardTracker _tracker = new CardTracker();
        private readonly float _epsilon; // 探索率

        // 状态编码常量
        private static readonly int[] Ranks = { 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 16 };
        private const int NumRanks = 13;
        private const int NumSuits = 4;
        private const int NumChannels = 7;
        private const int InputDim = TrainingCollector.InputDim; // 364
        private const int OutputDim = 1; // V(state) = P(win)

        public NeuralBot(string modelPath = "model.onnx", float epsilon = 0.05f)
        {
            var options = new SessionOptions();
            options.LogSeverityLevel = OrtLoggingLevel.ORT_LOGGING_LEVEL_ERROR;
            _session = new InferenceSession(modelPath, options);
            _rng = new Random();
            _epsilon = epsilon;
        }

        public bool DecideBaoZhuang(PdkBotView view)
        {
            // Neural model 暂不参与包庄决策，沿用 ISMCTS 逻辑
            _tracker.Update(view);
            int minPlays = HandOptimizer.MinPlays(view.MyHand);
            if (minPlays >= 7) return false;
            return minPlays <= 3; // 极简：手牌极好才包
        }

        public PlayOutCardPdkF DecidePlay(PdkBotView view)
        {
            _tracker.Update(view);
            var hand = view.MyHand;
            if (hand.Length == 0) return Pass(view);

            // 1. 获取合法出牌
            bool isFirstPlay = view.MaxPlayCard.GameNum <= 0;
            var tips = PdkCardAlgorithm.GetTipCard(view.MaxPlayCard, hand, null, view.Rule.AAAIsZhaDan);
            var candidates = new List<(PlayOutCardPdkF play, int actionIdx)>();

            if (tips != null)
            {
                foreach (var tip in tips)
                {
                    int rank = tip[0].GameNum;
                    int idx = RankToIdx(rank);
                    candidates.Add((MakePlay(tip, view.MyPos), idx));
                }
            }

            // 新轮次补多牌方案
            if (isFirstPlay)
                AddMultiCardCandidates(hand, view.MyPos, candidates);

            if (!isFirstPlay)
                candidates.Add((Pass(view), OutputDim - 1)); // pass = last index

            if (candidates.Count == 0) return Pass(view);
            if (candidates.Count == 1) return candidates[0].play;

            // 2. ε-greedy 探索
            if (_rng.NextDouble() < _epsilon)
                return candidates[_rng.Next(candidates.Count)].play;

            // 3. V-learning: 对每个候选，编码出牌后的状态，选 V 值最高的
            float bestV = float.MinValue;
            int bestIdx = 0;
            var debugVals = new System.Text.StringBuilder();
            for (int i = 0; i < Math.Min(candidates.Count, 8); i++)
            {
                var play = candidates[i].play;
                var afterHand = play.Ids != null && play.Ids.Length > 0
                    ? hand.Where(c => !play.Ids.Contains(c.ID)).ToArray()
                    : hand;
                var afterState = EncodeAfterPlay(view, afterHand, play);
                var v = RunInference(afterState);
                float val = v.Length > 0 ? v[0] : 0;
                
                string label = play.Ids != null && play.Ids.Length > 0
                    ? $"{play.Ids.Length}c r{play.GameNum}" : "pass";
                debugVals.Append($" {label}={val:F2}");

                if (val > bestV) { bestV = val; bestIdx = i; }
            }
            // 继续评估剩余候选（不输出日志）
            for (int i = 8; i < candidates.Count; i++)
            {
                var play = candidates[i].play;
                var afterHand = play.Ids != null && play.Ids.Length > 0
                    ? hand.Where(c => !play.Ids.Contains(c.ID)).ToArray()
                    : hand;

                // 编码出牌后状态
                var afterState = EncodeAfterPlay(view, afterHand, play);
                var v = RunInference(afterState);
                float val = v.Length > 0 ? v[0] : 0;

                if (val > bestV)
                {
                    bestV = val;
                    bestIdx = i;
                }
            }

            var chosen = candidates[bestIdx];
            bool isPass = chosen.play.Ids == null || chosen.play.Ids.Length == 0;
            Console.WriteLine($"[NeuralBot pos{view.MyPos}] {candidates.Count}c → "
                            + $"{(isPass ? "pass" : $"{chosen.play.Ids?.Length ?? 1}c r{chosen.play.GameNum}")} V={bestV:F3}"
                            + (debugVals.Length > 0 ? $" [{debugVals}]" : ""));
            TrainingCollector.Record(view, _tracker,
                isPass ? 13 : TrainingCollector.RankToIdx(chosen.play.GameNum), view.MyPos - 1);
            return chosen.play;
        }

        // 编码出牌后状态：模拟出牌后的 PdkBotView
        private float[] EncodeAfterPlay(PdkBotView view, TCardInfoPdkF[] afterHand, PlayOutCardPdkF play)
        {
            var playedIds = play.Type != CardType1.None && play.Ids != null
                ? play.Ids.Select(id => (int)id).ToArray() : null;
            return TrainingCollector.EncodeAfterPlay(view, _tracker, afterHand, playedIds);
        }

        // ---- 状态编码（与 Python encode_game_state 一致）----

        private float[] EncodeState(PdkBotView view)
        {
            var state = new float[InputDim]; // 7 × 13 × 4 = 364

            // ch0: 我的手牌
            foreach (var c in view.MyHand)
            {
                if (c.GameState != 1) continue;
                int ri = RankToIdx(c.GameNum);
                int si = SuitToIdx(c.ID);
                if (ri >= 0 && si >= 0)
                    state[ChOffset(0) + ri * NumSuits + si] = 1.0f;
            }

            // ch1: 已出牌 — 通过 card tracker 的 seen cards
            var seenIds = GetSeenCardIds(view);
            foreach (var id in seenIds)
            {
                int ri = RankToIdx(IdToGameNum(id));
                int si = SuitToIdx(id);
                if (ri >= 0 && si >= 0)
                    state[ChOffset(1) + ri * NumSuits + si] = 1.0f;
            }

            // ch2: 我的手牌数量
            int myCount = view.MyHand.Count(c => c.GameState == 1);
            int c2Slot = myCount % NumRanks;
            state[ChOffset(2) + c2Slot * NumSuits + 0] = (float)myCount / 16.0f;

            // ch3: 下家剩余
            int opp1 = view.MyPos % 3;
            int c1 = view.ShenYuCard[opp1];
            state[ChOffset(3) + (c1 % NumRanks) * NumSuits + 0] = (float)c1 / 16.0f;

            // ch4: 上家剩余
            int opp2 = (view.MyPos + 1) % 3;
            int c2 = view.ShenYuCard[opp2];
            state[ChOffset(4) + (c2 % NumRanks) * NumSuits + 0] = (float)c2 / 16.0f;

            // ch5: 当前位置
            state[ChOffset(5) + (view.MyPos % NumRanks) * NumSuits + 0] = 1.0f;

            // ch6: last_play rank
            if (view.MaxPlayCard.GameNum > 0 && view.MaxPlayCard.Pos != view.MyPos)
            {
                int lr = RankToIdx(view.MaxPlayCard.GameNum);
                if (lr >= 0)
                    state[ChOffset(6) + lr * NumSuits + 0] = 1.0f;
            }

            return state;
        }

        private float[] RunInference(float[] input)
        {
            var tensor = new DenseTensor<float>(input, new[] { 1, InputDim });
            var inputs = new List<NamedOnnxValue> { NamedOnnxValue.CreateFromTensor("state", tensor) };
            using var results = _session.Run(inputs);
            var output = results.First().AsTensor<float>();
            return output.ToArray();
        }

        // ---- 辅助 ----

        private static int RankToIdx(int gameNum) => gameNum switch
        {
            3 => 0, 4 => 1, 5 => 2, 6 => 3, 7 => 4, 8 => 5, 9 => 6,
            10 => 7, 11 => 8, 12 => 9, 13 => 10, 14 => 11, 16 => 12,
            _ => -1
        };

        private static int SuitToIdx(int id)
        {
            // ID = (suit-1)*13 + n, suit 1-4
            int suit = (id - 1) / 13; // 0-3
            return suit >= 0 && suit < 4 ? suit : -1;
        }

        private static int IdToGameNum(int id)
        {
            int n = (id - 1) % 13 + 1; // 1-13
            return n == 1 ? 14 : n == 2 ? 16 : n;
        }

        private HashSet<int> GetSeenCardIds(PdkBotView view)
        {
            var seen = new HashSet<int>();
            // Track played cards through view: all hands that have appeared on table
            if (view.MaxPlayCard.Ids != null)
                foreach (var id in view.MaxPlayCard.Ids) seen.Add(id);
            // Also track from our own played cards (cards not in my hand anymore)
            return seen;
        }

        private static int ChOffset(int ch) => ch * NumRanks * NumSuits;

        // ---- 多牌候选（精简版，复用 IsmctsBot 逻辑）----

        private void AddMultiCardCandidates(TCardInfoPdkF[] hand, int pos,
            List<(PlayOutCardPdkF play, int actionIdx)> candidates)
        {
            // 对子
            foreach (var g in hand.Where(c => c.GameState == 1).GroupBy(c => c.GameNum).Where(g => g.Count() >= 2))
            {
                var pair = g.Take(2).ToList();
                candidates.Add((MakePlay(pair, pos), RankToIdx(pair[0].GameNum)));
            }
            // 三张
            foreach (var g in hand.Where(c => c.GameState == 1).GroupBy(c => c.GameNum).Where(g => g.Count() >= 3))
            {
                var trip = g.Take(3).ToList();
                var rem = hand.Where(c => c.GameState == 1 && c.GameNum != g.Key).ToList();
                if (rem.Count >= 2)
                {
                    // 优先带对子
                    var pair = rem.GroupBy(c => c.GameNum).Where(x => x.Count() >= 2).OrderBy(x => x.Key).FirstOrDefault();
                    var attach = pair != null ? pair.Take(2).ToList() : rem.OrderBy(c => c.GameNum).Take(2).ToList();
                    candidates.Add((MakePlay(trip.Concat(attach).ToList(), pos), RankToIdx(trip[0].GameNum)));
                }
            }
            // 顺子
            var straights = PokerLogic.GetShunZi<TCardInfoPdkF>(hand);
            if (straights != null)
                foreach (var s in straights)
                {
                    var cards = s.ToList();
                    candidates.Add((MakePlay(cards, pos), RankToIdx(cards[0].GameNum)));
                }
            // 炸弹
            if (PokerLogic.GetPlayZhaDans<TCardInfoPdkF>(hand, out var bombs) && bombs != null)
                foreach (var b in bombs)
                {
                    var cards = b.ToList();
                    candidates.Add((MakePlay(cards, pos), RankToIdx(cards[0].GameNum)));
                }
        }

        private static PlayOutCardPdkF MakePlay(List<TCardInfoPdkF> cards, int pos)
            => new PlayOutCardPdkF { Pos = (byte)pos, GameNum = cards[0].GameNum, Ids = cards.Select(c => c.ID).ToArray(), Type = CardType1.None };

        private static PlayOutCardPdkF Pass(PdkBotView v)
            => new PlayOutCardPdkF { Pos = (byte)v.MyPos, Type = CardType1.None };

        public void Dispose() => _session?.Dispose();
    }
}