using UnityEngine;
using System.Threading;
using CharacterSystem;

public class Bot : BasePlayer, IGamePlayer
{
    [Header("Movement Settings")]
    [SerializeField] private float prepareSpeed;
    [SerializeField] private float moveSpeed;

    [Header("Bot Settings")]
    [SerializeField] private DifficultyPreset difficultyPreset;
    [SerializeField] private bool useDummyBots = false;
    [SerializeField] private float minThinkingTime = 1f;
    [SerializeField, Min(0f)] private float _candidatePauseDuration = 0.35f;

    public DifficultyPreset dummyPreset;

    // State
    private PlayerState state = PlayerState.Sleep;
    private Chip currentChip;
    private int[] availableColumns;
    private int selectedColumnIndex;

    // Movement targets
    private Vector2 stickedTargetPosition;
    private Vector2 dropTargetPosition;

    // Thinking
    private Thread calculationThread;
    private int calculatedColumn = -1;
    private float thinkingStartTime;
    private float _requiredThinkingTime;
    private bool isThinkingComplete = false;
    private DifficultyPreset _activeDifficultyPreset;
    private bool _useStrongSolver;

    private int[] _thinkingCandidates;
    private int _thinkingCandidateIndex;
    private float _candidatePauseUntil;
    private bool _isVisitingCandidates;

    private int droppedRow, droppedColumn;

    public event System.Action<int, int> OnChipDropped;

    private int SelectedColumn => availableColumns[selectedColumnIndex];
    public bool ControlsEnabled { get; set; } = true;

    public void PrepareChip()
    {
        SetState(PlayerState.Preparing);
        CacheAvailableColumns();
        CreateChip();
        SetInitialChipPosition();
    }

    public void Sleep()
    {
        SetState(PlayerState.Sleep);
        currentChip = null;
        availableColumns = null;
        StopThinking();
    }

    public void CancelTurn()
    {
        StopThinking();

        if (currentChip != null)
        {
            if (state == PlayerState.Dropping)
                currentChip.transform.position = dropTargetPosition;
            else
                ChipPool.Instance.Release(currentChip);
        }

        currentChip = null;
        availableColumns = null;
        SetState(PlayerState.Sleep);
    }

    public void UpdateControls()
    {
        switch (state)
        {
            case PlayerState.Preparing:
                UpdatePreparing();
                break;
            case PlayerState.Thinking:
                UpdateThinking();
                break;
            case PlayerState.Moving:
                UpdateMoving();
                break;
            case PlayerState.Dropping:
                UpdateDropping();
                break;
            case PlayerState.Sleep:
                break;
        }
    }


    private void UpdatePreparing()
    {
        // Движение сверху вниз к stickedTargetPosition (без оффсета)
        if (currentChip.MoveToLinear(stickedTargetPosition, prepareSpeed))
        {
            StartThinking();
        }
    }

    private void UpdateThinking()
    {
        if (!isThinkingComplete)
            return;

        if (!_isVisitingCandidates)
        {
            StartCandidateVisit();
            return;
        }

        if (Time.time < _candidatePauseUntil)
            return;

        if (_thinkingCandidateIndex < _thinkingCandidates.Length - 1)
        {
            _thinkingCandidateIndex++;
            MoveToCandidate(_thinkingCandidates[_thinkingCandidateIndex]);
            return;
        }

        if (Time.time - thinkingStartTime >= _requiredThinkingTime)
            PerformDrop();
    }

    private void UpdateMoving()
    {
        if (currentChip.MoveToLinear(stickedTargetPosition, moveSpeed))
        {
            SetState(PlayerState.Thinking);
            _candidatePauseUntil = Time.time + _candidatePauseDuration;
        }
    }

    private void UpdateDropping()
    {
        if (currentChip.MoveToAccelerated(dropTargetPosition))
        {
            SetState(PlayerState.Sleep);
            OnChipDropped?.Invoke(droppedColumn, droppedRow);
        }
    }

    private void StartThinking()
    {
        SetState(PlayerState.Thinking);
        isThinkingComplete = false;
        calculatedColumn = -1;
        thinkingStartTime = Time.time;
        _thinkingCandidates = null;
        _thinkingCandidateIndex = 0;
        _candidatePauseUntil = 0f;
        _isVisitingCandidates = false;
        CacheDifficulty();

        StopThinking();
        calculationThread = new Thread(CalculateBestMove);
        calculationThread.Start();
    }

    private void StopThinking()
    {
        if (calculationThread != null && calculationThread.IsAlive)
        {
            calculationThread.Abort();
            calculationThread = null;
        }
    }

    private void CalculateBestMove()
    {
        try
        {
            Solver.SetPreset(_activeDifficultyPreset);

            if (_useStrongSolver)
                calculatedColumn = SolverV2.FindBestMove(board.GridToTeam(), team);
            else
                calculatedColumn = Solver.FindBestMove(board.GridToTeam(), team);

            isThinkingComplete = true;
        }
        catch (ThreadAbortException) { }
        catch (System.Exception e)
        {
            Debug.LogError($"Bot calculation error: {e.Message}");
        }
    }

    private void StartCandidateVisit()
    {
        _thinkingCandidates = BuildThinkingCandidates();
        _thinkingCandidateIndex = 0;
        _isVisitingCandidates = true;
        MoveToCandidate(_thinkingCandidates[_thinkingCandidateIndex]);
    }

    private void MoveToCandidate(int column)
    {
        int targetIndex = System.Array.IndexOf(availableColumns, column);
        if (targetIndex == -1)
        {
            Debug.LogWarning($"Column {column} is not available!");
            return;
        }

        if (selectedColumnIndex == targetIndex)
        {
            _candidatePauseUntil = Time.time + _candidatePauseDuration;
            return;
        }

        selectedColumnIndex = targetIndex;
        SoundManager.instance?.PlayColumnSelectionSound();
        UpdateTargetPositionX(board.GetStickedPosition(SelectedColumn).x);
        SetState(PlayerState.Moving);
    }

    private int[] BuildThinkingCandidates()
    {
        int alternativeColumn = FindAlternativeCandidate(calculatedColumn);
        return alternativeColumn >= 0
            ? new[] { alternativeColumn, calculatedColumn }
            : new[] { calculatedColumn };
    }

    private int FindAlternativeCandidate(int finalColumn)
    {
        Team[,] grid = board.GridToTeam();
        Team opponent = team == Team.Player1 ? Team.Player2 : Team.Player1;
        int bestColumn = -1;
        float bestScore = float.NegativeInfinity;
        float boardCenter = (board.Columns - 1) * 0.5f;

        foreach (int column in availableColumns)
        {
            if (column == finalColumn)
                continue;

            int row = board.GetLowestEmptyRow(column);
            int attackScore = EvaluatePlacement(grid, row, column, team);
            int blockScore = EvaluatePlacement(grid, row, column, opponent);
            float centerPenalty = Mathf.Abs(column - boardCenter);
            float score = attackScore * 2f + blockScore * 1.5f - centerPenalty;

            if (score > bestScore)
            {
                bestScore = score;
                bestColumn = column;
            }
        }

        return bestColumn;
    }

    private int EvaluatePlacement(Team[,] grid, int row, int column, Team evaluatedTeam)
    {
        grid[row, column] = evaluatedTeam;

        int longestLine = Mathf.Max(
            GetLineLength(grid, row, column, evaluatedTeam, 1, 0),
            GetLineLength(grid, row, column, evaluatedTeam, 0, 1),
            GetLineLength(grid, row, column, evaluatedTeam, 1, 1),
            GetLineLength(grid, row, column, evaluatedTeam, 1, -1));

        grid[row, column] = Team.None;
        return longestLine >= 4 ? 100 + longestLine : longestLine * longestLine;
    }

    private int GetLineLength(Team[,] grid, int row, int column, Team evaluatedTeam, int rowStep, int columnStep)
    {
        return 1
            + CountDirection(grid, row, column, evaluatedTeam, rowStep, columnStep)
            + CountDirection(grid, row, column, evaluatedTeam, -rowStep, -columnStep);
    }

    private int CountDirection(Team[,] grid, int row, int column, Team evaluatedTeam, int rowStep, int columnStep)
    {
        int count = 0;
        int currentRow = row + rowStep;
        int currentColumn = column + columnStep;

        while (currentRow >= 0 && currentRow < grid.GetLength(0) &&
               currentColumn >= 0 && currentColumn < grid.GetLength(1) &&
               grid[currentRow, currentColumn] == evaluatedTeam)
        {
            count++;
            currentRow += rowStep;
            currentColumn += columnStep;
        }

        return count;
    }

    private void PerformDrop()
    {
        dropTargetPosition = board.GetTargetPosition(SelectedColumn);

        droppedColumn = SelectedColumn;
        droppedRow = board.GetLowestEmptyRow(SelectedColumn);

        board.DropChip(currentChip, SelectedColumn);
        SetState(PlayerState.Dropping);
    }

    private void CacheAvailableColumns()
    {
        availableColumns = board.GetNonFullColumns();
        selectedColumnIndex = availableColumns.Length / 2;
    }

    private void CreateChip()
    {
        if (CharactersController.HasActiveCharacter && CharactersController.CurrentCharacter.visualModule.chipImage != null)
            chipSprite = CharactersController.CurrentCharacter.visualModule.chipImage;

        currentChip = ChipPool.Instance.GetConfigured(chipSprite, team);
    }

    private void CacheDifficulty()
    {
        DifficultyPreset currentPreset = difficultyPreset;
        _requiredThinkingTime = minThinkingTime;

        if (useDummyBots)
        {
            currentPreset = dummyPreset;
        }
        else if (GameManager.Instance != null &&
                 GameManager.Instance.gameMode == GameMode.pve &&
                 CharactersController.HasActiveCharacter)
        {
            DifficultyModule difficultyModule = CharactersController.CurrentCharacter.difficultyModule;
            currentPreset = difficultyModule.GetCurrentPreset();
            _requiredThinkingTime = difficultyModule.ThinkTime;
        }

        _activeDifficultyPreset = currentPreset != null && board != null
            ? currentPreset.GetPreset(board.MovesCount)
            : currentPreset;

        bool isLastCharacter = CharactersController.HasActiveCharacter &&
                               CharactersController.CharacterIndex == CharactersController.CharactersAmount - 1;
        bool isHardDifficulty = SettingsManager.GetString(SettingKey.DIFFICULTY) == "Сложная";
        bool isEarningMode = SettingsManager.GetString(SettingKey.DIFFICULTY_MODE) == "Заработок";
        _useStrongSolver = isLastCharacter && (isHardDifficulty || isEarningMode);
    }

    private void SetInitialChipPosition()
    {
        // Начальная позиция – сверху с оффсетом
        stickedTargetPosition = board.GetStickedPosition(SelectedColumn);
        currentChip.transform.position = stickedTargetPosition + Vector2.up * 5f;
    }

    private void SetState(PlayerState newState) => state = newState;

    // Обновляет только X целевой позиции, Y остаётся неизменным
    private void UpdateTargetPositionX(float newX)
    {
        stickedTargetPosition = new Vector2(newX, stickedTargetPosition.y);
    }

    private enum PlayerState
    {
        Sleep,
        Preparing,
        Thinking,
        Moving,
        Dropping
    }
}