package fr.iut_fbleau.Bot;

import fr.iut_fbleau.Avalam.AvalamBoard;
import fr.iut_fbleau.Avalam.AvalamPly;
import fr.iut_fbleau.Avalam.Color;
import fr.iut_fbleau.Avalam.Tower;
import fr.iut_fbleau.GameAPI.AbstractGamePlayer;
import fr.iut_fbleau.GameAPI.AbstractPly;
import fr.iut_fbleau.GameAPI.IBoard;
import fr.iut_fbleau.GameAPI.Player;
import fr.iut_fbleau.GameAPI.Result;

import java.util.*;

/**
 * Bot "Divin" (fort) pour Avalam.
 *
 *
 * Objectif : trop fort. */
public class DivineBot{
    private final Player me;
    private final int maxDepth;
    private final Random rng = new Random();

    public DivineBot(Player p, int maxDepth) {
        super(p);
        this.me = p;
        this.maxDepth = Math.max(1, maxDepth);
    }

    // ===================== COUP À JOUER =====================

    @Override
    public AbstractPly giveYourMove(IBoard board) {

        if (board == null || board.isGameOver()) return null;

        List<AbstractPly> moves = listMoves(board);
        if (moves.isEmpty()) return null;

        boolean isMax = board.getCurrentPlayer() == me;

        int bestValue = isMax ? Integer.MIN_VALUE : Integer.MAX_VALUE;
        List<AbstractPly> bestMoves = new ArrayList<>();

        int alpha = Integer.MIN_VALUE;
        int beta = Integer.MAX_VALUE;

        for (AbstractPly m : moves) {
            IBoard next = board.safeCopy();
            next.doPly(m);

            int value = alphaBeta(next, maxDepth - 1, alpha, beta);

            if (isMax) {
                if (value > bestValue) {
                    bestValue = value;
                    bestMoves.clear();
                    bestMoves.add(m);
                } else if (value == bestValue) {
                    bestMoves.add(m);
                }
                alpha = Math.max(alpha, bestValue);
            } else {
                if (value < bestValue) {
                    bestValue = value;
                    bestMoves.clear();
                    bestMoves.add(m);
                } else if (value == bestValue) {
                    bestMoves.add(m);
                }
                beta = Math.min(beta, bestValue);
            }
        }

        return bestMoves.get(rng.nextInt(bestMoves.size()));
    }

    // ===================== ALPHA-BETA =====================

    private int alphaBeta(IBoard board, int depth, int alpha, int beta) {

        if (board.isGameOver()) {
            return terminalValue(board);
        }

        if (depth == 0) {
            return evaluate(board);
        }

        List<AbstractPly> moves = listMoves(board);
        if (moves.isEmpty()) {
            return evaluate(board);
        }

        boolean isMax = board.getCurrentPlayer() == me;

        if (isMax) {
            int best = Integer.MIN_VALUE;
            for (AbstractPly m : moves) {
                IBoard next = board.safeCopy();
                next.doPly(m);

                int val = alphaBeta(next, depth - 1, alpha, beta);
                best = Math.max(best, val);
                alpha = Math.max(alpha, best);

                if (alpha >= beta) break;
            }
            return best;
        } else {
            int best = Integer.MAX_VALUE;
            for (AbstractPly m : moves) {
                IBoard next = board.safeCopy();
                next.doPly(m);

                int val = alphaBeta(next, depth - 1, alpha, beta);
                best = Math.min(best, val);
                beta = Math.min(beta, best);

                if (alpha >= beta) break;
            }
            return best;
        }
    }

    // ===================== TERMINAL =====================

    private int terminalValue(IBoard board) {
        Result r = board.getResult();
        if (r == null) return 0;

        boolean botIsP1 = (me == Player.PLAYER1);

        if (r == Result.DRAW) return 0;

        if (botIsP1) {
            return (r == Result.WIN) ? 100000 : -100000;
        } else {
            return (r == Result.LOSS) ? 100000 : -100000;
        }
    }

    // ===================== ÉVALUATEUR =====================

    /**
     * Évaluateur heuristique Avalam :
     * - tours finales > quasi finales > stables > faibles
     * - approximation du score final
     */
    private int evaluate(IBoard board) {

        if (!(board instanceof AvalamBoard)) return 0;
        AvalamBoard b = (AvalamBoard) board;

        Color myColor = (me == Player.PLAYER1) ? Color.YELLOW : Color.RED;
        Color oppColor = (me == Player.PLAYER1) ? Color.RED : Color.YELLOW;

        int score = 0;

        for (int r = 0; r < AvalamBoard.SIZE; r++) {
            for (int c = 0; c < AvalamBoard.SIZE; c++) {

                Tower t = b.getTowerAt(r, c);
                if (t == null) continue;

                int h = t.getHeight();
                int value;

                if (h == 5) value = 1000;      // tour gagnée
                else if (h == 4) value = 300;  // quasi gagnée
                else if (h == 3) value = 120;  // stable
                else if (h == 2) value = 40;
                else value = 10;

                if (t.getColor() == myColor) score += value;
                else if (t.getColor() == oppColor) score -= value;
            }
        }

        return score;
    }

    // ===================== OUTILS =====================

    private List<AbstractPly> listMoves(IBoard board) {
        List<AbstractPly> moves = new ArrayList<>();
        Iterator<AbstractPly> it = board.iterator();
        while (it.hasNext()) moves.add(it.next());
        return moves;
    }
}