import 'dart:math';
import 'package:flutter/material.dart';

/// Puzzle en pièces éparpillées, déplacées par glisser-déposer avec
/// accrochage ("snap") à la bonne position. Équivalent de `PuzzleGame.tsx`
/// (web) — la variante non-sliding (`isSlidingPuzzle == false`).
class GuidedPathPuzzle extends StatefulWidget {
  final String imageUrl;
  final int rows;
  final int cols;
  final Color accentColor;
  final bool isGame;
  final VoidCallback onSolved;

  const GuidedPathPuzzle({
    Key? key,
    required this.imageUrl,
    required this.rows,
    required this.cols,
    required this.accentColor,
    required this.isGame,
    required this.onSolved,
  }) : super(key: key);

  @override
  State<GuidedPathPuzzle> createState() => _GuidedPathPuzzleState();
}

class _Piece {
  final int row;
  final int col;
  Offset pos; // position courante (px depuis le coin haut-gauche du board)
  bool placed = false;
  double z;

  _Piece({required this.row, required this.col, required this.pos, this.z = 0});

  int get id => row * 1000 + col;
}

class _GuidedPathPuzzleState extends State<GuidedPathPuzzle> {
  List<_Piece> _pieces = [];
  bool _showHint = false;
  bool _solved = false;
  double _topZ = 1;
  int? _draggingId;

  @override
  void initState() {
    super.initState();
  }

  void _initPieces(double board) {
    if (_pieces.isNotEmpty) return;
    final pw = board / widget.cols;
    final ph = board / widget.rows;
    final rand = Random();
    final list = <_Piece>[];
    var z = 1.0;
    for (int r = 0; r < widget.rows; r++) {
      for (int c = 0; c < widget.cols; c++) {
        list.add(_Piece(
          row: r,
          col: c,
          pos: Offset(rand.nextDouble() * (board - pw), rand.nextDouble() * (board - ph)),
          z: z++,
        ));
      }
    }
    _pieces = list;
    _topZ = z;
  }

  void _onPanStart(_Piece piece) {
    if (piece.placed || _solved) return;
    setState(() {
      _draggingId = piece.id;
      piece.z = _topZ++;
    });
  }

  void _onPanUpdate(_Piece piece, DragUpdateDetails details, double board) {
    if (piece.placed || _solved) return;
    setState(() {
      final pw = board / widget.cols;
      final ph = board / widget.rows;
      piece.pos = Offset(
        (piece.pos.dx + details.delta.dx).clamp(0.0, board - pw),
        (piece.pos.dy + details.delta.dy).clamp(0.0, board - ph),
      );
    });
  }

  void _onPanEnd(_Piece piece, double board) {
    if (piece.placed || _solved) return;
    final pw = board / widget.cols;
    final ph = board / widget.rows;
    final targetX = piece.col * pw;
    final targetY = piece.row * ph;
    final dx = piece.pos.dx - targetX;
    final dy = piece.pos.dy - targetY;
    final threshold = min(pw, ph) * 0.35;

    setState(() {
      _draggingId = null;
      if (dx.abs() < threshold && dy.abs() < threshold) {
        piece.pos = Offset(targetX, targetY);
        piece.placed = true;
        piece.z = 0;
      }
      if (_pieces.every((p) => p.placed)) {
        _solved = true;
        Future.delayed(const Duration(milliseconds: 400), () {
          if (mounted) widget.onSolved();
        });
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return LayoutBuilder(
      builder: (context, constraints) {
        final board = constraints.maxWidth.isFinite
            ? constraints.maxWidth
            : MediaQuery.of(context).size.width - 64;
        _initPieces(board);
        final pw = board / widget.cols;
        final ph = board / widget.rows;
        final sorted = [..._pieces]..sort((a, b) => a.z.compareTo(b.z));

        return SizedBox(
          width: board,
          height: board,
          child: Stack(
            clipBehavior: Clip.none,
            children: [
              // Cadre du plateau (toujours visible)
              Container(
                decoration: BoxDecoration(
                  borderRadius: BorderRadius.circular(8),
                  border: Border.all(color: Colors.black.withOpacity(0.18), width: 1.5),
                  color: Colors.white.withOpacity(0.4),
                ),
              ),
              if (_showHint && !_solved)
                Positioned.fill(
                  child: Opacity(
                    opacity: 0.55,
                    child: Image.network(widget.imageUrl, fit: BoxFit.cover),
                  ),
                ),
              for (final piece in sorted)
                Positioned(
                  left: piece.pos.dx,
                  top: piece.pos.dy,
                  width: pw,
                  height: ph,
                  child: GestureDetector(
                    onPanStart: (_) => _onPanStart(piece),
                    onPanUpdate: (d) => _onPanUpdate(piece, d, board),
                    onPanEnd: (_) => _onPanEnd(piece, board),
                    child: Container(
                      margin: const EdgeInsets.all(1),
                      decoration: BoxDecoration(
                        borderRadius: BorderRadius.circular(6),
                        border: Border.all(color: Colors.black.withOpacity(0.15)),
                        boxShadow: piece.placed
                            ? []
                            : [
                                BoxShadow(
                                  color: Colors.black.withOpacity(
                                      _draggingId == piece.id ? 0.35 : 0.2),
                                  blurRadius: _draggingId == piece.id ? 12 : 6,
                                ),
                              ],
                      ),
                      transform: _draggingId == piece.id
                          ? (Matrix4.identity()..scaleByDouble(1.06, 1.06, 1.06, 1.0))
                          : Matrix4.identity(),
                      child: ClipRRect(
                        borderRadius: BorderRadius.circular(6),
                        child: OverflowBox(
                          maxWidth: board,
                          maxHeight: board,
                          alignment: Alignment(
                            widget.cols == 1 ? 0.0 : -1.0 + (piece.col * 2 / (widget.cols - 1)),
                            widget.rows == 1 ? 0.0 : -1.0 + (piece.row * 2 / (widget.rows - 1)),
                          ),
                          child: SizedBox(
                            width: board,
                            height: board,
                            child: Image.network(widget.imageUrl, fit: BoxFit.cover),
                          ),
                        ),
                      ),
                    ),
                  ),
                ),
              if (_solved)
                Positioned.fill(
                  child: Container(
                    decoration: BoxDecoration(
                      color: Colors.black.withOpacity(0.35),
                      borderRadius: BorderRadius.circular(8),
                    ),
                    alignment: Alignment.center,
                    child: const Text(
                      'Puzzle résolu !',
                      style: TextStyle(color: Colors.white, fontSize: 15, fontWeight: FontWeight.w600),
                    ),
                  ),
                ),
              if (!_solved)
                Positioned(
                  right: 8,
                  bottom: 8,
                  child: GestureDetector(
                    onTap: () => setState(() => _showHint = !_showHint),
                    child: Container(
                      width: 36,
                      height: 36,
                      decoration: BoxDecoration(
                        shape: BoxShape.circle,
                        color: _showHint
                            ? widget.accentColor
                            : (widget.isGame ? Colors.white.withOpacity(0.1) : Colors.white),
                        boxShadow: [BoxShadow(color: Colors.black.withOpacity(0.2), blurRadius: 8)],
                      ),
                      child: Icon(
                        Icons.remove_red_eye,
                        size: 18,
                        color: _showHint
                            ? (widget.isGame ? const Color(0xFF1a1305) : Colors.white)
                            : (widget.isGame ? const Color(0xFFD4AF37) : const Color(0xFF54636E)),
                      ),
                    ),
                  ),
                ),
            ],
          ),
        );
      },
    );
  }
}