import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import '../../../../core/theme/app_theme.dart';
import '../../models/technical_analysis_model.dart';
import 'candlestick_painter.dart';

export '../../models/technical_analysis_model.dart' show CandleModel, IndicatorModel, ChartPatternModel, PatternPoint, StrategySignalModel;

class CandlestickChart extends StatefulWidget {
  final List<CandleModel> candles;
  final List<ChartPatternModel> patterns;
  final List<StrategySignalModel> signals;
  final List<IndicatorModel> indicators;
  final bool showSma50;
  final bool showSma200;
  final bool showEma;
  final bool showPatterns;
  final bool showSignals;
  final bool showSupertrend;
  final double height;
  final bool isFullscreen;
  final VoidCallback? onToggleFullscreen;

  const CandlestickChart({
    super.key,
    required this.candles,
    this.patterns = const [],
    this.signals = const [],
    this.indicators = const [],
    this.showSma50 = true,
    this.showSma200 = true,
    this.showEma = true,
    this.showPatterns = true,
    this.showSignals = true,
    this.showSupertrend = true,
    this.height = 420,
    this.isFullscreen = false,
    this.onToggleFullscreen,
  });

  @override
  State<CandlestickChart> createState() => _CandlestickChartState();
}

class _CandlestickChartState extends State<CandlestickChart> {
  double _scale = 1.0;
  double _panOffset = 0.0;
  double _baseScale = 1.0;
  double _basePanOffset = 0.0;
  Offset _startFocalPoint = Offset.zero;
  bool _isDragging = false;
  Offset? _tapPosition;
  CandleModel? _selectedCandle;

  @override
  void initState() {
    super.initState();
    WidgetsBinding.instance.addPostFrameCallback((_) {
      _fitLatestCandles();
    });
  }

  @override
  void didUpdateWidget(covariant CandlestickChart oldWidget) {
    super.didUpdateWidget(oldWidget);
    if (oldWidget.candles.length != widget.candles.length) {
      WidgetsBinding.instance.addPostFrameCallback((_) {
        _fitLatestCandles();
      });
    }
  }

  void _fitLatestCandles() {
    if (widget.candles.isEmpty || !mounted) return;
    final renderBox = context.findRenderObject() as RenderBox?;
    final width = (renderBox?.size.width ?? 600) - 60;
    final double candleWidth = 10.0 * _scale;
    final double totalCandleSpace = candleWidth + (5.0 * _scale);
    final double futureSpace = totalCandleSpace * 10;
    final double totalWidth = (widget.candles.length * totalCandleSpace) + futureSpace;
    
    setState(() {
      if (totalWidth > width) {
        _panOffset = width - totalWidth;
      } else {
        _panOffset = 0.0;
      }
    });
  }

  void _applyZoom(double factor, [double? focalX]) {
    if (widget.candles.isEmpty || !mounted) return;
    final renderBox = context.findRenderObject() as RenderBox?;
    final chartWidth = (renderBox?.size.width ?? 600) - 60;
    final fx = focalX ?? (chartWidth / 2);

    setState(() {
      final oldScale = _scale;
      _scale = (_scale * factor).clamp(0.1, 6.0);
      _panOffset = fx - ((fx - _panOffset) * (_scale / oldScale));
      _clampPanOffset(chartWidth);
    });
  }

  void _clampPanOffset(double chartWidth) {
    if (widget.candles.isEmpty) return;
    final double totalCandleSpace = (10.0 + 5.0) * _scale;
    final double totalWidth = (widget.candles.length * totalCandleSpace) + (totalCandleSpace * 10);

    if (totalWidth <= chartWidth) {
      _panOffset = 0.0;
    } else {
      final double minPan = chartWidth - totalWidth - 30;
      const double maxPan = 30.0;
      _panOffset = _panOffset.clamp(minPan, maxPan);
    }
  }

  @override
  Widget build(BuildContext context) {
    final theme = AppTheme.activePreset;

    return Container(
      height: widget.height,
      decoration: BoxDecoration(
        color: theme.cardSurface,
        borderRadius: BorderRadius.circular(16),
        border: Border.all(color: theme.glassBorder),
      ),
      child: ClipRRect(
        borderRadius: BorderRadius.circular(16),
        child: Listener(
          onPointerSignal: (pointerSignal) {
            if (pointerSignal is PointerScrollEvent) {
              if (pointerSignal.scrollDelta.dx != 0) {
                final renderBox = context.findRenderObject() as RenderBox?;
                final chartWidth = (renderBox?.size.width ?? 600) - 60;
                setState(() {
                  _panOffset -= pointerSignal.scrollDelta.dx;
                  _clampPanOffset(chartWidth);
                });
              } else if (pointerSignal.scrollDelta.dy != 0) {
                final zoomFactor = pointerSignal.scrollDelta.dy < 0 ? 1.15 : 0.85;
                _applyZoom(zoomFactor, pointerSignal.localPosition.dx);
              }
            }
          },
          child: MouseRegion(
            cursor: _isDragging ? SystemMouseCursors.grabbing : SystemMouseCursors.grab,
            child: GestureDetector(
              behavior: HitTestBehavior.opaque,
              onScaleStart: (details) {
                _baseScale = _scale;
                _basePanOffset = _panOffset;
                _startFocalPoint = details.focalPoint;
                setState(() => _isDragging = true);
              },
              onScaleUpdate: (details) {
                final renderBox = context.findRenderObject() as RenderBox?;
                final chartWidth = (renderBox?.size.width ?? 600) - 60;
                setState(() {
                  if (details.scale != 1.0) {
                    final oldScale = _scale;
                    _scale = (_baseScale * details.scale).clamp(0.1, 6.0);
                    final fx = details.localFocalPoint.dx;
                    _panOffset = fx - ((fx - _basePanOffset) * (_scale / oldScale));
                  } else {
                    _panOffset = _basePanOffset + (details.focalPoint.dx - _startFocalPoint.dx);
                  }
                  _clampPanOffset(chartWidth);
                });
              },
              onScaleEnd: (details) {
                setState(() => _isDragging = false);
              },
              onTapDown: (details) {
                _handleTap(details.localPosition);
              },
              child: Stack(
                children: [
                  CustomPaint(
                    size: Size.infinite,
                    painter: CandlestickPainter(
                      candles: widget.candles,
                      patterns: widget.patterns,
                      signals: widget.signals,
                      indicators: widget.indicators,
                      scale: _scale,
                      panOffset: _panOffset,
                      theme: theme,
                      showPatterns: widget.showPatterns,
                      showSma50: widget.showSma50,
                      showSma200: widget.showSma200,
                      showEma: widget.showEma,
                      showSignals: widget.showSignals,
                      showSupertrend: widget.showSupertrend,
                      tapPosition: _tapPosition,
                    ),
                  ),
                  if (_selectedCandle != null) _buildTooltip(theme),
                  _buildZoomControls(theme),
                ],
              ),
            ),
          ),
        ),
      ),
    );
  }

  Widget _buildZoomControls(ThemePreset theme) {
    return Positioned(
      right: 10,
      bottom: 28,
      child: Container(
        decoration: BoxDecoration(
          color: theme.cardSurface.withValues(alpha: 0.9),
          borderRadius: BorderRadius.circular(8),
          border: Border.all(color: theme.glassBorder),
        ),
        padding: const EdgeInsets.symmetric(horizontal: 2, vertical: 2),
        child: Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            _buildZoomButton(icon: Icons.chevron_left, tooltip: 'Nach links bewegen', onTap: () {
              final renderBox = context.findRenderObject() as RenderBox?;
              setState(() { _panOffset += 150; _clampPanOffset((renderBox?.size.width ?? 600) - 60); });
            }),
            _buildZoomButton(icon: Icons.chevron_right, tooltip: 'Nach rechts bewegen', onTap: () {
              final renderBox = context.findRenderObject() as RenderBox?;
              setState(() { _panOffset -= 150; _clampPanOffset((renderBox?.size.width ?? 600) - 60); });
            }),
            Container(width: 1, height: 16, color: theme.glassBorder),
            _buildZoomButton(icon: Icons.add, tooltip: 'Vergrößern', onTap: () => _applyZoom(1.25)),
            _buildZoomButton(icon: Icons.remove, tooltip: 'Verkleinern', onTap: () => _applyZoom(0.8)),
            _buildZoomButton(icon: Icons.fit_screen_outlined, tooltip: 'Aktuelle Kerzen einpassen', onTap: _fitLatestCandles),
            _buildZoomButton(icon: Icons.refresh, tooltip: 'Zoom 1:1 zurücksetzen', onTap: () { setState(() => _scale = 1.0); _fitLatestCandles(); }),
            if (widget.onToggleFullscreen != null) ...[
              Container(width: 1, height: 16, color: theme.glassBorder),
              _buildZoomButton(
                icon: widget.isFullscreen ? Icons.fullscreen_exit : Icons.fullscreen,
                tooltip: widget.isFullscreen ? 'Vollbild beenden' : 'Vollbildmodus (Querformat)',
                onTap: widget.onToggleFullscreen!,
              ),
            ],
          ],
        ),
      ),
    );
  }

  Widget _buildZoomButton({required IconData icon, required String tooltip, required VoidCallback onTap}) {
    return Tooltip(
      message: tooltip,
      child: InkWell(
        onTap: onTap,
        borderRadius: BorderRadius.circular(6),
        child: Padding(
          padding: const EdgeInsets.all(6),
          child: Icon(icon, size: 16, color: Colors.white70),
        ),
      ),
    );
  }

  void _handleTap(Offset pos) {
    if (widget.candles.isEmpty) return;
    final double candleWidth = 10.0 * _scale;
    final double totalCandleSpace = candleWidth + (5.0 * _scale);
    final int index = ((pos.dx - _panOffset) / totalCandleSpace).round();

    if (index >= 0 && index < widget.candles.length) {
      setState(() {
        _tapPosition = pos;
        _selectedCandle = widget.candles[index];
      });
    }
  }

  Widget _buildTooltip(ThemePreset theme) {
    final c = _selectedCandle!;
    final dStr = "${c.timestamp.year}-${c.timestamp.month.toString().padLeft(2, '0')}-${c.timestamp.day.toString().padLeft(2, '0')}";

    return Positioned(
      left: 10,
      top: 10,
      child: Container(
        padding: const EdgeInsets.all(8),
        decoration: BoxDecoration(
          color: theme.cardSurface.withValues(alpha: 0.9),
          borderRadius: BorderRadius.circular(8),
          border: Border.all(color: theme.glassBorder),
        ),
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.start,
          mainAxisSize: MainAxisSize.min,
          children: [
            Text(dStr, style: TextStyle(color: theme.textMuted, fontSize: 12)),
            Text('O: ${c.open.toStringAsFixed(2)} | H: ${c.high.toStringAsFixed(2)} | L: ${c.low.toStringAsFixed(2)} | C: ${c.close.toStringAsFixed(2)}', style: TextStyle(color: theme.textPrimary, fontSize: 12)),
            Text('Vol: ${c.volume.toStringAsFixed(0)}', style: TextStyle(color: theme.textSecondary, fontSize: 11)),
          ],
        ),
      ),
    );
  }
}