import "package:flutter/material.dart";

class TripDiagramEntry {
  const TripDiagramEntry({required this.label, this.labelIcon, this.subtitle, this.time});

  final String label;
  final IconData? labelIcon;
  final String? subtitle;
  final String? time;
}

class TripDiagram extends StatelessWidget {
  const TripDiagram({
    required this.entries,
    super.key,
    this.leftOffset = 0,
    this.rowHeight = 32,
    this.lineWidth = 7,
    this.lineColor,
    this.highlightLastEntry = false,
    this.labelOffset = 26,
    this.rightPadding = 16,
    this.oddRowColor,
    this.terminalRowColor,
    this.stationTextStyle,
    this.timeTextStyle,
    this.missingTimeTextStyle,
    this.emptyMessage = "No stations found.",
    this.emptyTextStyle,
  });

  final List<TripDiagramEntry> entries;
  final double leftOffset;
  final double rowHeight;
  final double lineWidth;
  final Color? lineColor;
  final bool highlightLastEntry;
  final double labelOffset;
  final double rightPadding;
  final Color? oddRowColor;
  final Color? terminalRowColor;
  final TextStyle? stationTextStyle;
  final TextStyle? timeTextStyle;
  final TextStyle? missingTimeTextStyle;
  final String emptyMessage;
  final TextStyle? emptyTextStyle;

  @override
  Widget build(BuildContext context) {
    final resolvedLineColor = lineColor ?? Theme.of(context).colorScheme.primary;

    final deduped = entries;

    if (deduped.isEmpty) {
      return Text(
        emptyMessage,
        style:
            emptyTextStyle ??
            TextStyle(color: Theme.of(context).colorScheme.onSurfaceVariant),
      );
    }

    final totalHeight = deduped.length * rowHeight;

    return Stack(
      children: [
        SizedBox(
          height: totalHeight,
          width: double.infinity,
          child: CustomPaint(
            painter: _TripDiagramPainter(
              count: deduped.length,
              rowHeight: rowHeight,
              lineWidth: lineWidth,
              lineColor: resolvedLineColor,
              leftOffset: leftOffset,
            ),
          ),
        ),
        Positioned.fill(
          child: Column(
            children: List.generate(deduped.length, (index) {
              final entry = deduped[index];
              final time = entry.time;
              final isTerminalRow = highlightLastEntry && index == deduped.length - 1;

              return Container(
                height: rowHeight,
                color: isTerminalRow
                    ? (terminalRowColor ?? resolvedLineColor.withValues(alpha: 0.12))
                    : index.isOdd
                    ? (oddRowColor ?? Colors.white.withValues(alpha: 0.03))
                    : null,
                child: Padding(
                  padding: EdgeInsets.only(
                    left: leftOffset + labelOffset,
                    right: rightPadding,
                  ),
                  child: Row(
                    mainAxisAlignment: MainAxisAlignment.spaceBetween,
                    children: [
                      Expanded(
                        child: Column(
                          crossAxisAlignment: CrossAxisAlignment.start,
                          mainAxisAlignment: MainAxisAlignment.center,
                          children: [

                            Row(
                              children: [
                                Text(
                                  entry.label,
                                  style:
                                      stationTextStyle ??
                                      const TextStyle(
                                        fontSize: 15,
                                        color: Color(0xFFDDDDDD),
                                        fontWeight: FontWeight.w600,
                                        letterSpacing: 0.5,
                                      ),
                                  overflow: TextOverflow.ellipsis,
                                ),

                                if (entry.labelIcon != null) ...[
                                  const SizedBox(width: 4),
                                  Icon(
                                    entry.labelIcon,
                                    size: 12,
                                    color: const Color(0xFFBBBBBB),
                                  ),
                                ]
                              ],
                            ),
                            if (entry.subtitle != null)
                              Text(
                              entry.subtitle!,
                              style:
                              stationTextStyle ??
                                  const TextStyle(
                                    fontSize: 11,
                                    color: Color(0xFFDDDDDD),
                                    fontWeight: FontWeight.w600,
                                    letterSpacing: 0.5,
                                  ),
                              overflow: TextOverflow.ellipsis,
                            ),
                          ],
                        ),
                      ),
                      const SizedBox(width: 12),
                      Text(
                        time ?? "--:--",
                        style: time != null
                            ? (timeTextStyle ??
                                const TextStyle(
                                  fontSize: 15,
                                  fontFamily: "monospace",
                                  fontWeight: FontWeight.w700,
                                  color: Color(0xFFEEEEEE),
                                ))
                            : (missingTimeTextStyle ??
                                const TextStyle(
                                  fontSize: 15,
                                  fontFamily: "monospace",
                                  fontWeight: FontWeight.w700,
                                  color: Color(0xFF555555),
                                )),
                      ),
                    ],
                  ),
                ),
              );
            }),
          ),
        ),
      ],
    );
  }
}

class _TripDiagramPainter extends CustomPainter {
  const _TripDiagramPainter({
    required this.count,
    required this.rowHeight,
    required this.lineWidth,
    required this.lineColor,
    this.leftOffset = 0,
  });

  final int count;
  final double rowHeight;
  final double lineWidth;
  final Color lineColor;
  final double leftOffset;

  static const double _linePad = 4.0;
  static const double _blobPad = 4.0;
  static const double _centerSize = 4.0;
  static const double _cornerFactor = 0.3;

  @override
  void paint(Canvas canvas, Size size) {
    if (count <= 0) return;

    final strokeWidth = lineWidth / 2.0;
    final ringSize = _centerSize + strokeWidth;
    final paddingWidth = strokeWidth + _blobPad;
    final centerX = leftOffset + ringSize / 2 + paddingWidth / 2 + 2;
    final firstY = rowHeight / 2;
    final lastY = (count - 1) * rowHeight + rowHeight / 2;

    final nodeRects = List.generate(count, (index) {
      final centerY = index * rowHeight + rowHeight / 2;
      final rect = Rect.fromCenter(
        center: Offset(centerX, centerY),
        width: ringSize,
        height: ringSize,
      );
      return RRect.fromRectAndRadius(
        rect,
        Radius.circular(ringSize * _cornerFactor),
      );
    });

    for (final rect in nodeRects) {
      canvas.drawRRect(
        rect,
        Paint()
          ..color = Colors.white
          ..strokeWidth = paddingWidth
          ..style = PaintingStyle.stroke,
      );
    }

    canvas.drawLine(
      Offset(centerX, firstY),
      Offset(centerX, lastY),
      Paint()
        ..color = Colors.white
        ..strokeWidth = lineWidth + _linePad
        ..strokeCap = StrokeCap.round
        ..style = PaintingStyle.stroke,
    );

    canvas.drawLine(
      Offset(centerX, firstY),
      Offset(centerX, lastY),
      Paint()
        ..color = lineColor
        ..strokeWidth = lineWidth
        ..strokeCap = StrokeCap.round
        ..style = PaintingStyle.stroke,
    );

    for (final rect in nodeRects) {
      final centerRect = rect.deflate(strokeWidth / 2);
      canvas.drawRRect(
        centerRect,
        Paint()
          ..color = Colors.white
          ..style = PaintingStyle.fill,
      );
      canvas.drawRRect(
        rect,
        Paint()
          ..color = lineColor
          ..strokeWidth = strokeWidth
          ..style = PaintingStyle.stroke,
      );
    }
  }

  @override
  bool shouldRepaint(covariant _TripDiagramPainter oldDelegate) {
    return oldDelegate.count != count ||
        oldDelegate.rowHeight != rowHeight ||
        oldDelegate.lineWidth != lineWidth ||
        oldDelegate.lineColor != lineColor ||
        oldDelegate.leftOffset != leftOffset;
  }
}