/// Renders Timeline Axis pieces for the FocusFlow Flutter timeline.
library;

import 'package:flutter/material.dart';

import '../../theme/focus_flow_tokens.dart';
import 'timeline_geometry.dart';

/// Time labels and rail shown beside the compact timeline.
class TimelineAxis extends StatelessWidget {
  /// Creates a timeline axis for [geometry].
  const TimelineAxis({required this.geometry, super.key});

  /// Geometry used to position labels and tick marks.
  final TimelineGeometry geometry;

  @override
  Widget build(BuildContext context) {
    final ticks = geometry.ticks();
    return SizedBox(
      width: FocusFlowTokens.timelineRailWidth,
      height: geometry.totalHeight + 24,
      child: Stack(
        children: [
          Positioned(
            left: 92,
            top: 0,
            bottom: 0,
            child: Container(width: 2, color: FocusFlowTokens.rail),
          ),
          for (final tick in ticks)
            Positioned(
              top: tick.y - 10,
              left: 0,
              width: 86,
              child: Text(
                tick.label,
                textAlign: TextAlign.right,
                style: TextStyle(
                  color: tick.major
                      ? FocusFlowTokens.textPrimary
                      : FocusFlowTokens.textFaint,
                  fontSize: tick.major ? 16 : 14,
                  fontWeight: tick.major ? FontWeight.w600 : FontWeight.w400,
                ),
              ),
            ),
          for (final tick in ticks.where((tick) => tick.major))
            Positioned(
              top: tick.y - 6,
              left: 87,
              child: const DecoratedBox(
                decoration: BoxDecoration(
                  color: FocusFlowTokens.rail,
                  shape: BoxShape.circle,
                ),
                child: SizedBox(width: 12, height: 12),
              ),
            ),
        ],
      ),
    );
  }
}

/// Background grid aligned to timeline tick marks.
class TimelineGrid extends StatelessWidget {
  /// Creates a timeline grid for [geometry].
  const TimelineGrid({required this.geometry, super.key});

  /// Geometry used to position grid lines.
  final TimelineGeometry geometry;

  @override
  Widget build(BuildContext context) {
    return CustomPaint(
      painter: _TimelineGridPainter(geometry),
      size: Size.infinite,
    );
  }
}

class _TimelineGridPainter extends CustomPainter {
  const _TimelineGridPainter(this.geometry);

  final TimelineGeometry geometry;

  @override
  void paint(Canvas canvas, Size size) {
    final paint = Paint()
      ..color = FocusFlowTokens.gridLine
      ..strokeWidth = 1;
    for (final tick in geometry.ticks()) {
      canvas.drawLine(
        Offset(0, tick.y),
        Offset(size.width, tick.y),
        paint
          ..color = tick.major
              ? FocusFlowTokens.gridLine.withValues(alpha: 0.72)
              : FocusFlowTokens.gridLine,
      );
    }
  }

  @override
  bool shouldRepaint(covariant _TimelineGridPainter oldDelegate) {
    return oldDelegate.geometry != geometry;
  }
}