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

import 'package:flutter/material.dart';

class TimelineGeometry {
  const TimelineGeometry({
    required this.visibleStart,
    required this.visibleEnd,
    required this.pixelsPerMinute,
    this.minCardHeight = 72,
  });

  final TimeOfDay visibleStart;
  final TimeOfDay visibleEnd;
  final double pixelsPerMinute;
  final double minCardHeight;

  int get startMinutes => visibleStart.hour * 60 + visibleStart.minute;

  int get endMinutes => visibleEnd.hour * 60 + visibleEnd.minute;

  double get totalHeight => (endMinutes - startMinutes) * pixelsPerMinute;

  double yForMinutesSinceMidnight(int minutes) {
    return (minutes - startMinutes) * pixelsPerMinute;
  }

  double heightForDuration(int minutes) {
    final height = minutes * pixelsPerMinute;
    return height < minCardHeight ? minCardHeight : height;
  }

  List<TimelineTick> ticks({int stepMinutes = 15}) {
    return [
      for (
        var minute = startMinutes;
        minute <= endMinutes;
        minute += stepMinutes
      )
        TimelineTick(
          minutesSinceMidnight: minute,
          y: yForMinutesSinceMidnight(minute),
          label: _labelFor(minute),
          major: minute % 60 == 0,
        ),
    ];
  }

  static String _labelFor(int minutes) {
    final hour24 = minutes ~/ 60;
    final minute = minutes % 60;
    final period = hour24 >= 12 ? 'PM' : 'AM';
    final rawHour = hour24 % 12;
    final hour = rawHour == 0 ? 12 : rawHour;
    if (minute == 0) {
      return '$hour:00 $period';
    }
    return '$hour:${minute.toString().padLeft(2, '0')}';
  }
}

class TimelineTick {
  const TimelineTick({
    required this.minutesSinceMidnight,
    required this.y,
    required this.label,
    required this.major,
  });

  final int minutesSinceMidnight;
  final double y;
  final String label;
  final bool major;
}