tutorbookapp/tutorbook

import { Position } from 'lib/model/position';
import { Timeslot } from 'lib/model/timeslot';
import { getDate } from 'lib/utils/time';

export const WIDTH = 100;

export function getPosition(time: Date, width: number = WIDTH): Position {
  const minsFromMidnight = time.getHours() * 60 + time.getMinutes();
  return { x: time.getDay() * width, y: (minsFromMidnight / 15) * 12 };
}

export function getHeight(timeslot: Timeslot): number {
  const { from: start, to: end } = timeslot;
  const minsDuration = (end.valueOf() - start.valueOf()) / 60000;
  return (minsDuration / 15) * 12;
}

// Converts a given position and height into a `Timeslot`. Assumes each hour is
// 48px wide (12px = 15min) and each weekday is 82px wide (though those numbers
// can be configured).
export function getTimeslot(
  height: number,
  position: Position,
  original?: Timeslot,
  width: number = WIDTH,
  reference: Date = new Date(0)
): Timeslot {
  // Each column is 82px wide, so we merely divide to figure out which column
  // the `TimeslotRnd` is located (e.g. 0 = Sunday, 1 = Monday, etc).
  const weekday = Math.floor(position.x / width + 0.01);

  // This RND can represent timeslots not on 15min intervals (e.g. 8:37am to
  // 9:13am), but we snap back to 15min intervals when the RND is moved.
  const snappedPositionY = Math.round(position.y / 12);
  const snappedHeight = Math.round(height / 12);

  // The `TimeslotRnd` is set to snap every 12px which represents 15min
  // intervals. Midnight is shown at the top of the grid.
  const minsFromMidnight = snappedPositionY * 15;
  const minsDuration = snappedHeight * 15;

  const hours = Math.floor(minsFromMidnight / 60);
  const mins = minsFromMidnight % 60;
  const start = getDate(weekday, hours, mins, 0, 0, reference);
  const end = new Date(start.valueOf() + minsDuration * 60000);

  return new Timeslot({ ...original, from: start, to: end });
}