PhutilLunarPhase.php
d72b0f90af7dstable

PhutilLunarPhase.php
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			<?php

			/**
			* Compute the phase of the terran moon for a given epoch.
			*
			* $moon = new PhutilLunarPhase(time());
			* $moon->isFull();
			*/
			final class PhutilLunarPhase {

			private $epoch;

			public function __construct($epoch) {
			$this->epoch = $epoch;
			}

			private function getPhase() {
			// (Aug 11, 1999) A new moon.
			$new_moon_epoch = 934354800;

			// Number of seconds in the lunar phase.
			$phase_length = 2551442.8768992;

			return fmod($this->epoch - $new_moon_epoch, $phase_length) / $phase_length;
			}

			public function isFull() {
			return abs($this->getPhase() - 0.5) < 0.02;
			}

			public function isNew() {
			return $this->getPhase() < 0.02 \|\| $this->getPhase() > 0.98;
			}

			public function isWaxing() {
			return $this->getPhase() < 0.5;
			}

			public function isWaning() {
			return $this->getPhase() > 0.5;
			}

			}