<?php

namespace com\nlf\calendar;

use com\nlf\calendar\util\SolarUtil;
use DateTime;

bcscale(12);

/**
 * 阳历周
 * @package com\nlf\calendar
 */
class SolarWeek
{

 /**
 * 年
 * @var int
 */
 private $year;

 /**
 * 月
 * @var int
 */
 private $month;

 /**
 * 日
 * @var int
 */
 private $day;

 /**
 * 星期几作为一周的开始,1234560分别代表星期一至星期天
 * @var int
 */
 private $start;

 function __construct($year, $month, $day, $start)
 {
 $this->year = intval($year);
 $this->month = intval($month);
 $this->day = intval($day);
 $this->start = intval($start);
 }

 public function toString()
 {
 return $this->year . '.' . $this->month . '.' . $this->getIndex();
 }

 public function __toString()
 {
 return $this->toString();
 }

 public function toFullString()
 {
 return $this->year . '年' . $this->month . '月第' . $this->getIndex() . '周';
 }

 /**
 * 通过指定年月日获取阳历周
 * @param int $year 年
 * @param int $month 月,1到12
 * @param int $day 日,1到31
 * @param int $start 星期几作为一周的开始,1234560分别代表星期一至星期天
 * @return SolarWeek
 */
 public static function fromYmd($year, $month, $day, $start)
 {
 return new SolarWeek($year, $month, $day, $start);
 }

 /**
 * 通过指定DateTime获取阳历周
 * @param DateTime $date DateTime
 * @param int $start 星期几作为一周的开始,1234560分别代表星期一至星期天
 * @return SolarWeek
 */
 public static function fromDate($date, $start)
 {
 $solar = Solar::fromDate($date);
 return new SolarWeek($solar->getYear(), $solar->getMonth(), $solar->getDay(), $start);
 }

 public function getYear()
 {
 return $this->year;
 }

 public function getMonth()
 {
 return $this->month;
 }

 public function getDay()
 {
 return $this->day;
 }

 public function getStart()
 {
 return $this->start;
 }

 /**
 * 获取当前日期是在当月第几周
 * @return int
 */
 public function getIndex()
 {
 $offset = Solar::fromYmd($this->year, $this->month, 1)->getWeek() - $this->start;
 if ($offset < 0) {
 $offset += 7;
 }
 return (int)ceil(($this->day + $offset) / 7);
 }

 /**
 * 获取当前日期是在当年第几周
 * @return int
 */
 public function getIndexInYear()
 {
 $offset = Solar::fromYmd($this->year, 1, 1)->getWeek() - $this->start;
 if ($offset < 0) {
 $offset += 7;
 }
 return (int)ceil((SolarUtil::getDaysInYear($this->year, $this->month, $this->day) + $offset) / 7);
 }

 /**
 * 周推移
 * @param int $weeks 推移的周数,负数为倒推
 * @param bool $separateMonth 是否按月单独计算
 * @return SolarWeek
 */
 public function next($weeks, $separateMonth)
 {
 if (0 === $weeks) {
 return SolarWeek::fromYmd($this->year, $this->month, $this->day, $this->start);
 }
 $solar = Solar::fromYmd($this->year, $this->month, $this->day);
 if ($separateMonth) {
 $n = $weeks;
 $week = SolarWeek::fromYmd($solar->getYear(), $solar->getMonth(), $solar->getDay(), $this->start);
 $month = $this->month;
 $plus = $n > 0;
 while (0 !== $n) {
 $solar = $solar->next($plus ? 7 : -7);
 $week = SolarWeek::fromYmd($solar->getYear(), $solar->getMonth(), $solar->getDay(), $this->start);
 $weekMonth = $week->getMonth();
 if ($month !== $weekMonth) {
 $index = $week->getIndex();
 if ($plus) {
 if (1 === $index) {
 $firstDay = $week->getFirstDay();
 $week = SolarWeek::fromYmd($firstDay->getYear(), $firstDay->getMonth(), $firstDay->getDay(), $this->start);
 $weekMonth = $week->getMonth();
 } else {
 $solar = Solar::fromYmd($week->getYear(), $week->getMonth(), 1);
 $week = SolarWeek::fromYmd($solar->getYear(), $solar->getMonth(), $solar->getDay(), $this->start);
 }
 } else {
 if (SolarUtil::getWeeksOfMonth($week->getYear(), $week->getMonth(), $week->getStart()) === $index) {
 $lastDay = $week->getFirstDay()->next(6);
 $week = SolarWeek::fromYmd($lastDay->getYear(), $lastDay->getMonth(), $lastDay->getDay(), $this->start);
 $weekMonth = $week->getMonth();
 } else {
 $solar = Solar::fromYmd($week->year, $week->month, SolarUtil::getDaysOfMonth($week->getYear(), $week->getMonth()));
 $week = SolarWeek::fromYmd($solar->getYear(), $solar->getMonth(), $solar->getDay(), $this->start);
 }
 }
 $month = $weekMonth;
 }
 $n -= $plus ? 1 : -1;
 }
 return $week;
 } else {
 $solar = $solar->next($weeks * 7);
 return SolarWeek::fromYmd($solar->getYear(), $solar->getMonth(), $solar->getDay(), $this->start);
 }
 }

 /**
 * 获取本周第一天的阳历日期(可能跨月)
 * @return Solar
 */
 public function getFirstDay()
 {
 $solar = Solar::fromYmd($this->year, $this->month, $this->day);
 $prev = $solar->getWeek() - $this->start;
 if ($prev < 0) {
 $prev += 7;
 }
 return $solar->next(-$prev);
 }

 /**
 * 获取本周第一天的阳历日期(仅限当月)
 * @return Solar
 */
 public function getFirstDayInMonth()
 {
 $days = $this->getDays();
 foreach ($days as $day) {
 if ($this->month === $day->getMonth()) {
 return $day;
 }
 }
 return null;
 }

 /**
 * 获取本周的阳历日期列表(可能跨月)
 * @return Solar[]
 */
 public function getDays()
 {
 $firstDay = $this->getFirstDay();
 $l = array();
 if (null == $firstDay) {
 return $l;
 }
 $l[] = $firstDay;
 for ($i = 1; $i < 7; $i++) {
 $l[] = $firstDay->next($i);
 }
 return $l;
 }

 /**
 * 获取本周的阳历日期列表(仅限当月)
 * @return Solar[]
 */
 public function getDaysInMonth()
 {
 $days = $this->getDays();
 $l = array();
 foreach ($days as $day) {
 if ($this->month !== $day->getMonth()) {
 continue;
 }
 $l[] = $day;
 }
 return $l;
 }

}