Different Variables with same value effecting change on the other - php

Question

Question:
Is there something weird about date-time that would affect the assignment of a variable?
The situation:
From Controller I'm passing a variable $startDate and on the view assigning it to different variables $day1, $day2, etc etc. I go through a loop on $day1 and I modify the day to increment $day1 by 1 using $day1->modify("+1 day")
$day2 the loop (in the else portion) doesn't trigger because the value of $startDate is too high. however, it's value should be the same as $day1 before modification.
the Code:
The controller
public function appointmentSearch()
{
$counselor = $this->session->userdata('idUser');
if($this->input->post('SearchAppointments'))
{
$fromDate = $_POST['fromDate'];
$fromTimeSlot = $this->Admin_model->TimeConversion($_POST['fromTime']);
$toDate = $_POST['toDate'];
$toTimeSlot = $this->Admin_model->TimeConversion($_POST['toTime']);
$theStart = new DateTime($fromDate);
$theEnd = new DateTime($toDate);
$difference = $theEnd->diff($theStart);
$dayCount = $difference->d;
$timeCount = (int)$toTimeSlot-(int)$fromTimeSlot;
$data['schedule'] = true;
$data['days'] = $dayCount;
$data['slots'] = $timeCount;
$data['dayStart'] = $theStart;
$data['dayEnd'] = $theEnd;
$data['slotStart'] = $fromTimeSlot;
$data['slotEnd'] = $toTimeSlot;
$data['r1Data'] = $this->Admin_model->GetOpenApptTimes($fromDate,$fromTimeSlot,$toDate,$toTimeSlot,1);
$data['r2Data'] = $this->Admin_model->GetOpenApptTimes($fromDate,$fromTimeSlot,$toDate,$toTimeSlot,2);
$data['r3Data'] = $this->Admin_model->GetOpenApptTimes($fromDate,$fromTimeSlot,$toDate,$toTimeSlot,3);
$data['r4Data'] = $this->Admin_model->GetOpenApptTimes($fromDate,$fromTimeSlot,$toDate,$toTimeSlot,4);
$data['r5Data'] = $this->Admin_model->GetOpenApptTimes($fromDate,$fromTimeSlot,$toDate,$toTimeSlot,5);
$data['r6Data'] = $this->Admin_model->GetOpenApptTimes($fromDate,$fromTimeSlot,$toDate,$toTimeSlot,6);
$data['r7Data'] = $this->Admin_model->GetOpenApptTimes($fromDate,$fromTimeSlot,$toDate,$toTimeSlot,7);
$data['r8Data'] = $this->Admin_model->GetOpenApptTimes($fromDate,$fromTimeSlot,$toDate,$toTimeSlot,8);
$data['r9Data'] = $this->Admin_model->GetOpenApptTimes($fromDate,$fromTimeSlot,$toDate,$toTimeSlot,9);
$data['r10Data'] = $this->Admin_model->GetOpenApptTimes($fromDate,$fromTimeSlot,$toDate,$toTimeSlot,10);
$this->load->view('admin/scheduler',$data);
}
}
The View:
<?php
if($schedule == true)
{ //if false we have search results
//classes for the form
$attributes = array('class' => 'row');
//normal attributtes for the time slots if they are blacked out
$subAttUnav = array('class' => 'btn btn-secondary btn-sm');
// if the used time slot is someone they can ask to move
$subAttMove = array('class' => 'btn btn-secondary btn-sm', 'style' => 'background:darkgrey;');
// it's wide open
$subAttOpen = array('class' => 'btn btn-secondary btn-sm');
if(count($r1Data) >= 1)
{ //room 1 has appoints scheduled during the time frame queried
echo '<div class="row" style="width:70%;margin:0 auto;"><h3 class="highlight">Room 1</h3>';
$day1 = $dayStart;
while($day1 <= $dayEnd)
{
$day1format = $day1->format('Y-m-d-H-i-s');
$dayArray = explode('-',$day1format);
for($i = 0;$i <= $slots; $i++)
{
$timeslot = $slotStart + $i;
$label = 'Book: ' . $timeslot . ':00 on ' . $dayArray[1] . '/' . $dayArray[2] . ' ';
foreach($r1Data as $index)
{
$row = explode('-',$index);
//var_dump($row);
$thisDay = $dayArray[0] . '/' . $dayArray[1] . '/' . $dayArray[2];
//echo '$thisDay =' . $thisDay . '</br>';
$apptDay = $row[6] . '/' . $row[7] . '/' . $row[8];
//echo '$apptDay =' . $apptDay . '</br>';
//echo '$timeslot =' . $timeslot . '</br>';
//echo '$row[9] =' . $row[9] . '</br>';
if($thisDay == $apptDay && $timeslot == (int)$row[9])
{ // the appointment date and timeslot matches current slide
echo '<div class="btn btn-secondary btn-sm m-1" style="background:black;" title="Time unavailable">' . $label . '</div>';
}
else
{
echo form_open('AdminForms/booking/' . $dayArray[0] . '/' . $dayArray[1] . '/' . $dayArray[2] . '/' . $timeslot . '/1', $attributes);
echo form_submit("Book",$label,$subAttOpen);
echo form_close();
}
}
}
$placeholder = $day1->modify('+1 day');
$day1 = $placeholder;
}
echo '</div><!-- End of Room 1 data -->';
}
else
{ // no results on query the time frame is wide open
echo '<div class="row" style="width:70%;margin:0 auto;"><h3 class="highlight">Room 1</h3>';
$day1 = $dayStart;
while($day1 <= $dayEnd)
{
$day1format = $day1->format('Y-m-d-H-i-s');
$dayArray = explode('-',$day1format);
for($i = 0;$i <= $slots; $i++)
{
$timeslot = $slotStart + $i;
$label = 'Book: ' . $timeslot . ':00 on ' . $dayArray[1] . '/' . $dayArray[2] . ' ';
echo form_open('AdminForms/booking/' . $dayArray[0] . '/' . $dayArray[1] . '/' . $dayArray[2] . '/' . $timeslot . '/1', $attributes);
echo form_submit("Book",$label,$subAttOpen);
echo form_close();
}
$placeholder = $day1->modify('+1 day');
$day1 = $placeholder;
}
echo '</div><!-- End of Room 1 data -->';
var_dump($dayStart);
}
if(count($r2Data) >= 1)
{ //room 1 has appoints scheduled during the time frame queried
echo '<div class="row" style="width:70%;margin:0 auto;"><h3 class="highlight">Room 2</h3>';
$day2 = $dayStart;
while($day2 <= $dayEnd)
{
$day2format = $day2->format('Y-m-d-H-i-s');
$day2Array = explode('-',$day2format);
for($i = 0;$i <= $slots; $i++)
{
$timeslot = $slotStart + $i;
$label = 'Book: ' . $timeslot . ':00 on ' . $day2Array[1] . '/' . $day2Array[2] . ' ';
foreach($r2Data as $index)
{
$row = explode('-',$index);
//var_dump($row);
$thisDay = $day2Array[0] . '/' . $day2Array[1] . '/' . $day2Array[2];
//echo '$thisDay =' . $thisDay . '</br>';
$apptDay = $row[6] . '/' . $row[7] . '/' . $row[8];
//echo '$apptDay =' . $apptDay . '</br>';
//echo '$timeslot =' . $timeslot . '</br>';
//echo '$row[9] =' . $row[9] . '</br>';
if($thisDay == $apptDay && $timeslot == (int)$row[9])
{ // the appointment date and timeslot matches current slide
echo '<div class="btn btn-secondary btn-sm m-1" style="background:black;" title="Time unavailable">' . $label . '</div>';
}
else
{
echo form_open('AdminForms/booking/' . $day2Array[0] . '/' . $day2Array[1] . '/' . $day2Array[2] . '/' . $timeslot . '/1', $attributes);
echo form_submit("Book",$label,$subAttOpen);
echo form_close();
}
}
}
$placeholder2 = $day2->modify('+1 day');
$day2 = $placeholder2;
}
echo '</div<!-- End of Room 2 data -->';
}
else
{ // no results on query the time frame is wide open
echo '<div class="row" style="width:70%;margin:0 auto;"><h3 class="highlight">Room 2</h3>';
$day2 = $startDate;
while($day2 <= $dayEnd)
{
$day2format = $day2->format('Y-m-d-H-i-s');
$day2Array = explode('-',$day2format);
for($i = 0;$i <= $slots; $i++)
{
$timeslot = $slotStart + $i;
$label = 'Book: ' . $timeslot . ':00 on ' . $day2Array[1] . '/' . $day2Array[2] . ' ';
echo form_open('AdminForms/booking/' . $day2Array[0] . '/' . $day2Array[1] . '/' . $day2Array[2] . '/' . $timeslot . '/1', $attributes);
echo form_submit("Book",$label,$subAttOpen);
echo form_close();
}
$placeholder2 = $day2->modify('+1 day');
$day2 = $placeholder2;
}
echo '</div><!-- End of Room 2 data -->';
}