Php Stored date from MySQL db convert to equivalent Ethiopian date - php

Question

I want to convert any Gregorian date to an equivalent Ethiopian Date. The Gregorian date is generated on records created or updated using the PHP date function, date('Y-m-d H:i:s') from the server date. I want to show the changes made are in the Ethiopian date so the views are can easily understand it. I've made a function to change it. but the function date is not reliable in some leap years.
The function returns the date format in either Tigrigna or Amharic language.
Any hint?
function conver_to_ethiopian_date($date, $lang ="ti"){
$OFFSET=79372;
$DAY=86400;
$EYear=1745;
$EMonth=0;
$EDate=0;
$GC=0;
$timezone = 0;
$tot= gmdate($date, 3600*($timezone+date("I")));
$days=round(strtotime($tot)/$DAY);
$days +=$OFFSET;
$mark=0;
$EYear=1745;
while ($mark==0){
if ($EYear % 4 ==3){
if ($days>=366) {
$days-=366;
$EYear=$EYear+1;
}
else{
$mark=1;
}
}
else{
if ($days>=365){
$days-=365;
$EYear=$EYear+1;
}
else {$mark=1;}
}
}
if ($days==0){
$EYear-=1;
//leap year
$EMonth=12;
$EDate=5 + (($EYear%4==3)?1:0);
}
else{
$EMonth = (($days-1) / 30);
if ($days % 30 ==0){ $EDate = 30;}
else {$EDate=$days % 30;}
}
$months_am =array("መስከረም", "ጥቅምት", "ኅዳር", "ታኅሣሥ", "ጥር","የካቲት","መጋቢት","ሚያዝያ", "ግንቦት", "ሰኔ", "ሐምሌ", "ነሐሴ", 'ጳጉሜ');
$months_tg =array("መስከረም", "ጥቅምቲ", "ሕዳር", "ታሕሳስ", "ጥሪ","የካቲት","መጋቢት","ሚያዝያ", "ጉንበት", "ሰነ", "ሓምለ", "ነሓሰ", 'ጳጉሜን');
$days_am =array("እሁድ", "ሰኞ", "ማክሰኞ", "ሮብ", "ሓሙስ", "ኣርብ", "ቀዳሜ");
$days_tg =array("ሰንበት", "ሶኒ", "ሰሉስ", "ረቡዕ", "ሓሙስ", "ዓርቢ", "ቀዳም");
$date_time = explode(' - ', $date);
$year =$year?$year:date("Y") ;
$day_of_week = date("w", mktime(0, 0, 0, $date_time[1], $date_time[2], $date_time[0]));
if ("am" == $lang)
return $days_am[$day_of_week]." ".$months_am[$EMonth]." ".$EDate.", ".$EYear;
else
return $days_tg[$day_of_week]." ".$months_tg[$EMonth]." ". $EDate.", ".$EYear;
}