function next_depreciation_date($depreciation_date) {
$start = strtotime($depreciation_date);
$y = date('Y', $start);
$m = date('n', $start) + 1;
if ($m > 12) {
$m = 1;
$y++;
}
return strtotime("$y-$m-1");
}
function depreciation_months($depreciation_start) {
// assume that depreciation start is the same fiscal year
//$start = strtotime($depreciation_start);
//$end = strtotime($year['end']);
$start = next_depreciation_date($depreciation_start);
return 12 - date('n', $start) + 1;
//$d1 = date('j', $start); // day of the month
//$d2 = date('t', $start); // number of days in month
//if ($d2 > $d1)
//$months++;
}
function months_between_dates($start, $end) {
$start = strtotime($start);
$end = strtotime($end);
$y1 = date('Y', $start);
$m1 = date('n', $start);
$y2 = date('Y', $end);
$m2 = date('n', $end);
return 12 * ($y2 - $y1) + $m2 - $m1;
}
function compute_gl_rows_for_depreciation($item, $no_months, $period) {
$rows = array();
$year = get_current_fiscalyear();
$y = date('Y', strtotime($year['end']));
switch ($item['depreciation_method']) {
case 'D':
$line_value = $item['purchase_cost']*$item['depreciation_rate']/100/12;
$value = $item['material_cost'] * $item['depreciation_rate'] * $item['depreciation_factor']/100/12;
if ($value < $line_value)
$value = $line_value;
break;
case 'S': // purchase_cost stores start cost of item
$done_months = months_between_dates($item['depreciation_start'], $item['depreciation_date']);
$remaining_months = 12.0 * 100.0/$item['depreciation_rate'] - $done_months;
$value = $item['purchase_cost']*$item['depreciation_rate']/100/12;
break;
case 'N':
$N = $item['depreciation_rate'];
$done_years = months_between_dates($item['depreciation_start'], $item['depreciation_date'])/12;
$value = $item['purchase_cost']* ($N-$done_years)/($N*($N+1)/2)/12;
break;
case 'O':
$value = $item['material_cost'];
break;
}
$next = next_depreciation_date($item['depreciation_date']);
$m = date('n', $next);
$total = 0;
$cnt = 0;
for ($i=$m; $i < $m + $no_months; $i++) {
if ($item['depreciation_method'] == 'S') {
if ($cnt >= $remaining_months)
$value = 0;
}
$date = sql2date(date("$y-$i-t", strtotime("$y-$i-1")));
$total += $value;
if (FA_YEARLY == $period) {
// yearly
if ($i == $m + $no_months - 1)
$rows[] = array('date' => $date, 'value' => $total);
/*else
$rows[] = array('date' => $date, 'value' => 0);
*/
}
else {
// monthly
$rows[] = array('date' => $date, 'value' => $value);
}
$cnt++;
if ($item['depreciation_method'] == 'O') {
// depreciate only in the first month
$value = 0;
}
}
return $rows;
}
