/**
* Tell whether the current state of the date is valid for a GedcomX formal date.
* In particular, make sure it follows one of the following patterns:
* [A]simpleDate
* [A]simpleDate/[simpleDate|Duration]
* [A]/simpleDate
* R[repetitions]/simpleDate/(simpleDate|Duration)
* @return bool
*/
public function isValid()
{
if ($this->isRecurring) {
return !$this->isApproximate && $this->start !== null && $this->start->isValid() && ($this->end !== null && $this->end->isValid() || $this->end === null && $this->duration !== null && $this->duration->isValid());
} else {
if ($this->numRepetitions !== null) {
return false;
}
if ($this->start !== null && !$this->isRange) {
return $this->end === null && $this->duration === null && $this->start->isValid();
}
if ($this->isRange) {
if ($this->start === null) {
return $this->end !== null && $this->end->isValid() && $this->duration === null;
} else {
return ($this->end === null || $this->duration === null) && ($this->end === null || $this->end->isValid()) && ($this->duration === null || $this->duration->isValid());
}
}
}
return false;
}
