/**
* Calculates rating points exchange between teams and returns it.
*
* @return float the points exchange
* @throws InvalidMatchResultException if cannot determine match result
*/
public function calculate()
{
$base = $this->ratingsGap / Calculate::MAX_RATINGS_GAP;
if ($this->matchResult->isUnderdogWin() || $this->matchResult->equalsWin()) {
$this->exchangeAmount = 1 + $base;
$this->applyWeightings();
return $this->exchangeAmount;
}
if ($this->matchResult->isHigherTeamWin()) {
$this->exchangeAmount = 1 - $base;
$this->applyWeightings();
return $this->exchangeAmount;
}
if ($this->matchResult->getResult() == MatchResult::DRAW) {
$this->exchangeAmount = $base;
$this->applyWeightings();
return $this->exchangeAmount;
}
throw new InvalidMatchResultException('Cannot calculate exchange: Invalid MatchResult Type');
}
