greeting

greeting.php

<?php

class Client
{
    public $greetingRules = [];

    public function __construct()
    {
        $this->greetingRules[] = new MorningGreeting();
        $this->greetingRules[] = new AfternoonGreeting();
        $this->greetingRules[] = new EveningGreeting();
    }

    /**
     * @param int $hour
     */
    public function getGreeting($hour)
    {
        /**
         * @var $greetingRule GreetingRule
         */
        foreach ($this->greetingRules as $greetingRule) {
            if ($greetingRule->isRight($hour)) {
                return $greetingRule->getGreeting();
            }
        }
        throw new Exception("Error when greeting!");
    }
}

class MorningGreeting implements GreetingRule
{
    public function getGreeting()
    {
        return "Good Morning";
    }

    public function isRight($hour)
    {
        if ($hour >= 6 && $hour < 12) {
            return true;
        }
        return false;
    }
}

class AfternoonGreeting implements GreetingRule
{
    public function getGreeting()
    {
        return "Good Afternoon";
    }

    public function isRight($hour)
    {
        if ($hour >= 12 && $hour < 18) {
            return true;
        }
        return false;
    }
}

class EveningGreeting implements GreetingRule
{
    public function getGreeting()
    {
        return "Good Evening";
    }

    public function isRight($hour)
    {
        if ($hour >= 18 && $hour < 22) {
            return true;
        }
        return false;
    }
}

interface GreetingRule
{
    /**
     * @param int $hour
     * @return bool
     */
    public function isRight($hour);

    /**
     * @return string
     */
    public function getGreeting();
}

$client = new Client();

echo $client->getGreeting(7) . PHP_EOL;
echo $client->getGreeting(13) . PHP_EOL;
echo $client->getGreeting(19) . PHP_EOL;