Add date class (#46)

* To allow dates to be represented, introduce date class

* To provide testing for the Date class, import unit test

* To complete the import of the Date class into the Clock library, tweak dependnecies, namespacing etc.

* To enable us to use the new Date class, add the ability for a Clock to return a Date object

* Make class final

Co-authored-by: Ben Challis <[email protected]>

Co-authored-by: Zoran Antolović <[email protected]>
Co-authored-by: Ben Challis <[email protected]>

lib/Clock.php

@@ -19,4 +19,6 @@ public function now(): \DateTimeImmutable;
      * prevent unintended side effects.
      */
     public function nowMutable(): \DateTime;
+
+    public function today(): Date;
 }

lib/Date.php

@@ -0,0 +1,148 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Lendable\Clock;
+
+use Lendable\Clock\Date\InvalidDate;
+
+final class Date
+{
+    private int $year;
+
+    private int $month;
+
+    private int $day;
+
+    private function __construct(int $year, int $month, int $day)
+    {
+        if (!checkdate($month, $day, $year)) {
+            throw InvalidDate::fromDate($year, $month, $day);
+        }
+
+        $this->year = $year;
+        $this->month = $month;
+        $this->day = $day;
+    }
+
+    public static function fromYearMonthDay(int $year, int $month, int $day): self
+    {
+        return new self($year, $month, $day);
+    }
+
+    public static function fromDateTime(\DateTimeInterface $dateTime): self
+    {
+        return new self(
+            (int) $dateTime->format('Y'),
+            (int) $dateTime->format('m'),
+            (int) $dateTime->format('d')
+        );
+    }
+
+    public static function fromYearMonthDayString(string $value): self
+    {
+        $result = preg_match('/^(\d{4})-(\d{1,2})-(\d{1,2})$/', $value, $matches);
+
+        if ($result === 0) {
+            throw new InvalidDate('Failed to parse string as a Y-m-d formatted date.');
+        }
+
+        return self::fromYearMonthDay(
+            (int) $matches[1],
+            (int) $matches[2],
+            (int) $matches[3]
+        );
+    }
+
+    public static function fromYearsAgo(int $yearsAgo): self
+    {
+        $dob = new \DateTimeImmutable("today - $yearsAgo years");
+
+        return self::fromDateTime($dob);
+    }
+
+    public function year(): int
+    {
+        return $this->year;
+    }
+
+    public function month(): int
+    {
+        return $this->month;
+    }
+
+    public function day(): int
+    {
+        return $this->day;
+    }
+
+    public function equals(self $other): bool
+    {
+        return $this->year === $other->year
+            && $this->month === $other->month
+            && $this->day === $other->day;
+    }
+
+    public function isBefore(self $other): bool
+    {
+        return $this->toDateTime() < $other->toDateTime();
+    }
+
+    public function isBeforeOrEqualTo(self $other): bool
+    {
+        return $this->isBefore($other) || $this->equals($other);
+    }
+
+    public function isAfter(self $other): bool
+    {
+        return $this->toDateTime() > $other->toDateTime();
+    }
+
+    public function isBetween(self $start, self $end): bool
+    {
+        return !$this->isBefore($start) && !$this->isAfter($end);
+    }
+
+    public function toDateTime(): \DateTimeImmutable
+    {
+        $dateTime = \DateTimeImmutable::createFromFormat(
+            'Y-m-d H:i:s',
+            sprintf('%d-%d-%d 00:00:00', $this->year, $this->month, $this->day),
+        );
+        \assert($dateTime instanceof \DateTimeImmutable);
+
+        return $dateTime;
+    }
+
+    public function toYearMonthDayString(): string
+    {
+        return sprintf('%d-%02d-%02d', $this->year, $this->month, $this->day);
+    }
+
+    public function diff(self $other): \DateInterval
+    {
+        return $this->toDateTime()->diff($other->toDateTime());
+    }
+
+    public function differenceInDays(self $other): int
+    {
+        return (int) $this->diff($other)->format('%a');
+    }
+
+    public function dayAfter(): self
+    {
+        return $this->modify('+1 days');
+    }
+
+    public function dayBefore(): self
+    {
+        return $this->modify('-1 days');
+    }
+
+    private function modify(string $modification): self
+    {
+        $modified = $this->toDateTime()->modify($modification);
+
+        return self::fromDateTime($modified);
+    }
+}

lib/Date/InvalidDate.php

@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Lendable\Clock\Date;
+
+final class InvalidDate extends \InvalidArgumentException
+{
+    public static function fromDate(int $year, int $month, int $day): self
+    {
+        return new self(sprintf('Date %d-%d-%d (Y-m-d) is invalid.', $year, $month, $day));
+    }
+}

lib/FixedClock.php

@@ -32,4 +32,9 @@ public function changeTimeTo(\DateTimeInterface $time): void
     {
         $this->now = DateTimeNormalizer::immutable($time);
     }
+
+    public function today(): Date
+    {
+        return Date::fromDateTime($this->now());
+    }
 }

lib/PersistedFixedClock.php

@@ -60,6 +60,11 @@ public function nowMutable(): \DateTime
         return $this->delegate->nowMutable();
     }
 
+    public function today(): Date
+    {
+        return Date::fromDateTime($this->now());
+    }
+
     public function changeTimeTo(\DateTimeInterface $time): void
     {
         $this->delegate->changeTimeTo($time);

lib/SystemClock.php

@@ -27,4 +27,9 @@ public function nowMutable(): \DateTime
     {
         return \DateTime::createFromImmutable($this->now());
     }
+
+    public function today(): Date
+    {
+        return Date::fromDateTime($this->now());
+    }
 }