From a937e7fde010cc8804f8659f82fcc93df7b6ed2b Mon Sep 17 00:00:00 2001
From: Unay Santisteban <usantisteban@othercode.io>
Date: Fri, 26 Jan 2024 16:56:31 +1000
Subject: [PATCH] Feature/Add page number support. (#20)

---
 README.md              | 11 +++++------
 src/Criteria.php       | 11 ++++++++++-
 src/Page.php           | 14 +++++++++++---
 tests/CriteriaTest.php | 10 +++++++++-
 4 files changed, 35 insertions(+), 11 deletions(-)

diff --git a/README.md b/README.md
index 62aecfb..067fa78 100644
--- a/README.md
+++ b/README.md
@@ -32,8 +32,8 @@ $criteria = Criteria::default()
     ->withFilterGroup($g1)
     ->withOrderBy('surname')
     ->withOrderType('asc')
-    ->withPageLimit(10)
-    ->withPageOffset(5);
+    ->withPageLimit(25)
+    ->withPageOffset(50);
 
 $users = $repository->match($criteria);
 
@@ -45,8 +45,8 @@ $criteria = Criteria::default()
         ->addFilterIn('country', ['es', 'fr']))
     ->withOrderBy('surname')
     ->withOrderType('asc')
-    ->withPageLimit(10)
-    ->withPageOffset(5);
+    ->withPageLimit(25)
+    ->withPageOffset(50);
 
 // In SQL, we may have something like:
 // WHERE status = 1 AND followers >= 700 AND country in ('es', 'fr')
@@ -66,6 +66,5 @@ $criteria = Criteria::default()
     ->withFilterGroup(FilterGroup::create()->addFilterContains('content', $term))
     ->withOrderBy('created_at')
     ->withOrderType(Order::TYPE_ASC)
-    ->withPageLimit(10)
-    ->withPageOffset(5);
+    ->withPageNumber(3);
 ```
diff --git a/src/Criteria.php b/src/Criteria.php
index 995bbcb..3964a2e 100644
--- a/src/Criteria.php
+++ b/src/Criteria.php
@@ -110,7 +110,7 @@ public function withFilterGroups(array $groups): self
      * Returns a new instance of the criteria adding the given FilterGroup.
      *
      * @param  FilterGroup|Closure  $group
-     * @return $this
+     * @return Criteria
      */
     public function withFilterGroup(FilterGroup|Closure $group): self
     {
@@ -175,6 +175,15 @@ public function withPageLimit(int $limit): self
         );
     }
 
+    public function withPageNumber(int $number, int $size = null): self
+    {
+        return self::create(
+            groups: $this->groups,
+            order: $this->order,
+            page: Page::number($number, is_null($size) ? $this->page->limit() : $size)
+        );
+    }
+
     /**
      * Returns the list of group filters.
      *
diff --git a/src/Page.php b/src/Page.php
index 28d4b21..d41953c 100644
--- a/src/Page.php
+++ b/src/Page.php
@@ -17,6 +17,9 @@ final class Page implements ValueObject
 {
     use IsValueObject;
 
+    const DEFAULT_LIMIT = 25;
+    const DEFAULT_OFFSET = 0;
+
     /**
      * Page constructor.
      *
@@ -24,17 +27,22 @@ final class Page implements ValueObject
      * @param  int  $offset
      */
     public function __construct(
-        private readonly int $limit = 25,
-        private readonly int $offset = 0,
+        private readonly int $limit = self::DEFAULT_LIMIT,
+        private readonly int $offset = self::DEFAULT_OFFSET,
     ) {
         $this->check();
     }
 
-    public static function create(int $limit = 25, int $offset = 0): self
+    public static function create(int $limit = self::DEFAULT_LIMIT, int $offset = self::DEFAULT_OFFSET): self
     {
         return new self($limit, $offset);
     }
 
+    public static function number(int $number, int $size = self::DEFAULT_LIMIT): self
+    {
+        return self::create($size, ($size * $number) - $size);
+    }
+
     protected function invariantLimitValueMustBePositive(): bool
     {
         return $this->limit >= 0;
diff --git a/tests/CriteriaTest.php b/tests/CriteriaTest.php
index d0c2e4f..6d117a4 100644
--- a/tests/CriteriaTest.php
+++ b/tests/CriteriaTest.php
@@ -144,4 +144,12 @@ public function pageOffset(): int
         ->withOrderType('asc');
 
     expect($c->__toString())->toBe('name.=.Vincent+age.>=.35#name.asc#100.0');
-});
\ No newline at end of file
+});
+
+test('Criteria should configure limit and offset using page number', function () {
+    $c = Criteria::default()
+        ->withPageNumber(3, 25);
+
+    expect($c->page()->limit())->toBe(25)
+        ->and($c->page()->offset())->toBe(50);
+});