From 8315493e376692e61aa7ee464f2948306f32618d Mon Sep 17 00:00:00 2001
From: Theodore Brown <theodorejb@outlook.com>
Date: Fri, 22 Dec 2023 15:37:27 -0600
Subject: [PATCH] Support counting the rows that match a filter without
 selecting them

---
 CHANGELOG.md            |  8 +++++++-
 src/Entities.php        | 18 ++++++++++++++++++
 src/RouteHandler.php    | 29 +++++++++++++++++++++++++++++
 test/EntitiesDbTest.php | 20 ++++++++++++++++++++
 4 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3847383..91b7ab6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [2.8.0] - 2023-12-22
+### Added
+- `countEntities()` method and corresponding `count()` route handler.
+This allows counting the rows that match a query/filter without selecting them.
+
 ## [2.7.0] - 2023-09-27
 ### Added
 - `writableId` bool property to optionally make the ID column writable.
@@ -146,7 +151,8 @@ return early if passed an empty IDs array.
 ### Changed
 - Initial stable release
 
-[Unreleased]: https://github.com/theodorejb/phaster/compare/v2.7.0...HEAD
+[Unreleased]: https://github.com/theodorejb/phaster/compare/v2.8.0...HEAD
+[2.8.0]: https://github.com/theodorejb/phaster/compare/v2.7.0...v2.8.0
 [2.7.0]: https://github.com/theodorejb/phaster/compare/v2.6.0...v2.7.0
 [2.6.0]: https://github.com/theodorejb/phaster/compare/v2.5.0...v2.6.0
 [2.5.0]: https://github.com/theodorejb/phaster/compare/v2.4.0...v2.5.0
diff --git a/src/Entities.php b/src/Entities.php
index 745eae1..31cda30 100644
--- a/src/Entities.php
+++ b/src/Entities.php
@@ -345,6 +345,24 @@ public function getEntities(array $filter = [], array $fields = [], array $sort
         return Helpers::mapRows($select->query()->getIterator(), $fieldProps);
     }
 
+    public function countEntities(array $filter = []): int
+    {
+        $processedFilter = $this->processFilter($filter);
+        $selectMap = Helpers::propMapToSelectMap($this->fullPropMap);;
+
+        $prop = new Prop('count', 'COUNT(*)', false, true, 'count');
+        $queryOptions = new QueryOptions($processedFilter, $filter, [], [$prop]);
+
+        /** @psalm-suppress MixedArgumentTypeCoercion */
+        $select = $this->db->select($this->getBaseSelect($queryOptions))
+            ->where(self::propertiesToColumns($selectMap, $processedFilter));
+
+        /** @var array{count: int} $row */
+        $row = $select->query()->getFirst();
+
+        return $row['count'];
+    }
+
     /**
      * Converts nested properties to an array of columns and values using a map.
      * @return array<string, mixed>
diff --git a/src/RouteHandler.php b/src/RouteHandler.php
index 5b1c6c1..b935cd2 100644
--- a/src/RouteHandler.php
+++ b/src/RouteHandler.php
@@ -101,6 +101,35 @@ public function search(string $class, int $defaultLimit = 25, int $maxLimit = 10
         };
     }
 
+    /**
+     * @param class-string<Entities> $class
+     */
+    public function count(string $class): callable
+    {
+        $factory = $this->entitiesFactory;
+
+        return function (ServerRequestInterface $request, ResponseInterface $response) use ($class, $factory): ResponseInterface {
+            $query = [];
+
+            foreach ($request->getQueryParams() as $param => $value) {
+                if ($param !== 'q') {
+                    throw new HttpException("Unrecognized parameter '{$param}'", StatusCode::BAD_REQUEST);
+                }
+                if (!is_array($value)) {
+                    throw new HttpException("Parameter '{$param}' must be an array", StatusCode::BAD_REQUEST);
+                }
+
+                $query = $value;
+            }
+
+            $instance = $factory->createEntities($class);
+            $count = $instance->countEntities($query);
+
+            $response->getBody()->write(json_encode(['count' => $count]));
+            return $response->withHeader('Content-Type', 'application/json');
+        };
+    }
+
     /**
      * @param class-string<Entities> $class
      */
diff --git a/test/EntitiesDbTest.php b/test/EntitiesDbTest.php
index 1f28dfb..ff3da39 100644
--- a/test/EntitiesDbTest.php
+++ b/test/EntitiesDbTest.php
@@ -291,6 +291,26 @@ public function testGetEntities(Entities $entities): void
         $this->assertSame($expected, $actual);
     }
 
+    /**
+     * @dataProvider entitiesProvider
+     */
+    public function testCountEntities(Entities $entities): void
+    {
+        $users = [];
+
+        for ($i = 1; $i <= 20; $i++) {
+            $users[] = [
+                'name' => "Count user {$i}",
+                'birthday' => '2000-03-04',
+                'weight' => $i * 10,
+            ];
+        }
+
+        $entities->addEntities($users);
+        $actual = $entities->countEntities(['weight' => ['le' => 100], 'name' => ['lk' => 'Count user %']]);
+        $this->assertSame(10, $actual);
+    }
+
     /**
      * @dataProvider legacyUsersProvider
      */