Allow referencing previously defined named types

Once a named type is defined, in order to reuse that same type it is
needed to reference that type by the name (as in the primitive types).

Add support for NamedTypes in both the schema builder and the schema
generator, which is a way of referencing previously defined named types.

src/Objects/Schema.php

@@ -19,6 +19,7 @@
 use FlixTech\AvroSerializer\Objects\Schema\LocalTimestampMillisType;
 use FlixTech\AvroSerializer\Objects\Schema\LongType;
 use FlixTech\AvroSerializer\Objects\Schema\MapType;
+use FlixTech\AvroSerializer\Objects\Schema\NamedType;
 use FlixTech\AvroSerializer\Objects\Schema\NullType;
 use FlixTech\AvroSerializer\Objects\Schema\RecordType;
 use FlixTech\AvroSerializer\Objects\Schema\StringType;
@@ -71,6 +72,11 @@ public static function string(): StringType
         return new StringType();
     }
 
+    public static function named(string $name): NamedType
+    {
+        return new NamedType($name);
+    }
+
     public static function record(): RecordType
     {
         return new RecordType();

src/Objects/Schema/Generation/SchemaGenerator.php

@@ -18,9 +18,15 @@ class SchemaGenerator
      */
     private $reader;
 
+    /**
+     * @var TypeMapper
+     */
+    private $typeMapper;
+
     public function __construct(SchemaAttributeReader $reader)
     {
         $this->reader = $reader;
+        $this->typeMapper = new TypeMapper($this);
     }
 
     /**
@@ -39,7 +45,7 @@ public function generate(string $className): Schema
      */
     private function generateFromClass(ReflectionClass $class, Type $type): Schema
     {
-        $schema = $this->schemaFromTypes($type);
+        $schema = $this->schemaFromType($type);
 
         if (!$schema instanceof Schema\RecordType) {
             return $schema;
@@ -56,75 +62,20 @@ private function generateFromClass(ReflectionClass $class, Type $type): Schema
     private function schemaFromTypes(Type ...$types): Schema
     {
         if (\count($types) > 1) {
-            $unionSchemas = \array_map(function (Type $type) {
-                return $this->schemaFromTypes($type);
-            }, $types);
+            $unionSchemas = \array_map([$this, 'schemaFromType'], $types);
 
             return Schema::union(...$unionSchemas);
         }
 
-        $type = $types[0];
-        $attributes = $type->getAttributes();
-
-        switch ($type->getTypeName()) {
-            case TypeName::RECORD:
-                if ($attributes->has(AttributeName::TARGET_CLASS)) {
-                    return $this->generate($attributes->get(AttributeName::TARGET_CLASS));
-                }
-                $schema = Schema::record();
-
-                return $this->applyAttributes($schema, $attributes);
-            case TypeName::NULL:
-                $schema = Schema::null();
-
-                return $this->applyAttributes($schema, $attributes);
-            case TypeName::BOOLEAN:
-                $schema = Schema::boolean();
-
-                return $this->applyAttributes($schema, $attributes);
-            case TypeName::INT:
-                $schema = Schema::int();
-
-                return $this->applyAttributes($schema, $attributes);
-            case TypeName::LONG:
-                $schema = Schema::long();
-
-                return $this->applyAttributes($schema, $attributes);
-            case TypeName::FLOAT:
-                $schema = Schema::float();
-
-                return $this->applyAttributes($schema, $attributes);
-            case TypeName::DOUBLE:
-                $schema = Schema::double();
-
-                return $this->applyAttributes($schema, $attributes);
-            case TypeName::BYTES:
-                $schema = Schema::bytes();
-
-                return $this->applyAttributes($schema, $attributes);
-            case TypeName::STRING:
-                $schema = Schema::string();
-
-                return $this->applyAttributes($schema, $attributes);
-            case TypeName::ARRAY:
-                $schema = Schema::array();
-
-                return $this->applyAttributes($schema, $attributes);
-            case TypeName::MAP:
-                $schema = Schema::map();
-
-                return $this->applyAttributes($schema, $attributes);
-            case TypeName::ENUM:
-                $schema = Schema::enum();
-
-                return $this->applyAttributes($schema, $attributes);
-            case TypeName::FIXED:
-                $schema = Schema::fixed();
+        return $this->schemaFromType($types[0]);
+    }
 
-                return $this->applyAttributes($schema, $attributes);
-            default:
-                throw new \InvalidArgumentException('$type is not a valid avro type');
-        }
+    private function schemaFromType(Type $type): Schema
+    {
+        return $this->applyAttributes(
+            $this->typeMapper->toSchema($type),
+            $type->getAttributes()
+        );
     }
 
     private function parseField(ReflectionProperty $property, Schema\RecordType $rootSchema): Schema

src/Objects/Schema/Generation/TypeMapper.php

@@ -0,0 +1,70 @@
+<?php
+
+declare(strict_types=1);
+
+namespace FlixTech\AvroSerializer\Objects\Schema\Generation;
+
+use FlixTech\AvroSerializer\Objects\Schema;
+use FlixTech\AvroSerializer\Objects\Schema\AttributeName;
+use FlixTech\AvroSerializer\Objects\Schema\TypeName;
+
+final class TypeMapper
+{
+    /**
+     * @var array<string, callable>
+     */
+    private $mappers;
+
+    public function __construct(SchemaGenerator $generator)
+    {
+        $this->mappers = [
+            TypeName::RECORD => $this->recordType($generator),
+            TypeName::NULL => $this->simpleType(Schema::null()),
+            TypeName::BOOLEAN => $this->simpleType(Schema::boolean()),
+            TypeName::INT => $this->simpleType(Schema::int()),
+            TypeName::LONG => $this->simpleType(Schema::long()),
+            TypeName::FLOAT => $this->simpleType(Schema::float()),
+            TypeName::DOUBLE => $this->simpleType(Schema::double()),
+            TypeName::BYTES => $this->simpleType(Schema::bytes()),
+            TypeName::STRING => $this->simpleType(Schema::string()),
+            TypeName::ARRAY => $this->simpleType(Schema::array()),
+            TypeName::MAP => $this->simpleType(Schema::map()),
+            TypeName::ENUM => $this->simpleType(Schema::enum()),
+            TypeName::FIXED => $this->simpleType(Schema::fixed()),
+        ];
+    }
+
+    public function toSchema(Type $type): Schema
+    {
+        $mapper = $this->mappers[$type->getTypeName()] ?? $this->namedType();
+
+        return $mapper($type);
+    }
+
+    private function simpleType(Schema $schema): callable
+    {
+        return function () use ($schema): Schema {
+            return $schema;
+        };
+    }
+
+    private function recordType(SchemaGenerator $generator): callable
+    {
+        return function (Type $type) use ($generator): Schema {
+            $attributes = $type->getAttributes();
+
+            if ($attributes->has(AttributeName::TARGET_CLASS)) {
+                return $generator->generate($attributes->get(AttributeName::TARGET_CLASS));
+            }
+
+            return Schema::record();
+        };
+    }
+
+    private function namedType(): callable
+    {
+        return function (Type $type): Schema {
+            return Schema::named($type->getTypeName());
+        };
+    }
+}

src/Objects/Schema/NamedType.php

@@ -0,0 +1,25 @@
+<?php
+
+declare(strict_types=1);
+
+namespace FlixTech\AvroSerializer\Objects\Schema;
+
+use FlixTech\AvroSerializer\Objects\Schema;
+
+class NamedType extends Schema
+{
+    /**
+     * @var string
+     */
+    private $name;
+
+    public function __construct(string $name)
+    {
+        $this->name = $name;
+    }
+
+    public function serialize(): string
+    {
+        return $this->name;
+    }
+}

test/Objects/Schema/Generation/Fixture/RecordWithRecordType.php

@@ -13,10 +13,18 @@
 class RecordWithRecordType
 {
     /**
-     * @SerDe\AvroName("simple")
+     * @SerDe\AvroName("simpleField")
      * @SerDe\AvroType("record", attributes={
-     *     @SerDe\AvroTargetClass("\FlixTech\AvroSerializer\Test\Objects\Schema\Generation\Fixture\SimpleRecord")
+     *     @SerDe\AvroTargetClass("\FlixTech\AvroSerializer\Test\Objects\Schema\Generation\Fixture\SimpleRecord"),
+     *     @SerDe\AvroDoc("This a simple record for testing purposes")
      * })
      */
     private $simpleRecord;
+
+    /**
+     * @SerDe\AvroName("unionField")
+     * @SerDe\AvroType("null")
+     * @SerDe\AvroType("org.acme.SimpleRecord")
+     */
+    private $unionRecord;
 }

test/Objects/Schema/Generation/SchemaGeneratorTest.php

@@ -151,11 +151,23 @@ public function it_should_generate_records_containing_records()
         $expected = Schema::record()
             ->name('RecordWithRecordType')
             ->field(
-                'simple',
+                'simpleField',
                 Schema::record()
                     ->name('SimpleRecord')
                     ->namespace('org.acme')
-                    ->field('intType', Schema::int(), Schema\Record\FieldOption::default(42))
+                    ->doc('This a simple record for testing purposes')
+                    ->field(
+                        'intType',
+                        Schema::int(),
+                        Schema\Record\FieldOption::default(42)
+                    ),
+            )
+            ->field(
+                'unionField',
+                Schema::union(
+                    Schema::null(),
+                    Schema::named('org.acme.SimpleRecord')
+                )
             );
 
         $this->assertEquals($expected, $schema);