feat(server): Implement get company by id (#13)

modules/server/src/main/scala/io/kevchuang/reviewboard/domain/company.scala

@@ -111,6 +111,13 @@ object company:
       DeriveJsonCodec.gen[CompanyAlreadyExists]
   end CompanyAlreadyExists
 
+  final case class CompanyNotFound(companyId: CompanyId)
+      extends CompanyDomainError
+  object CompanyNotFound:
+    given JsonCodec[CompanyNotFound] =
+      DeriveJsonCodec.gen[CompanyNotFound]
+  end CompanyNotFound
+
   final case class UnableToGenerateCompanyId(message: String)
       extends CompanyDomainError
   object UnableToGenerateCompanyId:

modules/server/src/main/scala/io/kevchuang/reviewboard/http/endpoints/GetCompanyByIdEndpoint.scala

@@ -0,0 +1,37 @@
+package io.kevchuang.reviewboard.http.endpoints
+
+import io.kevchuang.reviewboard.domain.company.*
+import io.kevchuang.reviewboard.services.company.CompanyService
+import io.kevchuang.reviewboard.services.db.DatabaseService
+import sttp.model.StatusCode
+import sttp.tapir.*
+import sttp.tapir.json.zio.*
+import sttp.tapir.generic.auto.*
+import sttp.tapir.codec.iron.{*, given}
+import zio.ZIO
+
+final case class GetCompanyByIdEndpoint()
+    extends HttpEndpoint[
+      DatabaseService & CompanyService,
+      CompanyId,
+      CompanyNotFound,
+      Company
+    ]:
+
+  override def endpointDescription
+      : ApiEndpoint[CompanyId, CompanyNotFound, Company] =
+    endpoint
+      .tag("companies")
+      .name("getById")
+      .description("get company by its id")
+      .in("companies" / path[CompanyId]("companyId"))
+      .get
+      .errorOut(jsonBody[CompanyNotFound])
+      .out(jsonBody[Company])
+
+  override def endpointLogic: CompanyId => ZIO[
+    DatabaseService & CompanyService,
+    CompanyNotFound,
+    Company
+  ] = CompanyService.getCompanyById
+end GetCompanyByIdEndpoint

modules/server/src/main/scala/io/kevchuang/reviewboard/services/company/CompanyService.scala

@@ -8,8 +8,10 @@ trait CompanyService:
   def createCompany(
       company: CreateCompany
   ): ZIO[DatabaseService, CompanyDomainError, Company]
-
   def getCompanies: URIO[DatabaseService, List[Company]]
+  def getCompanyById(
+      companyId: CompanyId
+  ): ZIO[DatabaseService, CompanyNotFound, Company]
 end CompanyService
 
 object CompanyService:
@@ -21,4 +23,9 @@ object CompanyService:
   def getCompanies
       : ZIO[DatabaseService & CompanyService, Nothing, List[Company]] =
     ZIO.serviceWithZIO[CompanyService](_.getCompanies)
+
+  def getCompanyById(
+      companyId: CompanyId
+  ): ZIO[DatabaseService & CompanyService, CompanyNotFound, Company] =
+    ZIO.serviceWithZIO[CompanyService](_.getCompanyById(companyId))
 end CompanyService

modules/server/src/main/scala/io/kevchuang/reviewboard/services/company/CompanyServiceLive.scala

@@ -20,5 +20,13 @@ object CompanyServiceLive:
 
       override def getCompanies: URIO[DatabaseService, List[Company]] =
         DatabaseService.getCompanies
+
+      override def getCompanyById(
+          companyId: CompanyId
+      ): ZIO[DatabaseService, CompanyNotFound, Company] =
+        DatabaseService
+          .getCompany(companyId)
+          .flatMap(ZIO.fromOption)
+          .orElseFail(CompanyNotFound(companyId))
   )
 end CompanyServiceLive

modules/server/src/main/scala/io/kevchuang/reviewboard/services/db/DatabaseService.scala

@@ -7,6 +7,7 @@ trait DatabaseService:
   def countCompanies: UIO[Long]
   def existsCompany(companyName: CompanyName): UIO[Boolean]
   def getCompanies: UIO[List[Company]]
+  def getCompany(companyId: CompanyId): UIO[Option[Company]]
   def insertCompany(company: Company): UIO[Unit]
 end DatabaseService
 
@@ -22,6 +23,9 @@ object DatabaseService:
   def getCompanies: URIO[DatabaseService, List[Company]] =
     ZIO.serviceWithZIO[DatabaseService](_.getCompanies)
 
+  def getCompany(companyId: CompanyId): URIO[DatabaseService, Option[Company]] =
+    ZIO.serviceWithZIO[DatabaseService](_.getCompany(companyId))
+
   def insertCompany(
       company: Company
   ): URIO[DatabaseService, Unit] =

modules/server/src/main/scala/io/kevchuang/reviewboard/services/db/InMemoryDatabase.scala

@@ -16,6 +16,9 @@ final case class InMemoryDatabase(database: mutable.Map[CompanyId, Company])
   override def getCompanies: UIO[List[Company]] =
     ZIO.succeed(database.values.toList)
 
+  override def getCompany(companyId: CompanyId): UIO[Option[Company]] =
+    ZIO.succeed(database.get(companyId))
+
   override def insertCompany(
       company: Company
   ): UIO[Unit] =

modules/server/src/test/scala/io/kevchuang/reviewboard/services/company/CompanyServiceSpec.scala

@@ -10,7 +10,7 @@ import io.kevchuang.reviewboard.services.db.{DatabaseService, InMemoryDatabase}
 
 object CompanyServiceSpec extends ZIOSpecDefault:
   override def spec: Spec[TestEnvironment with Scope, Any] =
-    createCompanySuite + getCompaniesSuite
+    (createCompanySuite + getCompaniesSuite + getCompanyByIdSuite)
 
   private lazy val createCompanySuite =
     suite("createCompany")(
@@ -30,7 +30,7 @@ object CompanyServiceSpec extends ZIOSpecDefault:
           exists  <- DatabaseService.existsCompany(companyName)
         yield assertTrue(company == expected, exists)
         end for
-      }.provide(InMemoryDatabase.live, CompanyServiceLive.live)
+      }.provide(CompanyServiceLive.live, InMemoryDatabase.live)
     )
 
   private lazy val getCompaniesSuite =
@@ -66,6 +66,32 @@ object CompanyServiceSpec extends ZIOSpecDefault:
             hasSameElements(List(expectedFirstCompany, expectedSecondCompany))
           )
         end for
-      }.provide(InMemoryDatabase.live, CompanyServiceLive.live)
+      }.provide(CompanyServiceLive.live, InMemoryDatabase.live)
+    )
+
+  private lazy val getCompanyByIdSuite =
+    suite("getCompanyById")(
+      test("should return company by giving its id") {
+        val company = DataGenerator.generateCreateCompany(
+          CompanyName("RockTheJVM"),
+          Url("rockthejvm.com")
+        )
+        val expectedCompany = DataGenerator.generateCompany(
+          id = CompanyId(1),
+          slug = CompanySlug("rockthejvm"),
+          name = CompanyName("RockTheJVM"),
+          url = Url("rockthejvm.com")
+        )
+        for
+          _      <- CompanyService.createCompany(company)
+          result <- CompanyService.getCompanyById(CompanyId(1))
+        yield assertTrue(result == expectedCompany)
+        end for
+      }.provide(CompanyServiceLive.live, InMemoryDatabase.live),
+      test("should return CompanyNotFound if company id was not found") {
+        assertZIO(CompanyService.getCompanyById(CompanyId(1)).exit)(
+          fails(equalTo(CompanyNotFound(CompanyId(1))))
+        )
+      }.provide(CompanyServiceLive.live, InMemoryDatabase.live)
     )
 end CompanyServiceSpec