From 18f21d9438ccb39f0cd567f5a0e83cbb3427488f Mon Sep 17 00:00:00 2001
From: vlad <vlad@drivergrp.com>
Date: Thu, 1 Dec 2016 21:44:31 -0800
Subject: Useful abstractions to craft DALs

---
 src/main/scala/xyz/driver/core/database.scala | 54 ++++++++++++++++++++++++++-
 1 file changed, 53 insertions(+), 1 deletion(-)

(limited to 'src/main/scala')

diff --git a/src/main/scala/xyz/driver/core/database.scala b/src/main/scala/xyz/driver/core/database.scala
index f846b15..3f4af40 100644
--- a/src/main/scala/xyz/driver/core/database.scala
+++ b/src/main/scala/xyz/driver/core/database.scala
@@ -5,7 +5,8 @@ import slick.dbio.{DBIOAction, NoStream}
 import slick.driver.JdbcProfile
 import xyz.driver.core.time.Time
 
-import scala.concurrent.Future
+import scala.concurrent.{ExecutionContext, Future}
+import scalaz.Monad
 
 object database {
 
@@ -56,4 +57,55 @@ object database {
     def createTables(): Future[Unit] = Future.successful(())
     def disconnect(): Unit           = {}
   }
+
+  trait Dal {
+
+    type T[_]
+    implicit val monadT: Monad[T]
+
+    def execute[D](operations: T[D]): Future[D]
+    def executeTransaction[D](operations: T[D]): Future[D]
+    def noAction[V](v: V): T[V]
+    def customAction[R](action: => Future[R]): T[R]
+  }
+
+  class FutureDal(executionContext: ExecutionContext) extends Dal {
+
+    implicit val exec = executionContext
+
+    override type T[_] = Future[_]
+    implicit val monadT: Monad[T] = new Monad[T] {
+      override def point[A](a: => A): T[A]                  = Future(a)
+      override def bind[A, B](fa: T[A])(f: A => T[B]): T[B] = fa.flatMap(a => f(a.asInstanceOf[A]))
+    }
+
+    def execute[D](operations: T[D]): Future[D]            = operations.asInstanceOf[Future[D]]
+    def executeTransaction[D](operations: T[D]): Future[D] = operations.asInstanceOf[Future[D]]
+    def noAction[V](v: V): T[V]                            = Future.successful(v)
+    def customAction[R](action: => Future[R]): T[R]        = action
+  }
+
+  class SlickDal(database: Database, executionContext: ExecutionContext) extends Dal {
+
+    import database.profile.api._
+
+    implicit val exec = executionContext
+
+    override type T[_] = slick.dbio.DBIO[_]
+    val monadT: Monad[T] = new Monad[T] {
+      override def point[A](a: => A): T[A]                  = DBIO.successful(a)
+      override def bind[A, B](fa: T[A])(f: A => T[B]): T[B] = fa.flatMap(a => f(a.asInstanceOf[A]))
+    }
+
+    def execute[D](operations: T[D]): Future[D] = {
+      database.database.run(operations.asInstanceOf[slick.dbio.DBIO[D]])
+    }
+
+    def executeTransaction[D](readOperations: T[D]): Future[D] = {
+      database.database.run(readOperations.asInstanceOf[slick.dbio.DBIO[D]].transactionally)
+    }
+
+    def noAction[V](v: V): slick.dbio.DBIO[V]       = DBIO.successful(v)
+    def customAction[R](action: => Future[R]): T[R] = DBIO.from(action)
+  }
 }
-- 
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