Implement JsonDependencyRepository

modules/core/src/main/scala/eu/timepit/scalasteward/dependency/Dependency.scala

@@ -16,8 +16,8 @@
 
 package eu.timepit.scalasteward.dependency
 
-import io.circe.Decoder
 import io.circe.generic.semiauto._
+import io.circe.{Decoder, Encoder}
 
 final case class Dependency(
     groupId: String,
@@ -30,4 +30,7 @@ final case class Dependency(
 object Dependency {
   implicit val dependencyDecoder: Decoder[Dependency] =
     deriveDecoder
+
+  implicit val dependencyEncoder: Encoder[Dependency] =
+    deriveEncoder
 }

modules/core/src/main/scala/eu/timepit/scalasteward/dependency/json/JsonDependencyRepository.scala

@@ -16,22 +16,44 @@
 
 package eu.timepit.scalasteward.dependency.json
 
+import better.files.File
+import cats.MonadError
+import cats.implicits._
 import eu.timepit.scalasteward.application.WorkspaceService
 import eu.timepit.scalasteward.dependency.{Dependency, DependencyRepository}
 import eu.timepit.scalasteward.git.Sha1
 import eu.timepit.scalasteward.github.data.Repo
+import eu.timepit.scalasteward.io.FileService
+import io.circe.parser.decode
+import io.circe.syntax._
 
 class JsonDependencyRepository[F[_]](
+    fileService: FileService[F],
     workspaceService: WorkspaceService[F]
-) extends DependencyRepository[F] {
-
-  workspaceService.root
-
-  // file operations
+)(implicit F: MonadError[F, Throwable])
+    extends DependencyRepository[F] {
 
   override def findSha1(repo: Repo): F[Option[Sha1]] =
-    ???
+    readJson.map(_.store.get(repo).map(_.sha1))
 
   override def setDependencies(repo: Repo, sha1: Sha1, dependencies: List[Dependency]): F[Unit] =
-    ???
+    readJson.flatMap { store =>
+      val updated = store.store.updated(repo, RepoValues(sha1, dependencies))
+      writeJson(Store(updated))
+    }
+
+  def jsonFile: F[File] =
+    workspaceService.root.map(_ / "repos.json")
+
+  def readJson: F[Store] =
+    jsonFile.flatMap { file =>
+      fileService.readFile(file).flatMap { content =>
+        F.fromEither(decode[Store](content))
+      }
+    }
+
+  def writeJson(store: Store): F[Unit] =
+    jsonFile.flatMap { file =>
+      fileService.writeFile(file, store.asJson.toString)
+    }
 }

modules/core/src/main/scala/eu/timepit/scalasteward/dependency/json/RepoValues.scala

@@ -18,5 +18,15 @@ package eu.timepit.scalasteward.dependency.json
 
 import eu.timepit.scalasteward.dependency.Dependency
 import eu.timepit.scalasteward.git.Sha1
+import io.circe.generic.semiauto._
+import io.circe.{Decoder, Encoder}
 
 final case class RepoValues(sha1: Sha1, dependencies: List[Dependency])
+
+object RepoValues {
+  implicit val repoValuesDecoder: Decoder[RepoValues] =
+    deriveDecoder
+
+  implicit val repoValuesEncoder: Encoder[RepoValues] =
+    deriveEncoder
+}

modules/core/src/main/scala/eu/timepit/scalasteward/dependency/json/Store.scala

@@ -17,5 +17,15 @@
 package eu.timepit.scalasteward.dependency.json
 
 import eu.timepit.scalasteward.github.data.Repo
+import io.circe.generic.semiauto._
+import io.circe.{Decoder, Encoder}
 
 final case class Store(store: Map[Repo, RepoValues])
+
+object Store {
+  implicit val storeDecoder: Decoder[Store] =
+    deriveDecoder
+
+  implicit val storeEncoder: Encoder[Store] =
+    deriveEncoder
+}

modules/core/src/main/scala/eu/timepit/scalasteward/git/Sha1.scala

@@ -18,7 +18,7 @@ package eu.timepit.scalasteward.git
 
 import cats.Eq
 import cats.implicits._
-import io.circe.Decoder
+import io.circe.{Decoder, Encoder}
 
 final case class Sha1(value: String)
 
@@ -28,4 +28,7 @@ object Sha1 {
 
   implicit val sha1Decoder: Decoder[Sha1] =
     Decoder[String].map(Sha1.apply)
+
+  implicit val sha1Encoder: Encoder[Sha1] =
+    Encoder[String].contramap(_.value)
 }

modules/core/src/main/scala/eu/timepit/scalasteward/github/data/Repo.scala

@@ -16,9 +16,24 @@
 
 package eu.timepit.scalasteward.github.data
 
+import io.circe.{KeyDecoder, KeyEncoder}
+
 final case class Repo(
     owner: String,
     repo: String
 ) {
   def show: String = s"$owner:$repo"
 }
+
+object Repo {
+  implicit val repoKeyDecoder: KeyDecoder[Repo] =
+    KeyDecoder.instance { key =>
+      val parts = key.split('/')
+      if (parts.length == 2 && parts.forall(_.nonEmpty))
+        Some(Repo(parts(0), parts(1)))
+      else None
+    }
+
+  implicit val repoKeyEncoder: KeyEncoder[Repo] =
+    KeyEncoder.instance(repo => s"${repo.owner}/${repo.repo}")
+}

modules/core/src/main/scala/eu/timepit/scalasteward/io/FileService.scala

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2018 scala-steward contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package eu.timepit.scalasteward.io
+
+import better.files.File
+
+trait FileService[F[_]] {
+  def readFile(file: File): F[String]
+
+  def writeFile(file: File, content: String): F[Unit]
+}