Change config path

Closes #116.

README.md

@@ -31,7 +31,7 @@ This will create a launcher at `./target/universal/stage/bin/spotify-next`.
 ## Usage
 
 The application requires some configuration (e.g. the client ID for the Spotify Web API).
-It's stored in a file at `~/.spotify-next.json`.
+It's stored in a file at `$XDG_CONFIG_HOME/spotify-next/config.json` or `$HOME/.config/spotify-next/config.json` (whichever works first).
 When you first run the application, or if that file is deleted, the application will ask and attempt to create one.
 
 The configuration defines the port for the embedded HTTP server used for authentication. The server will only start when the login flow is triggered, and stop afterwards.

src/main/scala/com/kubukoz/next/ConfigLoader.scala

@@ -14,6 +14,7 @@ import cats.effect.std.Console
 import fs2.io.file.Files
 import cats.FlatMap
 import cats.MonadThrow
+import fs2.Pipe
 
 trait ConfigLoader[F[_]] {
   def saveConfig(config: Config): F[Unit]
@@ -58,9 +59,9 @@ object ConfigLoader {
   def default[F[_]: Files: MonadThrow](configPath: Path)(using fs2.Compiler[F, F]): ConfigLoader[F] =
     new ConfigLoader[F] {
 
-      private val createOrOverwriteFile =
-        Files[F]
-          .writeAll(configPath, List(StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING))
+      private val createOrOverwriteFile: Pipe[F, Byte, Nothing] = bytes =>
+        fs2.Stream.exec(Files[F].createDirectories(configPath.getParent).void) ++
+          bytes.through(Files[F].writeAll(configPath, List(StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING)))
 
       def saveConfig(config: Config): F[Unit] =
         fs2

src/main/scala/com/kubukoz/next/Program.scala

@@ -1,6 +1,7 @@
 package com.kubukoz.next
 
 import cats.effect.Concurrent
+import cats.effect.Sync
 import cats.effect.MonadCancelThrow
 import cats.effect.Resource
 import cats.effect.kernel.Async
@@ -20,15 +21,44 @@ import org.http4s.client.middleware.RequestLogger
 import org.http4s.client.middleware.ResponseLogger
 import java.lang.System
 import java.nio.file.Paths
+import java.nio.file.Path
+import cats.data.OptionT
+import cats.MonadThrow
 
 object Program {
-  val configPath = Paths.get(System.getProperty("user.home")).resolve(".spotify-next.json")
 
-  def makeLoader[F[_]: Files: Ref.Make: UserOutput: Console: fs2.Compiler.Target]: F[ConfigLoader[F]] =
-    ConfigLoader
-      .cached[F]
-      .compose(ConfigLoader.withCreateFileIfMissing[F](configPath))
-      .apply(ConfigLoader.default[F](configPath))
+  trait System[F[_]] {
+    def getenv(name: String): F[Option[String]]
+  }
+
+  object System {
+    def apply[F[_]](using F: System[F]): System[F] = F
+
+    given [F[_]: Sync]: System[F] = name => Sync[F].delay(java.lang.System.getenv(name)).map(Option(_))
+  }
+
+  private def configPath[F[_]: System: MonadThrow]: F[Path] =
+    OptionT(System[F].getenv("XDG_CONFIG_HOME"))
+      .map(Paths.get(_))
+      .getOrElseF(
+        System[F]
+          .getenv("HOME")
+          .flatMap(_.liftTo[F](new Throwable("HOME not defined, I don't even")))
+          .map(Paths.get(_))
+          .map(_.resolve(".config"))
+      )
+      .map(
+        _.resolve("spotify-next")
+          .resolve("config.json")
+      )
+
+  def makeLoader[F[_]: Files: System: Ref.Make: UserOutput: Console: fs2.Compiler.Target]: F[ConfigLoader[F]] =
+    configPath[F].flatMap { p =>
+      ConfigLoader
+        .cached[F]
+        .compose(ConfigLoader.withCreateFileIfMissing[F](p))
+        .apply(ConfigLoader.default[F](p))
+    }
 
   def makeBasicClient[F[_]: Async]: Resource[F, Client[F]] =
     Resource