Move comment handling into generator

modules/core/src/main/scala/io/taig/blowout/BlowoutGenerator.scala

@@ -2,10 +2,16 @@ package io.taig.blowout
 
 import sbt.File
 
-final case class BlowoutGenerator(target: File, content: () => String)
+final case class BlowoutGenerator(
+    target: File,
+    content: () => String,
+    comment: BlowoutComment = BlowoutComment.Disabled
+)
 
 object BlowoutGenerator {
-  def lzy(target: File, content: => String): BlowoutGenerator = BlowoutGenerator(target, () => content)
+  def lzy(target: File, content: => String, comment: BlowoutComment = BlowoutComment.Disabled): BlowoutGenerator =
+    BlowoutGenerator(target, () => content, comment)
 
-  def strict(target: File, content: String): BlowoutGenerator = BlowoutGenerator(target, () => content)
+  def strict(target: File, content: String, comment: BlowoutComment = BlowoutComment.Disabled): BlowoutGenerator =
+    BlowoutGenerator(target, () => content, comment)
 }

modules/core/src/main/scala/io/taig/blowout/BlowoutKeys.scala

@@ -3,9 +3,7 @@ package io.taig.blowout
 import sbt._
 
 trait BlowoutKeys {
-  lazy val blowoutHeader = settingKey[File => Option[String]](
-    "Optional comment header that is added to installed files, depending on their file extension"
-  )
+  lazy val blowoutHeader = settingKey[List[String]]("Optional comment header that is added to installed files")
 
   lazy val blowoutGenerators = settingKey[List[BlowoutGenerator]](
     "Generators that describe where files should be installed to by blowoutGenerate and what content they should have"

modules/core/src/main/scala/io/taig/blowout/BlowoutPlugin.scala

@@ -11,6 +11,9 @@ object BlowoutPlugin extends AutoPlugin {
   object autoImport extends BlowoutKeys {
     type BlowoutGenerator = io.taig.blowout.BlowoutGenerator
     val BlowoutGenerator = io.taig.blowout.BlowoutGenerator
+
+    type BlowoutComment = io.taig.blowout.BlowoutComment
+    val BlowoutComment = io.taig.blowout.BlowoutComment
   }
 
   import autoImport._
@@ -21,18 +24,12 @@ object BlowoutPlugin extends AutoPlugin {
 
   override def projectSettings: Seq[Def.Setting[_]] = Def.settings(
     blowoutGenerators := Nil,
-    blowoutHeader := { file =>
-      val message = List(
-        "This file was automatically generated by sbt-blowout and should not be edited manually.",
-        "Instead, run blowoutGenerate after making the desired changes to your build definition."
-      )
-
-      PartialFunction.condOpt((file.name, file.ext)) { case ("Dockerfile", "") | (_, "conf" | "yml" | "yaml") =>
-        message.map("# " + _).mkString("\n")
-      }
-    },
+    blowoutHeader := List(
+      "This file was automatically generated by sbt-blowout and should not be edited manually.",
+      "Instead, run blowoutGenerate after making the desired changes to your build definition."
+    ),
     blowoutRender := { generator =>
-      blowoutHeader.value(generator.target).map(_ + "\n").getOrElse("") + generator.content()
+      Some(blowoutHeader.value).filter(_.nonEmpty).flatMap(generator.comment).getOrElse("") + generator.content()
     },
     blowoutGenerate := {
       blowoutGenerators.value.map { generator =>

modules/core/src/main/scala/io/taig/blowout/package.scala

@@ -0,0 +1,15 @@
+package io.taig
+
+package object blowout {
+  type BlowoutComment = List[String] => Option[String]
+
+  object BlowoutComment {
+    val Disabled: BlowoutComment = _ => None
+
+    def prefixed(prefix: String): BlowoutComment = lines =>
+      Some(lines.map(line => s"$prefix$line").mkString("", "\n", "\n"))
+
+    val Hash: BlowoutComment = prefixed("# ")
+    val Slash: BlowoutComment = prefixed("// ")
+  }
+}

modules/json-circe/src/main/scala/io/taig/blowout/BlowoutJsonGenerator.scala

@@ -6,11 +6,11 @@ import sbt.File
 
 object BlowoutJsonGenerator {
   def apply(target: File, content: () => Json, printer: Printer = Printer.spaces2): BlowoutGenerator =
-    BlowoutGenerator(target, () => printer.print(content()))
+    BlowoutGenerator(target, () => printer.print(content()), comment = BlowoutComment.Disabled)
 
   def lzy(target: File, content: => Json, printer: Printer = Printer.spaces2): BlowoutGenerator =
-    BlowoutGenerator(target, () => printer.print(content))
+    BlowoutGenerator(target, () => printer.print(content), comment = BlowoutComment.Disabled)
 
   def strict(target: File, content: Json, printer: Printer = Printer.spaces2): BlowoutGenerator =
-    BlowoutJsonGenerator(target, () => content, printer)
+    BlowoutGenerator.strict(target, printer.print(content), comment = BlowoutComment.Disabled)
 }

modules/yaml-circe/src/main/scala/io/taig/blowout/BlowoutYamlGenerator.scala

@@ -7,12 +7,24 @@ import sbt.File
 object BlowoutYamlGenerator {
   val DefaultPrinter: Printer = Printer.spaces2.copy(preserveOrder = true, splitLines = false)
 
-  def apply(target: File, content: () => Json, printer: Printer = DefaultPrinter): BlowoutGenerator =
-    BlowoutGenerator(target, () => printer.pretty(content()))
+  def apply(
+      target: File,
+      content: () => Json,
+      printer: Printer = DefaultPrinter,
+      comment: BlowoutComment = BlowoutComment.Hash
+  ): BlowoutGenerator = BlowoutGenerator(target, () => printer.pretty(content()), comment)
 
-  def lzy(target: File, content: => Json, printer: Printer = DefaultPrinter): BlowoutGenerator =
-    BlowoutGenerator(target, () => printer.pretty(content))
+  def lzy(
+      target: File,
+      content: => Json,
+      printer: Printer = DefaultPrinter,
+      comment: BlowoutComment = BlowoutComment.Hash
+  ): BlowoutGenerator = BlowoutGenerator(target, () => printer.pretty(content), comment)
 
-  def strict(target: File, content: Json, printer: Printer = DefaultPrinter): BlowoutGenerator =
-    BlowoutYamlGenerator(target, () => content, printer)
+  def strict(
+      target: File,
+      content: Json,
+      printer: Printer = DefaultPrinter,
+      comment: BlowoutComment = BlowoutComment.Hash
+  ): BlowoutGenerator = BlowoutGenerator.strict(target, printer.pretty(content), comment)
 }