package akka

import sbt._
import sbt.Keys._
import java.io.File

object Rstdoc {
  val rstdocDirectory = SettingKey[File]("rstdoc-directory")
  val rstdocTarget = SettingKey[File]("rstdoc-target")
  val rstdoc = TaskKey[File]("rstdoc", "Build the reStructuredText documentation.")

  lazy val settings = Seq(
    rstdocDirectory <<= baseDirectory / "akka-docs",
    rstdocTarget <<= crossTarget / "rstdoc",
    rstdoc <<= rstdocTask
  )

  def rstdocTask = (cacheDirectory, rstdocDirectory, rstdocTarget, streams) map {
    (cacheDir, dir, target, s) => {
      val cache = cacheDir / "rstdoc"
      val cached = FileFunction.cached(cache)(FilesInfo.hash, FilesInfo.exists) { (in, out) =>
        val changes = in.modified
        if (!changes.isEmpty) {
          s.log.info("Building reStructuredText documentation...")
          changes.foreach(file => s.log.debug("Changed documentation source: " + file))
          val logger = new ProcessLogger {
            def info(o: => String): Unit = s.log.debug(o)
            def error(e: => String): Unit = s.log.debug(e)
            def buffer[T](f: => T): T = f
          }
          val exitCode = Process(List("make", "clean", "html", "pdf"), dir) ! logger
          if (exitCode != 0) sys.error("Failed to build docs.")
          s.log.info("Creating reStructuredText documentation successful.")
          IO.copyDirectory(dir / "_build" / "html", target)
          IO.copyFile(dir / "_build" / "latex" / "Akka.pdf", target / "Akka.pdf")
          target.descendentsExcept("*", "").get.toSet
        } else Set.empty
      }
      val toplevel = dir * ("*" - ".*" - "_sphinx" - "_build" - "disabled" - "target")
      val inputs = toplevel.descendentsExcept("*", "").get.toSet
      cached(inputs)
      target
    }
  }
}