/*  Title:      Pure/System/build.scala

    Author:     Makarius

Build and manage Isabelle sessions.

*/

package isabelle

import java.io.{File => JFile}

import scala.collection.mutable

import scala.annotation.tailrec

object Build

{

  /** session information **/

  object Session

  {

    /* Key */

    object Key

    {

      object Ordering extends scala.math.Ordering[Key]

      {

        def compare(key1: Key, key2: Key): Int =

          key1.order compare key2.order match {

            case 0 => key1.name compare key2.name

            case ord => ord

          }

      }

    }

    sealed case class Key(name: String, order: Int)

    {

      override def toString: String = name

    }

    /* Info */

    sealed case class Info(

      dir: Path,

      parent: Option[String],

      description: String,

      options: Options,

      theories: List[(Options, List[Path])],

      files: List[Path],

      digest: SHA1.Digest)

    /* Queue */

    object Queue

    {

      val empty: Queue = new Queue()

    }

    final class Queue private(

      keys: Map[String, Key] = Map.empty,

      graph: Graph[Key, Info] = Graph.empty(Key.Ordering))

    {

      def is_empty: Boolean = graph.is_empty

      def apply(name: String): Info = graph.get_node(keys(name))

      def defined(name: String): Boolean = keys.isDefinedAt(name)

      def is_inner(name: String): Boolean = !graph.is_maximal(keys(name))

      def + (key: Key, info: Info): Queue =

      {

        val keys1 =

          if (defined(key.name)) error("Duplicate session: " + quote(key.name))

          else keys + (key.name -> key)

        val graph1 =

          try {

            graph.new_node(key, info).add_deps_acyclic(key, info.parent.toList.map(keys(_)))

          }

          catch {

            case exn: Graph.Cycles[_] =>

              error(cat_lines(exn.cycles.map(cycle =>

                "Cyclic session dependency of " +

                  cycle.map(key => quote(key.toString)).mkString(" via "))))

          }

        new Queue(keys1, graph1)

      }

      def - (name: String): Queue = new Queue(keys - name, graph.del_node(keys(name)))

      def required(names: List[String]): Queue =

      {

        val req = graph.all_preds(names.map(keys(_))).map(_.name).toSet

        val keys1 = keys -- keys.keySet.filter(name => !req(name))

        val graph1 = graph.restrict(key => keys1.isDefinedAt(key.name))

        new Queue(keys1, graph1)

      }

      def dequeue(skip: String => Boolean): Option[(String, Info)] =

      {

        val it = graph.entries.dropWhile(

          { case (key, (_, (deps, _))) => !deps.isEmpty || skip(key.name) })

        if (it.hasNext) { val (key, (info, _)) = it.next; Some((key.name, info)) }

        else None

      }

      def topological_order: List[(String, Info)] =

        graph.topological_order.map(key => (key.name, graph.get_node(key)))

    }

  }

  /* parsing */

  private case class Session_Entry(

    name: String,

    reset: Boolean,

    order: Int,

    path: Option[String],

    parent: Option[String],

    description: String,

    options: List[Options.Spec],

    theories: List[(List[Options.Spec], List[String])],

    files: List[String])

  private object Parser extends Parse.Parser

  {

    val SESSION = "session"

    val IN = "in"

    val DESCRIPTION = "description"

    val OPTIONS = "options"

    val THEORIES = "theories"

    val FILES = "files"

    val syntax =

      Outer_Syntax.empty + "!" + "(" + ")" + "+" + "," + "=" + "[" + "]" +

        SESSION + IN + DESCRIPTION + OPTIONS + THEORIES + FILES

    val session_entry: Parser[Session_Entry] =

    {

      val session_name = atom("session name", _.is_name)

      val theory_name = atom("theory name", _.is_name)

      val option =

        name ~ opt(keyword("=") ~! name ^^ { case _ ~ x => x }) ^^ { case x ~ y => (x, y) }

      val options = keyword("[") ~> repsep(option, keyword(",")) <~ keyword("]")

      val theories =

        keyword(THEORIES) ~! ((options | success(Nil)) ~ rep1(theory_name)) ^^

          { case _ ~ (x ~ y) => (x, y) }

      ((keyword(SESSION) ~! session_name) ^^ { case _ ~ x => x }) ~

        (keyword("!") ^^^ true | success(false)) ~

        (keyword("(") ~! (nat <~ keyword(")")) ^^ { case _ ~ x => x } | success(Integer.MAX_VALUE)) ~

        (opt(keyword(IN) ~! string ^^ { case _ ~ x => x })) ~

        (keyword("=") ~> opt(session_name <~ keyword("+"))) ~

        (keyword(DESCRIPTION) ~! text ^^ { case _ ~ x => x } | success("")) ~

        (keyword(OPTIONS) ~! options ^^ { case _ ~ x => x } | success(Nil)) ~

        rep(theories) ~

        (keyword(FILES) ~! rep1(path) ^^ { case _ ~ x => x } | success(Nil)) ^^

          { case a ~ b ~ c ~ d ~ e ~ f ~ g ~ h ~ i => Session_Entry(a, b, c, d, e, f, g, h, i) }

    }

    def parse_entries(root: JFile): List[Session_Entry] =

    {

      val toks = syntax.scan(File.read(root))

      parse_all(rep(session_entry), Token.reader(toks, root.toString)) match {

        case Success(result, _) => result

        case bad => error(bad.toString)

      }

    }

  }

  /* find sessions */

  private val ROOT = Path.explode("ROOT")

  private val SESSIONS = Path.explode("etc/sessions")

  private def is_pure(name: String): Boolean = name == "RAW" || name == "Pure"

  private def sessions_root(options: Options, dir: Path, root: JFile, queue: Session.Queue)

    : Session.Queue =

  {

    (queue /: Parser.parse_entries(root))((queue1, entry) =>

      try {

        if (entry.name == "") error("Bad session name")

        val full_name =

          if (is_pure(entry.name)) {

            if (entry.parent.isDefined) error("Illegal parent session")

            else entry.name

          }

          else

            entry.parent match {

              case Some(parent_name) if queue1.defined(parent_name) =>

                if (entry.reset) entry.name

                else parent_name + "-" + entry.name

              case _ => error("Bad parent session")

            }

        val path =

          entry.path match {

            case Some(p) => Path.explode(p)

            case None => Path.basic(entry.name)

          }

        val key = Session.Key(full_name, entry.order)

        val theories =

          entry.theories.map({ case (opts, thys) => (options ++ opts, thys.map(Path.explode(_))) })

        val files = entry.files.map(Path.explode(_))

        val digest = SHA1.digest((full_name, entry.parent, entry.options, entry.theories).toString)

        val info =

          Session.Info(dir + path, entry.parent,

            entry.description, options ++ entry.options, theories, files, digest)

        queue1 + (key, info)

      }

      catch {

        case ERROR(msg) =>

          error(msg + "\nThe error(s) above occurred in session entry " +

            quote(entry.name) + Position.str_of(Position.file(root)))

      })

  }

  private def sessions_dir(options: Options, strict: Boolean, dir: Path, queue: Session.Queue)

    : Session.Queue =

  {

    val root = (dir + ROOT).file

    if (root.isFile) sessions_root(options, dir, root, queue)

    else if (strict) error("Bad session root file: " + quote(root.toString))

    else queue

  }

  private def sessions_catalog(options: Options, dir: Path, catalog: JFile, queue: Session.Queue)

    : Session.Queue =

  {

    val dirs =

      split_lines(File.read(catalog)).filterNot(line => line == "" || line.startsWith("#"))

    (queue /: dirs)((queue1, dir1) =>

      try {

        val dir2 = dir + Path.explode(dir1)

        if (dir2.file.isDirectory) sessions_dir(options, true, dir2, queue1)

        else error("Bad session directory: " + dir2.toString)

      }

      catch {

        case ERROR(msg) =>

          error(msg + "\nThe error(s) above occurred in session catalog " + quote(catalog.toString))

      })

  }

  def find_sessions(options: Options, all_sessions: Boolean, sessions: List[String],

    more_dirs: List[Path]): Session.Queue =

  {

    var queue = Session.Queue.empty

    for (dir <- Isabelle_System.components()) {

      queue = sessions_dir(options, false, dir, queue)

      val catalog = (dir + SESSIONS).file

      if (catalog.isFile)

        queue = sessions_catalog(options, dir, catalog, queue)

    }

    for (dir <- more_dirs) queue = sessions_dir(options, true, dir, queue)

    sessions.filter(name => !queue.defined(name)) match {

      case Nil =>

      case bad => error("Undefined session(s): " + commas_quote(bad))

    }

    if (all_sessions) queue else queue.required(sessions)

  }

  /** build **/

  /* dependencies */

  sealed case class Node(

    loaded_theories: Set[String],

    sources: List[(Path, SHA1.Digest)])

  sealed case class Deps(deps: Map[String, Node])

  {

    def sources(name: String): List[(Path, SHA1.Digest)] = deps(name).sources

  }

  def dependencies(queue: Session.Queue): Deps =

    Deps((Map.empty[String, Node] /: queue.topological_order)(

      { case (deps, (name, info)) =>

          val preloaded =

            info.parent match {

              case None => Set.empty[String]

              case Some(parent) => deps(parent).loaded_theories

            }

          val thy_info = new Thy_Info(new Thy_Load(preloaded))

          val thy_deps =

            thy_info.dependencies(

              info.theories.map(_._2).flatten.

                map(thy => Document.Node.Name(info.dir + Thy_Load.thy_path(thy))))

          val loaded_theories = preloaded ++ thy_deps.map(_._1.theory)

          val all_files =

            thy_deps.map({ case (n, h) =>

              val thy = Path.explode(n.node).expand

              val uses =

                h match {

                  case Exn.Res(d) =>

                    d.uses.map(p => (Path.explode(n.dir) + Path.explode(p._1)).expand)

                  case _ => Nil

                }

              thy :: uses

            }).flatten ::: info.files.map(file => info.dir + file)

          val sources = all_files.par.map(p => (p, SHA1.digest(p))).toList

          deps + (name -> Node(loaded_theories, sources))

      }))

  /* jobs */

  private class Job(cwd: JFile, env: Map[String, String], script: String, args: String)

  {

    private val args_file = File.tmp_file("args")

    private val env1 = env + ("ARGS_FILE" -> Isabelle_System.posix_path(args_file.getPath))

    File.write(args_file, args)

    private val (thread, result) =

      Simple_Thread.future("build") { Isabelle_System.bash_env(cwd, env1, script) }

    def terminate: Unit = thread.interrupt

    def is_finished: Boolean = result.is_finished

    def join: (String, String, Int) = { val res = result.join; args_file.delete; res }

  }

  private def start_job(save: Boolean, name: String, info: Session.Info): Job =

  {

    val parent = info.parent.getOrElse("")

    val cwd = info.dir.file

    val env = Map("INPUT" -> parent, "TARGET" -> name)

    val script =

      if (is_pure(name)) "./build " + (if (save) "-b " else "") + name

      else {

        """

        . "$ISABELLE_HOME/lib/scripts/timestart.bash"

        """ +

          (if (save)

            """ "$ISABELLE_PROCESS" -e "Build.build \"$ARGS_FILE\";" -q -w "$INPUT" "$TARGET" """

          else

            """ "$ISABELLE_PROCESS" -e "Build.build \"$ARGS_FILE\";" -r -q "$INPUT" """) +

        """

        RC="$?"

        . "$ISABELLE_HOME/lib/scripts/timestop.bash"

        if [ "$RC" -eq 0 ]; then

          echo "Finished $TARGET ($TIMES_REPORT)" >&2

        fi

        exit "$RC"

        """

      }

    val args_xml =

    {

      import XML.Encode._

      pair(bool, pair(string, pair(string, list(string))))(

        save, (parent, (name, info.theories.map(_._2).flatten.map(_.implode))))

    }

    new Job(cwd, env, script, YXML.string_of_body(args_xml))

  }

  /* build */

  private def echo(msg: String) { java.lang.System.out.println(msg) }

  private def sleep(): Unit = Thread.sleep(500)

  def build(all_sessions: Boolean, build_images: Boolean, max_jobs: Int,

    list_only: Boolean, verbose: Boolean,

    more_dirs: List[Path], more_options: List[String], sessions: List[String]): Int =

  {

    val options = (Options.init() /: more_options)(_.define_simple(_))

    val queue = find_sessions(options, all_sessions, sessions, more_dirs)

    val deps = dependencies(queue)

    // prepare browser info dir

    if (options.bool("browser_info") &&

      !Path.explode("$ISABELLE_BROWSER_INFO/index.html").file.isFile)

    {

      Path.explode("$ISABELLE_BROWSER_INFO").file.mkdirs()

      File.copy(Path.explode("$ISABELLE_HOME/lib/logo/isabelle.gif"),

        Path.explode("$ISABELLE_BROWSER_INFO/isabelle.gif"))

      File.write(Path.explode("$ISABELLE_BROWSER_INFO/index.html"),

        File.read(Path.explode("$ISABELLE_HOME/lib/html/library_index_header.template")) +

        File.read(Path.explode("$ISABELLE_HOME/lib/html/library_index_content.template")) +

        File.read(Path.explode("$ISABELLE_HOME/lib/html/library_index_footer.template")))

    }

    // prepare log dir

    val log_dir = Path.explode("$ISABELLE_OUTPUT/log")

    log_dir.file.mkdirs()

    // scheduler loop

    @tailrec def loop(

      pending: Session.Queue,

      running: Map[String, Job],

      results: Map[String, Int]): Map[String, Int] =

    {

      if (pending.is_empty) results

      else if (running.exists({ case (_, job) => job.is_finished })) {

        val (name, job) = running.find({ case (_, job) => job.is_finished }).get

        val (out, err, rc) = job.join

        echo(Library.trim_line(err))

        val log = log_dir + Path.basic(name)

        if (rc == 0) {

          val sources =

            (queue(name).digest :: deps.sources(name).map(_._2)).map(_.toString).sorted

              .mkString("sources: ", " ", "\n")

          File.write_zip(log.ext("gz"), sources + out)

        }

        else {

          File.write(log, out)

          echo(name + " FAILED")

          echo("(see also " + log.file + ")")

          val lines = split_lines(out)

          val tail = lines.drop(lines.length - 20 max 0)

          echo("\n" + cat_lines(tail))

        }

        loop(pending - name, running - name, results + (name -> rc))

      }

      else if (running.size < (max_jobs max 1)) {

        pending.dequeue(running.isDefinedAt(_)) match {

          case Some((name, info)) =>

            if (list_only) {

              echo(name + " in " + info.dir)

              loop(pending - name, running, results + (name -> 0))

            }

            else if (info.parent.map(results(_)).forall(_ == 0)) {

              val save = build_images || queue.is_inner(name)

              echo((if (save) "Building " else "Running ") + name + " ...")

              val job = start_job(save, name, info)

              loop(pending, running + (name -> job), results)

            }

            else {

              echo(name + " CANCELLED")

              loop(pending - name, running, results + (name -> 1))

            }

          case None => sleep(); loop(pending, running, results)

        }

      }

      else { sleep(); loop(pending, running, results) }

    }

    (0 /: loop(queue, Map.empty, Map.empty))({ case (rc1, (_, rc2)) => rc1 max rc2 })

  }

  /* command line entry point */

  def main(args: Array[String])

  {

    Command_Line.tool {

      args.toList match {

        case

          Properties.Value.Boolean(all_sessions) ::

          Properties.Value.Boolean(build_images) ::

          Properties.Value.Int(max_jobs) ::

          Properties.Value.Boolean(list_only) ::

          Properties.Value.Boolean(verbose) ::

          Command_Line.Chunks(more_dirs, options, sessions) =>

            build(all_sessions, build_images, max_jobs, list_only, verbose,

              more_dirs.map(Path.explode), options, sessions)

        case _ => error("Bad arguments:\n" + cat_lines(args))

      }

    }

  }

}