/*  Title:      Pure/System/build.scala

    Author:     Makarius

Build and manage Isabelle sessions.

*/

package isabelle

import java.io.File

import scala.collection.mutable

import scala.annotation.tailrec

object Build

{

  /** session information **/

  type Options = List[(String, Option[String])]

  object Session

  {

    object Key

    {

      object Ordering extends scala.math.Ordering[Key]

      {

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

          key2.order compare key1.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

    }

    sealed case class Info(

      dir: Path,

      key: Key,

      parent: Option[String],

      description: String,

      options: Options,

      theories: List[(Options, String)],

      files: List[String])

    {

      def name: String = key.name

    }

    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 lookup(name: String): Option[Info] =

        keys.get(name).map(graph.get_node(_))

      def + (info: Info): Queue =

      {

        val keys1 =

          if (keys.isDefinedAt(info.name)) error("Duplicate session: " + quote(info.name))

          else keys + (info.name -> info.key)

        val graph1 =

          try {

            graph.new_node(info.key, info).

              add_deps_acyclic(info.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 topological_order: List[Info] =

        graph.topological_order.map(graph.get_node(_))

    }

  }

  /* parsing */

  val ROOT_NAME = "ROOT"

  private case class Session_Entry(

    name: String,

    reset: Boolean,

    order: Int,

    path: Option[String],

    parent: Option[String],

    description: String,

    options: Options,

    theories: List[(Options, 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: File): List[Session_Entry] =

    {

      val toks = syntax.scan(Standard_System.read_file(root))

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

        case Success(result, _) => result

        case bad => error(bad.toString)

      }

    }

  }

  /* find sessions */

  def find_sessions(more_dirs: List[Path]): Session.Queue =

  {

    var sessions = Session.Queue.empty

    for {

      (dir, strict) <- Isabelle_System.components().map((_, false)) ++ more_dirs.map((_, true))

      root = Isabelle_System.platform_file(dir + Path.basic(ROOT_NAME))

      _ = (strict && !root.isFile && error("Bad session root file: " + quote(root.toString)))

      if root.isFile

      entry <- Parser.parse_entries(root)

    }

    {

      try {

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

        val full_name =

          if (entry.name == "RAW" || entry.name == "Pure") {

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

            else entry.name

          }

          else

            entry.parent match {

              case None => error("Missing parent session")

              case Some(parent) =>

                val parent_info =

                  sessions.lookup(parent) getOrElse

                    error("Undefined parent session: " + quote(parent))

                if (entry.reset) entry.name

                else parent_info.name + "-" + entry.name

            }

        val path =

          entry.path match {

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

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

          }

        val thys = entry.theories.map({ case (x, ys) => ys.map(y => (x, y)) }).flatten

        val info =

          Session.Info(dir + path, Session.Key(full_name, entry.order),

            entry.parent, entry.description, entry.options, thys, entry.files)

        sessions += info

      }

      catch {

        case ERROR(msg) =>

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

            quote(entry.name) + " (file " + quote(root.toString) + ")")

      }

    }

    sessions

  }

  /** build **/

  def build(all_sessions: Boolean, build_images: Boolean, list_only: Boolean,

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

  {

    println("more_dirs = " + more_dirs.toString)

    println("options = " + options.toString)

    println("sessions = " + sessions.toString)

    for (info <- find_sessions(more_dirs).topological_order)

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

    0

  }

  /* 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.Boolean(list_only) ::

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

            build(all_sessions, build_images, list_only,

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

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

      }

    }

  }

}