/*  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 =

          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

    }

    sealed case class Info(

      dir: Path,

      description: String,

      options: Options,

      theories: List[(Options, String)],

      files: List[String])

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

      def + (key: Key, info: Info, parent: Option[String]): 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, 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[(Key, Info)] =

        graph.topological_order.map(key => (key, 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: 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 */

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

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

  private def sessions_root(dir: Path, root: File, queue: Session.Queue): Session.Queue =

  {

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

      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 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 info = Session.Info(dir + path, entry.description, entry.options,

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

        queue1 + (key, info, entry.parent)

      }

      catch {

        case ERROR(msg) =>

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

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

      })

  }

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

  {

    val root = Isabelle_System.platform_file(dir + ROOT)

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

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

    else queue

  }

  private def sessions_catalog(dir: Path, catalog: File, queue: Session.Queue): Session.Queue =

  {

    val dirs =

      split_lines(Standard_System.read_file(catalog)).

        filterNot(line => line == "" || line.startsWith("#"))

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

      try {

        val dir2 = dir + Path.explode(dir1)

        if (Isabelle_System.platform_file(dir2).isDirectory) sessions_dir(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(more_dirs: List[Path]): Session.Queue =

  {

    var queue = Session.Queue.empty

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

      queue = sessions_dir(false, dir, queue)

      val catalog = Isabelle_System.platform_file(dir + SESSIONS)

      if (catalog.isFile)

        queue = sessions_catalog(dir, catalog, queue)

    }

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

    queue

  }

  /** 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 ((key, info) <- find_sessions(more_dirs).topological_order)

      println(key.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))

      }

    }

  }

}