/*  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])]

  case class Session_Info(

    dir: Path,

    name: String,

    parent: String,

    description: String,

    options: Options,

    theories: List[(Options, String)],

    files: List[String])

  private val pure_info =

    Session_Info(Path.current, "Pure", "", "", Nil, List((Nil, "Pure")), Nil)

  /* parsing */

  val ROOT_NAME = "ROOT"

  private case class Session_Entry(

    name: String,

    reset: Boolean,

    path: Option[String],

    parent: 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)) ~

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

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

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

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

        rep1(theories) ~

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

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

    }

    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]): List[Session_Info] =

  {

    val infos = new mutable.ListBuffer[Session_Info]

    infos += pure_info

    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 {

        val parent =

          infos.find(_.name == entry.parent) getOrElse

           error("Unknown parent session: " + quote(entry.parent))

        val full_name =

          if (entry.reset) entry.name

          else parent.name + "-" + entry.name

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

        if (infos.exists(_.name == full_name))

          error("Duplicate session name: " + quote(full_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, full_name, entry.parent, entry.description,

            entry.options, thys, entry.files)

        infos += info

      }

      catch {

        case ERROR(msg) =>

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

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

      }

    }

    infos.toList

  }

  /** 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)

    find_sessions(more_dirs) foreach println

    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))

      }

    }

  }

}