/*  Title:      Pure/Thy/sessions.scala

    Author:     Makarius

Isabelle session information.

*/

package isabelle

import java.nio.ByteBuffer

import java.nio.channels.FileChannel

import java.nio.file.StandardOpenOption

import java.sql.PreparedStatement

import scala.collection.SortedSet

import scala.collection.mutable

object Sessions

{

  /* base info and source dependencies */

  def is_pure(name: String): Boolean = name == Thy_Header.PURE

  object Base

  {

    def pure(options: Options): Base = session_base(options, Thy_Header.PURE)

    lazy val bootstrap: Base =

      Base(keywords = Thy_Header.bootstrap_header, syntax = Thy_Header.bootstrap_syntax)

  }

  sealed case class Base(

    loaded_theories: Set[String] = Set.empty,

    known_theories: Map[String, Document.Node.Name] = Map.empty,

    keywords: Thy_Header.Keywords = Nil,

    syntax: Outer_Syntax = Outer_Syntax.empty,

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

    session_graph: Graph_Display.Graph = Graph_Display.empty_graph)

  {

    def loaded_theory(name: Document.Node.Name): Boolean =

      loaded_theories.contains(name.theory)

  }

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

  {

    def is_empty: Boolean = deps.isEmpty

    def apply(name: String): Base = deps(name)

    def sources(name: String): List[SHA1.Digest] = deps(name).sources.map(_._2)

  }

  def dependencies(

      progress: Progress = No_Progress,

      inlined_files: Boolean = false,

      verbose: Boolean = false,

      list_files: Boolean = false,

      check_keywords: Set[String] = Set.empty,

      tree: Tree): Deps =

    Deps((Map.empty[String, Base] /: tree.topological_order)(

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

          if (progress.stopped) throw Exn.Interrupt()

          try {

            val parent_base =

              info.parent match {

                case None => Base.bootstrap

                case Some(parent) => deps(parent)

              }

            val resources = new Resources(name, parent_base)

            if (verbose || list_files) {

              val groups =

                if (info.groups.isEmpty) ""

                else info.groups.mkString(" (", " ", ")")

              progress.echo("Session " + info.chapter + "/" + name + groups)

            }

            val thy_deps =

            {

              val root_theories =

                info.theories.flatMap({

                  case (global, _, thys) =>

                    thys.map(thy =>

                      (resources.init_name(global, info.dir + resources.thy_path(thy)), info.pos))

                })

              val thy_deps = resources.thy_info.dependencies(root_theories)

              thy_deps.errors match {

                case Nil => thy_deps

                case errs => error(cat_lines(errs))

              }

            }

            val known_theories =

              (parent_base.known_theories /: thy_deps.deps)({ case (known, dep) =>

                val name = dep.name

                known.get(name.theory) match {

                  case Some(name1) if name != name1 =>

                    error("Duplicate theory " + quote(name.node) + " vs. " + quote(name1.node))

                  case _ =>

                    known + (name.theory -> name) + (Long_Name.base_name(name.theory) -> name)

                }

              })

            val loaded_theories = thy_deps.loaded_theories

            val keywords = thy_deps.keywords

            val syntax = thy_deps.syntax

            val theory_files = thy_deps.deps.map(dep => Path.explode(dep.name.node))

            val loaded_files =

              if (inlined_files) {

                val pure_files =

                  if (is_pure(name)) {

                    val roots = Thy_Header.ml_roots.map(p => info.dir + Path.explode(p._1))

                    val files =

                      roots.flatMap(root => resources.loaded_files(syntax, File.read(root))).

                        map(file => info.dir + Path.explode(file))

                    roots ::: files

                  }

                  else Nil

                pure_files ::: thy_deps.loaded_files

              }

              else Nil

            val all_files =

              (theory_files ::: loaded_files :::

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

                info.document_files.map(file => info.dir + file._1 + file._2)).map(_.expand)

            if (list_files)

              progress.echo(cat_lines(all_files.map(_.implode).sorted.map("  " + _)))

            if (check_keywords.nonEmpty)

              Check_Keywords.check_keywords(progress, syntax.keywords, check_keywords, theory_files)

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

            val session_graph =

              Present.session_graph(info.parent getOrElse "",

                parent_base.loaded_theories, thy_deps.deps)

            val base =

              Base(loaded_theories, known_theories, keywords, syntax, sources, session_graph)

            deps + (name -> base)

          }

          catch {

            case ERROR(msg) =>

              cat_error(msg, "The error(s) above occurred in session " +

                quote(name) + Position.here(info.pos))

          }

      }))

  def session_base(options: Options, session: String, dirs: List[Path] = Nil): Base =

  {

    val (_, tree) = load(options, dirs = dirs).selection(sessions = List(session))

    dependencies(tree = tree)(session)

  }

  /* session tree */

  sealed case class Info(

    chapter: String,

    select: Boolean,

    pos: Position.T,

    groups: List[String],

    dir: Path,

    parent: Option[String],

    description: String,

    options: Options,

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

    files: List[Path],

    document_files: List[(Path, Path)],

    meta_digest: SHA1.Digest)

  {

    def timeout: Time = Time.seconds(options.real("timeout") * options.real("timeout_scale"))

  }

  object Tree

  {

    def apply(infos: Seq[(String, Info)]): Tree =

    {

      val graph1 =

        (Graph.string[Info] /: infos) {

          case (graph, (name, info)) =>

            if (graph.defined(name))

              error("Duplicate session " + quote(name) + Position.here(info.pos) +

                Position.here(graph.get_node(name).pos))

            else graph.new_node(name, info)

        }

      val graph2 =

        (graph1 /: graph1.iterator) {

          case (graph, (name, (info, _))) =>

            info.parent match {

              case None => graph

              case Some(parent) =>

                if (!graph.defined(parent))

                  error("Bad parent session " + quote(parent) + " for " +

                    quote(name) + Position.here(info.pos))

                try { graph.add_edge_acyclic(parent, name) }

                catch {

                  case exn: Graph.Cycles[_] =>

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

                      "Cyclic session dependency of " +

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

                          Position.here(info.pos))

                }

            }

        }

      new Tree(graph2)

    }

  }

  final class Tree private(val graph: Graph[String, Info])

    extends PartialFunction[String, Info]

  {

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

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

    def selection(

      requirements: Boolean = false,

      all_sessions: Boolean = false,

      exclude_session_groups: List[String] = Nil,

      exclude_sessions: List[String] = Nil,

      session_groups: List[String] = Nil,

      sessions: List[String] = Nil): (List[String], Tree) =

    {

      val bad_sessions =

        SortedSet((exclude_sessions ::: sessions).filterNot(isDefinedAt(_)): _*).toList

      if (bad_sessions.nonEmpty) error("Undefined session(s): " + commas_quote(bad_sessions))

      val excluded =

      {

        val exclude_group = exclude_session_groups.toSet

        val exclude_group_sessions =

          (for {

            (name, (info, _)) <- graph.iterator

            if apply(name).groups.exists(exclude_group)

          } yield name).toList

        graph.all_succs(exclude_group_sessions ::: exclude_sessions).toSet

      }

      val pre_selected =

      {

        if (all_sessions) graph.keys

        else {

          val select_group = session_groups.toSet

          val select = sessions.toSet

          (for {

            (name, (info, _)) <- graph.iterator

            if info.select || select(name) || apply(name).groups.exists(select_group)

          } yield name).toList

        }

      }.filterNot(excluded)

      val selected =

        if (requirements) (graph.all_preds(pre_selected).toSet -- pre_selected).toList

        else pre_selected

      val graph1 = graph.restrict(graph.all_preds(selected).toSet)

      (selected, new Tree(graph1))

    }

    def ancestors(name: String): List[String] =

      graph.all_preds(List(name)).tail.reverse

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

      graph.topological_order.map(name => (name, apply(name)))

    override def toString: String = graph.keys_iterator.mkString("Sessions.Tree(", ", ", ")")

  }

  /* parser */

  val ROOT = Path.explode("ROOT")

  val ROOTS = Path.explode("ROOTS")

  private val CHAPTER = "chapter"

  private val SESSION = "session"

  private val IN = "in"

  private val DESCRIPTION = "description"

  private val OPTIONS = "options"

  private val GLOBAL_THEORIES = "global_theories"

  private val THEORIES = "theories"

  private val FILES = "files"

  private val DOCUMENT_FILES = "document_files"

  lazy val root_syntax =

    Outer_Syntax.init() + "(" + ")" + "+" + "," + "=" + "[" + "]" + IN +

      (CHAPTER, Keyword.THY_DECL) +

      (SESSION, Keyword.THY_DECL) +

      (DESCRIPTION, Keyword.QUASI_COMMAND) +

      (OPTIONS, Keyword.QUASI_COMMAND) +

      (GLOBAL_THEORIES, Keyword.QUASI_COMMAND) +

      (THEORIES, Keyword.QUASI_COMMAND) +

      (FILES, Keyword.QUASI_COMMAND) +

      (DOCUMENT_FILES, Keyword.QUASI_COMMAND)

  private object Parser extends Parse.Parser with Options.Parser

  {

    private abstract class Entry

    private sealed case class Chapter(name: String) extends Entry

    private sealed case class Session_Entry(

      pos: Position.T,

      name: String,

      groups: List[String],

      path: String,

      parent: Option[String],

      description: String,

      options: List[Options.Spec],

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

      files: List[String],

      document_files: List[(String, String)]) extends Entry

    private val chapter: Parser[Chapter] =

    {

      val chapter_name = atom("chapter name", _.is_name)

      command(CHAPTER) ~! chapter_name ^^ { case _ ~ a => Chapter(a) }

    }

    private val session_entry: Parser[Session_Entry] =

    {

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

      val option =

        option_name ~ opt($$$("=") ~! option_value ^^

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

      val options = $$$("[") ~> rep1sep(option, $$$(",")) <~ $$$("]")

      val theories =

        ($$$(GLOBAL_THEORIES) | $$$(THEORIES)) ~!

          ((options | success(Nil)) ~ rep(theory_name)) ^^

          { case x ~ (y ~ z) => (x == GLOBAL_THEORIES, y, z) }

      val document_files =

        $$$(DOCUMENT_FILES) ~!

          (($$$("(") ~! ($$$(IN) ~! (path ~ $$$(")"))) ^^

              { case _ ~ (_ ~ (x ~ _)) => x } | success("document")) ~

            rep1(path)) ^^ { case _ ~ (x ~ y) => y.map((x, _)) }

      command(SESSION) ~!

        (position(session_name) ~

          (($$$("(") ~! (rep1(name) <~ $$$(")")) ^^ { case _ ~ x => x }) | success(Nil)) ~

          (($$$(IN) ~! path ^^ { case _ ~ x => x }) | success(".")) ~

          ($$$("=") ~!

            (opt(session_name ~! $$$("+") ^^ { case x ~ _ => x }) ~

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

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

              rep1(theories) ~

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

              (rep(document_files) ^^ (x => x.flatten))))) ^^

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

            Session_Entry(pos, a, b, c, d, e, f, g, h, i) }

    }

    def parse(options: Options, select: Boolean, dir: Path): List[(String, Info)] =

    {

      def make_info(entry_chapter: String, entry: Session_Entry): (String, Info) =

      {

        try {

          val name = entry.name

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

          if (is_pure(name) && entry.parent.isDefined) error("Illegal parent session")

          if (!is_pure(name) && !entry.parent.isDefined) error("Missing parent session")

          val session_options = options ++ entry.options

          val theories =

            entry.theories.map({ case (global, opts, thys) =>

              (global, session_options ++ opts, thys.map(Path.explode(_))) })

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

          val document_files =

            entry.document_files.map({ case (s1, s2) => (Path.explode(s1), Path.explode(s2)) })

          val meta_digest =

            SHA1.digest((entry_chapter, name, entry.parent, entry.options,

              entry.theories, entry.files, entry.document_files).toString)

          val info =

            Info(entry_chapter, select, entry.pos, entry.groups, dir + Path.explode(entry.path),

              entry.parent, entry.description, session_options, theories, files,

              document_files, meta_digest)

          (name, info)

        }

        catch {

          case ERROR(msg) =>

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

              quote(entry.name) + Position.here(entry.pos))

        }

      }

      val root = dir + ROOT

      if (root.is_file) {

        val toks = Token.explode(root_syntax.keywords, File.read(root))

        val start = Token.Pos.file(root.implode)

        parse_all(rep(chapter | session_entry), Token.reader(toks, start)) match {

          case Success(result, _) =>

            var entry_chapter = "Unsorted"

            val infos = new mutable.ListBuffer[(String, Info)]

            result.foreach {

              case Chapter(name) => entry_chapter = name

              case entry: Session_Entry => infos += make_info(entry_chapter, entry)

            }

            infos.toList

          case bad => error(bad.toString)

        }

      }

      else Nil

    }

  }

  /* load sessions from certain directories */

  private def is_session_dir(dir: Path): Boolean =

    (dir + ROOT).is_file || (dir + ROOTS).is_file

  private def check_session_dir(dir: Path): Path =

    if (is_session_dir(dir)) dir

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

  def load(options: Options, dirs: List[Path] = Nil, select_dirs: List[Path] = Nil): Tree =

  {

    def load_dir(select: Boolean, dir: Path): List[(String, Info)] =

      load_root(select, dir) ::: load_roots(select, dir)

    def load_root(select: Boolean, dir: Path): List[(String, Info)] =

      Parser.parse(options, select, dir)

    def load_roots(select: Boolean, dir: Path): List[(String, Info)] =

    {

      val roots = dir + ROOTS

      if (roots.is_file) {

        for {

          line <- split_lines(File.read(roots))

          if !(line == "" || line.startsWith("#"))

          dir1 =

            try { check_session_dir(dir + Path.explode(line)) }

            catch {

              case ERROR(msg) =>

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

            }

          info <- load_dir(select, dir1)

        } yield info

      }

      else Nil

    }

    val default_dirs = Isabelle_System.components().filter(is_session_dir(_))

    dirs.foreach(check_session_dir(_))

    select_dirs.foreach(check_session_dir(_))

    Tree(

      for {

        (select, dir) <- (default_dirs ::: dirs).map((false, _)) ::: select_dirs.map((true, _))

        info <- load_dir(select, dir)

      } yield info)

  }

  /** heap file with SHA1 digest **/

  private val sha1_prefix = "SHA1:"

  def read_heap_digest(heap: Path): Option[String] =

  {

    if (heap.is_file) {

      val file = FileChannel.open(heap.file.toPath, StandardOpenOption.READ)

      try {

        val len = file.size

        val n = sha1_prefix.length + SHA1.digest_length

        if (len >= n) {

          file.position(len - n)

          val buf = ByteBuffer.allocate(n)

          var i = 0

          var m = 0

          do {

            m = file.read(buf)

            if (m != -1) i += m

          }

          while (m != -1 && n > i)

          if (i == n) {

            val prefix = new String(buf.array(), 0, sha1_prefix.length, UTF8.charset)

            val s = new String(buf.array(), sha1_prefix.length, SHA1.digest_length, UTF8.charset)

            if (prefix == sha1_prefix) Some(s) else None

          }

          else None

        }

        else None

      }

      finally { file.close }

    }

    else None

  }

  def write_heap_digest(heap: Path): String =

    read_heap_digest(heap) match {

      case None =>

        val s = SHA1.digest(heap).rep

        File.append(heap, sha1_prefix + s)

        s

      case Some(s) => s

    }

  /** persistent store **/

  object Session_Info

  {

    val session_name = SQL.Column.string("session_name", primary_key = true)

    // Build_Log.Session_Info

    val session_timing = SQL.Column.bytes("session_timing")

    val command_timings = SQL.Column.bytes("command_timings")

    val ml_statistics = SQL.Column.bytes("ml_statistics")

    val task_statistics = SQL.Column.bytes("task_statistics")

    val build_log_columns =

      List(session_name, session_timing, command_timings, ml_statistics, task_statistics)

    // Build.Session_Info

    val sources = SQL.Column.string("sources")

    val input_heaps = SQL.Column.string("input_heaps")

    val output_heap = SQL.Column.string("output_heap")

    val return_code = SQL.Column.int("return_code")

    val build_columns = List(sources, input_heaps, output_heap, return_code)

    val table = SQL.Table("isabelle_session_info", build_log_columns ::: build_columns)

    def where_session_name(name: String): String =

      "WHERE " + session_name.sql_name + " = " + SQL.quote_string(name)

    def select_statement(db: SQL.Database, name: String, columns: List[SQL.Column])

        : PreparedStatement =

      db.select_statement(table, columns, where_session_name(name))

    def delete_statement(db: SQL.Database, name: String): PreparedStatement =

      db.delete_statement(table, where_session_name(name))

  }

  def store(system_mode: Boolean = false): Store = new Store(system_mode)

  class Store private[Sessions](system_mode: Boolean)

  {

    /* file names */

    def database(name: String): Path = Path.basic("log") + Path.basic(name).ext("db")

    def log(name: String): Path = Path.basic("log") + Path.basic(name)

    def log_gz(name: String): Path = log(name).ext("gz")

    /* SQL database content */

    val xml_cache: XML.Cache = new XML.Cache()

    def encode_properties(ps: Properties.T): Bytes =

      Bytes(YXML.string_of_body(XML.Encode.properties(ps)))

    def decode_properties(bs: Bytes): Properties.T =

      xml_cache.props(XML.Decode.properties(YXML.parse_body(bs.text)))

    def compress_properties(ps: List[Properties.T], options: XZ.Options = XZ.options()): Bytes =

    {

      if (ps.isEmpty) Bytes.empty

      else Bytes(YXML.string_of_body(XML.Encode.list(XML.Encode.properties)(ps))).compress(options)

    }

    def uncompress_properties(bs: Bytes): List[Properties.T] =

    {

      if (bs.isEmpty) Nil

      else

        XML.Decode.list(XML.Decode.properties)(YXML.parse_body(bs.uncompress().text)).

          map(xml_cache.props(_))

    }

    def read_bytes(db: SQL.Database, name: String, column: SQL.Column): Bytes =

      using(Session_Info.select_statement(db, name, List(column)))(stmt =>

      {

        val rs = stmt.executeQuery

        if (!rs.next) Bytes.empty else db.bytes(rs, column)

      })

    def read_properties(db: SQL.Database, name: String, column: SQL.Column): List[Properties.T] =

      uncompress_properties(read_bytes(db, name, column))

    /* output */

    val browser_info: Path =

      if (system_mode) Path.explode("~~/browser_info")

      else Path.explode("$ISABELLE_BROWSER_INFO")

    val output_dir: Path =

      if (system_mode) Path.explode("~~/heaps/$ML_IDENTIFIER")

      else Path.explode("$ISABELLE_OUTPUT")

    override def toString: String = "Store(output_dir = " + output_dir.expand + ")"

    def prepare_output() { Isabelle_System.mkdirs(output_dir + Path.basic("log")) }

    /* input */

    private val input_dirs =

      if (system_mode) List(output_dir)

      else {

        val ml_ident = Path.explode("$ML_IDENTIFIER").expand

        output_dir :: Path.split(Isabelle_System.getenv_strict("ISABELLE_PATH")).map(_ + ml_ident)

      }

    def find_database_heap(name: String): Option[(Path, Option[String])] =

      input_dirs.find(dir => (dir + database(name)).is_file).map(dir =>

        (dir + database(name), read_heap_digest(dir + Path.basic(name))))

    def find_database(name: String): Option[Path] =

      input_dirs.map(_ + database(name)).find(_.is_file)

    def heap(name: String): Path =

      input_dirs.map(_ + Path.basic(name)).find(_.is_file) getOrElse

        error("Unknown logic " + quote(name) + " -- no heap file found in:\n" +

          cat_lines(input_dirs.map(dir => "  " + dir.expand.implode)))

    /* session info */

    def write_session_info(

      db: SQL.Database,

      name: String,

      build_log: Build_Log.Session_Info,

      build: Build.Session_Info)

    {

      db.transaction {

        db.create_table(Session_Info.table)

        using(Session_Info.delete_statement(db, name))(_.execute)

        using(db.insert_statement(Session_Info.table))(stmt =>

        {

          db.set_string(stmt, 1, name)

          db.set_bytes(stmt, 2, encode_properties(build_log.session_timing))

          db.set_bytes(stmt, 3, compress_properties(build_log.command_timings))

          db.set_bytes(stmt, 4, compress_properties(build_log.ml_statistics))

          db.set_bytes(stmt, 5, compress_properties(build_log.task_statistics))

          db.set_string(stmt, 6, cat_lines(build.sources))

          db.set_string(stmt, 7, cat_lines(build.input_heaps))

          db.set_string(stmt, 8, build.output_heap getOrElse "")

          db.set_int(stmt, 9, build.return_code)

          stmt.execute()

        })

      }

    }

    def read_session_timing(db: SQL.Database, name: String): Properties.T =

      decode_properties(read_bytes(db, name, Session_Info.session_timing))

    def read_command_timings(db: SQL.Database, name: String): List[Properties.T] =

      read_properties(db, name, Session_Info.command_timings)

    def read_ml_statistics(db: SQL.Database, name: String): List[Properties.T] =

      read_properties(db, name, Session_Info.ml_statistics)

    def read_task_statistics(db: SQL.Database, name: String): List[Properties.T] =

      read_properties(db, name, Session_Info.task_statistics)

    def read_build_log(db: SQL.Database, name: String,

      command_timings: Boolean = false,

      ml_statistics: Boolean = false,

      task_statistics: Boolean = false): Build_Log.Session_Info =

    {

      Build_Log.Session_Info(

        session_timing = read_session_timing(db, name),

        command_timings = if (command_timings) read_command_timings(db, name) else Nil,

        ml_statistics = if (ml_statistics) read_ml_statistics(db, name) else Nil,

        task_statistics = if (task_statistics) read_task_statistics(db, name) else Nil)

    }

    def read_build(db: SQL.Database, name: String): Option[Build.Session_Info] =

      using(Session_Info.select_statement(db, name, Session_Info.build_columns))(stmt =>

      {

        val rs = stmt.executeQuery

        if (!rs.next) None

        else {

          Some(

            Build.Session_Info(

              split_lines(db.string(rs, Session_Info.sources)),

              split_lines(db.string(rs, Session_Info.input_heaps)),

              db.string(rs, Session_Info.output_heap) match { case "" => None case s => Some(s) },

              db.int(rs, Session_Info.return_code)))

        }

      })

  }

}