(*  Title:      Pure/PIDE/document.ML

     Author:     Makarius

 Document as collection of named nodes, each consisting of an editable

 list of commands, associated with asynchronous execution process.

 *)

 signature DOCUMENT =

 sig

   type id = int

   type version_id = id

   type command_id = id

   type exec_id = id

   val no_id: id

   val new_id: unit -> id

   val parse_id: string -> id

   val print_id: id -> string

   type edit = string * ((command_id option * command_id option) list) option

   type state

   val init_state: state

   val cancel: state -> unit

   val define_command: command_id -> string -> state -> state

   val edit: version_id -> version_id -> edit list -> state -> (command_id * exec_id) list * state

   val execute: version_id -> state -> state

 end;

 structure Document: DOCUMENT =

 struct

 (* unique identifiers *)

 type id = int;

 type version_id = id;

 type command_id = id;

 type exec_id = id;

 val no_id = 0;

 val new_id = Synchronized.counter ();

 val parse_id = Markup.parse_int;

 val print_id = Markup.print_int;

 fun err_dup kind id = error ("Duplicate " ^ kind ^ ": " ^ print_id id);

 fun err_undef kind id = error ("Undefined " ^ kind ^ ": " ^ print_id id);

 (** document structure **)

 structure Entries = Linear_Set(type key = command_id val ord = int_ord);

 abstype node = Node of exec_id option Entries.T  (*command entries with excecutions*)

   and version = Version of node Graph.T  (*development graph wrt. static imports*)

 with

 val empty_node = Node Entries.empty;

 val empty_version = Version Graph.empty;

 fun fold_entries start f (Node entries) = Entries.fold start f entries;

 fun first_entry start P (Node entries) = Entries.get_first start P entries;

 (* node edits and associated executions *)

 type edit =

   string *

   (*NONE: remove node, SOME: insert/remove commands*)

   ((command_id option * command_id option) list) option;

 fun the_entry (Node entries) id =

   (case Entries.lookup entries id of

     NONE => err_undef "command entry" id

   | SOME entry => entry);

 fun update_entry (id, exec_id) (Node entries) =

   Node (Entries.update (id, SOME exec_id) entries);

 fun reset_after id entries =

   (case Entries.get_after entries id of

     NONE => entries

   | SOME next => Entries.update (next, NONE) entries);

 fun edit_node (id, SOME id2) (Node entries) =

       Node (Entries.insert_after id (id2, NONE) entries)

   | edit_node (id, NONE) (Node entries) =

       Node (entries |> Entries.delete_after id |> reset_after id);

 (* version operations *)

 fun nodes_of (Version nodes) = nodes;

 val node_names_of = Graph.keys o nodes_of;

 fun get_node version name = Graph.get_node (nodes_of version) name

   handle Graph.UNDEF _ => empty_node;

 fun edit_nodes (name, SOME edits) (Version nodes) =

       Version (nodes

         |> Graph.default_node (name, empty_node)

         |> Graph.map_node name (fold edit_node edits))

   | edit_nodes (name, NONE) (Version nodes) =

       Version (perhaps (try (Graph.del_node name)) nodes);

 fun put_node name node (Version nodes) =

   Version (nodes

     |> Graph.default_node (name, empty_node)

     |> Graph.map_node name (K node));

 end;

 (** global state -- document structure and execution process **)

 abstype state = State of

  {versions: version Inttab.table,  (*version_id -> document content*)

   commands: Toplevel.transition future Inttab.table,  (*command_id -> transition (future parsing)*)

   execs: (bool * Toplevel.state) lazy Inttab.table,  (*exec_id -> execution process*)

   execution: unit future list}  (*global execution process*)

 with

 fun make_state (versions, commands, execs, execution) =

   State {versions = versions, commands = commands, execs = execs, execution = execution};

 fun map_state f (State {versions, commands, execs, execution}) =

   make_state (f (versions, commands, execs, execution));

 val init_state =

   make_state (Inttab.make [(no_id, empty_version)],

     Inttab.make [(no_id, Future.value Toplevel.empty)],

     Inttab.make [(no_id, Lazy.value (true, Toplevel.toplevel))],

     []);

 (* document versions *)

 fun define_version (id: version_id) version =

   map_state (fn (versions, commands, execs, execution) =>

     let val versions' = Inttab.update_new (id, version) versions

       handle Inttab.DUP dup => err_dup "document version" dup

     in (versions', commands, execs, execution) end);

 fun the_version (State {versions, ...}) (id: version_id) =

   (case Inttab.lookup versions id of

     NONE => err_undef "document version" id

   | SOME version => version);

 (* commands *)

 fun define_command (id: command_id) text =

   map_state (fn (versions, commands, execs, execution) =>

     let

       val id_string = print_id id;

       val tr = Future.fork_pri 2 (fn () =>

         Position.setmp_thread_data (Position.id_only id_string)

           (fn () => Outer_Syntax.prepare_command (Position.id id_string) text) ());

       val commands' =

         Inttab.update_new (id, tr) commands

           handle Inttab.DUP dup => err_dup "command" dup;

     in (versions, commands', execs, execution) end);

 fun the_command (State {commands, ...}) (id: command_id) =

   (case Inttab.lookup commands id of

     NONE => err_undef "command" id

   | SOME tr => tr);

 fun join_commands (State {commands, ...}) =

   Inttab.fold (fn (_, tr) => fn () => ignore (Future.join_result tr)) commands ();

 (* command executions *)

 fun define_exec (id: exec_id) exec =

   map_state (fn (versions, commands, execs, execution) =>

     let val execs' = Inttab.update_new (id, exec) execs

       handle Inttab.DUP dup => err_dup "command execution" dup

     in (versions, commands, execs', execution) end);

 fun the_exec (State {execs, ...}) (id: exec_id) =

   (case Inttab.lookup execs id of

     NONE => err_undef "command execution" id

   | SOME exec => exec);

 (* document execution *)

 fun cancel (State {execution, ...}) =

   List.app Future.cancel execution;

 fun await_cancellation (State {execution, ...}) =

   ignore (Future.join_results execution);

 end;

 (* toplevel transactions *)

 local

 fun timing tr t = Toplevel.status tr (Markup.timing t);

 fun proof_status tr st =

   (case try Toplevel.proof_of st of

     SOME prf => Toplevel.status tr (Proof.status_markup prf)

   | NONE => ());

 fun async_state tr st =

   ignore

     (singleton

       (Future.forks {name = "Document.async_state",

         group = SOME (Task_Queue.new_group NONE), deps = [], pri = 0})

       (fn () =>

         Toplevel.setmp_thread_position tr

           (fn () => Toplevel.print_state false st) ()));

 fun run int tr st =

   (case Toplevel.transition int tr st of

     SOME (st', NONE) => ([], SOME st')

   | SOME (_, SOME exn_info) =>

       (case ML_Compiler.exn_messages (Runtime.EXCURSION_FAIL exn_info) of

         [] => Exn.interrupt ()

       | errs => (errs, NONE))

   | NONE => ([ML_Compiler.exn_message Runtime.TERMINATE], NONE));

 in

 fun run_command thy_name raw_tr st =

   (case

       (case Toplevel.init_of raw_tr of

         SOME name => Exn.capture (fn () =>

           let

             val path = Path.explode thy_name;

             val _ = Thy_Header.consistent_name (Path.implode (Path.base path)) name;

           in Toplevel.modify_master (SOME (Path.dir path)) raw_tr end) ()

       | NONE => Exn.Result raw_tr) of

     Exn.Result tr =>

       let

         val is_init = is_some (Toplevel.init_of tr);

         val is_proof = Keyword.is_proof (Toplevel.name_of tr);

         val do_print = not is_init andalso (Toplevel.print_of tr orelse is_proof);

         val start = Timing.start ();

         val (errs, result) =

           if Toplevel.is_toplevel st andalso not is_init then ([], SOME st)

           else run (is_init orelse is_proof) (Toplevel.set_print false tr) st;

         val _ = timing tr (Timing.result start);

         val _ = List.app (Toplevel.error_msg tr) errs;

         val res =

           (case result of

             NONE => (Toplevel.status tr Markup.failed; (false, st))

           | SOME st' =>

              (Toplevel.status tr Markup.finished;

               proof_status tr st';

               if do_print then async_state tr st' else ();

               (true, st')));

       in res end

   | Exn.Exn exn =>

       if Exn.is_interrupt exn then reraise exn

       else

        (Toplevel.error_msg raw_tr (ML_Compiler.exn_message exn);

         Toplevel.status raw_tr Markup.failed;

         (false, Toplevel.toplevel)));

 end;

 (** editing **)

 (* edit *)

 local

 fun is_changed node' ((_, id), exec) =

   (case try (the_entry node') id of

     NONE => true

   | SOME exec' => exec' <> exec);

 fun new_exec name (id: command_id) (exec_id, updates, state) =

   let

     val exec = the_exec state exec_id;

     val exec_id' = new_id ();

     val future_tr = the_command state id;

     val exec' =

       Lazy.lazy (fn () =>

         let

           val st = #2 (Lazy.force exec);

           val exec_tr = Toplevel.put_id (print_id exec_id') (Future.join future_tr);

         in run_command name exec_tr st end);

     val state' = define_exec exec_id' exec' state;

   in (exec_id', (id, exec_id') :: updates, state') end;

 in

 fun edit (old_id: version_id) (new_id: version_id) edits state =

   let

     val old_version = the_version state old_id;

     val _ = Time.now ();  (* FIXME odd workaround *)

     val new_version = fold edit_nodes edits old_version;

     fun update_node name (rev_updates, version, st) =

       let val node = get_node version name in

         (case first_entry NONE (is_changed (get_node old_version name)) node of

           NONE => (rev_updates, version, st)

         | SOME ((prev, id), _) =>

             let

               val prev_exec =

                 (case prev of

                   NONE => no_id

                 | SOME prev_id => the_default no_id (the_entry node prev_id));

               val (_, rev_upds, st') =

                 fold_entries (SOME id) (new_exec name o #2 o #1) node (prev_exec, [], st);

               val node' = fold update_entry rev_upds node;

             in (rev_upds @ rev_updates, put_node name node' version, st') end)

       end;

     (* FIXME proper node deps *)

     val (rev_updates, new_version', state') =

       fold update_node (node_names_of new_version) ([], new_version, state);

     val state'' = define_version new_id new_version' state';

     val _ = join_commands state'';  (* FIXME async!? *)

   in (rev rev_updates, state'') end;

 end;

 (* execute *)

 fun execute version_id state =

   state |> map_state (fn (versions, commands, execs, _) =>

     let

       val version = the_version state version_id;

       fun force_exec NONE = ()

         | force_exec (SOME exec_id) = ignore (Lazy.force (the_exec state exec_id));

       val _ = cancel state;

       val execution' = (* FIXME proper node deps *)

         Future.forks {name = "Document.execute", group = NONE, deps = [], pri = 1}

           [fn () =>

             let

               val _ = await_cancellation state;

               val _ =

                 node_names_of version |> List.app (fn name =>

                   fold_entries NONE (fn (_, exec) => fn () => force_exec exec)

                       (get_node version name) ());

             in () end];

       val _ = await_cancellation state;  (* FIXME async!? *)

     in (versions, commands, execs, execution') end);

 end;