(*  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 node_header = (string * string list * (string * bool) list) Exn.result

   datatype node_edit =

     Clear |

     Edits of (command_id option * command_id option) list |

     Header of node_header

   type edit = string * node_edit

   type state

   val init_state: state

   val join_commands: state -> unit

   val cancel_execution: state -> unit -> 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

   val state: unit -> state

   val change_state: (state -> state) -> unit

 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 **)

 type node_header = (string * string list * (string * bool) list) Exn.result;

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

 abstype node = Node of

  {header: node_header,

   entries: exec_id option Entries.T,  (*command entries with excecutions*)

   result: Toplevel.state lazy}

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

 with

 fun make_node (header, entries, result) =

   Node {header = header, entries = entries, result = result};

 fun map_node f (Node {header, entries, result}) =

   make_node (f (header, entries, result));

 fun get_header (Node {header, ...}) = header;

 fun set_header header = map_node (fn (_, entries, result) => (header, entries, result));

 fun map_entries f (Node {header, entries, result}) = make_node (header, f entries, result);

 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;

 fun get_theory (Node {result, ...}) = Toplevel.end_theory Position.none (Lazy.get_finished result);

 fun set_result result = map_node (fn (header, entries, _) => (header, entries, result));

 val empty_exec = Lazy.value Toplevel.toplevel;

 val empty_node = make_node (Exn.Exn (ERROR "Bad theory header"), Entries.empty, empty_exec);

 val clear_node = map_node (fn (header, _, _) => (header, Entries.empty, empty_exec));

 fun get_node nodes name = Graph.get_node nodes name handle Graph.UNDEF _ => empty_node;

 fun remove_node name nodes = Graph.del_node name nodes handle Graph.UNDEF _ => nodes;

 fun update_node name f = Graph.default_node (name, empty_node) #> Graph.map_node name f;

 (* node edits and associated executions *)

 datatype node_edit =

   Clear |

   Edits of (command_id option * command_id option) list |

   Header of node_header;

 type edit = string * node_edit;

 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) =

   map_entries (Entries.update (id, SOME exec_id));

 fun reset_after id entries =

   (case Entries.get_after entries id of

     NONE => entries

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

 val edit_node = map_entries o fold

   (fn (id, SOME id2) => Entries.insert_after id (id2, NONE)

     | (id, NONE) => Entries.delete_after id #> reset_after id);

 (* version operations *)

 val empty_version = Version Graph.empty;

 fun nodes_of (Version nodes) = nodes;

 val node_of = get_node o nodes_of;

 val node_names_of = Graph.keys o nodes_of;

 fun cycle_msg names = "Cyclic dependency of " ^ space_implode " via " (map quote names);

 fun edit_nodes (name, node_edit) (Version nodes) =

   Version

     (case node_edit of

       Clear => update_node name clear_node nodes

     | Edits edits => update_node name (edit_node edits) nodes

     | Header header =>

         let

           val node = get_node nodes name;

           val nodes' = Graph.new_node (name, node) (remove_node name nodes);

           val parents =

             (case header of Exn.Res (_, parents, _) => parents | _ => [])

             |> filter (can (Graph.get_node nodes'));

           val (header', nodes'') =

             (header, Graph.add_deps_acyclic (name, parents) nodes')

               handle Graph.CYCLES cs => (Exn.Exn (ERROR (cat_lines (map cycle_msg cs))), nodes');

         in Graph.map_node name (set_header header') nodes'' end);

 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: 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, empty_exec)],

     []);

 (* 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 (exec_id, exec) =

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

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

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

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

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

   (case Inttab.lookup execs exec_id of

     NONE => err_undef "command execution" exec_id

   | SOME exec => exec);

 (* document execution *)

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

   (List.app Future.cancel execution;

     fn () => 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, interrupts = true})

       (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 tr st =

   let

     val is_init = Toplevel.is_init 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;

   in

     (case result of

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

     | SOME st' =>

        (Toplevel.status tr Markup.finished;

         proof_status tr st';

         if do_print then async_state tr st' else ();

         st'))

   end;

 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 (command_id, command) (assigns, execs, exec) =

   let

     val exec_id' = new_id ();

     val exec' =

       Lazy.lazy (fn () =>

         let

           val tr = Toplevel.put_id (print_id exec_id') (Future.get_finished command);

           val st = Lazy.get_finished exec;

         in run_command tr st end);

   in ((command_id, exec_id') :: assigns, (exec_id', exec') :: execs, exec') 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 for polyml-5.4.0/x86_64 *)

     val new_version = fold edit_nodes edits old_version;

     (* FIXME futures *)

     val updates =

       nodes_of new_version |> Graph.schedule

         (fn deps => fn (name, node) =>

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

             NONE => (([], [], []), node)

           | 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));

                 fun init () =

                   let

                     val (thy_name, imports, uses) = Exn.release (get_header node);

                     (* FIXME provide files via Scala layer *)

                     val dir = Path.dir (Path.explode name);

                     val files = map (apfst Path.explode) uses;

                     val parents =

                       imports |> map (fn import =>

                         (case AList.lookup (op =) deps import of

                           SOME (_, parent_node) => get_theory parent_node

                         | NONE => Thy_Info.get_theory (Thy_Info.base_name import)));

                   in Thy_Load.begin_theory dir thy_name imports files parents end

                 fun get_command id =

                   (id, the_command state id |> Future.map (Toplevel.modify_init init));

                 val (assigns, execs, result) =

                   fold_entries (SOME id) (new_exec o get_command o #2 o #1)

                     node ([], [], the_exec state prev_exec);

                 val node' = node

                   |> fold update_entry assigns

                   |> set_result result;

               in ((assigns, execs, [(name, node')]), node') end))

       |> map #1;

     val state' = state

       |> fold (fold define_exec o #2) updates

       |> define_version new_id (fold (fold put_node o #3) updates new_version);

   in (maps #1 (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 execution' = (* FIXME Graph.schedule *)

         Future.forks

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

           [fn () =>

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

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

                   (node_of version name) ())];

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

 (** global state **)

 val global_state = Synchronized.var "Document" init_state;

 fun state () = Synchronized.value global_state;

 val change_state = Synchronized.change global_state;

 end;