(*  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

  val timing: bool Unsynchronized.ref

  type node_header = string * Thy_Header.header * string list

  type overlay = Document_ID.command * (string * string list)

  datatype node_edit =

    Clear |    (* FIXME unused !? *)

    Edits of (Document_ID.command option * Document_ID.command option) list |

    Deps of node_header |

    Perspective of bool * Document_ID.command list * overlay list

  type edit = string * node_edit

  type state

  val init_state: state

  val define_blob: string -> string -> state -> state

  val define_command: Document_ID.command -> string -> Command.blob list -> string ->

    state -> state

  val remove_versions: Document_ID.version list -> state -> state

  val start_execution: state -> state

  val update: Document_ID.version -> Document_ID.version -> edit list -> state ->

    Document_ID.exec list * (Document_ID.command * Document_ID.exec list) list * state

  val state: unit -> state

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

end;

structure Document: DOCUMENT =

struct

val timing = Unsynchronized.ref false;

fun timeit msg e = cond_timeit (! timing) msg e;

(** document structure **)

fun err_dup kind id = error ("Duplicate " ^ kind ^ ": " ^ Document_ID.print id);

fun err_undef kind id = error ("Undefined " ^ kind ^ ": " ^ Document_ID.print id);

type node_header = string * Thy_Header.header * string list;

type perspective =

 {required: bool,  (*required node*)

  visible: Inttab.set,  (*visible commands*)

  visible_last: Document_ID.command option,  (*last visible command*)

  overlays: (string * string list) list Inttab.table};  (*command id -> print function with args*)

structure Entries = Linear_Set(type key = Document_ID.command val ord = int_ord);

abstype node = Node of

 {header: node_header,  (*master directory, theory header, errors*)

  perspective: perspective,  (*command perspective*)

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

  result: Command.eval option}  (*result of last execution*)

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

with

fun make_node (header, perspective, entries, result) =

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

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

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

fun make_perspective (required, command_ids, overlays) : perspective =

 {required = required,

  visible = Inttab.make_set command_ids,

  visible_last = try List.last command_ids,

  overlays = Inttab.make_list overlays};

val no_header = ("", Thy_Header.make ("", Position.none) [] [], ["No theory header"]);

val no_perspective = make_perspective (false, [], []);

val empty_node = make_node (no_header, no_perspective, Entries.empty, NONE);

val clear_node = map_node (fn (header, _, _, _) => (header, no_perspective, Entries.empty, NONE));

(* basic components *)

fun master_directory (Node {header = (master, _, _), ...}) =

  (case try Url.explode master of

    SOME (Url.File path) => path

  | _ => Path.current);

fun set_header header =

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

fun get_header (Node {header = (master, header, errors), ...}) =

  if null errors then (master, header)

  else error (cat_lines errors);

fun read_header node span =

  let

    val {name = (name, _), imports, keywords} = #2 (get_header node);

    val {name = (_, pos), imports = imports', ...} = Thy_Header.read_tokens span;

  in Thy_Header.make (name, pos) (map #1 imports ~~ map #2 imports') keywords end;

fun get_perspective (Node {perspective, ...}) = perspective;

fun set_perspective args =

  map_node (fn (header, _, entries, result) => (header, make_perspective args, entries, result));

val required_node = #required o get_perspective;

val visible_command = Inttab.defined o #visible o get_perspective;

val visible_last = #visible_last o get_perspective;

val visible_node = is_some o visible_last

val overlays = Inttab.lookup_list o #overlays o get_perspective;

fun map_entries f =

  map_node (fn (header, perspective, entries, result) => (header, perspective, f entries, result));

fun get_entries (Node {entries, ...}) = entries;

fun iterate_entries f = Entries.iterate NONE f o get_entries;

fun iterate_entries_after start f (Node {entries, ...}) =

  (case Entries.get_after entries start of

    NONE => I

  | SOME id => Entries.iterate (SOME id) f entries);

fun get_result (Node {result, ...}) = result;

fun set_result result =

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

fun changed_result node node' =

  (case (get_result node, get_result node') of

    (SOME eval, SOME eval') => not (Command.eval_eq (eval, eval'))

  | (NONE, NONE) => false

  | _ => true);

fun pending_result node =

  (case get_result node of

    SOME eval => not (Command.eval_finished eval)

  | NONE => false);

fun get_node nodes name = String_Graph.get_node nodes name

  handle String_Graph.UNDEF _ => empty_node;

fun default_node name = String_Graph.default_node (name, empty_node);

fun update_node name f = default_node name #> String_Graph.map_node name f;

(* node edits and associated executions *)

type overlay = Document_ID.command * (string * string list);

datatype node_edit =

  Clear |

  Edits of (Document_ID.command option * Document_ID.command option) list |

  Deps of node_header |

  Perspective of bool * Document_ID.command list * overlay list;

type edit = string * node_edit;

val after_entry = Entries.get_after o get_entries;

fun lookup_entry node id =

  (case Entries.lookup (get_entries node) id of

    NONE => NONE

  | SOME (exec, _) => exec);

fun the_entry node id =

  (case Entries.lookup (get_entries node) id of

    NONE => err_undef "command entry" id

  | SOME (exec, _) => exec);

fun the_default_entry node (SOME id) = (id, the_default Command.no_exec (the_entry node id))

  | the_default_entry _ NONE = (Document_ID.none, Command.no_exec);

fun assign_entry (command_id, exec) node =

  if is_none (Entries.lookup (get_entries node) command_id) then node

  else map_entries (Entries.update (command_id, exec)) node;

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 String_Graph.empty;

fun nodes_of (Version nodes) = nodes;

val node_of = get_node 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

    | Deps (master, header, errors) =>

        let

          val imports = map fst (#imports header);

          val errors1 =

            (Thy_Header.define_keywords header; errors)

              handle ERROR msg => errors @ [msg];

          val nodes1 = nodes

            |> default_node name

            |> fold default_node imports;

          val nodes2 = nodes1

            |> String_Graph.Keys.fold

                (fn dep => String_Graph.del_edge (dep, name)) (String_Graph.imm_preds nodes1 name);

          val (nodes3, errors2) =

            (String_Graph.add_deps_acyclic (name, imports) nodes2, errors1)

              handle String_Graph.CYCLES cs => (nodes2, errors1 @ map cycle_msg cs);

        in String_Graph.map_node name (set_header (master, header, errors2)) nodes3 end

    | Perspective perspective => update_node name (set_perspective perspective) nodes);

fun put_node (name, node) (Version nodes) =

  Version (update_node name (K node) nodes);

end;

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

type execution =

 {version_id: Document_ID.version,  (*static version id*)

  execution_id: Document_ID.execution,  (*dynamic execution id*)

  delay_request: unit future,  (*pending event timer request*)

  frontier: Future.task Symtab.table};  (*node name -> running execution task*)

val no_execution: execution =

  {version_id = Document_ID.none, execution_id = Document_ID.none,

   delay_request = Future.value (), frontier = Symtab.empty};

fun new_execution version_id delay_request frontier : execution =

  {version_id = version_id, execution_id = Execution.start (),

   delay_request = delay_request, frontier = frontier};

abstype state = State of

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

  blobs: string Symtab.table,  (*digest -> text*)

  commands: (string * Command.blob list * Token.T list lazy) Inttab.table,

    (*command id -> name, inlined files, command span*)

  execution: execution}  (*current execution process*)

with

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

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

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

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

val init_state =

  make_state (Inttab.make [(Document_ID.none, empty_version)],

    Symtab.empty, Inttab.empty, no_execution);

(* document versions *)

fun define_version version_id version =

  map_state (fn (versions, blobs, commands, {delay_request, frontier, ...}) =>

    let

      val versions' = Inttab.update_new (version_id, version) versions

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

      val execution' = new_execution version_id delay_request frontier;

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

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

  (case Inttab.lookup versions version_id of

    NONE => err_undef "document version" version_id

  | SOME version => version);

fun delete_version version_id versions =

  Inttab.delete version_id versions

    handle Inttab.UNDEF _ => err_undef "document version" version_id;

(* inlined files *)

fun define_blob digest text =

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

    let val blobs' = Symtab.update (digest, text) blobs

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

fun the_blob (State {blobs, ...}) digest =

  (case Symtab.lookup blobs digest of

    NONE => error ("Undefined blob: " ^ digest)

  | SOME text => text);

(* commands *)

fun define_command command_id name command_blobs text =

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

    let

      val id = Document_ID.print command_id;

      val span =

        Lazy.lazy (fn () =>

          Position.setmp_thread_data (Position.id_only id)

            (fn () => Thy_Syntax.parse_tokens (Keyword.get_lexicons ()) (Position.id id) text) ());

      val _ =

        Position.setmp_thread_data (Position.id_only id)

          (fn () => Output.status (Markup.markup_only Markup.accepted)) ();

      val commands' =

        Inttab.update_new (command_id, (name, command_blobs, span)) commands

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

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

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

  (case Inttab.lookup commands command_id of

    NONE => err_undef "command" command_id

  | SOME command => command);

val the_command_name = #1 oo the_command;

end;

(* remove_versions *)

fun remove_versions version_ids state = state |> map_state (fn (versions, _, _, execution) =>

  let

    val _ =

      member (op =) version_ids (#version_id execution) andalso

        error ("Attempt to remove execution version " ^ Document_ID.print (#version_id execution));

    val versions' = fold delete_version version_ids versions;

    val commands' =

      (versions', Inttab.empty) |->

        Inttab.fold (fn (_, version) => nodes_of version |>

          String_Graph.fold (fn (_, (node, _)) => node |>

            iterate_entries (fn ((_, command_id), _) =>

              SOME o Inttab.insert (K true) (command_id, the_command state command_id))));

    val blobs' =

      (commands', Symtab.empty) |->

        Inttab.fold (fn (_, (_, blobs, _)) => blobs |>

          fold (fn Exn.Res (_, SOME b) => Symtab.update (b, the_blob state b) | _ => I));

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

(* document execution *)

fun start_execution state = state |> map_state (fn (versions, blobs, commands, execution) =>

  timeit "Document.start_execution" (fn () =>

    let

      val {version_id, execution_id, delay_request, frontier} = execution;

      val delay = seconds (Options.default_real "editor_execution_delay");

      val _ = Future.cancel delay_request;

      val delay_request' = Event_Timer.future (Time.+ (Time.now (), delay));

      val new_tasks =

        nodes_of (the_version state version_id) |> String_Graph.schedule

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

            if visible_node node orelse pending_result node then

              let

                val more_deps =

                  Future.task_of delay_request' :: the_list (Symtab.lookup frontier name);

                fun body () =

                  iterate_entries (fn (_, opt_exec) => fn () =>

                    (case opt_exec of

                      SOME exec =>

                        if Execution.is_running execution_id

                        then SOME (Command.exec execution_id exec)

                        else NONE

                    | NONE => NONE)) node ()

                  handle exn => if Exn.is_interrupt exn then () (*sic!*) else reraise exn;

                val future =

                  (singleton o Future.forks)

                    {name = "theory:" ^ name, group = SOME (Future.new_group NONE),

                      deps = more_deps @ map #2 (maps #2 deps),

                      pri = 0, interrupts = false} body;

              in [(name, Future.task_of future)] end

            else []);

      val frontier' = (fold o fold) Symtab.update new_tasks frontier;

      val execution' =

        {version_id = version_id, execution_id = execution_id,

         delay_request = delay_request', frontier = frontier'};

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

(** document update **)

(* exec state assignment *)

type assign_update = Command.exec option Inttab.table;  (*command id -> exec*)

val assign_update_empty: assign_update = Inttab.empty;

fun assign_update_defined (tab: assign_update) command_id = Inttab.defined tab command_id;

fun assign_update_apply (tab: assign_update) node = Inttab.fold assign_entry tab node;

fun assign_update_new upd (tab: assign_update) =

  Inttab.update_new upd tab

    handle Inttab.DUP dup => err_dup "exec state assignment" dup;

fun assign_update_result (tab: assign_update) =

  Inttab.fold (fn (command_id, exec) => cons (command_id, Command.exec_ids exec)) tab [];

(* update *)

local

fun make_required nodes =

  let

    fun all_preds P =

      String_Graph.fold (fn (a, (node, _)) => P node ? cons a) nodes []

      |> String_Graph.all_preds nodes

      |> Symtab.make_set;

    val all_visible = all_preds visible_node;

    val all_required = all_preds required_node;

  in

    Symtab.fold (fn (a, ()) =>

      exists (Symtab.defined all_visible) (String_Graph.immediate_succs nodes a) ?

        Symtab.update (a, ())) all_visible all_required

  end;

fun loaded_theory name =

  (case try (unsuffix ".thy") name of

    SOME a => Thy_Info.lookup_theory a

  | NONE => NONE);

fun init_theory deps node span =

  let

    val master_dir = master_directory node;

    val header = read_header node span;

    val imports = #imports header;

    val parents =

      imports |> map (fn (import, _) =>

        (case loaded_theory import of

          SOME thy => thy

        | NONE =>

            Toplevel.end_theory (Position.file_only import)

              (case get_result (snd (the (AList.lookup (op =) deps import))) of

                NONE => Toplevel.toplevel

              | SOME eval => Command.eval_result_state eval)));

    val _ = Position.reports (map #2 imports ~~ map Theory.get_markup parents);

  in Thy_Load.begin_theory master_dir header parents end;

fun check_theory full name node =

  is_some (loaded_theory name) orelse

  can get_header node andalso (not full orelse is_some (get_result node));

fun last_common state node_required node0 node =

  let

    fun update_flags prev (visible, initial) =

      let

        val visible' = visible andalso prev <> visible_last node;

        val initial' = initial andalso

          (case prev of

            NONE => true

          | SOME command_id => not (Keyword.is_theory_begin (the_command_name state command_id)));

      in (visible', initial') end;

    fun get_common ((prev, command_id), opt_exec) (_, ok, flags, assign_update) =

      if ok then

        let

          val flags' as (visible', _) = update_flags prev flags;

          val ok' =

            (case (lookup_entry node0 command_id, opt_exec) of

              (SOME (eval0, _), SOME (eval, _)) =>

                Command.eval_eq (eval0, eval) andalso

                  (visible' orelse node_required orelse Command.eval_running eval)

            | _ => false);

          val assign_update' = assign_update |> ok' ?

            (case opt_exec of

              SOME (eval, prints) =>

                let

                  val command_visible = visible_command node command_id;

                  val command_overlays = overlays node command_id;

                  val command_name = the_command_name state command_id;

                in

                  (case Command.print command_visible command_overlays command_name eval prints of

                    SOME prints' => assign_update_new (command_id, SOME (eval, prints'))

                  | NONE => I)

                end

            | NONE => I);

        in SOME (prev, ok', flags', assign_update') end

      else NONE;

    val (common, ok, flags, assign_update') =

      iterate_entries get_common node (NONE, true, (true, true), assign_update_empty);

    val (common', flags') =

      if ok then

        let val last = Entries.get_after (get_entries node) common

        in (last, update_flags last flags) end

      else (common, flags);

  in (assign_update', common', flags') end;

fun illegal_init _ = error "Illegal theory header after end of theory";

fun new_exec state node proper_init command_id' (assign_update, command_exec, init) =

  if not proper_init andalso is_none init then NONE

  else

    let

      val (_, (eval, _)) = command_exec;

      val command_visible = visible_command node command_id';

      val command_overlays = overlays node command_id';

      val (command_name, blobs0, span0) = the_command state command_id';

      val blobs = (map o Exn.map_result o apsnd o Option.map) (the_blob state) blobs0;

      val span = Lazy.force span0;

      val eval' =

        Command.eval (fn () => the_default illegal_init init span)

          (master_directory node) blobs span eval;

      val prints' = perhaps (Command.print command_visible command_overlays command_name eval') [];

      val exec' = (eval', prints');

      val assign_update' = assign_update_new (command_id', SOME exec') assign_update;

      val init' = if Keyword.is_theory_begin command_name then NONE else init;

    in SOME (assign_update', (command_id', (eval', prints')), init') end;

fun removed_execs node0 (command_id, exec_ids) =

  subtract (op =) exec_ids (Command.exec_ids (lookup_entry node0 command_id));

in

fun update old_version_id new_version_id edits state =

  let

    val old_version = the_version state old_version_id;

    val new_version = timeit "Document.edit_nodes" (fn () => fold edit_nodes edits old_version);

    val nodes = nodes_of new_version;

    val required = make_required nodes;

    val required0 = make_required (nodes_of old_version);

    val edited = fold (fn (name, _) => Symtab.update (name, ())) edits Symtab.empty;

    val updated = timeit "Document.update" (fn () =>

      nodes |> String_Graph.schedule

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

          (singleton o Future.forks)

            {name = "Document.update", group = NONE,

              deps = map (Future.task_of o #2) deps, pri = 1, interrupts = false}

            (fn () => timeit ("Document.update " ^ name) (fn () =>

              let

                val imports = map (apsnd Future.join) deps;

                val imports_result_changed = exists (#4 o #1 o #2) imports;

                val node_required = Symtab.defined required name;

              in

                if Symtab.defined edited name orelse visible_node node orelse

                  imports_result_changed orelse Symtab.defined required0 name <> node_required

                then

                  let

                    val node0 = node_of old_version name;

                    val init = init_theory imports node;

                    val proper_init =

                      check_theory false name node andalso

                      forall (fn (name, (_, node)) => check_theory true name node) imports;

                    val (print_execs, common, (still_visible, initial)) =

                      if imports_result_changed then (assign_update_empty, NONE, (true, true))

                      else last_common state node_required node0 node;

                    val common_command_exec = the_default_entry node common;

                    val (updated_execs, (command_id', (eval', _)), _) =

                      (print_execs, common_command_exec, if initial then SOME init else NONE)

                      |> (still_visible orelse node_required) ?

                        iterate_entries_after common

                          (fn ((prev, id), _) => fn res =>

                            if not node_required andalso prev = visible_last node then NONE

                            else new_exec state node proper_init id res) node;

                    val assigned_execs =

                      (node0, updated_execs) |-> iterate_entries_after common

                        (fn ((_, command_id0), exec0) => fn res =>

                          if is_none exec0 then NONE

                          else if assign_update_defined updated_execs command_id0 then SOME res

                          else SOME (assign_update_new (command_id0, NONE) res));

                    val last_exec =

                      if command_id' = Document_ID.none then NONE else SOME command_id';

                    val result =

                      if is_none last_exec orelse is_some (after_entry node last_exec) then NONE

                      else SOME eval';

                    val assign_update = assign_update_result assigned_execs;

                    val removed = maps (removed_execs node0) assign_update;

                    val _ = List.app Execution.cancel removed;

                    val node' = node

                      |> assign_update_apply assigned_execs

                      |> set_result result;

                    val assigned_node = SOME (name, node');

                    val result_changed = changed_result node0 node';

                  in ((removed, assign_update, assigned_node, result_changed), node') end

                else (([], [], NONE, false), node)

              end)))

      |> Future.joins |> map #1);

    val removed = maps #1 updated;

    val assign_update = maps #2 updated;

    val assigned_nodes = map_filter #3 updated;

    val state' = state

      |> define_version new_version_id (fold put_node assigned_nodes new_version);

  in (removed, assign_update, state') end;

end;

(** global state **)

val global_state = Synchronized.var "Document.global_state" init_state;

fun state () = Synchronized.value global_state;

val change_state = Synchronized.change global_state;

end;