(*  Title:      HOL/Tools/ATP_Manager/atp_manager.ML

     Author:     Fabian Immler, TU Muenchen

 ATP threads are registered here.

 Threads with the same birth-time are seen as one group.

 All threads of a group are killed when one thread of it has been successful,

 or after a certain time,

 or when the maximum number of threads exceeds; then the oldest thread is killed.

 *)

 signature ATP_MANAGER =

 sig

   val get_atps: unit -> string

   val set_atps: string -> unit

   val get_max_atps: unit -> int

   val set_max_atps: int -> unit

   val get_timeout: unit -> int

   val set_timeout: int -> unit

   val get_full_types: unit -> bool

   val set_full_types: bool -> unit

   val kill: unit -> unit

   val info: unit -> unit

   val messages: int option -> unit

   type prover = int -> (thm * (string * int)) list option ->

     (thm * (string * int)) list option -> string -> int ->

     Proof.context * (thm list * thm) ->

     bool * string * string * string vector * (thm * (string * int)) list

   val add_prover: string -> prover -> theory -> theory

   val print_provers: theory -> unit

   val get_prover: string -> theory -> prover option

   val sledgehammer: string list -> Proof.state -> unit

 end;

 structure AtpManager: ATP_MANAGER =

 struct

 (** preferences **)

 val message_store_limit = 20;

 val message_display_limit = 5;

 local

 val atps = ref "e remote_vampire";

 val max_atps = ref 5;   (* ~1 means infinite number of atps *)

 val timeout = ref 60;

 val full_types = ref false;

 in

 fun get_atps () = CRITICAL (fn () => ! atps);

 fun set_atps str = CRITICAL (fn () => atps := str);

 fun get_max_atps () = CRITICAL (fn () => ! max_atps);

 fun set_max_atps number = CRITICAL (fn () => max_atps := number);

 fun get_timeout () = CRITICAL (fn () => ! timeout);

 fun set_timeout time = CRITICAL (fn () => timeout := time);

 fun get_full_types () = CRITICAL (fn () => ! full_types);

 fun set_full_types bool = CRITICAL (fn () => full_types := bool);

 val _ =

   ProofGeneralPgip.add_preference Preferences.category_proof

     (Preferences.string_pref atps

       "ATP: provers" "Default automatic provers (separated by whitespace)");

 val _ =

   ProofGeneralPgip.add_preference Preferences.category_proof

     (Preferences.int_pref max_atps

       "ATP: maximum number" "How many provers may run in parallel");

 val _ =

   ProofGeneralPgip.add_preference Preferences.category_proof

     (Preferences.int_pref timeout

       "ATP: timeout" "ATPs will be interrupted after this time (in seconds)");

 val _ =

   ProofGeneralPgip.add_preference Preferences.category_proof

     (Preferences.bool_pref full_types

       "ATP: full types" "ATPs will use full type information");

 end;

 (** thread management **)

 (* data structures over threads *)

 structure ThreadHeap = HeapFun

 (

   type elem = Time.time * Thread.thread;

   fun ord ((a, _), (b, _)) = Time.compare (a, b);

 );

 fun lookup_thread xs = AList.lookup Thread.equal xs;

 fun delete_thread xs = AList.delete Thread.equal xs;

 fun update_thread xs = AList.update Thread.equal xs;

 (* state of thread manager *)

 datatype T = State of

  {managing_thread: Thread.thread option,

   timeout_heap: ThreadHeap.T,

   oldest_heap: ThreadHeap.T,

   active: (Thread.thread * (Time.time * Time.time * string)) list,

   cancelling: (Thread.thread * (Time.time * Time.time * string)) list,

   messages: string list,

   store: string list};

 fun make_state managing_thread timeout_heap oldest_heap active cancelling messages store =

   State {managing_thread = managing_thread, timeout_heap = timeout_heap, oldest_heap = oldest_heap,

     active = active, cancelling = cancelling, messages = messages, store = store};

 val state = Synchronized.var "atp_manager"

   (make_state NONE ThreadHeap.empty ThreadHeap.empty [] [] [] []);

 (* unregister thread *)

 fun unregister (success, message) thread = Synchronized.change state

   (fn state as State {managing_thread, timeout_heap, oldest_heap, active, cancelling, messages, store} =>

     (case lookup_thread active thread of

       SOME (birthtime, _, description) =>

         let

           val (group, active') =

             if success then List.partition (fn (_, (tb, _, _)) => tb = birthtime) active

             else List.partition (fn (th, _) => Thread.equal (th, thread)) active

           val now = Time.now ()

           val cancelling' =

             fold (fn (th, (tb, _, desc)) => update_thread (th, (tb, now, desc))) group cancelling

           val message' = description ^ "\n" ^ message ^

             (if length group <= 1 then ""

              else "\nInterrupted " ^ string_of_int (length group - 1) ^ " other group members")

           val store' = message' ::

             (if length store <= message_store_limit then store

              else #1 (chop message_store_limit store))

         in make_state

           managing_thread timeout_heap oldest_heap active' cancelling' (message' :: messages) store'

         end

     | NONE => state));

 (* kill excessive atp threads *)

 fun excessive_atps active =

   let val max = get_max_atps ()

   in length active > max andalso max > ~1 end;

 local

 fun kill_oldest () =

   let exception Unchanged in

     Synchronized.change_result state

       (fn State {managing_thread, timeout_heap, oldest_heap, active, cancelling, messages, store} =>

         if ThreadHeap.is_empty oldest_heap orelse not (excessive_atps active)

         then raise Unchanged

         else

           let val ((_, oldest_thread), oldest_heap') = ThreadHeap.min_elem oldest_heap

           in (oldest_thread,

           make_state managing_thread timeout_heap oldest_heap' active cancelling messages store) end)

       |> unregister (false, "Interrupted (maximum number of ATPs exceeded)")

     handle Unchanged => ()

   end;

 in

 fun kill_excessive () =

   let val State {active, ...} = Synchronized.value state

   in if excessive_atps active then (kill_oldest (); kill_excessive ()) else () end;

 end;

 fun print_new_messages () =

   let val to_print = Synchronized.change_result state

     (fn State {managing_thread, timeout_heap, oldest_heap, active, cancelling, messages, store} =>

       (messages, make_state managing_thread timeout_heap oldest_heap active cancelling [] store))

   in

     if null to_print then ()

     else priority ("Sledgehammer: " ^ space_implode "\n\n" to_print)

   end;

 (* start a watching thread -- only one may exist *)

 fun check_thread_manager () = Synchronized.change state

   (fn State {managing_thread, timeout_heap, oldest_heap, active, cancelling, messages, store} =>

     if (case managing_thread of SOME thread => Thread.isActive thread | NONE => false)

     then make_state managing_thread timeout_heap oldest_heap active cancelling messages store

     else let val managing_thread = SOME (SimpleThread.fork false (fn () =>

       let

         val min_wait_time = Time.fromMilliseconds 300

         val max_wait_time = Time.fromSeconds 10

         (* wait for next thread to cancel, or maximum*)

         fun time_limit (State {timeout_heap, ...}) =

           (case try ThreadHeap.min timeout_heap of

             NONE => SOME (Time.+ (Time.now (), max_wait_time))

           | SOME (time, _) => SOME time)

         (* action: find threads whose timeout is reached, and interrupt cancelling threads *)

         fun action (State {managing_thread, timeout_heap, oldest_heap, active, cancelling,

                            messages, store}) =

           let val (timeout_threads, timeout_heap') =

             ThreadHeap.upto (Time.now (), Thread.self ()) timeout_heap

           in

             if null timeout_threads andalso null cancelling andalso not (excessive_atps active)

             then NONE

             else

               let

                 val _ = List.app (SimpleThread.interrupt o #1) cancelling

                 val cancelling' = filter (Thread.isActive o #1) cancelling

                 val state' = make_state

                   managing_thread timeout_heap' oldest_heap active cancelling' messages store

               in SOME (map #2 timeout_threads, state') end

           end

       in

         while Synchronized.change_result state

           (fn st as

             State {managing_thread, timeout_heap, oldest_heap, active, cancelling, messages, store} =>

             if (null active) andalso (null cancelling) andalso (null messages)

             then (false, make_state NONE timeout_heap oldest_heap active cancelling messages store)

             else (true, st))

         do

           (Synchronized.timed_access state time_limit action

             |> these

             |> List.app (unregister (false, "Interrupted (reached timeout)"));

             kill_excessive ();

             print_new_messages ();

             (*give threads time to respond to interrupt*)

             OS.Process.sleep min_wait_time)

       end))

     in make_state managing_thread timeout_heap oldest_heap active cancelling messages store end);

 (* thread is registered here by sledgehammer *)

 fun register birthtime deadtime (thread, desc) =

  (Synchronized.change state

     (fn State {managing_thread, timeout_heap, oldest_heap, active, cancelling, messages, store} =>

       let

         val timeout_heap' = ThreadHeap.insert (deadtime, thread) timeout_heap

         val oldest_heap' = ThreadHeap.insert (birthtime, thread) oldest_heap

         val active' = update_thread (thread, (birthtime, deadtime, desc)) active

       in make_state managing_thread timeout_heap' oldest_heap' active' cancelling messages store end);

   check_thread_manager ());

 (** user commands **)

 (* kill: move all threads to cancelling *)

 fun kill () = Synchronized.change state

   (fn State {managing_thread, timeout_heap, oldest_heap, active, cancelling, messages, store} =>

     let val formerly_active = map (fn (th, (tb, _, desc)) => (th, (tb, Time.now (), desc))) active

     in make_state

       managing_thread timeout_heap oldest_heap [] (formerly_active @ cancelling) messages store

     end);

 (* ATP info *)

 fun info () =

   let

     val State {active, cancelling, ...} = Synchronized.value state

     fun running_info (_, (birth_time, dead_time, desc)) = "Running: "

         ^ (string_of_int o Time.toSeconds) (Time.- (Time.now (), birth_time))

         ^ " s  --  "

         ^ (string_of_int o Time.toSeconds) (Time.- (dead_time, Time.now ()))

         ^ " s to live:\n" ^ desc

     fun cancelling_info (_, (_, dead_time, desc)) = "Trying to interrupt thread since "

         ^ (string_of_int o Time.toSeconds) (Time.- (Time.now (), dead_time))

         ^ " s:\n" ^ desc

     val running =

       if null active then "No ATPs running."

       else space_implode "\n\n" ("Running ATPs:" :: map running_info active)

     val interrupting =

       if null cancelling then ""

       else space_implode "\n\n"

         ("Trying to interrupt the following ATPs:" :: map cancelling_info cancelling)

   in writeln (running ^ "\n" ^ interrupting) end;

 fun messages opt_limit =

   let

     val limit = the_default message_display_limit opt_limit;

     val State {store = msgs, ...} = Synchronized.value state

     val header = "Recent ATP messages" ^

       (if length msgs <= limit then ":" else " (" ^ string_of_int limit ^ " displayed):");

   in writeln (space_implode "\n\n" (header :: #1 (chop limit msgs))) end;

 (** The Sledgehammer **)

 (* named provers *)

 type prover = int -> (thm * (string * int)) list option ->

   (thm * (string * int)) list option -> string -> int ->

   Proof.context * (thm list * thm) ->

   bool * string * string * string vector * (thm * (string * int)) list

 fun err_dup_prover name = error ("Duplicate prover: " ^ quote name);

 structure Provers = TheoryDataFun

 (

   type T = (prover * stamp) Symtab.table

   val empty = Symtab.empty

   val copy = I

   val extend = I

   fun merge _ tabs : T = Symtab.merge (eq_snd op =) tabs

     handle Symtab.DUP dup => err_dup_prover dup

 );

 fun add_prover name prover thy =

   Provers.map (Symtab.update_new (name, (prover, stamp ()))) thy

     handle Symtab.DUP dup => err_dup_prover dup;

 fun print_provers thy = Pretty.writeln

   (Pretty.strs ("external provers:" :: sort_strings (Symtab.keys (Provers.get thy))));

 fun get_prover name thy = case Symtab.lookup (Provers.get thy) name of

   NONE => NONE

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

 (* start prover thread *)

 fun start_prover name birthtime deadtime i proof_state =

   (case get_prover name (Proof.theory_of proof_state) of

     NONE => warning ("Unknown external prover: " ^ quote name)

   | SOME prover =>

       let

         val (ctxt, (_, goal)) = Proof.get_goal proof_state

         val desc =

           "external prover " ^ quote name ^ " for subgoal " ^ string_of_int i ^ ":\n" ^

             Syntax.string_of_term ctxt (Thm.term_of (Thm.cprem_of goal i))

         val _ = SimpleThread.fork true (fn () =>

           let

             val _ = register birthtime deadtime (Thread.self (), desc)

             val result =

               let val (success, message, _, _, _) =

                 prover (get_timeout ()) NONE NONE name i (Proof.get_goal proof_state)

               in (success, message) end

               handle ResHolClause.TOO_TRIVIAL

                 => (true, "Empty clause: Try this command: " ^ Markup.markup Markup.sendback "apply metis")

               | ERROR msg

                 => (false, "Error: " ^ msg)

             val _ = unregister result (Thread.self ())

           in () end handle Interrupt => ())

       in () end);

 (* sledghammer for first subgoal *)

 fun sledgehammer names proof_state =

   let

     val provers =

       if null names then String.tokens (Symbol.is_ascii_blank o String.str) (get_atps ())

       else names

     val birthtime = Time.now ()

     val deadtime = Time.+ (birthtime, Time.fromSeconds (get_timeout ()))

   in List.app (fn name => start_prover name birthtime deadtime 1 proof_state) provers end;

 (** Isar command syntax **)

 local structure K = OuterKeyword and P = OuterParse in

 val _ =

   OuterSyntax.improper_command "atp_kill" "kill all managed provers" K.diag

     (Scan.succeed (Toplevel.no_timing o Toplevel.imperative kill));

 val _ =

   OuterSyntax.improper_command "atp_info" "print information about managed provers" K.diag

     (Scan.succeed (Toplevel.no_timing o Toplevel.imperative info));

 val _ =

   OuterSyntax.improper_command "atp_messages" "print recent messages issued by managed provers" K.diag

     (Scan.option (P.$$$ "(" |-- P.nat --| P.$$$ ")") >>

       (fn limit => Toplevel.no_timing o Toplevel.imperative (fn () => messages limit)));

 val _ =

   OuterSyntax.improper_command "print_atps" "print external provers" K.diag

     (Scan.succeed (Toplevel.no_timing o Toplevel.unknown_theory o

       Toplevel.keep (print_provers o Toplevel.theory_of)));

 val _ =

   OuterSyntax.command "sledgehammer" "call all automatic theorem provers" K.diag

     (Scan.repeat P.xname >> (fn names => Toplevel.no_timing o Toplevel.unknown_proof o

       Toplevel.keep (sledgehammer names o Toplevel.proof_of)));

 end;

 end;