/*  Part of SWI-Prolog

    Author:        Jan Wielemaker
    E-mail:        jan@swi-prolog.org
    WWW:           http://www.swi-prolog.org
    Copyright (c)  2023, SWI-Prolog Solutions b.v.
    All rights reserved.

    Redistribution and use in source and binary forms, with or without
    modification, are permitted provided that the following conditions
    are met:

    1. Redistributions of source code must retain the above copyright
       notice, this list of conditions and the following disclaimer.

    2. Redistributions in binary form must reproduce the above copyright
       notice, this list of conditions and the following disclaimer in
       the documentation and/or other materials provided with the
       distribution.

    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
    LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
    FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
    COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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*/

:- module(prolog_profile,
          [ profile/1,                  % :Goal
            profile/2,                  % :Goal, +Options
            show_profile/1,             % +Options
            profile_data/1,             % -Dict
            profile_procedure_data/2    % :PI, -Data
          ]).
:- autoload(library(error),[must_be/2]).
:- autoload(library(lists), [member/2]).
:- autoload(library(option), [option/3]).
:- autoload(library(pairs), [map_list_to_pairs/3, pairs_values/2]).
:- autoload(library(prolog_code), [predicate_sort_key/2, predicate_label/2]).

:- meta_predicate
    profile(0),
    profile(0, +),
    profile_procedure_data(:, -).

:- set_prolog_flag(generate_debug_info, false).

/** <module> Execution profiler

This module provides a simple frontend on  the execution profiler with a
hook  to  the  GUI  visualiser   for    profiling   results  defined  in
library(swi/pce_profile).
*/

:- multifile
    prolog:show_profile_hook/1.

%!  profile(:Goal).
%!  profile(:Goal, +Options).
%
%   Run once(Goal) under the execution profiler.   If  the (xpce) GUI is
%   enabled this predicate is  hooked   by  library(swi/pce_profile) and
%   results are presented in a gui that enables navigating the call tree
%   and jump to predicate implementations.  Without   the  GUI, a simple
%   textual report is generated. Defined options are:
%
%     * time(Which)
%     Profile `cpu` or `wall` time.  The default is CPU time.
%     * sample_rate(Rate)
%     Samples per second, any numeric value between 1 and 1000
%     * ports(Bool)
%     Specifies ports counted - `true` (all ports), `false` (call
%     port only) or `classic` (all with some errors).
%     Accomodates space/accuracy tradeoff building call tree.
%     * top(N)
%     When generating a textual report, show the top N predicates.
%     * cumulative(Bool)
%     If `true` (default `false`), show cumulative output in
%     a textual report.
%
%   @tbd The textual input reflects only part of the information.
%   @see show_coverage/2 from library(test_cover).

profile(Goal) :-
    profile(Goal, []).

profile(Goal0, Options) :-
    option(time(Which), Options, cpu),
    time_name(Which, How),
    option(ports(Ports), Options, classic),
    must_be(oneof([true,false,classic]),Ports),
    option(sample_rate(Rate), Options, 200),
    must_be(between(1.0,1000), Rate),
    expand_goal(Goal0, Goal),
    call_cleanup('$profile'(Goal, How, Ports, Rate),
                 prolog_statistics:show_profile(Options)).

time_name(cpu,      cputime)  :- !.
time_name(wall,     walltime) :- !.
time_name(cputime,  cputime)  :- !.
time_name(walltime, walltime) :- !.
time_name(Time, _) :-
    must_be(oneof([cpu,wall]), Time).

%!  show_profile(+Options)
%
%   Display last collected profiling data.  Options are
%
%     * top(N)
%     When generating a textual report, show the top N predicates.
%     * cumulative(Bool)
%     If =true= (default =false=), show cumulative output in
%     a textual report.

show_profile(N) :-
    integer(N),
    !,
    show_profile([top(N)]).
show_profile(Options) :-
    profiler(Old, false),
    show_profile_(Options),
    profiler(_, Old).

show_profile_(Options) :-
    prolog:show_profile_hook(Options),
    !.
show_profile_(Options) :-
    prof_statistics(Stat),
    sort_on(Options, SortKey),
    findall(Node, profile_procedure_data(_:_, Node), Nodes),
    sort_prof_nodes(SortKey, Nodes, Sorted),
    format('~`=t~69|~n'),
    format('Total time: ~3f seconds~n', [Stat.time]),
    format('~`=t~69|~n'),
    format('~w~t~w =~45|~t~w~60|~t~w~69|~n',
           [ 'Predicate', 'Box Entries', 'Calls+Redos', 'Time'
           ]),
    format('~`=t~69|~n'),
    option(top(N), Options, 25),
    show_plain(Sorted, N, Stat, SortKey).

sort_on(Options, ticks_self) :-
    option(cumulative(false), Options, false),
    !.
sort_on(_, ticks).

sort_prof_nodes(ticks, Nodes, Sorted) :-
    !,
    map_list_to_pairs(key_ticks, Nodes, Keyed),
    sort(1, >=, Keyed, KeySorted),
    pairs_values(KeySorted, Sorted).
sort_prof_nodes(Key, Nodes, Sorted) :-
    sort(Key, >=, Nodes, Sorted).

key_ticks(Node, Ticks) :-
    Ticks is Node.ticks_self + Node.ticks_siblings.

show_plain([], _, _, _).
show_plain(_, 0, _, _) :- !.
show_plain([H|T], N, Stat, Key) :-
    show_plain(H, Stat, Key),
    N2 is N - 1,
    show_plain(T, N2, Stat, Key).

show_plain(Node, Stat, Key) :-
    value(label,                       Node, Pred),
    value(call,                        Node, Call),
    value(redo,                        Node, Redo),
    value(time(Key, percentage, Stat), Node, Percent),
    IntPercent is round(Percent*10),
    Entry is Call + Redo,
    format('~w~t~D =~45|~t~D+~55|~D ~t~1d%~69|~n',
           [Pred, Entry, Call, Redo, IntPercent]).


                 /*******************************
                 *         DATA GATHERING       *
                 *******************************/

%!  profile_data(-Data) is det.
%
%   Gather all relevant data from profiler. This predicate may be called
%   while profiling is active  in  which   case  it  is  suspended while
%   collecting the data. Data is a dict providing the following fields:
%
%     - summary:Dict
%       Overall statistics providing
%       - samples:Count:
%         Times the statistical profiler was called
%       - ticks:Count
%         Virtual ticks during profiling
%       - accounting:Count
%         Tick spent on accounting
%       - time:Seconds
%         Total time sampled
%       - nodes:Count
%         Nodes in the call graph.
%       - sample_period: MicroSeconds
%         Same interval timer period in micro seconds
%       - ports: Ports
%         One of `true`, `false` or `classic`
%     - nodes
%       List of nodes.  Each node provides:
%       - predicate:PredicateIndicator
%       - ticks_self:Count
%       - ticks_siblings:Count
%       - call:Count
%       - redo:Count
%       - exit:Count
%       - callers:list_of(Relative)
%       - callees:list_of(Relative)
%
%    _Relative_ is a term of the shape below that represents a caller or
%    callee. Future versions are likely to use a dict instead.
%
%        node(PredicateIndicator, CycleID, Ticks, TicksSiblings,
%             Calls, Redos, Exits)

profile_data(Data) :-
    setup_call_cleanup(
        profiler(Old, false),
        profile_data_(Data),
        profiler(_, Old)).

profile_data_(profile{summary:Summary, nodes:Nodes}) :-
    prof_statistics(Summary),
    findall(Node, profile_procedure_data(_:_, Node), Nodes).

%!  prof_statistics(-Node) is det.
%
%   Get overall statistics
%
%   @param Node     term of the format prof(Ticks, Account, Time, Nodes)

prof_statistics(summary{samples:Samples, ticks:Ticks,
                        accounting:Account, time:Time,
                        nodes:Nodes,
                        sample_period: Period,
                        ports: Ports
                       }) :-
    '$prof_statistics'(Samples, Ticks, Account, Time, Nodes, Period, Ports).

%!  profile_procedure_data(?Pred, -Data:dict) is nondet.
%
%   Collect data for Pred. If Pred is   unbound  data for each predicate
%   that has profile data available is   returned.  Data is described in
%   profile_data/1 as an element of the `nodes` key.

profile_procedure_data(Pred, Node) :-
    Node = node{predicate:Pred,
                ticks_self:TicksSelf, ticks_siblings:TicksSiblings,
                call:Call, redo:Redo, exit:Exit,
                callers:Parents, callees:Siblings},
    (   specified(Pred)
    ->  true
    ;   profiled_predicates(Preds),
        member(Pred, Preds)
    ),
    '$prof_procedure_data'(Pred,
                           TicksSelf, TicksSiblings,
                           Call, Redo, Exit,
                           Parents, Siblings).

specified(Module:Head) :-
    atom(Module),
    callable(Head).

profiled_predicates(Preds) :-
    setof(Pred, prof_impl(Pred), Preds).

prof_impl(Pred) :-
    prof_node_id(Node),
    node_id_pred(Node, Pred).

prof_node_id(N) :-
    prof_node_id_below(N, -).

prof_node_id_below(N, Root) :-
    '$prof_sibling_of'(N0, Root),
    (   N = N0
    ;   prof_node_id_below(N, N0)
    ).

node_id_pred(Node, Pred) :-
    '$prof_node'(Node, Pred, _Calls, _Redos, _Exits, _Recur,
                 _Ticks, _SiblingTicks).

%!  value(+Key, +NodeData, -Value)
%
%   Obtain possible computed attributes from NodeData.

value(name, Data, Name) :-
    !,
    predicate_sort_key(Data.predicate, Name).
value(label, Data, Label) :-
    !,
    predicate_label(Data.predicate, Label).
value(ticks, Data, Ticks) :-
    !,
    Ticks is Data.ticks_self + Data.ticks_siblings.
value(time(Key, percentage, Stat), Data, Percent) :-
    !,
    value(Key, Data, Ticks),
    Total = Stat.ticks,
    Account = Stat.accounting,
    (   Total-Account > 0
    ->  Percent is 100 * (Ticks/(Total-Account))
    ;   Percent is 0.0
    ).
value(Name, Data, Value) :-
    Value = Data.Name.