/*  Part of XPCE --- The SWI-Prolog GUI toolkit

    Author:        Jan Wielemaker and Anjo Anjewierden
    E-mail:        J.Wielemaker@vu.nl
    WWW:           http://www.swi-prolog.org/packages/xpce/
    Copyright (c)  1997-2018, University of Amsterdam
                              VU University Amsterdam
    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,
    INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
    BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
    LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
    LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
    ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
    POSSIBILITY OF SUCH DAMAGE.
*/

:- module(pce_config,
          [ register_config/1,          % +PredicateName
            register_config_type/2,     % +Type, +Attributes
                                        % fetch/set
            get_config/2,               % +Key, -Value
            set_config/2,               % +Key, +Value
            add_config/2,               % +Key, +Value
            del_config/2,               % +Key, +Value
                                        % edit/save/load
            edit_config/1,              % +Graphical
            save_config/1,              % +File
            load_config/1,              % +File
            ensure_loaded_config/1,     % +File
                                        % Type conversion
            config_term_to_object/2,    % ?Term, ?Object
            config_term_to_object/3,    % +Type, ?Term, ?Object
                                        % +Editor interface
            config_attributes/2,        % ?Key, -Attributes
            current_config_type/3       % +Type, -DefModule, -Attributes
          ]).

:- meta_predicate
    register_config(2),
    register_config_type(:, +),
    current_config_type(:, -, -),
    get_config_type(:, -),
    get_config_term(:, -, -),
    get_config(:, -),
    set_config(:, +),
    add_config(:, +),
    del_config(:, +),
    save_config(:),
    load_config(:),
    ensure_loaded_config(:),
    edit_config(:),
    config_attributes(:, -).

:- use_module(library(pce)).
:- use_module(library(broadcast)).
:- require([ is_absolute_file_name/1
           , is_list/1
           , chain_list/2
           , file_directory_name/2
           , forall/2
           , list_to_set/2
           , member/2
           , memberchk/2
           , absolute_file_name/3
           , call/3
           , delete/3
           , maplist/3
           , strip_module/3
           ]).

:- pce_autoload(pce_config_editor,      library(pce_configeditor)).

:- multifile user:file_search_path/2.
:- dynamic   user:file_search_path/2.

user:file_search_path(config, Dir) :-
    get(@pce, application_data, AppDir),
    get(AppDir, path, Dir).

config_version(1).                      % version of the config package

/** <module> XPCE congifuration database

This module deals with saving and   loading application settings such as
preferences and the layout of windows.

@see    library(settings) provides the Prolog equivalent
*/

:- dynamic
    config_type/3,                  % Type, Module, Attributes
    config_db/2,                    % DB, Predicate
    config_store/4.                 % DB, Path, Value, Type


                 /*******************************
                 *           REGISTER           *
                 *******************************/

%!  register_config(:Pred) is det.
%
%   Register  Pred  to  provide  metadata  about  the  configuration
%   handled in the calling module.  Pred   is  called  as call(Pred,
%   Path, Attributes).

register_config(Spec) :-
    strip_module(Spec, Module, Pred),
    (   config_db(Module, Pred)
    ->  true
    ;   asserta(config_db(Module, Pred))
    ).


                 /*******************************
                 *              QUERY           *
                 *******************************/

get_config_type(Key, Type) :-
    strip_module(Key, DB, Path),
    config_db(DB, Pred),
    call(DB:Pred, Path, Attributes),
    memberchk(type(Type), Attributes).

%!  get_config(:Key, -Value) is det.
%
%   Get configuration for Key as Value.

get_config(Key, Value) :-
    strip_module(Key, DB, Path),
    config_store(DB, Path, Value0, Type),
    !,
    config_term_to_object(Type, Value0, Value).
get_config(Key, Value) :-
    config_attribute(Key, default(Default)),
    !,
    (   config_attribute(Key, type(Type))
    ->  strip_module(Key, DB, Path),
        asserta(config_store(DB, Path, Default, Type)),
        config_term_to_object(Type, Default, Value)
    ;   Value = Default
    ).


get_config_term(Key, Term, Type) :-
    strip_module(Key, DB, Path),
    config_store(DB, Path, Term, Type).


                 /*******************************
                 *             MODIFY           *
                 *******************************/

%!  set_config(:Key, +Value) is det.
%
%   Set the configuration parameter Key to   Value.  If the value is
%   modified, a broadcast message set_config(Key, Value) is issued.

set_config(Key, Value) :-
    get_config(Key, Current),
    Value == Current,
    !.
set_config(Key, Value) :-
    strip_module(Key, DB, Path),
    set_config_(DB, Path, Value),
    set_modified(DB),
    broadcast(set_config(Key, Value)).

set_config_(DB, Path, Value) :-         % local version
    (   retract(config_store(DB, Path, _, Type))
    ->  true
    ;   get_config_type(DB:Path, Type)
    ),
    config_term_to_object(Type, TermValue, Value),
    asserta(config_store(DB, Path, TermValue, Type)).

set_config_term(DB, Path, Term, Type) :- % loaded keys
    retractall(config_store(DB, Path, _, _)),
    asserta(config_store(DB, Path, Term, Type)),
    config_term_to_object(Type, Term, Value), % should we broadcast?
    broadcast(set_config(DB:Path, Value)).

set_config_(DB, Path, Value, Type) :-   % local version
    retractall(config_store(DB, Path, _, _)),
    asserta(config_store(DB, Path, Value, Type)).

add_config(Key, Value) :-
    strip_module(Key, DB, Path),
    (   retract(config_store(DB, Path, Set0, Type)),
        is_list(Set0)
    ->  (   delete(Set0, Value, Set1)
        ->  Set = [Value|Set1]
        ;   Set = [Value|Set0]
        )
    ;   retractall(config_store(DB, Path, _, _)), % make sure
        get_config_type(Key, Type),
        Set = [Value]
    ),
    asserta(config_store(DB, Path, Set, Type)),
    set_modified(DB).

del_config(Key, Value) :-
    strip_module(Key, DB, Path),
    config_store(DB, Path, Set0, Type),
    delete(Set0, Value, Set),
    retract(config_store(DB, Path, Set0, Type)),
    !,
    asserta(config_store(DB, Path, Set, Type)),
    set_modified(DB).

set_modified(DB) :-
    config_store(DB, '$modified', true, _),
    !.
set_modified(DB) :-
    asserta(config_store(DB, '$modified', true, bool)).

clear_modified(DB) :-
    retractall(config_store(DB, '$modified', _, _)).


                 /*******************************
                 *            META              *
                 *******************************/

%!  config_attributes(+Key, -Attributes)
%
%   Fetch the (meta) attributes of the given config key.  The special
%   path `config' returns information on the config database itself.
%   The path of the key may be partly instantiated.

config_attributes(Key, Attributes) :-
    strip_module(Key, DB, Path),
    config_db(DB, Pred),
    call(DB:Pred, Path, Attributes).

config_attribute(Key, Attribute) :-
    var(Attribute),
    !,
    config_attributes(Key, Attributes),
    member(Attribute, Attributes).
config_attribute(Key, Attribute) :-
    config_attributes(Key, Attributes),
    memberchk(Attribute, Attributes),
    !.

current_config_path(Key) :-
    strip_module(Key, DB, Path),
    findall(P, config_path(DB, P), Ps0),
    list_to_set(Ps0, Ps),
    member(Path, Ps).

config_path(DB, Path) :-
    config_db(DB, Pred),
    call(DB:Pred, Path, Attributes),
    memberchk(type(_), Attributes).




                 /*******************************
                 *             SAVE             *
                 *******************************/

save_file(Key, File) :-
    is_absolute_file_name(Key),
    !,
    File = Key.
save_file(Key, File) :-
    absolute_file_name(config(Key), File,
                       [ access(write),
                         extensions([cnf]),
                         file_errors(fail)
                       ]),
    !.
save_file(Key, File) :-
    absolute_file_name(config(Key), File,
                       [ extensions([cnf])
                       ]),
    !,
    file_directory_name(File, Dir),
    (   send(directory(Dir), exists)
    ->  send(@pce, report, error, 'Cannot write config directory %s', Dir),
        fail
    ;   send(directory(Dir), make)
    ).


save_config(Spec) :-
    strip_module(Spec, M, Key),
    (   var(Key)
    ->  get_config(M:config/file, Key)
    ;   true
    ),
    save_file(Key, File),
    save_config(File, M).

save_config(File, M) :-
    catch(do_save_config(File, M), E,
          print_message(warning, E)).

do_save_config(File, M) :-
    setup_call_cleanup(
        open(File, write, Fd, [encoding(utf8)]),
        ( save_config_header(Fd, M),
          save_config_body(Fd, M)
        ),
        close(Fd)).

save_config_header(Fd, M) :-
    get(@pce?date, value, Date),
    get(@pce, user, User),
    config_version(Version),
    format(Fd, '/*  XPCE configuration file for "~w"~n', [M]),
    format(Fd, '    Saved ~w by ~w~n', [Date, User]),
    format(Fd, '*/~n~n', []),
    format(Fd, 'configversion(~q).~n', [Version]),
    format(Fd, '[~q].~n~n', [M]),
    format(Fd, '%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%~n', []),
    format(Fd, '% Option lines starting with a `%'' indicate      %~n',[]),
    format(Fd, '% the value is equal to the application default. %~n', []),
    format(Fd, '%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%~n', []).

save_config_body(Fd, M) :-
    forall(current_config_path(M:Path),
           save_config_key(Fd, M:Path)).

save_config_key(Fd, Key) :-
    config_attribute(Key, comment(Comment)),
    nl(Fd),
    (   is_list(Comment)
    ->  format_comment(Comment, Fd)
    ;   format_comment([Comment], Fd)
    ),
    fail.
save_config_key(Fd, Key) :-
    strip_module(Key, _, Path),
    Options = [quoted(true), module(pce)],
    (   get_config_term(Key, Value, _Type),
        (   (   config_attribute(Key, default(Value0))
            ->  Value == Value0
            )
        ->  format(Fd, '%~q = ~t~32|~W.~n', [Path, Value, Options])
        ;   format(Fd, '~q = ~t~32|~W.~n',  [Path, Value, Options])
        ),
        fail
    ;   true
    ).

format_comment([], _).
format_comment([H|T], Fd) :-
    format(Fd, '/* ~w */~n', [H]),
    format_comment(T, Fd).

save_modified_configs :-
    config_db(DB, _Pred),
    get_config(DB:'$modified', true),
    clear_modified(DB),
    get_config(DB:config/file, Key),
    send(@pce, report, status, 'Saving config database %s', Key),
    save_config(DB:_DefaultFile),
    fail.
save_modified_configs.

:- initialization
   send(@pce, exit_message, message(@prolog, save_modified_configs)).


                 /*******************************
                 *             LOAD             *
                 *******************************/

ensure_loaded_config(Spec) :-
    strip_module(Spec, M, _Key),
    config_store(M, _Path, _Value, _Type),
    !.
ensure_loaded_config(Spec) :-
    load_config(Spec).

load_file(Key, File) :-
    is_absolute_file_name(Key),
    !,
    File = Key.
load_file(Key, File) :-
    absolute_file_name(config(Key), File,
                       [ access(read),
                         extensions([cnf]),
                         file_errors(fail)
                       ]).

load_key(_DB, Key) :-
    nonvar(Key),
    !.
load_key(DB, Key) :-
    get_config(DB:config/file, Key),
    !.


load_config(Spec) :-
    strip_module(Spec, M, Key),
    catch(pce_config:load_config(M, Key), E,
          print_message(warning, E)).

load_config(M, Key) :-
    load_key(M, Key),
    load_file(Key, File),
    !,
    setup_call_cleanup(
        ( '$push_input_context'(pce_config),
          open(File, read, Fd, [encoding(utf8)])
        ),
        read_config_file(Fd, _SaveVersion, _SaveModule, Bindings),
        ( close(Fd),
          '$pop_input_context'
        )),
    load_config_keys(M, Bindings),
    set_config_(M, config/file, File, file),
    clear_modified(M).
load_config(M, Key) :-                  % no config file, use defaults
    load_key(M, Key),
    set_config_(M, config/file, Key, file),
    clear_modified(M).              % or not, so we save first time?


read_config_file(Fd, SaveVersion, SaveModule, Bindings) :-
    read(Fd, configversion(SaveVersion)),
    read(Fd, [SaveModule]),
    read_term(Fd, Term, [module(pce)]),
    read_config_file(Term, Fd, Bindings).

read_config_file(end_of_file, _, []) :- !.
read_config_file(Binding, Fd, [Binding|T]) :-
    read_term(Fd, Term, [module(pce)]),
    read_config_file(Term, Fd, T).

load_config_keys(DB, Bindings) :-
    forall(current_config_path(DB:Path),
           load_config_key(DB:Path, Bindings)).

load_config_key(Key, Bindings) :-
    strip_module(Key, DB, Path),
    config_attribute(Key, type(Type)),
    (   member(Path=Value, Bindings)
    *-> set_config_term(DB, Path, Value, Type),
        fail
    ;   config_attribute(Key, default(Value))
    ->  set_config_term(DB, Path, Value, Type)
    ),
    !.
load_config_key(_, _).


                 /*******************************
                 *             EDIT             *
                 *******************************/

edit_config(Spec) :-
    strip_module(Spec, M, Graphical),
    make_config_editor(M, Editor),
    (   object(Graphical),
        send(Graphical, instance_of, visual),
        get(Graphical, frame, Frame)
    ->  send(Editor, transient_for, Frame),
        send(Editor, modal, transient),
        send(Editor, open_centered, Frame?area?center)
    ;   send(Editor, open_centered)
    ).

make_config_editor(M, Editor) :-
    new(Editor, pce_config_editor(M)).


                 /*******************************
                 *             TYPES            *
                 *******************************/

resource(font,          image,  image('16x16/font.png')).
resource(cpalette2,     image,  image('16x16/cpalette2.png')).

builtin_config_type(bool,               [ editor(config_bool_item),
                                          term(map([@off=false, @on=true]))
                                        ]).
builtin_config_type(font,               [ editor(font_item),
                                          term([family, style, points]),
                                          icon(font)
                                        ]).
builtin_config_type(colour,             [ editor(colour_item),
                                          term(if(@arg1?kind == named, name)),
                                          term([@default, red, green, blue])
                                        ]).
builtin_config_type(setof(colour),      [ editor(colour_palette_item),
                                          icon(cpalette2)
                                        ]).
builtin_config_type(image,              [ editor(image_item),
                                          term(if(@arg1?name \== @nil, name)),
                                          term(@arg1?file?absolute_path)
                                        ]).
builtin_config_type(file,               [ editor(file_item)
                                        ]).
builtin_config_type(directory,          [ editor(directory_item)
                                        ]).
builtin_config_type({}(_),              [ editor(config_one_of_item)
                                        ]).
builtin_config_type(_,                  [ editor(config_generic_item)
                                        ]).

register_config_type(TypeSpec, Attributes) :-
    strip_module(TypeSpec, Module, Type),
    (   config_type(Type, Module, Attributes)
    ->  true
    ;   asserta(config_type(Type, Module, Attributes))
    ).

current_config_type(TypeSpec, DefModule, Attributes) :-
    strip_module(TypeSpec, Module, Type),
    (   config_type(Type, Module, Attributes)
    ->  DefModule = Module
    ;   config_type(Type, DefModule, Attributes)
    ).
current_config_type(TypeSpec, pce_config, Attributes) :-
    strip_module(TypeSpec, _Module, Type),
    builtin_config_type(Type, Attributes).

%!  pce_object_type(+Type)
%
%   Succeed if Type denotes an XPCE type

pce_object_type(Var) :-
    var(Var),
    !,
    fail.
pce_object_type(setof(Type)) :-
    !,
    pce_object_type(Type).
pce_object_type(Type) :-
    current_config_type(Type, _, Attributes),
    memberchk(term(_), Attributes).


                 /*******************************
                 *       TERM <-> OBJECT        *
                 *******************************/

config_term_to_object(Type, Term, Object) :-
    pce_object_type(Type),
    !,
    config_term_to_object(Term, Object).
config_term_to_object(_, Value, Value).


config_term_to_object(Term, Object) :-
    nonvar(Object),
    !,
    config_object_to_term(Object, Term).
config_term_to_object(Term, _Object) :-
    var(Term),
    fail.                           % raise error!
config_term_to_object(List, Chain) :-
    is_list(List),
    !,
    maplist(config_term_to_object, List, Objects),
    chain_list(Chain, Objects).
config_term_to_object(Atomic, Atomic) :-
    atomic(Atomic),
    !.
config_term_to_object(Term+Attribute, Object) :-
    !,
    Attribute =.. [AttName, AttTerm],
    config_term_to_object(AttTerm, AttObject),
    config_term_to_object(Term, Object),
    send(Object, AttName, AttObject).
config_term_to_object(Term, Object) :-
    new(Object, Term).

%       Object --> Term

config_object_to_term(@off, false) :- !.
config_object_to_term(@on, true) :- !.
config_object_to_term(@Ref, @Ref) :-
    atom(Ref),
    !.                   % global objects!
config_object_to_term(Chain, List) :-
    send(Chain, instance_of, chain),
    !,
    chain_list(Chain, List0),
    maplist(config_object_to_term, List0, List).
config_object_to_term(Obj, Term) :-
    object(Obj),
    get(Obj, class_name, ClassName),
    term_description(ClassName, Attributes, Condition),
    send(Condition, forward, Obj),
    config_attributes_to_term(Attributes, Obj, Term).
config_object_to_term(Obj, Term) :-
    object(Obj),
    get(Obj, class_name, ClassName),
    term_description(ClassName, Attributes),
    config_attributes_to_term(Attributes, Obj, Term).
config_object_to_term(V, V).

config_attributes_to_term(map(Mapping), Obj, Term) :-
    !,
    memberchk(Obj=Term, Mapping).
config_attributes_to_term(NewAtts+Att, Obj, Term+AttTerm) :-
    !,
    config_attributes_to_term(NewAtts, Obj, Term),
    prolog_value_argument(Obj, Att, AttTermVal),
    AttTerm =.. [Att, AttTermVal].
config_attributes_to_term(Attributes, Obj, Term) :-
    is_list(Attributes),
    !,
    get(Obj, class_name, ClassName),
    maplist(prolog_value_argument(Obj), Attributes, InitArgs),
    Term =.. [ClassName|InitArgs].
config_attributes_to_term(Attribute, Obj, Term) :-
    prolog_value_argument(Obj, Attribute, Term).

                                        % unconditional term descriptions
term_description(Type, TermDescription) :-
    current_config_type(Type, _, Attributes),
    member(term(TermDescription), Attributes),
    \+ TermDescription = if(_,_).
term_description(Type, TermDescription, Condition) :-
    current_config_type(Type, _, Attributes),
    member(term(if(Condition, TermDescription)), Attributes).

prolog_value_argument(Obj, Arg, ArgTerm) :-
    atom(Arg),
    !,
    get(Obj, Arg, V0),
    config_object_to_term(V0, ArgTerm).
prolog_value_argument(Obj, Arg, Value) :-
    functor(Arg, ?, _),
    get(Arg, '_forward', Obj, Value).
prolog_value_argument(_, Arg, Arg).


                 /*******************************
                 *         XREF SUPPORT         *
                 *******************************/

:- multifile
    prolog:called_by/2.

prolog:called_by(register_config(G), [G+2]).
