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

    Author:        Jan Wielemaker and Anjo Anjewierden
    E-mail:        jan@swi.psy.uva.nl
    WWW:           http://www.swi.psy.uva.nl/projects/xpce/
    Copyright (c)  1999-2011, University of 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_tool_button, []).
:- use_module(library(pce)).
:- use_module(library(help_message)).
:- use_module(library(imageops)).
:- require([ default/3
           ]).

/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
This library module defines  three   classes:  tool_bar, tool_button and
tool_status_button. It is intended for defining   rows  of buttons, also
called tool-bars. Each button represents an   action  on the `client' of
the tool_bar.

Below is a typical example:

resource(printer,       image,  image('16x16/print.png')).
resource(floppy,        image,  image('16x16/save.png')).

:- pce_begin_class(myapp, frame).

initialise(MyApp) :->
        send_super(MyApp, initialise, 'My application'),
        send(F, append, new(D, tool_dialog(MyApp))),
        send_list(TB, append,
                  [ tool_button(load,
                                resource(floppy),
                                load),
                    gap,                % skip a little
                    tool_button(print,
                                resource(printer),
                                print)
                  ]),
        ...

print(MyApp) :->
        <Print the current document>

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

:- pce_begin_class(tool_bar, dialog_group,
                   "Row of buttons").

variable(orientation,   {horizontal,vertical},  get,  "Stacking direction").
variable(client,        object*,                both, "Receiving object").

initialise(BG, Client:[object]*, Orientation:[{horizontal,vertical}]) :->
    default(Client, @nil, C),
    default(Orientation, horizontal, O),
    send(BG, send_super, initialise, @default, group),
    send(BG, slot, client, C),
    send(BG, slot, orientation, O),
    send(BG, gap, size(0,0)).

append(BG, B:'tool_button|{gap}') :->
    "Append button or gap"::
    (   get(BG, orientation, horizontal)
    ->  Where = right
    ;   Where = next_row
    ),
    (   B == gap
    ->  What = graphical(0, 0, 5, 5)
    ;   What = B
    ),
    send(BG, send_super, append, What, Where).

activate(BG) :->
    "Update activation of member buttons"::
    send(BG?graphicals, for_some,
         if(message(@arg1, has_send_method, activate),
            message(@arg1, activate))).

reference(BG, Ref:point) :<-
    "Reference is at the baseline"::
    get(BG, height, H),
    new(Ref, point(0, H)).

compute(BG) :->
    "Make all buttons the same size"::
    (   get(BG, request_compute, @nil)
    ->  true
    ;   new(S, size(0,0)),
        send(BG?graphicals, for_all,
             if(message(@arg1, instance_of, button),
                message(S, union, @arg1?size))),
        send(BG?graphicals, for_all,
             if(message(@arg1, instance_of, button),
                message(@arg1, size, S))),
        send_super(BG, compute)
    ).

:- pce_end_class.

:- pce_begin_class(tool_button(client, name), button,
                   "Button for a tool_bar").

variable(condition,     code*,       get, "Condition for activation").

initialise(TB,
           Action:action='name|code',
           Label:label='name|image',
           Balloon:balloon=[name|string],
           Condition:condition=[code]*,
           Name:name=[name]) :->
    default(Condition, @nil, Cond),
    make_label(Label, Lbl),
    make_name(Action, Name, ButtonName),
    make_message(Action, Msg),
    send(TB, send_super, initialise, ButtonName, Msg),
    send(TB, label, Lbl),
    send(TB, slot, condition, Cond),
    (   Balloon == @default
    ->  true
    ;   atom(Balloon)
    ->  get(Balloon, label_name, Text),
        send(TB, help_message, tag, Text)
    ;   send(TB, help_message, tag, Balloon)
    ).

client(TB, Client:object) :<-
    get(TB, device, Dev),
    get(Dev, client, Client).

make_message(Name, @default) :-
    atomic(Name),
    !.
make_message(Code, Code).


make_name(Action, @default, Name) :-
    !,
    make_name(Action, Name).
make_name(_, Name, Name).

make_name(Name, Name) :-
    atomic(Name),
    !.
make_name(Code, Name) :-
    send(Code, instance_of, message),
    get(Code, selector, Name),
    atom(Name),
    !.
make_name(_, 'tool_button').


make_label(Image, Image) :-
    send(Image, instance_of, image),
    !.
make_label(Name, Image) :-
    pce_catch_error(cannot_find_file, new(Image, image(Name))),
    !.
make_label(Name, Image) :-
    new(T, text(Name, left, small)),
    get(T, size, size(W, H)),
    new(I0, image(@nil, W, H)),
    send(I0, draw_in, T),
    get(I0, scale, size(16,16), Image),
    free(T),
    free(I0).


forward(TB) :->
    "Send action to <-client"::
    get(TB, message, Msg),
    (   Msg == @default
    ->  get(TB, name, Selector),
        get(TB, client, Client),
        send(Client, Selector)
    ;   send(Msg, execute)
    ).


activate(TB) :->
    "Update the activation using <-condition"::
    (   get(TB, condition, Cond),
        Cond \== @nil
    ->  (   get(TB, client, Client),
            send(Cond, forward, Client)
        ->  send(TB, active, @on)
        ;   send(TB, active, @off)
        )
    ).

active(TB, Val:bool) :->
    "(de)activate the menu-item"::
    send(TB, send_super, active, Val),
    (   get(TB, label, Image),
        send(Image, instance_of, image)
    ->  get(Image, active, Val, Activated),
        send(TB, label, Activated)
    ;   true
    ).

:- pce_end_class.

:- pce_begin_class(tool_status_button, tool_button,
                   "A tool button representing two states").

variable(value,         bool := @off,   get, "Current value").

execute(TB) :->
    "Switch status and send message"::
    get(TB, value, Value),
    get(Value, negate, NewValue),
    send(TB, value, NewValue),
    get(TB, message, Message),
    (   Message == @default
    ->  get(TB, client, Client),
        get(TB, name, Selector),
        send(Client, Selector, NewValue)
    ;   Message == @nil
    ->  true
    ;   send(Message, forward, NewValue)
    ).


value(TB, Value:bool) :->
    (   get(TB, value, Value)
    ->  true
    ;   send(TB, slot, value, Value),
        (   Value == @on
        ->  send(TB, status, execute)
        ;   send(TB, status, inactive)
        )
    ).


reset(TB) :->
    "Smooth handling of abort"::
    (   get(TB, value, @off)
    ->  send(TB, status, inactive)
    ;   send(TB, status, execute)
    ).

:- pce_end_class(tool_status_button).


                 /*******************************
                 *            DIALOG            *
                 *******************************/

:- pce_begin_class(tool_dialog, dialog,
                   "Dialog for menu-bar and toolbar").

variable(client,        [object],       get, "The client").

initialise(TD, Client:[object]) :->
    "Refine layout"::
    send_super(TD, initialise),
    send(TD, slot, client, Client),
    send(TD, pen, 0),
    send(TD, border, size(0, 2)).


menu_bar(TD, Create:[bool], MB:menu_bar) :<-
    "Get (or create) the menu_bar"::
    (   get(TD, member, menu_bar, MB)
    ->  true
    ;   Create == @on
    ->  (   get(TD, tool_bar, TB)
        ->  send(new(MB, menu_bar), above, TB)
        ;   send(TD, append, new(MB, menu_bar))
        )
    ).

tool_bar(TD, Create:[bool], TB:tool_bar) :<-
    "Get (or create) the tool_bar"::
    (   get(TD, member, tool_bar, TB)
    ->  true
    ;   Create == @on
    ->  (   get(TD, client, Client),
            Client \== @default
        ->  true
        ;   get(TD, frame, Client)
        ),
        (   get(TD, menu_bar, MB)
        ->  send(new(TB, tool_bar(Client)), below, MB)
        ;   send(TD, append, new(TB, tool_bar(Client)))
        )
    ).


popup(TD, Name:name, Create:[bool], Popup:popup) :<-
    "Find named popup or create it"::
    get(TD, menu_bar, Create, MB),
    (   get(MB, member, Name, Popup)
    ->  true
    ;   Create == @on
    ->  send(MB, append, new(Popup, popup(Name))),
        send(Popup, message, message(TD, action, @arg1))
    ).


append(TD,
       B:'popup|menu_item|tool_button|graphical|{gap}',
       Where:where=[name], Before:before=[any]) :->
    "Append buttons or popup for manu-bar"::
    (   send(B, instance_of, popup)
    ->  get(TD, menu_bar, @on, MB),
        send(MB, append, B),
        (   get(B, message, @default)
        ->  send(B, message, message(TD, action, @arg1))
        ;   true
        )
    ;   send(B, instance_of, menu_item)
    ->  get(TD, popup, Where, @on, Popup),
        send(Popup, insert_before, B, Before)
    ;   (   send(B, instance_of, tool_button)
        ;   B == gap
        )
    ->  get(TD, tool_bar, @on, TB),
        send(TB, append, B)
    ;   send_super(TD, append, B, Where)
    ).

action(TD, Action:name) :->
    "Forward popup-action to <-client"::
    (   get(TD, client, Client),
        Client \== @default
    ->  send(Client, Action)
    ;   send(TD, report, error, 'No client for posting action')
    ).

:- pce_end_class(tool_dialog).

