/*
 * tasklist.c - task list widget
 *
 * Copyright © 2008 Julien Danjou <julien@danjou.info>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */

#include "widget.h"
#include "focus.h"
#include "ewmh.h"
#include "tag.h"
#include "common/markup.h"
#include "common/tokenize.h"

extern awesome_t globalconf;

typedef enum
{
    ShowFocus,
    ShowTags,
    ShowAll,
} showclient_t;

/** The tasklist private data structure. */
typedef struct
{
    showclient_t show;
    bool show_icons;
    luaA_function label;
} tasklist_data_t;

struct tasklist_hook_data
{
    draw_context_t *ctx;
    area_t *area;
};

/** Check if a client is visible according to the showclient type paramater.
 * \param c The client.
 * \param screen The screen number.
 * \param show The show parameters.
 * \return True if the client is visible, false otherwise.
 */
static inline bool
tasklist_isvisible(client_t *c, int screen, showclient_t show)
{
    if(c->skip || c->skiptb)
        return false;

    switch(show)
    {
      case ShowAll:
        return (c->screen == screen);
      case ShowTags:
        return client_isvisible(c, screen);
      case ShowFocus:
        return (c == focus_get_current_client(screen));
    }
    return false;
}

/** Called when a markup element is found.
 * \param p The markup parser data.
 * \param elem The element name.
 * \param names The attributes names.
 * \param values The attributes values.
 */
static void
tasklist_markup_on_elem(markup_parser_data_t *p, const char *elem,
                        const char **names, const char **values)
{
    struct tasklist_hook_data *data = p->priv;
    draw_context_t *ctx = data->ctx;

    assert(!a_strcmp(elem, "bg"));
    for(; *names; names++, values++)
        if(!a_strcmp(*names, "color"))
        {
            xcolor_t bg_color;
            xcolor_init(&bg_color, ctx->connection, ctx->phys_screen, *values);
            draw_rectangle(ctx, *data->area, 1.0, true, &bg_color);
            break;
        }
}

/** Draw a tasklist widget.
 * \param ctx The draw context.
 * \param screen The screen number.
 * \param w The widget node we are called from.
 * \param offset The offset to draw at.
 * \param used The already used width.
 * \param p A pointer to the object we're drawing onto.
 */
static int
tasklist_draw(draw_context_t *ctx, int screen,
              widget_node_t *w,
              int offset, int used, void *p __attribute__ ((unused)))
{
    client_t *c;
    tasklist_data_t *d = w->widget->data;
    area_t area;
    const char *text;
    int n = 0, i = 0, box_width = 0, icon_width = 0, box_width_rest = 0;
    netwm_icon_t *icon;
    draw_image_t *image;
    size_t len;

    if(used >= ctx->width)
        return (w->area.width = 0);

    for(c = globalconf.clients; c; c = c->next)
        if(tasklist_isvisible(c, screen, d->show))
            n++;

    if(!n)
        return (w->area.width = 0);

    box_width = (ctx->width - used) / n;
    /* compute how many pixel we left empty */
    box_width_rest = (ctx->width - used) % n;

    w->area.x = widget_calculate_offset(ctx->width,
                                        0, offset, w->widget->align);

    w->area.y = 0;

    for(c = globalconf.clients; c; c = c->next)
        if(tasklist_isvisible(c, screen, d->show))
        {
            icon_width = 0;

            /* push client */
            luaA_client_userdata_new(globalconf.L, c);
            /* call label function with client as argument and wait for one
             * result */
            luaA_dofunction(globalconf.L, d->label, 1, 1);

            if(lua_isstring(globalconf.L, -1))
                text = lua_tolstring(globalconf.L, -1, &len);
            else
                text = NULL;

            lua_pop(globalconf.L, 1);

            if(d->show_icons)
            {
                static char const * const elements[] = { "bg", NULL };
                struct tasklist_hook_data data = { .ctx = ctx, .area = &area };
                markup_parser_data_t pdata =
                {
                    .elements   = elements,
                    .on_element = &tasklist_markup_on_elem,
                    .priv       = &data,
                };

                /* draw a background for icons */
                area.x = w->area.x + box_width * i;
                area.y = w->area.y;
                area.height = ctx->height;
                area.width = box_width;

                /* Actually look for the proper background color, since
                 * otherwise the background statusbar color is used instead */
                markup_parser_data_init(&pdata);
                markup_parse(&pdata, text, a_strlen(text));
                markup_parser_data_wipe(&pdata);

                if((image = draw_image_new(c->icon_path)))
                {
                    icon_width = ((double) ctx->height / (double) image->height) * image->width;
                    draw_image(ctx, w->area.x + box_width * i,
                               w->area.y, ctx->height, image);
                    draw_image_delete(&image);
                }

                if(!icon_width && (icon = ewmh_get_window_icon(c->win)))
                {
                    icon_width = ((double) ctx->height / (double) icon->height)
                        * icon->width;
                    draw_image_from_argb_data(ctx,
                                              w->area.x + box_width * i,
                                              w->area.y,
                                              icon->width, icon->height,
                                              ctx->height, icon->image);
                    p_delete(&icon->image);
                    p_delete(&icon);
                }
            }

            area.x = w->area.x + icon_width + box_width * i;
            area.y = w->area.y;
            area.width = box_width - icon_width;
            area.height = ctx->height;

            /* if we're on last elem, it has the last pixels left */
            if(i == n - 1)
                area.width += box_width_rest;

            draw_text(ctx, globalconf.font, area, text, NULL);

            i++;
        }

    w->area.width = ctx->width - used;
    w->area.height = ctx->height;

    return w->area.width;
}

/** Handle button click on tasklist.
 * \param w The widget node.
 * \param ev The button press event.
 * \param screen The screen where the click was.
 * \param object The object we're onto.
 * \param type The type object.
 */
static void
tasklist_button_press(widget_node_t *w,
                      xcb_button_press_event_t *ev,
                      int screen,
                      void *object,
                      awesome_type_t type)
{
    button_t *b;
    client_t *c;
    tasklist_data_t *d = w->widget->data;
    int n = 0, box_width = 0, i, ci = 0;

    for(c = globalconf.clients; c; c = c->next)
        if(tasklist_isvisible(c, screen, d->show))
            n++;

    if(!n)
        return;

    box_width = w->area.width / n;

    ci = (ev->event_x - w->area.x) / box_width;

    /* found first visible client */
    for(c = globalconf.clients;
        c && !tasklist_isvisible(c, screen, d->show);
        c = c->next);
    /* found ci-th visible client */
    for(i = 0; c ; c = c->next)
        if(tasklist_isvisible(c, screen, d->show))
            if(i++ >= ci)
                break;

    if(c)
        for(b = w->widget->buttons; b; b = b->next)
            if(ev->detail == b->button && CLEANMASK(ev->state) == b->mod && b->fct)
            {
                luaA_pushpointer(globalconf.L, object, type);
                luaA_client_userdata_new(globalconf.L, c);
                luaA_dofunction(globalconf.L, b->fct, 2, 0);
            }
}

/** Index function for tasklist widget.
 * \param L The Lua VM state.
 * \param token The key token.
 * \return The number of elements pushed on stack.
 * \luastack
 * \lfield show_icons Show icons near client title.
 * \lfield show Which windows to show: all, tags, focus.
 * \lfield label Function used to get the string to display as the window title.
 * It gets the client as argument, and must return a string.
 */
static int
luaA_tasklist_index(lua_State *L, awesome_token_t token)
{
    widget_t **widget = luaA_checkudata(L, 1, "widget");
    tasklist_data_t *d = (*widget)->data;

    switch(token)
    {
      case A_TK_SHOW_ICONS:
        lua_pushboolean(L, d->show_icons);
        return 1;
      case A_TK_SHOW:
        switch(d->show)
        {
          case ShowTags:
            lua_pushliteral(L, "tags");
            break;
          case ShowFocus:
            lua_pushliteral(L, "focus");
            break;
          case ShowAll:
            lua_pushliteral(L, "all");
            break;
          default:
            return 0;
        }
        return 1;
      case A_TK_LABEL:
        lua_rawgeti(L, LUA_REGISTRYINDEX, d->label);
        return 1;
      default:
        return 0;
    }
}

/** Newindex function for tasklist widget.
 * \param L The Lua VM state.
 * \param token The key token.
 * \return The number of elements pushed on stack.
 */
static int
luaA_tasklist_newindex(lua_State *L, awesome_token_t token)
{
    size_t len;
    widget_t **widget = luaA_checkudata(L, 1, "widget");
    tasklist_data_t *d = (*widget)->data;
    const char *buf;

    switch(token)
    {
      case A_TK_SHOW_ICONS:
        d->show_icons = luaA_checkboolean(L, 3);
        break;
      case A_TK_SHOW:
        if((buf = luaL_checklstring(L, 3, &len)))
            switch(a_tokenize(buf, len))
            {
              case A_TK_TAGS:
                d->show = ShowTags;
                break;
              case A_TK_FOCUS:
                d->show = ShowFocus;
                break;
              case A_TK_ALL:
                d->show = ShowAll;
                break;
              default:
                break;
            }
        break;
      case A_TK_LABEL:
        luaA_registerfct(L, &d->label);
        break;
      default:
        return 0;
    }

    widget_invalidate_bywidget(*widget);

    return 0;
}

/** Destructor for the tasklist widget.
 * \param widget The widget to destroy.
 */
static void
tasklist_destructor(widget_t *widget)
{
    tasklist_data_t *d = widget->data;
    p_delete(&d);
}

/** Create a new widget tasklist.
 * \param align The widget alignment, which is flex anyway.
 * \return A brand new tasklist widget.
 */
widget_t *
tasklist_new(alignment_t align __attribute__ ((unused)))
{
    widget_t *w;
    tasklist_data_t *d;

    w = p_new(widget_t, 1);
    widget_common_new(w);
    w->draw = tasklist_draw;
    w->button_press = tasklist_button_press;
    w->align = AlignFlex;
    w->index = luaA_tasklist_index;
    w->newindex = luaA_tasklist_newindex;
    w->data = d = p_new(tasklist_data_t, 1);
    w->destructor = tasklist_destructor;
    
    d->show_icons = true;
    d->show = ShowTags;
    d->label = LUA_REFNIL;

    /* Set cache property */
    w->cache_flags = WIDGET_CACHE_CLIENTS;

    return w;
}

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