/*
 * X11 GUI for slide puzzle game
 * Copyright © 2022 Nick Bowler
 *
 * 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 3 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, see <https://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <inttypes.h>
#include <assert.h>
#include <Xm/XmAll.h>

#include "motif.h"
#include "motifgui.h"

#define SPLIT_NUMERATOR    75
#define SPLIT_DENOMINATOR 100

#define MIN(a, b) ((a) < (b) ? (a) : (b))

static void game_configure(Widget w);

static const struct ui_widget {
	uint_least16_t name;
	uint_least16_t subtree;
	WidgetClass *class;
	void (*configure)(Widget w);
} mainwin[] = { MAINWIN_INITIALIZER };

static void
ResizeGameArea(Widget form, XEvent *e, String *args, Cardinal *num_args)
{
	Widget game = XtNameToWidget(form, &tree_strtab[gameArea]);
	Widget goal = XtNameToWidget(form, &tree_strtab[goalArea]);
	Dimension w, h, gamesz, gameborder, goalsz, goalborder;
	int x, y, gap;

	XtVaGetValues(form, XmNwidth, &w, XmNheight, &h, (char *)NULL);
	XtVaGetValues(game, XmNshadowThickness, &gameborder, (char *)NULL);
	XtVaGetValues(goal, XmNshadowThickness, &goalborder,
	                    XmNleftOffset, &gap,
	                    (char *)NULL);

	gamesz = MIN(h, w * SPLIT_NUMERATOR / SPLIT_DENOMINATOR);
	gamesz = 5*( (gamesz - 2*gameborder)/5 ) + 2*gameborder;

	goalsz = MIN(gamesz*3/5, w - gamesz - gap);
	goalsz = 3*( (goalsz - 2*goalborder)/3 ) + 2*goalborder;

	x = (w - gamesz - goalsz - gap) / 2;
	if (x < 2) x = 0;

	y = (h - gamesz) / 2;
	if (y < 3) y = 0;

	XtVaSetValues(game, XmNleftOffset, x, XmNtopOffset, y, (char *)NULL);
	XtVaSetValues(game, XmNwidth, gamesz, XmNheight, gamesz, (char *)NULL);
	XtVaSetValues(goal, XmNwidth, goalsz, XmNheight, goalsz, (char *)NULL);
}

static void game_configure(Widget form)
{
	Widget gamearea = XtNameToWidget(form, &tree_strtab[gameArea]);
	Widget goalarea = XtNameToWidget(form, &tree_strtab[goalArea]);
	XtActionsRec resize_rec;

	assert(gamearea && goalarea);
	XtVaSetValues(form, XmNfractionBase, SPLIT_DENOMINATOR, (char *)NULL);

	XtVaSetValues(gamearea, //XmNrightAttachment, XmATTACH_POSITION,
	                        //XmNrightPosition, SPLIT_NUMERATOR,
	                        XmNleftAttachment, XmATTACH_FORM,
	                        XmNtopAttachment, XmATTACH_FORM,
	                        (char *)NULL);

	XtVaSetValues(goalarea, XmNleftAttachment, XmATTACH_WIDGET,
	                        XmNleftWidget, gamearea,
	                        XmNtopAttachment, XmATTACH_OPPOSITE_WIDGET,
	                        XmNtopWidget, gamearea,
	                        (char *)NULL);

	resize_rec.string = "ResizeGameArea";
	resize_rec.proc = ResizeGameArea;
	XtAppAddActions(XtWidgetToApplicationContext(form), &resize_rec, 1);
	XtOverrideTranslations(form, XtParseTranslationTable(
		"<Configure>: ResizeGameArea()\n"
		"<Map>: ResizeGameArea()\n"
	));
}

static void
construct_widgets(const struct ui_widget *root, Widget parent, unsigned i)
{
	const struct ui_widget *item;

	for (item = &root[i]; item->name; item++) {
		Widget w;

		w = XtCreateWidget(&tree_strtab[item->name], *item->class,
		                   parent, NULL, 0);
		if (item->subtree) {
			construct_widgets(root, w, item->subtree);
		}

		if (item->configure) {
			item->configure(w);
		}

		XtManageChild(w);
	}
}

static void game_resize(Widget w, void *data, void *cb_data)
{
	if (XtIsRealized(w))
		x11_redraw_game(data);
}

static void goal_resize(Widget w, void *data, void *cb_data)
{
	if (XtIsRealized(w))
		x11_redraw_goal(data);
}

static void game_input(Widget w, void *data, void *cb_data)
{
	XmDrawingAreaCallbackStruct *cbs = cb_data;
	XButtonEvent *click = &cbs->event->xbutton;
	struct app_state *state = data;
	Dimension width, height;
	unsigned x = -1, y = -1;

	switch (cbs->event->type) {
	case ButtonPress:
		XtVaGetValues(w, XmNwidth, &width,
		                 XmNheight, &height,
		                 (char *)NULL);
		x = click->x / (width/5);
		y = click->y / (width/5);
	}

	if (x > 4 || y > 4)
		return;

	if (game_do_move(&state->board, x, y) == 0) {
		x11_redraw_game(state);
	}
}

void ui_initialize(struct app_state *state, Widget shell)
{
	construct_widgets(mainwin, shell, 0);

	state->game = XtNameToWidget(shell, "*gameCanvas");
	state->goal = XtNameToWidget(shell, "*goalCanvas");

	XtAddCallback(state->game, XmNresizeCallback, game_resize, state);
	XtAddCallback(state->game, XmNexposeCallback, game_resize, state);
	XtAddCallback(state->game, XmNinputCallback,  game_input,  state);

	XtAddCallback(state->goal, XmNresizeCallback, goal_resize, state);
	XtAddCallback(state->goal, XmNexposeCallback, goal_resize, state);
}