/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * 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 <http://www.gnu.org/licenses/>.
 *
 */

#include "ultima/shared/std/string.h"
#include "ultima/nuvie/core/nuvie_defs.h"
#include "ultima/nuvie/misc/u6_misc.h"
#include "ultima/nuvie/gui/gui.h"
#include "ultima/nuvie/gui/widgets/gui_widget.h"
#include "ultima/nuvie/gui/gui_scroll_bar.h"
#include "ultima/nuvie/gui/gui_scroller.h"

namespace Ultima {
namespace Nuvie {

GUI_Scroller::GUI_Scroller(int x, int y, int w, int h, uint8 r, uint8 g, uint8 b, uint16 r_height)
	: GUI_Widget(nullptr, x, y, w, h), R(r), G(g), B(b), bg_color(0),
	  row_height(r_height), num_rows(0), disp_offset(0) {
	rows_per_page = h / row_height;
	scroll_bar = new GUI_ScrollBar(area.width() - SCROLLBAR_WIDTH, 0, area.height(), this);

	GUI_Widget::AddWidget(scroll_bar); // we call the GUI_Widget::AddWidget method our method is for scroller container items.
}

/* Map the color to the display */
void GUI_Scroller::SetDisplay(Screen *s) {
	GUI_Widget::SetDisplay(s);
	bg_color = surface->format.RGBToColor(R, G, B);
}

int GUI_Scroller::AddWidget(GUI_Widget *widget) {
	GUI_Widget::AddWidget(widget);
	num_rows++;
	update_viewport(true);

	return 0;
}

void GUI_Scroller::PlaceOnScreen(Screen *s, GUI_DragManager *dm, int x, int y) {
	GUI_Widget::PlaceOnScreen(s, dm, x, y);

	update_viewport(true);
}

void GUI_Scroller::update_viewport(bool update_slider) {
	uint16 i;
	float s_len = 1.0;
	float s_pos = 0.0;

	if (update_slider) {
		if (rows_per_page < num_rows)
			s_len = (float)rows_per_page / (float)num_rows;

		scroll_bar->set_slider_length(s_len);

		if (disp_offset > 0)
			s_pos = (float)disp_offset / (float)num_rows;

		scroll_bar->set_slider_position(s_pos);
	}

	Std::list<GUI_Widget *>::iterator child = children.begin();
	child++; // skip the scroll_bar widget. This is a bit evil.

	for (i = 0; child != children.end(); child++, i++) {
		if (i < disp_offset || i >= disp_offset + rows_per_page)
			(*child)->Hide();
		else {
			(*child)->Move(area.left, area.top + (i - disp_offset) * row_height);
			(*child)->Show();
		}
	}

	return;
}

/* Show the widget  */
void GUI_Scroller:: Display(bool full_redraw) {
	Common::Rect framerect;

	framerect = area;
	framerect.right -= SCROLLBAR_WIDTH;

	SDL_FillRect(surface, &framerect, bg_color);

	DisplayChildren();

// screen->update(area.left,area.top,area.width(),area.height());

	return;
}

GUI_status GUI_Scroller::MouseDown(int x, int y, Events::MouseButton button) {
//grab_focus();

	return GUI_YUM;
}

GUI_status GUI_Scroller::MouseUp(int x, int y, Events::MouseButton button) {

// release_focus();

	return GUI_YUM;
}

GUI_status GUI_Scroller::MouseMotion(int x, int y, uint8 state) {


//GUI::get_gui()->moveWidget(this,dx,dy);
// Redraw();

	return GUI_YUM;
}

GUI_status GUI_Scroller::MouseWheel(sint32 x, sint32 y) {
	if (y > 0)
		move_up();
	else if (y < 0)
		move_down();

	return GUI_YUM;
}

void GUI_Scroller::move_up() {
	if (disp_offset > 0) {
		disp_offset--;
		update_viewport(true);
	}

}

void GUI_Scroller::move_down() {
	if (num_rows - disp_offset > rows_per_page) {
		disp_offset++;
		update_viewport(true);
	}
}

void GUI_Scroller::page_up(bool all) {
	if (disp_offset == 0)
		return;
	if (all)
		disp_offset = 0;
	else {
		for (int i = 0; i < rows_per_page; i++) {
			if (disp_offset > 0)
				disp_offset--;
		}
	}
	update_viewport(true);
}

void GUI_Scroller::page_down(bool all) {
	if (num_rows - disp_offset < rows_per_page)
		return;
	if (all)
		disp_offset = num_rows - rows_per_page;
	else {
		for (int i = 0; i < rows_per_page; i++) {
			if (num_rows - disp_offset > rows_per_page)
				disp_offset++;
		}
	}
	update_viewport(true);
}

void GUI_Scroller::move_percentage(float offset_percentage) {
// DEBUG(0,LEVEL_DEBUGGING,"offset_percentage = %f\n", offset_percentage);

	disp_offset = (int)((float)num_rows * offset_percentage);
	update_viewport(false);

}

GUI_status GUI_Scroller::callback(uint16 msg, GUI_CallBack *caller, void *data) {

	switch (msg) {
	case SCROLLBAR_CB_SLIDER_MOVED :
		move_percentage(*(float *)data);
		break;

	case SCROLLBAR_CB_UP_BUTTON :
		move_up();
		break;

	case SCROLLBAR_CB_DOWN_BUTTON :
		move_down();
		break;
	case SCROLLBAR_CB_PAGE_DOWN:
		page_down();
		break;
	case SCROLLBAR_CB_PAGE_UP:
		page_up();
		break;

	default :
		DEBUG(0, LEVEL_ERROR, "Unhandled callback!\n");
		break;
	}

	return GUI_YUM;
}

} // End of namespace Nuvie
} // End of namespace Ultima