/* ScummVM - Scumm Interpreter
 * Copyright (C) 2001  Ludvig Strigeus
 * Copyright (C) 2001/2002 The ScummVM project
 *
 * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 * $Header$
 *
 */

#include "sdl-common.h"
#include "common/scaler.h"
#include "common/util.h"
#include "common/engine.h"	// Only #included for error() and warning()

class OSystem_SDL : public OSystem_SDL_Common {
public:
	OSystem_SDL();

	// Set colors of the palette
	void set_palette(const byte *colors, uint start, uint num);

	// Update the dirty areas of the screen
	void update_screen();

	// Set a parameter
	uint32 property(int param, Property *value);

protected:
	SDL_Surface *_hwscreen;    // hardware screen

	ScalerProc *_scaler_proc;

	virtual void load_gfx_mode();
	virtual void unload_gfx_mode();
	void hotswap_gfx_mode();
};

OSystem_SDL_Common *OSystem_SDL_Common::create() {
	return new OSystem_SDL();
}

OSystem_SDL::OSystem_SDL()
	 : _hwscreen(0), _scaler_proc(0)
{
}

void OSystem_SDL::set_palette(const byte *colors, uint start, uint num) {
	const byte *b = colors;
	uint i;
	SDL_Color *base = _currentPalette + start;
	for(i = 0; i < num; i++) {
		base[i].r = b[0];
		base[i].g = b[1];
		base[i].b = b[2];
		b += 4;
	}

	if (start < _paletteDirtyStart)
		_paletteDirtyStart = start;

	if (start + num > _paletteDirtyEnd)
		_paletteDirtyEnd = start + num;
}

void OSystem_SDL::load_gfx_mode() {
	_forceFull = true;
	_mode_flags = DF_UPDATE_EXPAND_1_PIXEL;

	_tmpscreen = NULL;
	_tmpScreenWidth = (_screenWidth + 3);
	
	switch(_mode) {
	case GFX_2XSAI:
		_scaleFactor = 2;
		_scaler_proc = _2xSaI;
		break;
	case GFX_SUPER2XSAI:
		_scaleFactor = 2;
		_scaler_proc = Super2xSaI;
		break;
	case GFX_SUPEREAGLE:
		_scaleFactor = 2;
		_scaler_proc = SuperEagle;
		break;
	case GFX_ADVMAME2X:
		_scaleFactor = 2;
		_scaler_proc = AdvMame2x;
		break;
	case GFX_TV2X:
		_scaleFactor = 2;
		_scaler_proc = TV2x;
		break;
	case GFX_DOTMATRIX:
		_scaleFactor = 2;
		_scaler_proc = DotMatrix;
		break;

	case GFX_DOUBLESIZE:
		_scaleFactor = 2;
		_scaler_proc = Normal2x;
		break;

	case GFX_TRIPLESIZE:
		if (_full_screen) {
			warning("full screen in useless in triplesize mode, reverting to normal mode");
			goto normal_mode;
		}
		_scaleFactor = 3;
		_scaler_proc = Normal3x;
		break;

	case GFX_NORMAL:
normal_mode:;
		_scaleFactor = 1;
		_scaler_proc = Normal1x;
		break;
	default:
		error("unknown gfx mode");
		_scaleFactor = 1;
		_scaler_proc = NULL;
	}

	//
	// Create the surface that contains the 8 bit game data
	//
	_screen = SDL_CreateRGBSurface(SDL_SWSURFACE, _screenWidth, _screenHeight, 8, 0, 0, 0, 0);
	if (_screen == NULL)
		error("_screen failed");

	//
	// Create the surface that contains the scaled graphics in 16 bit mode
	//
	_hwscreen = SDL_SetVideoMode(_screenWidth * _scaleFactor, _screenHeight * _scaleFactor, 16, 
		_full_screen ? (SDL_FULLSCREEN|SDL_SWSURFACE) : SDL_SWSURFACE
	);
	if (_hwscreen == NULL)
		error("_hwscreen failed");
	
	//
	// Create the surface used for the graphics in 16 bit before scaling, and also the overlay
	//

	// Distinguish 555 and 565 mode
	if (_hwscreen->format->Rmask == 0x7C00)
		Init_2xSaI(555);
	else
		Init_2xSaI(565);
	
	// Need some extra bytes around when using 2xSaI
	uint16 *tmp_screen = (uint16 *)calloc(_tmpScreenWidth * (_screenHeight + 3), sizeof(uint16));
	_tmpscreen = SDL_CreateRGBSurfaceFrom(tmp_screen,
						_tmpScreenWidth, _screenHeight + 3, 16, _tmpScreenWidth * 2,
						_hwscreen->format->Rmask,
						_hwscreen->format->Gmask,
						_hwscreen->format->Bmask,
						_hwscreen->format->Amask);

	if (_tmpscreen == NULL)
		error("_tmpscreen failed");

	// keyboard cursor control, some other better place for it?
	km.x_max = _screenWidth * _scaleFactor - 1;
	km.y_max = _screenHeight * _scaleFactor - 1;
	km.delay_time = 25;
	km.last_time = 0;
}

void OSystem_SDL::unload_gfx_mode() {
	if (_screen) {
		SDL_FreeSurface(_screen);
		_screen = NULL; 
	}

	if (_hwscreen) {
		SDL_FreeSurface(_hwscreen); 
		_hwscreen = NULL;
	}
	
	if (_tmpscreen) {
		free(_tmpscreen->pixels);
		SDL_FreeSurface(_tmpscreen);
		_tmpscreen = NULL;
	}
}

void OSystem_SDL::hotswap_gfx_mode() {
	if (!_screen)
		return;

	// Keep around the old _screen & _tmpscreen so we can restore the screen data
	// after the mode switch.
	SDL_Surface *old_screen = _screen;
	SDL_Surface *old_tmpscreen = _tmpscreen;

	// Release the HW screen surface
	SDL_FreeSurface(_hwscreen); 

	// Setup the new GFX mode
	load_gfx_mode();

	// reset palette
	SDL_SetColors(_screen, _currentPalette, 0, 256);

	// Restore old screen content
	SDL_BlitSurface(old_screen, NULL, _screen, NULL);
	SDL_BlitSurface(old_tmpscreen, NULL, _tmpscreen, NULL);
	
	// Free the old surfaces
	SDL_FreeSurface(old_screen);
	free(old_tmpscreen->pixels);
	SDL_FreeSurface(old_tmpscreen);

	// Finally, blit everything to the screen
	update_screen();
}

void OSystem_SDL::update_screen() {
	assert(_hwscreen != NULL);

	// If the shake position changed, fill the dirty area with blackness
	if (_currentShakePos != _newShakePos) {
		SDL_Rect blackrect = {0, 0, _screenWidth * _scaleFactor, _newShakePos * _scaleFactor};
		SDL_FillRect(_hwscreen, &blackrect, 0);

		_currentShakePos = _newShakePos;

		_forceFull = true;
	}

	// Make sure the mouse is drawn, if it should be drawn.
	draw_mouse();
	
	// Check whether the palette was changed in the meantime and update the
	// screen surface accordingly. 
	if (_paletteDirtyEnd != 0) {
		SDL_SetColors(_screen, _currentPalette + _paletteDirtyStart, 
			_paletteDirtyStart,
			_paletteDirtyEnd - _paletteDirtyStart);
		
		_paletteDirtyEnd = 0;

		_forceFull = true;
	}

	// Force a full redraw if requested
	if (_forceFull) {
		_num_dirty_rects = 1;

		_dirty_rect_list[0].x = 0;
		_dirty_rect_list[0].y = 0;
		_dirty_rect_list[0].w = _screenWidth;
		_dirty_rect_list[0].h = _screenHeight;
	}

	// Only draw anything if necessary
	if (_num_dirty_rects > 0) {

		SDL_Rect *r; 
		uint32 srcPitch, dstPitch;
		SDL_Rect *last_rect = _dirty_rect_list + _num_dirty_rects;

		// Convert appropriate parts of the 8bpp image into 16bpp
		if (!_overlayVisible) {
			SDL_Rect dst;
			for(r = _dirty_rect_list; r != last_rect; ++r) {
				dst = *r;
				dst.x++;	// Shift rect by one since 2xSai needs to acces the data around
				dst.y++;	// any pixel to scale it, and we want to avoid mem access crashes.
				if (SDL_BlitSurface(_screen, r, _tmpscreen, &dst) != 0)
					error("SDL_BlitSurface failed: %s", SDL_GetError());
			}
		}

		SDL_LockSurface(_tmpscreen);
		SDL_LockSurface(_hwscreen);
	
		srcPitch = _tmpscreen->pitch;
		dstPitch = _hwscreen->pitch;
	
		for(r = _dirty_rect_list; r != last_rect; ++r) {
			register int dst_y = r->y + _currentShakePos;
			register int dst_h = 0;
			if (dst_y < _screenHeight) {
				dst_h = r->h;
				if (dst_h > _screenHeight - dst_y)
					dst_h = _screenHeight - dst_y;

				dst_y *= _scaleFactor;

				_scaler_proc((byte *)_tmpscreen->pixels + (r->x * 2 + 2) + (r->y + 1) * srcPitch, srcPitch, NULL, 
					(byte *)_hwscreen->pixels + r->x * 2 * _scaleFactor + dst_y * dstPitch, dstPitch, r->w, dst_h);
			}
			
			r->x *= _scaleFactor;
			r->y = dst_y;
			r->w *= _scaleFactor;
			r->h = dst_h * _scaleFactor;
		}
		
		SDL_UnlockSurface(_tmpscreen);
		SDL_UnlockSurface(_hwscreen);

		// Readjust the dirty rect list in case we are doing a full update.
		// This is necessary if shaking is active.
		if (_forceFull) {
			_dirty_rect_list[0].y = 0;
			_dirty_rect_list[0].h = _screenHeight * _scaleFactor;
		}

		// Finally, blit all our changes to the screen
		SDL_UpdateRects(_hwscreen, _num_dirty_rects, _dirty_rect_list);
	}

	_num_dirty_rects = 0;
	_forceFull = false;
}

uint32 OSystem_SDL::property(int param, Property *value) {
	if (param == PROP_TOGGLE_FULLSCREEN) {
		assert(_hwscreen != 0);
		_full_screen ^= true;
#ifdef MACOSX
		// On OS X, SDL_WM_ToggleFullScreen is currently not implemented. Worse,
		// it still always returns -1. So we simply don't call it at all and
		// use hotswap_gfx_mode() directly to switch to fullscreen mode.
		hotswap_gfx_mode();
#else
		if (!SDL_WM_ToggleFullScreen(_hwscreen)) {
			// if ToggleFullScreen fails, achieve the same effect with hotswap gfx mode
			hotswap_gfx_mode();
		}
#endif
		return 1;
	} else if (param == PROP_SET_GFX_MODE) {
		if (value->gfx_mode >= 9)
			return 0;

		_mode = value->gfx_mode;
		hotswap_gfx_mode();

		return 1;
	}

	return OSystem_SDL_Common::property(param, value);
}