/* 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 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 "engines/metaengine.h"
#include "base/plugins.h"
#include "base/version.h"
#include "common/events.h"
#include "common/system.h"
#include "common/translation.h"
#include "common/util.h"
#include "gui/about.h"
#include "gui/gui-manager.h"
#include "gui/ThemeEval.h"

namespace GUI {

enum {
	kScrollStartDelay = 1500,
	kScrollMillisPerPixel = 60
};

// Every Line should start with a letter followed by a digit. Currently those can be
// (all subject to change)
// Letter:
//   C, L, R     -- set center/left/right alignment
//   A           -- ASCII text to replace the next (latin1) line
// Digit:
//   0 - 2       -- set a custom color:
//                  0 normal text
//                  1 highlighted text
//                  2 disabled text
// TODO: Maybe add a tab/indent feature; that is, make it possible to specify
// an amount by which that line shall be indented (the indent of course would have
// to be considered while performing any word wrapping, too).
//
// TODO: Add different font sizes (for bigger headlines)
// TODO: Allow color change in the middle of a line...

static const char *copyright_text[] = {
"",
"C0""Copyright (C) 2001-2019 The ScummVM Team",
"C0""http://www.scummvm.org",
"",
"C0""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 binary.",
"",
};

static const char *gpl_text[] = {
"",
"C0""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.",
"C0""",
"C0""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.",
"",
"C0""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 "gui/credits.h"

AboutDialog::AboutDialog()
	: Dialog(10, 20, 300, 174),
	_scrollPos(0), _scrollTime(0), _willClose(false) {

	reflowLayout();

	int i;

	for (i = 0; i < 1; i++)
		_lines.push_back("");

	Common::String version("C0""ScummVM ");
	version += gScummVMVersion;
	_lines.push_back(version);

	Common::String date = Common::String::format(_("(built on %s)"), gScummVMBuildDate);
	_lines.push_back("C2" + date);

	for (i = 0; i < ARRAYSIZE(copyright_text); i++)
		addLine(copyright_text[i]);

	Common::String features("C1");
	features += _("Features compiled in:");
	addLine(features.c_str());
	Common::String featureList("C0");
	featureList += gScummVMFeatures;
	addLine(featureList.c_str());

	_lines.push_back("");

	Common::String engines("C1");
	engines += _("Available engines:");
	addLine(engines.c_str());

	const PluginList &plugins = EngineMan.getPlugins();
	PluginList::const_iterator iter = plugins.begin();
	for (; iter != plugins.end(); ++iter) {
		Common::String str;
		str = "C0";
		str += (*iter)->getName();
		addLine(str.c_str());

		str = "C2";
		str += (*iter)->get<MetaEngine>().getOriginalCopyright();
		addLine(str.c_str());

		//addLine("");
	}

	for (i = 0; i < ARRAYSIZE(gpl_text); i++)
		addLine(gpl_text[i]);

	_lines.push_back("");

	for (i = 0; i < ARRAYSIZE(credits); i++)
		addLine(credits[i]);
}

void AboutDialog::addLine(const char *str) {
	if (*str == 0) {
		_lines.push_back("");
	} else {
		Common::String format(str, 2);
		str += 2;

		static Common::String asciiStr;
		if (format[0] == 'A') {
			bool useAscii = false;
#ifdef USE_TRANSLATION
			// We could use TransMan.getCurrentCharset() but rather than compare strings
			// it is easier to use TransMan.getCharsetMapping() (non null in case of non
			// ISO-8859-1 mapping)
			useAscii = (TransMan.getCharsetMapping() != NULL);
#endif
			if (useAscii)
				asciiStr = str;
			return;
		}
		StringArray wrappedLines;
		if (!asciiStr.empty()) {
			g_gui.getFont().wordWrapText(asciiStr, _w - 2 * _xOff, wrappedLines);
			asciiStr.clear();
		} else
			g_gui.getFont().wordWrapText(str, _w - 2 * _xOff, wrappedLines);

		for (StringArray::const_iterator i = wrappedLines.begin(); i != wrappedLines.end(); ++i) {
			_lines.push_back(format + *i);
		}
	}
}


void AboutDialog::open() {
	_scrollTime = g_system->getMillis() + kScrollStartDelay;
	_scrollPos = 0;
	_willClose = false;

	Dialog::open();
}

void AboutDialog::close() {
	Dialog::close();
}

void AboutDialog::drawDialog(DrawLayer layerToDraw) {
	Dialog::drawDialog(layerToDraw);

	setTextDrawableArea(Common::Rect(_x, _y, _x + _w, _y + _h));

	// Draw text
	// TODO: Add a "fade" effect for the top/bottom text lines
	// TODO: Maybe prerender all of the text into another surface,
	//       and then simply compose that over the screen surface
	//       in the right way. Should be even faster...
	const int firstLine = _scrollPos / _lineHeight;
	const int lastLine = MIN((_scrollPos + _h) / _lineHeight + 1, (uint32)_lines.size());
	int y = _y + _yOff - (_scrollPos % _lineHeight);

	for (int line = firstLine; line < lastLine; line++) {
		const char *str = _lines[line].c_str();
		Graphics::TextAlign align = Graphics::kTextAlignCenter;
		ThemeEngine::WidgetStateInfo state = ThemeEngine::kStateEnabled;
		if (*str) {
			switch (str[0]) {
			case 'C':
				align = Graphics::kTextAlignCenter;
				break;
			case 'L':
				align = Graphics::kTextAlignLeft;
				break;
			case 'R':
				align = Graphics::kTextAlignRight;
				break;
			default:
				error("Unknown scroller opcode '%c'", str[0]);
				break;
			}
			switch (str[1]) {
			case '0':
				state = ThemeEngine::kStateEnabled;
				break;
			case '1':
				state = ThemeEngine::kStateHighlight;
				break;
			case '2':
				state = ThemeEngine::kStateDisabled;
				break;
			case '3':
				warning("Need state for color 3");
				// color = g_gui._shadowcolor;
				break;
			case '4':
				warning("Need state for color 4");
				// color = g_gui._bgcolor;
				break;
			default:
				error("Unknown color type '%c'", str[1]);
			}
			str += 2;
		}
		// Trim leading whitespaces if center mode is on
		if (align == Graphics::kTextAlignCenter)
			while (*str && *str == ' ')
				str++;

		if (*str)
			g_gui.theme()->drawText(Common::Rect(_x + _xOff, y, _x + _w - _xOff, y + g_gui.theme()->getFontHeight()),
			                        str, state, align, ThemeEngine::kTextInversionNone, 0, false,
			                        ThemeEngine::kFontStyleBold, ThemeEngine::kFontColorNormal, true, _textDrawableArea);
		y += _lineHeight;
	}
}

void AboutDialog::handleTickle() {
	const uint32 t = g_system->getMillis();
	int scrollOffset = ((int)t - (int)_scrollTime) / kScrollMillisPerPixel;
	if (scrollOffset > 0) {
		int modifiers = g_system->getEventManager()->getModifierState();

		// Scroll faster when shift is pressed
		if (modifiers & Common::KBD_SHIFT)
			scrollOffset *= 4;
		// Reverse scrolling when alt is pressed
		if (modifiers & Common::KBD_ALT)
			scrollOffset *= -1;
		_scrollPos += scrollOffset;
		_scrollTime = t;

		if (_scrollPos < 0) {
			_scrollPos = 0;
		} else if ((uint32)_scrollPos > _lines.size() * _lineHeight) {
			_scrollPos = 0;
			_scrollTime += kScrollStartDelay;
		}
		drawDialog(kDrawLayerForeground);
	}
}

void AboutDialog::handleMouseUp(int x, int y, int button, int clickCount) {
	// Close upon any mouse click
	close();
}

void AboutDialog::handleKeyDown(Common::KeyState state) {
	if (state.ascii)
		_willClose = true;
}

void AboutDialog::handleKeyUp(Common::KeyState state) {
	if (state.ascii && _willClose)
		close();
}

void AboutDialog::reflowLayout() {
	Dialog::reflowLayout();
	int i;
	const int screenW = g_system->getOverlayWidth();
	const int screenH = g_system->getOverlayHeight();

	_xOff = g_gui.xmlEval()->getVar("Globals.About.XOffset", 5);
	_yOff = g_gui.xmlEval()->getVar("Globals.About.YOffset", 5);
	int outerBorder = g_gui.xmlEval()->getVar("Globals.About.OuterBorder");

	_w = screenW - 2 * outerBorder;
	_h = screenH - 2 * outerBorder;

	_lineHeight = g_gui.getFontHeight() + 3;

	// Heuristic to compute 'optimal' dialog width
	int maxW = _w - 2*_xOff;
	_w = 0;
	for (i = 0; i < ARRAYSIZE(credits); i++) {
		int tmp = g_gui.getStringWidth(credits[i]) + 5;
		if (_w < tmp && tmp <= maxW) {
			_w = tmp;
		}
	}
	_w += 2*_xOff;

	// Center the dialog
	_x = (screenW - _w) / 2;
	_y = (screenH - _h) / 2;
}

} // End of namespace GUI