/*************************************************************************
** TpicSpecialHandler.cpp                                               **
**                                                                      **
** This file is part of dvisvgm -- the DVI to SVG converter             **
** Copyright (C) 2005-2013 Martin Gieseking <martin.gieseking@uos.de>   **
**                                                                      **
** 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 <cmath>
#include <cstring>
#include <sstream>
#include "Color.h"
#include "InputBuffer.h"
#include "InputReader.h"
#include "SpecialActions.h"
#include "TpicSpecialHandler.h"
#include "XMLNode.h"
#include "XMLString.h"
#include "types.h"

using namespace std;


TpicSpecialHandler::TpicSpecialHandler () {
	reset();
}


void TpicSpecialHandler::dviEndPage (unsigned pageno) {
	reset();
}


void TpicSpecialHandler::reset () {
	_points.clear();
	_penwidth = 1.0;
	_fill = -1.0; // no fill
}


/** Creates SVG elements that draw lines through the recorded points.
 *  @param[in] stroke if true, the (out)line is drawn (in black)
 *  @param[in] fill if true, enclosed area is filled with current color
 *  @param[in] ddist dash/dot distance of line in TeX point units
 *                   (0:solid line, >0:dashed line, <0:dotted line) */
void TpicSpecialHandler::drawLines (bool stroke, bool fill, double ddist, SpecialActions *actions) {
	if (actions && !_points.empty()) {
		XMLElementNode *elem=0;
		if (_points.size() == 1) {
			const DPair &p = _points.back();
			elem = new XMLElementNode("circle");
			elem->addAttribute("cx", p.x()+actions->getX());
			elem->addAttribute("cy", p.y()+actions->getY());
			elem->addAttribute("r", _penwidth/2.0);
			actions->embed(p, _penwidth/2.0);
		}
		else {
			if (_points.size() == 2 || (!fill && _points.front() != _points.back())) {
				elem = new XMLElementNode("polyline");
				elem->addAttribute("fill", "none");
				elem->addAttribute("stroke-linecap", "round");
			}
			else {
				if (_points.front() == _points.back())
					_points.pop_back();
				if (_fill < 0)
					_fill = 1;
				Color color = actions->getColor();
				color *= _fill;
				elem = new XMLElementNode("polygon");
				elem->addAttribute("fill", fill ? color.rgbString() : "none");
			}
			ostringstream oss;
			FORALL(_points, vector<DPair>::iterator, it) {
				if (it != _points.begin())
					oss << ' ';
				double x = it->x()+actions->getX();
			  	double y = it->y()+actions->getY();
				oss << XMLString(x) << ',' << XMLString(y);
				actions->embed(DPair(x, y));
			}
			elem->addAttribute("points", oss.str());
			if (stroke) {   // draw outline?
				elem->addAttribute("stroke", "black");
				elem->addAttribute("stroke-width", XMLString(_penwidth));
			}
		}
		if (ddist > 0)
			elem->addAttribute("stroke-dasharray", XMLString(ddist));
		else if (ddist < 0)
			elem->addAttribute("stroke-dasharray", XMLString(_penwidth) + ' ' + XMLString(-ddist));
		actions->appendToPage(elem);
	}
	reset();
}


/** Stroke a quadratic spline through the midpoints of the lines defined by
 *  the previously recorded points. The spline starts	with a straight line
 *  from the first point to the mid-point of the first line.  The spline ends
 *  with a straight line from the mid-point of the last line to the last point.
 *  If ddist=0, the spline is stroked solid. Otherwise ddist denotes the length
 *  of the dashes and the gaps inbetween.
 *  @param[in] ddist length of dashes and gaps */
void TpicSpecialHandler::drawSplines (double ddist, SpecialActions *actions) {
	if (actions && !_points.empty()) {
		const size_t size = _points.size();
		if (size < 3)
			drawLines(true, false, ddist, actions);
		else {
			double x = actions->getX();
			double y = actions->getY();
			DPair p(x,y);
			ostringstream oss;
			oss << 'M' << XMLString(x+_points[0].x()) << ',' << XMLString(y+_points[0].y());
			DPair mid = p+_points[0]+(_points[1]-_points[0])/2.0;
			oss << 'L' << XMLString(mid.x()) << ',' << XMLString(mid.y());
			actions->embed(p+_points[0]);
			for (size_t i=1; i < size-1; i++) {
				const DPair p0 = p+_points[i-1];
				const DPair p1 = p+_points[i];
				const DPair p2 = p+_points[i+1];
				mid = p1+(p2-p1)/2.0;
				oss << 'Q' << XMLString(p1.x()) << ',' << XMLString(p1.y())
					 << ' ' << XMLString(mid.x()) << ',' << XMLString(mid.y());
				actions->embed(mid);
				actions->embed((p0+p1*6.0+p2)/8.0, _penwidth);
			}
			if (_points[0] == _points[size-1])  // closed path?
				oss << 'Z';
			else {
				oss << 'L' << XMLString(x+_points[size-1].x()) << ',' << XMLString(y+_points[size-1].y());
				actions->embed(p+_points[size-1]);
			}

			Color color = actions->getColor();
			color *= _fill;
			XMLElementNode *path = new XMLElementNode("path");
			if (_fill >= 0) {
				if (_points[0] != _points[size-1])
					oss << 'Z';
				path->addAttribute("fill", color.rgbString());
			}
			else
				path->addAttribute("fill", "none");

			path->addAttribute("d", oss.str());
			path->addAttribute("stroke", actions->getColor().rgbString());
			path->addAttribute("stroke-width", XMLString(_penwidth));
			if (ddist > 0)
				path->addAttribute("stroke-dasharray", XMLString(ddist));
			else if (ddist < 0)
				path->addAttribute("stroke-dasharray", XMLString(_penwidth) + ' ' + XMLString(-ddist));
			actions->appendToPage(path);
		}
	}
	reset();
}


/** Draws an elliptical arc.
 *  @param[in] cx x-coordinate of arc center
 *  @param[in] cy y-coordinate of arc center
 *  @param[in] rx length of horizonal semi-axis
 *  @param[in] ry length of vertical semi-axis
 *  @param[in] angle1 starting angle (clockwise) relative to x-axis
 *  @param[in] angle2 ending angle (clockwise) relative to x-axis */
void TpicSpecialHandler::drawArc (double cx, double cy, double rx, double ry, double angle1, double angle2, SpecialActions *actions) {
	if (actions) {
		const double PI2 = 4*asin(1.0);
		angle1 *= -1;
		angle2 *= -1;
		if (fabs(angle1) > PI2) {
			int n = (int)(angle1/PI2);
			angle1 = angle1 - n*PI2;
			angle2 = angle2 - n*PI2;
		}

		double x = cx + actions->getX();
		double y = cy + actions->getY();
		XMLElementNode *elem=0;
		if (fabs(angle1-angle2) >= PI2) {  // closed ellipse?
			elem = new XMLElementNode("ellipse");
			elem->addAttribute("cx", XMLString(x));
			elem->addAttribute("cy", XMLString(y));
			elem->addAttribute("rx", XMLString(rx));
			elem->addAttribute("ry", XMLString(ry));
		}
		else {
			if (angle1 < 0)
				angle1 = PI2+angle1;
			if (angle2 < 0)
				angle2 = PI2+angle2;
			elem = new XMLElementNode("path");
			int large_arg = fabs(angle1-angle2) > PI2/2 ? 0 : 1;
			int sweep_flag = angle1 > angle2 ? 0 : 1;
			if (angle1 > angle2) {
				large_arg = 1-large_arg;
				sweep_flag = 1-sweep_flag;
			}
			ostringstream oss;
			oss << 'M' << XMLString(x+rx*cos(angle1)) << ',' << XMLString(y+ry*sin(-angle1))
				 << 'A' << XMLString(rx) << ',' << XMLString(ry)
				 << " 0 "
				 << large_arg << ' ' << sweep_flag << ' '
				 << XMLString(x+rx*cos(angle2)) << ',' << XMLString(y-ry*sin(angle2));
			if (_fill >= 0)
				oss << 'Z';
			elem->addAttribute("d", oss.str());
		}
		elem->addAttribute("stroke-width", _penwidth);
		elem->addAttribute("stroke", actions->getColor().rgbString());
		elem->addAttribute("stroke-linecap", "round");
		elem->addAttribute("fill", "none");
		if (_fill >= 0) {
			Color color=actions->getColor();
			color *= _fill;
			elem->addAttribute("fill", color.rgbString());
		}
		else
			elem->addAttribute("fill", "none");
		actions->appendToPage(elem);
		actions->embed(BoundingBox(cx-rx, cy-ry, cx+rx, cy+ry));
	}
	reset();
}


#define cmd_id(c1,c2) ((c1 << 8) | c2)

bool TpicSpecialHandler::process (const char *prefix, istream &is, SpecialActions *actions) {
	if (!prefix || strlen(prefix) != 2)
		return false;

	const double PT=0.07227; // factor for milli-inch to TeX points
	StreamInputBuffer ib(is);
	BufferInputReader in(ib);
	switch (cmd_id(prefix[0], prefix[1])) {
		case cmd_id('p','n'): // set pen width in milli-inches
			_penwidth = in.getDouble()*PT;
			break;
		case cmd_id('b','k'): // set fill color to black
			_fill = 0;
			break;
		case cmd_id('w','h'): // set fill color to white
			_fill = 1;
			break;
		case cmd_id('s','h'): // set fill color to given gray level
			in.skipSpace();
			_fill = in.eof() ? 0.5 : max(0.0, min(1.0, in.getDouble()));
			break;
		case cmd_id('t','x'): // set fill pattern
			break;
		case cmd_id('p','a'): { // add point to path
			double x=in.getDouble()*PT;
			double y=in.getDouble()*PT;
			_points.push_back(DPair(x,y));
			break;
		}
		case cmd_id('f','p'): // draw solid lines through recorded points; close and fill path if fill color was defined
			drawLines(true, _fill >= 0, 0, actions);
			break;
		case cmd_id('i','p'): // don't draw outlines but close the recorded path and fill the resulting polygon
			drawLines(false, true, 0, actions);
			break;
		case cmd_id('d','a'): // as fp but draw dashed lines
			drawLines(true, _fill >= 0, in.getDouble()*72.27, actions);
			break;
		case cmd_id('d','t'): // as fp but draw dotted lines
			drawLines(true, _fill >= 0, -in.getDouble()*72.27, actions);
			break;
		case cmd_id('s','p'): { // draw quadratic splines through recorded points
			double ddist = in.getDouble();
			drawSplines(ddist, actions);
			break;
		}
		case cmd_id('a','r'): { // draw elliptical arc
			double cx = in.getDouble()*PT;
			double cy = in.getDouble()*PT;
			double rx = in.getDouble()*PT;
			double ry = in.getDouble()*PT;
			double a1 = in.getDouble();
			double a2 = in.getDouble();
			drawArc(cx, cy, rx, ry, a1, a2, actions);
			break;
		}
		case cmd_id('i','a'): { // fill elliptical arc
			double cx = in.getDouble()*PT;
			double cy = in.getDouble()*PT;
			double rx = in.getDouble()*PT;
			double ry = in.getDouble()*PT;
			double a1 = in.getDouble();
			double a2 = in.getDouble();
			if (_fill < 0)
				_fill = 1;
			drawArc(cx, cy, rx, ry, a1, a2, actions);
			if (_fill < 0)
				_fill = -1;
			break;
		}
		default:
			return false;
	}
	return true;
}


const char** TpicSpecialHandler::prefixes () const {
	static const char *pfx[] = {"ar", "bk", "da", "dt", "fp", "ia", "ip", "pa", "pn", "sh", "sp", "tx", "wh", 0};
	return pfx;
}