#include "mupdf/fitz.h"
#include "svg-imp.h"

#include <string.h>
#include <math.h>

int svg_is_whitespace_or_comma(int c)
{
	 return (c == 0x20) || (c == 0x9) || (c == 0xD) || (c == 0xA) || (c == ',');
}

int svg_is_whitespace(int c)
{
	return (c == 0x20) || (c == 0x9) || (c == 0xD) || (c == 0xA);
}

int svg_is_alpha(int c)
{
	return (c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z');
}

int svg_is_digit(int c)
{
	return (c >= '0' && c <= '9') ||
		(c == 'e') || (c == 'E') ||
		(c == '+') || (c == '-') || (c == '.');
}

const char *
svg_lex_number(float *fp, const char *ss)
{
	const char *s = ss;
	if (*s == '-')
		++s;
	while (*s >= '0' && *s <= '9')
		++s;
	if (*s == '.') {
		++s;
		while (*s >= '0' && *s <= '9')
			++s;
	}
	if (*s == 'e' || *s == 'E') {
		++s;
		if (*s == '+' || *s == '-')
			++s;
		while (*s >= '0' && *s <= '9')
			++s;
	}
	*fp = fz_atof(ss);
	return s;
}

float
svg_parse_number(const char *str, float min, float max, float inherit)
{
	float x;
	if (!strcmp(str, "inherit"))
		return inherit;
	x = fz_atof(str);
	if (x < min) return min;
	if (x > max) return max;
	return x;
}

/* Return length/coordinate in points */
float
svg_parse_length(const char *str, float percent, float font_size)
{
	char *end;
	float val;

	val = fz_strtof(str, &end);
	if (end == str)
		return 0; /* failed */

	if (!strcmp(end, "px")) return val;

	if (!strcmp(end, "pt")) return val * 1.0f;
	if (!strcmp(end, "pc")) return val * 12.0f;
	if (!strcmp(end, "mm")) return val * 2.83464567f;
	if (!strcmp(end, "cm")) return val * 28.3464567f;
	if (!strcmp(end, "in")) return val * 72.0f;

	if (!strcmp(end, "em")) return val * font_size;
	if (!strcmp(end, "ex")) return val * font_size * 0.5f;

	if (!strcmp(end, "%"))
		return val * percent * 0.01f;

	if (end[0] == 0)
		return val;

	return 0;
}

/* Return angle in degrees */
float
svg_parse_angle(const char *str)
{
	char *end;
	float val;

	val = fz_strtof(str, &end);
	if (end == str)
		return 0; /* failed */

	if (!strcmp(end, "deg"))
		return val;

	if (!strcmp(end, "grad"))
		return val * 0.9f;

	if (!strcmp(end, "rad"))
		return val * FZ_RADIAN;

	return val;
}

/* Coordinate transformations */
fz_matrix
svg_parse_transform(fz_context *ctx, svg_document *doc, const char *str, fz_matrix transform)
{
	char keyword[20];
	int keywordlen;
	float args[6];
	int nargs;

	nargs = 0;
	keywordlen = 0;

	while (*str)
	{
		while (svg_is_whitespace_or_comma(*str))
			str ++;
		if (*str == 0)
			break;

		/*
		 * Parse keyword and opening parenthesis.
		 */

		keywordlen = 0;
		while (svg_is_alpha(*str) && keywordlen < sizeof(keyword) - 1)
			keyword[keywordlen++] = *str++;
		keyword[keywordlen] = 0;

		if (keywordlen == 0)
			fz_throw(ctx, FZ_ERROR_SYNTAX, "expected keyword in transform attribute");

		while (svg_is_whitespace(*str))
			str ++;

		if (*str != '(')
			fz_throw(ctx, FZ_ERROR_SYNTAX, "expected opening parenthesis in transform attribute");
		str ++;

		/*
		 * Parse list of numbers until closing parenthesis
		 */

		nargs = 0;
		while (*str && *str != ')' && nargs < 6)
		{
			while (svg_is_whitespace_or_comma(*str))
				str ++;
			if (svg_is_digit(*str))
				str = svg_lex_number(&args[nargs++], str);
		}

		if (*str != ')')
			fz_throw(ctx, FZ_ERROR_SYNTAX, "expected closing parenthesis in transform attribute");
		str ++;

		/*
		 * Execute the transform.
		 */

		if (!strcmp(keyword, "matrix"))
		{
			fz_matrix m;

			if (nargs != 6)
				fz_throw(ctx, FZ_ERROR_SYNTAX, "wrong number of arguments to matrix(): %d", nargs);

			m.a = args[0];
			m.b = args[1];
			m.c = args[2];
			m.d = args[3];
			m.e = args[4];
			m.f = args[5];

			transform = fz_concat(transform, m);
		}

		else if (!strcmp(keyword, "translate"))
		{
			if (nargs != 2)
				fz_throw(ctx, FZ_ERROR_SYNTAX, "wrong number of arguments to translate(): %d", nargs);

			transform = fz_pre_translate(transform, args[0], args[1]);
		}

		else if (!strcmp(keyword, "scale"))
		{
			if (nargs == 1)
				transform = fz_pre_scale(transform, args[0], args[0]);
			else if (nargs == 2)
				transform = fz_pre_scale(transform, args[0], args[1]);
			else
				fz_throw(ctx, FZ_ERROR_SYNTAX, "wrong number of arguments to scale(): %d", nargs);
		}

		else if (!strcmp(keyword, "rotate"))
		{
			if (nargs != 1)
				fz_throw(ctx, FZ_ERROR_SYNTAX, "wrong number of arguments to rotate(): %d", nargs);
			transform = fz_pre_rotate(transform, args[0]);
		}

		else if (!strcmp(keyword, "skewX"))
		{
			fz_matrix m;

			if (nargs != 1)
				fz_throw(ctx, FZ_ERROR_SYNTAX, "wrong number of arguments to skewX(): %d", nargs);

			m.a = 1;
			m.b = 0;
			m.c = tanf(args[0] * FZ_DEGREE);
			m.d = 1;
			m.e = 0;
			m.f = 0;

			transform = fz_concat(transform, m);
		}

		else if (!strcmp(keyword, "skewY"))
		{
			fz_matrix m;

			if (nargs != 1)
				fz_throw(ctx, FZ_ERROR_SYNTAX, "wrong number of arguments to skewY(): %d", nargs);

			m.a = 1;
			m.b = tanf(args[0] * FZ_DEGREE);
			m.c = 0;
			m.d = 1;
			m.e = 0;
			m.f = 0;

			transform = fz_concat(transform, m);
		}

		else
		{
			fz_throw(ctx, FZ_ERROR_SYNTAX, "unknown transform function: %s", keyword);
		}
	}

	return transform;
}