/*
 * Copyright (c) 2004 Teodor Sigaev <teodor@sigaev.ru>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *        notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *        notice, this list of conditions and the following disclaimer in the
 *        documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the author nor the names of any co-contributors
 *        may be used to endorse or promote products derived from this software
 *        without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY CONTRIBUTORS ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL CONTRIBUTORS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
 * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "tlog.h"
#include "tmalloc.h"
#include "prs_hmap.h"



#define CS_WAITKEY	0
#define CS_INKEY	1
#define CS_WAITEQ	2
#define CS_WAITVALUE	3
#define CS_INVALUE	4
#define CS_IN2VALUE 5
#define CS_WAITDELIM	6
#define CS_INESC	7
#define CS_IN2ESC	8

static char *
nstrdup(char *ptr, int len) {
	char	   *res = tmalloc(len + 1),
			   *cptr;

	memcpy(res, ptr, len);
	res[len] = '\0';
	cptr = ptr = res;
	while (*ptr) {
		if (*ptr == '\\')
			ptr++;
		*cptr = *ptr;
		ptr++;
		cptr++;
	}
	*cptr = '\0';

	return res;
}

void
parse_hmap(char *in, HMap ** m) {
	HMap		   *mptr;
	char	   *ptr = in,
			   *begin = NULL;
	char		num = 0;
	int			state = CS_WAITKEY;

	while (*ptr)
	{
		if (*ptr == ',')
			num++;
		ptr++;
	}

	*m = mptr = (HMap *) t0malloc(sizeof(HMap) * (num + 2));
	ptr = in;
	while (*ptr) {
		if (state == CS_WAITKEY) {
			if (isalpha((unsigned char) *ptr)) {
				begin = ptr;
				state = CS_INKEY;
			} else if (!isspace((unsigned char) *ptr))	
				tlog(TL_ALARM|TL_EXIT,"parse_hmap: Syntax error in position %d near \"%c\"\n", (int) (ptr - in), *ptr);
		} else if (state == CS_INKEY) {
			if (isspace((unsigned char) *ptr)) {
				mptr->key = nstrdup(begin, ptr - begin);
				state = CS_WAITEQ;
			} else if (*ptr == '=') {
				mptr->key = nstrdup(begin, ptr - begin);
				state = CS_WAITVALUE;
			} else if (!isalpha((unsigned char) *ptr))
				tlog(TL_ALARM|TL_EXIT,"parse_hmap: Syntax error in position %d near \"%c\"\n", (int) (ptr - in), *ptr);
		} else if (state == CS_WAITEQ) {
			if (*ptr == '=')
				state = CS_WAITVALUE;
			else if (!isspace((unsigned char) *ptr))
				tlog(TL_ALARM|TL_EXIT,"parse_hmap: Syntax error in position %d near \"%c\"\n", (int) (ptr - in), *ptr);
		} else if (state == CS_WAITVALUE) {
			if (*ptr == '"') {
				begin = ptr + 1;
				state = CS_INVALUE;
			} else if (!isspace((unsigned char) *ptr)) {
				begin = ptr;
				state = CS_IN2VALUE;
			}
		} else if (state == CS_INVALUE) {
			if (*ptr == '"') {
				mptr->value = nstrdup(begin, ptr - begin);
				mptr++;
				state = CS_WAITDELIM;
			} else if (*ptr == '\\')
				state = CS_INESC;
		} else if (state == CS_IN2VALUE) {
			if (isspace((unsigned char) *ptr) || *ptr == ',') {
				mptr->value = nstrdup(begin, ptr - begin);
				mptr++;
				state = (*ptr == ',') ? CS_WAITKEY : CS_WAITDELIM;
			} else if (*ptr == '\\')
				state = CS_INESC;
		} else if (state == CS_WAITDELIM) {
			if (*ptr == ',')
				state = CS_WAITKEY;
			else if (!isspace((unsigned char) *ptr))
				tlog(TL_ALARM|TL_EXIT,"parse_hmap: Syntax error in position %d near \"%c\"\n", (int) (ptr - in), *ptr);
		} else if (state == CS_INESC)
			state = CS_INVALUE;
		else if (state == CS_IN2ESC)
			state = CS_IN2VALUE;
		else
			tlog(TL_CRIT|TL_EXIT,"parse_hmap: Bad parser state %d at position %d near \"%c\"\n", state, (int) (ptr - in), *ptr);
		ptr++;
	}

	if (state == CS_IN2VALUE) {
		mptr->value = nstrdup(begin, ptr - begin);
		mptr++;
	}
	else if (!(state == CS_WAITDELIM || state == CS_WAITKEY))
		tlog(TL_ALARM|TL_EXIT,"parse_hmap: unexpected end of line\n");
}

static int 
getnumber(char c)  {
	if ( c == '\0' )
		return 0;
	else if ( c >= '0' && c <= '9' )
		return c - '0';
	else if ( c >= 'A' && c <= 'F' )
		return c - 'A' + 10;
	else if ( c >= 'a' && c <= 'f' )
		return c - 'a' + 10;

	return -1;
}

static char * 
unescape(char *str, int len) {
	char *in = str, *out = tmalloc(sizeof(char)*(len+1));
	char *res = out; 

	while(in - str < len )  {
		char c = *in;

		if ( c == '+' ) 
			c = ' ';
		else if ( c == '%' ) {
			char *ptr = in;
			int  i1, i2;

			ptr++;
			if ( ptr - str >= len || (i1=getnumber(*ptr)) < 0 ) 
				goto process;
			ptr++;
			if ( ptr - str >= len || (i2=getnumber(*ptr)) < 0 ) 
				goto process;

			c = (i1<<4) | i2;

			in+=2;
		}

process:
		*out = c;
		out++; in++;
	}

	*out = '\0';

	return res;
}

#define QS_WAITKEY	1
#define QS_INKEY	2
#define QS_WAITVAL	3
#define QS_INVAL	4

int   
parse_query_string(char *in, HMap ** m) {
	HMap		*mptr;
	char	   	*ptr = in,
			   	*begin = NULL;
	char		num = 0;
	int			state = QS_WAITKEY;

	while (*ptr)
	{
		if (*ptr == '&')
			num++;
		ptr++;
	}

	*m = mptr = (HMap *) t0malloc(sizeof(HMap) * (num + 2));
	ptr = in;
	while (*ptr) {
		if ( state == QS_WAITKEY ) {
			if ( !( *ptr == '&'  || *ptr == '=' ) ) {
				begin = ptr;
				state = QS_INKEY;
			}
		} else if ( state == QS_INKEY ) {
			if ( *ptr == '=' ) {
				mptr->key = unescape( begin , ptr-begin );
				state = QS_WAITVAL;
			} else if ( *ptr == '&' ) {
				mptr->key = unescape( begin , ptr-begin );
				mptr->value = t0malloc(sizeof(char));
				mptr++;
				state = QS_WAITKEY;
			}
		} else if ( state == QS_WAITVAL ) {
			if ( *ptr == '&' ) {
				mptr->value = t0malloc(sizeof(char));
				state = QS_WAITKEY;
				mptr++;
			} else {
				begin = ptr;
				state = QS_INVAL;
			}
		} else if ( state == QS_INVAL ) {
			if ( *ptr == '&' ) {
				mptr->value = unescape( begin , ptr-begin );
				mptr++;
				state = QS_WAITKEY;
			} 
		} else
			tlog( TL_CRIT|TL_EXIT,"Wrong state of QUERY_STRING parser");

		ptr++;
	}

	if ( state == QS_INVAL ) {
		mptr->value = unescape( begin , ptr-begin );
		mptr++;
	} if ( state == QS_INKEY ) {
		mptr->key = unescape( begin , ptr-begin );
		mptr->value = t0malloc(sizeof(char));
		mptr++;
	} else if ( state == QS_WAITVAL ) {
		mptr->value = t0malloc(sizeof(char));
	}

	return mptr - *m;
}