/* 
 * Simple config parser 
 * Teodor Sigaev <teodor@sigaev.ru>
 */
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "postgres.h"

#include "dict.h"
#include "common.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=palloc(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_cfgdict(text *in, Map **m) {
	Map *mptr;
	char *ptr=VARDATA(in), *begin=NULL;
	char num=0;
	int state=CS_WAITKEY;

	while( ptr-VARDATA(in) < VARSIZE(in) - VARHDRSZ ) {
		if ( *ptr==',' ) num++;
		ptr++;
	}

	*m=mptr=(Map*)palloc( sizeof(Map)*(num+2) );
	memset(mptr, 0, sizeof(Map)*(num+2) );
	ptr=VARDATA(in);
	while( ptr-VARDATA(in) < VARSIZE(in) - VARHDRSZ ) {
		if (state==CS_WAITKEY) {
			if (isalpha(*ptr)) {
				begin=ptr;
				state=CS_INKEY;
			} else if ( !isspace(*ptr) )
				ereport(ERROR,
						(errcode(ERRCODE_SYNTAX_ERROR),
						 errmsg("syntax error"),
						 errdetail("Syntax error in position %d near \"%c\"",
								   (int) (ptr-VARDATA(in)), *ptr)));
		} else if (state==CS_INKEY) {
			if ( isspace(*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(*ptr) ) 
				ereport(ERROR,
						(errcode(ERRCODE_SYNTAX_ERROR),
						 errmsg("syntax error"),
						 errdetail("Syntax error in position %d near \"%c\"",
								   (int) (ptr-VARDATA(in)), *ptr)));
		} else if ( state==CS_WAITEQ ) {
			if ( *ptr=='=' )
				state=CS_WAITVALUE;
			else if ( !isspace(*ptr) )
				ereport(ERROR,
						(errcode(ERRCODE_SYNTAX_ERROR),
						 errmsg("syntax error"),
						 errdetail("Syntax error in position %d near \"%c\"",
								   (int) (ptr-VARDATA(in)), *ptr)));
		} else if ( state==CS_WAITVALUE ) {
			if ( *ptr=='"' ) {
				begin=ptr+1;
				state=CS_INVALUE;
			} else if ( !isspace(*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(*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(*ptr) )
				ereport(ERROR,
						(errcode(ERRCODE_SYNTAX_ERROR),
						 errmsg("syntax error"),
						 errdetail("Syntax error in position %d near \"%c\"",
								   (int) (ptr-VARDATA(in)), *ptr)));
		} else if ( state == CS_INESC ) {
			state=CS_INVALUE;
		} else if ( state == CS_IN2ESC ) {
			state=CS_IN2VALUE;
		} else 
			ereport(ERROR,
					(errcode(ERRCODE_SYNTAX_ERROR),
					 errmsg("bad parser state"),
					 errdetail("%d at position %d near \"%c\"",
								state, (int) (ptr-VARDATA(in)), *ptr)));
		ptr++;
	}

	if (state==CS_IN2VALUE) {
		mptr->value = nstrdup(begin, ptr-begin);
		mptr++;
	} else if ( !(state==CS_WAITDELIM || state==CS_WAITKEY) ) 
		ereport(ERROR,
				(errcode(ERRCODE_SYNTAX_ERROR),
				 errmsg("unexpected end of line")));
}