#include "form.h"

#include <stdio.h>
#include <stdlib.h>

struct form_parser
{
	FILE* f;
	char* buffer;
	int size;
	int pos;
};

struct form_parser* form_pull_parser_new( FILE* f )
{
	struct form_parser* fp = (struct form_parser*)malloc(sizeof(struct form_parser));
	if( !fp ) { return NULL; }

	fp->f = f;
	fp->buffer = malloc(32);
	fp->buffer[0] = '\0';
	fp->size = 32;
	fp->pos = 0;

	return fp;
}

void form_pull_parser_release( struct form_parser* fp )
{
	fclose(fp->f);
	free(fp->buffer);
	free(fp);
}

static void append_char( struct form_parser* fp, char ch )
{
	if( fp->pos == fp->size - 1 ) {
		fp->size += 32;
		fp->buffer = realloc( fp->buffer, fp->size );
	}
	fp->buffer[ fp->pos ] = ch;
	fp->buffer[ fp->pos+1 ] = '\0';
	fp->pos += 1;
}

static char* read_item( struct form_parser* fp, char delim )
{
	char ch;
	char escape[3] = "00";
	int tmp;

	// Clear any existing data
	fp->pos = 0;
	fp->buffer[0] = '\0';

	while( (ch=fgetc(fp->f)) != EOF ) {
		if( ch == delim ) { break; }

		if( ch == '%' ) {
			escape[0] = fgetc(fp->f);
			escape[1] = fgetc(fp->f);
			sscanf(escape, "%02x",&tmp);
			append_char( fp, tmp );
		} else {
			append_char( fp, ch );
		}
	}

	if( fp->pos == 0 ) {
		return NULL;
	}

	return fp->buffer;
}

char* form_pull_parser_read_key( struct form_parser* fp )
{
	return read_item( fp, '=' );
}
char* form_pull_parser_read_value( struct form_parser* fp )
{
	return read_item( fp, '&' );
}