/******************************************************************************
 *
 *                Copyright (c) 2017-2019 by Löwenware Ltd
 *             Please, refer LICENSE file for legal information
 *
 ******************************************************************************/

/**
 * @file query.c
 * @author Ilja Kartašov <ik@lowenware.com>
 * @brief HTTP POST/GET query stream parser source file
 *
 * @see https://lowenware.com/aisl/
 */

#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include "query.h"


aisl_status_t
aislx_query_init( aislx_query_t        query,
                  size_t               total,
                  aislx_query_on_var   on_var,
                  void               * p_ctx )
{
	query->on_var = on_var;
	query->p_ctx  = p_ctx;
	query->data   = NULL;
	query->size   = 0;
	query->total  = 0;
	query->separator = 0;

	return AISL_SUCCESS;
}


void
aislx_query_release(aislx_query_t query)
{
	if (query->data)
		free(query->data);
}


static void
aislx_query_notify(const char * key, uint32_t k_len,
                   const char * val, uint32_t v_len,
                   aislx_query_t query)
{
	if (query->on_var) {
		if (query->on_var(key, k_len, val, v_len, query->p_ctx) != 0)
			query->on_var = NULL;
	}
}


static int32_t
aislx_query_process(aislx_query_t query, const char * data, int32_t length)
{
	const char *i = data,
             *key = data,
             *val = NULL;
	uint32_t k_len = 0;
	size_t result;

	for (result=0; result < length; result++) {
		char c;

		switch( (c = *i) ) {
		case '=':
			if (val)
				return -1;

			k_len = i-key;
			val   = i+1;
			break;

		case '&':
		case ';':
			if (!val)
				return -1;

			if (!query->separator)
				query->separator = c;

			if (query->separator == c) {
				aislx_query_notify(key, k_len, val, i-val, query);
				/* reset parser */
				key = (c == ';') ? i+2 : i+1;
				k_len = 0;
				val = NULL;
				break;
			}
		}
		i++;
	}

	if (query->total == result) {
		aislx_query_notify(key, k_len, val, i-val, query);
	} else {
		result = (key > i) ? i - data : key - data;
	}

	query->total -= result;

	return result;
}


aisl_status_t
aislx_query_feed(aislx_query_t query, const char *data, int32_t length)
{
	size_t processed;
	const char *source;

	if (query->data) {
		if (!(source = realloc(query->data, length + query->size)))
			return AISL_MALLOC_ERROR;

		length += query->size;
		query->data = (char*)source;
		query->size = length;

		memcpy((char*)&source[query->size], data, length);
	} else {
		source = data;
	}

	processed = aislx_query_process(query, source, length);

	if (processed < 0)
		return AISL_INPUT_ERROR;

	if (processed < length) {
		char *buffer;

		length -= processed;
		if (!(buffer = malloc(length)))
			return AISL_MALLOC_ERROR;

		memcpy(buffer, &source[processed], length);

		if (query->data)
			free(query->data);

		query->data = buffer;
		query->size = length;
	}

	return AISL_SUCCESS;
}