/*      
	This software is licensed under GPL-3, as shown in the file LICENSE
	Author: Linux Gruppe IRB
	Copyright: Linux Gruppe IRB, 2024
*/

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

#include "client.h"

static const char action_eid[] = "tcTokenURL=https://www.autentapp.de/AusweisAuskunft/WebServiceRequesterServlet?mode=xml";
static const char action_eid_ok[] = "<ns2:ResultMajor>http://www.bsi.bund.de/ecard/api/1.1/resultmajor#ok</ns2:ResultMajor>";
char errbuf[CURL_ERROR_SIZE];
int port;

static CURLcode client_action(CURL *curl, const char *action)
{
	char url[1024];

	snprintf(url, (sizeof url) - 1,
		 "http://127.0.0.1:%d/eID-Client?%s",
		 port, action);
	curl_easy_setopt(curl, CURLOPT_URL, url);
	return curl_easy_perform(curl);
}

static size_t read_eidData(char *data, size_t size, size_t nmemb, void *clientp)
{
	struct memory *mem = (struct memory *) clientp;
	size_t realsize = size * nmemb;

	char *ptr = realloc(mem->response, mem->size + realsize + 1);
	if (!ptr)
		return 0;	/* out of memory! */
 
	mem->response = ptr;
	memcpy(&(mem->response[mem->size]), data, realsize);
	mem->size += realsize;
	mem->response[mem->size] = 0;
	return realsize;
}

char *eidResponse(CURL *curl)
{
	struct memory eidData = {0};
	char *url = NULL;
	long code;
	int r;

	curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, &errbuf);
	curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 0);

#define MAX_TRIES 10

	if (port == 41325)
	{
		for (int tries = 1; tries <= MAX_TRIES; tries++)
		{
			if ((r = client_action(curl, action_eid)) == CURLE_OK)
				break;

			sleep(1);
		}
	}
	else
		r = client_action(curl, action_eid);

	if (r != CURLE_OK)
		return NULL;
	
	while ((curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &code) == CURLE_OK) && (code >= 300) &&
	       (code < 400) && (curl_easy_getinfo(curl, CURLINFO_REDIRECT_URL, &url) == CURLE_OK) && url)
	{
		/* follow redirects manually to make sure that we get authenticated
	 	* data exclusively from https://www.autentapp.de, which we use as
	 	* trusted source for comparison against the reference data */
		if (strstr(url, "https://www.autentapp.de"))
		{
			curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, read_eidData);
			curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *) &eidData);
		}

		curl_easy_setopt(curl, CURLOPT_URL, url);

		if ((r = curl_easy_perform(curl) != CURLE_OK))
			break;

		curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, NULL);
		curl_easy_setopt(curl, CURLOPT_WRITEDATA, NULL);
	}

	if ((r == CURLE_OK) && (strstr(eidData.response, action_eid_ok) != NULL))
		return eidData.response;
	else
		return NULL;
}