/*
 * kldp.org login test.
 *
 * gcc -o curltest2 curltest2.c -Wall `pkg-config --cflags --libs libcurl`
 *
 * ./curltest2 your_id your_passwd
 *
 * bushi at mizi dot com
 *
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

#include <curl/curl.h>

#define URL_DEFAULT    "http://kldp.org/front-1007"
#define COOKIE_DEFAULT "kldp_cookie_1"

#define URL_LOGIN    "http://kldp.org/front-1007?destination=front-1007"
#define COOKIE_LOGIN "kldp_cookie_2"

#define POST_LOGIN_FMT "name=%s&pass=%s&form_id=user_login_block"

typedef struct content_s {
	size_t len;
	char *buf;
} content_t;

static void dump_content(content_t *content)
{
	if (!content || !content->buf)
		return;

	content->buf[content->len] = 0;
	printf("%s\n", content->buf);
	return;
}


static void init_content(content_t *content)
{
	if (content)
		content->len = 0;
}

static void free_content(content_t *content)
{
	if (content->buf)
		free(content->buf);
	free(content);
}

static content_t *new_content(void)
{
	content_t *content;
	content = malloc(sizeof(content));
	if (!content) {
		perror("malloc()");
		return NULL;
	}
	content->buf = NULL;
	init_content(content);
	return content;
}

static int write_to_file(const char *name, content_t *content)
{
	int fd, ret;

	if (!content || !content->buf)
		return -1;

	fd = open(name, O_CREAT | O_WRONLY, 0600);
	if (fd < 0) {
		perror(name);
		return fd;
	}
	ret = write(fd, content->buf, content->len);
	close(fd);
	if (ret < 0) {
		perror(name);
	}
	return ret;
}

static size_t curl_write_cb(void *ptr, size_t size, size_t nmemb, void *stream)
{
	size_t addition = size * nmemb;
	char *new_buf;
	content_t *content = stream;

	if (!addition)
		return 0;
	if (!content)
		return addition;

	new_buf = realloc(content->buf, content->len + addition + 1);
	if (!new_buf) {
		perror("realloc()");
		return 0;
	}
	content->buf = new_buf;

	memcpy(content->buf + content->len, ptr, addition);
	content->len += addition;

	return addition;
}

static CURLcode request(const char *id, const char *url,
			content_t *body, content_t *header,
			const char *cookie, const char *postdata, int postlen)
{
	CURL *curl;
	CURLcode res;

	curl = curl_easy_init();
	if (!curl)
		return -1;

	init_content(body);
	init_content(header);

	/* verbosity */
	curl_easy_setopt(curl, CURLOPT_VERBOSE, 10);

	/* header, body */
	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, curl_write_cb);
	curl_easy_setopt(curl, CURLOPT_WRITEDATA, body);
	curl_easy_setopt(curl, CURLOPT_WRITEHEADER, header);

	/* POST */
	curl_easy_setopt(curl, CURLOPT_POSTFIELDS, postdata);
	curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, postlen);

	/* cookie */
	curl_easy_setopt(curl, CURLOPT_COOKIEFILE, cookie);

	/* url */
	curl_easy_setopt(curl, CURLOPT_URL, url);

	res = curl_easy_perform(curl);
	if (res)
		fprintf(stderr, "CURL: %s\n",  curl_easy_strerror(res));

	curl_easy_cleanup(curl);

	return res;
}

int main(int argc, char **argv)
{
	CURLcode res;
	content_t *body, *header;
	char poststr[128];
	int ret;

	if (argc < 3) {
		fprintf(stderr, "%s <id> <pass>\n", argv[0]);
		return 1;
	}
	snprintf(poststr, sizeof(poststr), POST_LOGIN_FMT, argv[1], argv[2]);

	unlink(COOKIE_DEFAULT);
	unlink(COOKIE_LOGIN);

	body = new_content();
	header = new_content();

	res = request("first", URL_DEFAULT, NULL, header, 
			NULL, NULL, 0);
	if (res)
		goto out;

	ret = write_to_file(COOKIE_DEFAULT, header);
	if (ret < 0)
		goto out;

	res = request("second", URL_LOGIN, NULL, header, 
			COOKIE_DEFAULT, poststr, strlen(poststr));
	if (res)
		goto out;

	ret = write_to_file(COOKIE_LOGIN, header);
	if (ret < 0)
		goto out;

	res = request("third", URL_DEFAULT, body, header, 
			COOKIE_LOGIN, NULL, 0);
	if (res)
		goto out;

//	dump_content(header);
	dump_content(body);
//	write_to_file("kldp.html", body);

 out:
	free_content(body);
	free_content(header);
	return 0;
}