/*
 * Asterisk -- An open source telephony toolkit.
 *
 * Copyright (C)  2004 - 2006, Tilghman Lesher
 *
 * Tilghman Lesher <curl-20050919@the-tilghman.com>
 * and Brian Wilkins <bwilkins@cfl.rr.com> (Added POST option)
 *
 * app_curl.c is distributed with no restrictions on usage or
 * redistribution.
 *
 * See http://www.asterisk.org for more information about
 * the Asterisk project. Please do not directly contact
 * any of the maintainers of this project for assistance;
 * the project provides a web site, mailing lists and IRC
 * channels for your use.
 *
 */

/*! \file
 * 
 * \brief Curl - Load a URL
 *
 * \author Tilghman Lesher <curl-20050919@the-tilghman.com>
 *
 * \note Brian Wilkins <bwilkins@cfl.rr.com> (Added POST option) 
 * 
 * \ingroup functions
 */
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <curl/curl.h>

#include "asterisk.h"

ASTERISK_FILE_VERSION(__FILE__, "Revision: 10932 ")

#include "asterisk/lock.h"
#include "asterisk/file.h"
#include "asterisk/logger.h"
#include "asterisk/channel.h"
#include "asterisk/pbx.h"
#include "asterisk/cli.h"
#include "asterisk/options.h"
#include "asterisk/module.h"
#include "asterisk/app.h"
#include "asterisk/utils.h"

static char *tdesc = "Load external URL";

LOCAL_USER_DECL;

struct MemoryStruct {
	char *memory;
	size_t size;
};

static void *myrealloc(void *ptr, size_t size)
{
	/* There might be a realloc() out there that doesn't like reallocing
	   NULL pointers, so we take care of it here */
	if (ptr)
		return ast_realloc(ptr, size);
	else
		return ast_malloc(size);
}

static size_t WriteMemoryCallback(void *ptr, size_t size, size_t nmemb, void *data)
{
	register int realsize = size * nmemb;
	struct MemoryStruct *mem = (struct MemoryStruct *)data;

	mem->memory = (char *)myrealloc(mem->memory, mem->size + realsize + 1);
	if (mem->memory) {
		memcpy(&(mem->memory[mem->size]), ptr, realsize);
		mem->size += realsize;
		mem->memory[mem->size] = 0;
	}
	return realsize;
}

static int curl_internal(struct MemoryStruct *chunk, char *url, char *post)
{
	CURL *curl;

	curl_global_init(CURL_GLOBAL_ALL);
	curl = curl_easy_init();

	if (!curl) {
		return -1;
	}

	curl_easy_setopt(curl, CURLOPT_URL, url);
	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);
	curl_easy_setopt(curl, CURLOPT_WRITEDATA, (void *)chunk);
	curl_easy_setopt(curl, CURLOPT_USERAGENT, "asterisk-libcurl-agent/1.0");

	if (post) {
		curl_easy_setopt(curl, CURLOPT_POST, 1);
		curl_easy_setopt(curl, CURLOPT_POSTFIELDS, post);
	}

	curl_easy_perform(curl);
	curl_easy_cleanup(curl);
	return 0;
}

static int acf_curl_exec(struct ast_channel *chan, char *cmd, char *info, char *buf, size_t len)
{
	struct localuser *u;
	struct MemoryStruct chunk = { NULL, 0 };
	AST_DECLARE_APP_ARGS(args,
		AST_APP_ARG(url);
		AST_APP_ARG(postdata);
	);

	*buf = '\0';
	
	if (ast_strlen_zero(info)) {
		ast_log(LOG_WARNING, "CURL requires an argument (URL)\n");
		return -1;
	}

	LOCAL_USER_ADD(u);

	AST_STANDARD_APP_ARGS(args, info);	
	
	if (!curl_internal(&chunk, args.url, args.postdata)) {
		if (chunk.memory) {
			chunk.memory[chunk.size] = '\0';
			if (chunk.memory[chunk.size - 1] == 10)
				chunk.memory[chunk.size - 1] = '\0';

			ast_copy_string(buf, chunk.memory, len);
			free(chunk.memory);
		}
	} else {
		ast_log(LOG_ERROR, "Cannot allocate curl structure\n");
	}

	LOCAL_USER_REMOVE(u);

	return 0;
}

struct ast_custom_function acf_curl = {
	.name = "CURL",
	.synopsis = "Retrieves the contents of a URL",
	.syntax = "CURL(url[|post-data])",
	.desc =
	"  url       - URL to retrieve\n"
	"  post-data - Optional data to send as a POST (GET is default action)\n",
	.read = acf_curl_exec,
};

int unload_module(void)
{
	int res;

	res = ast_custom_function_unregister(&acf_curl);

	STANDARD_HANGUP_LOCALUSERS;
	
	return res;
}

int load_module(void)
{
	int res;

	res = ast_custom_function_register(&acf_curl);

	return res;
}

char *description(void)
{
	return tdesc;
}

int usecount(void)
{
	int res;
	STANDARD_USECOUNT(res);
	return res;
}

char *key()
{
	return ASTERISK_GPL_KEY;
}