/*
Minetest
Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "httpfetch.h"
#include "porting.h" // for sleep_ms(), get_sysinfo(), secure_rand_fill_buf()
#include <iostream>
#include <sstream>
#include <list>
#include <map>
#include <cerrno>
#include <mutex>
#include "network/socket.h" // for select()
#include "threading/event.h"
#include "config.h"
#include "exceptions.h"
#include "debug.h"
#include "log.h"
#include "util/container.h"
#include "util/thread.h"
#include "version.h"
#include "settings.h"
#include "noise.h"

std::mutex g_httpfetch_mutex;
std::map<unsigned long, std::queue<HTTPFetchResult> > g_httpfetch_results;
PcgRandom g_callerid_randomness;

HTTPFetchRequest::HTTPFetchRequest() :
	timeout(g_settings->getS32("curl_timeout")),
	connect_timeout(timeout),
	useragent(std::string(PROJECT_NAME_C "/") + g_version_hash + " (" + porting::get_sysinfo() + ")")
{
}


static void httpfetch_deliver_result(const HTTPFetchResult &fetch_result)
{
	unsigned long caller = fetch_result.caller;
	if (caller != HTTPFETCH_DISCARD) {
		MutexAutoLock lock(g_httpfetch_mutex);
		g_httpfetch_results[caller].push(fetch_result);
	}
}

static void httpfetch_request_clear(unsigned long caller);

unsigned long httpfetch_caller_alloc()
{
	MutexAutoLock lock(g_httpfetch_mutex);

	// Check each caller ID except HTTPFETCH_DISCARD
	const unsigned long discard = HTTPFETCH_DISCARD;
	for (unsigned long caller = discard + 1; caller != discard; ++caller) {
		std::map<unsigned long, std::queue<HTTPFetchResult> >::iterator
			it = g_httpfetch_results.find(caller);
		if (it == g_httpfetch_results.end()) {
			verbosestream << "httpfetch_caller_alloc: allocating "
					<< caller << std::endl;
			// Access element to create it
			g_httpfetch_results[caller];
			return caller;
		}
	}

	FATAL_ERROR("httpfetch_caller_alloc: ran out of caller IDs");
	return discard;
}

unsigned long httpfetch_caller_alloc_secure()
{
	MutexAutoLock lock(g_httpfetch_mutex);

	// Generate random caller IDs and make sure they're not
	// already used or equal to HTTPFETCH_DISCARD
	// Give up after 100 tries to prevent infinite loop
	u8 tries = 100;
	unsigned long caller;

	do {
		caller = (((u64) g_callerid_randomness.next()) << 32) |
				g_callerid_randomness.next();

		if (--tries < 1) {
			FATAL_ERROR("httpfetch_caller_alloc_secure: ran out of caller IDs");
			return HTTPFETCH_DISCARD;
		}
	} while (g_httpfetch_results.find(caller) != g_httpfetch_results.end());

	verbosestream << "httpfetch_caller_alloc_secure: allocating "
		<< caller << std::endl;

	// Access element to create it
	g_httpfetch_results[caller];
	return caller;
}

void httpfetch_caller_free(unsigned long caller)
{
	verbosestream<<"httpfetch_caller_free: freeing "
			<<caller<<std::endl;

	httpfetch_request_clear(caller);
	if (caller != HTTPFETCH_DISCARD) {
		MutexAutoLock lock(g_httpfetch_mutex);
		g_httpfetch_results.erase(caller);
	}
}

bool httpfetch_async_get(unsigned long caller, HTTPFetchResult &fetch_result)
{
	MutexAutoLock lock(g_httpfetch_mutex);

	// Check that caller exists
	std::map<unsigned long, std::queue<HTTPFetchResult> >::iterator
		it = g_httpfetch_results.find(caller);
	if (it == g_httpfetch_results.end())
		return false;

	// Check that result queue is nonempty
	std::queue<HTTPFetchResult> &caller_results = it->second;
	if (caller_results.empty())
		return false;

	// Pop first result
	fetch_result = caller_results.front();
	caller_results.pop();
	return true;
}

#if USE_CURL
#include <curl/curl.h>

/*
	USE_CURL is on: use cURL based httpfetch implementation
*/

static size_t httpfetch_writefunction(
		char *ptr, size_t size, size_t nmemb, void *userdata)
{
	std::ostringstream *stream = (std::ostringstream*)userdata;
	size_t count = size * nmemb;
	stream->write(ptr, count);
	return count;
}

static size_t httpfetch_discardfunction(
		char *ptr, size_t size, size_t nmemb, void *userdata)
{
	return size * nmemb;
}

class CurlHandlePool
{
	std::list<CURL*> handles;

public:
	CurlHandlePool() = default;

	~CurlHandlePool()
	{
		for (std::list<CURL*>::iterator it = handles.begin();
				it != handles.end(); ++it) {
			curl_easy_cleanup(*it);
		}
	}
	CURL * alloc()
	{
		CURL *curl;
		if (handles.empty()) {
			curl = curl_easy_init();
			if (curl == NULL) {
				errorstream<<"curl_easy_init returned NULL"<<std::endl;
			}
		}
		else {
			curl = handles.front();
			handles.pop_front();
		}
		return curl;
	}
	void free(CURL *handle)
	{
		if (handle)
			handles.push_back(handle);
	}
};

class HTTPFetchOngoing
{
public:
	HTTPFetchOngoing(const HTTPFetchRequest &request, CurlHandlePool *pool);
	~HTTPFetchOngoing();

	CURLcode start(CURLM *multi);
	const HTTPFetchResult * complete(CURLcode res);

	const HTTPFetchRequest &getRequest()    const { return request; };
	const CURL             *getEasyHandle() const { return curl; };

private:
	CurlHandlePool *pool;
	CURL *curl;
	CURLM *multi;
	HTTPFetchRequest request;
	HTTPFetchResult result;
	std::ostringstream oss;
	struct curl_slist *http_header;
	curl_httppost *post;
};


HTTPFetchOngoing::HTTPFetchOngoing(const HTTPFetchRequest &request_,
		CurlHandlePool *pool_):
	pool(pool_),
	curl(NULL),
	multi(NULL),
	request(request_),
	result(request_),
	oss(std::ios::binary),
	http_header(NULL),
	post(NULL)
{
	curl = pool->alloc();
	if (curl == NULL) {
		return;
	}

	// Set static cURL options
	curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);
	curl_easy_setopt(curl, CURLOPT_FAILONERROR, 1);
	curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
	curl_easy_setopt(curl, CURLOPT_MAXREDIRS, 1);
	curl_easy_setopt(curl, CURLOPT_ENCODING, "gzip");

	std::string bind_address = g_settings->get("bind_address");
	if (!bind_address.empty()) {
		curl_easy_setopt(curl, CURLOPT_INTERFACE, bind_address.c_str());
	}

#if LIBCURL_VERSION_NUM >= 0x071304
	// Restrict protocols so that curl vulnerabilities in
	// other protocols don't affect us.
	// These settings were introduced in curl 7.19.4.
	long protocols =
		CURLPROTO_HTTP |
		CURLPROTO_HTTPS |
		CURLPROTO_FTP |
		CURLPROTO_FTPS;
	curl_easy_setopt(curl, CURLOPT_PROTOCOLS, protocols);
	curl_easy_setopt(curl, CURLOPT_REDIR_PROTOCOLS, protocols);
#endif

	// Set cURL options based on HTTPFetchRequest
	curl_easy_setopt(curl, CURLOPT_URL,
			request.url.c_str());
	curl_easy_setopt(curl, CURLOPT_TIMEOUT_MS,
			request.timeout);
	curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT_MS,
			request.connect_timeout);

	if (!request.useragent.empty())
		curl_easy_setopt(curl, CURLOPT_USERAGENT, request.useragent.c_str());

	// Set up a write callback that writes to the
	// ostringstream ongoing->oss, unless the data
	// is to be discarded
	if (request.caller == HTTPFETCH_DISCARD) {
		curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION,
				httpfetch_discardfunction);
		curl_easy_setopt(curl, CURLOPT_WRITEDATA, NULL);
	} else {
		curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION,
				httpfetch_writefunction);
		curl_easy_setopt(curl, CURLOPT_WRITEDATA, &oss);
	}

	// Set POST (or GET) data
	if (request.post_fields.empty() && request.post_data.empty()) {
		curl_easy_setopt(curl, CURLOPT_HTTPGET, 1);
	} else if (request.multipart) {
		curl_httppost *last = NULL;
		for (StringMap::iterator it = request.post_fields.begin();
				it != request.post_fields.end(); ++it) {
			curl_formadd(&post, &last,
					CURLFORM_NAMELENGTH, it->first.size(),
					CURLFORM_PTRNAME, it->first.c_str(),
					CURLFORM_CONTENTSLENGTH, it->second.size(),
					CURLFORM_PTRCONTENTS, it->second.c_str(),
					CURLFORM_END);
		}
		curl_easy_setopt(curl, CURLOPT_HTTPPOST, post);
		// request.post_fields must now *never* be
		// modified until CURLOPT_HTTPPOST is cleared
	} else if (request.post_data.empty()) {
		curl_easy_setopt(curl, CURLOPT_POST, 1);
		std::string str;
		for (auto &post_field : request.post_fields) {
			if (!str.empty())
				str += "&";
			str += urlencode(post_field.first);
			str += "=";
			str += urlencode(post_field.second);
		}
		curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE,
				str.size());
		curl_easy_setopt(curl, CURLOPT_COPYPOSTFIELDS,
				str.c_str());
	} else {
		curl_easy_setopt(curl, CURLOPT_POST, 1);
		curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE,
				request.post_data.size());
		curl_easy_setopt(curl, CURLOPT_POS<span class="hl kwa">local</span> S
<span class="hl kwa">if</span> minetest<span class="hl opt">.</span><span class="hl kwd">get_modpath</span><span class="hl opt">(</span><span class="hl str">&quot;intllib&quot;</span><span class="hl opt">)</span> <span class="hl kwa">then</span>
    S <span class="hl opt">=</span> intllib<span class="hl opt">.</span><span class="hl kwd">Getter</span><span class="hl opt">()</span>
<span class="hl kwa">else</span>
    S <span class="hl opt">=</span> <span class="hl kwa">function</span><span class="hl opt">(</span>s<span class="hl opt">,</span>a<span class="hl opt">,...)</span>a<span class="hl opt">={</span>a<span class="hl opt">,...}</span><span class="hl kwa">return</span> s<span class="hl opt">:</span><span class="hl kwb">gsub</span><span class="hl opt">(</span><span class="hl str">&quot;&#64;(%d+)&quot;</span><span class="hl opt">,</span><span class="hl kwa">function</span><span class="hl opt">(</span>n<span class="hl opt">)</span><span class="hl kwa">return</span> a<span class="hl opt">[</span><span class="hl kwb">tonumber</span><span class="hl opt">(</span>n<span class="hl opt">)]</span><span class="hl kwa">end</span><span class="hl opt">)</span><span class="hl kwa">end</span>
<span class="hl kwa">end</span>

advtrains<span class="hl opt">.</span><span class="hl kwd">register_wagon</span><span class="hl opt">(</span><span class="hl str">&quot;subway_wagon&quot;</span><span class="hl opt">, {</span>
	mesh<span class="hl opt">=</span><span class="hl str">&quot;advtrains_subway_wagon.b3d&quot;</span><span class="hl opt">,</span>
	textures <span class="hl opt">= {</span><span class="hl str">&quot;advtrains_subway_wagon.png&quot;</span><span class="hl opt">},</span>
	drives_on<span class="hl opt">={</span>default<span class="hl opt">=</span><span class="hl kwa">true</span><span class="hl opt">},</span>
	max_speed<span class="hl opt">=</span><span class="hl num">15</span><span class="hl opt">,</span>
	seats <span class="hl opt">= {</span>
		<span class="hl opt">{</span>
			name<span class="hl opt">=</span><span class="hl str">&quot;Driver stand&quot;</span><span class="hl opt">,</span>
			attach_offset<span class="hl opt">={</span>x<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">,</span> y<span class="hl opt">=</span><span class="hl num">10</span><span class="hl opt">,</span> z<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">},</span>
			view_offset<span class="hl opt">={</span>x<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">,</span> y<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">,</span> z<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">},</span>
			group<span class="hl opt">=</span><span class="hl str">&quot;dstand&quot;</span><span class="hl opt">,</span>
		<span class="hl opt">},</span>
		<span class="hl opt">{</span>
			name<span class="hl opt">=</span><span class="hl str">&quot;1&quot;</span><span class="hl opt">,</span>
			attach_offset<span class="hl opt">={</span>x<span class="hl opt">=-</span><span class="hl num">4</span><span class="hl opt">,</span> y<span class="hl opt">=</span><span class="hl num">8</span><span class="hl opt">,</span> z<span class="hl opt">=</span><span class="hl num">8</span><span class="hl opt">},</span>
			view_offset<span class="hl opt">={</span>x<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">,</span> y<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">,</span> z<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">},</span>
			group<span class="hl opt">=</span><span class="hl str">&quot;pass&quot;</span><span class="hl opt">,</span>
		<span class="hl opt">},</span>
		<span class="hl opt">{</span>
			name<span class="hl opt">=</span><span class="hl str">&quot;2&quot;</span><span class="hl opt">,</span>
			attach_offset<span class="hl opt">={</span>x<span class="hl opt">=</span><span class="hl num">4</span><span class="hl opt">,</span> y<span class="hl opt">=</span><span class="hl num">8</span><span class="hl opt">,</span> z<span class="hl opt">=</span><span class="hl num">8</span><span class="hl opt">},</span>
			view_offset<span class="hl opt">={</span>x<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">,</span> y<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">,</span> z<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">},</span>
			group<span class="hl opt">=</span><span class="hl str">&quot;pass&quot;</span><span class="hl opt">,</span>
		<span class="hl opt">},</span>
		<span class="hl opt">{</span>
			name<span class="hl opt">=</span><span class="hl str">&quot;3&quot;</span><span class="hl opt">,</span>
			attach_offset<span class="hl opt">={</span>x<span class="hl opt">=-</span><span class="hl num">4</span><span class="hl opt">,</span> y<span class="hl opt">=</span><span class="hl num">8</span><span class="hl opt">,</span> z<span class="hl opt">=-</span><span class="hl num">8</span><span class="hl opt">},</span>
			view_offset<span class="hl opt">={</span>x<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">,</span> y<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">,</span> z<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">},</span>
			group<span class="hl opt">=</span><span class="hl str">&quot;pass&quot;</span><span class="hl opt">,</span>
		<span class="hl opt">},</span>
		<span class="hl opt">{</span>
			name<span class="hl opt">=</span><span class="hl str">&quot;4&quot;</span><span class="hl opt">,</span>
			attach_offset<span class="hl opt">={</span>x<span class="hl opt">=</span><span class="hl num">4</span><span class="hl opt">,</span> y<span class="hl opt">=</span><span class="hl num">8</span><span class="hl opt">,</span> z<span class="hl opt">=-</span><span class="hl num">8</span><span class="hl opt">},</span>
			view_offset<span class="hl opt">={</span>x<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">,</span> y<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">,</span> z<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">},</span>
			group<span class="hl opt">=</span><span class="hl str">&quot;pass&quot;</span><span class="hl opt">,</span>
		<span class="hl opt">},</span>
	<span class="hl opt">},</span>
	seat_groups <span class="hl opt">= {</span>
		dstand<span class="hl opt">={</span>
			name <span class="hl opt">=</span> <span class="hl str">&quot;Driver Stand&quot;</span><span class="hl opt">,</span>
			access_to <span class="hl opt">= {</span><span class="hl str">&quot;pass&quot;</span><span class="hl opt">},</span>
			require_doors_open<span class="hl opt">=</span><span class="hl kwa">true</span><span class="hl opt">,</span>
			driving_ctrl_access<span class="hl opt">=</span><span class="hl kwa">true</span><span class="hl opt">,</span>
		<span class="hl opt">},</span>
		pass<span class="hl opt">={</span>
			name <span class="hl opt">=</span> <span class="hl str">&quot;Passenger area&quot;</span><span class="hl opt">,</span>
			access_to <span class="hl opt">= {</span><span class="hl str">&quot;dstand&quot;</span><span class="hl opt">},</span>
			require_doors_open<span class="hl opt">=</span><span class="hl kwa">true</span><span class="hl opt">,</span>
		<span class="hl opt">},</span>
	<span class="hl opt">},</span>
	assign_to_seat_group <span class="hl opt">= {</span><span class="hl str">&quot;pass&quot;</span><span class="hl opt">,</span> <span class="hl str">&quot;dstand&quot;</span><span class="hl opt">},</span>
	doors<span class="hl opt">={</span>
		open<span class="hl opt">={</span>
			<span class="hl opt">[-</span><span class="hl num">1</span><span class="hl opt">]={</span>frames<span class="hl opt">={</span>x<span class="hl opt">=</span><span class="hl num">0</span><span class="hl opt">,</span> y<span class="hl opt">=</span><span class="hl num">20</span><span class="hl opt">},</span> time<span class="hl opt">=</span><span class="hl num">1</span><span class="hl opt">},</span>
			<span class="hl opt">[</span><span class="hl num">1</span><span class="hl opt">]={</span>frames<span class="hl opt">={</span>x<span class="hl opt">=</span><span class="hl num">40</span><span class="hl opt">,</span> y<span class="hl opt">=</span><span class="hl num">60</span><span class="hl opt">},</span> time<span class="hl opt">=</span><span class="hl num">1</span><span class="hl opt">},</span>
			sound <span class="hl opt">=</span> <span class="hl str">&quot;advtrains_subway_dopen&quot;</span><span class="hl opt">,</span>
		<span class="hl opt">},</span>
		close<span class="hl opt">={</span>
			<span class="hl opt">[-</span><span class="hl num">1</span><span class="hl opt">]={</span>frames<span class="hl opt">={</span>x<span class="hl opt">=</span><span class="hl num">20</span><span class="hl opt">,</span> y<span class="hl opt">=</span><span class="hl num">40</span><span class="hl opt">},</span> time<span class="hl opt">=</span><span class="hl num">1</span><span class="hl opt">},</span>
			<span class="hl opt">[</span><span class="hl num">1</span><span class="hl opt">]={</span>frames<span class="hl opt">={</span>x<span class="hl opt">=</span><span class="hl num">60</span><span class="hl opt">,</span> y<span class="hl opt">=</span><span class="hl num">80</span><span class="hl opt">},</span> time<span class="hl opt">=</span><span class="hl num">1</span><span class="hl opt">},</span>
			sound <span class="hl opt">=</span> <span class="hl str">&quot;advtrains_subway_dclose&quot;</span><span class="hl opt">,</span>
		<span class="hl opt">}</span>
	<span class="hl opt">},</span>
	door_entry<span class="hl opt">={-</span><span class="hl num">1</span><span class="hl opt">,</span> <span class="hl num">1</span><span class="hl opt">},</span>
	visual_size <span class="hl opt">= {</span>x<span class="hl opt">=</span><span class="hl num">1</span><span class="hl opt">,</span> y<span class="hl opt">=</span><span class="hl num">1</span><span class="hl opt">},</span>
	wagon_span<span class="hl opt">=</span><span class="hl num">2</span><span class="hl opt">,</span>
	<span class="hl slc">--collisionbox = {-1.0,-0.5,-1.8, 1.0,2.5,1.8},</span>
	collisionbox <span class="hl opt">= {-</span><span class="hl num">1.0</span><span class="hl opt">,-</span><span class="hl num">0.5</span><span class="hl opt">,-</span><span class="hl num">1.0</span><span class="hl opt">,</span> <span class="hl num">1.0</span><span class="hl opt">,</span><span class="hl num">2.5</span><span class="hl opt">,</span><span class="hl num">1.0</span><span class="hl opt">},</span>
	is_locomotive<span class="hl opt">=</span><span class="hl kwa">true</span><span class="hl opt">,</span>
	drops<span class="hl opt">={</span><span class="hl str">&quot;default:steelblock 4&quot;</span><span class="hl opt">},</span>
	horn_sound <span class="hl opt">=</span> <span class="hl str">&quot;advtrains_subway_horn&quot;</span><span class="hl opt">,</span>
	custom_on_velocity_change <span class="hl opt">=</span> <span class="hl kwa">function</span><span class="hl opt">(</span>self<span class="hl opt">,</span> velocity<span class="hl opt">,</span> old_velocity<span class="hl opt">,</span> dtime<span class="hl opt">)</span>
		<span class="hl kwa">if not</span> velocity <span class="hl kwa">or not</span> old_velocity <span class="hl kwa">then return end</span>
		<span class="hl kwa">if</span> old_velocity <span class="hl opt">==</span> <span class="hl num">0</span> <span class="hl kwa">and</span> velocity <span class="hl opt">&gt;</span> <span class="hl num">0</span> <span class="hl kwa">then</span>
			minetest<span class="hl opt">.</span><span class="hl kwd">sound_play</span><span