/*
 *  Phusion Passenger - https://www.phusionpassenger.com/
 *  Copyright (c) 2011-2018 Phusion Holding B.V.
 *
 *  "Passenger", "Phusion Passenger" and "Union Station" are registered
 *  trademarks of Phusion Holding B.V.
 *
 *  Permission is hereby granted, free of charge, to any person obtaining a copy
 *  of this software and associated documentation files (the "Software"), to deal
 *  in the Software without restriction, including without limitation the rights
 *  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 *  copies of the Software, and to permit persons to whom the Software is
 *  furnished to do so, subject to the following conditions:
 *
 *  The above copyright notice and this permission notice shall be included in
 *  all copies or substantial portions of the Software.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 *  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 *  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 *  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 *  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 *  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 *  THE SOFTWARE.
 */
#include <Core/Controller.h>
#include <AppTypeDetector/Detector.h>

/*************************************************************************
 *
 * Implements Core::Controller methods pertaining the initialization
 * of a request.
 *
 *************************************************************************/

namespace Passenger {
namespace Core {

using namespace std;
using namespace boost;


/****************************
 *
 * Private methods
 *
 ****************************/


struct Controller::RequestAnalysis {
	const LString *flags;
	ServerKit::HeaderTable::Cell *appGroupNameCell;
};


void
Controller::initializeFlags(Client *client, Request *req, RequestAnalysis &analysis) {
	if (analysis.flags != NULL) {
		const LString::Part *part = analysis.flags->start;
		while (part != NULL) {
			const char *data = part->data;
			const char *end  = part->data + part->size;
			while (data < end) {
				switch (*data) {
				case 'D':
					req->dechunkResponse = true;
					break;
				case 'B':
					req->requestBodyBuffering = true;
					break;
				case 'S':
					req->https = true;
					break;
				case 'C':
					req->strip100ContinueHeader = true;
					break;
				default:
					break;
				}
				data++;
			}
			part = part->next;
		}

		if (OXT_UNLIKELY(LoggingKit::getLevel() >= LoggingKit::DEBUG2)) {
			if (req->dechunkResponse) {
				SKC_TRACE(client, 2, "Dechunk flag detected");
			}
			if (req->requestBodyBuffering) {
				SKC_TRACE(client, 2, "Request body buffering enabled");
			}
			if (req->https) {
				SKC_TRACE(client, 2, "HTTPS flag detected");
			}
			if (req->strip100ContinueHeader) {
				SKC_TRACE(client, 2, "Stripping 100 Continue header");
			}
		}
	}
}

bool
Controller::respondFromTurboCache(Client *client, Request *req) {
	if (!turboCaching.isEnabled() || !turboCaching.responseCache.prepareRequest(this, req)) {
		return false;
	}

	SKC_TRACE(client, 2, "Turbocaching: trying to reply from cache (key \"" <<
		cEscapeString(req->cacheKey) << "\")");
	SKC_TRACE(client, 2, "Turbocache entries:\n" << turboCaching.responseCache.inspect());

	if (turboCaching.responseCache.requestAllowsFetching(req)) {
		ResponseCache<Request>::Entry entry(turboCaching.responseCache.fetch(req,
			ev_now(getLoop())));
		if (entry.valid()) {
			SKC_TRACE(client, 2, "Turbocaching: cache hit (key \"" <<
				cEscapeString(req->cacheKey) << "\")");
			turboCaching.writeResponse(this, client, req, entry);
			if (!req->ended()) {
				endRequest(&client, &req);
			}
			return true;
		} else {
			SKC_TRACE(client, 2, "Turbocaching: cache miss: " <<
				entry.getCacheMissReasonString() <<
				" (key \"" << cEscapeString(req->cacheKey) << "\")");
			return false;
		}
	} else {
		SKC_TRACE(client, 2, "Turbocaching: request not eligible for caching");
		return false;
	}
}

void
Controller::initializePoolOptions(Client *client, Request *req, RequestAnalysis &analysis) {
	boost::shared_ptr<Options> *options;

	if (mainConfig.singleAppMode) {
		P_ASSERT_EQ(poolOptionsCache.size(), 1);
		poolOptionsCache.lookupRandom(NULL, &options);
		req->options = **options;
	} else {
		ServerKit::HeaderTable::Cell *appGroupNameCell = analysis.appGroupNameCell;
		if (appGroupNameCell != NULL && appGroupNameCell->header->val.size > 0) {
			const LString *appGroupName = psg_lstr_make_contiguous(
				&appGroupNameCell->header->val,
				req->pool);
			HashedStaticString hAppGroupName(appGroupName->start->data,
				appGroupName->size);

			poolOptionsCache.lookup(hAppGroupName, &options);

			if (options != NULL) {
				req->options = **options;
			} else {
				createNewPoolOptions(client, req, hAppGroupName);
			}
		} else {
			disconnectWithError(&client, "the !~PASSENGER_APP_GROUP_NAME header must be set");
		}
	}

	if (!req->ended()) {
		// See comment for req->envvars to learn how it is different
		// from req->options.environmentVariables.
		req->envvars = req->secureHeaders.lookup(PASSENGER_ENV_VARS);
		if (req->envvars != NULL && req->envvars->size > 0) {
			req->envvars = psg_lstr_make_contiguous(req->envvars, req->pool);
			req->options.environmentVariables = StaticString(
				req->envvars->start->data,
				req->envvars->size);
		}

		// Allow certain options to be overridden on a per-request basis
		fillPoolOption(req, req->options.maxRequests, PASSENGER_MAX_REQUESTS);
	}
}

void
Controller::fillPoolOptionsFromConfigCaches(Options &options,
	psg_pool_t *pool, const ControllerRequestConfigPtr &requestConfig)
{
	options.ruby = requestConfig->defaultRuby;
	options.nodejs = requestConfig->defaultNodejs;
	options.python = requestConfig->defaultPython;
	options.meteorAppSettings = requestConfig->defaultMeteorAppSettings;
	options.fileDescriptorUlimit = requestConfig->defaultAppFileDescriptorUlimit;

	options.logLevel = int(LoggingKit::getLevel());
	options.integrationMode = psg_pstrdup(pool, mainConfig.integrationMode);
	options.userSwitching = mainConfig.userSwitching;
	options.defaultUser = requestConfig->defaultUser;
	options.defaultGroup = requestConfig->defaultGroup;
	options.minProcesses = requestConfig->defaultMinInstances;
	options.maxPreloaderIdleTime = requestConfig->defaultMaxPreloaderIdleTime;
	options.maxRequestQueueSize = requestConfig->defaultMaxRequestQueueSize;
	options.abortWebsocketsOnProcessShutdown = requestConfig->defaultAbortWebsocketsOnProcessShutdown;
	options.forceMaxConcurrentRequestsPerProcess = requestConfig->defaultForceMaxConcurrentRequestsPerProcess;
	options.environment = requestConfig->defaultEnvironment;
	options.spawnMethod = requestConfig->defaultSpawnMethod;
	options.loadShellEnvvars = requestConfig->defaultLoadShellEnvvars;
	options.statThrottleRate = mainConfig.statThrottleRate;
	options.maxRequests = requestConfig->defaultMaxRequests;

	/******************************/
}

void
Controller::fillPoolOption(Request *req, StaticString &field,
	const HashedStaticString &name)
{
	const LString *value = req->secureHeaders.lookup(name);
	if (value != NULL && value->size > 0) {
		value = psg_lstr_make_contiguous(value, req->pool);
		field = StaticString(value->start->data, value->size);
	}
}

void
Controller::fillPoolOption(Request *req, bool &field,
	const HashedStaticString &name)
{
	const LString *value = req->secureHeaders.lookup(name);
	if (value != NULL && value->size > 0) {
		field = psg_lstr_first_byte(value) == 't';
	}
}

void
Controller::fillPoolOption(Request *req, int &field,
	const HashedStaticString &name)
{
	const LString *value = req->secureHeaders.lookup(name);
	if (value != NULL && value->size > 0) {
		value = psg_lstr_make_contiguous(value, req->pool);
		field = stringToInt(StaticString(value->start->data, value->size));
	}
}

void
Controller::fillPoolOption(Request *req, unsigned int &field,
	const HashedStaticString &name)
{
	const LString *value = req->secureHeaders.lookup(name);
	if (value != NULL && value->size > 0) {
		value = psg_lstr_make_contiguous(value, req->pool);
		field = stringToUint(StaticString(value->start->data, value->size));
	}
}

void
Controller::fillPoolOption(Request *req, unsigned long &field,
	const HashedStaticString &name)
{
	const LString *value = req->secureHeaders.lookup(name);
	if (value != NULL && value->size > 0) {
		value = psg_lstr_make_contiguous(value, req->pool);
		field = stringToUint(StaticString(value->start->data, value->size));
	}
}

void
Controller::fillPoolOption(Request *req, long &field,
	const HashedStaticString &name)
{
	const LString *value = req->secureHeaders.lookup(name);
	if (value != NULL && value->size > 0) {
		value = psg_lstr_make_contiguous(value, req->pool);
		field = stringToInt(StaticString(value->start->data, value->size));
	}
}

void
Controller::fillPoolOptionSecToMsec(Request *req, unsigned int &field,
	const HashedStaticString &name)
{
	const LString *value = req->secureHeaders.lookup(name);
	if (value != NULL && value->size > 0) {
		value = psg_lstr_make_contiguous(value, req->pool);
		field = stringToInt(StaticString(value->start->data, value->size)) * 1000;
	}
}

void
Controller::createNewPoolOptions(Client *client, Request *req,
	const HashedStaticString &appGroupName)
{
	ServerKit::HeaderTable &secureHeaders = req->secureHeaders;
	Options &options = req->options;

	SKC_TRACE(client, 2, "Creating new pool options: app group name=" << appGroupName);

	options = Options();

	const LString *scriptName = secureHeaders.lookup("!~SCRIPT_NAME");
	const LString *appRoot = secureHeaders.lookup("!~PASSENGER_APP_ROOT");
	if (scriptName == NULL || scriptName->size == 0) {
		if (appRoot == NULL || appRoot->size == 0) {
			const LString *documentRoot = secureHeaders.lookup("!~DOCUMENT_ROOT");
			if (OXT_UNLIKELY(documentRoot == NULL || documentRoot->size == 0)) {
				disconnectWithError(&client, "client did not send a !~PASSENGER_APP_ROOT or a !~DOCUMENT_ROOT header");
				return;
			}

			documentRoot = psg_lstr_make_contiguous(documentRoot, req->pool);
			appRoot = psg_lstr_create(req->pool,
				extractDirNameStatic(StaticString(documentRoot->start->data,
					documentRoot->size)));
		} else {
			appRoot = psg_lstr_make_contiguous(appRoot, req->pool);
		}
		options.appRoot = HashedStaticString(appRoot->start->data, appRoot->size);
	} else {
		if (appRoot == NULL || appRoot->size == 0) {
			const LString *documentRoot = secureHeaders.lookup("!~DOCUMENT_ROOT");
			if (OXT_UNLIKELY(documentRoot == NULL || documentRoot->size == 0)) {
				disconnectWithError(&client, "client did not send a !~DOCUMENT_ROOT header");
				return;
			}

			documentRoot = psg_lstr_null_terminate(documentRoot, req->pool);
			documentRoot = resolveSymlink(StaticString(documentRoot->start->data,
				documentRoot->size), req->pool);
			appRoot = psg_lstr_create(req->pool,
				extractDirNameStatic(StaticString(documentRoot->start->data,
					documentRoot->size)));
		} else {
			appRoot = psg_lstr_make_contiguous(appRoot, req->pool);
		}
		options.appRoot = HashedStaticString(appRoot->start->data, appRoot->size);
		scriptName = psg_lstr_make_contiguous(scriptName, req->pool);
		options.baseURI = StaticString(scriptName->start->data, scriptName->size);
	}

	fillPoolOptionsFromConfigCaches(options, req->pool, req->config);

	const LString *appType = secureHeaders.lookup("!~PASSENGER_APP_TYPE");
	if (appType == NULL || appType->size == 0) {
		const LString *appStartCommand = secureHeaders.lookup("!~PASSENGER_APP_START_COMMAND");
		if (appStartCommand == NULL || appStartCommand->size == 0) {
			AppTypeDetector::Detector detector(*wrapperRegistry);
			AppTypeDetector::Detector::Result result = detector.checkAppRoot(options.appRoot);
			if (result.isNull()) {
				disconnectWithError(&client, "client did not send a recognized !~PASSENGER_APP_TYPE header");
				return;
			}
			options.appType = result.wrapperRegistryEntry->language;
		} else {
			fillPoolOption(req, options.appStartCommand, "!~PASSENGER_APP_START_COMMAND");
		}
	} else {
		fillPoolOption(req, options.appType, "!~PASSENGER_APP_TYPE");
	}

	options.appGroupName = appGroupName;

	fillPoolOption(req, options.appLogFile, "!~PASSENGER_APP_LOG_FILE");
	fillPoolOption(req, options.environment, "!~PASSENGER_APP_ENV");
	fillPoolOption(req, options.ruby, "!~PASSENGER_RUBY");
	fillPoolOption(req, options.python, "!~PASSENGER_PYTHON");
	fillPoolOption(req, options.nodejs, "!~PASSENGER_NODEJS");
	fillPoolOption(req, options.meteorAppSettings, "!~PASSENGER_METEOR_APP_SETTINGS");
	fillPoolOption(req, options.user, "!~PASSENGER_USER");
	fillPoolOption(req, options.group, "!~PASSENGER_GROUP");
	fillPoolOption(req, options.minProcesses, "!~PASSENGER_MIN_PROCESSES");
	fillPoolOption(req, options.spawnMethod, "!~PASSENGER_SPAWN_METHOD");
	fillPoolOption(req, options.appStartCommand, "!~PASSENGER_APP_START_COMMAND");
	fillPoolOptionSecToMsec(req, options.startTimeout, "!~PASSENGER_START_TIMEOUT");
	fillPoolOption(req, options.maxPreloaderIdleTime, "!~PASSENGER_MAX_PRELOADER_IDLE_TIME");
	fillPoolOption(req, options.maxRequestQueueSize, "!~PASSENGER_MAX_REQUEST_QUEUE_SIZE");
	fillPoolOption(req, options.abortWebsocketsOnProcessShutdown, "!~PASSENGER_ABORT_WEBSOCKETS_ON_PROCESS_SHUTDOWN");
	fillPoolOption(req, options.forceMaxConcurrentRequestsPerProcess, "!~PASSENGER_FORCE_MAX_CONCURRENT_REQUESTS_PER_PROCESS");
	fillPoolOption(req, options.restartDir, "!~PASSENGER_RESTART_DIR");
	fillPoolOption(req, options.startupFile, "!~PASSENGER_STARTUP_FILE");
	fillPoolOption(req, options.loadShellEnvvars, "!~PASSENGER_LOAD_SHELL_ENVVARS");
	fillPoolOption(req, options.fileDescriptorUlimit, "!~PASSENGER_APP_FILE_DESCRIPTOR_ULIMIT");
	fillPoolOption(req, options.raiseInternalError, "!~PASSENGER_RAISE_INTERNAL_ERROR");
	fillPoolOption(req, options.lveMinUid, "!~PASSENGER_LVE_MIN_UID");

	// maxProcesses is configured per-application by the (Enterprise) maxInstances option (and thus passed
	// via request headers). In OSS the max processes can also be configured, but on a global level
	// (i.e. the same for all apps) using the maxInstancesPerApp option. As an easy implementation shortcut
	// we apply maxInstancesPerApp to options.maxProcesses (which can be overridden by Enterprise).
	options.maxProcesses = mainConfig.maxInstancesPerApp;
	/******************/

	boost::shared_ptr<Options> optionsCopy = boost::make_shared<Options>(options);
	optionsCopy->persist(options);
	optionsCopy->clearPerRequestFields();
	poolOptionsCache.insert(options.getAppGroupName(), optionsCopy);
}

void
Controller::setStickySessionId(Client *client, Request *req) {
	if (req->stickySession) {
		// TODO: This is not entirely correct. Clients MAY send multiple Cookie
		// headers, although this is in practice extremely rare.
		// http://stackoverflow.com/questions/16305814/are-multiple-cookie-headers-allowed-in-an-http-request
		const LString *cookieHeader = req->headers.lookup(HTTP_COOKIE);
		if (cookieHeader != NULL && cookieHeader->size > 0) {
			const LString *cookieName = getStickySessionCookieName(req);
			vector< pair<StaticString, StaticString> > cookies;
			pair<StaticString, StaticString> cookie;

			parseCookieHeader(req->pool, cookieHeader, cookies);
			foreach (cookie, cookies) {
				if (psg_lstr_cmp(cookieName, cookie.first)) {
					// This cookie matches the one we're looking for.
					req->options.stickySessionId = stringToUint(cookie.second);
					return;
				}
			}
		}
	}
}

const LString *
Controller::getStickySessionCookieName(Request *req) {
	const LString *value = req->headers.lookup(PASSENGER_STICKY_SESSIONS_COOKIE_NAME);
	if (value == NULL || value->size == 0) {
		return psg_lstr_create(req->pool,
			req->config->defaultStickySessionsCookieName);
	} else {
		return value;
	}
}


/****************************
 *
 * Protected methods
 *
 ****************************/


void
Controller::onRequestBegin(Client *client, Request *req) {
	ParentClass::onRequestBegin(client, req);

	CC_BENCHMARK_POINT(client, req, BM_AFTER_ACCEPT);

	{
		// Perform hash table operations as close to header parsing as possible,
		// and localize them as much as possible, for better CPU caching.
		RequestAnalysis analysis;
		analysis.flags = req->secureHeaders.lookup(FLAGS);
		analysis.appGroupNameCell = mainConfig.singleAppMode
			? NULL
			: req->secureHeaders.lookupCell(PASSENGER_APP_GROUP_NAME);
		req->stickySession = getBoolOption(req, PASSENGER_STICKY_SESSIONS,
			mainConfig.defaultStickySessions);
		req->host = req->headers.lookup(HTTP_HOST);

		/***************/
		/***************/

		SKC_TRACE(client, 2, "Initiating request");
		req->startedAt = ev_now(getLoop());
		req->bodyChannel.stop();

		initializeFlags(client, req, analysis);
		if (respondFromTurboCache(client, req)) {
			return;
		}
		initializePoolOptions(client, req, analysis);
		if (req->ended()) {
			return;
		}
		if (req->ended()) {
			return;
		}
		setStickySessionId(client, req);
	}

	if (!req->hasBody() || !req->requestBodyBuffering) {
		req->requestBodyBuffering = false;
		checkoutSession(client, req);
	} else {
		beginBufferingBody(client, req);
	}
}


} // namespace Core
} // namespace Passenger
