/**
 * @file llappcorehttp.cpp
 * @brief 
 *
 * $LicenseInfo:firstyear=2012&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2012-2013, Linden Research, Inc.
 *
 * This library 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;
 * version 2.1 of the License only.
 *
 * This library 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 library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#include "llviewerprecompiledheaders.h"

#include "llappcorehttp.h"

#include "llappviewer.h"
#include "llviewercontrol.h"


// Here is where we begin to get our connection usage under control.
// This establishes llcorehttp policy classes that, among other
// things, limit the maximum number of connections to outside
// services.  Each of the entries below maps to a policy class and
// has a limit, sometimes configurable, of how many connections can
// be open at a time.

const F64 LLAppCoreHttp::MAX_THREAD_WAIT_TIME(10.0);
static const struct
{
	LLAppCoreHttp::EAppPolicy	mPolicy;
	U32							mDefault;
	U32							mMin;
	U32							mMax;
	U32							mRate;
	std::string					mKey;
	const char *				mUsage;
} init_data[] =					//  Default and dynamic values for classes
{
	{
		LLAppCoreHttp::AP_TEXTURE,			8,		1,		12,		0,
		"TextureFetchConcurrency",
		"texture fetch"
	},
	{
		LLAppCoreHttp::AP_MESH1,			32,		1,		128,	100,
		"MeshMaxConcurrentRequests",
		"mesh fetch"
	},
	{
		LLAppCoreHttp::AP_MESH2,			8,		1,		32,		100,
		"Mesh2MaxConcurrentRequests",
		"mesh2 fetch"
	},
	{
		LLAppCoreHttp::AP_LARGE_MESH,		2,		1,		8,		0,
		"",
		"large mesh fetch"
	},
	{
		LLAppCoreHttp::AP_UPLOADS,			2,		1,		8,		0,
		"",
		"asset upload"
	}
};

static void setting_changed();


LLAppCoreHttp::LLAppCoreHttp()
	: mRequest(NULL),
	  mStopHandle(LLCORE_HTTP_HANDLE_INVALID),
	  mStopRequested(0.0),
	  mStopped(false)
{
	for (int i(0); i < LL_ARRAY_SIZE(mPolicies); ++i)
	{
		mPolicies[i] = LLCore::HttpRequest::DEFAULT_POLICY_ID;
		mSettings[i] = 0U;
	}
}


LLAppCoreHttp::~LLAppCoreHttp()
{
	delete mRequest;
	mRequest = NULL;
}


void LLAppCoreHttp::init()
{
	LLCore::HttpStatus status = LLCore::HttpRequest::createService();
	if (! status)
	{
		LL_ERRS("Init") << "Failed to initialize HTTP services.  Reason:  " << status.toString()
						<< LL_ENDL;
	}

	// Point to our certs or SSH/https: will fail on connect
	status = LLCore::HttpRequest::setStaticPolicyOption(LLCore::HttpRequest::PO_CA_FILE,
														LLCore::HttpRequest::GLOBAL_POLICY_ID,
														gDirUtilp->getCAFile(), NULL);
	if (! status)
	{
		LL_ERRS("Init") << "Failed to set CA File for HTTP services.  Reason:  " << status.toString()
						<< LL_ENDL;
	}

	// Establish HTTP Proxy, if desired.
	status = LLCore::HttpRequest::setStaticPolicyOption(LLCore::HttpRequest::PO_LLPROXY,
														LLCore::HttpRequest::GLOBAL_POLICY_ID,
														1, NULL);
	if (! status)
	{
		LL_WARNS("Init") << "Failed to set HTTP proxy for HTTP services.  Reason:  " << status.toString()
						 << LL_ENDL;
	}

	// Tracing levels for library & libcurl (note that 2 & 3 are beyond spammy):
	// 0 - None
	// 1 - Basic start, stop simple transitions
	// 2 - libcurl CURLOPT_VERBOSE mode with brief lines
	// 3 - with partial data content
	static const std::string http_trace("QAModeHttpTrace");
	if (gSavedSettings.controlExists(http_trace))
	{
		long trace_level(0L);
		trace_level = long(gSavedSettings.getU32(http_trace));
		status = LLCore::HttpRequest::setStaticPolicyOption(LLCore::HttpRequest::PO_TRACE,
															LLCore::HttpRequest::GLOBAL_POLICY_ID,
															trace_level, NULL);
	}
	
	// Setup default policy and constrain if directed to
	mPolicies[AP_DEFAULT] = LLCore::HttpRequest::DEFAULT_POLICY_ID;

	// Setup additional policies based on table and some special rules
	for (int i(0); i < LL_ARRAY_SIZE(init_data); ++i)
	{
		const EAppPolicy policy(init_data[i].mPolicy);

		// Create a policy class but use default for texture for now.
		// This also has the side-effect of initializing the default
		// class to desired values.
		if (AP_TEXTURE == policy)
		{
			mPolicies[policy] = mPolicies[AP_DEFAULT];
		}
		else
		{
			mPolicies[policy] = LLCore::HttpRequest::createPolicyClass();
			if (! mPolicies[policy])
			{
				// Use default policy (but don't accidentally modify default)
				LL_WARNS("Init") << "Failed to create HTTP policy class for " << init_data[i].mUsage
								 << ".  Using default policy."
								 << LL_ENDL;
				mPolicies[policy] = mPolicies[AP_DEFAULT];
				continue;
			}
		}
	}

	// Need a request object to handle dynamic options before setting them
	mRequest = new LLCore::HttpRequest;

	// Apply initial settings
	refreshSettings(true);
	
	// Kick the thread
	status = LLCore::HttpRequest::startThread();
	if (! status)
	{
		LL_ERRS("Init") << "Failed to start HTTP servicing thread.  Reason:  " << status.toString()
						<< LL_ENDL;
	}

	// Register signals for settings and state changes
	for (int i(0); i < LL_ARRAY_SIZE(init_data); ++i)
	{
		if (! init_data[i].mKey.empty() && gSavedSettings.controlExists(init_data[i].mKey))
		{
			LLPointer<LLControlVariable> cntrl_ptr = gSavedSettings.getControl(init_data[i].mKey);
			if (cntrl_ptr.isNull())
			{
				LL_WARNS("Init") << "Unable to set signal on global setting '" << init_data[i].mKey
								 << "'" << LL_ENDL;
			}
			else
			{
				mSettingsSignal[i] = cntrl_ptr->getCommitSignal()->connect(boost::bind(&setting_changed));
			}
		}
	}
}


void setting_changed()
{
	LLAppViewer::instance()->getAppCoreHttp().refreshSettings(false);
}


void LLAppCoreHttp::requestStop()
{
	llassert_always(mRequest);

	mStopHandle = mRequest->requestStopThread(this);
	if (LLCORE_HTTP_HANDLE_INVALID != mStopHandle)
	{
		mStopRequested = LLTimer::getTotalSeconds();
	}
}


void LLAppCoreHttp::cleanup()
{
	if (LLCORE_HTTP_HANDLE_INVALID == mStopHandle)
	{
		// Should have been started already...
		requestStop();
	}
	
	if (LLCORE_HTTP_HANDLE_INVALID == mStopHandle)
	{
		LL_WARNS("Cleanup") << "Attempting to cleanup HTTP services without thread shutdown"
							<< LL_ENDL;
	}
	else
	{
		while (! mStopped && LLTimer::getTotalSeconds() < (mStopRequested + MAX_THREAD_WAIT_TIME))
		{
			mRequest->update(200000);
			ms_sleep(50);
		}
		if (! mStopped)
		{
			LL_WARNS("Cleanup") << "Attempting to cleanup HTTP services with thread shutdown incomplete"
								<< LL_ENDL;
		}
	}

	for (int i(0); i < LL_ARRAY_SIZE(init_data); ++i)
	{
		mSettingsSignal[i].disconnect();
	}
	
	delete mRequest;
	mRequest = NULL;

	LLCore::HttpStatus status = LLCore::HttpRequest::destroyService();
	if (! status)
	{
		LL_WARNS("Cleanup") << "Failed to shutdown HTTP services, continuing.  Reason:  "
							<< status.toString()
							<< LL_ENDL;
	}
}

void LLAppCoreHttp::refreshSettings(bool initial)
{
	LLCore::HttpStatus status;
	
	for (int i(0); i < LL_ARRAY_SIZE(init_data); ++i)
	{
		const EAppPolicy policy(init_data[i].mPolicy);

		// Set any desired throttle
		if (initial && init_data[i].mRate)
		{
			// Init-time only, can use the static setters here
			status = LLCore::HttpRequest::setStaticPolicyOption(LLCore::HttpRequest::PO_THROTTLE_RATE,
																mPolicies[policy],
																init_data[i].mRate,
																NULL);
			if (! status)
			{
				LL_WARNS("Init") << "Unable to set " << init_data[i].mUsage
								 << " throttle rate.  Reason:  " << status.toString()
								 << LL_ENDL;
			}
		}

		// Get target connection concurrency value
		U32 setting(init_data[i].mDefault);
		if (! init_data[i].mKey.empty() && gSavedSettings.controlExists(init_data[i].mKey))
		{
			U32 new_setting(gSavedSettings.getU32(init_data[i].mKey));
			if (new_setting)
			{
				// Treat zero settings as an ask for default
				setting = llclamp(new_setting, init_data[i].mMin, init_data[i].mMax);
			}
		}

		if (! initial && setting == mSettings[policy])
		{
			// Unchanged, try next setting
			continue;
		}
		
		// Set it and report
		// *TODO:  These are intended to be per-host limits when we can
		// support that in llcorehttp/libcurl.
		LLCore::HttpHandle handle;
		handle = mRequest->setPolicyOption(LLCore::HttpRequest::PO_CONNECTION_LIMIT,
										   mPolicies[policy],
										   setting, NULL);
		if (LLCORE_HTTP_HANDLE_INVALID == handle)
		{
			status = mRequest->getStatus();
			LL_WARNS("Init") << "Unable to set " << init_data[i].mUsage
							 << " concurrency.  Reason:  " << status.toString()
							 << LL_ENDL;
		}
		else
		{
			LL_DEBUGS("Init") << "Changed " << init_data[i].mUsage
							  << " concurrency.  New value:  " << setting
							  << LL_ENDL;
			mSettings[policy] = setting;
			if (initial && setting != init_data[i].mDefault)
			{
				LL_INFOS("Init") << "Application settings overriding default " << init_data[i].mUsage
								 << " concurrency.  New value:  " << setting
								 << LL_ENDL;
			}
		}
	}
}


void LLAppCoreHttp::onCompleted(LLCore::HttpHandle, LLCore::HttpResponse *)
{
	mStopped = true;
}