/*
 * Copyright 2009-2017 Alibaba Cloud All rights reserved.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <alibabacloud/core/InstanceProfileCredentialsProvider.h>
#include <chrono>
#include <iomanip>
#include <chrono>
#include <mutex>
#include <sstream>
#include <json/json.h>
#include "EcsMetadataFetcher.h"

using namespace AlibabaCloud;

InstanceProfileCredentialsProvider::InstanceProfileCredentialsProvider(const std::string & roleName, int durationSeconds):
	CredentialsProvider(),
	durationSeconds_(durationSeconds),
	cachedMutex_(),
	cachedCredentials_("", ""),
	fetcher_(new EcsMetadataFetcher),
	expiry_()
{
	fetcher_->setRoleName(roleName);
}

InstanceProfileCredentialsProvider::~InstanceProfileCredentialsProvider()
{
	delete fetcher_;
}

std::string InstanceProfileCredentialsProvider::roleName()const
{
	return fetcher_->roleName();
}

Credentials InstanceProfileCredentialsProvider::getCredentials()
{
	loadCredentials();
	std::lock_guard<std::mutex> locker(cachedMutex_);
	return cachedCredentials_;
}

bool InstanceProfileCredentialsProvider::checkExpiry()const
{
	auto now = std::chrono::system_clock::now();
	auto diff = std::chrono::duration_cast<std::chrono::seconds>(now - expiry_).count();

	return (diff > 0 - 60);
}

void InstanceProfileCredentialsProvider::loadCredentials()
{
	if (checkExpiry())
	{
		std::lock_guard<std::mutex> locker(cachedMutex_);
		if (checkExpiry())
		{
			auto outcome = fetcher_->getMetadata();
			Json::Value value;
			Json::Reader reader;
			if (reader.parse(outcome, value))
			{
				if (value["Code"] == nullptr
					&&value["AccessKeyId"] == nullptr
					&&value["AccessKeySecret"] == nullptr
					&&value["SecurityToken"] == nullptr
					&&value["Expiration"] == nullptr)
				{
					cachedCredentials_ = Credentials("","");
					return;
				}

				auto code = value["Code"].asString();
				auto accessKeyId = value["AccessKeyId"].asString();
				auto accessKeySecret = value["AccessKeySecret"].asString();
				auto securityToken = value["SecurityToken"].asString();
				auto expiration = value["Expiration"].asString();

				cachedCredentials_ = Credentials(accessKeyId,
					accessKeySecret,
					securityToken);

				std::tm tm = {};
#if defined(__GNUG__) && __GNUC__ < 5
				strptime(expiration.c_str(), "%Y-%m-%dT%H:%M:%SZ", &tm);
#else			
				std::stringstream ss(expiration);
				ss >> std::get_time(&tm, "%Y-%m-%dT%H:%M:%SZ");
#endif
				expiry_ = std::chrono::system_clock::from_time_t(std::mktime(&tm));
			}
		}
	}
}