/*
	Copyright (c)  2013, 2014 IOnU Security Inc. All rights reserved. Copyright (c) 2015, 2016 Sequence Logic, Inc.
	Created August 2013 by Kendrick Webster

	K2Daemon/MongoDB.cpp - implementation for MongoDB.h
*/
#include "global.h"
#include "MongoDB.h"

#include <sstream>

// module static (local) data
namespace
{
	mongoc_client_t *connection = NULL;
	std::string mongoServer;
	bool isConnected = false;
	bool isDown = false; // true during transient failures (i.e. replica set primary goes down, new primary not yet elected)
	CStopWatch stopwatch;
}

success_t MongoDB::Connect(const char* host, int port)
{
	logprintf(Log::informational, "Connecting to MongoDB host %s port %d", host, port);
	std::stringstream hostURI;
	hostURI << "mongodb://" << host << ":" << port;
	mongoServer = hostURI.str();
	connection = mongoc_client_new(mongoServer.c_str());
	if (connection == NULL)
	{
        isConnected = false;
		logprintf(Log::error, "mongo_client (connect): \"mongodb://%s:%d\"", host, port);
		return FAILURE;
	}
	isConnected = true;
    isDown = false;
	logprintf(Log::debug, "connected to MongoDB");
	return SUCCESS;
}

success_t MongoDB::ConnectReplica(const std::string& replica_set_name, const std::string& hosts)
{
	if (isConnected)
		Disconnect();
    logprintf(Log::informational, "Connecting to MongoDB replica set %s", replica_set_name.c_str());

    std::stringstream repSetURI;
    repSetURI << "mongodb://" << hosts << "/?replicaSet=" << replica_set_name;
    mongoServer = repSetURI.str();
    connection = mongoc_client_new(mongoServer.c_str());
    if (connection == NULL)
    {
		logprintf(Log::error, "Cannot connect to replica set: \"mongodb://%s/?replicaSet=%s\"", hosts.c_str(), replica_set_name.c_str());
        isConnected = false;
		return FAILURE;
	}
	isConnected = true;
    isDown = false;
	logprintf(Log::debug, "connected to MongoDB");
	return SUCCESS;
}

void MongoDB::Disconnect(void)
{
	if (isConnected)
	{
		logprintf(Log::debug, "logging out of MongoDB");
		mongoc_client_destroy(connection);
		isConnected = false;
		connection = NULL;
	}
}

success_t MongoDB::Reconnect(void)
{
    if (isConnected)
    {
        logprintf(Log::informational, "Re-connecting to MongoDB");

        // It seems that the new C driver doesn't have a "reconnect" function!!!
		Disconnect();
		connection = mongoc_client_new(mongoServer.c_str());

		if (connection == NULL)
		{
			isDown = true;
			stopwatch.Reset();
			logprintf(Log::error, "mongo_reconnect");
			return FAILURE;
		}
    }
    return FAILURE;
}

mongoc_client_t* MongoDB::GetConnection(void)
{
	if (isDown || !isConnected)
	{
		return NULL;
	}
	return connection;
}

bool MongoDB::IsTemporaryOutage(void)
{
    return isDown && isConnected;
}

const char* MongoDB::ErrorString(mongoc_error_code_t e)
{
	static char buf[48];
	switch (e)
	{
	//case MONGO_CONN_SUCCESS:          return "Connection success!";
	//case MONGO_CONN_NO_SOCKET:        return "Could not create a socket.";
	case MONGOC_ERROR_STREAM_CONNECT:             return "An error occured while calling connect().";
	case MONGOC_ERROR_STREAM_NAME_RESOLUTION:        return "An error occured while calling getaddrinfo().";
	//case MONGO_CONN_NOT_MASTER:       return "Warning: connected to a non-master node (read-only).";
	//case MONGO_CONN_BAD_SET_NAME:     return "Given rs name doesn't match this replica set.";
	//case MONGO_CONN_NO_PRIMARY:       return "Can't find primary in replica set. Connection closed.";

	//case MONGO_IO_ERROR:              return "An error occurred while reading or writing on the socket.";
	//case MONGOC_ERROR_STREAM_SOCKET:          return "Other socket error.";
	//case MONGO_READ_SIZE_ERROR:       return "The response is not the expected length.";
	//case MONGO_COMMAND_FAILED:        return "The command returned with 'ok' value of 0.";
	//case MONGO_WRITE_ERROR:           return "Write with given write_concern returned an error.";
	//case MONGO_NS_INVALID:            return "The name for the ns (database or collection) is invalid.";
	//case MONGO_BSON_INVALID:          return "BSON not valid for the specified op.";
	//case MONGO_BSON_NOT_FINISHED:     return "BSON object has not been finished.";
	//case MONGO_BSON_TOO_LARGE:        return "BSON object exceeds max BSON size.";
	//case MONGO_WRITE_CONCERN_INVALID: return "Supplied write concern object is invalid.";

	default:
		snprintf(buf, sizeof(buf), "Unknown MongoDB error, code %d", static_cast<int>(e));
		return buf;
	}
}

void MongoDB::Timer(void)
{
    if (isDown && (MONGODB_RECONNECT_DELAY_MILLISECONDS <= stopwatch.Milliseconds()))
    {
        logprintf(Log::informational, "timer initiated MongoDB reconnect");
        Reconnect();
    }
}