#include "ua_server.h"
#include "ua_services.h"
#include "ua_statuscodes.h"
#include "ua_namespace_0.h"
#include "ua_securechannel_manager.h"
#include "ua_session_manager.h"
#include "ua_util.h"

static UA_StatusCode UA_ByteStringArray_deleteMembers(UA_ByteStringArray *stringarray) {
    if(!stringarray)
        return UA_STATUSCODE_BADINTERNALERROR;
    for(UA_UInt32 i = 0;i < stringarray->stringsSize;i++)
        UA_String_deleteMembers(&stringarray->strings[i]);
    return UA_STATUSCODE_GOOD;
}

static void processHello(UA_Connection *connection, const UA_ByteString *msg,
                         UA_UInt32 *pos) {
    UA_TcpHelloMessage helloMessage;
    if(UA_TcpHelloMessage_decodeBinary(msg, pos, &helloMessage) != UA_STATUSCODE_GOOD) {
        connection->close(connection->callbackHandle);
        return;
    }
    connection->remoteConf.maxChunkCount   = helloMessage.maxChunkCount;
    connection->remoteConf.maxMessageSize  = helloMessage.maxMessageSize;
    connection->remoteConf.protocolVersion = helloMessage.protocolVersion;
    connection->remoteConf.recvBufferSize  = helloMessage.receiveBufferSize;
    connection->remoteConf.sendBufferSize  = helloMessage.sendBufferSize;

    connection->state = UA_CONNECTION_ESTABLISHED;

    // build acknowledge response
    UA_TcpAcknowledgeMessage ackMessage;
    ackMessage.protocolVersion   = connection->localConf.protocolVersion;
    ackMessage.receiveBufferSize = connection->localConf.recvBufferSize;
    ackMessage.sendBufferSize    = connection->localConf.sendBufferSize;
    ackMessage.maxMessageSize    = connection->localConf.maxMessageSize;
    ackMessage.maxChunkCount     = connection->localConf.maxChunkCount;

    UA_TcpMessageHeader ackHeader;
    ackHeader.messageType = UA_MESSAGETYPE_ACK;
    ackHeader.isFinal     = 'F';
    ackHeader.messageSize = UA_TcpAcknowledgeMessage_calcSizeBinary(&ackMessage) +
                            UA_TcpMessageHeader_calcSizeBinary(&ackHeader);

    UA_ByteString ack_msg;
    UA_UInt32 tmpPos = 0;
    UA_ByteString_newMembers(&ack_msg, ackHeader.messageSize);
    UA_TcpMessageHeader_encodeBinary(&ackHeader, &ack_msg, &tmpPos);
    UA_TcpAcknowledgeMessage_encodeBinary(&ackMessage, &ack_msg, &tmpPos);
    UA_ByteStringArray answer_buf = { .stringsSize = 1, .strings = &ack_msg };
    connection->write(connection->callbackHandle, answer_buf); // the string is freed internall in the (asynchronous) write
    UA_TcpHelloMessage_deleteMembers(&helloMessage);
}

static void processOpen(UA_Connection *connection, UA_Server *server,
                        const UA_ByteString *msg, UA_UInt32 *pos) {
    if(connection->state != UA_CONNECTION_ESTABLISHED) {
        // was hello exchanged before?
        if(connection->state == UA_CONNECTION_OPENING)
            connection->close(connection->callbackHandle);
        return;
    }

    UA_UInt32 secureChannelId;
    UA_UInt32_decodeBinary(msg, pos, &secureChannelId);

    UA_AsymmetricAlgorithmSecurityHeader asymHeader;
    UA_AsymmetricAlgorithmSecurityHeader_decodeBinary(msg, pos, &asymHeader);

    UA_SequenceHeader seqHeader;
    UA_SequenceHeader_decodeBinary(msg, pos, &seqHeader);

    UA_ExpandedNodeId requestType;
    UA_ExpandedNodeId_decodeBinary(msg, pos, &requestType);

    if(requestType.nodeId.identifier.numeric != 446) {
        // todo: handle error
    }

    UA_OpenSecureChannelRequest r;
    UA_OpenSecureChannelRequest_decodeBinary(msg, pos, &r);

    // perform request
    UA_OpenSecureChannelResponse p;
    UA_OpenSecureChannelResponse_init(&p);
    Service_OpenSecureChannel(server, connection, &r, &p);

    // response
    UA_TcpMessageHeader respHeader;
    respHeader.messageType = UA_MESSAGETYPE_OPN;
    respHeader.isFinal     = 'F';
    respHeader.messageSize = 8+4; //header + securechannelid

    UA_ExpandedNodeId responseType;
    NS0EXPANDEDNODEID(responseType, 449);

    respHeader.messageSize += UA_AsymmetricAlgorithmSecurityHeader_calcSizeBinary(&asymHeader);
    respHeader.messageSize += UA_SequenceHeader_calcSizeBinary(&seqHeader);
    respHeader.messageSize += UA_ExpandedNodeId_calcSizeBinary(&responseType);
    respHeader.messageSize += UA_OpenSecureChannelResponse_calcSizeBinary(&p);

    UA_ByteString resp_msg;
    UA_UInt32 tmpPos = 0;
    UA_ByteString_newMembers(&resp_msg, respHeader.messageSize);
    UA_TcpMessageHeader_encodeBinary(&respHeader, &resp_msg, &tmpPos);
    UA_UInt32_encodeBinary(&p.securityToken.channelId, &resp_msg, &tmpPos);
    UA_AsymmetricAlgorithmSecurityHeader_encodeBinary(&asymHeader, &resp_msg, &tmpPos); // just mirror back
    UA_SequenceHeader_encodeBinary(&seqHeader, &resp_msg, &tmpPos); // just mirror back
    UA_ExpandedNodeId_encodeBinary(&responseType, &resp_msg, &tmpPos);
    UA_OpenSecureChannelResponse_encodeBinary(&p, &resp_msg, &tmpPos);

    UA_OpenSecureChannelRequest_deleteMembers(&r);
    UA_OpenSecureChannelResponse_deleteMembers(&p);
    UA_AsymmetricAlgorithmSecurityHeader_deleteMembers(&asymHeader);
    
    UA_ByteStringArray answer_buf = { .stringsSize = 1, .strings = &resp_msg };
    connection->write(connection->callbackHandle, answer_buf);
}

static void init_response_header(const UA_RequestHeader *p, UA_ResponseHeader *r) {
    r->requestHandle   = p->requestHandle;
    r->serviceResult   = UA_STATUSCODE_GOOD;
    r->stringTableSize = 0;
    r->timestamp       = UA_DateTime_now();
}

#define CHECK_PROCESS(CODE, CLEANUP) \
    do { if(CODE != UA_STATUSCODE_GOOD) {    \
            CLEANUP;                 \
            return;                  \
        } } while(0)

#define INVOKE_SERVICE(TYPE) do {                                                                         \
        UA_##TYPE##Request p;                                                                             \
        UA_##TYPE##Response r;                                                                            \
        CHECK_PROCESS(UA_##TYPE##Request_decodeBinary(msg, pos, &p),; );                                  \
        UA_##TYPE##Response_init(&r);                                                                     \
        init_response_header(&p.requestHeader, &r.responseHeader);                                        \
        DBG_VERBOSE(printf("Invoke Service: %s\n", # TYPE));                                              \
        Service_##TYPE(server, channel->session, &p, &r);                                                 \
        DBG_VERBOSE(printf("Finished Service: %s\n", # TYPE));                                            \
        UA_ByteString_newMembers(message, UA_##TYPE##Response_calcSizeBinary(&r)); \
        UA_##TYPE##Response_encodeBinary(&r, message, &sendOffset);     \
        UA_##TYPE##Request_deleteMembers(&p);                                                             \
        UA_##TYPE##Response_deleteMembers(&r);                                                            \
        responseType = requestType.nodeId.identifier.numeric + 3;                                         \
} while(0)

static void processMessage(UA_Connection *connection, UA_Server *server, const UA_ByteString *msg, UA_UInt32 *pos) {
    // 1) Read in the securechannel
    UA_UInt32 secureChannelId;
    UA_UInt32_decodeBinary(msg, pos, &secureChannelId);

    UA_SecureChannel *channel;
    UA_SecureChannelManager_get(server->secureChannelManager, secureChannelId, &channel);

    // 2) Read the security header
    UA_UInt32 tokenId;
    UA_UInt32_decodeBinary(msg, pos, &tokenId);
    UA_SequenceHeader sequenceHeader;
    CHECK_PROCESS(UA_SequenceHeader_decodeBinary(msg, pos, &sequenceHeader),; );

    channel->sequenceNumber = sequenceHeader.sequenceNumber;
    channel->requestId = sequenceHeader.requestId;
    // todo
    //UA_SecureChannel_checkSequenceNumber(channel,sequenceHeader.sequenceNumber);
    //UA_SecureChannel_checkRequestId(channel,sequenceHeader.requestId);

    // 3) Read the nodeid of the request
    UA_ExpandedNodeId requestType;
    CHECK_PROCESS(UA_ExpandedNodeId_decodeBinary(msg, pos, &requestType),; );
    if(requestType.nodeId.identifierType != UA_NODEIDTYPE_NUMERIC) {
        UA_ExpandedNodeId_deleteMembers(&requestType); // if the nodeidtype is numeric, we do not have to free anything
        return;
    }

    // 4) process the request
    UA_ByteString responseBufs[2]; // 0->header, 1->response payload
    UA_UInt32 responseType;
    UA_ByteString *header = &responseBufs[0];
    UA_ByteString *message = &responseBufs[1];

    UA_UInt32 sendOffset = 0;
    //subtract UA_ENCODINGOFFSET_BINARY for binary encoding
    switch(requestType.nodeId.identifier.numeric - UA_ENCODINGOFFSET_BINARY) {
    case UA_GETENDPOINTSREQUEST_NS0: {
        UA_GetEndpointsRequest  p;
        UA_GetEndpointsResponse r;
        CHECK_PROCESS(UA_GetEndpointsRequest_decodeBinary(msg, pos, &p),; );
        UA_GetEndpointsResponse_init(&r);
        init_response_header(&p.requestHeader, &r.responseHeader);
        Service_GetEndpoints(server, &p, &r);
        UA_ByteString_newMembers(message, UA_GetEndpointsResponse_calcSizeBinary(&r));
        UA_GetEndpointsResponse_encodeBinary(&r, message, &sendOffset);
        UA_GetEndpointsRequest_deleteMembers(&p);
        UA_GetEndpointsResponse_deleteMembers(&r);
        responseType = requestType.nodeId.identifier.numeric + 3;
        break;
    }

    case UA_CREATESESSIONREQUEST_NS0: {
        UA_CreateSessionRequest  p;
        UA_CreateSessionResponse r;
        CHECK_PROCESS(UA_CreateSessionRequest_decodeBinary(msg, pos, &p),; );
        UA_CreateSessionResponse_init(&r);
        init_response_header(&p.requestHeader, &r.responseHeader);
        Service_CreateSession(server, channel,  &p, &r);
        UA_ByteString_newMembers(message, UA_CreateSessionResponse_calcSizeBinary(&r));
        UA_CreateSessionResponse_encodeBinary(&r, message, &sendOffset);
        UA_CreateSessionRequest_deleteMembers(&p);
        UA_CreateSessionResponse_deleteMembers(&r);
        responseType = requestType.nodeId.identifier.numeric + 3;
        break;
    }

    case UA_ACTIVATESESSIONREQUEST_NS0: {
        UA_ActivateSessionRequest  p;
        UA_ActivateSessionResponse r;
        CHECK_PROCESS(UA_ActivateSessionRequest_decodeBinary(msg, pos, &p),; );
        UA_ActivateSessionResponse_init(&r);
        init_response_header(&p.requestHeader, &r.responseHeader);

        Service_ActivateSession(server, channel,  &p, &r);
        UA_ByteString_newMembers(message, UA_ActivateSessionResponse_calcSizeBinary(&r));
        UA_ActivateSessionResponse_encodeBinary(&r, message, &sendOffset);
        UA_ActivateSessionRequest_deleteMembers(&p);
        UA_ActivateSessionResponse_deleteMembers(&r);
        responseType = requestType.nodeId.identifier.numeric + 3;
    }
        break;

    case UA_CLOSESESSIONREQUEST_NS0: {
        UA_CloseSessionRequest  p;
        UA_CloseSessionResponse r;
        CHECK_PROCESS(UA_CloseSessionRequest_decodeBinary(msg, pos, &p),; );
        UA_CloseSessionResponse_init(&r);
        init_response_header(&p.requestHeader, &r.responseHeader);

        Service_CloseSession(server, &p, &r);
        UA_ByteString_newMembers(message, UA_CloseSessionResponse_calcSizeBinary(&r));
        UA_CloseSessionResponse_encodeBinary(&r, message, &sendOffset);
        UA_CloseSessionRequest_deleteMembers(&p);
        UA_CloseSessionResponse_deleteMembers(&r);
        responseType = requestType.nodeId.identifier.numeric + 3;
    }
    break;

    case UA_READREQUEST_NS0:
        INVOKE_SERVICE(Read);
        break;

    case UA_WRITEREQUEST_NS0:
        INVOKE_SERVICE(Write);
        break;

    case UA_BROWSEREQUEST_NS0:
        INVOKE_SERVICE(Browse);
        break;

    /* case UA_CREATESUBSCRIPTIONREQUEST_NS0: */
    /*     INVOKE_SERVICE(CreateSubscription); */
    /*     break; */

    case UA_TRANSLATEBROWSEPATHSTONODEIDSREQUEST_NS0:
        INVOKE_SERVICE(TranslateBrowsePathsToNodeIds);
        break;

    /* case UA_PUBLISHREQUEST_NS0: */
    /*     INVOKE_SERVICE(Publish); */
    /*     break; */

    /* case UA_CREATEMONITOREDITEMSREQUEST_NS0: */
    /*     INVOKE_SERVICE(CreateMonitoredItems); */
    /*     break; */

    /* case UA_SETPUBLISHINGMODEREQUEST_NS0: */
    /*     INVOKE_SERVICE(SetPublishingMode); */
    /*     break; */

    default: {
        printf("SL_processMessage - unknown request, namespace=%d, request=%d\n",
               requestType.nodeId.namespaceIndex, requestType.nodeId.identifier.numeric);
        UA_RequestHeader  p;
        UA_ResponseHeader r;
        CHECK_PROCESS(UA_RequestHeader_decodeBinary(msg, pos, &p),; );
        UA_ResponseHeader_init(&r);
        r.requestHandle = p.requestHandle;
        r.serviceResult = UA_STATUSCODE_BADSERVICEUNSUPPORTED;
        UA_ByteString_newMembers(message, UA_ResponseHeader_calcSizeBinary(&r));
        UA_ResponseHeader_encodeBinary(&r, message, &sendOffset);
        UA_RequestHeader_deleteMembers(&p);
        UA_ResponseHeader_deleteMembers(&r);
        responseType = UA_RESPONSEHEADER_NS0 + 2;
        }
    	break;
    }

    // 5) Build the header
    UA_NodeId response_nodeid = { .namespaceIndex     = 0, .identifierType = UA_NODEIDTYPE_NUMERIC,
                                  .identifier.numeric = responseType }; // add 2 for binary encoding

    UA_ByteString_newMembers(header,
                             8 + 16 + // message header + 4*32bit secure channel information
                             UA_NodeId_calcSizeBinary(&response_nodeid));

    // header
    UA_TcpMessageHeader respHeader;
    respHeader.messageType = UA_MESSAGETYPE_MSG;
    respHeader.isFinal     = 'F';
    respHeader.messageSize = header->length + message->length;
    UA_UInt32 rpos = 0;
    UA_TcpMessageHeader_encodeBinary(&respHeader, header, &rpos);

    UA_UInt32_encodeBinary(&channel->securityToken.channelId, header, &rpos); // channel id
    UA_UInt32_encodeBinary(&channel->securityToken.tokenId, header, &rpos); // algorithm security header

    UA_UInt32_encodeBinary(&channel->sequenceNumber, header, &rpos); // encode sequence header
    UA_UInt32_encodeBinary(&channel->requestId, header, &rpos);

    UA_NodeId_encodeBinary(&response_nodeid, header, &rpos); // add payload type

    // sign data

    // encrypt data

    // 6) Send it over the wire.
    UA_ByteStringArray responseBufArray;
    responseBufArray.strings = responseBufs; // the content is deleted in the write function (asynchronous)
    responseBufArray.stringsSize = 2;
    connection->write(connection->callbackHandle, responseBufArray);
}

static void processClose(UA_Connection *connection, UA_Server *server, const UA_ByteString *msg, UA_UInt32 *pos) {
    // just read in the sequenceheader

    UA_UInt32 secureChannelId;
    UA_UInt32_decodeBinary(msg, pos, &secureChannelId);

	//the two last parameter is ignored since no answer is needed
	Service_CloseSecureChannel(server, secureChannelId);
}

void UA_Server_processBinaryMessage(UA_Server *server, UA_Connection *connection, const UA_ByteString *msg) {
    UA_Int32  retval = UA_STATUSCODE_GOOD;
    UA_UInt32 pos    = 0;
    UA_TcpMessageHeader tcpMessageHeader;
    // todo: test how far pos advanced must be equal to what is said in the messageheader
    do {
        retval = UA_TcpMessageHeader_decodeBinary(msg, &pos, &tcpMessageHeader);
        UA_UInt32 targetpos = pos - 8 + tcpMessageHeader.messageSize;
        if(retval == UA_STATUSCODE_GOOD) {
            // none of the process-functions returns an error its all contained inside.
            switch(tcpMessageHeader.messageType) {
            case UA_MESSAGETYPE_HEL:
                processHello(connection, msg, &pos);
                break;

            case UA_MESSAGETYPE_OPN:
                processOpen(connection, server, msg, &pos);
                break;

            case UA_MESSAGETYPE_MSG:
            	//no break
                // if this fails, the connection is closed (no break on the case)
                if(connection->state == UA_CONNECTION_ESTABLISHED &&
                   connection->channel != UA_NULL) {
                    processMessage(connection, server, msg, &pos);
                    break;
                }

            case UA_MESSAGETYPE_CLO:
                connection->state = UA_CONNECTION_CLOSING;
                processClose(connection, server, msg, &pos);
                connection->close(connection->callbackHandle);
                return;
            }
            UA_TcpMessageHeader_deleteMembers(&tcpMessageHeader);
        } else {
            printf("TL_Process - ERROR: decoding of header failed \n");
            connection->state = UA_CONNECTION_CLOSING;
            //processClose(connection, server, msg, &pos);
            connection->close(connection->callbackHandle);
        }
        // todo: more than one message at once..
        if(pos != targetpos) {
            printf("The message size was not as announced or an error occurred while processing, skipping to the end of the message.\n");
            pos = targetpos;
        }
    } while(msg->length > (UA_Int32)pos);
}