/* This work is licensed under a Creative Commons CCZero 1.0 Universal License.
 * See http://creativecommons.org/publicdomain/zero/1.0/ for more information.
 *
 * Copyright (c) 2021 Fraunhofer IOSB (Author: Jan Hermes)
 */

#include <open62541/plugin/log_stdout.h>
#include <open62541/server.h>
#include <open62541/server_pubsub.h>
#include <open62541/server_config_default.h>
#include <open62541/types_generated.h>

#include <open62541/plugin/securitypolicy_default.h>

#include <stdio.h>
#include <signal.h>
#include <stdlib.h>

#define UA_AES128CTR_SIGNING_KEY_LENGTH 32
#define UA_AES128CTR_KEY_LENGTH 16
#define UA_AES128CTR_KEYNONCE_LENGTH 4

UA_Byte signingKey[UA_AES128CTR_SIGNING_KEY_LENGTH] = {0};
UA_Byte encryptingKey[UA_AES128CTR_KEY_LENGTH] = {0};
UA_Byte keyNonce[UA_AES128CTR_KEYNONCE_LENGTH] = {0};

UA_NodeId connectionIdentifier;
UA_NodeId readerGroupIdentifier;
UA_NodeId readerIdentifier;

UA_DataSetReaderConfig readerConfig;

static void fillTestDataSetMetaData(UA_DataSetMetaDataType *pMetaData);

/* Add new connection to the server */
static UA_StatusCode
addPubSubConnection(UA_Server *server, UA_String *transportProfile,
                    UA_NetworkAddressUrlDataType *networkAddressUrl) {
    if((server == NULL) || (transportProfile == NULL) ||
        (networkAddressUrl == NULL)) {
        return UA_STATUSCODE_BADINTERNALERROR;
    }

    UA_StatusCode retval = UA_STATUSCODE_GOOD;
    /* Configuration creation for the connection */
    UA_PubSubConnectionConfig connectionConfig;
    memset (&connectionConfig, 0, sizeof(UA_PubSubConnectionConfig));
    connectionConfig.name = UA_STRING("UDPMC Connection 1");
    connectionConfig.transportProfileUri = *transportProfile;
    connectionConfig.enabled = UA_TRUE;
    UA_Variant_setScalar(&connectionConfig.address, networkAddressUrl,
                         &UA_TYPES[UA_TYPES_NETWORKADDRESSURLDATATYPE]);
    connectionConfig.publisherIdType = UA_PUBLISHERIDTYPE_UINT32;
    connectionConfig.publisherId.uint32 = UA_UInt32_random();
    retval |= UA_Server_addPubSubConnection (server, &connectionConfig, &connectionIdentifier);
    if (retval != UA_STATUSCODE_GOOD) {
        return retval;
    }

    return retval;
}

/**
 * **ReaderGroup**
 *
 * ReaderGroup is used to group a list of DataSetReaders. All ReaderGroups are
 * created within a PubSubConnection and automatically deleted if the connection
 * is removed. All network message related filters are only available in the DataSetReader. */
/* Add ReaderGroup to the created connection */
static UA_StatusCode
addReaderGroup(UA_Server *server) {
    if(server == NULL) {
        return UA_STATUSCODE_BADINTERNALERROR;
    }

    UA_StatusCode retval = UA_STATUSCODE_GOOD;
    UA_ReaderGroupConfig readerGroupConfig;
    memset (&readerGroupConfig, 0, sizeof(UA_ReaderGroupConfig));
    readerGroupConfig.name = UA_STRING("ReaderGroup1");

    /* Encryption settings */
    UA_ServerConfig *config = UA_Server_getConfig(server);
    readerGroupConfig.securityMode = UA_MESSAGESECURITYMODE_SIGNANDENCRYPT;
    readerGroupConfig.securityPolicy = &config->pubSubConfig.securityPolicies[0];

    retval |= UA_Server_addReaderGroup(server, connectionIdentifier, &readerGroupConfig,
                                       &readerGroupIdentifier);

    /* Add the encryption key informaton */
    UA_ByteString sk = {UA_AES128CTR_SIGNING_KEY_LENGTH, signingKey};
    UA_ByteString ek = {UA_AES128CTR_KEY_LENGTH, encryptingKey};
    UA_ByteString kn = {UA_AES128CTR_KEYNONCE_LENGTH, keyNonce};

    // TODO security token not necessary for readergroup (extracted from security-header)
    UA_Server_setReaderGroupEncryptionKeys(server, readerGroupIdentifier, 1, sk, ek, kn);

    // TODO setOperational MUST be after setting keys
    UA_Server_setReaderGroupOperational(server, readerGroupIdentifier);

    return retval;
}

/**
 * **DataSetReader**
 *
 * DataSetReader can receive NetworkMessages with the DataSetMessage
 * of interest sent by the Publisher. DataSetReader provides
 * the configuration necessary to receive and process DataSetMessages
 * on the Subscriber side. DataSetReader must be linked with a
 * SubscribedDataSet and be contained within a ReaderGroup. */
/* Add DataSetReader to the ReaderGroup */
static UA_StatusCode
addDataSetReader(UA_Server *server) {
    if(server == NULL) {
        return UA_STATUSCODE_BADINTERNALERROR;
    }

    UA_StatusCode retval = UA_STATUSCODE_GOOD;
    memset (&readerConfig, 0, sizeof(UA_DataSetReaderConfig));
    readerConfig.name = UA_STRING("DataSet Reader 1");
    /* Parameters to filter which DataSetMessage has to be processed
     * by the DataSetReader */
    /* The following parameters are used to show that the data published by
     * tutorial_pubsub_publish.c is being subscribed and is being updated in
     * the information model */
    UA_UInt16 publisherIdentifier = 2234;
    readerConfig.publisherId.type = &UA_TYPES[UA_TYPES_UINT16];
    readerConfig.publisherId.data = &publisherIdentifier;
    readerConfig.writerGroupId    = 100;
    readerConfig.dataSetWriterId  = 62541;

    /* Setting up Meta data configuration in DataSetReader */
    fillTestDataSetMetaData(&readerConfig.dataSetMetaData);

    retval |= UA_Server_addDataSetReader(server, readerGroupIdentifier, &readerConfig,
                                         &readerIdentifier);
    return retval;
}

/**
 * **SubscribedDataSet**
 *
 * Set SubscribedDataSet type to TargetVariables data type.
 * Add subscribedvariables to the DataSetReader */
static UA_StatusCode
addSubscribedVariables (UA_Server *server, UA_NodeId dataSetReaderId) {
    if(server == NULL)
        return UA_STATUSCODE_BADINTERNALERROR;

    UA_StatusCode retval = UA_STATUSCODE_GOOD;
    UA_NodeId folderId;
    UA_String folderName = readerConfig.dataSetMetaData.name;
    UA_ObjectAttributes oAttr = UA_ObjectAttributes_default;
    UA_QualifiedName folderBrowseName;
    if(folderName.length > 0) {
        oAttr.displayName.locale = UA_STRING ("en-US");
        oAttr.displayName.text = folderName;
        folderBrowseName.namespaceIndex = 1;
        folderBrowseName.name = folderName;
    }
    else {
        oAttr.displayName = UA_LOCALIZEDTEXT ("en-US", "Subscribed Variables");
        folderBrowseName = UA_QUALIFIEDNAME (1, "Subscribed Variables");
    }

    UA_Server_addObjectNode (server, UA_NODEID_NULL,
                             UA_NODEID_NUMERIC (0, UA_NS0ID_OBJECTSFOLDER),
                             UA_NODEID_NUMERIC (0, UA_NS0ID_ORGANIZES),
                             folderBrowseName, UA_NODEID_NUMERIC (0,
                             UA_NS0ID_BASEOBJECTTYPE), oAttr, NULL, &folderId);

/**
 * **TargetVariables**
 *
 * The SubscribedDataSet option TargetVariables defines a list of Variable mappings between
 * received DataSet fields and target Variables in the Subscriber AddressSpace.
 * The values subscribed from the Publisher are updated in the value field of these variables */
    /* Create the TargetVariables with respect to DataSetMetaData fields */
    UA_FieldTargetVariable *targetVars = (UA_FieldTargetVariable *)
            UA_calloc(readerConfig.dataSetMetaData.fieldsSize, sizeof(UA_FieldTargetVariable));
    for(size_t i = 0; i < readerConfig.dataSetMetaData.fieldsSize; i++) {
        /* Variable to subscribe data */
        UA_VariableAttributes vAttr = UA_VariableAttributes_default;
        UA_LocalizedText_copy(&readerConfig.dataSetMetaData.fields[i].description,
                              &vAttr.description);
        vAttr.displayName.locale = UA_STRING("en-US");
        vAttr.displayName.text = readerConfig.dataSetMetaData.fields[i].name;
        vAttr.dataType = readerConfig.dataSetMetaData.fields[i].dataType;

        UA_NodeId newNode;
        retval |= UA_Server_addVariableNode(server, UA_NODEID_NUMERIC(1, (UA_UInt32)i + 50000),
                                           folderId,
                                           UA_NODEID_NUMERIC(0, UA_NS0ID_HASCOMPONENT),
                                           UA_QUALIFIEDNAME(1, (char *)readerConfig.dataSetMetaData.fields[i].name.data),
                                           UA_NODEID_NUMERIC(0, UA_NS0ID_BASEDATAVARIABLETYPE),
                                           vAttr, NULL, &newNode);

        /* For creating Targetvariables */
        UA_FieldTargetDataType_init(&targetVars[i].targetVariable);
        targetVars[i].targetVariable.attributeId  = UA_ATTRIBUTEID_VALUE;
        targetVars[i].targetVariable.targetNodeId = newNode;
    }

    retval = UA_Server_DataSetReader_createTargetVariables(server, dataSetReaderId,
                                                           readerConfig.dataSetMetaData.fieldsSize, targetVars);
    for(size_t i = 0; i < readerConfig.dataSetMetaData.fieldsSize; i++)
        UA_FieldTargetDataType_clear(&targetVars[i].targetVariable);

    UA_free(targetVars);
    UA_free(readerConfig.dataSetMetaData.fields);
    return retval;
}

/**
 * **DataSetMetaData**
 *
 * The DataSetMetaData describes the content of a DataSet. It provides the information necessary to decode
 * DataSetMessages on the Subscriber side. DataSetMessages received from the Publisher are decoded into
 * DataSet and each field is updated in the Subscriber based on datatype match of TargetVariable fields of Subscriber
 * and PublishedDataSetFields of Publisher */
/* Define MetaData for TargetVariables */
static void fillTestDataSetMetaData(UA_DataSetMetaDataType *pMetaData) {
    if(pMetaData == NULL) {
        return;
    }

    UA_DataSetMetaDataType_init (pMetaData);
    pMetaData->name = UA_STRING ("DataSet 1");

    /* Static definition of number of fields size to 4 to create four different
     * targetVariables of distinct datatype
     * Currently the publisher sends only DateTime data type */
    pMetaData->fieldsSize = 4;
    pMetaData->fields = (UA_FieldMetaData*)UA_Array_new (pMetaData->fieldsSize,
                         &UA_TYPES[UA_TYPES_FIELDMETADATA]);

    /* DateTime DataType */
    UA_FieldMetaData_init (&pMetaData->fields[0]);
    UA_NodeId_copy (&UA_TYPES[UA_TYPES_DATETIME].typeId,
                    &pMetaData->fields[0].dataType);
    pMetaData->fields[0].builtInType = UA_NS0ID_DATETIME;
    pMetaData->fields[0].name =  UA_STRING ("DateTime");
    pMetaData->fields[0].valueRank = -1; /* scalar */

    /* Int32 DataType */
    UA_FieldMetaData_init (&pMetaData->fields[1]);
    UA_NodeId_copy(&UA_TYPES[UA_TYPES_INT32].typeId,
                   &pMetaData->fields[1].dataType);
    pMetaData->fields[1].builtInType = UA_NS0ID_INT32;
    pMetaData->fields[1].name =  UA_STRING ("Int32");
    pMetaData->fields[1].valueRank = -1; /* scalar */

    /* Int64 DataType */
    UA_FieldMetaData_init (&pMetaData->fields[2]);
    UA_NodeId_copy(&UA_TYPES[UA_TYPES_INT64].typeId,
                   &pMetaData->fields[2].dataType);
    pMetaData->fields[2].builtInType = UA_NS0ID_INT64;
    pMetaData->fields[2].name =  UA_STRING ("Int64");
    pMetaData->fields[2].valueRank = -1; /* scalar */

    /* Boolean DataType */
    UA_FieldMetaData_init (&pMetaData->fields[3]);
    UA_NodeId_copy (&UA_TYPES[UA_TYPES_BOOLEAN].typeId,
                    &pMetaData->fields[3].dataType);
    pMetaData->fields[3].builtInType = UA_NS0ID_BOOLEAN;
    pMetaData->fields[3].name =  UA_STRING ("BoolToggle");
    pMetaData->fields[3].valueRank = -1; /* scalar */
}

/*
 * TODO: add something similary ass addDataSetMetadata for security configuration
 */

/**
 * Followed by the main server code, making use of the above definitions */
UA_Boolean running = true;
static void stopHandler(int sign) {
    UA_LOG_INFO(UA_Log_Stdout, UA_LOGCATEGORY_SERVER, "received ctrl-c");
    running = false;
}

static int
run(UA_String *transportProfile, UA_NetworkAddressUrlDataType *networkAddressUrl) {
    signal(SIGINT, stopHandler);
    signal(SIGTERM, stopHandler);
    /* Return value initialized to Status Good */
    UA_StatusCode retval = UA_STATUSCODE_GOOD;
    UA_Server *server = UA_Server_new();
    UA_ServerConfig *config = UA_Server_getConfig(server);
    UA_ServerConfig_setMinimal(config, 4801, NULL);

    /* Instantiate the PubSub SecurityPolicy */
    config->pubSubConfig.securityPolicies = (UA_PubSubSecurityPolicy*)
        UA_malloc(sizeof(UA_PubSubSecurityPolicy));
    config->pubSubConfig.securityPoliciesSize = 1;
    UA_PubSubSecurityPolicy_Aes128Ctr(config->pubSubConfig.securityPolicies,
                                      config->logging);

    /* API calls */
    /* Add PubSubConnection */
    retval |= addPubSubConnection(server, transportProfile, networkAddressUrl);
    if (retval != UA_STATUSCODE_GOOD)
        return EXIT_FAILURE;

    /* Add ReaderGroup to the created PubSubConnection */
    retval |= addReaderGroup(server);
    if (retval != UA_STATUSCODE_GOOD)
        return EXIT_FAILURE;

    /* Add DataSetReader to the created ReaderGroup */
    retval |= addDataSetReader(server);
    if (retval != UA_STATUSCODE_GOOD)
        return EXIT_FAILURE;

    /* Add SubscribedVariables to the created DataSetReader */
    retval |= addSubscribedVariables(server, readerIdentifier);
    if (retval != UA_STATUSCODE_GOOD)
        return EXIT_FAILURE;

    retval = UA_Server_run(server, &running);
    UA_Server_delete(server);
    return retval == UA_STATUSCODE_GOOD ? EXIT_SUCCESS : EXIT_FAILURE;
}

static void
usage(char *progname) {
    printf("usage: %s <uri> [device]\n", progname);
}

int main(int argc, char **argv) {
    UA_String transportProfile =
        UA_STRING("http://opcfoundation.org/UA-Profile/Transport/pubsub-udp-uadp");
    UA_NetworkAddressUrlDataType networkAddressUrl =
        {UA_STRING_NULL , UA_STRING("opc.udp://224.0.0.22:4840/")};

    if (argc > 1) {
        if (strcmp(argv[1], "-h") == 0) {
            usage(argv[0]);
            return EXIT_SUCCESS;
        }

        if (strncmp(argv[1], "opc.udp://", 10) == 0) {
            networkAddressUrl.url = UA_STRING(argv[1]);
        } else if (strncmp(argv[1], "opc.eth://", 10) == 0) {
            transportProfile =
                UA_STRING("http://opcfoundation.org/UA-Profile/Transport/pubsub-eth-uadp");
            if (argc < 3) {
                printf("Error: UADP/ETH needs an interface name\n");
                return EXIT_FAILURE;
            }
            networkAddressUrl.networkInterface = UA_STRING(argv[2]);
            networkAddressUrl.url = UA_STRING(argv[1]);
        } else {
            printf("Error: unknown URI\n");
            return EXIT_FAILURE;
        }
    }

    return run(&transportProfile, &networkAddressUrl);
}