#include <AP_HAL/AP_HAL_Boards.h>

#if AP_DDS_ENABLED

#include <AP_GPS/AP_GPS.h>
#include <AP_RTC/AP_RTC.h>
#include <AP_SerialManager/AP_SerialManager.h>
#include <GCS_MAVLink/GCS.h>

#include "AP_DDS_Client.h"
#include "generated/Time.h"

static constexpr uint16_t DELAY_TIME_TOPIC_MS = 10;
static constexpr uint16_t DELAY_NAV_SAT_FIX_TOPIC_MS = 1000;
static char WGS_84_FRAME_ID[] = "WGS-84";

AP_HAL::UARTDriver *dds_port;


const AP_Param::GroupInfo AP_DDS_Client::var_info[]= {
    //! @todo Params go here

    AP_GROUPEND
};

#include "AP_DDS_Topic_Table.h"

void AP_DDS_Client::update_topic(builtin_interfaces_msg_Time& msg)
{
    uint64_t utc_usec;
    if (!AP::rtc().get_utc_usec(utc_usec)) {
        utc_usec = AP_HAL::micros64();
    }
    msg.sec = utc_usec / 1000000ULL;
    msg.nanosec = (utc_usec % 1000000ULL) * 1000UL;

}

void AP_DDS_Client::update_topic(sensor_msgs_msg_NavSatFix& msg, const uint8_t instance)
{
    // Add a lambda that takes in navsatfix msg and populates the cov
    // Make it constexpr if possible
    // https://www.fluentcpp.com/2021/12/13/the-evolutions-of-lambdas-in-c14-c17-and-c20/
    // constexpr auto times2 = [] (sensor_msgs_msg_NavSatFix* msg) { return n * 2; };

    // assert(instance >= GPS_MAX_RECEIVERS);
    if (instance >= GPS_MAX_RECEIVERS) {
        return;
    }

    update_topic(msg.header.stamp);
    strcpy(msg.header.frame_id, WGS_84_FRAME_ID);
    msg.status.service = 0; // SERVICE_GPS
    msg.status.status = -1; // STATUS_NO_FIX

    auto &gps = AP::gps();
    WITH_SEMAPHORE(gps.get_semaphore());

    if (!gps.is_healthy(instance)) {
        msg.status.status = -1; // STATUS_NO_FIX
        msg.status.service = 0; // No services supported
        msg.position_covariance_type = 0; // COVARIANCE_TYPE_UNKNOWN
        return;
    }


    //! @todo What about glonass, compass, galileo?
    //! This will be properly designed and implemented to spec in #23277
    msg.status.service = 1; // SERVICE_GPS

    const auto status = gps.status(instance);
    switch (status) {
    case AP_GPS::NO_GPS:
    case AP_GPS::NO_FIX:
        msg.status.status = -1; // STATUS_NO_FIX
        msg.position_covariance_type = 0; // COVARIANCE_TYPE_UNKNOWN
        return;
    case AP_GPS::GPS_OK_FIX_2D:
    case AP_GPS::GPS_OK_FIX_3D:
        msg.status.status = 0; // STATUS_FIX
        msg.position_covariance_type = 1; // COVARIANCE_TYPE_APPROXIMATED
        break;
    case AP_GPS::GPS_OK_FIX_3D_DGPS:
        msg.status.status = 1; // STATUS_SBAS_FIX
        msg.position_covariance_type = 1; // COVARIANCE_TYPE_APPROXIMATED
        break;
    case AP_GPS::GPS_OK_FIX_3D_RTK_FLOAT:
    case AP_GPS::GPS_OK_FIX_3D_RTK_FIXED:
        msg.status.status = 2; // STATUS_SBAS_FIX
        msg.position_covariance_type = 1; // COVARIANCE_TYPE_APPROXIMATED
        // RTK provides "rtk_accuracy" member, should it be used for the covariance?
        break;
    default:
        //! @todo Can we not just use an enum class and not worry about this condition?
        break;
    }
    const auto loc = gps.location(instance);
    msg.latitude = loc.lat * 1E-7;
    msg.longitude = loc.lng * 1E-7;

    int32_t alt_cm;
    if (!loc.get_alt_cm(Location::AltFrame::ABSOLUTE, alt_cm)) {
        // With absolute frame, this condition is unlikely
        msg.status.status = -1; // STATUS_NO_FIX
        msg.position_covariance_type = 0; // COVARIANCE_TYPE_UNKNOWN
        return;
    }
    msg.altitude = alt_cm / 100.0;

    // Calculate covariance: https://answers.ros.org/question/10310/calculate-navsatfix-covariance/
    // https://github.com/ros-drivers/nmea_navsat_driver/blob/indigo-devel/src/libnmea_navsat_driver/driver.py#L110-L114
    //! @todo This calculation will be moved to AP::gps and fixed in #23259
    //! It is a placeholder for now matching the ROS1 nmea_navsat_driver behavior
    const auto hdop = gps.get_hdop(instance);
    const auto hdopSq = hdop * hdop;
    const auto vdop = gps.get_vdop(instance);
    const auto vdopSq = vdop * vdop;
    msg.position_covariance[0] = hdopSq;
    msg.position_covariance[4] = hdopSq;
    msg.position_covariance[8] = vdopSq;
}


/*
  class constructor
 */
AP_DDS_Client::AP_DDS_Client(void)
{
    if (!hal.scheduler->thread_create(FUNCTOR_BIND_MEMBER(&AP_DDS_Client::main_loop, void),
                                      "DDS",
                                      8192, AP_HAL::Scheduler::PRIORITY_IO, 1)) {
        GCS_SEND_TEXT(MAV_SEVERITY_ERROR,"DDS Client: thread create failed");
    }
}

/*
  main loop for DDS thread
 */
void AP_DDS_Client::main_loop(void)
{
    if (!init() || !create()) {
        GCS_SEND_TEXT(MAV_SEVERITY_ERROR,"DDS Client: Creation Requests failed");
        return;
    }
    GCS_SEND_TEXT(MAV_SEVERITY_INFO,"DDS Client: Initialization passed");
    while (true) {
        hal.scheduler->delay(1);
        update();
    }
}


bool AP_DDS_Client::init()
{
    AP_SerialManager *serial_manager = AP_SerialManager::get_singleton();
    dds_port = serial_manager->find_serial(AP_SerialManager::SerialProtocol_DDS_XRCE, 0);
    if (dds_port == nullptr) {
        return false;
    }

    // ensure we own the UART
    dds_port->begin(0);

    constexpr uint8_t fd = 0;
    constexpr uint8_t relativeSerialAgentAddr = 0;
    constexpr uint8_t relativeSerialClientAddr = 1;
    if (!uxr_init_serial_transport(&serial_transport,fd,relativeSerialAgentAddr,relativeSerialClientAddr)) {
        return false;
    }

    constexpr uint32_t uniqueClientKey = 0xAAAABBBB;
    //TODO does this need to be inside the loop to handle reconnect?
    uxr_init_session(&session, &serial_transport.comm, uniqueClientKey);
    while (!uxr_create_session(&session)) {
        GCS_SEND_TEXT(MAV_SEVERITY_INFO,"DDS Client: Initialization waiting...");
        hal.scheduler->delay(1000);
    }

    reliable_in = uxr_create_input_reliable_stream(&session,input_reliable_stream,BUFFER_SIZE_SERIAL,STREAM_HISTORY);
    reliable_out = uxr_create_output_reliable_stream(&session,output_reliable_stream,BUFFER_SIZE_SERIAL,STREAM_HISTORY);

    GCS_SEND_TEXT(MAV_SEVERITY_INFO,"DDS Client: Init Complete");

    return true;
}

bool AP_DDS_Client::create()
{
    WITH_SEMAPHORE(csem);

    // Participant
    const uxrObjectId participant_id = {
        .id = 0x01,
        .type = UXR_PARTICIPANT_ID
    };
    const char* participant_ref = "participant_profile";
    const auto participant_req_id = uxr_buffer_create_participant_ref(&session, reliable_out, participant_id,0,participant_ref,UXR_REPLACE);

    //Participant requests
    constexpr uint8_t nRequestsParticipant = 1;
    const uint16_t requestsParticipant[nRequestsParticipant] = {participant_req_id};

    constexpr int maxTimeMsPerRequestMs = 250;
    constexpr int requestTimeoutParticipantMs = nRequestsParticipant * maxTimeMsPerRequestMs;
    uint8_t statusParticipant[nRequestsParticipant];
    if (!uxr_run_session_until_all_status(&session, requestTimeoutParticipantMs, requestsParticipant, statusParticipant, nRequestsParticipant)) {
        GCS_SEND_TEXT(MAV_SEVERITY_ERROR,"XRCE Client: Participant session request failure");
        // TODO add a failure log message sharing the status results
        return false;
    }

    for (size_t i = 0 ; i < ARRAY_SIZE(topics); i++) {
        // Topic
        const uxrObjectId topic_id = {
            .id = topics[i].topic_id,
            .type = UXR_TOPIC_ID
        };
        const char* topic_ref = topics[i].topic_profile_label;
        const auto topic_req_id = uxr_buffer_create_topic_ref(&session,reliable_out,topic_id,participant_id,topic_ref,UXR_REPLACE);

        // Publisher
        const uxrObjectId pub_id = {
            .id = topics[i].pub_id,
            .type = UXR_PUBLISHER_ID
        };
        const char* pub_xml = "";
        const auto pub_req_id = uxr_buffer_create_publisher_xml(&session,reliable_out,pub_id,participant_id,pub_xml,UXR_REPLACE);

        // Data Writer
        const char* data_writer_ref = topics[i].dw_profile_label;
        const auto dwriter_req_id = uxr_buffer_create_datawriter_ref(&session,reliable_out,topics[i].dw_id,pub_id,data_writer_ref,UXR_REPLACE);

        // Status requests
        constexpr uint8_t nRequests = 3;
        const uint16_t requests[nRequests] = {topic_req_id, pub_req_id, dwriter_req_id};
        constexpr int requestTimeoutMs = nRequests * maxTimeMsPerRequestMs;
        uint8_t status[nRequests];
        if (!uxr_run_session_until_all_status(&session, requestTimeoutMs, requests, status, nRequests)) {
            GCS_SEND_TEXT(MAV_SEVERITY_ERROR,"XRCE Client: Topic/Pub/Writer session request failure for index 'TODO'");
            for (int s = 0 ; s < nRequests; s++) {
                GCS_SEND_TEXT(MAV_SEVERITY_ERROR,"XRCE Client: Status '%d' result '%u'", s, status[s]);
            }
            // TODO add a failure log message sharing the status results
            return false;
        } else {
            GCS_SEND_TEXT(MAV_SEVERITY_INFO,"XRCE Client: Topic/Pub/Writer session pass for index 'TOOO'");
        }
    }

    return true;
}

void AP_DDS_Client::write_time_topic()
{
    WITH_SEMAPHORE(csem);
    if (connected) {
        ucdrBuffer ub;
        const uint32_t topic_size = builtin_interfaces_msg_Time_size_of_topic(&time_topic, 0);
        uxr_prepare_output_stream(&session,reliable_out,topics[0].dw_id,&ub,topic_size);
        const bool success = builtin_interfaces_msg_Time_serialize_topic(&ub, &time_topic);
        if (!success) {
            // TODO sometimes serialization fails on bootup. Determine why.
            // AP_HAL::panic("FATAL: XRCE_Client failed to serialize\n");
        }
    }
}

void AP_DDS_Client::write_nav_sat_fix_topic()
{
    WITH_SEMAPHORE(csem);
    if (connected) {
        ucdrBuffer ub;
        const uint32_t topic_size = sensor_msgs_msg_NavSatFix_size_of_topic(&nav_sat_fix_topic, 0);
        uxr_prepare_output_stream(&session,reliable_out,topics[1].dw_id,&ub,topic_size);
        const bool success = sensor_msgs_msg_NavSatFix_serialize_topic(&ub, &nav_sat_fix_topic);
        if (!success) {
            // TODO sometimes serialization fails on bootup. Determine why.
            // AP_HAL::panic("FATAL: DDS_Client failed to serialize\n");
        }
    }
}

void AP_DDS_Client::update()
{
    WITH_SEMAPHORE(csem);

    const auto cur_time_ms = AP_HAL::millis64();

    if (cur_time_ms - last_time_time_ms > DELAY_TIME_TOPIC_MS) {
        update_topic(time_topic);
        last_time_time_ms = cur_time_ms;
        write_time_topic();
    }

    if (cur_time_ms - last_nav_sat_fix_time_ms > DELAY_NAV_SAT_FIX_TOPIC_MS) {
        constexpr uint8_t instance = 0;
        update_topic(nav_sat_fix_topic, instance);
        last_nav_sat_fix_time_ms = cur_time_ms;
        write_nav_sat_fix_topic();
    }

    connected = uxr_run_session_time(&session, 1);
}

/*
  implement C functions for serial transport
 */
extern "C" {
#include <uxr/client/profile/transport/serial/serial_transport_platform.h>
}

bool uxr_init_serial_platform(void* args, int fd, uint8_t remote_addr, uint8_t local_addr)
{
    //! @todo Add error reporting
    return true;
}

bool uxr_close_serial_platform(void* args)
{
    //! @todo Add error reporting
    return true;
}

size_t uxr_write_serial_data_platform(void* args, const uint8_t* buf, size_t len, uint8_t* errcode)
{
    if (dds_port == nullptr) {
        *errcode = 1;
        return 0;
    }
    ssize_t bytes_written = dds_port->write(buf, len);
    if (bytes_written <= 0) {
        *errcode = 1;
        return 0;
    }
    //! @todo Add populate the error code correctly
    *errcode = 0;
    return bytes_written;
}

size_t uxr_read_serial_data_platform(void* args, uint8_t* buf, size_t len, int timeout, uint8_t* errcode)
{
    if (dds_port == nullptr) {
        *errcode = 1;
        return 0;
    }
    while (timeout > 0 && dds_port->available() < len) {
        hal.scheduler->delay(1); // TODO select or poll this is limiting speed (1mS)
        timeout--;
    }
    ssize_t bytes_read = dds_port->read(buf, len);
    if (bytes_read <= 0) {
        *errcode = 1;
        return 0;
    }
    //! @todo Add error reporting
    *errcode = 0;
    return bytes_read;
}

#if CONFIG_HAL_BOARD != HAL_BOARD_SITL
extern "C" {
    int clock_gettime(clockid_t clockid, struct timespec *ts);
}

int clock_gettime(clockid_t clockid, struct timespec *ts)
{
    //! @todo the value of clockid is ignored here.
    //! A fallback mechanism is employed against the caller's choice of clock.
    uint64_t utc_usec;
    if (!AP::rtc().get_utc_usec(utc_usec)) {
        utc_usec = AP_HAL::micros64();
    }
    ts->tv_sec = utc_usec / 1000000ULL;
    ts->tv_nsec = (utc_usec % 1000000ULL) * 1000UL;
    return 0;
}
#endif // CONFIG_HAL_BOARD

#endif // AP_DDS_ENABLED