#include <Bluetooth/Device.hpp>
#include <log/log.hpp>
#include <vector>
#include <Bluetooth/Error.hpp>

extern "C"
{
#include "btstack.h"
};

btstack_packet_callback_registration_t cb_handler;
enum DEVICE_STATE
{
    REMOTE_NAME_REQUEST,
    REMOTE_NAME_INQUIRED,
    REMOTE_NAME_FETCHED
};

struct Devicei : public Device
{
  public:
    bd_addr_t address;
    uint8_t pageScanRepetitionMode;
    uint16_t clockOffset;
    enum DEVICE_STATE state;

    Devicei(std::string name = "") : name(name)
    {}
    virtual ~Devicei()
    {}
    void address_set(bd_addr_t *addr)
    {
        memcpy(&address, addr, sizeof address);
    }
    std::string name;
};

std::vector<Devicei> devices;

static int getDeviceIndexForAddress(std::vector<Devicei> &devs, bd_addr_t addr)
{
    int j;
    for (j = 0; j < devs.size(); j++) {
        if (bd_addr_cmp(addr, devs[j].address) == 0) {
            return j;
        }
    }
    return -1;
}

enum STATE
{
    INIT,
    ACTIVE,
    DONE
};
enum STATE state = INIT;

#define INQUIRY_INTERVAL 5
static int start_scan(void)
{
    LOG_INFO("Starting inquiry scan..");
    return gap_inquiry_start(INQUIRY_INTERVAL);
}

static int has_more_remote_name_requests(void)
{
    int i;
    for (i = 0; i < devices.size(); i++) {
        if (devices[i].state == REMOTE_NAME_REQUEST)
            return 1;
    }
    return 0;
}

static void do_next_remote_name_request(void)
{
    int i;
    for (i = 0; i < devices.size(); i++) {
        // remote name request
        if (devices[i].state == REMOTE_NAME_REQUEST) {
            devices[i].state = REMOTE_NAME_INQUIRED;
            LOG_INFO("Get remote name of %s...", bd_addr_to_str(devices[i].address));
            gap_remote_name_request(
                devices[i].address, devices[i].pageScanRepetitionMode, devices[i].clockOffset | 0x8000);
            return;
        }
    }
}

static void continue_remote_names(void)
{
    if (has_more_remote_name_requests()) {
        do_next_remote_name_request();
        return;
    }
    start_scan();
}

static void packet_handler(uint8_t packet_type, uint16_t channel, uint8_t *packet, uint16_t size)
{
    UNUSED(channel);
    UNUSED(size);

    bd_addr_t addr;
    int i;
    int index;

    if (packet_type != HCI_EVENT_PACKET)
        return;

    uint8_t event = hci_event_packet_get_type(packet);

    switch (state) {
    /* @text In INIT, an inquiry  scan is started, and the application transits to
     * ACTIVE state.
     */
    case INIT:
        switch (event) {
        case BTSTACK_EVENT_STATE:
            if (btstack_event_state_get_state(packet) == HCI_STATE_WORKING) {
                state = ACTIVE;
            }
            break;
        default:
            break;
        }
        break;

    /* @text In ACTIVE, the following events are processed:
     *  - GAP Inquiry result event: BTstack provides a unified inquiry result that contain
     *    Class of Device (CoD), page scan mode, clock offset. RSSI and name (from EIR) are optional.
     *  - Inquiry complete event: the remote name is requested for devices without a fetched
     *    name. The state of a remote name can be one of the following:
     *    REMOTE_NAME_REQUEST, REMOTE_NAME_INQUIRED, or REMOTE_NAME_FETCHED.
     *  - Remote name request complete event: the remote name is stored in the table and the
     *    state is updated to REMOTE_NAME_FETCHED. The query of remote names is continued.
     */
    case ACTIVE:
        switch (event) {

        case GAP_EVENT_INQUIRY_RESULT: {
            gap_event_inquiry_result_get_bd_addr(packet, addr);
            index = getDeviceIndexForAddress(devices, addr);
            if (index >= 0)
                break; // already in our list

            Devicei dev;
            dev.address_set(&addr);
            dev.pageScanRepetitionMode = gap_event_inquiry_result_get_page_scan_repetition_mode(packet);
            dev.clockOffset            = gap_event_inquiry_result_get_clock_offset(packet);
            // print info
            LOG_INFO("Device found: %s ", bd_addr_to_str(addr));
            LOG_INFO("with COD: 0x%06x, ", (unsigned int)gap_event_inquiry_result_get_class_of_device(packet));
            LOG_INFO("pageScan %d, ", dev.pageScanRepetitionMode);
            LOG_INFO("clock offset 0x%04x", dev.clockOffset);
            if (gap_event_inquiry_result_get_rssi_available(packet)) {
                LOG_INFO(", rssi %d dBm", (int8_t)gap_event_inquiry_result_get_rssi(packet));
            }
            if (gap_event_inquiry_result_get_name_available(packet)) {
                char name_buffer[240];
                int name_len = gap_event_inquiry_result_get_name_len(packet);
                memcpy(name_buffer, gap_event_inquiry_result_get_name(packet), name_len);
                name_buffer[name_len] = 0;
                LOG_INFO(", name '%s'", name_buffer);
                dev.state = REMOTE_NAME_FETCHED;
                ;
            }
            else {
                dev.state = REMOTE_NAME_REQUEST;
            }
            devices.push_back(dev);
        } break;

        case GAP_EVENT_INQUIRY_COMPLETE:
            for (i = 0; i < devices.size(); i++) {
                // retry remote name request
                if (devices[i].state == REMOTE_NAME_INQUIRED)
                    devices[i].state = REMOTE_NAME_REQUEST;
            }
            continue_remote_names();
            break;

        case HCI_EVENT_REMOTE_NAME_REQUEST_COMPLETE: {
            reverse_bd_addr(&packet[3], addr);
            index = getDeviceIndexForAddress(devices, addr);
            if (index >= 0) {
                if (packet[2] == 0) {
                    LOG_INFO("Name: '%s'", &packet[9]);
                    devices[index].state = REMOTE_NAME_FETCHED;
                    devices[index].name  = reinterpret_cast<char *>(&packet[9]);
                }
                else {
                    LOG_INFO("Failed to get name: page timeout");
                }
            }
            if (index + 1 == devices.size()) {
                LOG_INFO("Scanned all");
                state = DONE;
            }
            continue_remote_names();
        } break;

        default:
            break;
        }
        break;

    default:
        break;
    }
}

namespace Bt
{
    namespace GAP
    {

        Error register_scan()
        {
            LOG_INFO("GAP register scan!");
            /// -> this have to be called prior to power on!
            hci_set_inquiry_mode(INQUIRY_MODE_RSSI_AND_EIR);
            cb_handler.callback = &packet_handler;
            hci_add_event_handler(&cb_handler);
            return Error();
        }

        Error scan()
        {
            // TODO We dont use results now, we dont store/return them
            LOG_INFO("Start scan if active: %d: %d", hci_get_state(), state);
            if (hci_get_state() == HCI_STATE_WORKING) {
                if (int ret = start_scan() != 0) {
                    LOG_ERROR("Start scan error!: 0x%X", ret);
                    return Error(Error::LibraryError, ret);
                }
            }
            else {
                return Error(Error::NotReady);
            }
            return Error();
        }
    } // namespace GAP
} // namespace Bt