#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;
                }
                LOG_INFO("");
                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();
}
}
}