/*
 * Copyright (C) 2018 Freie Universität Berlin
 *               2018 Codecoup
 *
 * This file is subject to the terms and conditions of the GNU Lesser
 * General Public License v2.1. See the file LICENSE in the top level
 * directory for more details.
 */

/**
 * @ingroup     examples
 * @{
 *
 * @file
 * @brief       BLE peripheral example using NimBLE
 *
 * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
 * @author      Andrzej Kaczmarek <andrzej.kaczmarek@codecoup.pl>
 *
 * @}
 */

#include <stdio.h>
#include <string.h>

#include "nimble_riot.h"

#include "nimble/nimble_port.h"
#include "host/ble_hs.h"
#include "host/util/util.h"
#include "services/gap/ble_svc_gap.h"
#include "services/gatt/ble_svc_gatt.h"

static const char device_name[] = "NimBLE on RIOT";
static uint8_t own_addr_type;


static void start_advertise(void);

static void put_ad(uint8_t ad_type, uint8_t ad_len, const void *ad, uint8_t *buf,
                   uint8_t *len)
{
    buf[(*len)++] = ad_len + 1;
    buf[(*len)++] = ad_type;

    memcpy(&buf[*len], ad, ad_len);

    *len += ad_len;
}

static void update_ad(void)
{
    uint8_t ad[BLE_HS_ADV_MAX_SZ];
    uint8_t ad_len = 0;
    uint8_t ad_flags = BLE_HS_ADV_F_DISC_GEN | BLE_HS_ADV_F_BREDR_UNSUP;

    put_ad(BLE_HS_ADV_TYPE_FLAGS, 1, &ad_flags, ad, &ad_len);
    put_ad(BLE_HS_ADV_TYPE_COMP_NAME, sizeof(device_name), device_name, ad, &ad_len);

    ble_gap_adv_set_data(ad, ad_len);
}

static int gap_event_cb(struct ble_gap_event *event, void *arg)
{
    (void)arg;

    switch (event->type) {
        case BLE_GAP_EVENT_CONNECT:
            if (event->connect.status) {
                start_advertise();
            }
            break;

        case BLE_GAP_EVENT_DISCONNECT:
            start_advertise();
            break;
    }

    return 0;
}

static void start_advertise(void)
{
    struct ble_gap_adv_params advp;
    int rc;

    memset(&advp, 0, sizeof advp);
    advp.conn_mode = BLE_GAP_CONN_MODE_UND;
    advp.disc_mode = BLE_GAP_DISC_MODE_GEN;
    rc = ble_gap_adv_start(own_addr_type, NULL, BLE_HS_FOREVER,
                           &advp, gap_event_cb, NULL);
    assert(rc == 0);
}

static void app_ble_sync_cb(void)
{
    int rc;

    rc = ble_hs_util_ensure_addr(0);
    assert(rc == 0);

    rc = ble_hs_id_infer_auto(0, &own_addr_type);
    assert(rc == 0);

    /* generate the advertising data */
    update_ad();

    start_advertise();
}

int main(void)
{
    puts("NimBLE GATT Server Example");

    /* initialize NimBLE's controller */
    nimble_riot_controller_init();

    /* register the synchronization callback that is triggered once the host has
     * finished its initialization */
    ble_hs_cfg.sync_cb = app_ble_sync_cb;

    /* initialize NimBLE porting layer and the default GATT and GAP services*/
    nimble_port_init();
    ble_svc_gap_init();
    ble_svc_gatt_init();

    /* set the device name */
    ble_svc_gap_device_name_set(device_name);

    /* and finally run NimBLE's host event loop. The event loop contains a pre-
     * configured event which will trigger the hosts initialization */
    nimble_port_run();

    return 0;
}