// Copyright 2015-2017 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <stdint.h>
#include <string.h>
#include <stdbool.h>
#include <stdio.h>
#include "nvs.h"
#include "nvs_flash.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"
#include "esp_bt.h"
#include "esp_bt_main.h"
#include "esp_gap_bt_api.h"
#include "esp_bt_device.h"
#include "esp_spp_api.h"

#include "time.h"
#include "sys/time.h"

#define SPP_TAG "SPP_INITIATOR_DEMO"
#define EXCAMPLE_DEVICE_NAME "ESP_SPP_INITIATOR"

#define SPP_SHOW_DATA 0
#define SPP_SHOW_SPEED 1
#define SPP_SHOW_MODE SPP_SHOW_SPEED    /*Choose show mode: show data or speed*/

static const esp_spp_mode_t esp_spp_mode = ESP_SPP_MODE_CB;

static struct timeval time_new, time_old;
static long data_num = 0;

static const esp_spp_sec_t sec_mask = ESP_SPP_SEC_NONE;
static const esp_spp_role_t role_master = ESP_SPP_ROLE_MASTER;

static esp_bd_addr_t peer_bd_addr;
static uint8_t peer_bdname_len;
static char peer_bdname[ESP_BT_GAP_MAX_BDNAME_LEN + 1];
static const char remote_device_name[] = "ESP_SPP_ACCEPTOR";
static const esp_bt_inq_mode_t inq_mode = ESP_BT_INQ_MODE_GENERAL_INQUIRY;
static const uint8_t inq_len = 30;
static const uint8_t inq_num_rsps = 0;

#if (SPP_SHOW_MODE == SPP_SHOW_DATA)
#define SPP_DATA_LEN 20
#else
#define SPP_DATA_LEN ESP_SPP_MAX_MTU
#endif
static uint8_t spp_data[SPP_DATA_LEN];

static void print_speed(void)
{
    float time_old_s = time_old.tv_sec + time_old.tv_usec / 1000000.0;
    float time_new_s = time_new.tv_sec + time_new.tv_usec / 1000000.0;
    float time_interval = time_new_s - time_old_s;
    float speed = data_num * 8 / time_interval / 1000.0;
    ESP_LOGI(SPP_TAG, "speed(%fs ~ %fs): %f kbit/s" , time_old_s, time_new_s, speed);
    data_num = 0;
    time_old.tv_sec = time_new.tv_sec;
    time_old.tv_usec = time_new.tv_usec;
}

static bool get_name_from_eir(uint8_t *eir, char *bdname, uint8_t *bdname_len)
{
    uint8_t *rmt_bdname = NULL;
    uint8_t rmt_bdname_len = 0;

    if (!eir) {
        return false;
    }

    rmt_bdname = esp_bt_gap_resolve_eir_data(eir, ESP_BT_EIR_TYPE_CMPL_LOCAL_NAME, &rmt_bdname_len);
    if (!rmt_bdname) {
        rmt_bdname = esp_bt_gap_resolve_eir_data(eir, ESP_BT_EIR_TYPE_SHORT_LOCAL_NAME, &rmt_bdname_len);
    }

    if (rmt_bdname) {
        if (rmt_bdname_len > ESP_BT_GAP_MAX_BDNAME_LEN) {
            rmt_bdname_len = ESP_BT_GAP_MAX_BDNAME_LEN;
        }

        if (bdname) {
            memcpy(bdname, rmt_bdname, rmt_bdname_len);
            bdname[rmt_bdname_len] = '\0';
        }
        if (bdname_len) {
            *bdname_len = rmt_bdname_len;
        }
        return true;
    }

    return false;
}

static void esp_spp_cb(esp_spp_cb_event_t event, esp_spp_cb_param_t *param)
{
    switch (event) {
    case ESP_SPP_INIT_EVT:
        ESP_LOGI(SPP_TAG, "ESP_SPP_INIT_EVT");
        esp_bt_dev_set_device_name(EXCAMPLE_DEVICE_NAME);
        esp_bt_gap_set_scan_mode(ESP_BT_SCAN_MODE_CONNECTABLE_DISCOVERABLE);
        esp_bt_gap_start_discovery(inq_mode, inq_len, inq_num_rsps);

        break;
    case ESP_SPP_DISCOVERY_COMP_EVT:
        ESP_LOGI(SPP_TAG, "ESP_SPP_DISCOVERY_COMP_EVT status=%d scn_num=%d",param->disc_comp.status, param->disc_comp.scn_num);
        if (param->disc_comp.status == ESP_SPP_SUCCESS) {
            esp_spp_connect(sec_mask, role_master, param->disc_comp.scn[0], peer_bd_addr);
        }
        break;
    case ESP_SPP_OPEN_EVT:
        ESP_LOGI(SPP_TAG, "ESP_SPP_OPEN_EVT");
        esp_spp_write(param->srv_open.handle, SPP_DATA_LEN, spp_data);
        gettimeofday(&time_old, NULL);
        break;
    case ESP_SPP_CLOSE_EVT:
        ESP_LOGI(SPP_TAG, "ESP_SPP_CLOSE_EVT");
        break;
    case ESP_SPP_START_EVT:
        ESP_LOGI(SPP_TAG, "ESP_SPP_START_EVT");
        break;
    case ESP_SPP_CL_INIT_EVT:
        ESP_LOGI(SPP_TAG, "ESP_SPP_CL_INIT_EVT");
        break;
    case ESP_SPP_DATA_IND_EVT:
        ESP_LOGI(SPP_TAG, "ESP_SPP_DATA_IND_EVT");
        break;
    case ESP_SPP_CONG_EVT:
#if (SPP_SHOW_MODE == SPP_SHOW_DATA)
        ESP_LOGI(SPP_TAG, "ESP_SPP_CONG_EVT cong=%d", param->cong.cong);
#endif
        if (param->cong.cong == 0) {
            esp_spp_write(param->cong.handle, SPP_DATA_LEN, spp_data);
        }
        break;
    case ESP_SPP_WRITE_EVT:
#if (SPP_SHOW_MODE == SPP_SHOW_DATA)
        ESP_LOGI(SPP_TAG, "ESP_SPP_WRITE_EVT len=%d cong=%d", param->write.len , param->write.cong);
        esp_log_buffer_hex("",spp_data,SPP_DATA_LEN);
#else
        gettimeofday(&time_new, NULL);
        data_num += param->write.len;
        if (time_new.tv_sec - time_old.tv_sec >= 3) {
            print_speed();
        }
#endif
        if (param->write.cong == 0) {
            esp_spp_write(param->write.handle, SPP_DATA_LEN, spp_data);
        }
        break;
    case ESP_SPP_SRV_OPEN_EVT:
        ESP_LOGI(SPP_TAG, "ESP_SPP_SRV_OPEN_EVT");
        break;
    default:
        break;
    }
}

static void esp_bt_gap_cb(esp_bt_gap_cb_event_t event, esp_bt_gap_cb_param_t *param)
{
    switch(event){
        case ESP_BT_GAP_DISC_RES_EVT:
            ESP_LOGI(SPP_TAG, "ESP_BT_GAP_DISC_RES_EVT");
            esp_log_buffer_hex(SPP_TAG, param->disc_res.bda, ESP_BD_ADDR_LEN);
            for (int i = 0; i < param->disc_res.num_prop; i++){
                if (param->disc_res.prop[i].type == ESP_BT_GAP_DEV_PROP_EIR
                    && get_name_from_eir(param->disc_res.prop[i].val, peer_bdname, &peer_bdname_len)){
                    esp_log_buffer_char(SPP_TAG, peer_bdname, peer_bdname_len);
                    if (strlen(remote_device_name) == peer_bdname_len
                        && strncmp(peer_bdname, remote_device_name, peer_bdname_len) == 0) {
                        memcpy(peer_bd_addr, param->disc_res.bda, ESP_BD_ADDR_LEN);
                        esp_spp_start_discovery(peer_bd_addr);
                        esp_bt_gap_cancel_discovery();
                    }
                }
            }
            break;
        case ESP_BT_GAP_DISC_STATE_CHANGED_EVT:
            ESP_LOGI(SPP_TAG, "ESP_BT_GAP_DISC_STATE_CHANGED_EVT");
            break;
        case ESP_BT_GAP_RMT_SRVCS_EVT:
            ESP_LOGI(SPP_TAG, "ESP_BT_GAP_RMT_SRVCS_EVT");
            break;
        case ESP_BT_GAP_RMT_SRVC_REC_EVT:
            ESP_LOGI(SPP_TAG, "ESP_BT_GAP_RMT_SRVC_REC_EVT");
            break;
        default:
            break;
    }
}

void app_main()
{
    for (int i = 0; i < SPP_DATA_LEN; ++i) {
        spp_data[i] = i;
    }

    esp_err_t ret = nvs_flash_init();
    if (ret == ESP_ERR_NVS_NO_FREE_PAGES) {
        ESP_ERROR_CHECK(nvs_flash_erase());
        ret = nvs_flash_init();
    }
    ESP_ERROR_CHECK( ret );


    esp_bt_controller_config_t bt_cfg = BT_CONTROLLER_INIT_CONFIG_DEFAULT();
    if (esp_bt_controller_init(&bt_cfg) != ESP_OK) {
        ESP_LOGE(SPP_TAG, "%s initialize controller failed\n", __func__);
        return;
    }

    if (esp_bt_controller_enable(ESP_BT_MODE_CLASSIC_BT) != ESP_OK) {
        ESP_LOGE(SPP_TAG, "%s enable controller failed\n", __func__);
        return;
    }

    if (esp_bluedroid_init() != ESP_OK) {
        ESP_LOGE(SPP_TAG, "%s initialize bluedroid failed\n", __func__);
        return;
    }

    if (esp_bluedroid_enable() != ESP_OK) {
        ESP_LOGE(SPP_TAG, "%s enable bluedroid failed\n", __func__);
        return;
    }

    if (esp_bt_gap_register_callback(esp_bt_gap_cb) != ESP_OK) {
        ESP_LOGE(SPP_TAG, "%s gap register failed\n", __func__);
        return;
    }

    if (esp_spp_register_callback(esp_spp_cb) != ESP_OK) {
        ESP_LOGE(SPP_TAG, "%s spp register failed\n", __func__);
        return;
    }

    if (esp_spp_init(esp_spp_mode) != ESP_OK) {
        ESP_LOGE(SPP_TAG, "%s spp init failed\n", __func__);
        return;
    }
}