// Copyright 2015-2016 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 "openssl_client.h"

#include <string.h>

#include "openssl/ssl.h"

#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/event_groups.h"

#include "esp_log.h"
#include "esp_wifi.h"
#include "esp_event_loop.h"

#include "nvs_flash.h"

#include "lwip/sockets.h"
#include "lwip/netdb.h"

static EventGroupHandle_t wifi_event_group;

/* The event group allows multiple bits for each event,
   but we only care about one event - are we connected
   to the AP with an IP? */
const static int CONNECTED_BIT = BIT0;

const static char *TAG = "Openssl_demo";

void openssl_demo_thread(void *p)
{
    int ret;
    SSL_CTX *ctx;
    SSL *ssl;
    int socket;
    struct sockaddr_in sock_addr;
    struct hostent *hp;
    struct ip4_addr *ip4_addr;
    
    int recv_bytes = 0;
    char recv_buf[OPENSSL_DEMO_RECV_BUF_LEN];
    
    const char send_data[] = OPENSSL_DEMO_REQUEST;
    const int send_bytes = sizeof(send_data);

    ESP_LOGI(TAG, "OpenSSL demo thread start OK");

    ESP_LOGI(TAG, "get target IP address");
    hp = gethostbyname(OPENSSL_DEMO_TARGET_NAME);
    if (!hp) {
        ESP_LOGI(TAG, "failed");
        goto failed1;
    }
    ESP_LOGI(TAG, "OK");

    ip4_addr = (struct ip4_addr *)hp->h_addr;
    ESP_LOGI(TAG, IPSTR, IP2STR(ip4_addr));

    ESP_LOGI(TAG, "create SSL context ......");
    ctx = SSL_CTX_new(TLSv1_1_client_method());
    if (!ctx) {
        ESP_LOGI(TAG, "failed");
        goto failed1;
    }
    ESP_LOGI(TAG, "OK");

    ESP_LOGI(TAG, "create socket ......");
    socket = socket(AF_INET, SOCK_STREAM, 0);
    if (socket < 0) {
        ESP_LOGI(TAG, "failed");
        goto failed2;
    }
    ESP_LOGI(TAG, "OK");

    ESP_LOGI(TAG, "bind socket ......");
    memset(&sock_addr, 0, sizeof(sock_addr));
    sock_addr.sin_family = AF_INET;
    sock_addr.sin_addr.s_addr = 0;
    sock_addr.sin_port = htons(OPENSSL_DEMO_LOCAL_TCP_PORT);
    ret = bind(socket, (struct sockaddr*)&sock_addr, sizeof(sock_addr));
    if (ret) {
        ESP_LOGI(TAG, "failed");
        goto failed3;
    }
    ESP_LOGI(TAG, "OK");

    ESP_LOGI(TAG, "socket connect to remote %s ......", OPENSSL_DEMO_TARGET_NAME);
    memset(&sock_addr, 0, sizeof(sock_addr));
    sock_addr.sin_family = AF_INET;
    sock_addr.sin_addr.s_addr = ip4_addr->addr;
    sock_addr.sin_port = htons(OPENSSL_DEMO_TARGET_TCP_PORT);
    ret = connect(socket, (struct sockaddr*)&sock_addr, sizeof(sock_addr));
    if (ret) {
        ESP_LOGI(TAG, "failed");
        goto failed3;
    }
    ESP_LOGI(TAG, "OK");

    ESP_LOGI(TAG, "create SSL ......");
    ssl = SSL_new(ctx);
    if (!ssl) {
        ESP_LOGI(TAG, "failed");
        goto failed3;
    }
    ESP_LOGI(TAG, "OK");

    SSL_set_fd(ssl, socket);

    ESP_LOGI(TAG, "SSL connected to %s port %d ......",
        OPENSSL_DEMO_TARGET_NAME, OPENSSL_DEMO_TARGET_TCP_PORT);
    ret = SSL_connect(ssl);
    if (!ret) {
        ESP_LOGI(TAG, "failed " );
        goto failed4;
    }
    ESP_LOGI(TAG, "OK");

    ESP_LOGI(TAG, "send https request to %s port %d ......",
        OPENSSL_DEMO_TARGET_NAME, OPENSSL_DEMO_TARGET_TCP_PORT);
    ret = SSL_write(ssl, send_data, send_bytes);
    if (ret <= 0) {
        ESP_LOGI(TAG, "failed");
        goto failed5;
    }
    ESP_LOGI(TAG, "OK");

    do {
        ret = SSL_read(ssl, recv_buf, OPENSSL_DEMO_RECV_BUF_LEN - 1);
        if (ret <= 0) {
            break;
        }
        recv_bytes += ret;
        ESP_LOGI(TAG, "%s", recv_buf);
    } while (1);
    
    ESP_LOGI(TAG, "totaly read %d bytes data from %s ......", recv_bytes, OPENSSL_DEMO_TARGET_NAME);

failed5:
    SSL_shutdown(ssl);
failed4:
    SSL_free(ssl);
    ssl = NULL;
failed3:
    close(socket);
    socket = -1;
failed2:
    SSL_CTX_free(ctx);
    ctx = NULL;
failed1:
    vTaskDelete(NULL);
    return ;
}

static void openssl_client_init(void)
{
    int ret;
    xTaskHandle openssl_handle;

    ret = xTaskCreate(openssl_demo_thread,
                      OPENSSL_DEMO_THREAD_NAME,
                      OPENSSL_DEMO_THREAD_STACK_WORDS,
                      NULL,
                      OPENSSL_DEMO_THREAD_PRORIOTY,
                      &openssl_handle); 

    if (ret != pdPASS)  {
        ESP_LOGI(TAG, "create thread %s failed", OPENSSL_DEMO_THREAD_NAME);
    }
}

static esp_err_t wifi_event_handler(void *ctx, system_event_t *event)
{
    switch(event->event_id) {
    case SYSTEM_EVENT_STA_START:
        esp_wifi_connect();
        break;
    case SYSTEM_EVENT_STA_GOT_IP:
        xEventGroupSetBits(wifi_event_group, CONNECTED_BIT);
        openssl_client_init();
        break;
    case SYSTEM_EVENT_STA_DISCONNECTED:
        /* This is a workaround as ESP32 WiFi libs don't currently
           auto-reassociate. */
        esp_wifi_connect(); 
        xEventGroupClearBits(wifi_event_group, CONNECTED_BIT);
        break;
    default:
        break;
    }
    return ESP_OK;
}

static void wifi_conn_init(void)
{
    tcpip_adapter_init();
    wifi_event_group = xEventGroupCreate();
    ESP_ERROR_CHECK( esp_event_loop_init(wifi_event_handler, NULL) );
    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK( esp_wifi_init(&cfg) );
    ESP_ERROR_CHECK( esp_wifi_set_storage(WIFI_STORAGE_RAM) );
    wifi_config_t wifi_config = {
        .sta = {
            .ssid = EXAMPLE_WIFI_SSID,
            .password = EXAMPLE_WIFI_PASS,
        },
    };
    ESP_ERROR_CHECK( esp_wifi_set_mode(WIFI_MODE_STA) );
    ESP_ERROR_CHECK( esp_wifi_set_config(WIFI_IF_STA, &wifi_config) );
    ESP_LOGI(TAG, "start the WIFI SSID:[%s] password:[%s]\n", EXAMPLE_WIFI_SSID, EXAMPLE_WIFI_PASS);
    ESP_ERROR_CHECK( esp_wifi_start() );
}

void app_main(void)
{
    nvs_flash_init();
    wifi_conn_init();
}