#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/event_groups.h"
#include "esp_system.h"
#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#include "nvs_flash.h"
#include <esp_http_server.h>

#define WIFI_SSID "AndroidAP"
#define WIFI_PASS "uyts6533"


// Event group
static EventGroupHandle_t wifi_event_group;
const int CONNECTED_BIT = BIT0;

static char* resp_str ="\
		<input type=\"submit\" name=\"lamp_state\" onclick=\"sendState(this.value)\" value=\"ON\"> \
		<input type=\"submit\" name=\"lamp_state\" onclick=\"sendState(this.value)\" value=\"OFF\"> \
		<label class=\"switch\">\
			<input type=\"checkbox\">\
			<span class=\"slider\"></span>\
		</label>\
		</form> \
		\
		<input type=\"range\" min=\"0\" max=\"100\" value=\"0\" oninput=\"sendSlider(this.value)\" class=\"slider\" id=\"myRange\"> \
		<script> \
		function sendSlider(data) { \
			const XHR = new XMLHttpRequest(); \
			XHR.open('POST', '/hello'); \
			XHR.send(\"brightness=\"+data); \
		} \
		function sendState(data) { \
			const XHR = new XMLHttpRequest(); \
			XHR.open('POST', '/hello'); \
			XHR.send(\"lamp_state=\"+data); \
		} \
		</script> \
		";

static esp_err_t default_get_handler(httpd_req_t *req)
{
    httpd_resp_send(req, resp_str, strlen(resp_str));
    return ESP_OK;
}

static const httpd_uri_t default_uri = {
    .uri       = "/",
    .method    = HTTP_GET,
    .handler   = &default_get_handler
};

// Wifi event handler
static esp_err_t 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);
        break;
    
	case SYSTEM_EVENT_STA_DISCONNECTED:
		xEventGroupClearBits(wifi_event_group, CONNECTED_BIT);
        printf("disconnected!\n");
        break;
    
	default:
        break;
    }
   
	return ESP_OK;
}

// Main application
void app_main()
{
	// disable the default wifi logging
	esp_log_level_set("wifi", ESP_LOG_NONE);
	
	// initialize NVS
	ESP_ERROR_CHECK(nvs_flash_init());
	
	// create the event group to handle wifi events
	wifi_event_group = xEventGroupCreate();
		
	// initialize the tcp stack
	tcpip_adapter_init();

	// initialize the wifi event handler
	ESP_ERROR_CHECK(esp_event_loop_init(event_handler, NULL));
	
	// initialize the wifi stack in STAtion mode with config in RAM
	wifi_init_config_t wifi_init_config = WIFI_INIT_CONFIG_DEFAULT();
	ESP_ERROR_CHECK(esp_wifi_init(&wifi_init_config));
	ESP_ERROR_CHECK(esp_wifi_set_storage(WIFI_STORAGE_RAM));
	ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));

	// configure the wifi connection and start the interface
	wifi_config_t wifi_config = {
        .sta = {
            .ssid = WIFI_SSID,
            .password = WIFI_PASS,
        },
    };
	ESP_ERROR_CHECK(esp_wifi_set_config(ESP_IF_WIFI_STA, &wifi_config));
    ESP_ERROR_CHECK(esp_wifi_start());
	printf("Connecting to %s\n", WIFI_SSID);
	
    EventBits_t uxBits;
	uxBits = xEventGroupWaitBits(wifi_event_group, CONNECTED_BIT, false, true, 5000 / portTICK_PERIOD_MS);
    if( ( uxBits & CONNECTED_BIT ) != 0 )
    {
        printf("Connected!\n");
    }
    else{
        printf("Not connected!\n");
        ESP_ERROR_CHECK(esp_wifi_stop());

        esp_wifi_set_mode(WIFI_MODE_AP);
        wifi_config_t ap_config = {
            .ap = {
                .ssid = "lamp",
                .channel = 0,
                .authmode = WIFI_AUTH_OPEN,
                .ssid_hidden = 0,
                .max_connection = 1,
                .beacon_interval = 100
            }
        };
        esp_wifi_set_config(WIFI_IF_AP, &ap_config);
        ESP_ERROR_CHECK(esp_wifi_start());
    }
    httpd_handle_t server = NULL;
    httpd_config_t config = HTTPD_DEFAULT_CONFIG();

    // Start the httpd server
    printf("Starting server on port: '%d'", config.server_port);
    if (httpd_start(&server, &config) == ESP_OK) {
        // Set URI handlers
        httpd_register_uri_handler(server, &default_uri);
    }
}