#include "esp_wifi.h"
#include "esp_event.h"
#include "esp_log.h"
#include "esp_system.h"
#include "esp_spiffs.h"
#include <esp_http_server.h>
#include <nvs_flash.h>

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

#include "driver/gpio.h"
#include "driver/ledc.h"

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

#include <sys/param.h>

#include "esp_netif.h"
#include "esp_eth.h"


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

#define ESP_INTR_FLAG_DEFAULT 0

uint8_t led_state = 1;
volatile uint16_t led_duty = 6075;
void connect_to_wifi(char* new_ssid, char* new_psk);

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

ledc_timer_config_t ledc_timer = {
    .duty_resolution = LEDC_TIMER_13_BIT, // resolution of PWM duty
    .freq_hz = 5000,                      // frequency of PWM signal
    .speed_mode = LEDC_LOW_SPEED_MODE,           // timer mode
    .timer_num = LEDC_TIMER_1,            // timer index
    .clk_cfg = LEDC_AUTO_CLK,              // Auto select the source clock
};
ledc_channel_config_t ledc_channel =
{
    .channel    = LEDC_CHANNEL_0,
    .duty       = 0,
    .gpio_num   = 5,
    .speed_mode = LEDC_LOW_SPEED_MODE,
    .hpoint     = 0,
    .timer_sel  = LEDC_TIMER_1
};

static char* website_lamp_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\"> \
		<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', '/lamp_ctrl'); \
			XHR.send(\"brightness=\"+data); \
		} \
		function sendState(data) { \
			const XHR = new XMLHttpRequest(); \
			XHR.open('POST', '/lamp_ctrl'); \
			XHR.send(\"lamp_state=\"+data); \
		} \
		</script> \
		";

static char* website_wifi_str ="<form action=\"wifi\" method=\"post\">\n<table>\n<tr>\n<td>SSID:</td>\n<td><input type=\"text\" name=\"SSID\"></td>\n</tr>\n<tr>\n<td>PSK :</td>\n<td><input type=\"text\" name=\"PSK\"></td>\n</tr>\n</table>\n<input type=\"submit\" value=\"Submit\">\n</form>";

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

static esp_err_t web_wifi_get_handler(httpd_req_t *req)
{
    httpd_resp_send(req, website_wifi_str, strlen(website_wifi_str));
    return ESP_OK;
}

static esp_err_t web_wifi_post_handler(httpd_req_t *req)
{
    char buf[256];
    int ret, remaining = req->content_len;

    char ssid[32];
    char psk[64];

    while (remaining > 0) {
        /* Read the data for the request */
        if ((ret = httpd_req_recv(req, buf, MIN(remaining, sizeof(buf)))) <= 0) {
            if (ret == HTTPD_SOCK_ERR_TIMEOUT) {
                /* Retry receiving if timeout occurred */
                continue;
            }
            return ESP_FAIL;
        }
        remaining -= ret;

        /* NULL terminal string */
        buf[ret] = 0;


        char *string, *found;
        string = strdup(buf);
        while( (found = strsep(&string,"&")) != NULL ){
            if(strncmp(found, "SSID=", 5)==0){
                memcpy(ssid,&found[5],strlen(&found[5])+1);
            }
            if(strncmp(found, "PSK=", 4)==0){
                memcpy(psk,&found[4],strlen(&found[4])+1);
            }
        }
    }
    connect_to_wifi(ssid, psk);

    httpd_resp_send(req, website_wifi_str, strlen(website_wifi_str));
    return ESP_OK;
}

static esp_err_t lamp_ctrl_post_handler(httpd_req_t *req)
{
    char buf[100];
    int ret, remaining = req->content_len;

    while (remaining > 0) {
        /* Read the data for the request */
        if ((ret = httpd_req_recv(req, buf, MIN(remaining, sizeof(buf)))) <= 0) {
            if (ret == HTTPD_SOCK_ERR_TIMEOUT) {
                /* Retry receiving if timeout occurred */
                continue;
            }
            return ESP_FAIL;
        }
        remaining -= ret;

        if(strncmp(buf, "lamp_state=ON", 13)==0){
            led_state=1;
        }
        if(strncmp(buf, "lamp_state=OFF", 14)==0){
            led_state=0;
        }
        if(strncmp(buf, "brightness=", 11)==0){
            int bright = atoi(&buf[11]);
            printf("bright=%d\n", bright);
            int duty = ((1<<13)-1)/100*bright;
            printf("duty=%d\n\n", duty);
            led_duty = duty;
        }
    }
    httpd_resp_send(req, NULL, 0);
    return ESP_OK;
}


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

static const httpd_uri_t web_wifi_uri = {
    .uri       = "/wifi",
    .method    = HTTP_GET,
    .handler   = &web_wifi_get_handler
};

static const httpd_uri_t web_wifi_post_uri = {
    .uri       = "/wifi",
    .method    = HTTP_POST,
    .handler   = &web_wifi_post_handler
};

static const httpd_uri_t lamp_ctrl_post_uri = {
    .uri       = "/lamp_ctrl",
    .method    = HTTP_POST,
    .handler   = &lamp_ctrl_post_handler
};

static void IRAM_ATTR gpio_isr_handler(void* arg)
{
    uint32_t gpio_num = (uint32_t) arg;
    xQueueSendFromISR(gpio_evt_queue, &gpio_num, NULL);
}

static void button_debounce_task(void* arg){
    static uint8_t debounce_active;

    if(!debounce_active){
        debounce_active = 1;
        printf("debounce active\n");
        vTaskDelay(50 / portTICK_RATE_MS);
        if(gpio_get_level(17)==0){
            led_state^=1;
            printf("setting state = %d\n",led_state);
        }
        debounce_active = 0;
    }
    vTaskDelete( NULL );
}

static void led_task(void* arg)
{
    printf("started led task!");
    for(;;){
        if(led_state){
            ledc_set_duty(ledc_channel.speed_mode, ledc_channel.channel, led_duty);
            ledc_update_duty(ledc_channel.speed_mode, ledc_channel.channel);
        }
        else{
            ledc_set_duty(ledc_channel.speed_mode, ledc_channel.channel, 0);
            ledc_update_duty(ledc_channel.speed_mode, ledc_channel.channel);
        }
        vTaskDelay(10 / portTICK_RATE_MS);
    }
}

static void gpio_task(void* arg)
{
    printf("GPIO task started\n");
    uint32_t io_num;
    for(;;) {
        if(xQueueReceive(gpio_evt_queue, &io_num, portMAX_DELAY)) {
            xTaskCreate(&button_debounce_task, "button_debounce_task", 2048, NULL, 10, NULL);
        }
    }
}

void connect_to_wifi(char* new_ssid, char* new_psk){
    printf("ssid: \'%s\'\n", new_ssid);
    printf("psk:\'%s\'\n", new_psk);

    ESP_ERROR_CHECK(esp_wifi_stop());

    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 = {*new_ssid},
            .password = {*new_psk}
        }
    };
    strcpy(&(wifi_config.sta.ssid), new_ssid);
    strcpy(&(wifi_config.sta.password), new_psk);

    printf("ssid: \'%s\'\n", wifi_config.sta.ssid);
    printf("psk: \'%s\'\n", wifi_config.sta.password);

	ESP_ERROR_CHECK(esp_wifi_set_config(ESP_IF_WIFI_STA, &wifi_config));
    ESP_ERROR_CHECK(esp_wifi_start());
}

// 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()
{
    ledc_timer_config(&ledc_timer);
    ledc_channel_config(&ledc_channel);


    xTaskCreate(&led_task, "led_task", 2048, NULL, 5, NULL);

    gpio_config_t io_conf;
    io_conf.intr_type = GPIO_PIN_INTR_NEGEDGE;
    io_conf.pin_bit_mask = (1ULL<<17);
    io_conf.mode = GPIO_MODE_INPUT;
    io_conf.pull_down_en = 0;
    io_conf.pull_up_en = 1;
    gpio_config(&io_conf);

    gpio_evt_queue = xQueueCreate(10, sizeof(uint32_t));
    xTaskCreate(&gpio_task, "gpio_task", 2048, NULL, 10, NULL);
    gpio_install_isr_service(ESP_INTR_FLAG_DEFAULT);
    gpio_isr_handler_add(17, gpio_isr_handler, (void*) 17);

    //esp_vfs_spiffs_conf_t spiffs_conf = {
    //  .base_path = "/spiffs",
    //  .partition_label = NULL,
    //  .max_files = 5,
    //  .format_if_mount_failed = true
    //};
    //esp_err_t ret = esp_vfs_spiffs_register(&spiffs_conf);

    //static const char *TAG = "example";
    //if (ret != ESP_OK) {
    //    if (ret == ESP_FAIL) {
    //        ESP_LOGE(TAG, "Failed to mount or format filesystem");
    //    } else if (ret == ESP_ERR_NOT_FOUND) {
    //        ESP_LOGE(TAG, "Failed to find SPIFFS partition");
    //    } else {
    //        ESP_LOGE(TAG, "Failed to initialize SPIFFS (%d)", ret);
    //    }
    //    return;
    //}

    //size_t total = 0, used = 0;
    //ret = esp_spiffs_info(NULL, &total, &used);
    //if (ret != ESP_OK) {
    //            ESP_LOGE(TAG, "Failed to get SPIFFS partition information");
    //                
    //}

    //ESP_LOGI(TAG, "Reading file");
    //FILE* f = fopen("/spiffs/index.html", "r");
    //if (f == NULL) {
    //    ESP_LOGE(TAG, "Failed to open file for reading");
    //    return;
    //}
    //char line[64];
    //fgets(line, sizeof(line), f);
    //fclose(f);
    //// strip newline
    //char* pos = strchr(line, '\n');
    //if (pos) {
    //    *pos = '\0';
    //}
    //ESP_LOGI(TAG, "Read from file: '%s'", line);

    //// All done, unmount partition and disable SPIFFS
    //esp_vfs_spiffs_unregister(NULL);
    //ESP_LOGI(TAG, "SPIFFS unmounted");

	// 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);
        httpd_register_uri_handler(server, &web_wifi_uri);
        httpd_register_uri_handler(server, &web_wifi_post_uri);
        httpd_register_uri_handler(server, &lamp_ctrl_post_uri);
    }
}