#include <stdint.h>
#include <string.h>
#include <stdio.h>
#include <stdatomic.h>
#include <freertos/FreeRTOS.h>
#include <freertos/task.h>
#include <freertos/event_groups.h>
#include <freertos/projdefs.h>
#include <esp_system.h>
#include <esp_wifi.h>
#include <driver/gpio.h>
#include <esp_event.h>
#include <esp_log.h>
#include <nvs_flash.h>
#include <lwip/err.h>
#include <lwip/sys.h>
#include <cJSON.h>
#include "esp_http_server.h"
#include "esp_adc/adc_oneshot.h"
#include "esp_adc/adc_cali.h"
#include "esp_adc/adc_cali_scheme.h"
#include "esp_task_wdt.h"

#include "sdkconfig.h"
#include "frontend.h"

#define AP_MAX_CONN         4
#define AP_CHANNEL          6

#define ADC_CHAN0          ADC_CHANNEL_4
#define ADC_CHAN1          ADC_CHANNEL_5
#define ADC_ATTEN_DB       ADC_ATTEN_DB_12

#define THRESHOLD_UP_NVS_NAME "threshold_up"
#define THRESHOLD_LOW_NVS_NAME "threshold_low"
#define NVS_PARTITION "nvs"

#define SENSOR_ADC_CHAN 0
#define MAX_JSON_CONTENT 512

#define FILTER_SAMPLES 5

#define PRIORITY_HTTP     1
#define PRIORITY_CONTROL  2
#define PRIORITY_SENSOR   3

static adc_oneshot_unit_handle_t adc_handle;
static adc_cali_handle_t cali_handle;
static bool is_calibrated = false;

static atomic_int g_threshold_low = 0;
static atomic_int g_threshold_up = 0;
static atomic_int g_current_pressure = 0;

static const char TAG[] = "Pump Controller";

static esp_err_t parse_thresholds_json(const char *content, int *low_value, int *up_value) {
    cJSON *json = cJSON_Parse(content);
    if (!json) {
        return ESP_FAIL;
    }

    cJSON *low_item = cJSON_GetObjectItem(json, "low");
    cJSON *up_item = cJSON_GetObjectItem(json, "up");

    bool valid = cJSON_IsNumber(low_item) && cJSON_IsNumber(up_item);
    if (valid) {
        *low_value = low_item->valueint;
        *up_value = up_item->valueint;
    }

    cJSON_Delete(json);
    return valid ? ESP_OK : ESP_FAIL;
}

static esp_err_t receive_http_content(httpd_req_t *req, char **content) {
    size_t content_len = req->content_len;

    if (content_len > MAX_JSON_CONTENT) {
        httpd_resp_send_err(req, HTTPD_400_BAD_REQUEST, "Content too large");
        return ESP_FAIL;
    }

    *content = malloc(content_len + 1);
    if (!*content) {
        httpd_resp_send_err(req, HTTPD_500_INTERNAL_SERVER_ERROR, "Memory allocation failed");
        return ESP_FAIL;
    }

    int ret = httpd_req_recv(req, *content, content_len);
    if (ret <= 0) {
        free(*content);
        httpd_resp_send_err(req, HTTPD_400_BAD_REQUEST, "Failed to receive data");
        return ESP_FAIL;
    }
    (*content)[content_len] = '\0';

    return ESP_OK;
}

static esp_err_t send_json_response(httpd_req_t *req, const char *format, ...) {
    char response[100];
    va_list args;
    va_start(args, format);
    vsnprintf(response, sizeof(response), format, args);
    va_end(args);

    httpd_resp_set_type(req, "application/json");
    httpd_resp_send(req, response, strlen(response));
    return ESP_OK;
}

esp_err_t adc_init(void) {
    adc_oneshot_unit_init_cfg_t init_config = {
        .unit_id = ADC_UNIT_1,
    };
    esp_err_t ret = adc_oneshot_new_unit(&init_config, &adc_handle);
    if (ret != ESP_OK) return ret;

    adc_oneshot_chan_cfg_t config = {
        .atten = ADC_ATTEN_DB,
        .bitwidth = ADC_BITWIDTH_DEFAULT,
    };
    ret = adc_oneshot_config_channel(adc_handle, ADC_CHAN0, &config);
    if (ret != ESP_OK) return ret;

    ret = adc_oneshot_config_channel(adc_handle, ADC_CHAN1, &config);
    if (ret != ESP_OK) return ret;

    adc_cali_line_fitting_config_t cali_config = {
        .unit_id = ADC_UNIT_1,
        .atten = ADC_ATTEN_DB,
        .bitwidth = ADC_BITWIDTH_DEFAULT,
    };

    ret = adc_cali_create_scheme_line_fitting(&cali_config, &cali_handle);
    if (ret == ESP_OK) {
        is_calibrated = true;
        ESP_LOGI(TAG, "ADC success calibration");
    } else if (ret == ESP_ERR_NOT_SUPPORTED) {
        ESP_LOGW(TAG, "Calibrating not available (eFuse doesn't written)");
    } else {
        ESP_LOGE(TAG, "Error calibrating");
    }

    return ESP_OK;
}

static void pump_init(void) {
    gpio_config_t io_conf = {
        .pin_bit_mask = (1ULL << CONFIG_PUMP_PIN),
        .mode = GPIO_MODE_OUTPUT,
        .intr_type = GPIO_INTR_DISABLE,
        .pull_down_en = 1,
        .pull_up_en = 0,
    };
    gpio_config(&io_conf);
    gpio_set_level(CONFIG_PUMP_PIN, false);
}

int adc_read_raw(uint8_t channel)
{
    int raw_value = 0;
    adc_channel_t adc_channel;

    if (channel == 0) {
        adc_channel = ADC_CHAN0;
    } else if (channel == 1) {
        adc_channel = ADC_CHAN1;
    } else {
        ESP_LOGE(TAG, "Wrong ADC channel: %d", channel);
        return -1;
    }

    esp_err_t ret = adc_oneshot_read(adc_handle, adc_channel, &raw_value);
    if (ret != ESP_OK) {
        ESP_LOGE(TAG, "Error reading ADC");
        return -1;
    }
    return raw_value;
}

int adc_read_voltage(uint8_t channel) {
    int raw_value = adc_read_raw(channel);
    if (raw_value < 0) return -1;

    if (is_calibrated) {
        int voltage_mv = 0;
        esp_err_t ret = adc_cali_raw_to_voltage(cali_handle, raw_value, &voltage_mv);
        if (ret != ESP_OK) {
            ESP_LOGE(TAG, "Error convert to voltage");
            return -1;
        }
        return voltage_mv;
    } else {
        return (raw_value * 3300) / 4095;
    }
}

static esp_err_t root_get_handler(httpd_req_t *req) {
    httpd_resp_set_type(req, "text/html; charset=utf-8");
    httpd_resp_send(req, (const char*)assets_index_html, HTTPD_RESP_USE_STRLEN);
    return ESP_OK;
}

static esp_err_t current_pressure_handler(httpd_req_t *req) {
    int sensor_value = atomic_load(&g_current_pressure);
    return send_json_response(req, "{\"value\":%d}", sensor_value);
}

static esp_err_t save_thresholds_handler(httpd_req_t *req) {
    char *content = NULL;
    if (receive_http_content(req, &content) != ESP_OK) {
        return ESP_FAIL;
    }

    int low_value = 0, up_value = 0;
    if (parse_thresholds_json(content, &low_value, &up_value) != ESP_OK) {
        free(content);
        httpd_resp_send_err(req, HTTPD_400_BAD_REQUEST, "Missing or invalid 'low' or 'up' parameters");
        return ESP_FAIL;
    }
    free(content);

    if (low_value >= up_value) {
        httpd_resp_send_err(req, HTTPD_400_BAD_REQUEST, "Low value must be less than up value");
        return ESP_FAIL;
    }

    nvs_handle_t my_handle;
    esp_err_t err = nvs_open(NVS_PARTITION, NVS_READWRITE, &my_handle);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "Error opening NVS");
        return ESP_FAIL;
    }

    err = nvs_set_i32(my_handle, THRESHOLD_LOW_NVS_NAME, low_value);
    if (err != ESP_OK) {
        nvs_close(my_handle);
        httpd_resp_send_err(req, HTTPD_500_INTERNAL_SERVER_ERROR, "Failed to save");
        return ESP_FAIL;
    }

    err = nvs_set_i32(my_handle, THRESHOLD_UP_NVS_NAME, up_value);
    if (err != ESP_OK) {
        nvs_close(my_handle);
        httpd_resp_send_err(req, HTTPD_500_INTERNAL_SERVER_ERROR, "Failed to save");
        return ESP_FAIL;
    }

    err = nvs_commit(my_handle);
    ESP_ERROR_CHECK(err);
    nvs_close(my_handle);

    return send_json_response(req, "{\"success\":true,\"low\":%d,\"up\":%d}", low_value, up_value);
}

static esp_err_t set_thresholds_handler(httpd_req_t *req) {
    char *content = NULL;
    if (receive_http_content(req, &content) != ESP_OK) {
        return ESP_FAIL;
    }

    int low_value = 0, up_value = 0;
    if (parse_thresholds_json(content, &low_value, &up_value) != ESP_OK) {
        free(content);
        httpd_resp_send_err(req, HTTPD_400_BAD_REQUEST, "Missing or invalid 'low' or 'up' parameters");
        return ESP_FAIL;
    }
    free(content);

    if (low_value >= up_value) {
        httpd_resp_send_err(req, HTTPD_400_BAD_REQUEST, "Low value must be less than up value");
        return ESP_FAIL;
    }

    atomic_store(&g_threshold_low, low_value);
    atomic_store(&g_threshold_up, up_value);

    return send_json_response(req, "{\"success\":true,\"low\":%d,\"up\":%d}", low_value, up_value);
}

void wifi_init_softap(void) {
    ESP_ERROR_CHECK(esp_netif_init());
    ESP_ERROR_CHECK(esp_event_loop_create_default());
    esp_netif_t *ap_netif = esp_netif_create_default_wifi_ap();

    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(esp_wifi_init(&cfg));

    wifi_config_t wifi_config = {
        .ap = {
            .ssid = CONFIG_AP_WIFI_SSID,
            .ssid_len = strlen(CONFIG_AP_WIFI_SSID),
            .password = CONFIG_AP_WIFI_PASS,
            .max_connection = AP_MAX_CONN,
            .authmode = WIFI_AUTH_WPA_WPA2_PSK,
            .channel = AP_CHANNEL,
        },
    };

    if (strlen(CONFIG_AP_WIFI_PASS) == 0) {
        wifi_config.ap.authmode = WIFI_AUTH_OPEN;
    }

    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_AP));
    ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_AP, &wifi_config));
    ESP_ERROR_CHECK(esp_wifi_start());

    esp_netif_ip_info_t ip_info;
    ip_info.ip.addr = ipaddr_addr(CONFIG_AP_IP);
    ip_info.gw.addr = ipaddr_addr(CONFIG_AP_GATEWAY);
    ip_info.netmask.addr = ipaddr_addr(CONFIG_AP_NETMASK);

    ESP_ERROR_CHECK(esp_netif_dhcps_stop(ap_netif));
    ESP_ERROR_CHECK(esp_netif_set_ip_info(ap_netif, &ip_info));
    ESP_ERROR_CHECK(esp_netif_dhcps_start(ap_netif));
}

static void pump_disable(void) {
    gpio_set_level(CONFIG_PUMP_PIN, false);
}

static void pump_enable(void) {
    gpio_set_level(CONFIG_PUMP_PIN, true);
}

static void vPumpControlTask(void *pvParameters) {
    while (1) {
        int current_pressure = atomic_load(&g_current_pressure);
        int low_threshold = atomic_load(&g_threshold_low);
        int up_threshold = atomic_load(&g_threshold_up);

        if (current_pressure < low_threshold) {
            pump_enable();
            ESP_LOGI(TAG, "Pump enabled");
        } else if (current_pressure >= up_threshold) {
            pump_disable();
            ESP_LOGI(TAG, "Pump disabled");
        }
        vTaskDelay(pdMS_TO_TICKS(1000));
    }
}

static int read_pressure_filtered(void) {
    int sum = 0;
    for (int i = 0; i < FILTER_SAMPLES; i++) {
        sum += adc_read_voltage(SENSOR_ADC_CHAN);
        vTaskDelay(pdMS_TO_TICKS(10));
    }
    return sum / FILTER_SAMPLES;
}

static void vReadSensorTask(void *pvParameters) {
    esp_task_wdt_add(NULL);
    while (1) {
        int pressure = read_pressure_filtered();
        atomic_store(&g_current_pressure, pressure);

        esp_task_wdt_reset();

        vTaskDelay(pdMS_TO_TICKS(1000));
    }
}

static void register_http_handlers(httpd_handle_t server) {
    httpd_uri_t root = {
        .uri       = "/",
        .method    = HTTP_GET,
        .handler   = root_get_handler,
        .user_ctx  = NULL
    };
    httpd_register_uri_handler(server, &root);

    httpd_uri_t pressure = {
        .uri       = "/pressure",
        .method    = HTTP_GET,
        .handler   = current_pressure_handler,
        .user_ctx  = NULL
    };
    httpd_register_uri_handler(server, &pressure);

    httpd_uri_t set_thresholds = {
        .uri       = "/thresholds",
        .method    = HTTP_POST,
        .handler   = set_thresholds_handler,
        .user_ctx  = NULL
    };
    httpd_register_uri_handler(server, &set_thresholds);

    httpd_uri_t save_thresholds = {
        .uri       = "/persist_thresholds",
        .method    = HTTP_POST,
        .handler   = save_thresholds_handler,
        .user_ctx  = NULL
    };
    httpd_register_uri_handler(server, &save_thresholds);
}

static void vHttpServerTask(void *pvParameters) {
    esp_task_wdt_add(xTaskGetCurrentTaskHandle());

    httpd_handle_t server = NULL;
    httpd_config_t config = HTTPD_DEFAULT_CONFIG();
    config.server_port = CONFIG_WEBINTERFACE_PORT;
    config.max_uri_handlers = 10;
    config.stack_size = 4096;

    if (httpd_start(&server, &config) == ESP_OK) {
        ESP_LOGI(TAG, "🚀 HTTP server run on port %d", config.server_port);
        register_http_handlers(server);
    } else {
        ESP_LOGE(TAG, "❌Error HTTP server running");
    }

    while (1) {
        esp_task_wdt_reset();
        vTaskDelay(pdMS_TO_TICKS(1000));
    }
}

static void load_thresholds_from_nvs(void) {
    nvs_handle_t my_handle;
    esp_err_t err = nvs_open(NVS_PARTITION, NVS_READWRITE, &my_handle);
    if (err != ESP_OK) {
        ESP_LOGE(TAG, "Error opening NVS");
        return;
    }

    int32_t threshold_low = 0;
    err = nvs_get_i32(my_handle, THRESHOLD_LOW_NVS_NAME, &threshold_low);
    if (err == ESP_OK) {
        atomic_store(&g_threshold_low, threshold_low);
    } else if (err == ESP_ERR_NVS_NOT_FOUND) {
        atomic_store(&g_threshold_low, 100);
    } else {
        ESP_ERROR_CHECK(err);
    }

    int32_t threshold_up = 0;
    err = nvs_get_i32(my_handle, THRESHOLD_UP_NVS_NAME, &threshold_up);
    if (err == ESP_OK) {
        atomic_store(&g_threshold_up, threshold_up);
    } else if (err == ESP_ERR_NVS_NOT_FOUND) {
        atomic_store(&g_threshold_up, 300);
    } else {
        ESP_ERROR_CHECK(err);
    }

    nvs_close(my_handle);
}

void app_main(void) {
    esp_err_t ret = nvs_flash_init();
    if (ret == ESP_ERR_NVS_NO_FREE_PAGES || ret == ESP_ERR_NVS_NEW_VERSION_FOUND) {
        ESP_ERROR_CHECK(nvs_flash_erase());
        ret = nvs_flash_init();
    }
    ESP_ERROR_CHECK(ret);

    esp_task_wdt_config_t twdt_config = {
        .timeout_ms = 10000,           // 10 секунд таймаут
        .idle_core_mask = (1 << 0) | (1 << 1), // Мониторинг idle-задач на обоих ядрах
        .trigger_panic = true           // Паника при таймауте (перезагрузка)
    };
    ESP_ERROR_CHECK(esp_task_wdt_init(&twdt_config));

    // Добавляем main задачу
    ESP_ERROR_CHECK(esp_task_wdt_add(NULL));



    load_thresholds_from_nvs();
    adc_init();
    pump_init();
    wifi_init_softap();

    vTaskDelay(pdMS_TO_TICKS(1000));

    xTaskCreate(vReadSensorTask, "read_sensor", 2048, NULL, PRIORITY_SENSOR, NULL);
    xTaskCreate(vPumpControlTask, "pump_control", 2048, NULL, PRIORITY_CONTROL, NULL);
    xTaskCreate(vHttpServerTask, "http_server", 4096, NULL, PRIORITY_HTTP, NULL);

    ESP_LOGI(TAG, "=========================================");
    ESP_LOGI(TAG, "✅ Ready to work");
    ESP_LOGI(TAG, "📱 Connect to Wi-Fi: %s", CONFIG_AP_WIFI_SSID);
    ESP_LOGI(TAG, "🔑 Wi-Fi Password: %s", strlen(CONFIG_AP_WIFI_PASS) ? CONFIG_AP_WIFI_PASS : "Open network");
    ESP_LOGI(TAG, "🌐 Open browser: http://%s:%d", CONFIG_AP_IP, CONFIG_WEBINTERFACE_PORT);
    ESP_LOGI(TAG, "=========================================");

    while (1) {
        vTaskDelay(pdMS_TO_TICKS(5000));

        wifi_sta_list_t sta_list;
        memset(&sta_list, 0, sizeof(sta_list));
        esp_wifi_ap_get_sta_list(&sta_list);

        ESP_LOGI(TAG, "📊 Wi-Fi Clients connected: %d", sta_list.num);
    }
}