#include "sys_wifi.h"
#include "web_server.h"
#include "os_event.h"
#include "os_status.h"
#include "sdkconfig.h"
#include "esp_event.h"
#include "esp_log.h"
#include "esp_netif.h"
#include "esp_wifi.h"
#include "nvs.h"
#include "nvs_flash.h"
#include <stdio.h>
#include <string.h>

static const char *TAG = "SYS_WIFI";
static esp_netif_t *s_sta_netif;
static esp_netif_t *s_ap_netif;
static char s_sta_ssid[33];
static char s_sta_password[65];

static void copy_wifi_string(uint8_t *destination, size_t destination_size, const char *source)
{
    size_t length = strlen(source);
    if (length >= destination_size) length = destination_size - 1;
    memcpy(destination, source, length);
    destination[length] = '\0';
}

static void set_status(wifi_state_t state, int8_t rssi)
{
    sys_status_set_wifi(state, rssi);
    sys_event_post(SYS_EVENT_WIFI_STATUS_CHANGED, (int32_t)state, NULL);
}

static esp_err_t load_credentials(void)
{
    nvs_handle_t nvs;
    size_t ssid_len = sizeof(s_sta_ssid);
    size_t password_len = sizeof(s_sta_password);
    esp_err_t err = nvs_open("wifi", NVS_READONLY, &nvs);
    if (err != ESP_OK) return err;
    err = nvs_get_str(nvs, "ssid", s_sta_ssid, &ssid_len);
    if (err == ESP_OK) err = nvs_get_str(nvs, "password", s_sta_password, &password_len);
    nvs_close(nvs);
    return err;
}

static void start_softap(void)
{
    wifi_config_t ap_config = {0};
    copy_wifi_string(ap_config.ap.ssid, sizeof(ap_config.ap.ssid), CONFIG_SYS_WIFI_AP_SSID);
    copy_wifi_string(ap_config.ap.password, sizeof(ap_config.ap.password), CONFIG_SYS_WIFI_AP_PASSWORD);
    ap_config.ap.authmode = WIFI_AUTH_WPA2_PSK;
    ap_config.ap.max_connection = 2;
    esp_wifi_set_mode(WIFI_MODE_APSTA);
    esp_wifi_set_config(WIFI_IF_AP, &ap_config);
    esp_wifi_start();
    set_status(WIFI_STATE_AP_MODE, 0);
    web_server_start();
    ESP_LOGI(TAG, "Provisioning AP '%s', browse to http://192.168.4.1", CONFIG_SYS_WIFI_AP_SSID);
}

static void start_station(void)
{
    wifi_config_t config = {0};
    copy_wifi_string(config.sta.ssid, sizeof(config.sta.ssid), s_sta_ssid);
    copy_wifi_string(config.sta.password, sizeof(config.sta.password), s_sta_password);
    esp_wifi_set_mode(WIFI_MODE_STA);
    esp_wifi_set_config(WIFI_IF_STA, &config);
    esp_wifi_start();
    set_status(WIFI_STATE_CONNECTING, 0);
    esp_wifi_connect();
    ESP_LOGI(TAG, "Connecting to Wi-Fi network '%s'", s_sta_ssid);
}

static void wifi_event_handler(void *arg, esp_event_base_t event_base, int32_t event_id, void *event_data)
{
    if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_DISCONNECTED) {
        set_status(WIFI_STATE_CONNECTING, 0);
        esp_wifi_connect();
    } else if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP) {
        wifi_ap_record_t record;
        int8_t rssi = 0;
        if (esp_wifi_sta_get_ap_info(&record) == ESP_OK) rssi = record.rssi;
        set_status(WIFI_STATE_CONNECTED, rssi);
        web_server_start();
        const ip_event_got_ip_t *got_ip = (const ip_event_got_ip_t *)event_data;
        ESP_LOGI(TAG, "Wi-Fi connected, web server at http://" IPSTR, IP2STR(&got_ip->ip_info.ip));
    }
}

esp_err_t sys_wifi_clear_credentials(void)
{
    nvs_handle_t nvs;
    esp_err_t err = nvs_open("wifi", NVS_READWRITE, &nvs);
    if (err != ESP_OK) return err;
    err = nvs_erase_all(nvs);
    if (err == ESP_OK) err = nvs_commit(nvs);
    nvs_close(nvs);
    return err;
}

esp_err_t sys_wifi_init(void)
{
#if !CONFIG_SYS_WIFI_ENABLED
    set_status(WIFI_STATE_OFF, 0);
    return ESP_OK;
#else
    esp_err_t err = nvs_flash_init();
    if (err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
        ESP_ERROR_CHECK(nvs_flash_erase());
        err = nvs_flash_init();
    }
    if (err != ESP_OK) return err;

    err = esp_netif_init();
    if (err != ESP_OK && err != ESP_ERR_INVALID_STATE) return err;
    err = esp_event_loop_create_default();
    if (err != ESP_OK && err != ESP_ERR_INVALID_STATE) return err;
    s_sta_netif = esp_netif_create_default_wifi_sta();
    s_ap_netif = esp_netif_create_default_wifi_ap();
    if (!s_sta_netif || !s_ap_netif) return ESP_ERR_NO_MEM;

    wifi_init_config_t wifi_config = WIFI_INIT_CONFIG_DEFAULT();
    err = esp_wifi_init(&wifi_config);
    if (err != ESP_OK) return err;
    ESP_ERROR_CHECK(esp_event_handler_register(WIFI_EVENT, ESP_EVENT_ANY_ID, &wifi_event_handler, NULL));
    ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT, IP_EVENT_STA_GOT_IP, &wifi_event_handler, NULL));

    if (load_credentials() == ESP_OK && s_sta_ssid[0] != '\0' && s_sta_password[0] != '\0') {
        start_station();
    } else {
        start_softap();
    }
    return ESP_OK;
#endif
}