#include "wifi_manager.h"
#include "mimi_config.h"

#include <string.h>
#include <inttypes.h>
#include "esp_log.h"
#include "esp_wifi.h"
#include "esp_netif.h"
#include "nvs_flash.h"
#include "nvs.h"

static const char *TAG = "wifi";

static EventGroupHandle_t s_wifi_event_group;
static int s_retry_count = 0;
static char s_ip_str[16] = "0.0.0.0";
static bool s_connected = false;

static void 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_START) {
        esp_wifi_connect();
    } else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_DISCONNECTED) {
        s_connected = false;
        if (s_retry_count < MIMI_WIFI_MAX_RETRY) {
            /* Exponential backoff: 1s, 2s, 4s, 8s, ... capped at 30s */
            uint32_t delay_ms = MIMI_WIFI_RETRY_BASE_MS << s_retry_count;
            if (delay_ms > MIMI_WIFI_RETRY_MAX_MS) {
                delay_ms = MIMI_WIFI_RETRY_MAX_MS;
            }
            ESP_LOGW(TAG, "Disconnected, retry %d/%d in %" PRIu32 "ms",
                     s_retry_count + 1, MIMI_WIFI_MAX_RETRY, delay_ms);
            vTaskDelay(pdMS_TO_TICKS(delay_ms));
            esp_wifi_connect();
            s_retry_count++;
        } else {
            ESP_LOGE(TAG, "Failed to connect after %d retries", MIMI_WIFI_MAX_RETRY);
            xEventGroupSetBits(s_wifi_event_group, WIFI_FAIL_BIT);
        }
    } else if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP) {
        ip_event_got_ip_t *event = (ip_event_got_ip_t *)event_data;
        snprintf(s_ip_str, sizeof(s_ip_str), IPSTR, IP2STR(&event->ip_info.ip));
        ESP_LOGI(TAG, "Connected! IP: %s", s_ip_str);
        s_retry_count = 0;
        s_connected = true;
        xEventGroupSetBits(s_wifi_event_group, WIFI_CONNECTED_BIT);
    }
}

esp_err_t wifi_manager_init(void)
{
    s_wifi_event_group = xEventGroupCreate();

    ESP_ERROR_CHECK(esp_netif_init());
    esp_netif_create_default_wifi_sta();

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

    ESP_ERROR_CHECK(esp_event_handler_instance_register(
        WIFI_EVENT, ESP_EVENT_ANY_ID, &event_handler, NULL, NULL));
    ESP_ERROR_CHECK(esp_event_handler_instance_register(
        IP_EVENT, IP_EVENT_STA_GOT_IP, &event_handler, NULL, NULL));

    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA));

    ESP_LOGI(TAG, "WiFi manager initialized");
    return ESP_OK;
}

esp_err_t wifi_manager_start(void)
{
    wifi_config_t wifi_cfg = {0};

    /* Build-time secrets take highest priority */
    if (MIMI_SECRET_WIFI_SSID[0] != '\0') {
        strncpy((char *)wifi_cfg.sta.ssid, MIMI_SECRET_WIFI_SSID, sizeof(wifi_cfg.sta.ssid) - 1);
        strncpy((char *)wifi_cfg.sta.password, MIMI_SECRET_WIFI_PASS, sizeof(wifi_cfg.sta.password) - 1);
    } else {
        /* Fall back to NVS */
        nvs_handle_t nvs;
        esp_err_t err = nvs_open(MIMI_NVS_WIFI, NVS_READONLY, &nvs);
        if (err != ESP_OK) {
            ESP_LOGW(TAG, "No WiFi credentials. Use CLI: wifi_set <SSID> <PASS>");
            return ESP_ERR_NOT_FOUND;
        }

        size_t len = sizeof(wifi_cfg.sta.ssid);
        err = nvs_get_str(nvs, MIMI_NVS_KEY_SSID, (char *)wifi_cfg.sta.ssid, &len);
        if (err != ESP_OK) {
            nvs_close(nvs);
            ESP_LOGW(TAG, "SSID not found in NVS");
            return ESP_ERR_NOT_FOUND;
        }

        len = sizeof(wifi_cfg.sta.password);
        nvs_get_str(nvs, MIMI_NVS_KEY_PASS, (char *)wifi_cfg.sta.password, &len);
        nvs_close(nvs);
    }

    ESP_LOGI(TAG, "Connecting to SSID: %s", wifi_cfg.sta.ssid);

    ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, &wifi_cfg));
    ESP_ERROR_CHECK(esp_wifi_start());

    return ESP_OK;
}

esp_err_t wifi_manager_wait_connected(uint32_t timeout_ms)
{
    TickType_t ticks = (timeout_ms == UINT32_MAX) ? portMAX_DELAY : pdMS_TO_TICKS(timeout_ms);
    EventBits_t bits = xEventGroupWaitBits(
        s_wifi_event_group, WIFI_CONNECTED_BIT | WIFI_FAIL_BIT,
        pdFALSE, pdFALSE, ticks);

    if (bits & WIFI_CONNECTED_BIT) {
        return ESP_OK;
    }
    return ESP_ERR_TIMEOUT;
}

bool wifi_manager_is_connected(void)
{
    return s_connected;
}

esp_err_t wifi_manager_set_credentials(const char *ssid, const char *password)
{
    nvs_handle_t nvs;
    ESP_ERROR_CHECK(nvs_open(MIMI_NVS_WIFI, NVS_READWRITE, &nvs));
    ESP_ERROR_CHECK(nvs_set_str(nvs, MIMI_NVS_KEY_SSID, ssid));
    ESP_ERROR_CHECK(nvs_set_str(nvs, MIMI_NVS_KEY_PASS, password));
    ESP_ERROR_CHECK(nvs_commit(nvs));
    nvs_close(nvs);
    ESP_LOGI(TAG, "WiFi credentials saved for SSID: %s", ssid);
    return ESP_OK;
}

const char *wifi_manager_get_ip(void)
{
    return s_ip_str;
}

EventGroupHandle_t wifi_manager_get_event_group(void)
{
    return s_wifi_event_group;
}