/* L1 driver diagnosis: the device becomes its own access point.
 *
 * Ladder (docs/architecture.md): prove each layer before climbing.
 *   L0 SDIO control path      — proven (RPC works)
 *   L1 wifi data path AT ALL  — this file: SoftAP + DHCP + HTTP, no external network
 *   L2 STA to any network     — phone hotspot
 *   L3 STA to "Outside"       — the real network
 *   L4 gateway + Tatlock      — only after L3
 *
 * Join DESKLOCK-DIAG (pass desklock123) with a phone:
 *   - association          -> log + on-screen counter
 *   - DHCP lease from us   -> IP_EVENT_AP_STAIPASSIGNED = SDIO data path PROVEN
 *   - http://192.168.4.1/  -> full TCP round trip PROVEN
 */

#include <stdio.h>

#include "esp_event.h"
#include "esp_http_server.h"
#include "esp_log.h"
#include "esp_netif.h"
#include "esp_wifi.h"
#include "nvs_flash.h"

#include "desklock.h"

static const char *TAG = "wifidiag";

static int s_assoc;
static int s_leases;
static int s_http_hits;

static void show(void)
{
    char line[96];
    snprintf(line, sizeof(line), "DIAG AP: assoc %d | lease %d | http %d",
             s_assoc, s_leases, s_http_hits);
    face_status(line);
    ESP_LOGI(TAG, "%s", line);
}

static void diag_event(void *arg, esp_event_base_t base, int32_t id, void *data)
{
    (void)arg;
    (void)data;
    if (base == WIFI_EVENT && id == WIFI_EVENT_AP_STACONNECTED) {
        s_assoc++;
        ESP_LOGI(TAG, "L1a: station ASSOCIATED (radio + auth OK)");
    } else if (base == WIFI_EVENT && id == WIFI_EVENT_AP_STADISCONNECTED) {
        if (s_assoc > 0) {
            s_assoc--;
        }
    } else if (base == IP_EVENT && id == IP_EVENT_AP_STAIPASSIGNED) {
        s_leases++;
        ESP_LOGI(TAG, "L1b: DHCP LEASE ASSIGNED — SDIO DATA PATH PROVEN");
    }
    show();
}

static esp_err_t hello_get(httpd_req_t *req)
{
    s_http_hits++;
    ESP_LOGI(TAG, "L1c: HTTP GET — FULL TCP ROUND TRIP PROVEN");
    show();
    return httpd_resp_sendstr(req, "desklock diag: data path OK\n");
}

void wifi_diag_start(void)
{
    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());
        ESP_ERROR_CHECK(nvs_flash_init());
    }
    ESP_ERROR_CHECK(esp_netif_init());
    ESP_ERROR_CHECK(esp_event_loop_create_default());
    esp_netif_create_default_wifi_ap();

    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(esp_wifi_init(&cfg));
    ESP_ERROR_CHECK(esp_event_handler_register(WIFI_EVENT, ESP_EVENT_ANY_ID, diag_event, NULL));
    ESP_ERROR_CHECK(esp_event_handler_register(IP_EVENT, IP_EVENT_AP_STAIPASSIGNED, diag_event, NULL));

    wifi_config_t ap = {
        .ap = {
            .ssid = "DESKLOCK-DIAG",
            .password = "desklock123",
            .authmode = WIFI_AUTH_WPA2_PSK,
            .max_connection = 4,
            .channel = 6,
        },
    };
    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_AP));
    ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_AP, &ap));
    ESP_ERROR_CHECK(esp_wifi_start());

    httpd_handle_t server = NULL;
    httpd_config_t hcfg = HTTPD_DEFAULT_CONFIG();
    if (httpd_start(&server, &hcfg) == ESP_OK) {
        static const httpd_uri_t root = { .uri = "/", .method = HTTP_GET, .handler = hello_get };
        httpd_register_uri_handler(server, &root);
    } else {
        ESP_LOGE(TAG, "httpd_start failed");
        face_status("DIAG: httpd FAILED");
    }

    ESP_LOGI(TAG, "L1 diag AP up: join DESKLOCK-DIAG / desklock123, open http://192.168.4.1/");
    face_status("DIAG: join DESKLOCK-DIAG");
}