#include "esp_tls.h"
#include "esp_log.h"
#include <string.h>
#include "freertos/FreeRTOS.h"

#include "esp_crt_bundle.h"

static const char *TAG = "https";

#define WEB_SERVER "bsvg.efa.de"
#define WEB_PORT "443"
#define WEB_URL "/bsvagstd/XML_DM_REQUEST?outputFormat=JSON&stateless=1&locationServerActive=1&type_dm=stop&name_dm=\"Freiastr,Braunschweig\"&mode=direct&ptOptionsActive=1&useRealtime=1"

static const char HOWSMYSSL_REQUEST[] = "GET " WEB_URL " HTTP/1.1\r\n"
                             "Host: "WEB_SERVER"\r\n"
                             "User-Agent: esp-idf/1.0 esp32\r\n"
                             "\r\n";

static void https_get_request(esp_tls_cfg_t cfg, const char *WEB_SERVER_URL, const char *REQUEST)
{
    char buf[47000];
    int ret, len;

    esp_tls_t *tls = esp_tls_init();
    if (!tls) {
        ESP_LOGE(TAG, "Failed to allocate esp_tls handle!");
        goto exit;
    }

    if (esp_tls_conn_http_new_sync(WEB_SERVER_URL, &cfg, tls) == 1) {
        ESP_LOGI(TAG, "Connection established...");
    } else {
        ESP_LOGE(TAG, "Connection failed...");
        int esp_tls_code = 0, esp_tls_flags = 0;
        esp_tls_error_handle_t tls_e = NULL;
        esp_tls_get_error_handle(tls, &tls_e);
        /* Try to get TLS stack level error and certificate failure flags, if any */
        ret = esp_tls_get_and_clear_last_error(tls_e, &esp_tls_code, &esp_tls_flags);
        if (ret == ESP_OK) {
            ESP_LOGE(TAG, "TLS error = -0x%x, TLS flags = -0x%x", esp_tls_code, esp_tls_flags);
        }
        goto cleanup;
    }

#ifdef CONFIG_EXAMPLE_CLIENT_SESSION_TICKETS
    /* The TLS session is successfully established, now saving the session ctx for reuse */
    if (save_client_session) {
        esp_tls_free_client_session(tls_client_session);
        tls_client_session = esp_tls_get_client_session(tls);
    }
#endif

    size_t written_bytes = 0;
    do {
        ret = esp_tls_conn_write(tls,
                                 REQUEST + written_bytes,
                                 strlen(REQUEST) - written_bytes);
        if (ret >= 0) {
            ESP_LOGI(TAG, "%d bytes written", ret);
            written_bytes += ret;
        } else if (ret != ESP_TLS_ERR_SSL_WANT_READ  && ret != ESP_TLS_ERR_SSL_WANT_WRITE) {
            ESP_LOGE(TAG, "esp_tls_conn_write  returned: [0x%02X](%s)", ret, esp_err_to_name(ret));
            goto cleanup;
        }
    } while (written_bytes < strlen(REQUEST));

    ESP_LOGI(TAG, "Reading HTTP response...");
    do {
        len = sizeof(buf) - 1;
        memset(buf, 0x00, sizeof(buf));
        ret = esp_tls_conn_read(tls, (char *)buf, len);

        if (ret == ESP_TLS_ERR_SSL_WANT_WRITE  || ret == ESP_TLS_ERR_SSL_WANT_READ) {
            continue;
        } else if (ret < 0) {
            ESP_LOGE(TAG, "esp_tls_conn_read  returned [-0x%02X](%s)", -ret, esp_err_to_name(ret));
            break;
        } else if (ret == 0) {
            ESP_LOGI(TAG, "connection closed");
            break;
        }

        len = ret;
        ESP_LOGD(TAG, "%d bytes read", len);
        /* Print response directly to stdout as it is read */
        for (int i = 0; i < len; i++) {
            putchar(buf[i]);
        }
        putchar('\n'); // JSON output doesn't have a newline at end
    } while (1);

cleanup:
    esp_tls_conn_destroy(tls);
exit:
    for (int countdown = 10; countdown >= 0; countdown--) {
        ESP_LOGI(TAG, "%d...", countdown);
        vTaskDelay(1000 / portTICK_PERIOD_MS);
    }
}

void https_get_request_using_crt_bundle(void)
{
    ESP_LOGI(TAG, "https_request using crt bundle");
    esp_tls_cfg_t cfg = {
        .crt_bundle_attach = esp_crt_bundle_attach,
    };
    https_get_request(cfg, "https://"WEB_SERVER""WEB_URL, HOWSMYSSL_REQUEST);
}