#include "ota.h"
#include "http.h"
#include "json.h"
#include "log.h"
#include "timer.h"
#include "url.h"
#include "util.h"

enum { MG_OTA_STATUS_WAITING, MG_OTA_STATUS_SUCCESS, MG_OTA_STATUS_FAIL };
static int s_version_status;
static int s_ota_status;
static uint64_t s_start_time;

static struct mg_ota_metadata {
  char *version;
  char *url;
  size_t size;
  uint8_t sha256[32];
} s_ota_metadata;

static void free_ota_metadata(void) {
  if (s_ota_metadata.version) mg_free(s_ota_metadata.version);
  if (s_ota_metadata.url) mg_free(s_ota_metadata.url);
  memset(&s_ota_metadata, 0, sizeof(s_ota_metadata));
}

static int fetch_ota_metadata(struct mg_http_message *response) {
  double result;
  if (mg_http_status(response) != 200) goto fetch_failed;
  if (mg_json_get(response->body, "$", NULL) != 0) goto fetch_failed;
  free_ota_metadata();
  s_ota_metadata.version = mg_json_get_str(response->body, "$.version");
  if (s_ota_metadata.version == NULL) goto fetch_failed;
  s_ota_metadata.url = mg_json_get_str(response->body, "$.url");
  if (s_ota_metadata.url == NULL) goto fetch_failed;
  if (!mg_json_get_num(response->body, "$.size", &result) || result <= 0)
    goto fetch_failed;
  s_ota_metadata.size = (size_t) result;
  // TODO (robertc2000): parse and validate sha256
  MG_DEBUG(("Firmware version: %s, url: %s, size: %ld", s_ota_metadata.version,
            s_ota_metadata.url, s_ota_metadata.size));
  return MG_OTA_STATUS_SUCCESS;
fetch_failed:
  free_ota_metadata();
  return MG_OTA_STATUS_FAIL;
}

static void s_version_fn(struct mg_connection *c, int ev, void *ev_data) {
  struct mg_str host = mg_url_host((char *) c->fn_data);
  struct mg_http_message *hm;
  static int fetch_status;

  if (ev == MG_EV_POLL) {
    if (s_start_time + 5 * 1000 < mg_millis()) {
      mg_error(c, "Connection timeout");
    }
  } else if (ev == MG_EV_CONNECT) {
    mg_printf(c,
              "GET %s HTTP/1.1\r\n"
              "Host: %.*s\r\n"
              "Connection: close\r\n\r\n",
              mg_url_uri((char *) c->fn_data), (int) host.len, host.buf);
    fetch_status = MG_OTA_STATUS_WAITING;
  } else if (ev == MG_EV_HTTP_MSG) {
    hm = (struct mg_http_message *) ev_data;
    fetch_status = fetch_ota_metadata(hm);
  } else if (ev == MG_EV_ERROR) {
    MG_ERROR(("%lu Connection error", c->id));
    s_version_status = MG_OTA_STATUS_FAIL;
  } else if (ev == MG_EV_CLOSE) {
    MG_DEBUG(("%lu Connection closed %lu", c->id, mg_millis() - s_start_time));
    s_version_status = fetch_status;
  }
}

static void s_ota_done(struct mg_connection *c, const char *errmsg) {
  (void) c;
  s_ota_status = errmsg ? MG_OTA_STATUS_FAIL : MG_OTA_STATUS_SUCCESS;
  if (errmsg) MG_ERROR(("OTA failed: %s", errmsg));
}

static void s_firmware_fn(struct mg_connection *c, int ev, void *ev_data) {
  struct mg_str host = mg_url_host(s_ota_metadata.url);
  if (ev == MG_EV_POLL) {
    if (s_start_time + 120 * 1000 < mg_millis()) mg_error(c, "Timeout");
  } else if (ev == MG_EV_CONNECT) {
    mg_printf(c,
              "GET %s HTTP/1.1\r\n"
              "Host: %.*s\r\n"
              "Connection: close\r\n\r\n",
              mg_url_uri(s_ota_metadata.url), (int) host.len, host.buf);
  } else if (ev == MG_EV_HTTP_HDRS) {
    struct mg_http_message *hm = (struct mg_http_message *) ev_data;
    int status = mg_http_status(hm);
    if (status != 200 || hm->body.len != s_ota_metadata.size) {
      mg_error(c, "Bad HTTP response: status %d, size %lu vs %lu", status,
               (unsigned long) hm->body.len,
               (unsigned long) s_ota_metadata.size);
      s_ota_status = MG_OTA_STATUS_FAIL;
      return;
    }
    MG_DEBUG(
        ("Beginning OTA (%lu bytes)", (unsigned long) s_ota_metadata.size));
    mg_http_start_ota(c, hm, s_ota_done);
  } else if (ev == MG_EV_ERROR) {
    MG_ERROR(("%lu Connection error", c->id));
    s_ota_status = MG_OTA_STATUS_FAIL;
  }
  (void) ev_data;
}

void mg_ota_url_check(struct mg_mgr *mgr, const char *current_version,
                      const char *metadata_url,
                      void (*fn)(const char *status)) {
  s_version_status = MG_OTA_STATUS_WAITING;
  s_ota_status = MG_OTA_STATUS_WAITING;
  s_start_time = mg_millis();
  MG_DEBUG(("Connecting to %s to retrieve metadata", metadata_url));
  if (!mg_http_connect(mgr, metadata_url, s_version_fn,
                       (void *) metadata_url)) {
    if (fn) fn("Failed to connect");
    return;
  }
  while (s_version_status == MG_OTA_STATUS_WAITING) mg_mgr_poll(mgr, 10);
  if (s_version_status == MG_OTA_STATUS_SUCCESS) {
    if (strcmp(s_ota_metadata.version, current_version) == 0) {
      if (fn) fn("Same version");
      free_ota_metadata();
      return;
    }
  } else {
    if (fn) fn("Version retrieving error");
    free_ota_metadata();
    return;
  }
  if (fn) fn("Pulling firmware");
  s_start_time = mg_millis();
  MG_DEBUG(("Connecting to %s to download firmware", s_ota_metadata.url));
  if (!mg_http_connect(mgr, s_ota_metadata.url, s_firmware_fn, NULL)) {
    if (fn) fn("Failed to connect");
    free_ota_metadata();
    return;
  }
  while (s_ota_status == MG_OTA_STATUS_WAITING) mg_mgr_poll(mgr, 10);
  if (s_ota_status == MG_OTA_STATUS_FAIL && fn) fn("OTA fail");
  free_ota_metadata();
}