#include "version.h"
#include "digest/digest.h"
#include "l2su.h"
#include "macros.h"
#include "endian.h"
#include "command.h"

#include <curl/curl.h>
#include <curl/easy.h>
#include <curl/header.h>
#include <jansson.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <alloca.h>

const char *const l2_version__messages[] = {
  "Success",
  "Malformed version manifest",
  "Version manifest JSON error",
  "Allocation failed",
  "OS error",
  "An unspecified error has occurred",
  NULL
};

#define L2_VERSION_MANIFEST_ETAG_PATH "/.l2_vermanifest_etag"
#define L2_VERSION_MANIFEST_PATH "version_manifest_v2.json"
#define L2_VERSION_MANIFEST_EXP_TIME ((time_t)120)

unsigned l2_version__download_manifest(json_t **out_json);
unsigned l2_version__load_all_from_json(json_t *json);

unsigned l2_version__add_remote(json_t *obj);

unsigned l2_version_load_remote(void)
{
  json_t *vers;
  return l2_version__download_manifest(&vers);
}

unsigned l2_version_load_local(void)
{
  return VERSION_SUCCESS;
}

char *l2_version__read_etag(time_t *lastmod)
{
  size_t dpathlen = strlen(l2_state.paths.data);
  char *etagpath;

  L2_ASTRCAT2(etagpath, l2_state.paths.data, dpathlen, L2_VERSION_MANIFEST_ETAG_PATH, L2_CSTRLEN(L2_VERSION_MANIFEST_ETAG_PATH));

  FILE *etagfp = fopen(etagpath, "rb");
  char *etag = NULL;
  uint32_t buf;
  uint64_t ts;

  if (!etagfp) return NULL;
  if (fread(&buf, sizeof(uint32_t), 1, etagfp) < sizeof(uint32_t)) goto cleanup;
  if (fread(&ts, sizeof(uint64_t), 1, etagfp) < sizeof(uint64_t)) goto cleanup;

  buf = l2_betoh32(buf);
  ts = l2_betoh64(ts);

  etag = calloc(buf + 1, 1);
  if (!etag) goto cleanup;

  if (fread(etag, 1, buf, etagfp) < buf) goto cleanup;
  etag[buf] = '\0';

  *lastmod = (time_t)ts;

  fclose(etagfp);

  return etag;

cleanup:
  free(etag);
  fclose(etagfp);
  return NULL;
}

/* this function does not report errors on failure because its operation is not essential */
void l2_version__write_etag(time_t modtime, const char *etag)
{
  size_t dpathlen = strlen(l2_state.paths.data);
  char *etagpath;

  L2_ASTRCAT2(etagpath, l2_state.paths.data, dpathlen, L2_VERSION_MANIFEST_ETAG_PATH, L2_CSTRLEN(L2_VERSION_MANIFEST_ETAG_PATH));

  uint32_t etaglen = l2_betoh32((uint32_t)strlen(etag));
  uint64_t mt_write = l2_betoh64((uint64_t)modtime);

  FILE *etagfp = fopen(etagpath, "wb");
  if (!etagfp) return;

  if (fwrite(&etaglen, sizeof(uint32_t), 1, etagfp) < sizeof(uint32_t)) goto cleanup;
  if (fwrite(&mt_write, sizeof(uint64_t), 1, etagfp) < sizeof(uint64_t)) goto cleanup;
  if (fwrite(etag, 1, etaglen, etagfp) < etaglen) goto cleanup;

cleanup:
  fclose(etagfp);
}

int l2_version__read_manifest_file(json_t **manifest)
{
  size_t dpathlen = strlen(l2_state.paths.data);
  char *manpath;

  L2_ASTRCAT2(manpath, l2_state.paths.data, dpathlen, L2_VERSION_MANIFEST_PATH, L2_CSTRLEN(L2_VERSION_MANIFEST_PATH));

  json_error_t err;
  json_t *man = json_load_file(manpath, JSON_REJECT_DUPLICATES, &err);
  if (!man) {
    CMD_WARN("Error loading manifest file: %s\n", err.text);
    return -1;
  }

  *manifest = man;
  return 0;
}

#if 0
unsigned l2_version__download_manifest(json_t **out_versions)
{
  unsigned ret = VERSION_SUCCESS;
  CURL *pc = NULL;
  FILE *outfile = NULL;
  void *verdata = NULL;
  int en;

  struct curl_slist *headers = NULL;

  time_t lastmod;
  char *etag = l2_version__read_etag(&lastmod);

  if (etag) {
    if (lastmod + L2_VERSION_MANIFEST_EXP_TIME > time(NULL)) {
      /* no need to redownload */
      *out_versions = NULL;
      return VERSION_SUCCESS;
    }
  }

  pc = curl_easy_init();
  struct l2_dlbuf dlbuf;
  if (!pc) return VERSION_EUNSPEC;

  l2_launcher_download_init(&dlbuf);

  if (etag) {
    size_t etaglen = strlen(etag);
    char *etagheader;

#define H_IFNONEMATCH "If-None-Match: "
    L2_ASTRCAT2(etagheader, H_IFNONEMATCH, L2_CSTRLEN(H_IFNONEMATCH), etag, etaglen);
#undef H_IFNONEMATCH

    headers = curl_slist_append(NULL, etagheader);
    if (!headers) {
      ret = VERSION_EUNSPEC;
      goto cleanup;
    }

    curl_easy_setopt(pc, CURLOPT_HTTPHEADER, headers);
  }

  curl_easy_setopt(pc, CURLOPT_URL, L2_URL_META_VERSION_MANIFEST);
  curl_easy_setopt(pc, CURLOPT_WRITEFUNCTION, l2_dlcb);
  curl_easy_setopt(pc, CURLOPT_WRITEDATA, &dlbuf);

  if (curl_easy_perform(pc) != CURLE_OK) {
    /* TODO: set error string */
    ret = VERSION_EUNSPEC;
    goto cleanup;
  }

  long rescode = 0;
  curl_easy_getinfo(pc, CURLINFO_RESPONSE_CODE, &rescode);
  if (rescode == 200) {
    char *mfpath;
    size_t datalen;
    verdata = l2_launcher_download_finalize(&dlbuf, &datalen);

    L2_ASTRCAT2(mfpath, l2_state.paths.data, pathlen, L2_VERSION_MANIFEST_PATH, L2_CSTRLEN(L2_VERSION_MANIFEST_PATH));

    outfile = fopen(mfpath, "w");
    if (!outfile) {
      ret = VERSION_ERRNO;
      goto cleanup;
    }

    if (fwrite(verdata, 1, datalen, outfile) < datalen) {
      ret = VERSION_EUNSPEC;
      goto cleanup;
    }

    fclose(outfile);
    outfile = NULL;
  }

  struct curl_header *ch;
  if (curl_easy_header(pc, "ETag", 0, CURLH_HEADER | CURLH_TRAILER | CURLH_1XX, 0, &ch) == CURLHE_OK) {
    l2_version__write_etag(etagpath, time(NULL), ch->value);
  }

  ret = VERSION_SUCCESS;

cleanup:
  en = errno;

  if (pc) curl_easy_cleanup(pc);
  if (headers) curl_slist_free_all(headers);
  if (outfile) fclose(outfile);
  free(verdata);
  l2_launcher_download_cleanup(&dlbuf);

  errno = en;
  return ret;
}
#endif

/* parses an instance of version_manifest_v2.json */
unsigned l2_version__load_all_from_json(json_t *json)
{
  if (!json_is_object(json)) {
    return VERSION_EFORMAT;
  }

  json_t *latest = json_object_get(json, "latest");
  json_t *versions = json_object_get(json, "versions");

  if (!json_is_object(latest) || !json_is_array(versions)) {
    return VERSION_EFORMAT;
  }

  const char *latestrel = json_string_value(json_object_get(latest, "release"));
  const char *latestsnap = json_string_value(json_object_get(latest, "snapshot"));
  size_t index;
  json_t *value;
  unsigned res;

  if (!latestrel || !latestsnap) {
    return VERSION_EFORMAT;
  }

  json_array_foreach(versions, index, value) {
    if ((res = l2_version__add_remote(value)) != VERSION_SUCCESS)
      return res;
  }

  return VERSION_SUCCESS;
}

unsigned l2_version__add_remote(json_t *js)
{
  struct l2_version_remote *ver = NULL;
  struct tm ts;
  json_t *val;

  unsigned res = VERSION_SUCCESS;
  
  if (!json_is_object(js)) {
    return VERSION_EFORMAT;
  }

  ver = calloc(1, sizeof(struct l2_version_remote));
  if (!ver) return VERSION_EALLOC;

  res = VERSION_EFORMAT;

  val = json_object_get(js, "id");
  if (!json_is_string(val)) goto cleanup;
  ver->id = strdup(json_string_value(val));

  val = json_object_get(js, "type");
  if (!json_is_string(val)) goto cleanup;
  ver->type = strdup(json_string_value(val));

  val = json_object_get(js, "url");
  if (!json_is_string(val)) goto cleanup;
  ver->url = strdup(json_string_value(val));

  val = json_object_get(js, "sha1");
  if (!json_is_string(val)) goto cleanup;
  if (l2_sha1_digest_from_hex(&ver->sha1, json_string_value(val)) < 0)
    goto cleanup;

  val = json_object_get(js, "complianceLevel");
  if (!json_is_number(val)) goto cleanup;
  ver->compliance_level = json_integer_value(val);

  val = json_object_get(js, "time");
  if (!json_is_string(val)) goto cleanup;
  memset(&ts, 0, sizeof(struct tm));
  if (!l2_launcher_parse_iso_time(json_string_value(val), &ts)) goto cleanup;
  ver->update_time = mktime(&ts);

  val = json_object_get(js, "releaseTime");
  if (!json_is_string(val)) goto cleanup;
  memset(&ts, 0, sizeof(struct tm));
  if (!l2_launcher_parse_iso_time(json_string_value(val), &ts)) goto cleanup;
  ver->release_time = mktime(&ts);

  /* add the thing to the global list */
  if (l2_state.ver_remote_tail) {
    l2_state.ver_remote_tail->next = ver;
    ver->prev = l2_state.ver_remote_tail;
  } else {
    l2_state.ver_remote_head = l2_state.ver_remote_tail = ver;
  }

  return VERSION_SUCCESS;

cleanup:
  if (ver) {
    free(ver->id);
    free(ver->type);
    free(ver->url);
  }

  free(ver);

  return res;
}