#include "subscription_backend_impl.hpp"

#include <memory>
#include <string>
#include <system_error>  // NOLINT
#include <unordered_set>
#include <utility>
#include <vector>

#include "absl/log/die_if_null.h"
#include "absl/memory/memory.h"
#include "absl/status/status.h"
#include "absl/status/statusor.h"
#include "absl/strings/string_view.h"
#include "boost/beast/http/message.hpp"  //NOLINT
#include "boost/beast/http/string_body.hpp"  //NOLINT
#include "boost/beast/http/verb.hpp"  // NOLINT
#include "subscription.h"
#include "g3/macros.h"
#include "nlohmann/json.hpp"
#include "app.hpp"

namespace milotic {

namespace {

// Create Internal Request to query given `url`.
absl::StatusOr<crow::Request> CreateInternalRedfishRequest(
    absl::string_view url, boost::beast::http::verb method,
    const std::unordered_set<std::string>& peer_privileges) {
  boost::beast::http::request<boost::beast::http::string_body> boost_request;
  boost_request.target(url);
  boost_request.method(method);
  std::error_code error;
  crow::Request crow_request(boost_request, error);
  if (error) {
    return absl::InternalError("Error creating crow_request.");
  }

  crow_request.fromGrpc = true;
  // At this moment, peer is authenticated for sure and BMC must have trust
  // bundle. These have been checked in the Subscription RPC handler.
  crow_request.peer_authenticated = true;
  crow_request.with_trust_bundle = true;
  crow_request.peer_privileges = peer_privileges;
  return crow_request;
}

}  // namespace

std::unique_ptr<BmcWebBackend> BmcWebBackend::Create(App* app) {
  return absl::WrapUnique(new BmcWebBackend(*ABSL_DIE_IF_NULL(app)));
}

absl::Status BmcWebBackend::Query(
    absl::string_view url, QueryCallback&& query_callback,
    const std::unordered_set<std::string>& peer_privileges) {
  // Strand is not needed for subscriptions.
  auto async_resp = std::make_shared<bmcweb::AsyncResp>(nullptr);
  async_resp->response_type =
      bmcweb::AsyncResp::ResponseType::kOriginOfCondition;
  ECCLESIA_ASSIGN_OR_RETURN(
      crow::Request crow_request,
      CreateInternalRedfishRequest(url, boost::beast::http::verb::get,
                                   peer_privileges));
  async_resp->res.setCompleteRequestHandler(
      [query_callback(std::move(query_callback))](crow::Response& res) {
        if (!res.stringResponse) {
          query_callback(absl::InternalError("HTTP response is empty!"), {});
          return;
        }
        query_callback(absl::OkStatus(), res.jsonValue);
      });

  app_.handle(crow_request, async_resp);
  return absl::OkStatus();
}

absl::Status BmcWebBackend::Subscribe(
    absl::string_view url, SubscribeCallback&& callback,
    const std::unordered_set<std::string>& peer_privileges) {
  // Strand is not needed for subscriptions.
  auto async_resp = std::make_shared<bmcweb::AsyncResp>(nullptr);
  async_resp->response_type = bmcweb::AsyncResp::ResponseType::kSubscription;
  ECCLESIA_ASSIGN_OR_RETURN(
      crow::Request crow_request,
      CreateInternalRedfishRequest(url, boost::beast::http::verb::get,
                                   peer_privileges));
  async_resp->res.setCompleteRequestHandler(
      [subscribe_callback(std::move(callback))](crow::Response& res) {
        if (res.eventSourceIds.empty()) {
          subscribe_callback(
              absl::InternalError("EventSourceIds are not populated!"), {});
          return;
        }
        subscribe_callback(absl::OkStatus(), res.eventSourceIds);
      });
  app_.handle(crow_request, async_resp);
  return absl::OkStatus();
}

}  // namespace milotic