/*
// Copyright (c) 2018 Intel Corporation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
*/
#pragma once

#include "error_messages.hpp"
#include "node.hpp"
#include "persistent_data_middleware.hpp"

namespace redfish {

class SessionCollection;

class Sessions : public Node {
 public:
  Sessions(CrowApp& app)
      : Node(app, "/redfish/v1/SessionService/Sessions/<str>/", std::string()) {
    Node::json["@odata.type"] = "#Session.v1_0_2.Session";
    Node::json["@odata.context"] = "/redfish/v1/$metadata#Session.Session";
    Node::json["Name"] = "User Session";
    Node::json["Description"] = "Manager User Session";

    entityPrivileges = {
        {boost::beast::http::verb::get, {{"Login"}}},
        {boost::beast::http::verb::head, {{"Login"}}},
        {boost::beast::http::verb::patch, {{"ConfigureManager"}}},
        {boost::beast::http::verb::put, {{"ConfigureManager"}}},
        {boost::beast::http::verb::delete_, {{"ConfigureManager"}}},
        {boost::beast::http::verb::post, {{"ConfigureManager"}}}};
  }

 private:
  void doGet(crow::response& res, const crow::request& req,
             const std::vector<std::string>& params) override {
    auto session =
        crow::PersistentData::SessionStore::getInstance().get_session_by_uid(
            params[0]);

    if (session == nullptr) {
      messages::addMessageToErrorJson(
          res.json_value, messages::resourceNotFound("Session", params[0]));

      res.result(boost::beast::http::status::not_found);
      res.end();
      return;
    }

    Node::json["Id"] = session->unique_id;
    Node::json["UserName"] = session->username;
    Node::json["@odata.id"] =
        "/redfish/v1/SessionService/Sessions/" + session->unique_id;

    res.json_value = Node::json;
    res.end();
  }

  void doDelete(crow::response& res, const crow::request& req,
                const std::vector<std::string>& params) override {
    // Need only 1 param which should be id of session to be deleted
    if (params.size() != 1) {
      // This should be handled by crow and never happen
      CROW_LOG_ERROR
          << "Session DELETE has been called with invalid number of params";

      res.result(boost::beast::http::status::bad_request);
      messages::addMessageToErrorJson(res.json_value, messages::generalError());

      res.end();
      return;
    }

    auto session =
        crow::PersistentData::SessionStore::getInstance().get_session_by_uid(
            params[0]);

    if (session == nullptr) {
      messages::addMessageToErrorJson(
          res.json_value, messages::resourceNotFound("Session", params[0]));

      res.result(boost::beast::http::status::not_found);
      res.end();
      return;
    }

    // DELETE should return representation of object that will be removed
    doGet(res, req, params);

    crow::PersistentData::SessionStore::getInstance().remove_session(session);
  }

  /**
   * This allows SessionCollection to reuse this class' doGet method, to
   * maintain consistency of returned data, as Collection's doPost should return
   * data for created member which should match member's doGet result in 100%
   */
  friend SessionCollection;
};

class SessionCollection : public Node {
 public:
  SessionCollection(CrowApp& app)
      : Node(app, "/redfish/v1/SessionService/Sessions/"), memberSession(app) {
    Node::json["@odata.type"] = "#SessionCollection.SessionCollection";
    Node::json["@odata.id"] = "/redfish/v1/SessionService/Sessions/";
    Node::json["@odata.context"] =
        "/redfish/v1/$metadata#SessionCollection.SessionCollection";
    Node::json["Name"] = "Session Collection";
    Node::json["Description"] = "Session Collection";
    Node::json["Members@odata.count"] = 0;
    Node::json["Members"] = nlohmann::json::array();

    entityPrivileges = {
        {boost::beast::http::verb::get, {{"Login"}}},
        {boost::beast::http::verb::head, {{"Login"}}},
        {boost::beast::http::verb::patch, {{"ConfigureManager"}}},
        {boost::beast::http::verb::put, {{"ConfigureManager"}}},
        {boost::beast::http::verb::delete_, {{"ConfigureManager"}}},
        {boost::beast::http::verb::post, {}}};
  }

 private:
  void doGet(crow::response& res, const crow::request& req,
             const std::vector<std::string>& params) override {
    std::vector<const std::string*> session_ids =
        crow::PersistentData::SessionStore::getInstance().get_unique_ids(
            false, crow::PersistentData::PersistenceType::TIMEOUT);

    Node::json["Members@odata.count"] = session_ids.size();
    Node::json["Members"] = nlohmann::json::array();
    for (const std::string* uid : session_ids) {
      Node::json["Members"].push_back(
          {{"@odata.id", "/redfish/v1/SessionService/Sessions/" + *uid}});
    }

    res.json_value = Node::json;
    res.end();
  }

  void doPost(crow::response& res, const crow::request& req,
              const std::vector<std::string>& params) override {
    boost::beast::http::status status;
    std::string username;
    bool userAuthSuccessful =
        authenticateUser(req, status, username, res.json_value);
    res.result(status);

    if (!userAuthSuccessful) {
      res.end();
      return;
    }

    // User is authenticated - create session for him
    auto session =
        crow::PersistentData::SessionStore::getInstance().generate_user_session(
            username);
    res.add_header("X-Auth-Token", session->session_token);

    // Return data for created session
    memberSession.doGet(res, req, {session->unique_id});

    // No need for res.end(), as it is called by doGet()
  }

  /**
   * @brief Verifies data provided in request and tries to authenticate user
   *
   * @param[in]  req            Crow request containing authentication data
   * @param[out] httpRespCode   HTTP Code that should be returned in response
   * @param[out] user           Retrieved username - not filled on failure
   * @param[out] errJson        JSON to which error messages will be written
   *
   * @return true if authentication was successful, false otherwise
   */
  bool authenticateUser(const crow::request& req,
                        boost::beast::http::status& httpRespCode,
                        std::string& user, nlohmann::json& errJson) {
    // We need only UserName and Password - nothing more, nothing less
    static constexpr const unsigned int numberOfRequiredFieldsInReq = 2;

    // call with exceptions disabled
    auto login_credentials = nlohmann::json::parse(req.body, nullptr, false);
    if (login_credentials.is_discarded()) {
      httpRespCode = boost::beast::http::status::bad_request;

      messages::addMessageToErrorJson(errJson, messages::malformedJSON());

      return false;
    }

    // Check that there are only as many fields as there should be
    if (login_credentials.size() != numberOfRequiredFieldsInReq) {
      httpRespCode = boost::beast::http::status::bad_request;

      messages::addMessageToErrorJson(errJson, messages::malformedJSON());

      return false;
    }

    // Find fields that we need - UserName and Password
    auto user_it = login_credentials.find("UserName");
    auto pass_it = login_credentials.find("Password");
    if (user_it == login_credentials.end() ||
        pass_it == login_credentials.end()) {
      httpRespCode = boost::beast::http::status::bad_request;

      if (user_it == login_credentials.end()) {
        messages::addMessageToErrorJson(errJson,
                                        messages::propertyMissing("UserName"));
      }

      if (pass_it == login_credentials.end()) {
        messages::addMessageToErrorJson(errJson,
                                        messages::propertyMissing("Password"));
      }

      return false;
    }

    // Check that given data is of valid type (string)
    if (!user_it->is_string() || !pass_it->is_string()) {
      httpRespCode = boost::beast::http::status::bad_request;

      if (!user_it->is_string()) {
        messages::addMessageToErrorJson(
            errJson,
            messages::propertyValueTypeError(user_it->dump(), "UserName"));
      }

      if (!pass_it->is_string()) {
        messages::addMessageToErrorJson(
            errJson,
            messages::propertyValueTypeError(user_it->dump(), "Password"));
      }

      return false;
    }

    // Extract username and password
    std::string username = user_it->get<const std::string>();
    std::string password = pass_it->get<const std::string>();

    // Verify that required fields are not empty
    if (username.empty() || password.empty()) {
      httpRespCode = boost::beast::http::status::bad_request;

      if (username.empty()) {
        messages::addMessageToErrorJson(errJson,
                                        messages::propertyMissing("UserName"));
      }

      if (password.empty()) {
        messages::addMessageToErrorJson(errJson,
                                        messages::propertyMissing("Password"));
      }

      return false;
    }

    // Finally - try to authenticate user
    if (!pam_authenticate_user(username, password)) {
      httpRespCode = boost::beast::http::status::unauthorized;

      messages::addMessageToErrorJson(
          errJson, messages::resourceAtUriUnauthorized(
                       std::string(req.url), "Invalid username or password"));

      return false;
    }

    // User authenticated successfully
    httpRespCode = boost::beast::http::status::ok;
    user = username;

    return true;
  }

  /**
   * Member session to ensure consistency between collection's doPost and
   * member's doGet, as they should return 100% matching data
   */
  Sessions memberSession;
};

class SessionService : public Node {
 public:
  SessionService(CrowApp& app) : Node(app, "/redfish/v1/SessionService/") {
    Node::json["@odata.type"] = "#SessionService.v1_0_2.SessionService";
    Node::json["@odata.id"] = "/redfish/v1/SessionService/";
    Node::json["@odata.context"] =
        "/redfish/v1/$metadata#SessionService.SessionService";
    Node::json["Name"] = "Session Service";
    Node::json["Id"] = "SessionService";
    Node::json["Description"] = "Session Service";
    Node::json["SessionTimeout"] =
        crow::PersistentData::SessionStore::getInstance()
            .get_timeout_in_seconds();
    Node::json["ServiceEnabled"] = true;

    entityPrivileges = {
        {boost::beast::http::verb::get, {{"Login"}}},
        {boost::beast::http::verb::head, {{"Login"}}},
        {boost::beast::http::verb::patch, {{"ConfigureManager"}}},
        {boost::beast::http::verb::put, {{"ConfigureManager"}}},
        {boost::beast::http::verb::delete_, {{"ConfigureManager"}}},
        {boost::beast::http::verb::post, {{"ConfigureManager"}}}};
  }

 private:
  void doGet(crow::response& res, const crow::request& req,
             const std::vector<std::string>& params) override {
    res.json_value = Node::json;
    res.end();
  }
};

}  // namespace redfish