conf.hpp

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/*
 * Copyright 2020 Robert Bosch GmbH
 *
 * 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.
 *
 * SPDX-License-Identifier: Apache-2.0
 */
#pragma once
#ifndef FABLE_CONF_HPP_
#define FABLE_CONF_HPP_

#include <functional>  // for function<>
#include <string>      // for string
#include <vector>      // for vector<>

#include <fmt/format.h>  // for fmt::format

#include <fable/json.hpp>  // for Json

// Forward declaration:
namespace boost {
namespace filesystem {
class path;
}  // namespace filesystem
}  // namespace boost

namespace fable {

class ConfError;

class Conf {
 public:
  Conf() = default;
  explicit Conf(const Json& data) : data_(data) {}
  explicit Conf(const std::string& file);
  Conf(const Json& data, const std::string& file) : file_(file), data_(data) {}
  Conf(const Json& data, const std::string& file, const std::string& root)
      : file_(file), root_(root), data_(data) {}

  bool is_from_file() const { return !file_.empty(); }

  const std::string& file() const { return file_; }

  bool is_empty() const { return data_.is_null(); }

  const Json& operator*() const { return data_; }
  Json& operator*() { return data_; }

  const Json* operator->() const { return &data_; }
  Json* operator->() { return &data_; }

  std::string root() const { return (root_.empty() ? "/" : root_); }

  bool has(const std::string& key) const { return data_.count(key) != 0; }
  bool has(const JsonPointer& key) const;
  bool has_pointer(const std::string& key) const { return has(JsonPointer(key)); }

  Conf at(const std::string& key) const;
  Conf at(const JsonPointer& key) const;
  Conf at_pointer(const std::string& key) const { return at(JsonPointer(key)); }

  size_t erase(const std::string& key);
  size_t erase(const JsonPointer& key);
  size_t erase_pointer(const std::string& key) { return erase(JsonPointer(key)); }

  std::vector<Conf> to_array() const;

  template <typename T>
  T get() const {
    try {
      return data_.get<T>();
    } catch (nlohmann::detail::type_error&) {
      throw_wrong_type();
    }
  }

  template <typename T>
  T get(const std::string& key) const {
    try {
      return data_.at(key).get<T>();
    } catch (nlohmann::detail::out_of_range&) {
      throw_missing(key);
    } catch (nlohmann::detail::type_error&) {
      throw_wrong_type(key);
    }
  }

  template <typename T>
  T get(const JsonPointer& key) const {
    try {
      return data_.at(key).get<T>();
    } catch (nlohmann::detail::out_of_range&) {
      throw_missing(key);
    } catch (nlohmann::detail::type_error&) {
      throw_wrong_type(key);
    }
  }

  template <typename T>
  T get_pointer(const std::string& key) const {
    return get<T>(JsonPointer(key));
  }

  template <typename T>
  T get_or(const std::string& key, T def) const {
    if (!data_.count(key)) {
      return def;
    }
    try {
      return data_.at(key).get<T>();
    } catch (nlohmann::detail::type_error&) {
      throw_wrong_type(key);
    }
  }

  template <typename T>
  T get_or(const JsonPointer& key, T def) const {
    try {
      return data_.at(key).get<T>();
    } catch (nlohmann::detail::out_of_range&) {
      return def;
    } catch (nlohmann::detail::type_error&) {
      throw_wrong_type(key);
    }
  }

  template <typename T>
  T get_pointer_or(const std::string& key, T def) const {
    return get_or(key, def);
  }

  template <typename T>
  void with(const std::string& key, std::function<void(const T&)> fn) const {
    if (data_.count(key)) {
      fn(get<T>(key));
    }
  }

  template <typename T>
  void with(const JsonPointer& key, std::function<void(const T&)> fn) const {
    try {
      fn(get<T>(key));
    } catch (nlohmann::detail::out_of_range&) {
      return;
    }
  }

  template <typename T>
  void with_pointer(const std::string& key, std::function<void(const T&)> fn) const {
    with(JsonPointer(key), fn);
  }

  template <typename T>
  void try_from(const std::string& key, T* val) const {
    if (data_.count(key)) {
      *val = get<T>(key);
    }
  }

  template <typename T>
  void try_from(const JsonPointer& key, T* val) const {
    try {
      *val = data_.at(key).get<T>();
    } catch (nlohmann::detail::out_of_range& e) {
      return;
    } catch (nlohmann::detail::type_error& e) {
      throw_wrong_type(key);
    }
  }

  template <typename T>
  void try_from_pointer(const std::string& key, T* val) const {
    try_from(JsonPointer(key), val);
  }

  void assert_has(const std::string& key) const;
  void assert_has(const JsonPointer& key) const;
  void assert_has_pointer(const std::string& key) const { assert_has(JsonPointer(key)); }

  void assert_has_type(const std::string& key, JsonType t) const;
  void assert_has_type(const JsonPointer& key, JsonType t) const;
  void assert_has_pointer_type(const std::string& key, JsonType t) const {
    assert_has_type(JsonPointer(key), t);
  }

  void assert_has_not(const std::string& key, const std::string& msg = "") const;
  void assert_has_not(const JsonPointer& key, const std::string& msg = "") const;
  void assert_has_pointer_not(const std::string& key, const std::string& msg = "") const {
    assert_has_not(JsonPointer(key), msg);
  }

  boost::filesystem::path resolve_file(const boost::filesystem::path& filename) const;
  std::string resolve_file(const std::string& filename) const;

  template <typename... Args>
  [[noreturn]] void throw_error(const char* msg, const Args&... args) const {
    throw_error(fmt::format(msg, args...));
  }
  [[noreturn]] void throw_error(const std::string& msg) const;
  [[noreturn]] void throw_unexpected(const std::string& key, const std::string& msg = "") const;
  [[noreturn]] void throw_missing(const std::string& key) const;
  [[noreturn]] void throw_wrong_type(const std::string& key = "") const;
  [[noreturn]] void throw_wrong_type(const std::string& key, JsonType type) const;

  friend void to_json(Json& j, const Conf& c) { j = *c; }
  friend void from_json(const Json& j, Conf& c) { *c = j; }

 private:
  std::string file_;
  std::string root_;
  Json data_;
};

}  // namespace fable

#endif  // FABLE_CONF_HPP_