/**
 *    Copyright (C) 2018-present MongoDB, Inc.
 *
 *    This program is free software: you can redistribute it and/or modify
 *    it under the terms of the Server Side Public License, version 1,
 *    as published by MongoDB, Inc.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    Server Side Public License for more details.
 *
 *    You should have received a copy of the Server Side Public License
 *    along with this program. If not, see
 *    <http://www.mongodb.com/licensing/server-side-public-license>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the Server Side Public License in all respects for
 *    all of the code used other than as permitted herein. If you modify file(s)
 *    with this exception, you may extend this exception to your version of the
 *    file(s), but you are not obligated to do so. If you do not wish to do so,
 *    delete this exception statement from your version. If you delete this
 *    exception statement from all source files in the program, then also delete
 *    it in the license file.
 */

#pragma once
#include "mongo/util/options_parser/option_description.h"

#include <boost/program_options.hpp>
#include <list>

#include "mongo/base/status.h"

namespace mongo {
namespace optionenvironment {

namespace po = boost::program_options;

/**
 *  A container for OptionDescription instances as well as other OptionSection instances.
 *  Provides a description of all options that are supported to be passed in to an
 *  OptionsParser.  Has utility functions to support the various formats needed by the parsing
 *  process
 *
 *  The sections and section names only matter in the help string.  For sections in a JSON
 *  config, look at the dots in the dottedName of the relevant OptionDescription
 *
 *  Usage:
 *
 *  namespace moe = mongo::optionenvironment;
 *
 *  moe::OptionsParser parser;
 *  moe::Environment environment;
 *  moe::OptionSection options;
 *  moe::OptionSection subSection("Section Name");
 *
 *  // Register our allowed option flags with our OptionSection
 *  options.addOptionChaining("help", "help", moe::Switch, "Display Help");
 *
 *  // Register our positional options with our OptionSection
 *  options.addOptionChaining("command", "command", moe::String, "Command").positional(1, 1);
 *
 *  // Add a subsection
 *  subSection.addOptionChaining("port", "port", moe::Int, "Port");
 *  options.addSection(subSection);
 *
 *  // Run the parser
 *  Status ret = parser.run(options, argc, argv, envp, &environment);
 *  if (!ret.isOK()) {
 *      cerr << options.helpString() << std::endl;
 *      exit(EXIT_FAILURE);
 *  }
 */

class OptionSection {
public:
    OptionSection(const std::string& name) : _name(name) {}
    OptionSection() {}

    // Construction interface

    /**
     * Add a sub section to this section.  Used mainly to keep track of section headers for when
     * we need generate the help std::string for the command line.
     *
     * Note that while the structure of this class allows for a nested hierarchy of sections,
     * our actual use-case enforces a maximum depth of 2.
     * The base node plus one level of subsections.
     * This means that subsections being added must not contain subsections of their own.
     */
    Status addSection(const OptionSection& newSection);

    /**
     * Add an option to this section, and returns a reference to an OptionDescription to allow
     * for chaining.
     *
     * Examples:
     *
     * options.addOptionChaining("option", "option", moe::String, "Chaining Registration")
     *                          .hidden().setDefault(moe::Value("default"))
     *                          .setImplicit(moe::Value("implicit"));
     *
     * This creates a hidden option that has default and implicit values.
     *
     * options.addOptionChaining("name", "name", moe::String, "Composing Option")
     *                          .composing().sources(SourceAllConfig);
     *
     * This creates an option that is composing and can be specified only in config files.
     *
     * See the OptionDescription class for details on the supported attributes.
     *
     * throws DBException on errors, such as attempting to register an option with the same name
     * as another option.  These represent programming errors that should not happen during
     * normal operation.
     */
    OptionDescription& addOptionChaining(
        const std::string& dottedName,
        const std::string& singleName,
        const OptionType type,
        const std::string& description,
        const std::vector<std::string>& deprecatedDottedNames = {},
        const std::vector<std::string>& deprecatedSingleNames = {});

    // These functions are used by the OptionsParser to make calls into boost::program_options
    Status getBoostOptions(po::options_description* boostOptions,
                           bool visibleOnly = false,
                           bool includeDefaults = false,
                           OptionSources = SourceAll,
                           bool getEmptySections = true) const;
    Status getBoostPositionalOptions(
        po::positional_options_description* boostPositionalOptions) const;

    // This is needed so that the parser can iterate over all registered options to get the
    // correct names when populating the Environment, as well as check that a parameter that was
    // found has been registered and has the correct type
    Status getAllOptions(std::vector<OptionDescription>* options) const;

    // Count the number of options in this section and all subsections
    Status countOptions(int* numOptions, bool visibleOnly, OptionSources sources) const;

    /**
     * Returns the number of subsections which have been added to this OptionSection.
     */
    size_t countSubSections() const;

    /**
     * Populates the given map with all the default values for any options in this option
     * section and all sub sections.
     */
    Status getDefaults(std::map<Key, Value>* values) const;

    /**
     * Populates the given vector with all the constraints for all options in this section and
     * sub sections.
     */
    Status getConstraints(std::vector<std::shared_ptr<Constraint>>* constraints) const;

    std::string positionalHelpString(const std::string& execName) const;
    std::string helpString() const;

    // Debugging
    void dump() const;

private:
    std::string _name;
    std::list<OptionSection> _subSections;
    std::list<OptionDescription> _options;

    /**
     * Internal accumulator of all dotted names (incl. deprecated) in _options and all _subSections.
     * Used for ensuring duplicate entries don't find their way into different parts of the tree.
     */
    std::set<std::string> _allDottedNames;

    /**
     * Internal accumulator for all single names. See _allDottedNames for further info.
     */
    std::set<std::string> _allSingleNames;
};

}  // namespace optionenvironment
}  // namespace mongo