/**
 *    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 <map>
#include <vector>

#include "mongo/base/status.h"
#include "mongo/bson/util/builder.h"

namespace mongo {
namespace optionenvironment {

class Constraint;
class KeyConstraint;

/**
 * Helper typedefs for the more complex C++ types supported by this Value class
 */
typedef std::map<std::string, std::string> StringMap_t;
typedef std::vector<std::string> StringVector_t;

typedef std::string Key;

/** A simple container interface for storing various C++ values.
 *
 *  Usage:
 *
 *  Value intVal(2);
 *  Value stringVal("string");
 *
 *  int intContents = 1;
 *  Status ret = stringVal.get(&intContents);
 *  // ret != Status::OK()
 *  // intContents is still 1
 *
 *  ret = intVal.get(&intContents);
 *  // ret == Status::OK()
 *  // intContents is now 2
 */
class Value {
public:
    // Constructors

    explicit Value() : _type(None) {}
    explicit Value(StringVector_t val) : _stringVectorVal(val), _type(StringVector) {}
    explicit Value(StringMap_t val) : _stringMapVal(val), _type(StringMap) {}
    explicit Value(bool val) : _boolVal(val), _type(Bool) {}
    explicit Value(double val) : _doubleVal(val), _type(Double) {}
    explicit Value(int val) : _intVal(val), _type(Int) {}
    explicit Value(long val) : _longVal(val), _type(Long) {}
    explicit Value(std::string val) : _stringVal(val), _type(String) {}
    explicit Value(const char* val) : _stringVal(val), _type(String) {}
    explicit Value(unsigned long long val) : _unsignedLongLongVal(val), _type(UnsignedLongLong) {}
    explicit Value(unsigned val) : _unsignedVal(val), _type(Unsigned) {}

    // Access interface

    Status get(StringVector_t* val) const;
    Status get(StringMap_t* val) const;
    Status get(bool* val) const;
    Status get(double* val) const;
    Status get(int* val) const;
    Status get(long* val) const;
    Status get(std::string* val) const;
    Status get(unsigned long long* val) const;
    Status get(unsigned* val) const;

    // Utility functions

    /**
     *  Return the value's type as a string
     */
    std::string typeToString() const;

    /**
     *  Return true if the value was created with the no argument constructor
     */
    bool isEmpty() const;

    /**
     *  Return true if the other Value equals this value, both in type and in contents
     *
     *  Two empty values are equal
     */
    bool equal(const Value&) const;

    /**
     *  Return the std::string representation of this Value.  This function is used only for
     *  debugging purposes and does not output data in an easily parseable format.
     */
    std::string toString() const;

    /**
     *  The functions below are the legacy interface to be consistent with boost::any during the
     *  transition period
     */

    /**
     *  Returns the contents of this Value as type T.  Throws AssertionException if the type
     *  does not match
     */
    template <typename T>
    T as() const;

    /**
     *  Return the type_info for this value
     */
    const std::type_info& type() const;

private:
    StringVector_t _stringVectorVal;
    StringMap_t _stringMapVal;
    std::string _stringVal;
    union {
        bool _boolVal;
        double _doubleVal;
        int _intVal;
        long _longVal;
        unsigned long long _unsignedLongLongVal;
        unsigned _unsignedVal;
    };

    // Types currently supported by Value
    enum Type {
        StringVector,      // std::vector<std::string>
        StringMap,         // std::map<std::string, std::string>
        Bool,              // bool
        Double,            // double
        Int,               // int
        Long,              // long
        String,            // std::string
        UnsignedLongLong,  // unsigned long long
        Unsigned,          // unsigned
        None,              // (not set)
    };

    Type _type;
};

template <typename T>
T Value::as() const {
    T valueType;

    Status ret = get(&valueType);
    if (!ret.isOK()) {
        StringBuilder message;
        message << "failed to extract typed value from Value container: " << ret.toString();
        uasserted(17114, message.str());
    }

    return valueType;
}

}  // namespace optionenvironment
}  // namespace mongo