// Copyright 2015 MongoDB Inc.
//
// 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 <bsoncxx/config/prelude.hpp>

#include <bsoncxx/array/view_or_value.hpp>
#include <bsoncxx/document/view_or_value.hpp>

namespace bsoncxx {
BSONCXX_INLINE_NAMESPACE_BEGIN
namespace builder {

///
/// Container to concatenate a document. Use it by constructing an instance with the
/// document to be concatenated, and pass it into a document stream builder.
///
struct concatenate_doc {
    document::view_or_value doc;

    // MSVC seems to need a hint that it should always
    // inline this destructor.
    BSONCXX_INLINE ~concatenate_doc() = default;

    ///
    /// Conversion operator that provides a view of the wrapped concatenate
    /// document.
    ///
    /// @return A view of the wrapped concatenate document.
    ///
    BSONCXX_INLINE operator document::view() const {
        return doc;
    }

    ///
    /// Accessor that provides a view of the wrapped concatenate
    /// document.
    ///
    /// @return A view of the wrapped concatenate document.
    ///
    BSONCXX_INLINE document::view view() const {
        return doc;
    }
};

///
/// Container to concatenate an array. Use this with the array stream builder in order
/// to pass an array into a new builder and append its values to the stream.
///
struct concatenate_array {
    array::view_or_value array;

    // MSVC seems to need a hint that it should always
    // inline this destructor.
    BSONCXX_INLINE ~concatenate_array() = default;

    ///
    /// Conversion operator that provides a view of the wrapped concatenate
    /// array.
    ///
    /// @return A view of the wrapped concatenate array.
    ///
    BSONCXX_INLINE operator array::view() const {
        return array;
    }

    ///
    /// Accessor that provides a view of the wrapped concatenate
    /// array.
    ///
    /// @return A view of the wrapped concatenate array.
    ///
    BSONCXX_INLINE array::view view() const {
        return array;
    }
};

///
/// Helper method to concatenate a document. Use this with the document stream
/// builder to merge an existing document's fields with a new document's.
///
/// @param doc A document to be concatenated.
///
/// @return concatenate_doc A concatenating struct.
///
/// @relatesalso concatenate_doc
///
BSONCXX_INLINE concatenate_doc concatenate(document::view_or_value doc) {
    return {std::move(doc)};
}

///
/// Method to concatenate an array with a new array. Use this with the array stream
/// builder to merge an existing array's fields with a new array.
///
/// @param array An array to be concatenated.
///
/// @return concatenate_array A concatenating struct.
///
/// @relatesalso concatenate_array
///
BSONCXX_INLINE concatenate_array concatenate(array::view_or_value array) {
    return {std::move(array)};
}

}  // namespace builder
BSONCXX_INLINE_NAMESPACE_END
}  // namespace bsoncxx

#include <bsoncxx/config/postlude.hpp>
