// Copyright 2009-present 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.

#include <algorithm>
#include <cstdint>
#include <iostream>

#include <bsoncxx/builder/basic/document.hpp>
#include <bsoncxx/builder/basic/kvp.hpp>
#include <bsoncxx/builder/stream/document.hpp>
#include <bsoncxx/builder/stream/helpers.hpp>
#include <bsoncxx/json.hpp>
#include <bsoncxx/types/bson_value/make_value.hpp>

#include <mongocxx/client.hpp>
#include <mongocxx/client_encryption.hpp>
#include <mongocxx/instance.hpp>
#include <mongocxx/options/auto_encryption.hpp>
#include <mongocxx/options/client.hpp>
#include <mongocxx/options/data_key.hpp>
#include <mongocxx/options/encrypt.hpp>

#include <examples/macros.hh>

using bsoncxx::builder::basic::kvp;
using bsoncxx::builder::basic::make_document;

using bsoncxx::builder::stream::close_document;
using bsoncxx::builder::stream::document;
using bsoncxx::builder::stream::finalize;
using bsoncxx::builder::stream::open_document;

using bsoncxx::types::bson_value::make_value;

using namespace mongocxx;

int const kKeyLength = 96;

int EXAMPLES_CDECL main() {
    instance inst{};

    // This must be the same master key that was used to create the encryption key.
    // An arbitrary key is used as a placeholder for this example.
    std::uint8_t const key_storage[kKeyLength]{
        0x45, 0xA3, 0x5B, 0xC8, 0x91, 0x76, 0x2E, 0x0F, 0x34, 0x6A, 0xD1, 0xB8, 0x55, 0x9C, 0xEA, 0x1F,
        0x88, 0x12, 0x6D, 0x3B, 0x75, 0x2A, 0xF0, 0x97, 0x41, 0xE3, 0x5C, 0xB9, 0x66, 0x0D, 0xAF, 0x52,
        0x23, 0xC4, 0x8E, 0x19, 0x74, 0xAB, 0x2F, 0xD0, 0x39, 0x6B, 0x84, 0xFC, 0x14, 0x7E, 0x93, 0x27,
        0x5D, 0x86, 0x1C, 0xA8, 0x72, 0x30, 0xB7, 0x4F, 0x09, 0xE1, 0xCA, 0x53, 0x2D, 0x94, 0xBA, 0x68,
        0x0E, 0xF5, 0x48, 0x16, 0x7F, 0xAE, 0x21, 0x6C, 0x9D, 0x82, 0x0B, 0xF2, 0x5A, 0x37, 0xCC, 0x18,
        0x4A, 0x6E, 0x95, 0xBD, 0x33, 0x57, 0xA1, 0x08, 0xDF, 0x20, 0x69, 0xE7, 0x12, 0x8B, 0xF4, 0x3D,
    };
    bsoncxx::types::b_binary local_master_key{bsoncxx::binary_sub_type::k_binary, kKeyLength, key_storage};

    auto kms_providers = document{} << "local" << open_document << "key" << local_master_key << close_document
                                    << finalize;

    // Create an unencrypted mongocxx::client.
    class client client{uri{}};
    auto coll = client["test"]["coll"];

    // Clear old data.
    coll.drop();

    // Set up the key vault for this example.
    auto key_vault = client["keyvault"]["datakeys"];

    // Ensure that two data keys cannot share the same keyAltName by adding
    // a unique index on this field.
    key_vault.drop();

    mongocxx::options::index index_options{};
    index_options.unique(true);
    auto expression = document{} << "keyAltNames" << open_document << "$exists" << true << close_document << finalize;
    index_options.partial_filter_expression(expression.view());
    key_vault.create_index(make_document(kvp("keyAltNames", 1)), index_options);

    // Set up our client_encryption
    options::client_encryption client_encryption_opts{};
    client_encryption_opts.key_vault_namespace({"keyvault", "datakeys"});
    client_encryption_opts.kms_providers(kms_providers.view());
    client_encryption_opts.key_vault_client(&client);

    class client_encryption client_encryption(std::move(client_encryption_opts));

    // Create a new data key for the encryptedField.
    auto data_key_id = client_encryption.create_data_key("local");

    // Explicitly encrypt a field:
    options::encrypt encrypt_opts{};
    encrypt_opts.key_id(data_key_id.view());
    encrypt_opts.algorithm(options::encrypt::encryption_algorithm::k_deterministic);

    auto to_encrypt = make_value("secret message");
    auto encrypted_message = client_encryption.encrypt(to_encrypt, encrypt_opts);

    coll.insert_one(make_document(kvp("encryptedField", encrypted_message)));

    // Automatically decrypts any encrypted fields.
    auto res = coll.find_one({});
    std::cout << "Explicitly encrypted document: " << bsoncxx::to_json(*res) << std::endl;

    // Explicitly decrypt the field:
    auto encrypted_message_retrieved = res->view()["encryptedField"].get_value();
    auto decrypted_message = client_encryption.decrypt(encrypted_message_retrieved);
    std::cout << "Explicitly decrypted message: " << decrypted_message.view().get_string().value << std::endl;
}