/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

/*
 * Modified by ScyllaDB
 *
 * Copyright (C) 2015 ScyllaDB
 */

/*
 * This file is part of Scylla.
 *
 * Scylla is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * Scylla 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
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Scylla.  If not, see <http://www.gnu.org/licenses/>.
 */

#pragma once

#include "castas_fcts.hh"
#include "native_scalar_function.hh"
#include "utils/UUID_gen.hh"
#include <boost/uuid/uuid.hpp>
#include <boost/uuid/uuid_generators.hpp>

namespace cql3 {

namespace functions {

namespace time_uuid_fcts {

inline
shared_ptr<function>
make_now_fct() {
    return make_native_scalar_function<false>("now", timeuuid_type, {},
            [] (cql_serialization_format sf, const std::vector<bytes_opt>& values) -> bytes_opt {
        return {to_bytes(utils::UUID_gen::get_time_UUID())};
    });
}

inline
shared_ptr<function>
make_min_timeuuid_fct() {
    return make_native_scalar_function<true>("mintimeuuid", timeuuid_type, { timestamp_type },
            [] (cql_serialization_format sf, const std::vector<bytes_opt>& values) -> bytes_opt {
        auto& bb = values[0];
        if (!bb) {
            return {};
        }
        auto ts_obj = timestamp_type->deserialize(*bb);
        if (ts_obj.is_null()) {
            return {};
        }
        auto ts = value_cast<db_clock::time_point>(ts_obj);
        auto uuid = utils::UUID_gen::min_time_UUID(ts.time_since_epoch().count());
        return {timeuuid_type->decompose(uuid)};
    });
}

inline
shared_ptr<function>
make_max_timeuuid_fct() {
    return make_native_scalar_function<true>("maxtimeuuid", timeuuid_type, { timestamp_type },
            [] (cql_serialization_format sf, const std::vector<bytes_opt>& values) -> bytes_opt {
        // FIXME: should values be a vector<optional<bytes>>?
        auto& bb = values[0];
        if (!bb) {
            return {};
        }
        auto ts_obj = timestamp_type->deserialize(*bb);
        if (ts_obj.is_null()) {
            return {};
        }
        auto ts = value_cast<db_clock::time_point>(ts_obj);
        auto uuid = utils::UUID_gen::max_time_UUID(ts.time_since_epoch().count());
        return {timeuuid_type->decompose(uuid)};
    });
}

inline
shared_ptr<function>
make_date_of_fct() {
    return make_native_scalar_function<true>("dateof", timestamp_type, { timeuuid_type },
            [] (cql_serialization_format sf, const std::vector<bytes_opt>& values) -> bytes_opt {
        using namespace utils;
        auto& bb = values[0];
        if (!bb) {
            return {};
        }
        auto ts = db_clock::time_point(db_clock::duration(UUID_gen::unix_timestamp(UUID_gen::get_UUID(*bb))));
        return {timestamp_type->decompose(ts)};
    });
}

inline
shared_ptr<function>
make_unix_timestamp_of_fct() {
    return make_native_scalar_function<true>("unixtimestampof", long_type, { timeuuid_type },
            [] (cql_serialization_format sf, const std::vector<bytes_opt>& values) -> bytes_opt {
        using namespace utils;
        auto& bb = values[0];
        if (!bb) {
            return {};
        }
        return {long_type->decompose(UUID_gen::unix_timestamp(UUID_gen::get_UUID(*bb)))};
    });
}

inline shared_ptr<function>
make_currenttimestamp_fct() {
    return make_native_scalar_function<true>("currenttimestamp", timestamp_type, {},
            [] (cql_serialization_format sf, const std::vector<bytes_opt>& values) -> bytes_opt {
        return {timestamp_type->decompose(db_clock::now())};
    });
}

inline shared_ptr<function>
make_currenttime_fct() {
    return make_native_scalar_function<true>("currenttime", time_type, {},
            [] (cql_serialization_format sf, const std::vector<bytes_opt>& values) -> bytes_opt {
        constexpr int64_t milliseconds_in_day = 3600 * 24 * 1000;
        int64_t milliseconds_since_epoch = std::chrono::duration_cast<std::chrono::milliseconds>(db_clock::now().time_since_epoch()).count();
        int64_t nanoseconds_today = (milliseconds_since_epoch % milliseconds_in_day) * 1000 * 1000;
        return {time_type->decompose(time_native_type{nanoseconds_today})};
    });
}

inline shared_ptr<function>
make_currentdate_fct() {
    return make_native_scalar_function<true>("currentdate", simple_date_type, {},
            [] (cql_serialization_format sf, const std::vector<bytes_opt>& values) -> bytes_opt {
        auto to_simple_date = get_castas_fctn(simple_date_type, timestamp_type);
        return {simple_date_type->decompose(to_simple_date(db_clock::now()))};
    });
}

inline
shared_ptr<function>
make_currenttimeuuid_fct() {
    return make_native_scalar_function<true>("currenttimeuuid", timeuuid_type, {},
            [] (cql_serialization_format sf, const std::vector<bytes_opt>& values) -> bytes_opt {
        return {timeuuid_type->decompose(timeuuid_native_type{utils::UUID_gen::get_time_UUID()})};
    });
}

inline
shared_ptr<function>
make_timeuuidtodate_fct() {
    return make_native_scalar_function<true>("todate", simple_date_type, { timeuuid_type },
            [] (cql_serialization_format sf, const std::vector<bytes_opt>& values) -> bytes_opt {
        using namespace utils;
        auto& bb = values[0];
        if (!bb) {
            return {};
        }
        auto ts = db_clock::time_point(db_clock::duration(UUID_gen::unix_timestamp(UUID_gen::get_UUID(*bb))));
        auto to_simple_date = get_castas_fctn(simple_date_type, timestamp_type);
        return {simple_date_type->decompose(to_simple_date(ts))};
    });
}

inline
shared_ptr<function>
make_timestamptodate_fct() {
    return make_native_scalar_function<true>("todate", simple_date_type, { timestamp_type },
            [] (cql_serialization_format sf, const std::vector<bytes_opt>& values) -> bytes_opt {
        using namespace utils;
        auto& bb = values[0];
        if (!bb) {
            return {};
        }
        auto ts_obj = timestamp_type->deserialize(*bb);
        if (ts_obj.is_null()) {
            return {};
        }
        auto to_simple_date = get_castas_fctn(simple_date_type, timestamp_type);
        return {simple_date_type->decompose(to_simple_date(ts_obj))};
    });
}

inline
shared_ptr<function>
make_timeuuidtotimestamp_fct() {
    return make_native_scalar_function<true>("totimestamp", timestamp_type, { timeuuid_type },
            [] (cql_serialization_format sf, const std::vector<bytes_opt>& values) -> bytes_opt {
        using namespace utils;
        auto& bb = values[0];
        if (!bb) {
            return {};
        }
        auto ts = db_clock::time_point(db_clock::duration(UUID_gen::unix_timestamp(UUID_gen::get_UUID(*bb))));
        return {timestamp_type->decompose(ts)};
    });
}

inline
shared_ptr<function>
make_datetotimestamp_fct() {
    return make_native_scalar_function<true>("totimestamp", timestamp_type, { simple_date_type },
            [] (cql_serialization_format sf, const std::vector<bytes_opt>& values) -> bytes_opt {
        using namespace utils;
        auto& bb = values[0];
        if (!bb) {
            return {};
        }
        auto simple_date_obj = simple_date_type->deserialize(*bb);
        if (simple_date_obj.is_null()) {
            return {};
        }
        auto from_simple_date = get_castas_fctn(timestamp_type, simple_date_type);
        return {timestamp_type->decompose(from_simple_date(simple_date_obj))};
    });
}

inline
shared_ptr<function>
make_timeuuidtounixtimestamp_fct() {
    return make_native_scalar_function<true>("tounixtimestamp", long_type, { timeuuid_type },
            [] (cql_serialization_format sf, const std::vector<bytes_opt>& values) -> bytes_opt {
        using namespace utils;
        auto& bb = values[0];
        if (!bb) {
            return {};
        }
        return {long_type->decompose(UUID_gen::unix_timestamp(UUID_gen::get_UUID(*bb)))};
    });
}

inline bytes time_point_to_long(const data_value& v) {
    auto since_epoch = value_cast<db_clock::time_point>(v).time_since_epoch();
    int64_t ms = std::chrono::duration_cast<std::chrono::milliseconds>(since_epoch).count();
    return serialized(ms);
}

inline
shared_ptr<function>
make_timestamptounixtimestamp_fct() {
    return make_native_scalar_function<true>("tounixtimestamp", long_type, { timestamp_type },
            [] (cql_serialization_format sf, const std::vector<bytes_opt>& values) -> bytes_opt {
        using namespace utils;
        auto& bb = values[0];
        if (!bb) {
            return {};
        }
        auto ts_obj = timestamp_type->deserialize(*bb);
        if (ts_obj.is_null()) {
            return {};
        }
        return time_point_to_long(ts_obj);
    });
}

inline
shared_ptr<function>
make_datetounixtimestamp_fct() {
    return make_native_scalar_function<true>("tounixtimestamp", long_type, { simple_date_type },
            [] (cql_serialization_format sf, const std::vector<bytes_opt>& values) -> bytes_opt {
        using namespace utils;
        auto& bb = values[0];
        if (!bb) {
            return {};
        }
        auto simple_date_obj = simple_date_type->deserialize(*bb);
        if (simple_date_obj.is_null()) {
            return {};
        }
        auto from_simple_date = get_castas_fctn(timestamp_type, simple_date_type);
        return time_point_to_long(from_simple_date(simple_date_obj));
    });
}

}
}
}
