/*
 * This file is open source software, licensed to you under the terms
 * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
 * distributed with this work for additional information regarding copyright
 * ownership.  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.
 */
/*
 * Copyright (C) 2014 Cloudius Systems, Ltd.
 */

#include <seastar/core/app-template.hh>
#include <seastar/core/shared_ptr.hh>
#include <seastar/core/reactor.hh>
#include <seastar/core/vector-data-sink.hh>
#include <seastar/core/future-util.hh>
#include <seastar/core/sstring.hh>
#include <seastar/net/packet.hh>
#include <seastar/testing/test_case.hh>
#include <vector>

using namespace seastar;
using namespace net;

static sstring to_sstring(const packet& p) {
    sstring res(sstring::initialized_later(), p.len());
    auto i = res.begin();
    for (auto& frag : p.fragments()) {
        i = std::copy(frag.base, frag.base + frag.size, i);
    }
    return res;
}

struct stream_maker {
    bool _trim = false;
    size_t _size;

    stream_maker size(size_t size) && {
        _size = size;
        return std::move(*this);
    }

    stream_maker trim(bool do_trim) && {
        _trim = do_trim;
        return std::move(*this);
    }

    lw_shared_ptr<output_stream<char>> operator()(data_sink sink) {
        return make_lw_shared<output_stream<char>>(std::move(sink), _size, _trim);
    }
};

template <typename T, typename StreamConstructor>
future<> assert_split(StreamConstructor stream_maker, std::initializer_list<T> write_calls,
        std::vector<std::string> expected_split) {
    static int i = 0;
    BOOST_TEST_MESSAGE("checking split: " << i++);
    auto sh_write_calls = make_lw_shared<std::initializer_list<T>>(std::move(write_calls));
    auto sh_expected_splits = make_lw_shared<std::vector<std::string>>(std::move(expected_split));
    auto v = make_shared<std::vector<packet>>();
    auto out = stream_maker(data_sink(std::make_unique<vector_data_sink>(*v)));

    return do_for_each(sh_write_calls->begin(), sh_write_calls->end(), [out, sh_write_calls] (auto&& chunk) {
        return out->write(chunk);
    }).then([out, v, sh_expected_splits] {
        return out->close().then([out, v, sh_expected_splits] {
            BOOST_REQUIRE_EQUAL(v->size(), sh_expected_splits->size());
            int i = 0;
            for (auto&& chunk : *sh_expected_splits) {
                BOOST_REQUIRE(to_sstring((*v)[i]) == chunk);
                i++;
            }
        });
    });
}

SEASTAR_TEST_CASE(test_splitting) {
    auto ctor = stream_maker().trim(false).size(4);
    return now()
        .then([=] { return assert_split(ctor, {"1"}, {"1"}); })
        .then([=] { return assert_split(ctor, {"12", "3"}, {"123"}); })
        .then([=] { return assert_split(ctor, {"12", "34"}, {"1234"}); })
        .then([=] { return assert_split(ctor, {"12", "345"}, {"1234", "5"}); })
        .then([=] { return assert_split(ctor, {"1234"}, {"1234"}); })
        .then([=] { return assert_split(ctor, {"12345"}, {"12345"}); })
        .then([=] { return assert_split(ctor, {"1234567890"}, {"1234567890"}); })
        .then([=] { return assert_split(ctor, {"1", "23456"}, {"1234", "56"}); })
        .then([=] { return assert_split(ctor, {"123", "4567"}, {"1234", "567"}); })
        .then([=] { return assert_split(ctor, {"123", "45678"}, {"1234", "5678"}); })
        .then([=] { return assert_split(ctor, {"123", "4567890"}, {"1234", "567890"}); })
        .then([=] { return assert_split(ctor, {"1234", "567"}, {"1234", "567"}); })

        .then([] { return assert_split(stream_maker().trim(false).size(3), {"1", "234567", "89"}, {"123", "4567", "89"}); })
        .then([] { return assert_split(stream_maker().trim(false).size(3), {"1", "2345", "67"}, {"123", "456", "7"}); })
        ;
}

SEASTAR_TEST_CASE(test_splitting_with_trimming) {
    auto ctor = stream_maker().trim(true).size(4);
    return now()
        .then([=] { return assert_split(ctor, {"1"}, {"1"}); })
        .then([=] { return assert_split(ctor, {"12", "3"}, {"123"}); })
        .then([=] { return assert_split(ctor, {"12", "3456789"}, {"1234", "5678", "9"}); })
        .then([=] { return assert_split(ctor, {"12", "3456789", "12"}, {"1234", "5678", "912"}); })
        .then([=] { return assert_split(ctor, {"123456789"}, {"1234", "5678", "9"}); })
        .then([=] { return assert_split(ctor, {"12345678"}, {"1234", "5678"}); })
        .then([=] { return assert_split(ctor, {"12345678", "9"}, {"1234", "5678", "9"}); })
        .then([=] { return assert_split(ctor, {"1234", "567890"}, {"1234", "5678", "90"}); })
        ;
}

SEASTAR_TEST_CASE(test_flush_on_empty_buffer_does_not_push_empty_packet_down_stream) {
    auto v = make_shared<std::vector<packet>>();
    auto out = make_shared<output_stream<char>>(
        data_sink(std::make_unique<vector_data_sink>(*v)), 8);

    return out->flush().then([v, out] {
        BOOST_REQUIRE(v->empty());
        return out->close();
    }).finally([out]{});
}