#include <IO/ReadBufferAIO.h>
#include <Core/Defines.h>
#include <filesystem>
#include <vector>
#include <iostream>
#include <fstream>
#include <functional>
#include <cstdlib>
#include <unistd.h>


namespace
{

void run();
void prepare(std::string & filename, std::string & buf);
void prepare2(std::string & filename, std::string & buf);
void prepare3(std::string & filename, std::string & buf);
void prepare4(std::string & filename, std::string & buf);
std::string createTmpFile();
[[noreturn]] void die(const std::string & msg);
void runTest(unsigned int num, const std::function<bool()> & func);

bool test1(const std::string & filename);
bool test2(const std::string & filename, const std::string & buf);
bool test3(const std::string & filename, const std::string & buf);
bool test4(const std::string & filename, const std::string & buf);
bool test5(const std::string & filename, const std::string & buf);
bool test6(const std::string & filename, const std::string & buf);
bool test7(const std::string & filename, const std::string & buf);
bool test8(const std::string & filename, const std::string & buf);
bool test9(const std::string & filename, const std::string & buf);
bool test10(const std::string & filename, const std::string & buf);
bool test11(const std::string & filename);
bool test12(const std::string & filename, const std::string & buf);
bool test13(const std::string & filename, const std::string & buf);
bool test14(const std::string & filename, const std::string & buf);
bool test15(const std::string & filename, const std::string & buf);
bool test16(const std::string & filename, const std::string & buf);
bool test17(const std::string & filename, const std::string & buf);
bool test18(const std::string & filename, const std::string & buf);
bool test19(const std::string & filename, const std::string & buf);
bool test20(const std::string & filename, const std::string & buf);

void run()
{
    namespace fs = std::filesystem;

    std::string filename;
    std::string buf;
    prepare(filename, buf);

    std::string filename2;
    std::string buf2;
    prepare(filename2, buf2);

    std::string filename3;
    std::string buf3;
    prepare2(filename3, buf3);

    std::string filename4;
    std::string buf4;
    prepare3(filename4, buf4);

    std::string filename5;
    std::string buf5;
    prepare4(filename5, buf5);

    const std::vector<std::function<bool()>> tests =
    {
        [&]{ return test1(filename); },
        [&]{ return test2(filename, buf); },
        [&]{ return test3(filename, buf); },
        [&]{ return test4(filename, buf); },
        [&]{ return test5(filename, buf); },
        [&]{ return test6(filename, buf); },
        [&]{ return test7(filename, buf); },
        [&]{ return test8(filename, buf); },
        [&]{ return test9(filename, buf); },
        [&]{ return test10(filename, buf); },
        [&]{ return test11(filename); },
        [&]{ return test12(filename, buf); },
        [&]{ return test13(filename2, buf2); },
        [&]{ return test14(filename, buf); },
        [&]{ return test15(filename3, buf3); },
        [&]{ return test16(filename3, buf3); },
        [&]{ return test17(filename4, buf4); },
        [&]{ return test18(filename5, buf5); },
        [&]{ return test19(filename, buf); },
        [&]{ return test20(filename, buf); }
    };

    unsigned int num = 0;
    for (const auto & test : tests)
    {
        ++num;
        runTest(num, test);
    }

    fs::remove_all(fs::path(filename).parent_path().string());
    fs::remove_all(fs::path(filename2).parent_path().string());
    fs::remove_all(fs::path(filename3).parent_path().string());
    fs::remove_all(fs::path(filename4).parent_path().string());
    fs::remove_all(fs::path(filename5).parent_path().string());
}

void prepare(std::string & filename, std::string & buf)
{
    static const std::string symbols = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

    filename = createTmpFile();

    size_t n = 10 * DEFAULT_AIO_FILE_BLOCK_SIZE;
    buf.reserve(n);

    for (size_t i = 0; i < n; ++i)
        buf += symbols[i % symbols.length()];

    std::ofstream out(filename.c_str());
    if (!out.is_open())
        die("Could not open file");

    out << buf;
}

void prepare2(std::string & filename, std::string & buf)
{
    filename = createTmpFile();

    buf = "122333444455555666666777777788888888999999999";

    std::ofstream out(filename.c_str());
    if (!out.is_open())
        die("Could not open file");

    out << buf;
}

void prepare3(std::string & filename, std::string & buf)
{
    filename = createTmpFile();

    buf = "122333444455555666666777777788888888999999999";

    std::ofstream out(filename.c_str());
    if (!out.is_open())
        die("Could not open file");

    out.seekp(7, std::ios_base::beg);
    out << buf;
}

void prepare4(std::string & filename, std::string & buf)
{
    static const std::string symbols = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";

    filename = createTmpFile();

    std::ofstream out(filename.c_str());
    if (!out.is_open())
        die("Could not open file");

    for (size_t i = 0; i < 1340; ++i)
        buf += symbols[i % symbols.length()];

    out.seekp(2984, std::ios_base::beg);
    out << buf;
}

std::string createTmpFile()
{
    char pattern[] = "/tmp/fileXXXXXX";
    char * dir = ::mkdtemp(pattern);
    if (dir == nullptr)
        die("Could not create directory");

    return std::string(dir) + "/foo";
}

void die(const std::string & msg)
{
    std::cout << msg << "\n";
    ::exit(EXIT_FAILURE);
}

void runTest(unsigned int num, const std::function<bool()> & func)
{
    bool ok;

    try
    {
        ok = func();
    }
    catch (const DB::Exception & ex)
    {
        ok = false;
        std::cout << "Caught exception " << ex.displayText() << "\n";
    }
    catch (const std::exception & ex)
    {
        ok = false;
        std::cout << "Caught exception " << ex.what() << "\n";
    }

    if (ok)
        std::cout << "Test " << num << " passed\n";
    else
        std::cout << "Test " << num << " failed\n";
}

bool test1(const std::string & filename)
{
    DB::ReadBufferAIO in(filename, 3 * DEFAULT_AIO_FILE_BLOCK_SIZE);
    if (in.getFileName() != filename)
        return false;
    if (in.getFD() == -1)
        return false;
    return true;
}

bool test2(const std::string & filename, const std::string & buf)
{
    std::string newbuf;
    newbuf.resize(buf.length());

    DB::ReadBufferAIO in(filename, 3 * DEFAULT_AIO_FILE_BLOCK_SIZE);
    size_t count = in.read(newbuf.data(), newbuf.length());
    if (count != newbuf.length())
        return false;

    return (newbuf == buf);
}

bool test3(const std::string & filename, const std::string & buf)
{
    std::string newbuf;
    newbuf.resize(buf.length());

    size_t requested = 9 * DEFAULT_AIO_FILE_BLOCK_SIZE;

    DB::ReadBufferAIO in(filename, 3 * DEFAULT_AIO_FILE_BLOCK_SIZE);
    in.setMaxBytes(requested);
    size_t count = in.read(newbuf.data(), newbuf.length());

    newbuf.resize(count);
    return (newbuf == buf.substr(0, requested));
}

bool test4(const std::string & filename, const std::string & buf)
{
    std::string newbuf;
    newbuf.resize(buf.length());

    DB::ReadBufferAIO in(filename, 3 * DEFAULT_AIO_FILE_BLOCK_SIZE);
    in.setMaxBytes(0);
    size_t n_read = in.read(newbuf.data(), newbuf.length());

    return n_read == 0;
}

bool test5(const std::string & filename, const std::string & buf)
{
    std::string newbuf;
    newbuf.resize(1 + (DEFAULT_AIO_FILE_BLOCK_SIZE >> 1));

    DB::ReadBufferAIO in(filename, DEFAULT_AIO_FILE_BLOCK_SIZE);
    in.setMaxBytes(1 + (DEFAULT_AIO_FILE_BLOCK_SIZE >> 1));

    size_t count = in.read(newbuf.data(), newbuf.length());
    if (count != newbuf.length())
        return false;

    if (newbuf != buf.substr(0, newbuf.length()))
        return false;

    return true;
}

bool test6(const std::string & filename, const std::string & buf)
{
    std::string newbuf;
    newbuf.resize(buf.length());

    DB::ReadBufferAIO in(filename, 3 * DEFAULT_AIO_FILE_BLOCK_SIZE);

    if (in.getPosition() != 0)
        return false;

    size_t count = in.read(newbuf.data(), newbuf.length());
    if (count != newbuf.length())
        return false;

    if (static_cast<size_t>(in.getPosition()) != buf.length())
        return false;

    return true;
}

bool test7(const std::string & filename, const std::string & buf)
{
    std::string newbuf;
    newbuf.resize(buf.length() - DEFAULT_AIO_FILE_BLOCK_SIZE);

    DB::ReadBufferAIO in(filename, 3 * DEFAULT_AIO_FILE_BLOCK_SIZE);
    (void) in.seek(DEFAULT_AIO_FILE_BLOCK_SIZE, SEEK_SET);
    size_t count = in.read(newbuf.data(), newbuf.length());
    if (count != (9 * DEFAULT_AIO_FILE_BLOCK_SIZE))
        return false;

    return (newbuf == buf.substr(DEFAULT_AIO_FILE_BLOCK_SIZE));
}

bool test8(const std::string & filename, const std::string & buf)
{
    std::string newbuf;
    newbuf.resize(DEFAULT_AIO_FILE_BLOCK_SIZE - 1);

    DB::ReadBufferAIO in(filename, 3 * DEFAULT_AIO_FILE_BLOCK_SIZE);
    (void) in.seek(DEFAULT_AIO_FILE_BLOCK_SIZE + 1, SEEK_CUR);
    size_t count = in.read(newbuf.data(), newbuf.length());

    if (count != newbuf.length())
        return false;

    if (newbuf != buf.substr(DEFAULT_AIO_FILE_BLOCK_SIZE + 1, newbuf.length()))
        return false;

    return true;
}

bool test9(const std::string & filename, const std::string & buf)
{
    bool ok = false;

    try
    {
        std::string newbuf;
        newbuf.resize(buf.length());

        DB::ReadBufferAIO in(filename, 3 * DEFAULT_AIO_FILE_BLOCK_SIZE);
        size_t count = in.read(newbuf.data(), newbuf.length());
        if (count != newbuf.length())
            return false;
        in.setMaxBytes(9 * DEFAULT_AIO_FILE_BLOCK_SIZE);
    }
    catch (const DB::Exception &)
    {
        ok = true;
    }

    return ok;
}

bool test10(const std::string & filename, const std::string & buf)
{
    DB::ReadBufferAIO in(filename, 3 * DEFAULT_AIO_FILE_BLOCK_SIZE);

    {
        std::string newbuf;
        newbuf.resize(4 * DEFAULT_AIO_FILE_BLOCK_SIZE);

        size_t count1 = in.read(newbuf.data(), newbuf.length());
        if (count1 != newbuf.length())
            return false;

        if (newbuf != buf.substr(0, 4 * DEFAULT_AIO_FILE_BLOCK_SIZE))
            return false;
    }

    (void) in.seek(2 * DEFAULT_AIO_FILE_BLOCK_SIZE, SEEK_CUR);

    {
        std::string newbuf;
        newbuf.resize(4 * DEFAULT_AIO_FILE_BLOCK_SIZE);

        size_t count2 = in.read(newbuf.data(), newbuf.length());
        if (count2 != newbuf.length())
            return false;

        if (newbuf != buf.substr(6 * DEFAULT_AIO_FILE_BLOCK_SIZE))
            return false;
    }

    return true;
}

bool test11(const std::string & filename)
{
    bool ok = false;

    try
    {
        DB::ReadBufferAIO in(filename, 3 * DEFAULT_AIO_FILE_BLOCK_SIZE);
        (void) in.seek(-DEFAULT_AIO_FILE_BLOCK_SIZE, SEEK_SET);
    }
    catch (const DB::Exception &)
    {
        ok = true;
    }

    return ok;
}

bool test12(const std::string & filename, const std::string &)
{
    bool ok = false;

    try
    {
        std::string newbuf;
        newbuf.resize(4 * DEFAULT_AIO_FILE_BLOCK_SIZE);

        DB::ReadBufferAIO in(filename, 3 * DEFAULT_AIO_FILE_BLOCK_SIZE);
        size_t count = in.read(newbuf.data(), newbuf.length());
        if (count != newbuf.length())
            return false;

        (void) in.seek(-(10 * DEFAULT_AIO_FILE_BLOCK_SIZE), SEEK_CUR);
    }
    catch (const DB::Exception &)
    {
        ok = true;
    }

    return ok;
}

bool test13(const std::string & filename, const std::string &)
{
    std::string newbuf;
    newbuf.resize(2 * DEFAULT_AIO_FILE_BLOCK_SIZE - 3);

    DB::ReadBufferAIO in(filename, DEFAULT_AIO_FILE_BLOCK_SIZE);
    size_t count1 = in.read(newbuf.data(), newbuf.length());
    return count1 == newbuf.length();
}

bool test14(const std::string & filename, const std::string & buf)
{
    std::string newbuf;
    newbuf.resize(1 + (DEFAULT_AIO_FILE_BLOCK_SIZE >> 1));

    DB::ReadBufferAIO in(filename, DEFAULT_AIO_FILE_BLOCK_SIZE);
    (void) in.seek(2, SEEK_SET);
    in.setMaxBytes(3 + (DEFAULT_AIO_FILE_BLOCK_SIZE >> 1));

    size_t count = in.read(newbuf.data(), newbuf.length());
    if (count != newbuf.length())
        return false;

    if (newbuf != buf.substr(2, newbuf.length()))
        return false;

    return true;
}

bool test15(const std::string & filename, const std::string &)
{
    std::string newbuf;
    newbuf.resize(1000);

    DB::ReadBufferAIO in(filename, DEFAULT_AIO_FILE_BLOCK_SIZE);

    size_t count = in.read(newbuf.data(), 1);
    if (count != 1)
        return false;
    if (newbuf[0] != '1')
        return false;
    return true;
}

bool test16(const std::string & filename, const std::string &)
{
    DB::ReadBufferAIO in(filename, DEFAULT_AIO_FILE_BLOCK_SIZE);
    size_t count;

    {
        std::string newbuf;
        newbuf.resize(1);
        count = in.read(newbuf.data(), 1);
        if (count != 1)
            return false;
        if (newbuf[0] != '1')
            return false;
    }

    in.seek(2, SEEK_CUR);

    {
        std::string newbuf;
        newbuf.resize(3);
        count = in.read(newbuf.data(), 3);
        if (count != 3)
            return false;
        if (newbuf != "333")
            return false;
    }

    in.seek(4, SEEK_CUR);

    {
        std::string newbuf;
        newbuf.resize(5);
        count = in.read(newbuf.data(), 5);
        if (count != 5)
            return false;
        if (newbuf != "55555")
            return false;
    }

    in.seek(6, SEEK_CUR);

    {
        std::string newbuf;
        newbuf.resize(7);
        count = in.read(newbuf.data(), 7);
        if (count != 7)
            return false;
        if (newbuf != "7777777")
            return false;
    }

    in.seek(8, SEEK_CUR);

    {
        std::string newbuf;
        newbuf.resize(9);
        count = in.read(newbuf.data(), 9);
        if (count != 9)
            return false;
        if (newbuf != "999999999")
            return false;
    }

    return true;
}

bool test17(const std::string & filename, const std::string & buf)
{
    DB::ReadBufferAIO in(filename, DEFAULT_AIO_FILE_BLOCK_SIZE);
    size_t count;

    {
        std::string newbuf;
        newbuf.resize(10);
        count = in.read(newbuf.data(), 10);

        if (count != 10)
            return false;
        if (newbuf.substr(0, 7) != std::string(7, '\0'))
            return false;
        if (newbuf.substr(7) != "122")
            return false;
    }

    in.seek(7 + buf.length() - 2, SEEK_SET);

    {
        std::string newbuf;
        newbuf.resize(160);
        count = in.read(newbuf.data(), 160);

        if (count != 2)
            return false;
        if (newbuf.substr(0, 2) != "99")
            return false;
    }

    in.seek(7 + buf.length() + DEFAULT_AIO_FILE_BLOCK_SIZE, SEEK_SET);

    {
        std::string newbuf;
        newbuf.resize(50);
        count = in.read(newbuf.data(), 50);
        if (count != 0)
            return false;
    }

    return true;
}

bool test18(const std::string & filename, const std::string & buf)
{
    DB::ReadBufferAIO in(filename, DEFAULT_AIO_FILE_BLOCK_SIZE);

    std::string newbuf;
    newbuf.resize(1340);

    in.seek(2984, SEEK_SET);
    size_t count = in.read(newbuf.data(), 1340);

    if (count != 1340)
        return false;
    if (newbuf != buf)
        return false;

    return true;
}

bool test19(const std::string & filename, const std::string & buf)
{
    DB::ReadBufferAIO in(filename, 3 * DEFAULT_AIO_FILE_BLOCK_SIZE);

    {
        std::string newbuf;
        newbuf.resize(5 * DEFAULT_AIO_FILE_BLOCK_SIZE);

        size_t count1 = in.read(newbuf.data(), newbuf.length());
        if (count1 != newbuf.length())
            return false;

        if (newbuf != buf.substr(0, 5 * DEFAULT_AIO_FILE_BLOCK_SIZE))
            return false;
    }

    {
        std::string newbuf;
        newbuf.resize(5 * DEFAULT_AIO_FILE_BLOCK_SIZE);

        size_t count2 = in.read(newbuf.data(), newbuf.length());
        if (count2 != newbuf.length())
            return false;

        if (newbuf != buf.substr(5 * DEFAULT_AIO_FILE_BLOCK_SIZE))
            return false;
    }

    return true;
}

bool test20(const std::string & filename, const std::string & buf)
{
    DB::ReadBufferAIO in(filename, 3 * DEFAULT_AIO_FILE_BLOCK_SIZE);

    {
        std::string newbuf;
        newbuf.resize(5 * DEFAULT_AIO_FILE_BLOCK_SIZE);

        size_t count1 = in.read(newbuf.data(), newbuf.length());
        if (count1 != newbuf.length())
            return false;

        if (newbuf != buf.substr(0, 5 * DEFAULT_AIO_FILE_BLOCK_SIZE))
            return false;
    }

    (void) in.getPosition();

    {
        std::string newbuf;
        newbuf.resize(5 * DEFAULT_AIO_FILE_BLOCK_SIZE);

        size_t count2 = in.read(newbuf.data(), newbuf.length());
        if (count2 != newbuf.length())
            return false;

        if (newbuf != buf.substr(5 * DEFAULT_AIO_FILE_BLOCK_SIZE))
            return false;
    }

    return true;
}

}

int main()
{
    run();
    return 0;
}