#include <iomanip>

#include <common/logger_useful.h>

#include <Common/SipHash.h>
#include <Common/StringUtils/StringUtils.h>
#include <IO/ReadHelpers.h>
#include <Interpreters/Quota.h>

#include <set>
#include <random>


namespace DB
{

namespace ErrorCodes
{
    extern const int QUOTA_EXPIRED;
    extern const int QUOTA_DOESNT_ALLOW_KEYS;
    extern const int UNKNOWN_QUOTA;
}


template <typename Counter>
void QuotaValues<Counter>::initFromConfig(const String & config_elem, const Poco::Util::AbstractConfiguration & config)
{
    queries             = config.getUInt64(config_elem + ".queries",        0);
    errors              = config.getUInt64(config_elem + ".errors",         0);
    result_rows         = config.getUInt64(config_elem + ".result_rows",    0);
    result_bytes        = config.getUInt64(config_elem + ".result_bytes",   0);
    read_rows           = config.getUInt64(config_elem + ".read_rows",      0);
    read_bytes          = config.getUInt64(config_elem + ".read_bytes",     0);
    execution_time_usec = config.getUInt64(config_elem + ".execution_time", 0) * 1000000ULL;
}

template void QuotaValues<size_t>::initFromConfig(const String & config_elem, const Poco::Util::AbstractConfiguration & config);
template void QuotaValues<std::atomic<size_t>>::initFromConfig(const String & config_elem, const Poco::Util::AbstractConfiguration & config);


void QuotaForInterval::initFromConfig(
    const String & config_elem, time_t duration_, bool randomize_, time_t offset_, const Poco::Util::AbstractConfiguration & config)
{
    rounded_time.store(0, std::memory_order_relaxed);
    duration = duration_;
    randomize = randomize_;
    offset = offset_;
    max.initFromConfig(config_elem, config);
}

void QuotaForInterval::checkExceeded(time_t current_time, const String & quota_name, const String & user_name)
{
    updateTime(current_time);
    check(max.queries, used.queries, quota_name, user_name, "Queries");
    check(max.errors, used.errors, quota_name, user_name, "Errors");
    check(max.result_rows, used.result_rows, quota_name, user_name, "Total result rows");
    check(max.result_bytes, used.result_bytes, quota_name, user_name, "Total result bytes");
    check(max.read_rows, used.read_rows, quota_name, user_name, "Total rows read");
    check(max.read_bytes, used.read_bytes, quota_name, user_name, "Total bytes read");
    check(max.execution_time_usec / 1000000, used.execution_time_usec / 1000000, quota_name, user_name, "Total execution time");
}

String QuotaForInterval::toString() const
{
    std::stringstream res;

    auto loaded_rounded_time = rounded_time.load(std::memory_order_relaxed);

    res << std::fixed << std::setprecision(3)
        << "Interval:       " << LocalDateTime(loaded_rounded_time) << " - " << LocalDateTime(loaded_rounded_time + duration) << ".\n"
        << "Queries:        " << used.queries         << ".\n"
        << "Errors:         " << used.errors         << ".\n"
        << "Result rows:    " << used.result_rows     << ".\n"
        << "Result bytes:   " << used.result_bytes     << ".\n"
        << "Read rows:      " << used.read_rows     << ".\n"
        << "Read bytes:     " << used.read_bytes     << ".\n"
        << "Execution time: " << used.execution_time_usec / 1000000.0 << " sec.\n";

    return res.str();
}

void QuotaForInterval::addQuery() noexcept
{
    ++used.queries;
}

void QuotaForInterval::addError() noexcept
{
    ++used.errors;
}

void QuotaForInterval::checkAndAddResultRowsBytes(time_t current_time, const String & quota_name, const String & user_name, size_t rows, size_t bytes)
{
    used.result_rows += rows;
    used.result_bytes += bytes;
    checkExceeded(current_time, quota_name, user_name);
}

void QuotaForInterval::checkAndAddReadRowsBytes(time_t current_time, const String & quota_name, const String & user_name, size_t rows, size_t bytes)
{
    used.read_rows += rows;
    used.read_bytes += bytes;
    checkExceeded(current_time, quota_name, user_name);
}

void QuotaForInterval::checkAndAddExecutionTime(time_t current_time, const String & quota_name, const String & user_name, Poco::Timespan amount)
{
    /// Information about internals of Poco::Timespan used.
    used.execution_time_usec += amount.totalMicroseconds();
    checkExceeded(current_time, quota_name, user_name);
}

void QuotaForInterval::updateTime(time_t current_time)
{
    /** If current time is greater than end of interval,
      *  then clear accumulated quota values and switch to next interval [rounded_time, rounded_time + duration).
      */

    auto loaded_rounded_time = rounded_time.load(std::memory_order_acquire);
    while (true)
    {
        if (current_time < loaded_rounded_time + static_cast<time_t>(duration))
            break;

        time_t new_rounded_time = (current_time - offset) / duration * duration + offset;
        if (rounded_time.compare_exchange_strong(loaded_rounded_time, new_rounded_time))
        {
            used.clear();
            break;
        }
    }
}

void QuotaForInterval::check(
    size_t max_amount, size_t used_amount,
    const String & quota_name, const String & user_name, const char * resource_name)
{
    if (max_amount && used_amount > max_amount)
    {
        std::stringstream message;
        message << "Quota for user '" << user_name << "' for ";

        if (duration == 3600)
            message << "1 hour";
        else if (duration == 60)
            message << "1 minute";
        else if (duration % 3600 == 0)
            message << (duration / 3600) << " hours";
        else if (duration % 60 == 0)
            message << (duration / 60) << " minutes";
        else
            message << duration << " seconds";

        message << " has been exceeded. "
            << resource_name << ": " << used_amount << ", max: " << max_amount << ". "
            << "Interval will end at " << LocalDateTime(rounded_time.load(std::memory_order_relaxed) + duration) << ". "
            << "Name of quota template: '" << quota_name << "'.";

        throw Exception(message.str(), ErrorCodes::QUOTA_EXPIRED);
    }
}


void QuotaForIntervals::initFromConfig(const String & config_elem, const Poco::Util::AbstractConfiguration & config, pcg64 & rng)
{
    Poco::Util::AbstractConfiguration::Keys config_keys;
    config.keys(config_elem, config_keys);

    for (Poco::Util::AbstractConfiguration::Keys::const_iterator it = config_keys.begin(); it != config_keys.end(); ++it)
    {
        if (!startsWith(*it, "interval"))
            continue;

        String interval_config_elem = config_elem + "." + *it;
        time_t duration = config.getInt(interval_config_elem + ".duration", 0);
        time_t offset = 0;

        if (!duration) /// Skip quotas with zero duration
            continue;

        bool randomize = config.getBool(interval_config_elem + ".randomize", false);
        if (randomize)
            offset = std::uniform_int_distribution<decltype(duration)>(0, duration - 1)(rng);

        cont[duration].initFromConfig(interval_config_elem, duration, randomize, offset, config);
    }
}

void QuotaForIntervals::setMax(const QuotaForIntervals & quota)
{
    for (Container::iterator it = cont.begin(); it != cont.end();)
    {
        if (quota.cont.count(it->first))
            ++it;
        else
            cont.erase(it++);
    }

    for (auto & x : quota.cont)
    {
        if (!cont.count(x.first))
            cont.emplace(x.first, x.second);
        else
            cont[x.first].max = x.second.max;
    }
}

void QuotaForIntervals::checkExceeded(time_t current_time)
{
    for (Container::reverse_iterator it = cont.rbegin(); it != cont.rend(); ++it)
        it->second.checkExceeded(current_time, quota_name, user_name);
}

void QuotaForIntervals::addQuery() noexcept
{
    for (Container::reverse_iterator it = cont.rbegin(); it != cont.rend(); ++it)
        it->second.addQuery();
}

void QuotaForIntervals::addError() noexcept
{
    for (Container::reverse_iterator it = cont.rbegin(); it != cont.rend(); ++it)
        it->second.addError();
}

void QuotaForIntervals::checkAndAddResultRowsBytes(time_t current_time, size_t rows, size_t bytes)
{
    for (Container::reverse_iterator it = cont.rbegin(); it != cont.rend(); ++it)
        it->second.checkAndAddResultRowsBytes(current_time, quota_name, user_name, rows, bytes);
}

void QuotaForIntervals::checkAndAddReadRowsBytes(time_t current_time, size_t rows, size_t bytes)
{
    for (Container::reverse_iterator it = cont.rbegin(); it != cont.rend(); ++it)
        it->second.checkAndAddReadRowsBytes(current_time, quota_name, user_name, rows, bytes);
}

void QuotaForIntervals::checkAndAddExecutionTime(time_t current_time, Poco::Timespan amount)
{
    for (Container::reverse_iterator it = cont.rbegin(); it != cont.rend(); ++it)
        it->second.checkAndAddExecutionTime(current_time, quota_name, user_name, amount);
}

String QuotaForIntervals::toString() const
{
    std::stringstream res;

    for (Container::const_reverse_iterator it = cont.rbegin(); it != cont.rend(); ++it)
        res << std::endl << it->second.toString();

    return res.str();
}


void Quota::loadFromConfig(const String & config_elem, const String & name_, const Poco::Util::AbstractConfiguration & config, pcg64 & rng)
{
    name = name_;

    bool new_keyed_by_ip = config.has(config_elem + ".keyed_by_ip");
    bool new_is_keyed = new_keyed_by_ip || config.has(config_elem + ".keyed");

    if (new_is_keyed != is_keyed || new_keyed_by_ip != keyed_by_ip)
    {
        keyed_by_ip = new_keyed_by_ip;
        is_keyed = new_is_keyed;
        /// Meaning of keys has been changed. Throw away accumulated values.
        quota_for_keys.clear();
    }

    ignore_key_if_not_keyed = config.has(config_elem + ".ignore_key_if_not_keyed");

    QuotaForIntervals new_max(name, {});
    new_max.initFromConfig(config_elem, config, rng);
    if (!new_max.hasEqualConfiguration(max))
    {
        max = new_max;
        for (auto & quota : quota_for_keys)
            quota.second->setMax(max);
    }
}

QuotaForIntervalsPtr Quota::get(const String & quota_key, const String & user_name, const Poco::Net::IPAddress & ip)
{
    if (!quota_key.empty() && !ignore_key_if_not_keyed && (!is_keyed || keyed_by_ip))
        throw Exception("Quota " + name + " (for user " + user_name + ") doesn't allow client supplied keys.",
            ErrorCodes::QUOTA_DOESNT_ALLOW_KEYS);

    /** Quota is calculated separately:
      * - for each IP-address, if 'keyed_by_ip';
      * - otherwise for each 'quota_key', if present;
      * - otherwise for each 'user_name'.
      */

    UInt64 quota_key_hashed = sipHash64(
        keyed_by_ip
            ? ip.toString()
            : (!quota_key.empty()
                ? quota_key
                : user_name));

    std::lock_guard lock(mutex);

    Container::iterator it = quota_for_keys.find(quota_key_hashed);
    if (quota_for_keys.end() == it)
        it = quota_for_keys.emplace(quota_key_hashed, std::make_shared<QuotaForIntervals>(max, user_name)).first;

    return it->second;
}


void Quotas::loadFromConfig(const Poco::Util::AbstractConfiguration & config)
{
    pcg64 rng;

    Poco::Util::AbstractConfiguration::Keys config_keys;
    config.keys("quotas", config_keys);

    /// Remove keys, that now absent in config.
    std::set<std::string> keys_set(config_keys.begin(), config_keys.end());
    for (Container::iterator it = cont.begin(); it != cont.end();)
    {
        if (keys_set.count(it->first))
            ++it;
        else
            cont.erase(it++);
    }

    for (Poco::Util::AbstractConfiguration::Keys::const_iterator it = config_keys.begin(); it != config_keys.end(); ++it)
    {
        if (!cont.count(*it))
            cont.try_emplace(*it);
        cont[*it].loadFromConfig("quotas." + *it, *it, config, rng);
    }
}

QuotaForIntervalsPtr Quotas::get(const String & name, const String & quota_key, const String & user_name, const Poco::Net::IPAddress & ip)
{
    Container::iterator it = cont.find(name);
    if (cont.end() == it)
        throw Exception("Unknown quota " + name, ErrorCodes::UNKNOWN_QUOTA);

    return it->second.get(quota_key, user_name, ip);
}

}