#include "rpc/Counters.hpp"

#include "rpc/JS.hpp"
#include "rpc/WorkQueue.hpp"
#include "util/JsonUtils.hpp"
#include "util/prometheus/Label.hpp"
#include "util/prometheus/Prometheus.hpp"

#include <boost/json/object.hpp>
#include <boost/json/value.hpp>
#include <boost/json/value_to.hpp>
#include <fmt/format.h>
#include <xrpl/protocol/jss.h>

#include <chrono>
#include <cstdint>
#include <functional>
#include <mutex>
#include <optional>
#include <string>
#include <utility>
#include <vector>

namespace rpc {

using util::prometheus::Label;
using util::prometheus::Labels;

Counters::MethodInfo::MethodInfo(std::string const& method)
    : started(
          PrometheusService::counterInt(
              "rpc_method_total_number",
              Labels{{{"status", "started"}, {"method", method}}},
              fmt::format("Total number of started calls to the method {}", method)
          )
      )
    , finished(
          PrometheusService::counterInt(
              "rpc_method_total_number",
              Labels{{{"status", "finished"}, {"method", method}}},
              fmt::format("Total number of finished calls to the method {}", method)
          )
      )
    , failed(
          PrometheusService::counterInt(
              "rpc_method_total_number",
              Labels{{{"status", "failed"}, {"method", method}}},
              fmt::format("Total number of failed calls to the method {}", method)
          )
      )
    , errored(
          PrometheusService::counterInt(
              "rpc_method_total_number",
              Labels{{{"status", "errored"}, {"method", method}}},
              fmt::format("Total number of errored calls to the method {}", method)
          )
      )
    , forwarded(
          PrometheusService::counterInt(
              "rpc_method_total_number",
              Labels{{{"status", "forwarded"}, {"method", method}}},
              fmt::format("Total number of forwarded calls to the method {}", method)
          )
      )
    , failedForward(
          PrometheusService::counterInt(
              "rpc_method_total_number",
              Labels{{{"status", "failed_forward"}, {"method", method}}},
              fmt::format("Total number of failed forwarded calls to the method {}", method)
          )
      )
    , duration(
          PrometheusService::counterInt(
              "rpc_method_duration_us",
              Labels({util::prometheus::Label{"method", method}}),
              fmt::format("Total duration of calls to the method {}", method)
          )
      )
{
}

Counters::MethodInfo&
Counters::getMethodInfo(std::string const& method)
{
    auto it = methodInfo_.find(method);
    if (it == methodInfo_.end()) {
        it = methodInfo_.emplace(method, MethodInfo(method)).first;
    }
    return it->second;
}

Counters::Counters(Reportable const& wq)
    : tooBusyCounter_(
          PrometheusService::counterInt(
              "rpc_error_total_number",
              Labels({Label{"error_type", "too_busy"}}),
              "Total number of too busy errors"
          )
      )
    , notReadyCounter_(
          PrometheusService::counterInt(
              "rpc_error_total_number",
              Labels({Label{"error_type", "not_ready"}}),
              "Total number of not ready replyes"
          )
      )
    , badSyntaxCounter_(
          PrometheusService::counterInt(
              "rpc_error_total_number",
              Labels({Label{"error_type", "bad_syntax"}}),
              "Total number of bad syntax replyes"
          )
      )
    , unknownCommandCounter_(
          PrometheusService::counterInt(
              "rpc_error_total_number",
              Labels({Label{"error_type", "unknown_command"}}),
              "Total number of unknown command replyes"
          )
      )
    , internalErrorCounter_(
          PrometheusService::counterInt(
              "rpc_error_total_number",
              Labels({Label{"error_type", "internal_error"}}),
              "Total number of internal errors"
          )
      )
    , ledgerAgeLedgersHistogram_(
          PrometheusService::histogramInt(
              "rpc_requested_ledger_age_histogram",
              Labels{},
              {0, 10, 100, 1'000, 10'000, 100'000, 1'000'000, 10'000'000, 100'000'000},
              "Age of requested ledgers in ledger count"
          )
      )
    , ledgerHashRequestsCounter_(
          PrometheusService::counterInt(
              "rpc_ledger_hash_requests_total_number",
              Labels{},
              "Total number of successful requests containing ledger_hash field"
          )
      )
    , workQueue_(std::cref(wq))
    , startupTime_{std::chrono::system_clock::now()}
{
}

void
Counters::rpcFailed(std::string const& method)
{
    std::scoped_lock const lk(mutex_);
    MethodInfo const& counters = getMethodInfo(method);
    ++counters.started.get();
    ++counters.failed.get();
}

void
Counters::rpcErrored(std::string const& method)
{
    std::scoped_lock const lk(mutex_);
    MethodInfo const& counters = getMethodInfo(method);
    ++counters.started.get();
    ++counters.errored.get();
}

void
Counters::rpcComplete(std::string const& method, std::chrono::microseconds const& rpcDuration)
{
    std::scoped_lock const lk(mutex_);
    MethodInfo const& counters = getMethodInfo(method);
    ++counters.started.get();
    ++counters.finished.get();
    counters.duration.get() += rpcDuration.count();
}

void
Counters::rpcForwarded(std::string const& method)
{
    std::scoped_lock const lk(mutex_);
    MethodInfo const& counters = getMethodInfo(method);
    ++counters.forwarded.get();
}

void
Counters::rpcFailedToForward(std::string const& method)
{
    std::scoped_lock const lk(mutex_);
    MethodInfo const& counters = getMethodInfo(method);
    ++counters.failedForward.get();
}

void
Counters::onTooBusy()
{
    ++tooBusyCounter_.get();
}

void
Counters::onNotReady()
{
    ++notReadyCounter_.get();
}

void
Counters::onBadSyntax()
{
    ++badSyntaxCounter_.get();
}

void
Counters::onUnknownCommand()
{
    ++unknownCommandCounter_.get();
}

void
Counters::onInternalError()
{
    ++internalErrorCounter_.get();
}

void
Counters::recordLedgerRequest(
    boost::json::object const& params,
    std::uint32_t currentLedgerSequence
)
{
    if (params.contains(JS(ledger_hash))) {
        ++ledgerHashRequestsCounter_.get();
        return;
    }

    if (not params.contains(JS(ledger_index))) {
        ledgerAgeLedgersHistogram_.get().observe(0);
        return;
    }
    auto const& indexValue = params.at("ledger_index");
    if (auto const parsed = util::getLedgerIndex(indexValue); parsed.has_value()) {
        if (*parsed <= currentLedgerSequence) {
            auto const ageLedgers = static_cast<std::int64_t>(currentLedgerSequence - *parsed);
            ledgerAgeLedgersHistogram_.get().observe(ageLedgers);
        }
    } else if (indexValue.is_string()) {
        auto const indexStr = boost::json::value_to<std::string>(indexValue);
        if (indexStr == "validated") {
            ledgerAgeLedgersHistogram_.get().observe(0);
        }
    }
}

std::chrono::seconds
Counters::uptime() const
{
    return std::chrono::duration_cast<std::chrono::seconds>(
        std::chrono::system_clock::now() - startupTime_
    );
}

boost::json::object
Counters::report() const
{
    std::scoped_lock const lk(mutex_);
    auto obj = boost::json::object{};

    obj[JS(rpc)] = boost::json::object{};
    auto& rpc = obj[JS(rpc)].as_object();

    for (auto const& [method, info] : methodInfo_) {
        auto counters = boost::json::object{};
        counters[JS(started)] = std::to_string(info.started.get().value());
        counters[JS(finished)] = std::to_string(info.finished.get().value());
        counters[JS(errored)] = std::to_string(info.errored.get().value());
        counters[JS(failed)] = std::to_string(info.failed.get().value());
        counters["forwarded"] = std::to_string(info.forwarded.get().value());
        counters["failed_forward"] = std::to_string(info.failedForward.get().value());
        counters[JS(duration_us)] = std::to_string(info.duration.get().value());

        rpc[method] = std::move(counters);
    }

    obj["too_busy_errors"] = std::to_string(tooBusyCounter_.get().value());
    obj["not_ready_errors"] = std::to_string(notReadyCounter_.get().value());
    obj["bad_syntax_errors"] = std::to_string(badSyntaxCounter_.get().value());
    obj["unknown_command_errors"] = std::to_string(unknownCommandCounter_.get().value());
    obj["internal_errors"] = std::to_string(internalErrorCounter_.get().value());

    obj["work_queue"] = workQueue_.get().report();

    return obj;
}

}  // namespace rpc