#include "perfjson.h"

#include <QHttpServer>
#include <QJsonObject>
#include <QDebug>
#include <QCoreApplication>

#include <unistd.h>
#include <sys/prctl.h>
#include <signal.h>

PerfJson::PerfJson(QHttpServer &server, QObject *parent) :
    QObject{parent}
{
    m_process.setProcessChannelMode(QProcess::MergedChannels);

    m_process.setChildProcessModifier([] {
        prctl(PR_SET_PDEATHSIG, SIGKILL);
    });

    connect(&m_process, &QProcess::started, this, &PerfJson::processStarted);
    connect(&m_process, &QProcess::finished, this, &PerfJson::processFinished);
    connect(&m_process, &QProcess::readyRead, this, &PerfJson::readyRead);

    m_process.start("sudo", {"perf", "trace", "-e", "bcachefs:error_throw", "-e", "bcachefs:write_super"});

    server.route("/perf_json", this, &PerfJson::getPerfJson);
}

void PerfJson::processStarted()
{
    qDebug() << "started";
}

void PerfJson::processFinished(int exitCode, QProcess::ExitStatus exitStatus)
{
    qDebug() << "finished exitCode =" << exitCode << "exitStatus =" << exitStatus;
    QCoreApplication::exit(exitCode);
}

void PerfJson::readyRead()
{
    while (m_process.canReadLine())
    {
        auto lineStr = m_process.readLine();

        QByteArrayView line = lineStr;
        line = line.trimmed();

        //qDebug() << "received" << line;

        qsizetype tsEnd = line.indexOf(' ');
        QByteArrayView timestamp = line.left(tsEnd);

        qsizetype lparen = line.indexOf('(', tsEnd + 1);

        qsizetype funcStart = line.lastIndexOf(' ', lparen);
        QByteArrayView function = line.mid(funcStart + 1, lparen - funcStart - 1);

        QByteArrayView thread = line.mid(tsEnd + 1, funcStart - tsEnd - 1);

        qsizetype rparen = line.lastIndexOf(')');
        QByteArrayView args = line.mid(lparen + 1, rparen - lparen - 1);

        //qDebug() << "timestamp =" << timestamp;
        //qDebug() << "thread =" << thread;
        //qDebug() << "function =" << function;
        //qDebug() << "args =" << args;

        QByteArrayView fs, str;
        while (!args.isEmpty())
        {
            qsizetype colon = args.indexOf(':');
            qsizetype quote1 = args.indexOf('"', colon);
            qsizetype quote2 = args.indexOf('"', quote1 + 1);

            QByteArrayView key   = args.left(colon).trimmed();
            QByteArrayView value = args.mid(quote1 + 1, quote2 - quote1 - 1);

            //qDebug() << "key =" << key << "value =" << value;

            if (key == "fs")
                fs = value;
            else if (key == "str")
                str = value;

            qsizetype next = args.indexOf(',', quote2);
            if (next == -1) break;
            args = args.mid(next + 1).trimmed();
        }

        if (fs.isEmpty())
            continue;

        counters[fs][function][str]++;
    }
}

QJsonObject PerfJson::getPerfJson() const
{
    auto filesystems = QJsonObject{};

    for (auto iter = std::cbegin(counters); iter != std::cend(counters); iter++)
    {
        auto functions = QJsonObject{};

        for (auto iter2 = std::cbegin(iter.value()); iter2 != std::cend(iter.value()); iter2++)
        {
            auto strs = QJsonObject{};

            for (auto iter3 = std::cbegin(iter2.value()); iter3 != std::cend(iter2.value()); iter3++)
                strs[iter3.key()] = iter3.value();

            functions[iter2.key()] = std::move(strs);
        }

        filesystems[iter.key()] = std::move(functions);
    }

    return filesystems;
}