/*
    SPDX-License-Identifier: GPL-2.0-or-later
    SPDX-FileCopyrightText: 2009-2012 Alexander Rieder <alexanderrieder@gmail.com>
    SPDX-FileCopyrightText: 2017-2022 by Alexander Semke (alexander.semke@web.de)
*/

#include "maximaexpression.h"

#include <config-cantorlib.h>

#include "maximasession.h"
#include "textresult.h"
#include "epsresult.h"
#include "imageresult.h"
#include "helpresult.h"
#include "latexresult.h"
#include "settings.h"

#include <QDir>
#include <QTemporaryFile>

#include <KLocalizedString>
#include <QDebug>
#include <QTimer>
#include <QRegularExpression>
#include <QChar>
#include <QUrl>

// MaximaExpression use real id from Maxima as expression id, so we don't know id before executing
MaximaExpression::MaximaExpression( Cantor::Session* session, bool internal ) : Cantor::Expression(session, internal, -1)
{
}

MaximaExpression::~MaximaExpression() {
    if(m_tempFile)
        delete m_tempFile;
}

void MaximaExpression::evaluate()
{
    m_gotErrorContent = false;

    if(m_tempFile)
    {
        delete m_tempFile;
        m_tempFile = nullptr;
        m_isPlot = false;
        m_plotResult = nullptr;
        m_plotResultIndex = -1;
    }

    QString cmd = command();

    //if the user explicitly has entered quit(), do a logout here
    //otherwise maxima's process will be stopped after the evaluation of this command
    //and we re-start it because of "maxima has crashed".
    if (cmd.remove(QLatin1Char(' ')) == QLatin1String("quit()"))
    {
        session()->logout();
        return;
    }

    //check if this is a ?command
    if(cmd.startsWith(QLatin1String("??"))
        || cmd.startsWith(QLatin1String("describe("))
        || cmd.startsWith(QLatin1String("example("))
        || cmd.startsWith(QLatin1String(":lisp(cl-info::info-exact")))
        setIsHelpRequest(true);

    if (MaximaSettings::self()->integratePlots()
        && !cmd.contains(QLatin1String("ps_file"))
        && cmd.contains(QRegularExpression(QStringLiteral("(?:plot2d|plot3d|contour_plot|draw|draw2d|draw3d)\\s*\\([^\\)]"))))
    {
        m_isPlot = true;
        if (cmd.contains(QRegularExpression(QStringLiteral("(?:draw|draw2d|draw3d)\\s*\\([^\\)]"))))
            m_isDraw = true;

        m_tempFile = new QTemporaryFile(QDir::tempPath() + QLatin1String("/cantor_maxima-XXXXXX.png"));
        m_tempFile->open();

        m_fileWatch.removePaths(m_fileWatch.files());
        m_fileWatch.addPath(m_tempFile->fileName());
        connect(&m_fileWatch, &QFileSystemWatcher::fileChanged, this, &MaximaExpression::imageChanged,  Qt::UniqueConnection);
    }

    bool isComment = true;
    int commentLevel = 0;
    bool inString = false;
    for (int i = 0; i < cmd.size(); ++i) {
        if (cmd[i] == QLatin1Char('\\')) {
            ++i; // skip the next character
            if (commentLevel == 0 && !inString) {
                isComment = false;
            }
        } else if (cmd[i] == QLatin1Char('"') && commentLevel == 0) {
            inString = !inString;
            isComment = false;
        } else if (cmd.mid(i,2) == QLatin1String("/*") && !inString) {
            ++commentLevel;
            ++i;
        } else if (cmd.mid(i,2) == QLatin1String("*/") && !inString) {
            if (commentLevel == 0) {
                qDebug() << "Comments mismatched!";
                setErrorMessage(i18n("Error: Too many */"));
                setStatus(Cantor::Expression::Error);
                return;
            }
            ++i;
            --commentLevel;
        } else if (isComment && commentLevel == 0 && !cmd[i].isSpace()) {
            isComment = false;
        }
    }

    if (commentLevel > 0) {
        qDebug() << "Comments mismatched!";
        setErrorMessage(i18n("Error: Too many /*"));
        setStatus(Cantor::Expression::Error);
        return;
    }
    if (inString) {
        qDebug() << "String not closed";
        setErrorMessage(i18n("Error: expected \" before ;"));
        setStatus(Cantor::Expression::Error);
        return;
    }
    if(isComment)
    {
        setStatus(Cantor::Expression::Done);
        return;
    }

    session()->enqueueExpression(this);
}

void MaximaExpression::interrupt()
{
    qDebug()<<"interrupting";
    setStatus(Cantor::Expression::Interrupted);
}

QString MaximaExpression::internalCommand()
{
    QString cmd=command();

    if(m_isPlot)
    {
        if(!m_tempFile)
        {
            qDebug()<<"plotting without tempFile";
            return QString();
        }


        /*
        const QString pdfParam = QLatin1String("[gnuplot_pdf_term_command, \"set term pdfcairo size 9cm, 6cm\"]"); // size 5.9in, 4.7in
        const QString plotParameters = QLatin1String("[pdf_file, \"") + fileName + QLatin1String("\"], ") + pdfParam;
        */

        if (!m_isDraw)
        {
            const QString plotParameters = QLatin1String("[gnuplot_png_term_command, \"set term png size 500,340\"], [png_file, \"") + m_tempFile->fileName() + QLatin1String("\"]");
            cmd.replace(QRegularExpression(QStringLiteral("((plot2d|plot3d|contour_plot)\\s*\\(.*)\\)([;\n$]|$)")),
                        QLatin1String("\\1, ") + plotParameters + QLatin1String(");"));
        }
        else
        {
            //strip off the extension ".png", the terminal parameter for draw() is adding the extension additionally
            QString fileName = m_tempFile->fileName();
            fileName = fileName.left(fileName.length() - 4);
            const QString plotParameters = QLatin1String("terminal=png, file_name = \"") + fileName + QLatin1String("\"");
            cmd.replace(QRegularExpression(QStringLiteral("((draw|draw2d|draw3d)\\s*\\(.*)*\\)([;\n$]|$)")),
                        QLatin1String("\\1, ") + plotParameters + QLatin1String(");"));
        }

    }

    if (!cmd.endsWith(QLatin1Char('$')))
    {
        if (!cmd.endsWith(QLatin1String(";")))
            cmd+=QLatin1Char(';');
    }

    //replace all newlines with spaces, as maxima isn't sensitive about
    //whitespaces, and without newlines the whole command
    //is executed at once, without outputting an input
    //prompt after each line
    cmd.replace(QLatin1Char('\n'), QLatin1Char(' '));

    //lisp-quiet doesn't print a prompt after the command
    //is completed, which causes the parsing to hang.
    //replace the command with the non-quiet version
    cmd.replace(QRegularExpression(QStringLiteral("^:lisp-quiet")), QStringLiteral(":lisp"));

    return cmd;
}

void MaximaExpression::forceDone()
{
    qDebug()<<"forcing Expression state to DONE";
    setResult(nullptr);
    setStatus(Cantor::Expression::Done);
}

/*!
    example output for the simple expression '5+5':
    latex mode - "<cantor-result><cantor-text>\n(%o1) 10\n</cantor-text><cantor-latex>\\mbox{\\tt\\red(\\mathrm{\\%o1}) \\black}10</cantor-latex></cantor-result>\n<cantor-prompt>(%i2) </cantor-prompt>\n"
    text mode  - "<cantor-result><cantor-text>\n(%o1) 10\n</cantor-text></cantor-result>\n<cantor-prompt>(%i2) </cantor-prompt>\n"
 */
void MaximaExpression::parseOutput(const QString& out)
{
    const int promptStart = out.indexOf(QLatin1String("<cantor-prompt>"));
    const int promptEnd = out.indexOf(QLatin1String("</cantor-prompt>"));
    const QString prompt = out.mid(promptStart + 15, promptEnd - promptStart - 15).simplified();

    //check whether the result is part of the promt - this is the case when additional input is required from the user
    if (prompt.contains(QLatin1String("<cantor-result>")))
    {
        //text part of the output
        const int textContentStart = prompt.indexOf(QLatin1String("<cantor-text>"));
        const int textContentEnd = prompt.indexOf(QLatin1String("</cantor-text>"));
        QString textContent = prompt.mid(textContentStart + 13, textContentEnd - textContentStart - 13).trimmed();

        qDebug()<<"asking for additional input for " << textContent;
        emit needsAdditionalInformation(textContent);
        return;
    }

    qDebug()<<"new input label: " << prompt;

    QString errorContent;

    //parse the results
    int resultStart = out.indexOf(QLatin1String("<cantor-result>"));
    if (resultStart != -1) {
        errorContent += out.mid(0, resultStart);
        if (!errorContent.isEmpty() && !(isHelpRequest() || m_isHelpRequestAdditional))
        {
            //there is a result but also the error buffer is not empty. This is the case when
            //warnings are generated, for example, the output of rat(0.75*10) is:
            //"\nrat: replaced 7.5 by 15/2 = 7.5\n<cantor-result><cantor-text>\n(%o2) 15/2\n</cantor-text></cantor-result>\n<cantor-prompt>(%i3) </cantor-prompt>\n".
            //In such cases we just add a new text result with the warning.
            qDebug() << "warning: " << errorContent;
            auto* result = new Cantor::TextResult(errorContent.trimmed());

            //the output of tex() function is also placed outside of the result section, don't treat it as a warning
            if (!command().remove(QLatin1Char(' ')).startsWith(QLatin1String("tex(")))
                result->setIsWarning(true);
            addResult(result);
        }
    }

    while (resultStart != -1)
    {
        int resultEnd = out.indexOf(QLatin1String("</cantor-result>"), resultStart + 15);
        const QString resultContent = out.mid(resultStart + 15, resultEnd - resultStart - 15);
        parseResult(resultContent);

        //search for the next openning <cantor-result> tag after the current closing </cantor-result> tag
        resultStart = out.indexOf(QLatin1String("<cantor-result>"), resultEnd + 16);
    }

    //parse the error message, the part outside of the <cantor*> tags
    int lastResultEnd = out.lastIndexOf(QLatin1String("</cantor-result>"));
    if (lastResultEnd != -1)
        lastResultEnd += 16;
    else
        lastResultEnd = 0;

    errorContent += out.mid(lastResultEnd, promptStart - lastResultEnd).trimmed();
    if (errorContent.isEmpty())
    {
        // For plots we set Done status in imageChanged
        if (!m_isPlot || m_plotResult)
            setStatus(Cantor::Expression::Done);
    }
    else
    {
        qDebug() << "error content: " << errorContent;

        if (out.contains(QLatin1String("cantor-value-separator"))
            || (out.contains(QLatin1String("<cantor-result>")) && !(isHelpRequest() || m_isHelpRequestAdditional)) )
        {
            //we don't interpret the error output as an error in the following cases:
            //1. when fetching variables, in addition to the actual result with variable names and values,
            //  Maxima also writes out the names of the variables to the error buffer.
            //2. when there is a valid result produced, in this case the error string
            //  contains actually a warning that is handled above
            setStatus(Cantor::Expression::Done);
        }
        else if (prompt.trimmed() == QLatin1String("MAXIMA>") )
        {
            //prompt is "MAXIMA>", i.e. we're switching to the Lisp-mode triggered by to_lisp(). The output in this case is:
            //   "Type (to-maxima) to restart, ($quit) to quit Maxima.\n<cantor-prompt>\nMAXIMA> </cantor-prompt>\n"
            //Or we're already in the Lisp mode and just need to show the result of the lisp evaluation.
            if (static_cast<MaximaSession*>(session())->mode() != MaximaSession::Lisp)
                static_cast<MaximaSession*>(session())->setMode(MaximaSession::Lisp);

            auto* result = new Cantor::TextResult(errorContent.trimmed());
            setResult(result);
            qDebug()<<"setting status to DONE";
            setStatus(Cantor::Expression::Done);
        }
        else if (prompt.trimmed() != QLatin1String("MAXIMA>") && static_cast<MaximaSession*>(session())->mode() == MaximaSession::Lisp)
        {
            //"Returning to Maxima:
            //output:  "Returning to Maxima\n<cantor-result><cantor-text>\n(%o1) true\n</cantor-text></cantor-result>\n<cantor-prompt>(%i2) </cantor-prompt>\n"
            static_cast<MaximaSession*>(session())->setMode(MaximaSession::Maxima);
            auto* result = new Cantor::TextResult(errorContent.trimmed());
            addResult(result);
            setStatus(Cantor::Expression::Done);
        }
        else if(isHelpRequest() || m_isHelpRequestAdditional) //help messages are also part of the error output
        {
            //we've got help result, but maybe additional input is required -> check this
            const int index = prompt.trimmed().indexOf(MaximaSession::MaximaInputPrompt);
            if (index == -1) {
                // No input label found in the prompt -> additional info is required
                qDebug()<<"asking for additional input for the help request" << prompt;
                m_isHelpRequestAdditional = true;
                emit needsAdditionalInformation(prompt);
            }

            //set the help result
            errorContent.prepend(QLatin1Char(' '));
            auto* result = new Cantor::HelpResult(errorContent);
            setResult(result);

            //if a new input prompt was found, no further input is expected and we're done
            if (index != -1) {
                m_isHelpRequestAdditional = false;
                setStatus(Cantor::Expression::Done);
            }
        }
        else
        {
            if (isInternal())
                setStatus(Cantor::Expression::Done); //for internal commands no need to handle the error output
            else
            {
                errorContent = errorContent.replace(QLatin1String("\n\n"), QLatin1String("\n"));
                setErrorMessage(errorContent);
                setStatus(Cantor::Expression::Error);
            }
        }
    }
}

void MaximaExpression::parseResult(const QString& resultContent)
{
    //in case we asked for additional input for the help request,
    //no need to process the result - we're not done yet and maxima is waiting for further input
    if (m_isHelpRequestAdditional)
        return;

    qDebug()<<"result content: " << resultContent;

    //text part of the output
    const int textContentStart = resultContent.indexOf(QLatin1String("<cantor-text>"));
    const int textContentEnd = resultContent.indexOf(QLatin1String("</cantor-text>"));
    QString textContent = resultContent.mid(textContentStart + 13, textContentEnd - textContentStart - 13).trimmed();
    qDebug()<<"text content: " << textContent;

    //output label can be a part of the text content -> determine it
    const QRegularExpression regex = QRegularExpression(MaximaSession::MaximaOutputPrompt.pattern());
    QRegularExpressionMatch match = regex.match(textContent);
    QString outputLabel;
    if (match.hasMatch()) // a match is found, so the output contains output label
        outputLabel = textContent.mid(match.capturedStart(0), match.capturedLength(0)).trimmed();
    qDebug()<<"output label: " << outputLabel;

    //extract the expression id
    bool ok;
    QString idString = outputLabel.mid(3, outputLabel.length()-4);
    int id = idString.toInt(&ok);
    if (ok)
        setId(id);

    qDebug()<<"expression id: " << this->id();

    //remove the output label from the text content
    textContent = textContent.remove(outputLabel).trimmed();

    //determine the actual result
    Cantor::Result* result = nullptr;

    const int latexContentStart = resultContent.indexOf(QLatin1String("<cantor-latex>"));
    //Handle system maxima output for plotting commands
    if (m_isPlot)
    {
        // plot/draw command can be part of a multi-line input having other non-plot related commands.
        // parse the output of every command of the multi-line input and only add plot result if
        // the output has plot/draw specific keywords
        if ( (!m_isDraw && textContent.endsWith(QString::fromLatin1("\"%1\"]").arg(m_tempFile->fileName())))
            || (m_isDraw && (textContent.startsWith(QLatin1String("[gr2d(explicit")) || textContent.startsWith(QLatin1String("[gr3d(explicit"))) ) )
        {
            m_plotResultIndex = results().size();
            // Gnuplot could generate plot before we parse text output from maxima and after
            // If we already have plot result, just add it
            // Else set info message, and replace it by real result in imageChanged function later
            if (m_plotResult)
                result = m_plotResult;
            else
                result = new Cantor::TextResult(i18n("Waiting for the plot result"));
        }
        else
            result = new Cantor::TextResult(textContent);
    }
    else if (latexContentStart != -1)
    {
        //latex output is available
        const int latexContentEnd = resultContent.indexOf(QLatin1String("</cantor-latex>"));
        QString latexContent = resultContent.mid(latexContentStart + 14, latexContentEnd - latexContentStart - 14).trimmed();
        qDebug()<<"latex content: " << latexContent;

        Cantor::TextResult* textResult;
        //replace the \mbox{} environment, if available, by the eqnarray environment
        if (latexContent.indexOf(QLatin1String("\\mbox{")) != -1)
        {
            int i;
            int pcount=0;
            for(i = latexContent.indexOf(QLatin1String("\\mbox{"))+5; i < latexContent.size(); ++i)
            {
                if(latexContent[i]==QLatin1Char('{'))
                    pcount++;
                else if(latexContent[i]==QLatin1Char('}'))
                    pcount--;


                if(pcount==0)
                    break;
            }

            QString modifiedLatexContent = latexContent.mid(i+1);
            if(modifiedLatexContent.trimmed().isEmpty())
            {
                //empty content in the \mbox{} environment (e.g. for print() outputs), use the latex string outside of the \mbox{} environment
                modifiedLatexContent = latexContent.left(latexContent.indexOf(QLatin1String("\\mbox{")));
            }

            modifiedLatexContent.prepend(QLatin1String("\\begin{eqnarray*}"));
            modifiedLatexContent.append(QLatin1String("\\end{eqnarray*}"));
            textResult = new Cantor::TextResult(modifiedLatexContent, textContent);
            qDebug()<<"modified latex content: " << modifiedLatexContent;
        }
        else
        {
            //no \mbox{} available, use what we've got.
            textResult = new Cantor::TextResult(latexContent, textContent);
        }

        textResult->setFormat(Cantor::TextResult::LatexFormat);
        result = textResult;
    }
    else
    {
        //no latex output is available, the actual result is part of the textContent string

        // text output is quoted by Maxima, remove the quotes. No need to do it for internal
        // commands to fetch the list of current variables, the proper parsing is done in MaximaVariableModel::parse().
        if (!isInternal() && textContent.startsWith(QLatin1String("\"")))
        {
            textContent.remove(0, 1);
            textContent.chop(1);
            textContent.replace(QLatin1String("\\\""), QLatin1String("\""));
        }

        result = new Cantor::TextResult(textContent);
    }

    addResult(result);
}

void MaximaExpression::parseError(const QString& out)
{
    m_errorBuffer.append(out);
}

void MaximaExpression::addInformation(const QString& information)
{
    qDebug()<<"adding information";
    QString inf=information;
    if(!inf.endsWith(QLatin1Char(';')))
        inf+=QLatin1Char(';');
    Cantor::Expression::addInformation(inf);

    static_cast<MaximaSession*>(session())->sendInputToProcess(inf+QLatin1Char('\n'));
}

void MaximaExpression::imageChanged()
{
    if(m_tempFile->size()>0)
    {
        m_plotResult = new Cantor::ImageResult( QUrl::fromLocalFile(m_tempFile->fileName()) );
        /*
        QSizeF size;
        const QImage& image = Cantor::Renderer::pdfRenderToImage(QUrl::fromLocalFile(m_tempFile->fileName()), 1., false, &size);
        m_plotResult = new Cantor::ImageResult(image);
        */

        // Check, that we already parse maxima output for this plot, and if not, keep it up to this moment
        // If it's true, replace text info result by real plot and set status as Done
        if (m_plotResultIndex != -1)
        {
            replaceResult(m_plotResultIndex, m_plotResult);
            if (status() != Cantor::Expression::Error)
                setStatus(Cantor::Expression::Done);
        }
    }
}
