/* Copyright (C) 2016 by ETH Zürich
 * Software engineering by Intevation GmbH
 *
 * This file is Free Software under the GNU GPL (v>=2)
 * and comes with ABSOLUTELY NO WARRANTY!
 * See LICENSE.txt for details.
 */

#include "converter.h"
#include <QDebug>
#include <QRegularExpression>
#include <QRegularExpressionMatch>

#include "xlsxdocument.h"
#include "xlsxconditionalformatting.h"

#include "constants.h"

QTXLSX_USE_NAMESPACE

Converter::Converter(const QString &input, const QString &output,
                     ConvertFormat fmt, const QString &title):
    QThread(Q_NULLPTR),
    mInput(input),
    mOutput(output),
    mFmt(fmt),
    mTitle(title)
{
    mTitleFmt.setFontUnderline(Format::FontUnderlineSingle);
    mTitleFmt.setFontSize(18);
    mTitleFmt.setFontName("Calibri");
    mTitleFmt.setFontBold(true);
    mTitleFmt.setVerticalAlignment(Format::AlignTop);

    mQuestionFmt.setFontSize(11);
    mQuestionFmt.setFontName("Calibri");
    mQuestionFmt.setFontBold(true);
    mQuestionFmt.setTopBorderStyle(Format::BorderThin);
    mQuestionFmt.setBottomBorderStyle(Format::BorderThin);
    mQuestionFmt.setTextWarp(true);

    mAnswerChoiceFmt.setFontSize(11);
    mAnswerChoiceFmt.setFontName("Calibri");
    mAnswerChoiceFmt.setHorizontalAlignment(Format::AlignRight);
    mAnswerChoiceFmt.setTextWarp(true);

    mChoiceTextFmt = mAnswerChoiceFmt;
    mChoiceTextFmt.setVerticalAlignment(Format::AlignVCenter);

    mFreeTextFmt = mQuestionFmt;
    mFreeTextFmt.setFontBold(false);

    mAnswerTextFmt = mQuestionFmt;
    mAnswerTextFmt.setVerticalAlignment(Format::AlignVCenter);
    mAnswerTextFmt.setHorizontalAlignment(Format::AlignLeft);
}

void Converter::run()
{
    QFile infile;

    if (mInput.isEmpty()) {
        if (!infile.open(stdin, QIODevice::ReadOnly)) {
            mErrors << tr("Failed to open standard input and no input file provided.");
            return;
        }
    } else {
        infile.setFileName(mInput);
        if (!infile.open(QIODevice::ReadOnly)) {
            mErrors << tr("Failed to open %1 for reading.").arg(mInput);
            return;
        }
    }
    QTextStream instream(&infile);

    QFile outfile;
    if (mOutput.isEmpty()) {
        if (!outfile.open(stdout, QIODevice::WriteOnly)) {
            mErrors << tr("Failed to open standard output and no output file provided.");
            return;
        }
    } else {
        outfile.setFileName(mOutput);
        if (!outfile.open(QIODevice::WriteOnly)) {
            mErrors << tr("Failed to open %1 for writing.").arg(mOutput);
            return;
        }
    }
    convertToXSLX(instream, outfile);
}

void Converter::convertToXSLX(QTextStream& instream, QFile &output)
{
    Document xlsx;

    ConditionalFormatting bars;

    bars.addDataBarRule(QColor(0xFF, 0x99, 0x33), ConditionalFormatting::VOT_Num,
                        "0", ConditionalFormatting::VOT_Num, "100", false);

    const double colWidth[] = COLUMN_WIDTHS;
    double sum = 0;
    for (int i = 1; i <= COLUMN_CNT; i++) {
        xlsx.setColumnWidth(i, colWidth[i-1]);
        sum += colWidth[i-1];
    }

    /* For the merged cell wordwrap trick. */
    xlsx.setColumnWidth(26, sum - 1);
    xlsx.setColumnHidden(26, true);

    int row = 1;
    if (!mTitle.isEmpty()) {
        // Set the title of the Questionaire
        xlsx.write(row++, 1, mTitle, mTitleFmt);
        xlsx.mergeCells("A1:C1");
        xlsx.setRowHeight(1, TITLE_ROW_HEIGHT);
    }

    const QString input = instream.readAll();

    QRegularExpression questionEx(QUESTION_PATTERN);
    QRegularExpression choiceEx(CHOICE_PATTERN);
    QRegularExpression freetxtEx (FREETXT_PATTERN);

    QRegularExpressionMatch match = questionEx.match(input);
    bool foundSomething = false;
    int cursor = match.capturedEnd();
    while (match.hasMatch() && cursor != -1) {
        /* We've matched a question pattern. With the answer
           line */
        if (!match.lastCapturedIndex() == 2) {
            /* Should not happen without misconfiguration. */
            mErrors << "Internal parser error.";
            return;
        }
        foundSomething = true;
        const QString question = match.captured(1).trimmed();
        const QString answerLine = match.captured(2).trimmed();
        xlsx.write(row, 2, QString(" "), mQuestionFmt);
        xlsx.write(row, 3, QString(" "), mQuestionFmt);
        xlsx.write(row++, 1, question, mQuestionFmt);

        if (answerLine == QStringLiteral(CHOICE_IDENTIFIER)) {
            QRegularExpressionMatch choiceMatch = choiceEx.match(input, cursor);
            xlsx.setRowHeight(row, CHOICE_ROW_HEIGHT);
            xlsx.write(row++, 1, tr("Answer"), mAnswerChoiceFmt);
            int firstChoiceRow = row;
            int lastChoiceRow = row;
            while (choiceMatch.hasMatch() && choiceMatch.capturedStart() == cursor + 1) {
                /* We use the cursor here to keep track of the state. Only if an answer
                   follows immediately behind the last answer we treat it as valid as
                   otherwise we can't figure out when the next question begins. */
                cursor = choiceMatch.capturedEnd();

                /* Write the values */
                xlsx.write(row, 1, choiceMatch.captured(1), mChoiceTextFmt);
                bool ok;
                double percent = choiceMatch.captured(3).toDouble(&ok);
                if (!ok) {
                    mErrors << "Unparsable number in string: " + choiceMatch.captured();
                }
                xlsx.write(row, 2, percent);
                xlsx.write(row, 3, tr("%1% | %2 Number of votes").
                           arg(choiceMatch.captured(3)).arg(choiceMatch.captured(2)),
                           mChoiceVotesFmt);
                xlsx.setRowHeight(row, CHOICE_ROW_HEIGHT);
                /* As long as we can match a choice which is either before the next question
                   or before the end of the document */
                choiceMatch = choiceEx.match(input, cursor);
                row++;
                lastChoiceRow++;
            }
            bars.addRange(QString("B%1:B%2").arg(firstChoiceRow).arg(lastChoiceRow));
        } else if (answerLine == QStringLiteral(TEXT_IDENTIFIER)) {
            QRegularExpressionMatch textMatch = freetxtEx.match(input, cursor);
            xlsx.setRowHeight(row, CHOICE_ROW_HEIGHT);
            xlsx.write(row++, 1, tr("Answer"), mAnswerTextFmt);
            while (textMatch.hasMatch()) {
                if (textMatch.capturedStart() != cursor + 1) {
                    /* The format allows unescaped quotes in the text.
                       This makes a workaround neccessary. If we have
                       an Unquoted string between the next quoted string
                       and that Unquoted string is before the next question
                       we append the unquoted string and the next quoted string
                       with Quotes in the Row.*/
                    QRegularExpressionMatch nextQuestion = questionEx.match(input, cursor);
                    if (nextQuestion.hasMatch() &&
                        nextQuestion.capturedStart() < textMatch.capturedEnd()) {
                        /* The next question comes before the textMatch so we really have
                           a new question. */
                        break;
                    }
                    const QString lastRow = xlsx.read(row - 1, 26).toString();
                    int unquotedLen = textMatch.capturedStart() - cursor;
                    const QString unquoted = input.mid(cursor, unquotedLen);
                    qDebug() << "Found inner quoted string: " << unquoted;
                    /* Now combine */
                    const QString combined = QString("%1\"%2\"%3").arg(lastRow).
                                                                   arg(unquoted).
                                                                   arg(textMatch.captured(1).trimmed());
                    qDebug() << "Last row: " << lastRow;
                    qDebug() << "Next Question is at: " << nextQuestion.capturedStart();
                    qDebug() << "Text match is: " << textMatch.captured(1).trimmed();
                    qDebug() << "cursor is at: " << cursor;
                    qDebug() << "text match starts at: " << textMatch.capturedStart();
                    xlsx.write(row - 1, 26, combined, mFreeTextFmt);
                    cursor = textMatch.capturedEnd();
                    textMatch = freetxtEx.match(input, cursor);
                    continue;
                }
                cursor = textMatch.capturedEnd();

                QString text = textMatch.captured(1).trimmed();
                qDebug() << "Found free text: " << text;

                /* Merge the cells */
                xlsx.mergeCells(QString("A%1:C%1").arg(row), mFreeTextFmt);

                /* Merged cells ignore wordwrap the following trick is based on:
                   http://excel.tips.net/T003207_Automatic_Row_Height_For_Merged_Cells_with_Text_Wrap.html
                */
                /* Write the values */
                xlsx.write(QString("Z%1").arg(row), text, mFreeTextFmt);
                xlsx.write(row, 1, QString("=Z%1").arg(row));
                row++;
                textMatch = freetxtEx.match(input, cursor);
            }
        }
        /* Insert Empty row. */
        xlsx.setRowHeight(row++, CHOICE_ROW_HEIGHT);
        match = questionEx.match(input, cursor);
        cursor = match.capturedEnd();
    }
    xlsx.addConditionalFormatting(bars);

    if (!foundSomething) {
        mErrors << tr("Failed to parse input document.");
    }

    if (!xlsx.saveAs(&output)) {
        mErrors << tr("Saving the XLSX document failed.");
        return;
    }
}