#include "WedgeCommands.h"
#include <QDate>
#include <QJSEngine>
#include <QJSValue>
#include <QMap>
#include <QRegularExpression>
#include <QTextBlock>
#include <QTextCursor>
#include <QTextEdit>
#include <QtGlobal>

namespace WedgeCommands {

QString otcDateResult(int day, QString mon) {
    static QMap<QString, int> months = {
        {"jan", 1}, {"feb", 2}, {"mar", 3}, {"apr", 4}, {"may", 5}, {"jun", 6},
        {"jul", 7}, {"aug", 8}, {"sep", 9}, {"oct", 10}, {"nov", 11}, {"dec", 12}
    };
    int m = months.value(mon.toLower(), 0);
    if (m == 0) return "";
    QDate now = QDate::currentDate();
    QDate target(now.year(), m, day);
    if (target < now) target = target.addYears(1);
    QDate otcStart(target.year(), 3, 20);
    if (target < otcStart) otcStart = otcStart.addYears(-1);
    return QString("(%1)=%2").arg(otcStart.daysTo(target) + 1).arg(now.daysTo(target));
}

Result apply(QTextEdit *editor, QJSEngine &engine, int key) {
    Result r;
    if (!editor) return r;

    QTextCursor cursor = editor->textCursor();
    QString lineText = cursor.block().text().left(cursor.positionInBlock());

    static QRegularExpression mathRegex("(?<=\\s|^|=)((\\d+(\\.\\d+)?%?[\\+\\-\\*\\/])+\\d+(\\.\\d+)?%?)=$");
    static QRegularExpression dateRegex("(?<=\\s|^)(\\d{1,2})([a-zA-Z]{3})\\(\\)=$");
    static QRegularExpression listRegex("^(\\s*)(\\d+)\\.\\s");
    static QRegularExpression hrRegex("(?<=\\s|^)hr\\((\\d+)\\)$");
    static QRegularExpression dashRegex("(?<=\\s|^)dash\\((\\d+)\\)$");

    auto mMatch = mathRegex.match(lineText);
    if (mMatch.hasMatch()) {
        QString expression = mMatch.captured(1);

        static QRegularExpression percentRegex("([\\d\\.]+)\\s*([\\+\\-\\*\\/])\\s*([\\d\\.]+)%");

        while (expression.contains('%')) {
            QRegularExpressionMatch pMatch = percentRegex.match(expression);
            if (!pMatch.hasMatch()) break;

            QString base = pMatch.captured(1);
            QString op = pMatch.captured(2);
            QString percentVal = pMatch.captured(3);

            QString replacement = QString("%1 %2 (%1 * (%3 / 100))").arg(base, op, percentVal);
            expression.replace(pMatch.capturedStart(), pMatch.capturedLength(), replacement);
        }

        QJSValue result = engine.evaluate(expression);
        if (!result.isError()) {
            QString resStr = QString::number(result.toNumber(), 'f', 2);
            if (resStr.contains('.')) {
                while (resStr.endsWith('0')) resStr.chop(1);
                if (resStr.endsWith('.')) resStr.chop(1);
            }
            editor->blockSignals(true);
            cursor.insertText(resStr);
            editor->blockSignals(false);
            r.changed = true;
        }
        r.consumed = (key == Qt::Key_Space);
        return r;
    }

    auto dMatch = dateRegex.match(lineText);
    if (dMatch.hasMatch()) {
        QString res = otcDateResult(dMatch.captured(1).toInt(), dMatch.captured(2));
        if (!res.isEmpty()) {
            editor->blockSignals(true);
            cursor.movePosition(QTextCursor::Left, QTextCursor::KeepAnchor, 3);
            cursor.insertText(res);
            editor->blockSignals(false);
            r.changed = true;
        }
        r.consumed = (key == Qt::Key_Space);
        return r;
    }

    auto hMatch = hrRegex.match(lineText);
    if (hMatch.hasMatch()) {
        int count = hMatch.captured(1).toInt();
        if (count > 0) {
            QString hrline = QString("\u2014").repeated(qMin(count, 100));
            editor->blockSignals(true);
            cursor.movePosition(QTextCursor::Left, QTextCursor::KeepAnchor, hMatch.capturedLength());
            cursor.insertText(hrline);
            editor->blockSignals(false);
            r.changed = true;
        }
        r.consumed = (key == Qt::Key_Space);
        return r;
    }

    auto emMatch = dashRegex.match(lineText);
    if (emMatch.hasMatch()) {
        int counts = emMatch.captured(1).toInt();
        if (counts > 0) {
            QString dashes = QString("\u2014 ").repeated(qMin(counts, 100));
            editor->blockSignals(true);
            cursor.movePosition(QTextCursor::Left, QTextCursor::KeepAnchor, emMatch.capturedLength());
            cursor.insertText(dashes);
            editor->blockSignals(false);
            r.changed = true;
        }
        r.consumed = (key == Qt::Key_Space);
        return r;
    }

    if (key != Qt::Key_Space) {
        auto lMatch = listRegex.match(lineText);
        if (lMatch.hasMatch()) {
            QString ws = lMatch.captured(1);
            int num = lMatch.captured(2).toInt();
            QString prefix = "\n" + ws + QString::number(num + 1) + ". ";
            editor->blockSignals(true);
            cursor.beginEditBlock();
            cursor.insertText(prefix);
            QTextBlock nextBlock = cursor.block().next();
            int nextExpected = num + 1;
            int i = 0;
            while (nextBlock.isValid()) {
                auto m = listRegex.match(nextBlock.text());
                if (m.hasMatch() && m.captured(1) == ws && m.captured(2).toInt() == nextExpected) {
                    int foundNum = m.captured(2).toInt();
                    QTextCursor nextCursor(nextBlock);
                    nextCursor.movePosition(QTextCursor::NextCharacter, QTextCursor::KeepAnchor, m.capturedLength());
                    nextCursor.insertText(m.captured(1) + QString::number(foundNum + 1) + ". ");
                    nextExpected++;
                } else if (i > 0) break;
                nextBlock = nextBlock.next(); i++;
            }
            cursor.endEditBlock();
            editor->blockSignals(false);
            r.changed = true;
            r.consumed = true;
            return r;
        }
        static QRegularExpression indentRegex("^(\\s+)");
        auto iMatch = indentRegex.match(lineText);
        if (iMatch.hasMatch()) {
            QString indent = "\n" + iMatch.captured(1);
            editor->blockSignals(true);
            cursor.insertText(indent);
            editor->blockSignals(false);
            r.changed = true;
            r.consumed = true;
            return r;
        }
    }
    return r;
}

}