/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the Qt Designer of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:GPL-EXCEPT$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3 as published by the Free Software
** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
** included in the packaging of this file. Please review the following
** information to ensure the GNU General Public License requirements will
** be met: https://www.gnu.org/licenses/gpl-3.0.html.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "textpropertyeditor_p.h"
#include "propertylineedit_p.h"
#include "stylesheeteditor_p.h"

#include <QtWidgets/qlineedit.h>
#include <QtGui/qvalidator.h>
#include <QtGui/qevent.h>
#include <QtWidgets/qcompleter.h>
#include <QtWidgets/qabstractitemview.h>
#include <QtCore/qregularexpression.h>
#include <QtCore/qurl.h>
#include <QtCore/qfile.h>
#include <QtCore/qdebug.h>

QT_BEGIN_NAMESPACE

namespace {
    const QChar NewLineChar(QLatin1Char('\n'));
    const QLatin1String EscapedNewLine("\\n");

    // A validator that replaces offending strings
    class ReplacementValidator : public QValidator {
    public:
        ReplacementValidator (QObject * parent,
                              const QString &offending,
                              const QString &replacement);
        void fixup ( QString & input ) const override;
        State validate ( QString & input, int &pos) const override;
    private:
        const QString m_offending;
        const QString m_replacement;
    };

    ReplacementValidator::ReplacementValidator (QObject * parent,
                                        const QString &offending,
                                        const QString &replacement) :
      QValidator(parent ),
      m_offending(offending),
      m_replacement(replacement)
    {
    }

    void ReplacementValidator::fixup ( QString & input ) const {
        input.replace(m_offending, m_replacement);
    }

    QValidator::State ReplacementValidator::validate ( QString & input, int &/* pos */) const {
        fixup (input);
        return Acceptable;
    }

    // A validator for style sheets. Does newline handling and validates sheets.
    class StyleSheetValidator : public ReplacementValidator {
    public:
        StyleSheetValidator (QObject * parent);
        State validate(QString & input, int &pos) const override;
    };

    StyleSheetValidator::StyleSheetValidator (QObject * parent) :
       ReplacementValidator(parent, NewLineChar, EscapedNewLine)
    {
    }

    QValidator::State StyleSheetValidator::validate ( QString & input, int &pos) const
    {
        // base class
        const State state = ReplacementValidator:: validate(input, pos);
        if (state != Acceptable)
            return state;
        // now check style sheet, create string with newlines
        const QString styleSheet = qdesigner_internal::TextPropertyEditor::editorStringToString(input, qdesigner_internal::ValidationStyleSheet);
        const bool valid = qdesigner_internal::StyleSheetEditorDialog::isStyleSheetValid(styleSheet);
        return valid ? Acceptable : Intermediate;
    }

    // A validator for URLs based on QUrl. Enforces complete protocol
    // specification with a completer (adds a trailing slash)
    class UrlValidator : public QValidator {
    public:
        UrlValidator(QCompleter *completer, QObject *parent);

        State validate(QString &input, int &pos) const override;
        void fixup(QString &input) const override;
    private:
        QUrl guessUrlFromString(const QString &string) const;
        QCompleter *m_completer;
    };

    UrlValidator::UrlValidator(QCompleter *completer, QObject *parent) :
        QValidator(parent),
        m_completer(completer)
    {
    }

    QValidator::State UrlValidator::validate(QString &input, int &pos) const
    {
        Q_UNUSED(pos);

        if (input.isEmpty())
            return Acceptable;

        const QUrl url(input, QUrl::StrictMode);

        if (!url.isValid() || url.isEmpty())
            return Intermediate;

        if (url.scheme().isEmpty())
            return Intermediate;

        if (url.host().isEmpty() && url.path().isEmpty())
            return Intermediate;

        return Acceptable;
    }

    void UrlValidator::fixup(QString &input) const
    {
        // Don't try to fixup if the user is busy selecting a completion proposal
        if (const QAbstractItemView *iv = m_completer->popup()) {
            if (iv->isVisible())
                return;
        }

        input = guessUrlFromString(input).toString();
    }

    QUrl UrlValidator::guessUrlFromString(const QString &string) const
    {
        const QString urlStr = string.trimmed();
        const QRegularExpression qualifiedUrl(QStringLiteral("^[a-zA-Z]+\\:.*$"));
        Q_ASSERT(qualifiedUrl.isValid());

        // Check if it looks like a qualified URL. Try parsing it and see.
        const bool hasSchema = qualifiedUrl.match(urlStr).hasMatch();
        if (hasSchema) {
            const QUrl url(urlStr, QUrl::TolerantMode);
            if (url.isValid())
                return url;
        }

        // Might be a Qt resource
        if (string.startsWith(QStringLiteral(":/")))
            return QUrl(QStringLiteral("qrc") + string);

        // Might be a file.
        if (QFile::exists(urlStr))
            return QUrl::fromLocalFile(urlStr);

        // Might be a short url - try to detect the schema.
        if (!hasSchema) {
            const int dotIndex = urlStr.indexOf(QLatin1Char('.'));
            if (dotIndex != -1) {
                const QString prefix = urlStr.left(dotIndex).toLower();
                QString urlString;
                if (prefix == QStringLiteral("ftp"))
                    urlString += prefix;
                else
                    urlString += QStringLiteral("http");
                urlString += QStringLiteral("://");
                urlString += urlStr;
                const QUrl url(urlString, QUrl::TolerantMode);
                if (url.isValid())
                    return url;
            }
        }

        // Fall back to QUrl's own tolerant parser.
        return QUrl(string, QUrl::TolerantMode);
    }
}

namespace qdesigner_internal {
    // TextPropertyEditor
    TextPropertyEditor::TextPropertyEditor(QWidget *parent,
                                           EmbeddingMode embeddingMode,
                                           TextPropertyValidationMode validationMode) :
        QWidget(parent),
        m_lineEdit(new PropertyLineEdit(this))
    {
        switch (embeddingMode) {
        case EmbeddingNone:
            break;
        case EmbeddingTreeView:
            m_lineEdit->setFrame(false);
            break;
        case EmbeddingInPlace:
            m_lineEdit->setFrame(false);
            Q_ASSERT(parent);
            m_lineEdit->setBackgroundRole(parent->backgroundRole());
            break;
        }

        setFocusProxy(m_lineEdit);

        connect(m_lineEdit,&QLineEdit::editingFinished, this, &TextPropertyEditor::editingFinished);
        connect(m_lineEdit,&QLineEdit::returnPressed, this, &TextPropertyEditor::slotEditingFinished);
        connect(m_lineEdit,&QLineEdit::textChanged, this, &TextPropertyEditor::slotTextChanged);
        connect(m_lineEdit,&QLineEdit::textEdited, this, &TextPropertyEditor::slotTextEdited);

        setTextPropertyValidationMode(validationMode);
    }

    void TextPropertyEditor::setTextPropertyValidationMode(TextPropertyValidationMode vm) {
        m_validationMode = vm;
        m_lineEdit->setWantNewLine(multiLine(m_validationMode));
        switch (m_validationMode) {
        case ValidationStyleSheet:
            m_lineEdit->setValidator(new  StyleSheetValidator(m_lineEdit));
            m_lineEdit->setCompleter(nullptr);
            break;
        case ValidationMultiLine:
        case ValidationRichText:
            // Set a  validator that replaces newline characters by literal "\\n".
            // While it is not possible to actually type a newline  characters,
            // it can be pasted into the line edit.
            m_lineEdit->setValidator(new ReplacementValidator(m_lineEdit, NewLineChar, EscapedNewLine));
            m_lineEdit->setCompleter(nullptr);
            break;
        case ValidationSingleLine:
            // Set a  validator that replaces newline characters by a blank.
            m_lineEdit->setValidator(new ReplacementValidator(m_lineEdit, NewLineChar, QString(QLatin1Char(' '))));
             m_lineEdit->setCompleter(nullptr);
            break;
        case ValidationObjectName:
            setRegularExpressionValidator(QStringLiteral("^[_a-zA-Z][_a-zA-Z0-9]{1,1023}$"));
             m_lineEdit->setCompleter(nullptr);
             break;
        case ValidationObjectNameScope:
            setRegularExpressionValidator(QStringLiteral("^[_a-zA-Z:][_a-zA-Z0-9:]{1,1023}$"));
            m_lineEdit->setCompleter(nullptr);
            break;
        case ValidationURL: {
            static QStringList urlCompletions;
            if (urlCompletions.isEmpty()) {
                urlCompletions.push_back(QStringLiteral("about:blank"));
                urlCompletions.push_back(QStringLiteral("http://"));
                urlCompletions.push_back(QStringLiteral("http://www."));
                urlCompletions.push_back(QStringLiteral("http://qt.io"));
                urlCompletions.push_back(QStringLiteral("file://"));
                urlCompletions.push_back(QStringLiteral("ftp://"));
                urlCompletions.push_back(QStringLiteral("data:"));
                urlCompletions.push_back(QStringLiteral("data:text/html,"));
                urlCompletions.push_back(QStringLiteral("qrc:/"));
            }
            QCompleter *completer = new QCompleter(urlCompletions, m_lineEdit);
            m_lineEdit->setCompleter(completer);
            m_lineEdit->setValidator(new UrlValidator(completer, m_lineEdit));
        }
            break;
        }

        setFocusProxy(m_lineEdit);
        setText(m_cachedText);
        markIntermediateState();
    }

    void TextPropertyEditor::setRegularExpressionValidator(const QString &pattern)
    {
        QRegularExpression regExp(pattern);
        Q_ASSERT(regExp.isValid());
        m_lineEdit->setValidator(new QRegularExpressionValidator(regExp, m_lineEdit));
    }

    QString TextPropertyEditor::text() const
    {
        return m_cachedText;
    }

    void TextPropertyEditor::markIntermediateState()
    {
        if (m_lineEdit->hasAcceptableInput()) {
            m_lineEdit->setPalette(QPalette());
        } else {
            QPalette palette = m_lineEdit->palette();
            palette.setColor(QPalette::Active, QPalette::Text, Qt::red);
            m_lineEdit->setPalette(palette);
        }

    }

    void TextPropertyEditor::setText(const QString &text)
    {
        m_cachedText = text;
        m_lineEdit->setText(stringToEditorString(text, m_validationMode));
        markIntermediateState();
        m_textEdited = false;
    }

    void TextPropertyEditor::slotTextEdited()
    {
        m_textEdited = true;
    }

    void  TextPropertyEditor::slotTextChanged(const QString &text) {
        m_cachedText = editorStringToString(text, m_validationMode);
        markIntermediateState();
        if (m_updateMode == UpdateAsYouType)
            emit textChanged(m_cachedText);
    }

    void TextPropertyEditor::slotEditingFinished()
    {
        if (m_updateMode == UpdateOnFinished && m_textEdited) {
            emit textChanged(m_cachedText);
            m_textEdited = false;
        }
    }

    void TextPropertyEditor::selectAll() {
        m_lineEdit->selectAll();
    }

    void TextPropertyEditor::clear() {
        m_lineEdit->clear();
    }

    void TextPropertyEditor::setAlignment(Qt::Alignment alignment) {
        m_lineEdit->setAlignment(alignment);
    }

    void TextPropertyEditor::installEventFilter(QObject *filterObject)
    {
        if (m_lineEdit)
            m_lineEdit->installEventFilter(filterObject);
    }

    void TextPropertyEditor::resizeEvent ( QResizeEvent * event ) {
        m_lineEdit->resize( event->size());
    }

    QSize TextPropertyEditor::sizeHint () const {
        return  m_lineEdit->sizeHint ();
    }

    QSize TextPropertyEditor::minimumSizeHint () const {
        return  m_lineEdit->minimumSizeHint ();
    }

    // Returns whether newline characters are valid in validationMode.
    bool TextPropertyEditor::multiLine(TextPropertyValidationMode validationMode) {
        return validationMode == ValidationMultiLine || validationMode == ValidationStyleSheet || validationMode == ValidationRichText;
    }

    // Replace newline characters literal "\n"  for inline editing in mode ValidationMultiLine
    QString TextPropertyEditor::stringToEditorString(const QString &s, TextPropertyValidationMode  validationMode) {
        if (s.isEmpty() || !multiLine(validationMode))
            return s;

        QString rc(s);
        // protect backslashes
        rc.replace(QLatin1Char('\\'), QStringLiteral("\\\\"));
        // escape newlines
        rc.replace(NewLineChar, QString(EscapedNewLine));
        return rc;

    }

    // Replace literal "\n"  by actual new lines for inline editing in mode ValidationMultiLine
    // Note: As the properties are updated while the user types, it is important
    // that trailing slashes ('bla\') are not deleted nor ignored, else this will
    // cause jumping of the  cursor
    QString  TextPropertyEditor::editorStringToString(const QString &s, TextPropertyValidationMode  validationMode) {
        if (s.isEmpty() || !multiLine(validationMode))
            return s;

        QString rc(s);
        for (int pos = 0; (pos = rc.indexOf(QLatin1Char('\\'),pos)) >= 0 ; ) {
            // found an escaped character. If not a newline or at end of string, leave as is, else insert '\n'
            const int nextpos = pos + 1;
            if (nextpos  >= rc.length())  // trailing '\\'
                 break;
            // Escaped NewLine
            if (rc.at(nextpos) ==  QChar(QLatin1Char('n')))
                 rc[nextpos] =  NewLineChar;
            // Remove escape, go past escaped
            rc.remove(pos,1);
            pos++;
        }
        return rc;
    }

    bool TextPropertyEditor::hasAcceptableInput() const {
        return m_lineEdit->hasAcceptableInput();
    }
}

QT_END_NAMESPACE