/*
    Copyright (C) 2016 Volker Krause <vkrause@kde.org>

    This program is free software; you can redistribute it and/or modify it
    under the terms of the GNU Library General Public License as published by
    the Free Software Foundation; either version 2 of the License, or (at your
    option) any later version.

    This program is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Library General Public
    License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

#ifndef KSYNTAXHIGHLIGHTING_THEME_H
#define KSYNTAXHIGHLIGHTING_THEME_H

#include "ksyntaxhighlighting_export.h"

#include <QColor>
#include <QExplicitlySharedDataPointer>
#include <qobjectdefs.h>
#include <QTypeInfo>

namespace KSyntaxHighlighting {

class ThemeData;
class RepositoryPrivate;

/**
 * Color theme definition used for highlighting.
 *
 * @section theme_intro Introduction
 *
 * The Theme provides a full color theme for painting the highlighted text.
 * One Theme is defined either as a *.theme file on disk, or as a file compiled
 * into the SyntaxHighlighting library by using Qt's resource system. Each
 * Theme has a unique name(), including a translatedName() if put into the UI.
 * Themes shipped by default are typically read-only, see isReadOnly().
 *
 * A Theme defines two sets of colors:
 * - Text colors, including foreground and background colors, colors for
 *   selected text, and properties such as bold and italic. These colors are
 *   used e.g. by the SyntaxHighlighter.
 * - Editor colors, including a background color for the entire editor widget,
 *   the line number color, code folding colors, etc.
 *
 * @section theme_text_colors Text Colors and the Class Format
 *
 * The text colors are used for syntax highlighting.
 * // TODO: elaborate more and explain relation to Format class
 *
 * @section theme_editor_colors Editor Colors
 *
 * If you want to use the SyntaxHighlighting framework to write your own text
 * editor, you also need to paint the background of the editing widget. In
 * addition, the editor may support showing line numbers, a folding bar, a
 * highlight for the current text line, and similar features. All these colors
 * are defined in terms of the "editor colors" and accessible by calling
 * editorColor() with the desired enum EditorColorRole.
 *
 * @section theme_access Accessing a Theme
 *
 * All available Theme%s are accessed through the Repository. These themes are
 * typically valid themes. If you create a Theme on your own, isValid() will
 * return @e false, and all colors provided by this Theme are in fact invalid
 * and therefore unusable.
 *
 * @see Format
 * @since 5.28
 */
class KSYNTAXHIGHLIGHTING_EXPORT Theme
{
    Q_GADGET
public:
    /**
     * Default styles that can be referenced from syntax definition XML files.
     * Make sure to choose readable colors with good contrast especially in
     * combination with the EditorColorRole%s.
     */
    enum TextStyle {
        //! Default text style for normal text and source code without
        //! special highlighting.
        Normal = 0,
        //! Text style for language keywords.
        Keyword,
        //! Text style for function definitions and function calls.
        Function,
        //! Text style for variables, if applicable. For instance, variables in
        //! PHP typically start with a '$', so all identifiers following the
        //! pattern $foo are highlighted as variable.
        Variable,
        //! Text style for control flow highlighting, such as @e if, @e then,
        //! @e else, @e return, or @e continue.
        ControlFlow,
        //! Text style for operators such as +, -, *, / and :: etc.
        Operator,
        //! Text style for built-in language classes and functions.
        BuiltIn,
        //! Text style for well-known extensions, such as Qt or boost.
        Extension,
        //! Text style for preprocessor statements.
        Preprocessor,
        //! Text style for attributes of functions or objects, e.g. \@override
        //! in Java, or __declspec(...) and __attribute__((...)) in C++.
        Attribute,
        //! Text style for single characters such as 'a'.
        Char,
        //! Text style for escaped characters in strings, such as "hello\n".
        SpecialChar,
        //! Text style for strings, for instance "hello world".
        String,
        //! Text style for verbatim strings such as HERE docs.
        VerbatimString,
        //! Text style for special strings such as regular expressions in
        //! ECMAScript or the LaTeX math mode.
        SpecialString,
        //! Text style for includes, imports, modules, or LaTeX packages.
        Import,
        //! Text style for data types such as int, char, float etc.
        DataType,
        //! Text style for decimal values.
        DecVal,
        //! Text style for numbers with base other than 10.
        BaseN,
        //! Text style for floating point numbers.
        Float,
        //! Text style for language constants, e.g. True, False, None in Python
        //! or nullptr in C/C++.
        Constant,
        //! Text style for normal comments.
        Comment,
        //! Text style for comments that reflect API documentation, such as
        //! doxygen /** */ comments.
        Documentation,
        //! Text style for annotations in comments, such as \@param in Doxygen
        //! or JavaDoc.
        Annotation,
        //! Text style that refers to variables in a comment, such as after
        //! \@param \<identifier\> in Doxygen or JavaDoc.
        CommentVar,
        //! Text style for region markers, typically defined by BEGIN/END.
        RegionMarker,
        //! Text style for information, such as the keyword \@note in Doxygen.
        Information,
        //! Text style for warnings, such as the keyword \@warning in Doxygen.
        Warning,
        //! Text style for comment specials such as TODO and WARNING in
        //! comments.
        Alert,
        //! Text style indicating wrong syntax.
        Error,
        //! Text style for attributes that do not match any of the other default
        //! styles.
        Others
    };
    Q_ENUM(TextStyle)

    /**
     * Editor color roles, used to paint line numbers, editor background etc.
     * The colors typically should have good contrast with the colors used
     * in the TextStyle%s.
     */
    enum EditorColorRole {
        //! Background color for the editing area.
        BackgroundColor = 0,
        //! Background color for selected text.
        TextSelection,
        //! Background color for the line of the current text cursor.
        CurrentLine,
        //! Background color for matching text while searching.
        SearchHighlight,
        //! Background color for replaced text for a search & replace action.
        ReplaceHighlight,
        //! Background color for matching bracket pairs (including quotes)
        BracketMatching,
        //! Foreground color for visualizing tabs and trailing spaces.
        TabMarker,
        //! Color used to underline spell check errors.
        SpellChecking,
        //! Color used to draw vertical indentation levels, typically a line.
        IndentationLine,
        //! Background color for the icon border.
        IconBorder,
        //! Background colors for code folding regions in the text area, as well
        //! as code folding indicators in the code folding border.
        CodeFolding,
        //! Foreground color for drawing the line numbers. This should have a
        //! good contrast with the IconBorder background color.
        LineNumbers,
        //! Foreground color for drawing the current line number. This should
        //! have a good contrast with the IconBorder background color.
        CurrentLineNumber,
        //! Color used in the icon border to indicate dynamically wrapped lines.
        //! This color should have a good contrast with the IconBorder
        //! background color.
        WordWrapMarker,
        //! Color used to draw a vertical line for marking changed lines.
        ModifiedLines,
        //! Color used to draw a vertical line for marking saved lines.
        SavedLines,
        //! Line color used to draw separator lines, e.g. at column 80 in the
        //! text editor area.
        Separator,
        //! Background color for bookmarks.
        MarkBookmark,
        //! Background color for active breakpoints.
        MarkBreakpointActive,
        //! Background color for a reached breakpoint.
        MarkBreakpointReached,
        //! Background color for inactive (disabled) breakpoints.
        MarkBreakpointDisabled,
        //! Background color for marking the current execution position.
        MarkExecution,
        //! Background color for general warning marks.
        MarkWarning,
        //! Background color for general error marks.
        MarkError,
        //! Background color for text templates (snippets).
        TemplateBackground,
        //! Background color for all editable placeholders in text templates.
        TemplatePlaceholder,
        //! Background color for the currently active placeholder in text
        //! templates.
        TemplateFocusedPlaceholder,
        //! Background color for read-only placeholders in text templates.
        TemplateReadOnlyPlaceholder
    };
    Q_ENUM(EditorColorRole)

    /**
     * Default constructor, creating an invalid Theme, see isValid().
     */
    Theme();

    /**
     * Copy constructor, sharing the Theme data with @p copy.
     */
    Theme(const Theme &copy);

    /**
     * Destructor.
     */
    ~Theme();

    /**
     * Assignment operator, sharing the Theme data with @p other.
     */
    Theme &operator=(const Theme &other);

    /**
     * Returns @c true if this is a valid Theme.
     * If the theme is invalid, none of the returned colors are well-defined.
     */
    bool isValid() const;

    /**
     * Returns the unique name of this Theme.
     * @see translatedName()
     */
    QString name() const;

    /**
     * Returns the translated name of this Theme. The translated name can be
     * used in the user interface.
     */
    QString translatedName() const;

    /**
     * Returns @c true if this Theme is read-only.
     *
     * A Theme is read-only, if the filePath() points to a non-writable file.
     * This is typically the case for Themes that are compiled into the executable
     * as resource file, as well as for theme files that are installed in read-only
     * system locations (e.g. /usr/share/).
     */
    bool isReadOnly() const;

    /**
     * Returns the full path and file name to this Theme.
     * Themes from the Qt resource return the Qt resource path.
     * Themes from disk return the local path.
     *
     * If the theme is invalid (isValid()), an empty string is returned.
     */
    QString filePath() const;

    /**
     * Returns the text color to be used for @p style.
     * @c 0 is returned for styles that do not specify a text color,
     * use the default text color in that case.
     */
    QRgb textColor(TextStyle style) const;

    /**
     * Returns the selected text color to be used for @p style.
     * @c 0 is returned for styles that do not specify a selected text color,
     * use the default textColor() in that case.
     */
    QRgb selectedTextColor(TextStyle style) const;

    /**
     * Returns the background color to be used for @p style.
     * @c 0 is returned for styles that do not specify a background color,
     * use the default background color in that case.
     */
    QRgb backgroundColor(TextStyle style) const;

    /**
     * Returns the background color to be used for selected text for @p style.
     * @c 0 is returned for styles that do not specify a background color,
     * use the default backgroundColor() in that case.
     */
    QRgb selectedBackgroundColor(TextStyle style) const;

    /**
     * Returns whether the given style should be shown in bold.
     */
    bool isBold(TextStyle style) const;

    /**
     * Returns whether the given style should be shown in italic.
     */
    bool isItalic(TextStyle style) const;

    /**
     * Returns whether the given style should be shown underlined.
     */
    bool isUnderline(TextStyle style) const;

    /**
     * Returns whether the given style should be shown struck through.
     */
    bool isStrikeThrough(TextStyle style) const;

public:
    /**
     * Returns the editor color for the requested @p role.
     */
    QRgb editorColor(EditorColorRole role) const;

private:
    /**
     * Constructor taking a shared ThemeData instance.
     */
    explicit Theme(ThemeData* data);
    friend class RepositoryPrivate;
    friend class ThemeData;

private:
    /**
     * Shared data holder.
     */
    QExplicitlySharedDataPointer<ThemeData> m_data;
};

}

Q_DECLARE_TYPEINFO(KSyntaxHighlighting::Theme, Q_MOVABLE_TYPE);

#endif // KSYNTAXHIGHLIGHTING_THEME_H
