/***************************************************************************
 *   Copyright (C) 2005-2018 by the Quassel Project                        *
 *   devel@quassel-irc.org                                                 *
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) version 3.                                           *
 *                                                                         *
 *   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 General Public License for more details.                          *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this program; if not, write to the                         *
 *   Free Software Foundation, Inc.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.         *
 ***************************************************************************/

#pragma once

#include <utility>
#include <vector>

#include <QColor>
#include <QDataStream>
#include <QFontMetricsF>
#include <QHash>
#include <QIcon>
#include <QTextCharFormat>
#include <QTextLayout>
#include <QPalette>
#include <QVector>

#include "bufferinfo.h"
#include "message.h"
#include "networkmodel.h"
#include "settings.h"

class UiStyle : public QObject
{
    Q_OBJECT
    Q_ENUMS(SenderPrefixModes)

public:
    UiStyle(QObject *parent = 0);
    virtual ~UiStyle();

    //! This enumerates the possible formats a text element may have. */
    /** These formats are ordered on increasing importance, in cases where a given property is specified
     *  by multiple active formats.
     *  \NOTE: Do not change/add values here without also adapting the relevant
     *         methods in this class (in particular mergedFormat())!
     *         Also, we _do_ rely on certain properties of these values in styleString() and friends!
     */
    enum class FormatType : quint32 {
        Base            = 0x00000000,
        Invalid         = 0xffffffff,

        // Message Formats (mutually exclusive!)
        PlainMsg        = 0x00000001,
        NoticeMsg       = 0x00000002,
        ActionMsg       = 0x00000003,
        NickMsg         = 0x00000004,
        ModeMsg         = 0x00000005,
        JoinMsg         = 0x00000006,
        PartMsg         = 0x00000007,
        QuitMsg         = 0x00000008,
        KickMsg         = 0x00000009,
        KillMsg         = 0x0000000a,
        ServerMsg       = 0x0000000b,
        InfoMsg         = 0x0000000c,
        ErrorMsg        = 0x0000000d,
        DayChangeMsg    = 0x0000000e,
        TopicMsg        = 0x0000000f,
        NetsplitJoinMsg = 0x00000010,
        NetsplitQuitMsg = 0x00000020,
        InviteMsg       = 0x00000030,

        // Standard Formats
        Bold            = 0x00000100,
        Italic          = 0x00000200,
        Underline       = 0x00000400,
        Strikethrough   = 0x00000800,

        // Individual parts of a message
        Timestamp       = 0x00001000,
        Sender          = 0x00002000,
        Contents        = 0x00004000,
        Nick            = 0x00008000,
        Hostmask        = 0x00010000,
        ChannelName     = 0x00020000,
        ModeFlags       = 0x00040000,

        // URL is special, we want that to take precedence over the rest...
        Url             = 0x00080000

                          // mIRC Colors - we assume those to be present only in plain contents
                          // foreground: 0x0.400000
                          // background: 0x.0800000
    };

    enum class MessageLabel : quint32 {
        None            = 0x00000000,
        OwnMsg          = 0x00000001,
        Highlight       = 0x00000002,
        Selected        = 0x00000004,
        Hovered         = 0x00000008,
        Last            = Hovered
    };

    enum class ItemFormatType : quint32 {
        None              = 0x00000000,

        BufferViewItem    = 0x00000001,
        NickViewItem      = 0x00000002,

        NetworkItem       = 0x00000010,
        ChannelBufferItem = 0x00000020,
        QueryBufferItem   = 0x00000040,
        IrcUserItem       = 0x00000080,
        UserCategoryItem  = 0x00000100,

        InactiveBuffer    = 0x00001000,
        ActiveBuffer      = 0x00002000,
        UnreadBuffer      = 0x00004000,
        HighlightedBuffer = 0x00008000,
        UserAway          = 0x00010000,

        Invalid           = 0xffffffff
    };

    enum class FormatProperty {
        AllowForegroundOverride = QTextFormat::UserProperty,
        AllowBackgroundOverride
    };

    enum class ColorRole {
        MarkerLine,
        // Sender colors (16 + self)
        // These aren't used directly to avoid having storing all of the sender color options in the
        // rendering routine of each item.  Also, I couldn't figure out how to do that.
        // It would be nice to have the UseSenderColors preference also toggle sender colors set by
        // themes, so hopefully this can be extended in the future.
        // Furthermore, using this palette directly would mean separate sets of colors couldn't be
        // used for different message types.
        SenderColorSelf,
        SenderColor00,
        SenderColor01,
        SenderColor02,
        SenderColor03,
        SenderColor04,
        SenderColor05,
        SenderColor06,
        SenderColor07,
        SenderColor08,
        SenderColor09,
        SenderColor0a,
        SenderColor0b,
        SenderColor0c,
        SenderColor0d,
        SenderColor0e,
        SenderColor0f,
        NumRoles // must be last!
    };

    /// Display of sender prefix modes
#if QT_VERSION >= 0x050000
    enum class SenderPrefixMode {
#else
    enum SenderPrefixMode {
#endif
        NoModes = 0,      ///< Hide sender modes
        HighestMode = 1,  ///< Show the highest active sender mode
        AllModes = 2      ///< Show all active sender modes
    };
    // Do not change SenderPrefixMode numbering without also adjusting
    // ChatViewSettingsPage::initSenderPrefixComboBox() and chatviewsettingspage.ui "defaultValue"

    struct Format {
        FormatType type;
        QColor foreground;
        QColor background;
    };

    using FormatList = std::vector<std::pair<quint16, Format>>;

    struct StyledString {
        QString plainText;
        FormatList formatList; // starting pos, ftypes
    };

    class StyledMessage;

    /**
     * List of default sender colors
     *
     * In order from 1 - 16, matching the Sender## format in the settings file.
     * Don't change the length or values of the colors without updating the UI and color roles, too.
     *
     * @see ../qtui/settingspages/chatviewsettingspage.ui
     * @see UiStyle::ColorRole
     */
    const QList<QColor> defaultSenderColors = QList<QColor> {
        QColor(204,   0,   0),  ///< Sender00
        QColor(  0, 108, 173),  ///< Sender01
        QColor( 77, 153,   0),  ///< Sender02
        QColor(102,   0, 204),  ///< Sender03
        QColor(166, 125,   0),  ///< Sender04
        QColor(  0, 153,  39),  ///< Sender05
        QColor(  0,  48, 192),  ///< Sender06
        QColor(204,   0, 154),  ///< Sender07
        QColor(185,  70,   0),  ///< Sender08
        QColor(134, 153,   0),  ///< Sender09
        QColor( 20, 153,   0),  ///< Sender10
        QColor(  0, 153,  96),  ///< Sender11
        QColor(  0, 108, 173),  ///< Sender12
        QColor(  0, 153, 204),  ///< Sender13
        QColor(179,   0, 204),  ///< Sender14
        QColor(204,   0,  77),  ///< Sender15
    };
    // Explicitly declare QList<QColor> type for defaultSenderColors, otherwise error C2797
    // "list initialization inside member initializer list" will occur in Windows builds with Visual
    // Studio's compiler.
    //
    // See https://blogs.msdn.microsoft.com/vcblog/2014/08/19/the-future-of-non-static-data-member-initialization/
    // Note: Qt Creator flags this as invalid unless you set Clang in
    // Settings -> C++ -> Code Model -> Code Completion and Semantic Highlighting -> C
    //
    // See https://bugreports.qt.io/browse/QTCREATORBUG-1902

    /**
     * Default sender color for sent messages
     */
    const QColor defaultSenderColorSelf = QColor(0, 0, 0);

    static FormatType formatType(Message::Type msgType);
    static StyledString styleString(const QString &string, FormatType baseFormat = FormatType::Base);
    static QString mircToInternal(const QString &);

    /**
     * Gets if a custom timestamp format is used.
     *
     * @return True if custom timestamp format used, otherwise false
     */
    static inline bool useCustomTimestampFormat() { return _useCustomTimestampFormat; }

    /**
     * Gets the format string for chat log timestamps according to the system locale.
     *
     * This will return " hh:mm:ss" for system locales with 24-hour time or " h:mm:ss AP" for
     * systems with 12-hour time.
     *
     * @return String representing timestamp format according to system locale, e.g. " hh:mm:ss"
     */
    static QString systemTimestampFormatString();

    /**
     * Gets the format string for chat log timestamps, either system locale or custom.
     *
     * Depending on useCustomTimestampFormat(), this will return either the system locale based
     * time format, or the custom user-specified string.
     *
     * @return String representing timestamp format, e.g. "[hh:mm:ss]" or " hh:mm:ss"
     */
    static QString timestampFormatString();

    QTextCharFormat format(const Format &format, MessageLabel messageLabel) const;
    QFontMetricsF *fontMetrics(FormatType formatType, MessageLabel messageLabel) const;

    QList<QTextLayout::FormatRange> toTextLayoutList(const FormatList &, int textLength, MessageLabel messageLabel) const;

    inline const QBrush &brush(ColorRole role) const { return _uiStylePalette.at((int)role); }
    inline void setBrush(ColorRole role, const QBrush &brush) { _uiStylePalette[(int)role] = brush; }

    QVariant bufferViewItemData(const QModelIndex &networkModelIndex, int role) const;
    QVariant nickViewItemData(const QModelIndex &networkModelIndex, int role) const;

public slots:
    void reload();

signals:
    void changed();

protected:
    void loadStyleSheet();
    QString loadStyleSheet(const QString &name, bool shouldExist = false);

    QTextCharFormat parsedFormat(quint64 key) const;
    QTextCharFormat cachedFormat(const Format &format, MessageLabel messageLabel) const;
    void setCachedFormat(const QTextCharFormat &charFormat, const Format &format, MessageLabel messageLabel) const;
    void mergeFormat(QTextCharFormat &charFormat, const Format &format, MessageLabel messageLabel) const;
    void mergeSubElementFormat(QTextCharFormat &charFormat, FormatType formatType, MessageLabel messageLabel) const;
    void mergeColors(QTextCharFormat &charFormat, const Format &format, MessageLabel messageLabel) const;

    static FormatType formatType(const QString &code);
    static QString formatCode(FormatType);

    /**
     * Cache the system locale timestamp format string
     *
     * Based on whether or not AM/PM designators are used in the QLocale.timeFormat(), this extends
     * the application locale timestamp format string to include seconds.
     *
     * @see UiStyle::systemTimestampFormatString()
     */
    static void updateSystemTimestampFormat();

    /**
     * Updates the local setting cache of whether or not to use the custom timestamp format
     *
     * @param[in] enabled  If true, custom timestamp format used, otherwise false
     */
    static void setUseCustomTimestampFormat(bool enabled);

    /**
     * Updates the local setting cache of the timestamp format string
     *
     * @param[in] format   Timestamp format string
     */
    static void setTimestampFormatString(const QString &format);
    /**
     * Updates the local setting cache of how to display sender prefix modes
     *
     * @param[in] mode  Display format for sender prefix modes
     */
    static void setSenderPrefixDisplay(UiStyle::SenderPrefixMode mode);

    /**
     * Updates the local setting cache of whether or not to show sender brackets
     *
     * @param[in] enabled  If true, sender brackets are enabled, otherwise false.
     */
    static void enableSenderBrackets(bool enabled);

    QVariant itemData(int role, const QTextCharFormat &format) const;

private slots:
    void allowMircColorsChanged(const QVariant &);
    void showItemViewIconsChanged(const QVariant &);

private:
    QVector<QBrush> _uiStylePalette;
    QBrush _markerLineBrush;
    QHash<quint64, QTextCharFormat> _formats;
    mutable QHash<QString, QTextCharFormat> _formatCache;
    mutable QHash<quint64, QFontMetricsF *> _metricsCache;
    QHash<UiStyle::ItemFormatType, QTextCharFormat> _listItemFormats;
    static QHash<QString, FormatType> _formatCodes;
    static bool _useCustomTimestampFormat;        ///< If true, use the custom timestamp format
    static QString _systemTimestampFormatString;  ///< Cached copy of system locale timestamp format
    static QString _timestampFormatString;        ///< Timestamp format string
    static UiStyle::SenderPrefixMode _senderPrefixDisplay; ///< Prefix mode display before sender
    static bool _showSenderBrackets;              ///< If true, show brackets around sender names

    QIcon _channelJoinedIcon;
    QIcon _channelPartedIcon;
    QIcon _userOfflineIcon;
    QIcon _userOnlineIcon;
    QIcon _userAwayIcon;
    QIcon _categoryOpIcon;
    QIcon _categoryVoiceIcon;
    int _opIconLimit;
    int _voiceIconLimit;
    bool _showNickViewIcons;
    bool _showBufferViewIcons;
    bool _allowMircColors;
};


class UiStyle::StyledMessage : public Message
{
    Q_DECLARE_TR_FUNCTIONS(UiStyle::StyledMessage)

public:
    explicit StyledMessage(const Message &message);

    QString decoratedTimestamp() const;
    QString plainSender() const;           //!< Nickname (no decorations) for Plain and Notice, empty else
    QString decoratedSender() const;
    const QString &plainContents() const;

    const FormatList &contentsFormatList() const;

    quint8 senderHash() const;

protected:
    void style() const;

private:
    mutable StyledString _contents;
    mutable quint8 _senderHash;
};

#if QT_VERSION < 0x050000
uint qHash(UiStyle::ItemFormatType key);
#else
uint qHash(UiStyle::ItemFormatType key, uint seed);
#endif

// ---- Operators for dealing with enums ----------------------------------------------------------

UiStyle::FormatType operator|(UiStyle::FormatType lhs, UiStyle::FormatType rhs);
UiStyle::FormatType& operator|=(UiStyle::FormatType &lhs, UiStyle::FormatType rhs);
UiStyle::FormatType operator|(UiStyle::FormatType lhs, quint32 rhs);
UiStyle::FormatType& operator|=(UiStyle::FormatType &lhs, quint32 rhs);
UiStyle::FormatType operator&(UiStyle::FormatType lhs, UiStyle::FormatType rhs);
UiStyle::FormatType& operator&=(UiStyle::FormatType &lhs, UiStyle::FormatType rhs);
UiStyle::FormatType operator&(UiStyle::FormatType lhs, quint32 rhs);
UiStyle::FormatType& operator&=(UiStyle::FormatType &lhs, quint32 rhs);
UiStyle::FormatType& operator^=(UiStyle::FormatType &lhs, UiStyle::FormatType rhs);

UiStyle::MessageLabel operator|(UiStyle::MessageLabel lhs, UiStyle::MessageLabel rhs);
UiStyle::MessageLabel& operator|=(UiStyle::MessageLabel &lhs, UiStyle::MessageLabel rhs);
UiStyle::MessageLabel operator&(UiStyle::MessageLabel lhs, quint32 rhs);
UiStyle::MessageLabel& operator&=(UiStyle::MessageLabel &lhs, UiStyle::MessageLabel rhs);

// Shifts the label into the upper half of the return value
quint64 operator|(UiStyle::FormatType lhs, UiStyle::MessageLabel rhs);

UiStyle::ItemFormatType operator|(UiStyle::ItemFormatType lhs, UiStyle::ItemFormatType rhs);
UiStyle::ItemFormatType& operator|=(UiStyle::ItemFormatType &lhs, UiStyle::ItemFormatType rhs);

// ---- Allow for FormatList in QVariant ----------------------------------------------------------

QDataStream &operator<<(QDataStream &out, const UiStyle::FormatList &formatList);
QDataStream &operator>>(QDataStream &in, UiStyle::FormatList &formatList);

Q_DECLARE_METATYPE(UiStyle::FormatList)
Q_DECLARE_METATYPE(UiStyle::MessageLabel)
Q_DECLARE_METATYPE(UiStyle::SenderPrefixMode)
