/*
 * InputLeap -- mouse and keyboard sharing utility
 * Copyright (C) 2012-2016 Symless Ltd.
 * Copyright (C) 2002 Chris Schoeneman
 *
 * This package is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * found in the file LICENSE that should have accompanied this file.
 *
 * This package 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, see <http://www.gnu.org/licenses/>.
 */

#pragma once

#include "inputleap/clipboard_types.h"
#include "inputleap/IClipboard.h"
#include "XWindowsImpl.h"

#include <X11/Xlib.h>

#include <map>
#include <list>
#include <vector>

namespace inputleap {

class IXWindowsClipboardConverter;

//! X11 clipboard implementation
class XWindowsClipboard : public IClipboard {
public:
    /*!
    Use \c window as the window that owns or interacts with the
    clipboard identified by \c id.
    */
    XWindowsClipboard(IXWindowsImpl* impl, Display*, Window window,
                      ClipboardID id);
    virtual ~XWindowsClipboard();

    //! Notify clipboard was lost
    /*!
    Tells clipboard it lost ownership at the given time.
    */
    void lost(Time);

    //! Add clipboard request
    /*!
    Adds a selection request to the request list.  If the given
    owner window isn't this clipboard's window then this simply
    sends a failure event to the requestor.
    */
    void addRequest(Window owner,
                            Window requestor, Atom target,
                            ::Time time, Atom property);

    //! Process clipboard request
    /*!
    Continues processing a selection request.  Returns true if the
    request was handled, false if the request was unknown.
    */
    bool processRequest(Window requestor,
                            ::Time time, Atom property);

    //! Cancel clipboard request
    /*!
    Terminate a selection request.  Returns true iff the request
    was known and handled.
    */
    bool destroyRequest(Window requestor);

    //! Get window
    /*!
    Returns the clipboard's window (passed the c'tor).
    */
    Window getWindow() const;

    //! Get selection atom
    /*!
    Returns the selection atom that identifies the clipboard to X11
    (e.g. XA_PRIMARY).
    */
    Atom getSelection() const;

    // IClipboard overrides
    bool clear() override;
    void add(EFormat, const std::string& data) override;
    bool open(Time) const override;
    void close() const override;
    Time getTime() const override;
    bool has(EFormat) const override;
    std::string get(EFormat) const override;

private:
    // remove all converters from our list
    void clearConverters();

    // get the converter for a clipboard format.  returns nullptr if no
    // suitable converter.  iff onlyIfNotAdded is true then also
    // return nullptr if a suitable converter was found but we already
    // have data of the converter's clipboard format.
    IXWindowsClipboardConverter*
                        getConverter(Atom target,
                            bool onlyIfNotAdded = false) const;

    // convert target atom to clipboard format
    EFormat getFormat(Atom target) const;

    // add a non-MULTIPLE request.  does not verify that the selection
    // was owned at the given time.  returns true if the conversion
    // could be performed, false otherwise.  in either case, the
    // reply is inserted.
    bool addSimpleRequest(
                            Window requestor, Atom target,
                            ::Time time, Atom property);

    // if not already checked then see if the cache is stale and, if so,
    // clear it.  this has the side effect of updating m_timeOwned.
    void checkCache() const;

    // clear the cache, resetting the cached flag and the added flag for
    // each format.
    void clearCache() const;
    void doClearCache();

    // cache all formats of the selection
    void fillCache() const;
    void doFillCache();

    //
    // helper classes
    //

    // read an ICCCM conforming selection
    class CICCCMGetClipboard {
    public:
        CICCCMGetClipboard(Window requestor, Time time, Atom property);
        ~CICCCMGetClipboard();

        // convert the given selection to the given type.  returns
        // true iff the conversion was successful or the conversion
        // cannot be performed (in which case *actualTarget == None).
        bool readClipboard(Display* display,
                            Atom selection, Atom target,
                            Atom* actualTarget, std::string* data);

    private:
        bool processEvent(Display* display, XEvent* event);

    private:
        Window m_requestor;
        Time m_time;
        Atom m_property;
        bool m_incr;
        bool m_failed;
        bool m_done;

        // atoms needed for the protocol
        Atom m_atomNone;        // NONE, not None
        Atom m_atomIncr;

        // true iff we've received the selection notify
        bool m_reading;

        // the converted selection data
        std::string* m_data;

        // the actual type of the data.  if this is None then the
        // selection owner cannot convert to the requested type.
        Atom* m_actualTarget;

    public:
        // true iff the selection owner didn't follow ICCCM conventions
        bool m_error;
    };

    // Motif structure IDs
    enum { kMotifClipFormat = 1, kMotifClipItem, kMotifClipHeader };

    // _MOTIF_CLIP_HEADER structure
    class MotifClipHeader {
    public:
        std::int32_t m_id;            // kMotifClipHeader
        std::int32_t m_pad1[3];
        std::int32_t m_item;
        std::int32_t m_pad2[4];
        std::int32_t m_numItems;
        std::int32_t m_pad3[3];
        std::int32_t m_selectionOwner;    // a Window
        std::int32_t m_pad4[2];
    };

    // Motif clip item structure
    class MotifClipItem {
    public:
        std::int32_t m_id;            // kMotifClipItem
        std::int32_t m_pad1[5];
        std::int32_t m_size;
        std::int32_t m_numFormats;
        std::int32_t m_numDeletedFormats;
        std::int32_t m_pad2[6];
    };

    // Motif clip format structure
    class MotifClipFormat {
    public:
        std::int32_t m_id;            // kMotifClipFormat
        std::int32_t m_pad1[6];
        std::int32_t m_length;
        std::int32_t m_data;
        std::int32_t m_type;            // an Atom
        std::int32_t m_pad2[1];
        std::int32_t m_deleted;
        std::int32_t m_pad3[4];
    };

    // stores data needed to respond to a selection request
    class Reply {
    public:
        Reply(Window, Atom target, ::Time);
        Reply(Window, Atom target, ::Time, Atom property, const std::string& data,
              Atom type, int format);

    public:
        // information about the request
        Window m_requestor;
        Atom m_target;
        ::Time m_time;
        Atom m_property;

        // true iff we've sent the notification for this reply
        bool m_replied;

        // true iff the reply has sent its last message
        bool m_done;

        // the data to send and its type and format
        std::string m_data;
        Atom m_type;
        int m_format;

        // index of next byte in m_data to send
        std::uint32_t m_ptr;
    };
    typedef std::list<Reply*> ReplyList;
    typedef std::map<Window, ReplyList> ReplyMap;
    typedef std::map<Window, long> ReplyEventMask;

    // ICCCM interoperability methods
    void icccmFillCache();
    bool icccmGetSelection(Atom target, Atom* actualTarget, std::string* data) const;
    Time icccmGetTime() const;

    // motif interoperability methods
    bool motifLockClipboard() const;
    void motifUnlockClipboard() const;
    bool motifOwnsClipboard() const;
    void motifFillCache();
    bool motifGetSelection(const MotifClipFormat*, Atom* actualTarget, std::string* data) const;
    Time motifGetTime() const;

    // reply methods
    bool insertMultipleReply(Window, ::Time, Atom);
    void insertReply(Reply*);
    void pushReplies();
    void pushReplies(ReplyMap::iterator&,
                            ReplyList&, ReplyList::iterator);
    bool sendReply(Reply*);
    void clearReplies();
    void clearReplies(ReplyList&);
    void sendNotify(Window requestor, Atom selection,
                            Atom target, Atom property, Time time);
    bool wasOwnedAtTime(::Time) const;

    // data conversion methods
    Atom getTargetsData(std::string&, int* format) const;
    Atom getTimestampData(std::string&, int* format) const;

private:
    typedef std::vector<IXWindowsClipboardConverter*> ConverterList;
    IXWindowsImpl* m_impl;

    Display* m_display;
    Window m_window;
    ClipboardID m_id;
    Atom m_selection;
    mutable bool m_open;
    mutable Time m_time;
    bool m_owner;
    mutable Time m_timeOwned;
    Time m_timeLost;

    // true iff open and clipboard owned by a motif app
    mutable bool m_motif;

    // the added/cached clipboard data
    mutable bool m_checkCache;
    bool m_cached;
    Time m_cacheTime;
    bool m_added[kNumFormats];
    std::string m_data[kNumFormats];

    // conversion request replies
    ReplyMap m_replies;
    ReplyEventMask m_eventMasks;

    // clipboard format converters
    ConverterList m_converters;

    // atoms we'll need
    Atom m_atomTargets;
    Atom m_atomMultiple;
    Atom m_atomTimestamp;
    Atom m_atomInteger;
    Atom m_atomAtom;
    Atom m_atomAtomPair;
    Atom m_atomData;
    Atom m_atomINCR;
    Atom m_atomMotifClipLock;
    Atom m_atomMotifClipHeader;
    Atom m_atomMotifClipAccess;
    Atom m_atomGDKSelection;
};

//! Clipboard format converter interface
/*!
This interface defines the methods common to all X11 clipboard format
converters.
*/
class IXWindowsClipboardConverter {
public:
    virtual ~IXWindowsClipboardConverter() { }

    //! @name accessors
    //@{

    //! Get clipboard format
    /*!
    Return the clipboard format this object converts from/to.
    */
    virtual IClipboard::EFormat
                        getFormat() const = 0;

    //! Get X11 format atom
    /*!
    Return the atom representing the X selection format that
    this object converts from/to.
    */
    virtual Atom getAtom() const = 0;

    //! Get X11 property datum size
    /*!
    Return the size (in bits) of data elements returned by
    toIClipboard().
    */
    virtual int getDataSize() const = 0;

    //! Convert from IClipboard format
    /*!
    Convert from the IClipboard format to the X selection format.
    The input data must be in the IClipboard format returned by
    getFormat().  The return data will be in the X selection
    format returned by getAtom().
    */
    virtual std::string fromIClipboard(const std::string&) const = 0;

    //! Convert to IClipboard format
    /*!
    Convert from the X selection format to the IClipboard format
    (i.e., the reverse of fromIClipboard()).
    */
    virtual std::string toIClipboard(const std::string&) const = 0;

    //@}
};

} // namespace inputleap
