#ifndef ORBITHUB_VNC_PIXEL_CODECS_H
#define ORBITHUB_VNC_PIXEL_CODECS_H

#include <QByteArray>
#include <QRect>
#include <QRgb>
#include <QVector>

// Pure, state-free decode helpers for VNC/RFB pixel encodings, kept out of
// VncSessionBackend so the wire-sequencing (when to read what off the
// socket) and wire-decoding (how to interpret already-buffered bytes) stay
// separate and the latter is unit-testable without a live connection.
namespace VncPixelCodecs {

// Converts one pixel's worth of raw bytes as sent under
// VncSessionBackend's negotiated SetPixelFormat (32bpp, little-endian,
// byte order B,G,R,pad) into a QRgb.
QRgb rgbFromPixelBytes(const uchar* bytes);

// A single filled rectangle, in tile-local coordinates (0,0 = the tile's
// own top-left corner, not the enclosing FramebufferUpdate rectangle's).
struct HextileSubrect {
    QRect rect;
    QRgb color = 0;
};

// RFC 6143 SS7.7.4 Hextile tile subencoding byte flags.
namespace HextileFlags {
constexpr quint8 kRaw = 0x01;
constexpr quint8 kBackgroundSpecified = 0x02;
constexpr quint8 kForegroundSpecified = 0x04;
constexpr quint8 kAnySubrects = 0x08;
constexpr quint8 kSubrectsColoured = 0x10;
}

// Byte length of a Hextile tile's "fixed" metadata -- the optional
// background/foreground color updates plus the optional subrect count --
// derivable from the subencoding byte alone, before any of those bytes are
// available. Only meaningful when HextileFlags::kRaw is *not* set (a Raw
// tile has no metadata at all, just tileWidth*tileHeight raw pixels).
int hextileFixedMetaByteCount(quint8 subencoding);

// Parses the `hextileFixedMetaByteCount(subencoding)` bytes described
// above. Updates *background/*foreground in place only when the
// corresponding flag is set in `subencoding` -- callers should persist
// their previous values across tiles in the same rectangle and pass them
// in here unchanged when a color isn't re-specified, since RFC 6143 has
// each tile inherit the last-specified colors. Returns the subrect count
// (0 if HextileFlags::kAnySubrects isn't set).
int decodeHextileFixedMeta(quint8 subencoding, const QByteArray& data, QRgb* background,
                           QRgb* foreground);

// Byte length of `subrectCount` subrects' worth of data, given whether
// they're individually colored (HextileFlags::kSubrectsColoured).
int hextileSubrectByteCount(bool coloured, int subrectCount);

// Parses `subrectCount` subrects (xy + wh bytes, plus a per-subrect color
// when `coloured`) out of `data`, substituting `foreground` in for any
// that aren't individually colored.
QVector<HextileSubrect> decodeHextileSubrects(bool coloured, int subrectCount,
                                              const QByteArray& data, QRgb foreground);

}

#endif