/*
Looking Glass - KVM FrameRelay (KVMFR) Client
Copyright (C) 2017-2019 Geoffrey McRae <geoff@hostfission.com>
https://looking-glass.hostfission.com

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) 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 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., 59 Temple
Place, Suite 330, Boston, MA 02111-1307 USA
*/

#include "interface/clipboard.h"
#include "common/debug.h"

#include <X11/extensions/Xfixes.h>

struct state
{
  Display             * display;
  Window                window;
  Atom                  aSelection;
  Atom                  aCurSelection;
  Atom                  aTargets;
  Atom                  aSelData;
  Atom                  aIncr;
  Atom                  aTypes[LG_CLIPBOARD_DATA_NONE];
  LG_ClipboardReleaseFn releaseFn;
  LG_ClipboardRequestFn requestFn;
  LG_ClipboardNotifyFn  notifyFn;
  LG_ClipboardDataFn    dataFn;
  LG_ClipboardData      type;

  bool         incrStart;
  unsigned int lowerBound;

  // XFixes vars
  int eventBase;
  int errorBase;
};

static struct state * this = NULL;

static const char * atomTypes[] =
{
  "UTF8_STRING",
  "image/png",
  "image/bmp",
  "image/tiff",
  "image/jpeg"
};

static const char * x11_cb_getName()
{
  return "X11";
}

static bool x11_cb_init(
    SDL_SysWMinfo         * wminfo,
    LG_ClipboardReleaseFn   releaseFn,
    LG_ClipboardNotifyFn    notifyFn,
    LG_ClipboardDataFn      dataFn)
{
  // final sanity check
  if (wminfo->subsystem != SDL_SYSWM_X11)
  {
    DEBUG_ERROR("wrong subsystem");
    return false;
  }

  this = (struct state *)malloc(sizeof(struct state));
  memset(this, 0, sizeof(struct state));

  this->display       = wminfo->info.x11.display;
  this->window        = wminfo->info.x11.window;
  this->aSelection    = XInternAtom(this->display, "CLIPBOARD"  , False);
  this->aTargets      = XInternAtom(this->display, "TARGETS"    , False);
  this->aSelData      = XInternAtom(this->display, "SEL_DATA"   , False);
  this->aIncr         = XInternAtom(this->display, "INCR"       , False);
  this->aCurSelection = BadValue;
  this->releaseFn     = releaseFn;
  this->notifyFn      = notifyFn;
  this->dataFn        = dataFn;

  for(int i = 0; i < LG_CLIPBOARD_DATA_NONE; ++i)
  {
    this->aTypes[i] = XInternAtom(this->display, atomTypes[i], False);
    if (this->aTypes[i] == BadAlloc || this->aTypes[i] == BadValue)
    {
      DEBUG_ERROR("failed to get atom for type: %s", atomTypes[i]);
      free(this);
      this = NULL;
      return false;
    }
  }

  // we need the raw X events
  SDL_EventState(SDL_SYSWMEVENT, SDL_ENABLE);

  // use xfixes to get clipboard change notifications
  if (!XFixesQueryExtension(this->display, &this->eventBase, &this->errorBase))
  {
    DEBUG_ERROR("failed to initialize xfixes");
    free(this);
    this = NULL;
    return false;
  }

  XFixesSelectSelectionInput(this->display, this->window, XA_PRIMARY      , XFixesSetSelectionOwnerNotifyMask);
  XFixesSelectSelectionInput(this->display, this->window, this->aSelection, XFixesSetSelectionOwnerNotifyMask);

  return true;
}

static void x11_cb_free()
{
  free(this);
  this = NULL;
}

static void x11_cb_reply_fn(void * opaque, LG_ClipboardData type, uint8_t * data, uint32_t size)
{
  XEvent *s = (XEvent *)opaque;

  XChangeProperty(
      this->display          ,
      s->xselection.requestor,
      s->xselection.property ,
      s->xselection.target   ,
      8,
      PropModeReplace,
      data,
      size);

  XSendEvent(this->display, s->xselection.requestor, 0, 0, s);
  XFlush(this->display);
  free(s);
}

static void x11_cb_selection_request(const XSelectionRequestEvent e)
{
  XEvent * s = (XEvent *)malloc(sizeof(XEvent));
  s->xselection.type      = SelectionNotify;
  s->xselection.requestor = e.requestor;
  s->xselection.selection = e.selection;
  s->xselection.target    = e.target;
  s->xselection.property  = e.property;
  s->xselection.time      = e.time;

  if (!this->requestFn)
    goto nodata;

  // target list requested
  if (e.target == this->aTargets)
  {
    Atom targets[2];
    targets[0] = this->aTargets;
    targets[1] = this->aTypes[this->type];

    XChangeProperty(
        e.display,
        e.requestor,
        e.property,
        XA_ATOM,
        32,
        PropModeReplace,
        (unsigned char*)targets,
        sizeof(targets) / sizeof(Atom));

    goto send;
  }

  // look to see if we can satisfy the data type
  for(int i = 0; i < LG_CLIPBOARD_DATA_NONE; ++i)
    if (this->aTypes[i] == e.target && this->type == i)
    {
      // request the data
      this->requestFn(x11_cb_reply_fn, s);
      return;
    }

nodata:
  // report no data
  s->xselection.property = None;

send:
  XSendEvent(this->display, e.requestor, 0, 0, s);
  XFlush(this->display);
  free(s);
}

static void x11_cb_selection_clear(const XSelectionClearEvent e)
{
  if (e.selection != XA_PRIMARY && e.selection != this->aSelection)
    return;

  this->aCurSelection = BadValue;
  this->releaseFn();
  return;
}

static void x11_cb_xfixes_selection_notify(const XFixesSelectionNotifyEvent e)
{
  // check if the selection is valid and it isn't ourself
  if ((e.selection != XA_PRIMARY && e.selection != this->aSelection) ||
      e.owner == this->window || e.owner == 0)
  {
    return;
  }

  // remember which selection we are working with
  this->aCurSelection = e.selection;
  XConvertSelection(
      this->display,
      e.selection,
      this->aTargets,
      this->aTargets,
      this->window,
      CurrentTime);

  return;
}

static void x11_cb_selection_incr(const XPropertyEvent e)
{
  Atom type;
  int format;
  unsigned long itemCount, after;
  unsigned char *data;

  if (XGetWindowProperty(
      e.display,
      e.window,
      e.atom,
      0, ~0L, // start and length
      True,   // delete the property
      this->aIncr,
      &type,
      &format,
      &itemCount,
      &after,
      &data) != Success)
  {
    DEBUG_INFO("GetProp Failed");
    this->notifyFn(LG_CLIPBOARD_DATA_NONE, 0);
    goto out;
  }

  LG_ClipboardData dataType;
  for(dataType = 0; dataType < LG_CLIPBOARD_DATA_NONE; ++dataType)
    if (this->aTypes[dataType] == type)
      break;

  if (dataType == LG_CLIPBOARD_DATA_NONE)
  {
    DEBUG_WARN("clipboard data (%s) not in a supported format",
        XGetAtomName(this->display, type));

    this->lowerBound = 0;
    this->notifyFn(LG_CLIPBOARD_DATA_NONE, 0);
    goto out;
  }

  if (this->incrStart)
  {
    this->notifyFn(dataType, this->lowerBound);
    this->incrStart = false;
  }

  XFree(data);
  data = NULL;

  if (XGetWindowProperty(
      e.display,
      e.window,
      e.atom,
      0, ~0L, // start and length
      True,   // delete the property
      type,
      &type,
      &format,
      &itemCount,
      &after,
      &data) != Success)
  {
    DEBUG_ERROR("XGetWindowProperty Failed");
    this->notifyFn(LG_CLIPBOARD_DATA_NONE, 0);
    goto out;
  }

  this->dataFn(dataType, data, itemCount);
  this->lowerBound -= itemCount;

out:
  if (data)
    XFree(data);
}

static void x11_cb_selection_notify(const XSelectionEvent e)
{
  if (e.property == None)
    return;

  Atom type;
  int format;
  unsigned long itemCount, after;
  unsigned char *data;

  if (XGetWindowProperty(
      e.display,
      e.requestor,
      e.property,
      0, ~0L, // start and length
      True  , // delete the property
      AnyPropertyType,
      &type,
      &format,
      &itemCount,
      &after,
      &data) != Success)
  {
    this->notifyFn(LG_CLIPBOARD_DATA_NONE, 0);
    goto out;
  }

  if (type == this->aIncr)
  {
    this->incrStart  = true;
    this->lowerBound = *(unsigned int *)data;
    goto out;
  }

  // the target list
  if (e.property == this->aTargets)
  {
    // the format is 32-bit and we must have data
    // this is technically incorrect however as it's
    // an array of padded 64-bit values
    if (!data || format != 32)
      goto out;

    // see if we support any of the targets listed
    const uint64_t * targets = (const uint64_t *)data;
    for(unsigned long i = 0; i < itemCount; ++i)
    {
      for(int n = 0; n < LG_CLIPBOARD_DATA_NONE; ++n)
        if (this->aTypes[n] == targets[i])
        {
          // we have a match, so send the notification
          this->notifyFn(n, 0);
          goto out;
        }
    }

    // no matches
    this->notifyFn(LG_CLIPBOARD_DATA_NONE, 0);
    goto out;
  }

  if (e.property == this->aSelData)
  {
    LG_ClipboardData dataType;
    for(dataType = 0; dataType < LG_CLIPBOARD_DATA_NONE; ++dataType)
      if (this->aTypes[dataType] == type)
        break;

    if (dataType == LG_CLIPBOARD_DATA_NONE)
    {
      DEBUG_WARN("clipboard data (%s) not in a supported format",
          XGetAtomName(this->display, type));
      goto out;
    }

    this->dataFn(dataType, data, itemCount);
    goto out;
  }

out:
  if (data)
    XFree(data);
}

static void x11_cb_wmevent(SDL_SysWMmsg * msg)
{
  XEvent e = msg->msg.x11.event;

  switch(e.type)
  {
    case SelectionRequest:
      x11_cb_selection_request(e.xselectionrequest);
      break;

    case SelectionClear:
      x11_cb_selection_clear(e.xselectionclear);
      break;

    case SelectionNotify:
      x11_cb_selection_notify(e.xselection);
      break;

    case PropertyNotify:
      if (e.xproperty.display != this->display    ||
          e.xproperty.window  != this->window     ||
          e.xproperty.atom    != this->aSelData   ||
          e.xproperty.state   != PropertyNewValue ||
          this->lowerBound    == 0)
        break;

      x11_cb_selection_incr(e.xproperty);
      break;

    default:
      if (e.type == this->eventBase + XFixesSelectionNotify)
      {
        XFixesSelectionNotifyEvent * sne = (XFixesSelectionNotifyEvent *)&e;
        x11_cb_xfixes_selection_notify(*sne);
      }
      break;
  }
}

static void x11_cb_notice(LG_ClipboardRequestFn requestFn, LG_ClipboardData type)
{
  this->requestFn = requestFn;
  this->type      = type;
  XSetSelectionOwner(this->display, XA_PRIMARY      , this->window, CurrentTime);
  XSetSelectionOwner(this->display, this->aSelection, this->window, CurrentTime);
  XFlush(this->display);
}

static void x11_cb_release()
{
  this->requestFn = NULL;
  XSetSelectionOwner(this->display, XA_PRIMARY      , None, CurrentTime);
  XSetSelectionOwner(this->display, this->aSelection, None, CurrentTime);
  XFlush(this->display);
}

static void x11_cb_request(LG_ClipboardData type)
{
  if (this->aCurSelection == BadValue)
    return;

  XConvertSelection(
      this->display,
      this->aCurSelection,
      this->aTypes[type],
      this->aSelData,
      this->window,
      CurrentTime);
}

const LG_Clipboard LGC_X11 =
{
  .getName = x11_cb_getName,
  .init    = x11_cb_init,
  .free    = x11_cb_free,
  .wmevent = x11_cb_wmevent,
  .notice  = x11_cb_notice,
  .release = x11_cb_release,
  .request = x11_cb_request
};