#include "app.h"

#include <unistd.h></unistd.h>

#include <x11 xutil.h=""></x11>

#include <x11 xkblib.h=""></x11>

#include <x11 extensions="" xtest.h=""></x11>

// prepare and shoose keys by algorithm from here:

//   https://www.x.org/releases/current/doc/libX11/libX11/libX11.html#Manipulating_the_Keyboard_Encoding

void inputPrepareKeysyms(unsigned int *ks0, unsigned int *ks1, int *isLetter, int *isKeypad) {

  if (!*ks0) *ks0 = *ks1;

  *isLetter = 0;

  if (*ks0) {

    KeySym kl = 0, ku = 0;

    XConvertCase(*ks0, &kl, &ku);

    if (*ks0 == kl && ku && kl != ku) {

      if (!*ks1) *ks1 = ku;

      *isLetter = 1;

    }

  }

  if (!*ks1) *ks1 = *ks0;

  *isKeypad = (0xFF80 <= *ks1 && *ks1 <= 0xFFBD) || (0x11000000 <= *ks1 && *ks1 <= 0x1100FFFF);

}

int inputChooseKeysym(unsigned int modifiers, unsigned int ks0, unsigned int ks1, int isLetter, int isKeypad) {

  if (!ks1) return 0;

  if (!ks0) return 1;

  // normalize bits to zero or one only

  isLetter = !!isLetter;

  isKeypad = !!isKeypad;

  int shift     = !!(modifiers & IM_SHIFT_BIT);

  int capsLock  = !!(modifiers & IM_CAPSLOCK_BIT);

  int shiftLock = !!(modifiers & IM_SHIFTLOCK_BIT);

  int numLock   = !!(modifiers & IM_NUMLOCK_BIT);

  if (capsLock) // capsLock priority

    shiftLock = 0;

  if (isKeypad)

    return numLock;

  if (!shift && !capsLock && !shiftLock)

    return 0;

  if (!shift && capsLock)

    return !!isLetter;

  if (shift && capsLock)

    return !isLetter;

  return shift || shiftLock;

}

int inputInit(Input *in, App *app) {

  LOGDBG("input: init");

  in->app = app;

  in->key0 = in->key1 = in->mapKey = 0;

  in->mapDown = 0;

  in->updated = 0;

  in->modifiers = 0;

  memset(in->keys, 0, sizeof(in->keys));

  memset(in->masks, 0, sizeof(in->masks));

  LOGDBG("input: init: connect to X11");

  in->dpy = XOpenDisplay(NULL);

  if (!in->dpy)

    return LOGERR("input: init: cannot connect to X11");

  LOGDBG("input: init: query keycode range");

  XDisplayKeycodes(in->dpy, &in->key0, &in->key1);

  ++in->key1;

  if (in->key0 < 0) in->key0 = 0;

  if (in->key1 > IN_MAXKEYS) in->key1 = IN_MAXKEYS;

  LOGDBG("input: init: keycode range [%d, %d)", in->key0, in->key1);

  inputUpdateLayout(in);

  inputUpdateModifiers(in);

  return 1;

}

void inputDeinit(Input *in) {

  LOGDBG("input: deinit");

  if (in->mapKey) {

    LOGDBG("input: deinit: unmap temporary key %d", in->mapKey);

    if (in->mapDown)

      inputEvent(in, in->mapKey, 0);

    KeySym ks[4] = {};

    XChangeKeyboardMapping(in->dpy, in->mapKey, 4, ks, 1);

  }

  XCloseDisplay(in->dpy);

}

void inputUpdateLayout(Input *in) {

  LOGDBG("input: update layout");

  static const KeySym imKeys[IM_COUNT] = {

    XK_Shift_L,

    XK_Caps_Lock,

    XK_Shift_Lock,

    XK_Num_Lock,

    XK_Mode_switch,

    XK_Scroll_Lock };

  in->updated = 0;

  memset(in->masks, 0, sizeof(in->masks));

  LOGDBG("input: update layout: read modifiers");

  XModifierKeymap *mods = XGetModifierMapping(in->dpy);

  LOGDBG("input: update layout: read keyboard mapping");

  int mcnt = 0;

  KeySym *ks = XGetKeyboardMapping(in->dpy, in->key0, in->key1 - in->key0, &mcnt);

  for(int i = in->key0; i < in->key1; ++i, ks += mcnt) {

    // search key for temporary maps

    if (!in->mapKey) {

      int found = 1;

      for(int i = 0; i < mcnt; ++i)

        if (ks[i]) { found = 0; break; }

      if (found) {

        in->mapKey = i;

        LOGDBG("input: update layout: choose keycode for temporary map: %d", in->mapKey);

      }

    }

    //if (i == 50 || i == 62 || i == 66) {

    //  printf("keysyms for key #%d (%d):\n", i, mcnt);

    //  for(int i = 0; i < mcnt; ++i) {

    //    printf("  %lu\n", ks[i]);

    //  }

    //  printf("\n");

    //}

    // update state masks

    for(int imask = 0; imask < IM_COUNT; ++imask)

      for(int iks = 0; iks < mcnt; ++iks)

        if (ks[iks] == imKeys[imask]) {

          LOGDBG("input: update layout: keycode for mask %d is %d", imask, i);

          for(int imod = 0; imod < XkbNumModifiers; ++imod)

            for(int ik = 0; ik < mods->max_keypermod; ++ik)

              if (mods->modifiermap[imod*mods->max_keypermod + ik] == i)

                in->masks[imask] |= 1 << imod;

        }

    // get base keys

    unsigned int k[] = {

      mcnt > 0 ? ks[0] : 0,

      mcnt > 1 ? ks[1] : 0,

      mcnt > 2 ? ks[2] : 0,

      mcnt > 3 ? ks[3] : 0 };

    if (!k[2] && !k[3])

      k[2] = k[0], k[3] = k[1];

    int isLetter[2] = {};

    int isKeypad[2] = {};

    inputPrepareKeysyms(&k[0], &k[1], &isLetter[0], &isKeypad[0]);

    // fill key modes

    for(unsigned int modifiers = 0; modifiers < (1 << IM_COUNT); ++modifiers) {

      int g = !!(modifiers & IM_GROUP_BIT);

      int ki = inputChooseKeysym(modifiers, k[g*2], k[g*2 + 1], isLetter[g], isKeypad[g]);

      in->keys[i][modifiers] = k[g*2 + ki];

    }

  }

  // Shift modifier index must be 0

  in->masks[IM_SHIFT] = 1 << 0;

  // when caps and shift locks in the same modifier - this modifier is CapsLock

  in->masks[IM_SHIFTLOCK] &= ~in->masks[IM_CAPSLOCK];

  // Lock modifier index must be 1

  in->masks[IM_CAPSLOCK] &= 1 << 1;

  in->masks[IM_SHIFTLOCK] &= 1 << 1;

  XFreeModifiermap(mods);

  for(int i = 0; i < IM_COUNT; ++i)

    LOGDBG("input: update layout: masks[%d] = %08u", i, in->masks[i]);

}

void inputUpdateModifiers(Input *in) {

  LOGDBG("input: update modifiers");

  XkbStateRec state = {};

  XkbGetState(in->dpy, XkbUseCoreKbd, &state);

  in->modifiers = 0;

  for(int i = 0; i < IM_COUNT; ++i)

    if (in->masks[i] & state.mods)

      in->modifiers |= (1 << i);

  LOGDBG("input: update modifiers: current state %08x, chosen mod %02x", state.mods, in->modifiers);

}

int inputKeycode(Input *in, unsigned int keySym) {

  LOGDBG("input: keycode: keySym=%u", keySym);

  if (!keySym)

    return 0;

  for(int i = in->key0; i < in->key1; ++i) {

    if (in->keys[i][in->modifiers] == keySym) {

      LOGDBG("input: keycode: found keycode %d", i);

      return i;

    }

  }

  if (!in->mapKey) {

    LOGWRN("input: keycode: no keycode mapped to keySym[%u], and no free keycodes for temporary mapping", keySym);

    return 0;

  }

  LOGDBG("input: keycode: temporary remap keySym[%u] to %d", keySym, in->mapKey);

  if (in->mapDown) {

    LOGWRN("input: event: temporary remap: mapped keys collision, release previously mapped key");

    inputEvent(in, in->mapKey, 0);

  }

  for(int i = 0; i < IM_COUNT; ++i)

    in->keys[in->mapKey][i] = keySym;

  KeySym ks[4] = { keySym, keySym, keySym, keySym };

  XChangeKeyboardMapping(in->dpy, in->mapKey, 4, ks, 1);

  XSync(in->dpy, False);

  in->updated = 1;

  return in->mapKey;

}

void inputEvent(Input *in, int keycode, int press) {

  LOGDBG("input: event: keycode=%d press=%d", keycode, press);

  press = !!press;

  if (keycode < in->key0 || keycode >= in->key1) {

    LOGERR("input: event: bad keycode=%d", keycode);

    return;

  }

  XTestFakeKeyEvent(in->dpy, keycode, press, CurrentTime);

  XSync(in->dpy, False);

  inputUpdateModifiers(in);

}