/*
 *   Rosimildo da Silva:  rdasilva@connecttel.com
 */

#include <limits.h>
#include <sys/types.h>
#include <rtems/keyboard.h>
#include "i386kbd.h"
#include <rtems/kd.h>
#include <bsp.h>
#include <bsp/bootcard.h>
#include <stdatomic.h>

#define SIZE(x) (sizeof(x)/sizeof((x)[0]))

#ifndef KBD_DEFMODE
#define KBD_DEFMODE ((1 << VC_REPEAT) | (1 << VC_META))
#endif

#ifndef KBD_DEFLEDS
/*
 * Some laptops take the 789uiojklm,. keys as number pad when NumLock
 * is on. This seems a good reason to start with NumLock off.
 */
#define KBD_DEFLEDS 0
#endif

#ifndef KBD_DEFLOCK
#define KBD_DEFLOCK 0
#endif

static int kbd_test_and_set_bit(int nr, atomic_uint_least32_t * addr)
{
  uint_least32_t        mask;
  int                   retval;

  addr += nr >> 5;
  mask = 1UL << (nr & 0x1f);

  retval = (atomic_fetch_or(addr, mask) & mask) != 0;

  return retval;
}

static int kbd_test_and_clear_bit(int nr, atomic_uint_least32_t * addr)
{
  uint_least32_t        mask;
  int                   retval;

  addr += nr >> 5;
  mask = 1UL << (nr & 0x1f);

  retval = (atomic_fetch_and(addr, ~mask) & mask) != 0;

  return retval;
}

static int kbd_test_bit(int nr, atomic_uint_least32_t * addr)
{
  unsigned long  mask;

  addr += nr >> 5;
  mask = 1 << (nr & 0x1f);
  return ((mask & atomic_load(addr)) != 0);
}

/*
 * global state includes the following, and various static variables
 * in this module: prev_scancode, shift_state, diacr, npadch, dead_key_next.
 * (last_console is now a global variable)
 */
#define  KBD_BITS_PER_ELEMENT (sizeof(atomic_uint_least32_t)*CHAR_BIT)

/* shift state counters.. */
static unsigned char k_down[NR_SHIFT] = {0, };
/* keyboard key bitmap */
static atomic_uint_least32_t
  key_down[(256 + KBD_BITS_PER_ELEMENT - 1) / KBD_BITS_PER_ELEMENT] = { 0, };

static int dead_key_next = 0;
/*
 * In order to retrieve the shift_state (for the mouse server), either
 * the variable must be global, or a new procedure must be created to
 * return the value. I chose the former way.
 */
int shift_state = 0;
static int npadch = -1;      /* -1 or number assembled on pad */
static unsigned char diacr = 0;
static char rep = 0;      /* flag telling character repeat */

/* default console for RTEMS */
static int  fg_console = 0;

struct kbd_struct kbd_table[MAX_NR_CONSOLES];
static struct kbd_struct * kbd = kbd_table;

void compute_shiftstate(void);

typedef void (*k_hand)(unsigned char value, char up_flag);
typedef void (k_handfn)(unsigned char value, char up_flag);

static k_handfn
  do_self, do_fn, do_spec, do_pad, do_dead, do_cons, do_cur, do_shift,
  do_meta, do_ascii, do_lock, do_lowercase, do_slock, do_dead2,
  do_ignore;

static k_hand key_handler[16] = {
  do_self, do_fn, do_spec, do_pad, do_dead, do_cons, do_cur, do_shift,
  do_meta, do_ascii, do_lock, do_lowercase, do_slock, do_dead2,
  do_ignore, do_ignore
};

/* Key types processed even in raw modes */

#define TYPES_ALLOWED_IN_RAW_MODE ((1 << KT_SPEC) | (1 << KT_SHIFT))

typedef void (*void_fnp)(void);
typedef void (void_fn)(void);

static void show_mem(void)
{
}
static void show_state(void)
{
}

static void_fn do_null, enter, show_ptregs, send_intr, lastcons, caps_toggle,
  num, hold, scroll_forw, scroll_back, caps_on, compose,
  SAK, decr_console, incr_console, spawn_console, bare_num;

static void_fnp spec_fn_table[] = {
  do_null,  enter,    show_ptregs,  show_mem,
  show_state,  send_intr,  lastcons,  caps_toggle,
  num,    hold,    scroll_forw,  scroll_back,
  bsp_reset,  caps_on,  compose,  SAK,
  decr_console,  incr_console,  spawn_console,  bare_num
};

#define SPECIALS_ALLOWED_IN_RAW_MODE (1 << KVAL(K_SAK))

/* maximum values each key_handler can handle */
const int max_vals[] = {
  255, SIZE(func_table) - 1, SIZE(spec_fn_table) - 1, NR_PAD - 1,
  NR_DEAD - 1, 255, 3, NR_SHIFT - 1,
  255, NR_ASCII - 1, NR_LOCK - 1, 255,
  NR_LOCK - 1, 255
};

const int NR_TYPES = SIZE(max_vals);

/* N.B. drivers/macintosh/mac_keyb.c needs to call put_queue */
static void put_queue(int);
static unsigned char handle_diacr(unsigned char);

#ifdef CONFIG_MAGIC_SYSRQ
static int sysrq_pressed;
#endif

/*
 * Many other routines do put_queue, but I think either
 * they produce ASCII, or they produce some user-assigned
 * string, and in both cases we might assume that it is
 * in utf-8 already.
 */
static void to_utf8(ushort c)
{
  if (c < 0x80)
    put_queue(c);                  /*  0*******  */
  else if (c < 0x800) {
    put_queue(0xc0 | (c >> 6));    /*  110***** 10******  */
    put_queue(0x80 | (c & 0x3f));
  } else {
    put_queue(0xe0 | (c >> 12));   /*  1110**** 10****** 10******  */
    put_queue(0x80 | ((c >> 6) & 0x3f));
    put_queue(0x80 | (c & 0x3f));
  }
  /* UTF-8 is defined for words of up to 31 bits,
     but we need only 16 bits here */
}

/*
 * Translation of escaped scancodes to keycodes.
 * This is now user-settable (for machines were it makes sense).
 */

int setkeycode(unsigned int scancode, unsigned int keycode)
{
    return kbd_setkeycode(scancode, keycode);
}

int getkeycode(unsigned int scancode)
{
    return kbd_getkeycode(scancode);
}

void handle_scancode(unsigned char scancode, int down)
{
  unsigned char keycode;
  char up_flag = down ? 0 : 0200;
  char raw_mode;

  mark_bh(CONSOLE_BH);

#if 0
  tty = ttytab? ttytab[fg_console]: NULL;
  if (tty && (!tty->driver_data)) {
    /*
     * We touch the tty structure via the the ttytab array
     * without knowing whether or not tty is open, which
     * is inherently dangerous.  We currently rely on that
     * fact that console_open sets tty->driver_data when
     * it opens it, and clears it when it closes it.
     */
    tty = NULL;
  }
#endif

  kbd = kbd_table + fg_console;
  if ((raw_mode = (kbd->kbdmode == VC_RAW))) {
    put_queue(scancode | up_flag);
    /* we do not return yet, because we want to maintain
       the key_down array, so that we have the correct
       values when finishing RAW mode or when changing VT's */
  }

  /*
   *  Convert scancode to keycode
   */
  if (!kbd_translate(scancode, &keycode, raw_mode))
      return;

  /*
   * At this point the variable `keycode' contains the keycode.
   * Note: the keycode must not be 0 (++Geert: on m68k 0 is valid).
   * We keep track of the up/down status of the key, and
   * return the keycode if in MEDIUMRAW mode.
   */

  if (up_flag) {
    rep = 0;
    if(!kbd_test_and_clear_bit(keycode, key_down))
        up_flag = kbd_unexpected_up(keycode);
  } else
    rep = kbd_test_and_set_bit(keycode, key_down);

#ifdef CONFIG_MAGIC_SYSRQ    /* Handle the SysRq Hack */
  if (keycode == SYSRQ_KEY) {
    sysrq_pressed = !up_flag;
    return;
  } else if (sysrq_pressed) {
    if (!up_flag && sysrq_enabled)
      handle_sysrq(kbd_sysrq_xlate[keycode], kbd_pt_regs, kbd, tty);
    return;
  }
#endif

  if (kbd->kbdmode == VC_MEDIUMRAW) {
    /* soon keycodes will require more than one byte */
    put_queue(keycode + up_flag);
    raw_mode = 1;  /* Most key classes will be ignored */
  }
  /*
   * Small change in philosophy: earlier we defined repetition by
   *   rep = keycode == prev_keycode;
   *   prev_keycode = keycode;
   * but now by the fact that the depressed key was down already.
   * Does this ever make a difference? Yes.
   */

  /*
   *  Repeat a key only if the input buffers are empty or the
   *  characters get echoed locally. This makes key repeat usable
   *  with slow applications and under heavy loads.
   */
  if (!rep || vc_kbd_mode(kbd,VC_REPEAT) ) {
/*
  ||  (vc_kbd_mode(kbd,VC_REPEAT) && tty &&
       (L_ECHO(tty) || (tty->driver.chars_in_buffer(tty) == 0)))) {
*/
    u_short keysym;
    u_char type;

    /* the XOR below used to be an OR */
    int shift_final = shift_state ^ kbd->lockstate ^ kbd->slockstate;
    ushort *key_map = key_maps[shift_final];

    if (key_map != NULL) {
      keysym = key_map[keycode];
      type = KTYP(keysym);

      if (type >= 0xf0) {
          type -= 0xf0;
          if (raw_mode && ! (TYPES_ALLOWED_IN_RAW_MODE & (1 << type)))
        return;
         if (type == KT_LETTER) {
        type = KT_LATIN;
        if (vc_kbd_led(kbd, VC_CAPSLOCK)) {
            key_map = key_maps[shift_final ^ (1<<KG_SHIFT)];
            if (key_map)
              keysym = key_map[keycode];
        }
          }

          (*key_handler[type])(keysym & 0xff, up_flag);

          if (type != KT_SLOCK)
            kbd->slockstate = 0;

      } else {
          /* maybe only if (kbd->kbdmode == VC_UNICODE) ? */
          if (!up_flag && !raw_mode)
            to_utf8(keysym);
      }
    } else {
      /* maybe beep? */
      /* we have at least to update shift_state */
#if 1      /* how? two almost equivalent choices follow */
      compute_shiftstate();
#else
      keysym = U(plain_map[keycode]);
      type = KTYP(keysym);
      if (type == KT_SHIFT)
        (*key_handler[type])(keysym & 0xff, up_flag);
#endif
    }
  }
}

static void ( *driver_input_handler_kbd )( void *, unsigned short, unsigned long ) = 0;
/*
 */
void kbd_set_driver_handler(
  void ( *handler )( void *, unsigned short, unsigned long )
)
{
  driver_input_handler_kbd = handler;
}

static void put_queue(int ch)
{
  if ( driver_input_handler_kbd ) {
    driver_input_handler_kbd(  ( void *)kbd, (unsigned short)ch,  0 );
  } else {
    add_to_queue( ch );
  }
}

static void puts_queue(char *cp)
{
  while (*cp) {
     put_queue( *cp );
    cp++;
  }
}

static void applkey(int key, char mode)
{
  static char buf[] = { 0x1b, 'O', 0x00, 0x00 };

  buf[1] = (mode ? 'O' : '[');
  buf[2] = key;
  puts_queue(buf);
}

static void enter(void)
{
  if (diacr) {
    put_queue(diacr);
    diacr = 0;
  }
  put_queue(13);

  if (vc_kbd_mode(kbd,VC_CRLF))
    put_queue(10);
}

static void caps_toggle(void)
{
  if (rep)
    return;
  chg_vc_kbd_led(kbd, VC_CAPSLOCK);
}

static void caps_on(void)
{
  if (rep)
    return;
  set_vc_kbd_led(kbd, VC_CAPSLOCK);
}

static void show_ptregs(void)
{
}

static void hold(void)
{
  if (rep )
    return;
   chg_vc_kbd_led(kbd, VC_SCROLLOCK );
}

static void num(void)
{
  if (vc_kbd_mode(kbd,VC_APPLIC))
    applkey('P', 1);
  else
    bare_num();
}

/*
 * Bind this to Shift-NumLock if you work in application keypad mode
 * but want to be able to change the NumLock flag.
 * Bind this to NumLock if you prefer that the NumLock key always
 * changes the NumLock flag.
 */
static void bare_num(void)
{
  if (!rep)
    chg_vc_kbd_led(kbd,VC_NUMLOCK);
}

static void lastcons(void)
{
}

static void decr_console(void)
{
}

static void incr_console(void)
{
}

static void send_intr(void)
{
}

static void scroll_forw(void)
{
}

static void scroll_back(void)
{
}

static void compose(void)
{
  dead_key_next = 1;
}

int spawnpid, spawnsig;

static void spawn_console(void)
{
}

static void SAK(void)
{
}

static void do_ignore(unsigned char value, char up_flag)
{
}

static void do_null()
{
  compute_shiftstate();
}

static void do_spec(unsigned char value, char up_flag)
{
  if (up_flag)
    return;
  if (value >= SIZE(spec_fn_table))
    return;

  if ((kbd->kbdmode == VC_RAW || kbd->kbdmode == VC_MEDIUMRAW) &&
      !(SPECIALS_ALLOWED_IN_RAW_MODE & (1 << value)))
    return;

  spec_fn_table[value]();
}

static void do_lowercase(unsigned char value, char up_flag)
{
}

static void do_self(unsigned char value, char up_flag)
{
  if (up_flag)
    return;    /* no action, if this is a key release */

  if (diacr)
    value = handle_diacr(value);

  if (dead_key_next) {
    dead_key_next = 0;
    diacr = value;
    return;
  }
  put_queue(value);
}

#define A_GRAVE  '`'
#define A_ACUTE  '\''
#define A_CFLEX  '^'
#define A_TILDE  '~'
#define A_DIAER  '"'
#define A_CEDIL  ','
static unsigned char ret_diacr[NR_DEAD] =
  {A_GRAVE, A_ACUTE, A_CFLEX, A_TILDE, A_DIAER, A_CEDIL };

/* Obsolete - for backwards compatibility only */
static void do_dead(unsigned char value, char up_flag)
{
  value = ret_diacr[value];
   printk( " do_dead( %X ) ", value );
  do_dead2(value,up_flag);
}

/*
 * Handle dead key. Note that we now may have several
 * dead keys modifying the same character. Very useful
 * for Vietnamese.
 */
static void do_dead2(unsigned char value, char up_flag)
{
  if (up_flag)
    return;
  diacr = (diacr ? handle_diacr(value) : value);
}

/*
 * We have a combining character DIACR here, followed by the character CH.
 * If the combination occurs in the table, return the corresponding value.
 * Otherwise, if CH is a space or equals DIACR, return DIACR.
 * Otherwise, conclude that DIACR was not combining after all,
 * queue it and return CH.
 */
unsigned char handle_diacr(unsigned char ch)
{
  int d = diacr;
  int i;

  diacr = 0;

  for (i = 0; i < accent_table_size; i++) {
    if (accent_table[i].diacr == d && accent_table[i].base == ch)
      return accent_table[i].result;
  }
  if (ch == ' ' || ch == d)
    return d;

  put_queue(d);
  return ch;
}

static void do_cons(unsigned char value, char up_flag)
{
  if (up_flag)
    return;
}

static void do_fn(unsigned char value, char up_flag)
{
  if (up_flag)
    return;

  if (value < SIZE(func_table)) {
    if (func_table[value])
      puts_queue(func_table[value]);
  } else
    printk( "do_fn called with value=%d\n", value);
}

static void do_pad(unsigned char value, char up_flag)
{
  static const char *pad_chars = "0123456789+-*/\015,.?()";
  static const char *app_map = "pqrstuvwxylSRQMnnmPQ";

  if (up_flag)
    return;    /* no action, if this is a key release */

  /* kludge... shift forces cursor/number keys */
  if (vc_kbd_mode(kbd,VC_APPLIC) && !k_down[KG_SHIFT]) {
    applkey(app_map[value], 1);
    return;
  }
  if (!vc_kbd_led(kbd,VC_NUMLOCK))
    switch (value) {
      case KVAL(K_PCOMMA):
      case KVAL(K_PDOT):
        do_fn(KVAL(K_REMOVE), 0);
        return;
      case KVAL(K_P0):
        do_fn(KVAL(K_INSERT), 0);
        return;
      case KVAL(K_P1):
        do_fn(KVAL(K_SELECT), 0);
        return;
      case KVAL(K_P2):
        do_cur(KVAL(K_DOWN), 0);
        return;
      case KVAL(K_P3):
        do_fn(KVAL(K_PGDN), 0);
        return;
      case KVAL(K_P4):
        do_cur(KVAL(K_LEFT), 0);
        return;
      case KVAL(K_P6):
        do_cur(KVAL(K_RIGHT), 0);
        return;
      case KVAL(K_P7):
        do_fn(KVAL(K_FIND), 0);
        return;
      case KVAL(K_P8):
        do_cur(KVAL(K_UP), 0);
        return;
      case KVAL(K_P9):
        do_fn(KVAL(K_PGUP), 0);
        return;
      case KVAL(K_P5):
        applkey('G', vc_kbd_mode(kbd, VC_APPLIC));
        return;
    }

  put_queue(pad_chars[value]);

  if (value == KVAL(K_PENTER) && vc_kbd_mode(kbd, VC_CRLF))
    put_queue(10);

}

static void do_cur(unsigned char value, char up_flag)
{
  static const char *cur_chars = "BDCA";
  if (up_flag)
    return;

  applkey(cur_chars[value], vc_kbd_mode(kbd,VC_CKMODE));
}

static void do_shift(unsigned char value, char up_flag)
{
  int old_state = shift_state;

  if (rep)
    return;

  /* Mimic typewriter:
     a CapsShift key acts like Shift but undoes CapsLock */
  if (value == KVAL(K_CAPSSHIFT)) {
    value = KVAL(K_SHIFT);
    if (!up_flag)
      clr_vc_kbd_led(kbd, VC_CAPSLOCK);
  }

  if (up_flag) {
    /* handle the case that two shift or control
       keys are depressed simultaneously */
    if (k_down[value])
      k_down[value]--;
  } else
    k_down[value]++;

  if (k_down[value])
    shift_state |= (1 << value);
  else
    shift_state &= ~ (1 << value);

  /* kludge */
  if (up_flag && shift_state != old_state && npadch != -1) {
    if (kbd->kbdmode == VC_UNICODE)
      to_utf8(npadch & 0xffff);
    else
     put_queue(npadch & 0xff);
    npadch = -1;
  }
}

/* called after returning from RAW mode or when changing consoles -
   recompute k_down[] and shift_state from key_down[] */
/* maybe called when keymap is undefined, so that shiftkey release is seen */
void compute_shiftstate(void)
{
  int i, j, k, sym, val;

  shift_state = 0;
  for(i=0; i < SIZE(k_down); i++)
    k_down[i] = 0;

  for(i=0; i < SIZE(key_down); i++)
    if(atomic_load(key_down + i)) {  /* skip this word if not a single bit on */
      k = i*KBD_BITS_PER_ELEMENT;
      for(j=0; j<KBD_BITS_PER_ELEMENT; j++,k++)
        if(kbd_test_bit(k, key_down)) {
    sym = U(plain_map[k]);
    if(KTYP(sym) == KT_SHIFT) {
      val = KVAL(sym);
      if (val == KVAL(K_CAPSSHIFT))
        val = KVAL(K_SHIFT);
      k_down[val]++;
      shift_state |= (1<<val);
    }
        }
    }
}

static void do_meta(unsigned char value, char up_flag)
{
  if (up_flag)
    return;

  if (vc_kbd_mode(kbd, VC_META)) {
    put_queue('\033');
    put_queue(value);
  } else
    put_queue(value | 0x80);
}

static void do_ascii(unsigned char value, char up_flag)
{
  int base;

  if (up_flag)
    return;

  if (value < 10)    /* decimal input of code, while Alt depressed */
      base = 10;
  else {       /* hexadecimal input of code, while AltGr depressed */
      value -= 10;
      base = 16;
  }

  if (npadch == -1)
    npadch = value;
  else
    npadch = npadch * base + value;
}

static void do_lock(unsigned char value, char up_flag)
{
  if (up_flag || rep)
    return;
  chg_vc_kbd_lock(kbd, value);
}

static void do_slock(unsigned char value, char up_flag)
{
  if (up_flag || rep)
    return;

  chg_vc_kbd_slock(kbd, value);
}

/*
 * The leds display either (i) the status of NumLock, CapsLock, ScrollLock,
 * or (ii) whatever pattern of lights people want to show using KDSETLED,
 * or (iii) specified bits of specified words in kernel memory.
 */

static unsigned char ledstate = 0xff; /* undefined */
static unsigned char ledioctl;

unsigned char getledstate(void) {
  return ledstate;
}

void setledstate(struct kbd_struct *kbd, unsigned int led) {
  if (!(led & ~7)) {
    ledioctl = led;
     kbd->ledmode = LED_SHOW_IOCTL;
  } else
    ;
  kbd->ledmode = LED_SHOW_FLAGS;
  set_leds();
}

static struct ledptr {
  unsigned int *addr;
  unsigned int mask;
  unsigned char valid:1;
} ledptrs[3];

void register_leds(
  int console,
  unsigned int led,
  unsigned int *addr,
  unsigned int mask
)
{
  struct kbd_struct *kbd = kbd_table + console;

  if (led < 3) {
    ledptrs[led].addr = addr;
    ledptrs[led].mask = mask;
    ledptrs[led].valid = 1;
    kbd->ledmode = LED_SHOW_MEM;
  } else
    kbd->ledmode = LED_SHOW_FLAGS;
}

static inline unsigned char getleds(void)
{

    struct kbd_struct *kbd = kbd_table + fg_console;

    unsigned char leds;

    if (kbd->ledmode == LED_SHOW_IOCTL)
      return ledioctl;
    leds = kbd->ledflagstate;
    if (kbd->ledmode == LED_SHOW_MEM) {
  if (ledptrs[0].valid) {
      if (*ledptrs[0].addr & ledptrs[0].mask)
        leds |= 1;
      else
        leds &= ~1;
  }
  if (ledptrs[1].valid) {
      if (*ledptrs[1].addr & ledptrs[1].mask)
        leds |= 2;
      else
        leds &= ~2;
  }
  if (ledptrs[2].valid) {
      if (*ledptrs[2].addr & ledptrs[2].mask)
        leds |= 4;
      else
        leds &= ~4;
  }
    }
   return leds;
}

/*
 * This routine is the bottom half of the keyboard interrupt
 * routine, and runs with all interrupts enabled. It does
 * console changing, led setting and copy_to_cooked, which can
 * take a reasonably long time.
 *
 * Aside from timing (which isn't really that important for
 * keyboard interrupts as they happen often), using the software
 * interrupt routines for this thing allows us to easily mask
 * this when we don't want any of the above to happen. Not yet
 * used, but this allows for easy and efficient race-condition
 * prevention later on.
 */
static void kbd_bh(void)
{
  unsigned char leds = getleds();
  if (leds != ledstate) {
    ledstate = leds;
    kbd_leds(leds);
  }
}

void set_leds(void)
{
  kbd_bh();
}

int kbd_init(void)
{

  int i;
  struct kbd_struct kbd0;
  kbd0.ledflagstate = kbd0.default_ledflagstate = KBD_DEFLEDS;
   kbd0.ledmode = LED_SHOW_MEM;
  kbd0.lockstate = KBD_DEFLOCK;
  kbd0.slockstate = 0;
  kbd0.modeflags = KBD_DEFMODE;
  kbd0.kbdmode = VC_XLATE;

  for (i = 0 ; i < MAX_NR_CONSOLES ; i++)
    kbd_table[i] = kbd0;

  kbd_init_hw();
  mark_bh(KEYBOARD_BH);
  return 0;
}
