/**
 * Copyright (c) 2017 rxi
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the MIT license. See LICENSE for details.
 */

#include <stdlib.h>
#include <string.h>
#include <pc.h>
#include <conio.h>
#include <dpmi.h>
#include "luaobj.h"
#include "keyboard.h"
#include "event.h"

#define KEY_MAX 128
#define BUFFER_SIZE 32
#define BUFFER_MASK (BUFFER_SIZE - 1)

static const char *scancodeMap[] = {
    [0] = "?",        [1] = "escape",     [2] = "1",           [3] = "2",
    [4] = "3",        [5] = "4",          [6] = "5",           [7] = "6",
    [8] = "7",        [9] = "8",          [10] = "9",          [11] = "0",
    [12] = "-",       [13] = "=",         [14] = "backspace",  [15] = "tab",
    [16] = "q",       [17] = "w",         [18] = "e",          [19] = "r",
    [20] = "t",       [21] = "y",         [22] = "u",          [23] = "i",
    [24] = "o",       [25] = "p",         [26] = "[",          [27] = "]",
    [28] = "return",  [29] = "lctrl",     [30] = "a",          [31] = "s",
    [32] = "d",       [33] = "f",         [34] = "g",          [35] = "h",
    [36] = "j",       [37] = "k",         [38] = "l",          [39] = ";",
    [40] = "\"",      [41] = "`",         [42] = "lshift",     [43] = "\\",
    [44] = "z",       [45] = "x",         [46] = "c",          [47] = "v",
    [48] = "b",       [49] = "n",         [50] = "m",          [51] = ",",
    [52] = ".",       [53] = "/",         [54] = "rshift",     [55] = "*",
    [56] = "lalt",    [57] = "space",     [58] = "capslock",   [59] = "f1",
    [60] = "f2",      [61] = "f3",        [62] = "f4",         [63] = "f5",
    [64] = "f6",      [65] = "f7",        [66] = "f8",         [67] = "f9",
    [68] = "f10",     [69] = "numlock",   [70] = "scrolllock", [71] = "home",
    [72] = "up",      [73] = "pageup",    [74] = "-",          [75] = "left",
    [76] = "5",       [77] = "right",     [78] = "+",          [79] = "end",
    [80] = "down",    [81] = "pagedown",  [82] = "insert",     [83] = "delete",
    [84] = "?",       [85] = "?",         [86] = "?",          [87] = "?",
    [88] = "f12",     [89] = "?",         [90] = "?",          [91] = "?",
    [92] = "?",       [93] = "?",         [94] = "?",          [95] = "?",
    [96] = "enter",   [97] = "lctrl",     [98] = "/",          [99] = "f12",
    [100] = "rctrl",  [101] = "pause",    [102] = "home",      [103] = "up",
    [104] = "pageup", [105] = "left",     [106] = "right",     [107] = "end",
    [108] = "down",   [109] = "pagedown", [110] = "insert",    [111] = "?",
    [112] = "?",      [113] = "?",        [114] = "?",         [115] = "?",
    [116] = "?",      [117] = "?",        [118] = "?",         [119] = "pause",
    [120] = "?",      [121] = "?",        [122] = "?",         [123] = "?",
    [124] = "?",      [125] = "?",        [126] = "?",         [127] = "?",
    [128] = NULL,
};

volatile int keyboard_allowKeyRepeat = 0;
volatile char keyboard_keyStates[KEY_MAX];

enum { KEYPRESSED, KEYRELEASED };
typedef struct {
  unsigned char type, code, isrepeat;
} key_event_t;

volatile struct {
  key_event_t data[32];
  unsigned readi, writei;
} keyboard_events;

_go32_dpmi_seginfo old_keyb_handler_seginfo, new_keyb_handler_seginfo;

void keyboard_handler() {
  static unsigned char code;
  code = inportb(0x60);

  if (code != 224) {
    volatile key_event_t *e;
    /* Handle key up / down */
    if (code & (1 << 7)) {
      /* Key up */
      code &= ~(1 << 7);
      keyboard_keyStates[code] = 0;
      e = &keyboard_events.data[keyboard_events.writei & BUFFER_MASK];
      e->type = KEYRELEASED;
      e->code = code;
      e->isrepeat = 0;
      keyboard_events.writei++;

    } else {
      /* Key down */
      int isrepeat = keyboard_keyStates[code];
      if (!isrepeat || keyboard_allowKeyRepeat) {
        keyboard_keyStates[code] = 1;
        e = &keyboard_events.data[keyboard_events.writei & BUFFER_MASK];
        e->type = KEYPRESSED;
        e->code = code;
        e->isrepeat = isrepeat;
        keyboard_events.writei++;
      }
    }
  }

  outportb(0x20, 0x20);
}

void keyboard_handler_end() {}

int keyboard_init(void) {
  _go32_dpmi_lock_data((char *)&keyboard_keyStates, KEY_MAX);
  _go32_dpmi_lock_data((char *)&keyboard_events, sizeof(keyboard_events));
  _go32_dpmi_lock_code(keyboard_handler, (unsigned long)keyboard_handler_end -
                                             (unsigned long)keyboard_handler);
  _go32_dpmi_get_protected_mode_interrupt_vector(9, &old_keyb_handler_seginfo);
  new_keyb_handler_seginfo.pm_offset = (int)keyboard_handler;
  _go32_dpmi_chain_protected_mode_interrupt_vector(9,
                                                   &new_keyb_handler_seginfo);
  return 0;
}

void keyboard_deinit(void) {
  _go32_dpmi_set_protected_mode_interrupt_vector(9, &old_keyb_handler_seginfo);
}

void keyboard_setKeyRepeat(int allow) { keyboard_allowKeyRepeat = allow; }

int keyboard_isDown(const char *key) {
  int i;
  for (i = 0; scancodeMap[i]; i++) {
    if (!strcmp(scancodeMap[i], key)) {
      return keyboard_keyStates[i];
    }
  }
  return 0;
}

void keyboard_update(void) {
  /* Handle key press / release */
  while (keyboard_events.readi != keyboard_events.writei) {
    key_event_t ke =
        keyboard_events.data[keyboard_events.readi++ & BUFFER_MASK];
    event_t e;
    if (ke.type == KEYPRESSED) {
      e.type = EVENT_KEYBOARD_PRESSED;
    } else {
      e.type = EVENT_KEYBOARD_RELEASED;
    }
    e.keyboard.key = scancodeMap[ke.code];
    e.keyboard.isrepeat = ke.isrepeat;
    event_push(&e);
  }

  /* Handle text input */
  char buf[64];
  int i = 0;
  while (kbhit()) {
    int chr = getch();
    if (chr == 0) { /* Discard "special" keys */
      getch();
    } else if (chr >= 32) {
      buf[i++] = chr;
    }
  }
  if (i > 0) {
    event_t e;
    e.type = EVENT_KEYBOARD_TEXTINPUT;
    memcpy(e.keyboard.text, buf, i);
    e.keyboard.text[i] = '\0';
    event_push(&e);
  }
}