diff --git a/kilo.c b/kilo.c
index 8365167..2268593 100644
--- a/kilo.c
+++ b/kilo.c
@@ -15,9 +15,21 @@
 
 #define CTRL_KEY(k) ((k) & 0x1f)
 
+enum editorKey
+{
+  ARROW_LEFT = 1000,
+  ARROW_RIGHT,
+  ARROW_UP,
+  ARROW_DOWN,
+  PAGE_UP,
+  PAGE_DOWN
+};
+
 /*** data ***/
 
-struct editorConfig {
+struct editorConfig
+{
+  int cx, cy;
   int screenrows;
   int screencols;
   struct termios orig_termios;
@@ -27,7 +39,8 @@ struct editorConfig E;
 
 /*** terminal ***/
 
-void die(const char *s) {
+void die(const char *s)
+{
   write(STDOUT_FILENO, "\x1b[2J", 4);
   write(STDOUT_FILENO, "\x1b[H", 3);
 
@@ -35,13 +48,16 @@ void die(const char *s) {
   exit(1);
 }
 
-void disableRawMode() {
+void disableRawMode()
+{
   if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E.orig_termios) == 1)
     die("tcsetattr");
 }
 
-void enableRawMode() {
-  if (tcgetattr(STDIN_FILENO, &E.orig_termios) == -1) die("tcgetattr");
+void enableRawMode()
+{
+  if (tcgetattr(STDIN_FILENO, &E.orig_termios) == -1)
+    die("tcgetattr");
   atexit(disableRawMode);
 
   struct termios raw = E.orig_termios;
@@ -53,45 +69,107 @@ void enableRawMode() {
   raw.c_cc[VMIN] = 0;
   raw.c_cc[VTIME] = 1;
 
-  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1) die("tcsetattr");
+  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &raw) == -1)
+    die("tcsetattr");
 }
 
-char editorReadKey() {
+int editorReadKey()
+{
   int nread;
   char c;
-  while ((nread = read(STDIN_FILENO, &c, 1)) != 1) {
-    if (nread == -1 && errno != EAGAIN) die("read");
+  while ((nread = read(STDIN_FILENO, &c, 1)) != 1)
+  {
+    if (nread == -1 && errno != EAGAIN)
+      die("read");
+  }
+
+  if (c == '\x1b')
+  {
+    char seq[3];
+    if (read(STDIN_FILENO, &seq[0], 1) != 1)
+      return '\x1b';
+    if (read(STDIN_FILENO, &seq[1], 1) != 1)
+      return '\x1b';
+
+    if (seq[0] == '[')
+    {
+      if (seq[1] >= '0' && seq[1] <= '9')
+      {
+        if (read(STDIN_FILENO, &seq[2], 1) != 1)
+          return '\x1b';
+        if (seq[2] == '~')
+        {
+          switch (seq[1])
+          {
+          case '5':
+            return PAGE_UP;
+          case '6':
+            return PAGE_DOWN;
+          }
+        }
+      }
+      else
+      {
+        switch (seq[1])
+        {
+        case 'A':
+          return ARROW_UP;
+        case 'B':
+          return ARROW_DOWN;
+        case 'C':
+          return ARROW_RIGHT;
+        case 'D':
+          return ARROW_LEFT;
+        }
+      }
+    }
+    return '\x1b';
+  }
+  else
+  {
+    return c;
   }
-  return c;
 }
 
-int getCursorPosition(int *rows, int *cols) {
+int getCursorPosition(int *rows, int *cols)
+{
   char buf[32];
   unsigned int i = 0;
 
-  if (write(STDOUT_FILENO, "\x1b[6n", 4) != 4) return -1;
+  if (write(STDOUT_FILENO, "\x1b[6n", 4) != 4)
+    return -1;
 
-  while (i < sizeof(buf) - 1) {
-    if(read(STDIN_FILENO, &buf[i], 1) != 1) break;
-    if(buf[i] == 'R') break;
+  while (i < sizeof(buf) - 1)
+  {
+    if (read(STDIN_FILENO, &buf[i], 1) != 1)
+      break;
+    if (buf[i] == 'R')
+      break;
     i++;
   }
   buf[i] = '\0';
 
-  if (buf[0] != '\x1b' || buf[1] != '[') return -1;
-  if (sscanf(&buf[2], "%d;%d", rows, cols) != 2) return -1;
+  if (buf[0] != '\x1b' || buf[1] != '[')
+    return -1;
+  if (sscanf(&buf[2], "%d;%d", rows, cols) != 2)
+    return -1;
 
   return 0;
 }
 
-int getWindowSize(int *rows, int *cols) {
+int getWindowSize(int *rows, int *cols)
+{
   struct winsize ws;
 
-  if (1 || ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1 || ws.ws_col == 0) {
-    if (write(STDOUT_FILENO, "\x1b[999C\x1b[999B", 12) != 12) return -1;
-//    editorReadKey();
+  if (1 || ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == -1 || ws.ws_col == 0)
+  {
+    if (write(STDOUT_FILENO, "\x1b[999C\x1b[999B", 12) != 12)
+      return -1;
+    //    editorReadKey();
     return getCursorPosition(rows, cols);
-  } else {
+  }
+  else
+  {
     *cols = ws.ws_col;
     *rows = ws.ws_row;
     return 0;
@@ -100,95 +178,171 @@ int getWindowSize(int *rows, int *cols) {
 
 /*** append buffer ***/
 
-struct abuf {
+struct abuf
+{
   char *b;
   int len;
 };
 
-#define ABUF_INIT {NULL, 0}
+#define ABUF_INIT \
+  {               \
+    NULL, 0       \
+  }
 
-void abAppend(struct abuf *ab, const char *s, int len) {
+void abAppend(struct abuf *ab, const char *s, int len)
+{
   char *new = realloc(ab->b, ab->len + len);
 
-  if (new == NULL) return;
+  if (new == NULL)
+    return;
   memcpy(&new[ab->len], s, len);
   ab->b = new;
   ab->len += len;
 }
 
-void abFree(struct abuf *ab) {
+void abFree(struct abuf *ab)
+{
   free(ab->b);
 }
 
 /*** output ***/
 
-void editorDrawRows(struct abuf *ab) {
+void editorDrawRows(struct abuf *ab)
+{
   int y;
-  for (y = 0; y < E.screenrows; y++) {
-    if (y == E.screenrows / 3) {
+  for (y = 0; y < E.screenrows; y++)
+  {
+    if (y == E.screenrows / 3)
+    {
       char welcome[80];
       int welcomelen = snprintf(welcome, sizeof(welcome),
                                 "Kilo editor -- version %s", KILO_VERSION);
-      if (welcomelen > E.screencols) welcomelen = E.screencols;
+      if (welcomelen > E.screencols)
+        welcomelen = E.screencols;
       int padding = (E.screencols - welcomelen) / 2;
-      if (padding) {
+      if (padding)
+      {
         abAppend(ab, "~", 1);
         padding--;
       }
-      while (padding--) abAppend(ab, " ", 1);
+      while (padding--)
+        abAppend(ab, " ", 1);
       abAppend(ab, welcome, welcomelen);
-    } else {
+    }
+    else
+    {
       abAppend(ab, "~", 1);
     }
 
     abAppend(ab, "\x1b[K", 3);
-    if (y < E.screenrows - 1) {
+    if (y < E.screenrows - 1)
+    {
       abAppend(ab, "\r\n", 2);
     }
   }
 }
 
-void editorRefreshScreen() {
+void editorRefreshScreen()
+{
   struct abuf ab = ABUF_INIT;
 
   abAppend(&ab, "\x1b[?25l", 6);
-  abAppend(&ab, "\x1b[H" , 3);
-  
+  abAppend(&ab, "\x1b[H", 3);
+
   editorDrawRows(&ab);
 
-  abAppend(&ab, "\x1b[H", 3);
+  char buf[32];
+  snprintf(buf, sizeof(buf), "\x1b[%d;%dH", E.cy + 1, E.cx + 1);
+  abAppend(&ab, buf, strlen(buf));
+
   abAppend(&ab, "\x1b[?25h", 6);
   write(STDOUT_FILENO, ab.b, ab.len);
   abFree(&ab);
 }
 
-
 /*** input ***/
 
-void editorProcessKeypress() {
-  char c = editorReadKey();
+void editorMoveCursor(int key)
+{
+  switch (key)
+  {
+  case ARROW_LEFT:
+    if (E.cx != 0)
+    {
+      E.cx--;
+    }
+    break;
+  case ARROW_RIGHT:
+    if (E.cx != E.screencols - 1)
+    {
+      E.cx++;
+    }
+    break;
 
-  switch (c) {
-    case CTRL_KEY('q'):
-      write(STDOUT_FILENO, "\x1b[2J", 4);
-      write(STDOUT_FILENO, "\x1b[H", 3);
+  case ARROW_UP:
+    if (E.cy != 0)
+    {
+      E.cy--;
+    }
+    break;
+  case ARROW_DOWN:
+    if (E.cy != E.screenrows - 1)
+    {
+      E.cy++;
+    }
+    break;
+  default:
+    break;
+  }
+}
 
-      exit(0);
-      break;
+void editorProcessKeypress()
+{
+  int c = editorReadKey();
+
+  switch (c)
+  {
+  case CTRL_KEY('q'):
+    write(STDOUT_FILENO, "\x1b[2J", 4);
+    write(STDOUT_FILENO, "\x1b[H", 3);
+
+    exit(0);
+    break;
+  case PAGE_UP:
+  case PAGE_DOWN:
+  {
+    int times = E.screenrows;
+    while (times--)
+      editorMoveCursor(c == PAGE_UP ? ARROW_UP : ARROW_DOWN);
+  }
+  break;
+
+  case ARROW_UP:
+  case ARROW_DOWN:
+  case ARROW_LEFT:
+  case ARROW_RIGHT:
+    editorMoveCursor(c);
+    break;
   }
 }
 
 /*** init ***/
 
-void initEditor() {
-  if (getWindowSize(&E.screenrows, &E.screencols) == -1) die("getWindowSize");
+void initEditor()
+{
+  E.cx = 0;
+  E.cy = 0;
+  if (getWindowSize(&E.screenrows, &E.screencols) == -1)
+    die("getWindowSize");
 }
 
-int main() {
+int main()
+{
   enableRawMode();
   initEditor();
 
-  while (1) {
+  while (1)
+  {
     editorRefreshScreen();
     editorProcessKeypress();
   }