/****************************************************************************
 * drivers/input/keyboard_upper.c
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance with the
 * License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <assert.h>
#include <nuttx/debug.h>
#include <fcntl.h>
#include <poll.h>

#include <nuttx/input/keyboard.h>
#include <nuttx/input/kbd_codec.h>
#include <nuttx/streams.h>
#include <nuttx/kmalloc.h>
#include <nuttx/list.h>
#include <nuttx/circbuf.h>
#include <nuttx/mutex.h>

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

#ifdef CONFIG_INPUT_KEYBOARD_BYTESTREAM

/* The longest sequence that one event can produce in the byte stream.  A
 * normal key is a single byte; a special key is the four byte escape
 * sequence emitted by kbd_specpress().
 */

#  define KEYBOARD_BYTESTREAM_MAX 4
#endif

/****************************************************************************
 * Private Types
 ****************************************************************************/

struct keyboard_opriv_s
{
  sem_t              waitsem;
  mutex_t            lock;
  struct circbuf_s   circ;
  struct list_node   node;
  FAR struct pollfd *fds;
};

/* This structure is for keyboard upper half driver */

struct keyboard_upperhalf_s
{
  mutex_t          lock;     /* Manages exclusive access to this structure */
  struct list_node head;     /* Head of list */
  FAR struct keyboard_lowerhalf_s
                  *lower;    /* A pointer of lower half instance */
  uint8_t          nums;     /* Number of buffer */
};

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

static int     keyboard_open(FAR struct file *filep);
static int     keyboard_close(FAR struct file *filep);
static ssize_t keyboard_read(FAR struct file *filep, FAR char *buffer,
                             size_t len);
static ssize_t keyboard_write(FAR struct file *filep, FAR const char *buffer,
                              size_t len);
static int     keyboard_poll(FAR struct file *filep, FAR struct pollfd *fds,
                             bool setup);

/****************************************************************************
 * Private Data
 ****************************************************************************/

static const struct file_operations g_keyboard_fops =
{
  keyboard_open,  /* open */
  keyboard_close, /* close */
  keyboard_read,  /* read */
  keyboard_write, /* write */
  NULL,           /* seek */
  NULL,           /* ioctl */
  NULL,           /* mmap */
  NULL,           /* truncate */
  keyboard_poll   /* poll */
};

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: keyboard_open
 ****************************************************************************/

static int keyboard_open(FAR struct file *filep)
{
  FAR struct keyboard_opriv_s     *opriv = NULL;
  FAR struct inode                *inode = filep->f_inode;
  FAR struct keyboard_upperhalf_s *upper = inode->i_private;
  int ret;

  ret = nxmutex_lock(&upper->lock);
  if (ret < 0)
    {
      return ret;
    }

  opriv = kmm_zalloc(sizeof(FAR struct keyboard_opriv_s));
  if (opriv == NULL)
    {
      nxmutex_unlock(&upper->lock);
      return -ENOMEM;
    }

  /* Initializes the buffer for each open file */

  ret = circbuf_init(&opriv->circ, NULL,
                     upper->nums * sizeof(struct keyboard_event_s));
  if (ret < 0)
    {
      kmm_free(opriv);
      nxmutex_unlock(&upper->lock);
      return ret;
    }

  /* Perform the operations required by the lower level */

  if (upper->lower->open)
    {
      ret = upper->lower->open(upper->lower);
      if (ret < 0)
        {
          circbuf_uninit(&opriv->circ);
          kmm_free(opriv);
          nxmutex_unlock(&upper->lock);
          return ret;
        }
    }

  nxsem_init(&opriv->waitsem, 0, 0);
  nxmutex_init(&opriv->lock);
  list_add_tail(&upper->head, &opriv->node);
  filep->f_priv = opriv;

  nxmutex_unlock(&upper->lock);
  return ret;
}

/****************************************************************************
 * Name: keyboard_close
 ****************************************************************************/

static int keyboard_close(FAR struct file *filep)
{
  FAR struct keyboard_opriv_s     *opriv = filep->f_priv;
  FAR struct inode                *inode = filep->f_inode;
  FAR struct keyboard_upperhalf_s *upper = inode->i_private;
  int ret;

  ret = nxmutex_lock(&upper->lock);
  if (ret < 0)
    {
      return ret;
    }

  /* Perform the operations required by the lower level */

  if (upper->lower->close)
    {
      ret = upper->lower->close(upper->lower);
      if (ret < 0)
        {
          goto out;
        }
    }

  list_delete(&opriv->node);
  circbuf_uninit(&opriv->circ);
  nxsem_destroy(&opriv->waitsem);
  nxmutex_destroy(&opriv->lock);
  kmm_free(opriv);

out:
  nxmutex_unlock(&upper->lock);
  return ret;
}

/****************************************************************************
 * Name: keyboard_read
 ****************************************************************************/

static ssize_t keyboard_read(FAR struct file *filep,
                             FAR char *buff, size_t len)
{
  FAR struct keyboard_opriv_s *opriv = filep->f_priv;
  int ret;

  /* Make sure that we have exclusive access to the private data structure */

  ret = nxmutex_lock(&opriv->lock);
  if (ret < 0)
    {
      return ret;
    }

  /* Is there keyboard data now? */

  while (circbuf_is_empty(&opriv->circ))
    {
      if ((filep->f_oflags & O_NONBLOCK) != 0)
        {
          ret = -EAGAIN;
          goto out;
        }
      else
        {
          nxmutex_unlock(&opriv->lock);
          ret = nxsem_wait_uninterruptible(&opriv->waitsem);
          if (ret < 0)
            {
              return ret;
            }

          ret = nxmutex_lock(&opriv->lock);
          if (ret < 0)
            {
              return ret;
            }
        }
    }

  ret = circbuf_read(&opriv->circ, buff, len);

out:
  nxmutex_unlock(&opriv->lock);
  return ret;
}

/****************************************************************************
 * Name: keyboard_poll
 ****************************************************************************/

static int keyboard_poll(FAR struct file *filep,
                         FAR struct pollfd *fds, bool setup)
{
  FAR struct keyboard_opriv_s *opriv = filep->f_priv;
  int ret;

  ret = nxmutex_lock(&opriv->lock);
  if (ret < 0)
    {
      return ret;
    }

  if (setup)
    {
      if (opriv->fds == NULL)
        {
          opriv->fds = fds;
          fds->priv  = &opriv->fds;
        }
      else
        {
          ret = -EBUSY;
          goto errout;
        }

      if (!circbuf_is_empty(&opriv->circ))
        {
          poll_notify(&fds, 1, POLLIN);
        }
    }
  else
    {
      opriv->fds = NULL;
      fds->priv  = NULL;
    }

errout:
  nxmutex_unlock(&opriv->lock);
  return ret;
}

/****************************************************************************
 * Name: keyboard_write
 ****************************************************************************/

static ssize_t keyboard_write(FAR struct file *filep,
                              FAR const char *buffer, size_t buflen)
{
  FAR struct inode                *inode = filep->f_inode;
  FAR struct keyboard_upperhalf_s *upper = inode->i_private;
  FAR struct keyboard_lowerhalf_s *lower = upper->lower;

  if (lower->write != NULL)
    {
      return lower->write(lower, buffer, buflen);
    }

  return -ENOSYS;
}

/****************************************************************************
 * Public Function
 ****************************************************************************/

/****************************************************************************
 * Name: keyboard_register
 ****************************************************************************/

int keyboard_register(FAR struct keyboard_lowerhalf_s *lower,
                      FAR const char *path, uint8_t nums)
{
  FAR struct keyboard_upperhalf_s *upper;
  int ret;

  iinfo("Registering %s\n", path);
  if (lower == NULL)
    {
      ierr("ERROR: invalid touchscreen device\n");
      return -EINVAL;
    }

  upper = kmm_zalloc(sizeof(struct keyboard_upperhalf_s));
  if (upper == NULL)
    {
      ierr("ERROR: Failed to mem alloc!\n");
      return -ENOMEM;
    }

  upper->lower = lower;
  upper->nums  = nums;
  lower->priv  = upper;
  list_initialize(&upper->head);
  nxmutex_init(&upper->lock);

  ret = register_driver(path, &g_keyboard_fops, 0600, upper);
  if (ret < 0)
    {
      nxmutex_destroy(&upper->lock);
      kmm_free(upper);
      return ret;
    }

  return ret;
}

/****************************************************************************
 * Name: keyboard_unregister
 ****************************************************************************/

int keyboard_unregister(FAR struct keyboard_lowerhalf_s *lower,
                        FAR const char *path)
{
  FAR struct keyboard_upperhalf_s *upper;
  int ret;

  DEBUGASSERT(lower != NULL);
  DEBUGASSERT(lower->priv != NULL);

  upper = lower->priv;

  iinfo("UnRegistering %s\n", path);
  ret = unregister_driver(path);
  if (ret < 0)
    {
      return ret;
    }

  nxmutex_destroy(&upper->lock);
  kmm_free(upper);
  return 0;
}

/****************************************************************************
 * Name: keyboard_encode
 *
 * Description:
 *   Render one keyboard event as the byte stream that the keyboard codec
 *   defines, for applications that consume characters rather than events.
 *
 *   Only the press events are rendered.  A byte stream has no way to say
 *   that a key came up:  a normal key contributes its character and nothing
 *   more, which is what a keyboard reporting through a character device has
 *   always delivered.  An application that needs key releases has to read
 *   the events instead.
 *
 * Input Parameters:
 *   stream  - Memory stream to render into
 *   buf     - Buffer of KEYBOARD_BYTESTREAM_MAX bytes backing the stream
 *   keycode - The key
 *   type    - The event type
 *
 * Returned Value:
 *   The number of bytes rendered, zero if this event has no representation
 *   in the byte stream.
 *
 ****************************************************************************/

#ifdef CONFIG_INPUT_KEYBOARD_BYTESTREAM
static size_t keyboard_encode(FAR struct lib_memoutstream_s *stream,
                              FAR char *buf, uint32_t keycode, uint32_t type)
{
  lib_memoutstream(stream, buf, KEYBOARD_BYTESTREAM_MAX);

  switch (type)
    {
      case KEYBOARD_PRESS:
        kbd_press(keycode, &stream->common);
        break;

      case KEYBOARD_SPECPRESS:

        /* Out of range keycodes would trip an assertion in the codec.  A
         * lower half that reports something the codec does not know about
         * simply does not appear in the byte stream.
         */

        if (keycode < FIRST_KEYCODE || keycode > LAST_KEYCODE)
          {
            return 0;
          }

        kbd_specpress(keycode, &stream->common);
        break;

      default:
        return 0;
    }

  return stream->common.nput;
}
#endif

/****************************************************************************
 * keyboard_event
 ****************************************************************************/

void keyboard_event(FAR struct keyboard_lowerhalf_s *lower, uint32_t keycode,
                    uint32_t type)
{
  FAR struct keyboard_upperhalf_s *upper = lower->priv;
  FAR struct keyboard_opriv_s     *opriv;
  int semcount;

#ifdef CONFIG_INPUT_KEYBOARD_BYTESTREAM
  struct lib_memoutstream_s stream;
  char buf[KEYBOARD_BYTESTREAM_MAX];
  size_t buflen;

  buflen = keyboard_encode(&stream, buf, keycode, type);
  if (buflen == 0)
    {
      /* This event has no representation in the byte stream */

      return;
    }
#else
  struct keyboard_event_s key;

  key.code = keycode;
  key.type = type;
#endif

  if (nxmutex_lock(&upper->lock) < 0)
    {
      return;
    }

  list_for_every_entry(&upper->head, opriv, struct keyboard_opriv_s, node)
    {
      if (nxmutex_lock(&opriv->lock) == 0)
        {
#ifdef CONFIG_INPUT_KEYBOARD_BYTESTREAM
          circbuf_overwrite(&opriv->circ, buf, buflen);
#else
          circbuf_overwrite(&opriv->circ, &key,
                            sizeof(struct keyboard_event_s));
#endif
          nxsem_get_value(&opriv->waitsem, &semcount);
          if (semcount < 1)
            {
              nxsem_post(&opriv->waitsem);
            }

          poll_notify(&opriv->fds, 1, POLLIN);
          nxmutex_unlock(&opriv->lock);
        }
    }

  nxmutex_unlock(&upper->lock);
}