/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed 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.
 */

#define _XOPEN_SOURCE 700

#include <fcntl.h>
#include <stdio.h>
#include <dirent.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <sys/poll.h>
#include <sys/stat.h>
#include <sys/types.h>

#include <linux/input.h>

#include "minui.h"

#define MAX_DEVICES	16
#define MAX_MISC_FDS	16

#define BITS_PER_LONG		(sizeof(unsigned long) * 8)
#define BITS_TO_LONGS(x)	(((x) + BITS_PER_LONG - 1) / BITS_PER_LONG)

#define test_bit(bit, array) \
	((array)[(bit) / BITS_PER_LONG] & (1 << ((bit) % BITS_PER_LONG)))

struct fd_info {
	ev_callback cb;
	void *data;
};

static struct pollfd ev_fds[MAX_DEVICES + MAX_MISC_FDS];
static struct fd_info ev_fdinfo[MAX_DEVICES + MAX_MISC_FDS];

static unsigned ev_count = 0;
static unsigned ev_dev_count = 0;
static unsigned ev_misc_count = 0;

/* ------------------------------------------------------------------------ */

int
ev_init(ev_callback input_cb, void *data)
{
	DIR *dir;
	struct dirent *de;
	int fd;

	if ((dir = opendir("/dev/input"))) {
		while ((de = readdir(dir))) {
			unsigned long ev_bits[BITS_TO_LONGS(EV_MAX)];

/*			fprintf(stderr,"/dev/input/%s\n", de->d_name);*/
			if (strncmp(de->d_name, "event", 5))
				continue;

			if ((fd = openat(dirfd(dir), de->d_name,
					 O_RDONLY)) < 0)
				continue;

			/* read the evbits of the input device */
			if (ioctl(fd, EVIOCGBIT(0, sizeof(ev_bits)),
				  ev_bits) < 0) {
				close(fd);
				continue;
			}

			/* TODO: add ability to specify event masks. For now,
			 * just assume that only EV_KEY and EV_REL event types
			 * are ever needed. */
			if (!test_bit(EV_KEY, ev_bits) &&
			    !test_bit(EV_REL, ev_bits)) {
				close(fd);
				continue;
			}

			ev_fds[ev_count].fd = fd;
			ev_fds[ev_count].events = POLLIN;
			ev_fdinfo[ev_count].cb = input_cb;
			ev_fdinfo[ev_count].data = data;
			ev_count++;
			ev_dev_count++;
			if (ev_dev_count == MAX_DEVICES)
				break;
		}
	}

	return 0;
}

/* ------------------------------------------------------------------------ */

int
ev_add_fd(int fd, ev_callback cb, void *data)
{
	if (ev_misc_count == MAX_MISC_FDS || !cb)
		return -1;

	ev_fds[ev_count].fd = fd;
	ev_fds[ev_count].events = POLLIN;
	ev_fdinfo[ev_count].cb = cb;
	ev_fdinfo[ev_count].data = data;
	ev_count++;
	ev_misc_count++;
	return 0;
}

/* ------------------------------------------------------------------------ */

void
ev_exit(void)
{
	while (ev_count > 0)
		close(ev_fds[--ev_count].fd);

	ev_misc_count = 0;
	ev_dev_count = 0;
}

/* ------------------------------------------------------------------------ */

int
ev_wait(int timeout)
{
	int r;

	r = poll(ev_fds, ev_count, timeout);
	if (r <= 0)
		return -1;

	return 0;
}

/* ------------------------------------------------------------------------ */

void
ev_dispatch(void)
{
	unsigned n;

	for (n = 0; n < ev_count; n++) {
		ev_callback cb = ev_fdinfo[n].cb;
		if (cb && (ev_fds[n].revents & ev_fds[n].events))
			cb(ev_fds[n].fd, ev_fds[n].revents,
			   ev_fdinfo[n].data);
	}
}

/* ------------------------------------------------------------------------ */

int
ev_get_input(int fd, short revents, struct input_event *ev)
{
	int r;

	if (revents & POLLIN) {
		r = read(fd, ev, sizeof(*ev));
		if (r == sizeof(*ev))
			return 0;
	}

	return -1;
}

/* ------------------------------------------------------------------------ */

int
ev_sync_key_state(ev_set_key_callback set_key_cb, void *data)
{
	unsigned long key_bits[BITS_TO_LONGS(KEY_MAX)];
	unsigned long ev_bits[BITS_TO_LONGS(EV_MAX)];
	unsigned i;
	int ret;

	for (i = 0; i < ev_dev_count; i++) {
		int code;

		memset(key_bits, 0, sizeof(key_bits));
		memset(ev_bits, 0, sizeof(ev_bits));

		ret = ioctl(ev_fds[i].fd, EVIOCGBIT(0, sizeof(ev_bits)),
			    ev_bits);
		if (ret < 0 || !test_bit(EV_KEY, ev_bits))
			continue;

		ret = ioctl(ev_fds[i].fd, EVIOCGKEY(sizeof(key_bits)),
			    key_bits);
		if (ret < 0)
			continue;

		for (code = 0; code <= KEY_MAX; code++)
			if (test_bit(code, key_bits))
				set_key_cb(code, 1, data);
	}

	return 0;
}
