#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <unistd.h>
#include <systemd/sd-bus.h>
#include <errno.h>
#include <linux/input.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <libevdev/libevdev.h>

#include "utils.h"
#include "shared.h"
#include "rcm-server-main.h"
#include "rcm-server-evdev.h"
#include "rcm-server-keymap.h"

struct rc_scancode {
	__u16 protocol;
	__u16 reserved[3];
	__u64 scancode;
};

#define INPUT_KEYMAP_BY_INDEX   (1 << 0)
struct rc_keymap_entry {
	__u8  flags;
	__u8  len;
	__u16 index;
	__u32 keycode;
	union {
		struct rc_scancode rc;
		__u8 scancode[32];
	} u;
	char end[];
};
#define RKE_SIZE (sizeof(struct rc_scancode))

static const char *
evdev_guess_protocol(struct device *device, uint64_t scancode, uint32_t keycode)
{
	struct rc_keymap_entry rke;
	unsigned i;

	if (!device || device->evdev_fd < 0)
		return NULL;

	for (i = 0; ; i++) {
		memset(&rke, 0, sizeof(rke));
		rke.len = RKE_SIZE;
		rke.index = i;
		rke.flags = INPUT_KEYMAP_BY_INDEX;
		if (ioctl(device->evdev_fd, EVIOCGKEYCODE_V2, &rke))
			break;

		if (rke.u.rc.scancode != scancode)
			continue;

		if (rke.keycode != keycode)
			continue;

		if (rke.u.rc.protocol > ARRAY_SIZE(rc_protocols))
			return NULL;

		return rc_protocols[rke.u.rc.protocol];
	}

	return NULL;
}

static int
evdev_clear_keymap(struct device *device)
{
	struct rc_keymap_entry rke;
	unsigned count = 0;
	int r = 0;

	printf("Clearing keymap...");
	while (true) {
		memset(&rke, 0, sizeof(rke));
		rke.len = RKE_SIZE;
		rke.index = 0;
		rke.flags = INPUT_KEYMAP_BY_INDEX;
		if (ioctl(device->evdev_fd, EVIOCGKEYCODE_V2, &rke)) {
			printf("done (%u entries removed)\n", count);
			break;
		}

		/*
		printf("  Clearing 0x%08llX (0x%02X) to 0x%02X\n",
		       rke.u.rc.scancode, rke.u.rc.protocol, rke.keycode);
		       */

		rke.keycode = KEY_RESERVED;
		if (ioctl(device->evdev_fd, EVIOCSKEYCODE_V2, &rke)) {
			r = -errno;
			printf("failed (%s)\n", strerror(errno));
			break;
		}
		count++;
	}

	return r;
}

static void
set_keycode_new(struct device *device, __u16 protocol, __u64 scancode, __u32 keycode)
{
	struct rc_keymap_entry rke;

	memset(&rke, 0, sizeof(rke));
	rke.len = RKE_SIZE;
	rke.u.rc.protocol = protocol;
	rke.u.rc.scancode = scancode;
	rke.keycode = keycode;

	printf("Setting keycode (new ioctl) 0x%08llX (0x%02X) to 0x%02X\n",
	       rke.u.rc.scancode, rke.u.rc.protocol, rke.keycode);

	if (ioctl(device->evdev_fd, EVIOCSKEYCODE_V2, &rke)) {
		printf("Unable to call SETKEYCODE2 ioctl\n");
		exit(EXIT_FAILURE);
	}
}

static int
evdev_set_keymap(struct device *device, struct keymap *keymap)
{
	unsigned i;

	printf("\tSetting up keymap: %s\n", keymap->name);

	for (i = 0; i < keymap->keycode_count; i++)
		set_keycode_new(device,
				keymap->keycodes[i].protocol,
				keymap->keycodes[i].scancode,
				keymap->keycodes[i].lik->value);

	printf("\tDone: %u entries added\n", i);
	return 0;
}

static int
evdev_read(sd_event_source *s, int fd, uint32_t revents, void *userdata)
{
	struct device *device = userdata;
	struct input_event ev;
	static struct linux_input_keycode *keycode = NULL;
	static bool pressed = false;
	static uint32_t scancode;
	static bool scancode_recv = false;
	unsigned i;
	int r;

	if (fd != device->evdev_fd)
		fprintf(stderr, "evdev fd mismatch: %i != %i\n", device->evdev_fd, fd);

	if (revents & EPOLLHUP) {
		fprintf(stderr, "evdev connection closed!\n");
		close(fd);
		device->evdev_fd = -1;
		return 0;
	}

	if (!(revents & EPOLLIN)) {
		fprintf(stderr, "unexpected evdev event: %" PRIu32 "\n", revents);
		return 0;
	}

	do {
		r = libevdev_next_event(device->evdev_dev, LIBEVDEV_READ_FLAG_NORMAL, &ev);
		if (r != LIBEVDEV_READ_STATUS_SUCCESS)
			continue;

		printf("Event: %s %s %d\n",
		       libevdev_event_type_get_name(ev.type),
		       libevdev_event_code_get_name(ev.type, ev.code),
		       ev.value);

		switch (ev.type) {
		case EV_KEY:
			if (keycode)
				printf("Reading from evdev - multiple keycodes?\n");

			for (i = 0; linux_input_keycodes[i].name; i++) {
				if (linux_input_keycodes[i].value == ev.code)
					break;
			}

			if (!linux_input_keycodes[i].name) {
				printf("evdev - unknown keycode (%u)\n", ev.code);
				break;
			}

			keycode = &linux_input_keycodes[i];
			if (ev.value)
				pressed = true;
			break;

		case EV_MSC:
			if (ev.code == MSC_SCAN) {
				if (scancode_recv)
					printf("Reading from evdev - multiple scancodes?\n");
				scancode_recv = true;
				scancode = ev.value;
			}
			break;

		case EV_SYN:
			if (keycode || scancode_recv) {
				const char *protocol;

				/* FIXME: protocol reporting needs kernel support */
				if (scancode_recv)
					protocol = evdev_guess_protocol(device, scancode, keycode ? keycode->value : KEY_RESERVED);

				printf("evdev -");

				if (scancode_recv) {
					printf(" protocol %s (guessed)", protocol);
					printf(" scancode 0x%08x", scancode);
				}

				if (keycode) {
					printf(" keycode %s (%u)", keycode->name, keycode->value);
					printf(" %s", pressed ? "pressed" : "released");
				}

				printf("\n");

				if (scancode_recv)
					sd_bus_emit_signal(device->mgr->bus,
							   device->path,
							   "org.gnome.RemoteControlManager.Device",
							   "KeyPressed",
							   "sts", protocol, scancode,
							   keycode ? keycode->name : "KEY_RESERVED");

				else if (keycode && !pressed)
					sd_bus_emit_signal(device->mgr->bus,
							   device->path,
							   "org.gnome.RemoteControlManager.Device",
							   "KeyReleased",
							   "s", keycode->name);
			}

			scancode_recv = false;
			pressed = false;
			keycode = NULL;
			break;

		default:
			break;
		}

	} while (r == LIBEVDEV_READ_STATUS_SUCCESS || r == LIBEVDEV_READ_STATUS_SYNC);

	return 0;
}

int
evdev_setup(struct device *device, const char *path)
{
	int r;
	struct keymap *keymap;

	if (!device)
		return -EINVAL;

	if (device->evdev_fd >= 0) {
		printf("Multiple evdev devices!?\n");
		return 0;
	}

	device->evdev_fd = open(path, O_RDONLY | O_NONBLOCK);
	r = libevdev_new_from_fd(device->evdev_fd, &device->evdev_dev);
	if (r < 0) {
		printf("Failed to open evdev device %s: %s\n", path, strerror(-r));
		close(device->evdev_fd);
		return r;
	}

	printf("Performing evdev setup for device %s (%s)\n",
	       device->path, libevdev_get_name(device->evdev_dev));
	r = evdev_clear_keymap(device);
	if (r < 0)
		return r;

	list_for_each_entry(keymap, &device->keymaps, list)
		r = evdev_set_keymap(device, keymap);

	if (sd_event_add_io(device->mgr->event, &device->evdev_ev,
			    device->evdev_fd, EPOLLIN, evdev_read, device) < 0) {
		printf("Failed to add event source for evdev device %s: %s\n",
		       path, strerror(errno));
		close(device->evdev_fd);
		device->evdev_fd = -1;
		return -errno;
	}

	return r;
}