/*
 * Copyright © 2020 Red Hat, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

#include "config.h"

#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>

#include "util-io.h"
#include "util-macros.h"
#include "util-object.h"
#include "util-sources.h"
#include "util-strings.h"

#include "libei.h"
#include "libei-private.h"
#include "libei-proto.h"
#include "brei-shared.h"

static void
ei_event_destroy(struct ei_event *event)
{
	switch (event->type) {
	case EI_EVENT_CONNECT:
	case EI_EVENT_DISCONNECT:
	case EI_EVENT_DEVICE_ADDED:
	case EI_EVENT_DEVICE_REMOVED:
	case EI_EVENT_DEVICE_SUSPENDED:
	case EI_EVENT_DEVICE_RESUMED:
		break;
	default:
		assert(!"destroy not implemented for this type");
	}
	ei_device_unref(event->device);
}

OBJECT_IMPLEMENT_CREATE(ei_event);
static
OBJECT_IMPLEMENT_REF(ei_event);
_public_
OBJECT_IMPLEMENT_UNREF(ei_event);
_public_
OBJECT_IMPLEMENT_GETTER(ei_event, type, enum ei_event_type);
_public_
OBJECT_IMPLEMENT_GETTER(ei_event, device, struct ei_device*);

static void
ei_disconnect(struct ei *ei);

static void
ei_destroy(struct ei *ei)
{
	ei_disconnect(ei);

	struct ei_event *e;
	while ((e = ei_get_event(ei)) != NULL)
		ei_event_unref(e);

	if (ei->backend_interface.destroy)
		ei->backend_interface.destroy(ei, ei->backend);
	ei->backend = NULL;
	sink_unref(ei->sink);
	free(ei->name);
}

OBJECT_IMPLEMENT_CREATE(ei);
_public_
OBJECT_IMPLEMENT_REF(ei);
_public_
OBJECT_IMPLEMENT_UNREF(ei);
#define _cleanup_ei_ _cleanup_(ei_cleanup)
_public_
OBJECT_IMPLEMENT_SETTER(ei, user_data, void *);
_public_
OBJECT_IMPLEMENT_GETTER(ei, user_data, void *);

_public_ struct ei *
ei_new(void *user_data)
{
	_cleanup_ei_ struct ei *ei = ei_create(NULL);

	ei->state = EI_STATE_NEW;
	list_init(&ei->event_queue);
	list_init(&ei->devices);

	ei_log_set_handler(ei, NULL);
	ei_log_set_priority(ei, EI_LOG_PRIORITY_INFO);
	ei->sink = sink_new();
	if (!ei->sink)
		return NULL;

	ei->user_data = user_data;
	ei->backend = NULL;

	return steal(&ei);
}

_public_ int
ei_get_fd(struct ei *ei)
{
	return sink_get_fd(ei->sink);
}

_public_ void
ei_dispatch(struct ei *ei)
{
	sink_dispatch(ei->sink);
}

static void
ei_queue_event(struct ei *ei, struct ei_event *event)
{
	log_debug(ei, "queuing event type %d\n", event->type);

	list_append(&ei->event_queue, &event->link);
}

static void
ei_queue_connect_event(struct ei *ei)
{
	struct ei_event *e = ei_event_create(&ei->object);
	e->type = EI_EVENT_CONNECT;

	ei_queue_event(ei, e);
}

static void
ei_queue_disconnect_event(struct ei *ei)
{
	struct ei_event *e = ei_event_create(&ei->object);
	e->type = EI_EVENT_DISCONNECT;

	ei_queue_event(ei, e);
}

static void
ei_queue_added_event(struct ei_device *device)
{
	struct ei *ei= ei_device_get_context(device);

	struct ei_event *e = ei_event_create(&ei->object);
	e->type = EI_EVENT_DEVICE_ADDED;
	e->device = ei_device_ref(device);

	ei_queue_event(ei, e);
}

static void
ei_queue_removed_event(struct ei_device *device)
{
	struct ei *ei= ei_device_get_context(device);

	struct ei_event *e = ei_event_create(&ei->object);
	e->type = EI_EVENT_DEVICE_REMOVED;
	e->device = ei_device_ref(device);

	ei_queue_event(ei, e);
}

static void
ei_queue_suspended_event(struct ei_device *device)
{
	struct ei *ei= ei_device_get_context(device);

	struct ei_event *e = ei_event_create(&ei->object);
	e->type = EI_EVENT_DEVICE_SUSPENDED;
	e->device = ei_device_ref(device);

	ei_queue_event(ei, e);
}

static void
ei_queue_resumed_event(struct ei_device *device)
{
	struct ei *ei= ei_device_get_context(device);

	struct ei_event *e = ei_event_create(&ei->object);
	e->type = EI_EVENT_DEVICE_RESUMED;
	e->device = ei_device_ref(device);

	ei_queue_event(ei, e);
}

static int
connection_send_connect(struct ei *ei)
{
	if (ei->state == EI_STATE_NEW ||
	    ei->state == EI_STATE_DISCONNECTED)
		return 0;

	return ei_proto_send_connect(ei);
}

static int
connection_send_disconnect(struct ei *ei)
{
	if (ei->state == EI_STATE_NEW ||
	    ei->state == EI_STATE_DISCONNECTED)
		return 0;

	return ei_proto_send_disconnect(ei);
}

static int
connection_send_add(struct ei *ei, struct ei_device *device)
{
	if (ei->state == EI_STATE_NEW ||
	    ei->state == EI_STATE_DISCONNECTED)
		return 0;

	return ei_proto_send_add(ei, device);
}

static int
connection_send_remove(struct ei *ei, struct ei_device *device)
{
	if (ei->state == EI_STATE_NEW ||
	    ei->state == EI_STATE_DISCONNECTED)
		return 0;

	return ei_proto_send_remove(ei, device);
}

static int
connection_send_rel(struct ei *ei, struct ei_device *device,
		    double x, double y)
{
	if (ei->state == EI_STATE_NEW ||
	    ei->state == EI_STATE_DISCONNECTED)
		return 0;

	return ei_proto_send_rel(ei, device, x, y);
}

static int
connection_send_button(struct ei *ei, struct ei_device *device,
		       uint32_t b, bool is_press)
{
	if (ei->state == EI_STATE_NEW ||
	    ei->state == EI_STATE_DISCONNECTED)
		return 0;

	return ei_proto_send_button(ei, device, b, is_press);
}

static int
connection_send_key(struct ei *ei, struct ei_device *device,
		    uint32_t k, bool is_press)
{
	if (ei->state == EI_STATE_NEW ||
	    ei->state == EI_STATE_DISCONNECTED)
		return 0;

	return ei_proto_send_key(ei, device, k, is_press);
}

static void
ei_disconnect(struct ei *ei)
{
	if (ei->state == EI_STATE_DISCONNECTED ||
	    ei->state == EI_STATE_DISCONNECTING)
		return;

	enum ei_state state = ei->state;

	/* We need the disconnecting state to be re-entrant
	   ei_device_remove() may call ei_disconnect() on a socket error */
	ei->state = EI_STATE_DISCONNECTING;

	struct ei_device *d, *tmp;
	list_for_each_safe(d, tmp, &ei->devices, link) {
		ei_device_remove(d);
	}

	if (state != EI_STATE_NEW) {
		connection_send_disconnect(ei);
		ei_queue_disconnect_event(ei);
	}
	ei->state = EI_STATE_DISCONNECTED;
	if (ei->source)
		source_remove(ei->source);
	ei->source = source_unref(ei->source);
}

int
ei_add_device(struct ei_device *device)
{
	struct ei *ei = ei_device_get_context(device);
	int rc = connection_send_add(ei, device);
	if (rc) {
		ei_disconnect(ei);
		return rc;
	}

	ei_device_ref(device);
	list_append(&ei->devices, &device->link);

	return 0;
}

int
ei_remove_device(struct ei_device *device)
{
	struct ei *ei = ei_device_get_context(device);
	int rc = connection_send_remove(ei, device);

	if (ei->state == EI_STATE_DISCONNECTING)
		ei_queue_removed_event(device);

	list_remove(&device->link);
	ei_device_unref(device);

	if (rc)
		ei_disconnect(ei);
	return rc;
}

static int
ei_added(struct ei *ei, uint32_t deviceid, uint32_t capabilities)
{
	struct ei_device *d;

	log_debug(ei, "Added device %d with caps %#x\n", deviceid, capabilities);

	list_for_each(d, &ei->devices, link) {
		if (d->id == deviceid) {
			ei_device_set_capabilities(d, capabilities);
			ei_device_added(d);
			ei_queue_added_event(d);
			return 0;
		}
	}

	/* Wrong device id or a device already removed by the client but we
	 * won't know which unless we keep some device ID table. Not worth
	 * it, so just silently ignore */
	return 0;
}

static int
ei_removed(struct ei *ei, uint32_t deviceid)
{
	struct ei_device *d;

	log_debug(ei, "Removed device %d\n", deviceid);

	list_for_each(d, &ei->devices, link) {
		if (d->id == deviceid) {
			ei_queue_removed_event(d);
			list_remove(&d->link);
			ei_device_unref(d);
			break;
		}
	}

	return 0;
}

static int
ei_resumed(struct ei *ei, uint32_t deviceid)
{
	struct ei_device *d;

	log_debug(ei, "Resumed device %d\n", deviceid);

	list_for_each(d, &ei->devices, link) {
		if (d->id == deviceid) {
			ei_device_resumed(d);
			ei_queue_resumed_event(d);
			break;
		}
	}

	return 0;
}

static int
ei_suspended(struct ei *ei, uint32_t deviceid)
{
	struct ei_device *d;

	log_debug(ei, "Suspended device %d\n", deviceid);

	list_for_each(d, &ei->devices, link) {
		if (d->id == deviceid) {
			ei_device_suspended(d);
			ei_queue_suspended_event(d);
			break;
		}
	}

	return 0;
}

int
ei_pointer_rel(struct ei_device *device, double x, double y)
{
	struct ei *ei = ei_device_get_context(device);
	int rc = connection_send_rel(ei, device, x, y);
	if (rc)
		ei_disconnect(ei);
	return rc;
}

int
ei_pointer_button(struct ei_device *device, uint32_t button, bool is_press)
{
	struct ei *ei = ei_device_get_context(device);
	int rc = connection_send_button(ei, device, button, is_press);
	if (rc)
		ei_disconnect(ei);
	return rc;
}

int
ei_keyboard_key(struct ei_device *device, uint32_t key, bool is_press)
{
	struct ei *ei = ei_device_get_context(device);
	int rc = connection_send_key(ei, device, key, is_press);
	if (rc)
		ei_disconnect(ei);
	return rc;
}

_public_ struct ei_event*
ei_get_event(struct ei *ei)
{
	if (list_empty(&ei->event_queue))
		return NULL;

	struct ei_event *e = list_first_entry(&ei->event_queue, e, link);
	list_remove(&e->link);

	return e;
}

_public_ struct ei_event*
ei_peek_event(struct ei *ei)
{
	if (list_empty(&ei->event_queue))
		return NULL;

	struct ei_event *e = list_first_entry(&ei->event_queue, e, link);
	return ei_event_ref(e);
}

static int
connection_new_handle_msg(struct ei *ei, struct message *msg)
{
	int rc = 0;

	switch (msg->type) {
	case MESSAGE_CONNECTED:
	case MESSAGE_DISCONNECTED:
	case MESSAGE_DEVICE_ADDED:
	case MESSAGE_DEVICE_REMOVED:
	case MESSAGE_DEVICE_RESUMED:
	case MESSAGE_DEVICE_SUSPENDED:
		rc = -EPROTO;
		break;
	}

	return rc;
}

static int
connection_connecting_handle_msg(struct ei *ei, struct message *msg)
{
	int rc = 0;

	switch (msg->type) {
	case MESSAGE_CONNECTED:
		ei->state = EI_STATE_CONNECTED;
		ei_queue_connect_event(ei);
		break;
	case MESSAGE_DISCONNECTED:
		rc = -ECANCELED;
		break;
	case MESSAGE_DEVICE_ADDED:
	case MESSAGE_DEVICE_REMOVED:
	case MESSAGE_DEVICE_RESUMED:
	case MESSAGE_DEVICE_SUSPENDED:
		rc = -EPROTO;
		break;
	}

	return rc;
}

static int
connection_connected_handle_msg(struct ei *ei, struct message *msg)
{
	int rc = 0;

	switch (msg->type) {
	case MESSAGE_CONNECTED:
		rc = -EPROTO;
		break;
	case MESSAGE_DISCONNECTED:
		rc = -ECANCELED;
		break;
	case MESSAGE_DEVICE_ADDED:
		rc = ei_added(ei, msg->added.deviceid, msg->added.capabilities);
		break;
	case MESSAGE_DEVICE_REMOVED:
		rc = ei_removed(ei, msg->removed.deviceid);
		break;
	case MESSAGE_DEVICE_RESUMED:
		rc = ei_resumed(ei, msg->resumed.deviceid);
		break;
	case MESSAGE_DEVICE_SUSPENDED:
		rc = ei_suspended(ei, msg->resumed.deviceid);
		break;
	}

	return rc;
}

static int
connection_message_callback(const char *msgdata, size_t len, void *userdata)
{
	struct ei *ei = userdata;
	size_t consumed;

	_cleanup_message_ struct message *msg =
		ei_proto_parse_message(msgdata, len, &consumed);
	if (!msg)
		return -EBADMSG;

	log_debug(ei, "Message type %d\n", msg->type);

	int rc = 0;
	switch (ei->state) {
		case EI_STATE_NEW:
			abort();
		case EI_STATE_BACKEND:
			rc = connection_new_handle_msg(ei, msg);
			break;
		case EI_STATE_CONNECTING:
			rc = connection_connecting_handle_msg(ei, msg);
			break;
		case EI_STATE_CONNECTED:
			rc = connection_connected_handle_msg(ei, msg);
			break;
		case EI_STATE_DISCONNECTING:
		case EI_STATE_DISCONNECTED:
			abort();
	}

	if (rc < 0)
		return rc;
	else
		return consumed;
}

static void
connection_dispatch(struct source *source, void *userdata)
{
	struct ei *ei = userdata;
	enum ei_state old_state = ei->state;

	int rc = brei_dispatch(source_get_fd(source), connection_message_callback, ei);
	if (rc < 0)
		ei_disconnect(ei);

	static const char *states[] = {
		"NEW",
		"BACKEND",
		"CONNECTING",
		"CONNECTED",
		"DISCONNECTED",
		"DISCONNECTING",
	};
	if (rc == -ECANCELED)
		log_info(ei, "Disconnected\n");
	else if (rc)
		log_warn(ei, "Connnection error: %s\n", strerror(-rc));

	log_debug(ei, "Connnection dispatch: %s -> %s\n",
		  states[old_state],
		  states[ei->state]);
}

int
ei_set_connection(struct ei *ei, int fd)
{
	struct source *source = source_new(fd, connection_dispatch, ei);
	int rc = sink_add_source(ei->sink, source);
	if (rc == 0) {
		ei->source = source_ref(source);
		ei->state = EI_STATE_BACKEND;
		rc = connection_send_connect(ei);
		if (rc != 0) {
			log_error(ei, "message failed to send: %s\n", strerror(-rc));
			ei_disconnect(ei);
		} else {
			ei->state = EI_STATE_CONNECTING;
		}
	}

	source_unref(source);

	return rc;
}

_public_ void
ei_configure_name(struct ei *ei, const char *name)
{
	if (ei->state != EI_STATE_NEW)
		return;

	if (strlen(name) > 1024)
		return;

	free(ei->name);
	ei->name = xstrdup(name);
}

#ifdef _enable_tests_
#include "util-munit.h"

MUNIT_TEST(test_init_unref)
{
	struct ei *ei = ei_new(NULL);

	munit_assert_int(ei->state, ==, EI_STATE_NEW);
	munit_assert(list_empty(&ei->event_queue));
	munit_assert(list_empty(&ei->devices));

	munit_assert_not_null(ei->sink);

	struct ei *refd = ei_ref(ei);
	munit_assert_ptr_equal(ei, refd);
	munit_assert_int(ei->object.refcount, ==, 2);

	struct ei *unrefd = ei_unref(ei);
	munit_assert_null(unrefd);

	unrefd = ei_unref(ei);
	munit_assert_null(unrefd);

	return MUNIT_OK;
}

MUNIT_TEST(test_configure_name)
{
	struct ei *ei = ei_new(NULL);

	ei_configure_name(ei, "foo");
	munit_assert_string_equal(ei->name, "foo");
	ei_configure_name(ei, "bar");
	munit_assert_string_equal(ei->name, "bar");

	/* ignore names that are too long */
	char buf[1200] = {0};
	memset(buf, 'a', sizeof(buf) - 1);
	ei_configure_name(ei, buf);
	munit_assert_string_equal(ei->name, "bar");

	/* ignore names in all other states */
	for (enum ei_state state = EI_STATE_NEW + 1;
	     state <= EI_STATE_DISCONNECTED;
	     state++) {
		ei->state = state;
		ei_configure_name(ei, "expect ignored");
		munit_assert_string_equal(ei->name, "bar");
	}

	ei_unref(ei);

	return MUNIT_OK;
}
#endif