/* SPDX-License-Identifier: MIT */
/*
 * 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-bits.h"
#include "util-io.h"
#include "util-macros.h"
#include "util-mem.h"
#include "util-sources.h"
#include "util-strings.h"
#include "util-structs.h"
#include "util-tristate.h"
#include "util-time.h"

#include "libeis-private.h"
#include "libeis-proto.h"
#include "brei-shared.h"
#include "eis-proto.h"

DEFINE_TRISTATE(started, finished, connected);

static void
eis_client_destroy(struct eis_client *client)
{
	eis_connection_unref(client->connection);
	free(client->name);
	source_remove(client->source);
	source_unref(client->source);
	list_remove(&client->link);
}

static
OBJECT_IMPLEMENT_CREATE(eis_client);
static
OBJECT_IMPLEMENT_PARENT(eis_client, eis);

_public_
OBJECT_IMPLEMENT_REF(eis_client);

_public_
OBJECT_IMPLEMENT_UNREF_CLEANUP(eis_client);

_public_
OBJECT_IMPLEMENT_GETTER(eis_client, name, const char*);
_public_
OBJECT_IMPLEMENT_SETTER(eis_client, user_data, void*);
_public_
OBJECT_IMPLEMENT_GETTER(eis_client, user_data, void*);

_public_ struct eis*
eis_client_get_context(struct eis_client *client)
{
	return eis_client_parent(client);
}

const struct brei_object *
eis_client_get_proto_object(struct eis_client *client)
{
	return &client->connection->proto_object;
}

uint32_t
eis_client_get_new_id(struct eis_client *client)
{
	static const int offset = 0xff000000;
	return offset | (client->next_object_id++ & ~offset);
}

void
eis_client_register_object(struct eis_client *client, struct brei_object *object)
{
	struct eis *eis = eis_client_get_context(client);
	log_debug(eis, "registering %s v%u object %#x", object->interface->name, object->version, object->id);
	list_append(&client->proto_objects, &object->link);
}

void
eis_client_unregister_object(struct eis_client *client, struct brei_object *object)
{
	struct eis *eis = eis_client_get_context(client);
	log_debug(eis, "deregistering %s v%u object %#x", object->interface->name, object->version, object->id);
	list_remove(&object->link);
}

struct eis_client *
eis_client_get_client(struct eis_client *client)
{
	return client;
}

_public_ bool
eis_client_is_sender(struct eis_client *client)
{
	return client->is_sender;
}

_public_ bool
eis_client_has_capability(struct eis_client *client,
			  enum eis_device_capability cap)
{
	switch (cap) {
	case EIS_DEVICE_CAP_POINTER:
	case EIS_DEVICE_CAP_POINTER_ABSOLUTE:
	case EIS_DEVICE_CAP_KEYBOARD:
	case EIS_DEVICE_CAP_TOUCH:
		return flag_is_set(client->restrictions.cap_allow_mask, cap);
	}

	/* Quietly ignore other capabilities, we don't want to future-proof this */
	if (cap == 0)
		log_bug_client(eis_client_get_context(client), "Check for invalid capability 0");
	return false;
}

static struct eis_device *
eis_client_find_device(struct eis_client *client, uint32_t deviceid)
{
	struct eis_seat *seat;

	list_for_each(seat, &client->seats, link) {
		struct eis_device *device;

		list_for_each(device, &seat->devices, link) {
			if (device->id == deviceid)
				return device;
		}
	}
	return NULL;
}

static struct eis_seat *
eis_client_find_seat(struct eis_client *client, uint32_t seatid)
{
	struct eis_seat *seat;

	list_for_each(seat, &client->seats, link) {
		if (seat->id == seatid)
			return seat;
	}

	return NULL;
}

int
eis_client_send_message(struct eis_client *client, uint32_t object_id,
			uint32_t opcode, const char *signature, size_t nargs, ...)
{
	struct eis *eis = eis_client_get_context(client);
	int fd = source_get_fd(client->source);

	log_debug(eis, "sending: %#x:%u signature '%s'", object_id, opcode, signature);

	va_list args;
	va_start(args, nargs);
	int rc = brei_send_message(fd, object_id, opcode, signature, nargs, args);
	va_end(args);
	return rc < 0 ? rc : 0;
}

static int
client_send_version(struct eis_client *client, uint32_t version)
{
	return eis_connection_event_version(client->connection, version);
}

static int
client_send_disconnect(struct eis_client *client)
{
	return eis_connection_event_disconnected(client->connection);
}

static int
client_send_connect(struct eis_client *client)
{
	return eis_connection_event_connected(client->connection);
}

static int
client_send_seat_added(struct eis_client *client, struct eis_seat *seat)
{
	return eis_connection_event_seat_added(client->connection, seat->id, seat->capabilities_mask, seat->name);
}

static int
client_send_seat_removed(struct eis_client *client, struct eis_seat *seat)
{
	return eis_connection_event_seat_removed(client->connection, seat->id);
}

static int
client_send_device_added(struct eis_client *client, struct eis_device *device)
{
	struct eis_seat *seat = eis_device_get_seat(device);
	int rc = eis_connection_event_device_added(client->connection, device->id, device->capabilities,
				        device->name, seat->id,
					device->type, device->width, device->height);

	if (rc >= 0 && device->keymap)
		rc = eis_connection_event_device_keymap(client->connection, device->id, device->keymap->type, device->keymap->size, device->keymap->fd);

	if (rc >= 0 && device->type == EIS_DEVICE_TYPE_VIRTUAL) {
		struct eis_region *r;
		list_for_each(r, &device->regions, link) {
			rc = eis_connection_event_device_region(client->connection, device->id, r->x, r->y, r->width, r->height, r->physical_scale);
		}
	}

	if (rc >= 0)
		rc = eis_connection_event_device_done(client->connection, device->id);
	return rc;
}

static int
client_send_device_removed(struct eis_client *client, struct eis_device *device)
{
	return eis_connection_event_device_removed(client->connection, device->id);
}

static int
client_send_device_paused(struct eis_client *client, struct eis_device *device)
{
	return eis_connection_event_device_paused(client->connection, device->id);
}

static int
client_send_device_resumed(struct eis_client *client, struct eis_device *device)
{
	return eis_connection_event_device_resumed(client->connection, device->id);
}

static int
client_send_keyboard_modifiers(struct eis_client *client, struct eis_device *device,
			       const struct eis_xkb_modifiers *mods)
{
	return eis_connection_event_keyboard_modifiers(client->connection, device->id,
					    mods->depressed, mods->locked,
					    mods->latched, mods->group);
}

_public_ void
eis_client_connect(struct eis_client *client)
{
	switch(client->state) {
	case EIS_CLIENT_STATE_DISCONNECTED:
		return;
	case EIS_CLIENT_STATE_CONNECTING:
		break;
	default:
		log_bug_client(eis_client_get_context(client),
			       "%s: client already connected", __func__);
		return;
	}

	int rc = client_send_connect(client);
	if (rc) {
		log_debug(eis_client_get_context(client), "Message failed to send: %s", strerror(-rc));
		eis_client_disconnect(client);
	} else {
		client->state = EIS_CLIENT_STATE_CONNECTED;
	}
}

_public_ void
eis_client_disconnect(struct eis_client *client)
{
	switch(client->state) {
	case EIS_CLIENT_STATE_DISCONNECTED:
		/* Client already disconnected? don't bother sending an
		 * event */
		return;
	case EIS_CLIENT_STATE_CONNECTING:
	case EIS_CLIENT_STATE_CONNECTED:
		{
			struct eis_seat *s;
			list_for_each_safe(s, &client->seats, link) {
				eis_seat_drop(s);
			}
		}
		eis_queue_disconnect_event(client);
		_fallthrough_;
	case EIS_CLIENT_STATE_NEW:
		client_send_disconnect(client);
		client->state = EIS_CLIENT_STATE_DISCONNECTED;
		source_remove(client->source);
		break;
	}

	eis_client_unref(client);
}

static int
client_msg_close_device(struct eis_connection *connection, uint32_t deviceid)
{
	struct eis_client *client = eis_connection_get_client(connection);
	struct eis_device *device = eis_client_find_device(client, deviceid);

	if (device)
		eis_device_closed_by_client(device);

	return 0;
}

static int
client_msg_bind_seat(struct eis_connection *connection, uint32_t seatid, uint32_t caps)
{
	struct eis_client *client = eis_connection_get_client(connection);
	struct eis_seat *seat = eis_client_find_seat(client, seatid);

	if (seat)
		eis_seat_bind(seat, caps);

	return seat ? 0 : -EINVAL;
}

#define DISCONNECT_IF_RECEIVER_CONTEXT(client_) do { \
	if (!(client_)->is_sender) { \
		struct eis *_ctx = eis_client_get_context(client_); \
		log_bug_client(_ctx, "Invalid event from receiver ei context. Disconnecting client"); \
		return -EINVAL; \
	} \
} while(0)

static int
client_msg_start_emulating(struct eis_connection *connection, uint32_t deviceid, uint32_t sequence)
{
	struct eis_client *client = eis_connection_get_client(connection);

	DISCONNECT_IF_RECEIVER_CONTEXT(client);

	struct eis_device *device = eis_client_find_device(client, deviceid);

	if (device)
		eis_device_event_start_emulating(device, sequence);

	return 0;
}

static int
client_msg_stop_emulating(struct eis_connection *connection, uint32_t deviceid)
{
	struct eis_client *client = eis_connection_get_client(connection);

	DISCONNECT_IF_RECEIVER_CONTEXT(client);

	struct eis_device *device = eis_client_find_device(client, deviceid);

	if (device)
		eis_device_event_stop_emulating(device);

	return 0;
}

static int
client_msg_frame(struct eis_connection *connection, uint32_t deviceid, uint32_t time, uint32_t micros)
{
	struct eis_client *client = eis_connection_get_client(connection);

	DISCONNECT_IF_RECEIVER_CONTEXT(client);

	struct eis_device *device = eis_client_find_device(client, deviceid);

	if (device)
		return eis_device_event_frame(device, ms2us(time) + micros);

	return 0;
}

static int
client_msg_pointer_rel(struct eis_connection *connection, uint32_t deviceid,
		       float x, float y)
{
	struct eis_client *client = eis_connection_get_client(connection);

	DISCONNECT_IF_RECEIVER_CONTEXT(client);

	struct eis_device *device = eis_client_find_device(client, deviceid);

	if (device)
		return eis_device_event_pointer_rel(device, x, y);

	return -EINVAL;
}

static int
client_msg_pointer_abs(struct eis_connection *connection, uint32_t deviceid,
		       float x, float y)
{
	struct eis_client *client = eis_connection_get_client(connection);

	DISCONNECT_IF_RECEIVER_CONTEXT(client);

	struct eis_device *device = eis_client_find_device(client, deviceid);

	if (device)
		return eis_device_event_pointer_abs(device, x, y);

	return -EINVAL;
}

static int
client_msg_pointer_button(struct eis_connection *connection, uint32_t deviceid,
			  uint32_t button, uint32_t state)
{
	struct eis_client *client = eis_connection_get_client(connection);

	DISCONNECT_IF_RECEIVER_CONTEXT(client);

	struct eis_device *device = eis_client_find_device(client, deviceid);

	if (device)
		return eis_device_event_pointer_button(device, button, !!state);

	return -EINVAL;
}

static int
client_msg_pointer_scroll(struct eis_connection *connection, uint32_t deviceid,
			  float x, float y)
{
	struct eis_client *client = eis_connection_get_client(connection);

	DISCONNECT_IF_RECEIVER_CONTEXT(client);

	struct eis_device *device = eis_client_find_device(client, deviceid);

	if (device)
		return eis_device_event_pointer_scroll(device, x, y);

	return -EINVAL;
}

static int
client_msg_pointer_scroll_discrete(struct eis_connection *connection, uint32_t deviceid,
				   int32_t x, int32_t y)
{
	struct eis_client *client = eis_connection_get_client(connection);

	DISCONNECT_IF_RECEIVER_CONTEXT(client);

	struct eis_device *device = eis_client_find_device(client, deviceid);

	if (device)
		return eis_device_event_pointer_scroll_discrete(device, x, y);

	return -EINVAL;
}

static int
client_msg_pointer_scroll_stop(struct eis_connection *connection, uint32_t deviceid,
			       uint32_t x, uint32_t y, uint32_t is_cancel)
{
	struct eis_client *client = eis_connection_get_client(connection);

	DISCONNECT_IF_RECEIVER_CONTEXT(client);

	struct eis_device *device = eis_client_find_device(client, deviceid);

	if (device) {
		if (is_cancel)
			return eis_device_event_pointer_scroll_cancel(device, !!x, !!y);
		else
			return eis_device_event_pointer_scroll_stop(device, !!x, !!y);
	}

	return -EINVAL;
}

static int
client_msg_keyboard_key(struct eis_connection *connection, uint32_t deviceid,
			uint32_t key, uint32_t state)
{
	struct eis_client *client = eis_connection_get_client(connection);

	DISCONNECT_IF_RECEIVER_CONTEXT(client);

	struct eis_device *device = eis_client_find_device(client, deviceid);

	if (device)
		return eis_device_event_keyboard_key(device, key, !!state);

	return -EINVAL;
}

static int
client_msg_touch_down(struct eis_connection *connection, uint32_t deviceid,
		      uint32_t touchid, float x, float y)
{
	struct eis_client *client = eis_connection_get_client(connection);

	DISCONNECT_IF_RECEIVER_CONTEXT(client);

	struct eis_device *device = eis_client_find_device(client, deviceid);

	if (device)
		return eis_device_event_touch_down(device, touchid, x, y);

	return -EINVAL;
}

static int
client_msg_touch_motion(struct eis_connection *connection, uint32_t deviceid,
			uint32_t touchid, float x, float y)
{
	struct eis_client *client = eis_connection_get_client(connection);

	DISCONNECT_IF_RECEIVER_CONTEXT(client);

	struct eis_device *device = eis_client_find_device(client, deviceid);

	if (device)
		return eis_device_event_touch_motion(device, touchid, x, y);

	return -EINVAL;
}

static int
client_msg_touch_up(struct eis_connection *connection, uint32_t deviceid, uint32_t touchid)
{
	struct eis_client *client = eis_connection_get_client(connection);

	DISCONNECT_IF_RECEIVER_CONTEXT(client);

	struct eis_device *device = eis_client_find_device(client, deviceid);

	if (device)
		return eis_device_event_touch_up(device, touchid);

	return -EINVAL;
}

static int
client_msg_connect(struct eis_connection *connection, uint32_t version,
		   const char *name, uint32_t is_sender)
{
	struct eis_client *client = eis_connection_get_client(connection);

	if (client->version > EIS_PROTOCOL_VERSION)
		return -EPROTO;

	client->version = version;

	if (client->name == NULL)
		client->name = xstrdup(name);

	client->is_sender = !!is_sender;

	return 0;
}

static int
client_msg_connect_done(struct eis_connection *connection)
{
	struct eis_client *client = eis_connection_get_client(connection);

	eis_queue_connect_event(client);
	client->state = EIS_CLIENT_STATE_CONNECTING;

	return 0;
}

static int
client_msg_disconnect(struct eis_connection *connection)
{
	return -ECANCELED;
}

static int
client_msg_get_version(struct eis_connection *connection)
{
	struct eis_client *client = eis_connection_get_client(connection);
	return client_send_version(client, EI_PROTOCOL_VERSION);
}

static const struct eis_connection_interface intf_state_new = {
	.connect = client_msg_connect,
	.connect_done = client_msg_connect_done,
	.disconnect = client_msg_disconnect,
	.get_version = client_msg_get_version,
};

/* Client is waiting for us, shouldn't send anything except disconnect */
static const struct eis_connection_interface intf_state_connecting = {
	.disconnect = client_msg_disconnect,
	.get_version = client_msg_get_version,
};

static const struct eis_connection_interface intf_state_connected = {
	.disconnect = client_msg_disconnect,
	.bind_seat = client_msg_bind_seat,
	.close_device = client_msg_close_device,
	.get_version = client_msg_get_version,

	/* events */
	.start_emulating = client_msg_start_emulating,
	.stop_emulating = client_msg_stop_emulating,
	.pointer_relative = client_msg_pointer_rel,
	.pointer_absolute = client_msg_pointer_abs,
	.pointer_button = client_msg_pointer_button,
	.pointer_scroll = client_msg_pointer_scroll,
	.pointer_scroll_stop = client_msg_pointer_scroll_stop,
	.pointer_scroll_discrete = client_msg_pointer_scroll_discrete,
	.keyboard_key = client_msg_keyboard_key,
	.touch_down = client_msg_touch_down,
	.touch_motion = client_msg_touch_motion,
	.touch_up = client_msg_touch_up,
	.frame = client_msg_frame,
};

static const struct eis_connection_interface *interfaces[] = {
	[EIS_CLIENT_STATE_NEW] = &intf_state_new,
	[EIS_CLIENT_STATE_CONNECTING] = &intf_state_connecting,
	[EIS_CLIENT_STATE_CONNECTED] = &intf_state_connected,
	[EIS_CLIENT_STATE_DISCONNECTED] = NULL,
};

const struct eis_connection_interface *
eis_client_get_interface(struct eis_client *client)
{
	assert(client->state < ARRAY_LENGTH(interfaces));
	return interfaces[client->state];
}

static int
lookup_object(uint32_t object_id, struct brei_object **object, void *userdata)
{
	struct eis_client *client = userdata;

	struct brei_object *obj;
	list_for_each(obj, &client->proto_objects, link) {
		if (obj->id == object_id) {
			*object = obj;
			return 0;
		}
	}

	return -ENOENT;
}

static void
client_dispatch(struct source *source, void *userdata)
{
	_unref_(eis_client) *client = eis_client_ref(userdata);
	enum eis_client_state old_state = client->state;

	int rc = brei_dispatch(source_get_fd(source), lookup_object, client);
	if (rc < 0) {
		brei_drain_fd(source_get_fd(source));
		eis_client_disconnect(client);
	}

	static const char *client_states[] = {
		"NEW",
		"CONFIGURING",
		"CONFIGURED",
		"CONNECTING",
		"CONNECTED",
		"DISCONNECTED",
	};
	if (rc == -ECANCELED)
		log_info(eis_client_get_context(client), "Disconnected");
	else if (rc)
		log_warn(eis_client_get_context(client), "Client error: %s",
			 strerror(-rc));
	if (old_state != client->state) {
		assert(old_state < ARRAY_LENGTH(client_states));
		assert(client->state < ARRAY_LENGTH(client_states));
		log_debug(eis_client_get_context(client), "Client dispatch: %s -> %s",
			  client_states[old_state],
			  client_states[client->state]);
	}

}

struct eis_client *
eis_client_new(struct eis *eis, int fd)
{
	static uint32_t client_id;
	struct eis_client *client = eis_client_create(&eis->object);

	client->is_sender = true;
	client->id = ++client_id;
	list_init(&client->seats);
	list_init(&client->seats_pending);
	list_init(&client->proto_objects);

	client->connection = eis_connection_new(client);

	struct source *s = source_new(fd, client_dispatch, client);
	int rc = sink_add_source(eis->sink, s);

	if (rc != 0) {
		source_unref(s);
		return NULL;
	}

	client->source = source_ref(s);
	client->state = EIS_CLIENT_STATE_NEW;
	client->restrictions.cap_allow_mask =
		bit(EIS_DEVICE_CAP_KEYBOARD) |
		bit(EIS_DEVICE_CAP_POINTER) |
		bit(EIS_DEVICE_CAP_POINTER_ABSOLUTE) |
		bit(EIS_DEVICE_CAP_TOUCH);

	eis_add_client(eis, eis_client_ref(client));

	source_unref(s);

	/* Immediately send our version so the client doesn't need a roundtrip */
	client_send_version(client, EI_PROTOCOL_VERSION);

	return client;
}

void
eis_client_add_seat(struct eis_client *client, struct eis_seat *seat)
{
	/* remove from the pending list first */
	list_remove(&seat->link);
	/* We own this seat now */
	eis_seat_ref(seat);
	list_append(&client->seats, &seat->link);
	client_send_seat_added(client, seat);
}

void
eis_client_remove_seat(struct eis_client *client, struct eis_seat *seat)
{
	client_send_seat_removed(client, seat);
	seat->state = EIS_SEAT_STATE_REMOVED;
}

void
eis_client_add_device(struct eis_client *client, struct eis_device *device)
{
	client_send_device_added(client, device);
}

void
eis_client_remove_device(struct eis_client *client, struct eis_device *device)
{
	client_send_device_removed(client, device);
}

void
eis_client_pause_device(struct eis_client *client, struct eis_device *device)
{
	client_send_device_paused(client, device);
}

void
eis_client_resume_device(struct eis_client *client, struct eis_device *device)
{
	client_send_device_resumed(client, device);
}

void
eis_client_keyboard_modifiers(struct eis_client *client, struct eis_device *device,
			      uint32_t depressed, uint32_t latched, uint32_t locked,
			      uint32_t group)
{
	struct eis_xkb_modifiers mods = {
		.depressed = depressed,
		.locked = locked,
		.latched = latched,
		.group = group,
	};
	client_send_keyboard_modifiers(client, device, &mods);
}