/*
 * 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 "libeis-private.h"
#include "libeis-proto.h"
#include "brei-shared.h"

static void
eis_client_destroy(struct eis_client *client)
{
	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(eis_client);
#define _cleanup_eis_client_ _cleanup_(eis_client_cleanup)

_public_
OBJECT_IMPLEMENT_GETTER(eis_client, name, const char*);

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

static int
client_send_disconnect(struct eis_client *client)
{
	return eis_proto_send_disconnect(client);
}

static int
client_send_connect(struct eis_client *client)
{
	return eis_proto_send_connect(client);
}

static int
client_send_device_added(struct eis_client *client, struct eis_device *device)
{
	return eis_proto_send_device_added(client, device);
}

static int
client_send_device_removed(struct eis_client *client, struct eis_device *device)
{
	return eis_proto_send_device_removed(client, device);
}

static int
client_send_device_suspended(struct eis_client *client, struct eis_device *device)
{
	return eis_proto_send_device_suspended(client, device);
}

static int
client_send_device_resumed(struct eis_client *client, struct eis_device *device)
{
	return eis_proto_send_device_resumed(client, device);
}

_public_ void
eis_client_connect(struct eis_client *client)
{
	switch(client->state) {
	case EIS_CLIENT_STATE_CONNECTING:
		break;
	default:
		return;
	}

	int rc = client_send_connect(client);
	if (rc) {
		log_debug(eis_client_get_context(client), "Message failed to send: %s\n", 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_device *d, *tmp;
			list_for_each_safe(d, tmp, &client->devices, link)
				eis_device_disconnect(d);
		}
		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_new_device(struct eis_client *client,
		  uint32_t id, const char *name, uint32_t capabilities,
		  const struct dimensions *dim_pointer,
		  const struct dimensions *dim_touch,
		  enum eis_keymap_type keymap_type,
		  int keymap_fd, size_t keymap_sz)
{
	/* Check for duplicate IDs */
	struct eis_device *d;
	list_for_each(d, &client->devices, link) {
		if (d->id == id)
			return -EINVAL;
	}

	if (capabilities == 0 ||
	    capabilities & ~(bit(EIS_DEVICE_CAP_POINTER) |
			     bit(EIS_DEVICE_CAP_POINTER_ABSOLUTE) |
			     bit(EIS_DEVICE_CAP_KEYBOARD) |
			     bit(EIS_DEVICE_CAP_TOUCH)))
		return -EINVAL;

	struct eis_device *device = eis_device_new(client, id, name, capabilities);
	list_append(&client->devices, &device->link);

	if (flag_is_set(capabilities, EIS_DEVICE_CAP_POINTER_ABSOLUTE))
		eis_device_set_pointer_range(device, dim_pointer->width,
					     dim_pointer->height);

	if (flag_is_set(capabilities, EIS_DEVICE_CAP_TOUCH))
		eis_device_set_touch_range(device, dim_touch->width,
					   dim_touch->height);

	eis_device_set_client_keymap(device, keymap_type, keymap_fd, keymap_sz);

	log_debug(eis_client_parent(client),
		  "New device %d '%s' caps: %s%s%s%s\n",
		  id, name,
		  eis_device_has_capability(device, EIS_DEVICE_CAP_POINTER) ? "p" : "",
		  eis_device_has_capability(device, EIS_DEVICE_CAP_POINTER_ABSOLUTE) ? "a" : "",
		  eis_device_has_capability(device, EIS_DEVICE_CAP_KEYBOARD) ? "k" : "",
		  eis_device_has_capability(device, EIS_DEVICE_CAP_TOUCH) ? "t" : "");

	eis_queue_added_event(device);

	return 0;
}

static int
client_remove_device(struct eis_client *client, uint32_t deviceid)
{
	struct eis_device *device;

	list_for_each(device, &client->devices, link) {
		if (device->id == deviceid) {
			eis_queue_removed_event(device);
			break;
		}
	}
	return 0;
}

static int
client_pointer_rel(struct eis_client *client, uint32_t deviceid,
		   double x, double y)
{
	struct eis_device *device;

	list_for_each(device, &client->devices, link) {
		if (device->id == deviceid) {
			return eis_device_pointer_rel(device, x, y);
		}
	}
	return -EINVAL;
}

static int
client_pointer_button(struct eis_client *client, uint32_t deviceid,
		      uint32_t button, bool state)
{
	struct eis_device *device;

	list_for_each(device, &client->devices, link) {
		if (device->id == deviceid) {
			return eis_device_pointer_button(device, button, state);
		}
	}
	return -EINVAL;
}

static int
client_keyboard_key(struct eis_client *client, uint32_t deviceid,
		    uint32_t key, bool state)
{
	struct eis_device *device;

	list_for_each(device, &client->devices, link) {
		if (device->id == deviceid) {
			return eis_device_keyboard_key(device, key, state);
		}
	}
	return -EINVAL;
}

static int
client_configure_name(struct eis_client *client, const char *name)
{
	/* We silently ignore wrong configure messages */
	if (client->state != EIS_CLIENT_STATE_NEW || client->name)
		return 0;

	client->name = xstrdup(name);

	return 0;
}

static int
client_configure_caps(struct eis_client *client, bool policy_is_allow,
		      uint32_t allowed_caps, uint32_t denied_caps)
{
	if (policy_is_allow) {
		/* We can only manage allow masks while we're in
		 * default-allow policy.
		 * first call to set allow masks is taken as-is, from then onwards
		 *  we can only restrict */
		if (client->restrictions.cap_allow_mask == ~0U)
			client->restrictions.cap_allow_mask = allowed_caps;
		else
			client->restrictions.cap_allow_mask &= allowed_caps;
	} else {
		client->restrictions.cap_policy = CLIENT_CAP_POLICY_DENY;
	}

	client->restrictions.cap_deny_mask |= denied_caps;

	/* FIXME: if something is disallowed now, we should disconnect
	 * accordingly.
	 */

	return 0;
}

static int
client_new_handle_msg(struct eis_client *client, struct message *msg)
{
	int rc = 0;

	switch (msg->type) {
	case MESSAGE_CONNECT:
		eis_queue_connect_event(client);
		if (client->name == NULL)
			client->name = steal(&msg->connect.name);
		client->state = EIS_CLIENT_STATE_CONNECTING;
		break;
	case MESSAGE_DISCONNECT:
		rc = -ECANCELED;
		break;
	case MESSAGE_ADD_DEVICE:
	case MESSAGE_REMOVE_DEVICE:
	case MESSAGE_POINTER_REL:
	case MESSAGE_POINTER_BUTTON:
	case MESSAGE_KEYBOARD_KEY:
		rc = -EPROTO;
		break;
	case MESSAGE_CONFIGURE_NAME:
		rc = client_configure_name(client, msg->configure_name.name);
		break;
	case MESSAGE_CONFIGURE_CAPABILITIES:
		rc = client_configure_caps(client, msg->configure_caps.policy_is_allow,
					   msg->configure_caps.caps_allow,
					   msg->configure_caps.caps_deny);
		break;
	}

	return rc;
}

static int
client_connecting_handle_msg(struct eis_client *client, const struct message *msg)
{
	int rc = 0;

	switch (msg->type) {
	case MESSAGE_CONNECT:
		rc = -EPROTO;
		break;
	case MESSAGE_DISCONNECT:
		rc = -ECANCELED;
		break;
	case MESSAGE_ADD_DEVICE:
	case MESSAGE_REMOVE_DEVICE:
	case MESSAGE_POINTER_REL:
	case MESSAGE_POINTER_BUTTON:
	case MESSAGE_KEYBOARD_KEY:
		rc = -EPROTO;
		break;
	case MESSAGE_CONFIGURE_NAME:
		rc = client_configure_name(client, msg->configure_name.name);
		break;
	case MESSAGE_CONFIGURE_CAPABILITIES:
		rc = client_configure_caps(client, msg->configure_caps.policy_is_allow,
					   msg->configure_caps.caps_allow,
					   msg->configure_caps.caps_deny);
		break;
	}

	return rc;
}

static int
client_connected_handle_msg(struct eis_client *client,
			    const struct message *msg)
{
	int rc = 0;

	switch (msg->type) {
	case MESSAGE_CONNECT:
		rc = -EPROTO;
		break;
	case MESSAGE_DISCONNECT:
		rc = -ECANCELED;
		break;
	case MESSAGE_ADD_DEVICE:
		rc = client_new_device(client, msg->add_device.deviceid,
				       msg->add_device.name,
				       msg->add_device.capabilities,
				       &msg->add_device.dim_pointer,
				       &msg->add_device.dim_touch,
				       msg->add_device.keymap_type,
				       msg->add_device.keymap_fd,
				       msg->add_device.keymap_size);
		break;
	case MESSAGE_REMOVE_DEVICE:
		rc = client_remove_device(client, msg->remove_device.deviceid);
		break;
	case MESSAGE_POINTER_REL:
		rc = client_pointer_rel(client, msg->pointer_rel.deviceid,
					msg->pointer_rel.x, msg->pointer_rel.y);
		break;
	case MESSAGE_POINTER_BUTTON:
		rc = client_pointer_button(client, msg->pointer_button.deviceid,
					   msg->pointer_button.button,
					   msg->pointer_button.state);
		break;
	case MESSAGE_KEYBOARD_KEY:
		rc = client_keyboard_key(client, msg->keyboard_key.deviceid,
					 msg->keyboard_key.key,
					 msg->keyboard_key.state);
		break;
	case MESSAGE_CONFIGURE_NAME:
		rc = client_configure_name(client, msg->configure_name.name);
		break;
	case MESSAGE_CONFIGURE_CAPABILITIES:
		rc = client_configure_caps(client, msg->configure_caps.policy_is_allow,
					   msg->configure_caps.caps_allow,
					   msg->configure_caps.caps_deny);
		break;
	}
	return rc;
}

static int
client_message_callback(struct brei_message *bmsg, void *userdata)
{
	struct eis_client *client = userdata;
	size_t consumed;

	_cleanup_message_ struct message *msg = eis_proto_parse_message(bmsg, &consumed);
	if (!msg)
		return -EBADMSG;

	int rc = 0;
	switch (client->state) {
		case EIS_CLIENT_STATE_NEW:
			rc = client_new_handle_msg(client, msg);
			break;
		case EIS_CLIENT_STATE_CONNECTING:
			/* Client is waiting for us, shouldn't send anything
			 * but disconnect */
			rc = client_connecting_handle_msg(client, msg);
			break;
		case EIS_CLIENT_STATE_CONNECTED:
			rc = client_connected_handle_msg(client, msg);
			break;
		case EIS_CLIENT_STATE_DISCONNECTED:
			abort();
	}

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

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

	int rc = brei_dispatch(source_get_fd(source), client_message_callback, client);
	if (rc < 0)
		eis_client_disconnect(client);

	static const char *client_states[] = {
		"NEW",
		"CONNECTING",
		"CONNECTED",
		"DISCONNECTED",
	};
	if (rc == -ECANCELED)
		log_info(eis_client_parent(client), "Disconnected\n");
	else if (rc)
		log_warn(eis_client_parent(client), "Client error: %s\n",
			 strerror(-rc));
	if (old_state != client->state) {
		log_debug(eis_client_parent(client), "Client dispatch: %s -> %s\n",
			  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->id = ++client_id;
	list_init(&client->devices);

	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_policy = CLIENT_CAP_POLICY_ALLOW;
	client->restrictions.cap_allow_mask = ~0U;
	client->restrictions.cap_deny_mask = 0;

	eis_add_client(eis, eis_client_ref(client));

	source_unref(s);

	return client;
}

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

void
eis_client_disconnect_device(struct eis_client *client, struct eis_device *device)
{
	client_send_device_removed(client, device);
	eis_queue_removed_event(device);
	list_remove(&device->link);
	eis_device_unref(device);
}

void
eis_client_suspend_device(struct eis_client *client, struct eis_device *device)
{
	client_send_device_suspended(client, device);
}

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