Merge branch 'isse/very-cool-commands' into 'master'

Target any entity with commands, and a few new commands.

See merge request veloren/veloren!4192

CHANGELOG.md

@@ -34,6 +34,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Crafting recipe for Cloverleaf glider.
 - Burning Potion that applies the Burning effect to the user
 - Precision
+- A few new commands, `/tether`, `/destroy_tethers`, `/mount` and `/dismount`.
+- A way to target non-player entities with commands. With rtsim_id: `rtsim@<id>`, with uid: `uid@<id>`.
+- Shorthand in voxygen for specific entities in commands, some examples `@target`, `@mount`, `@viewpoint`.
 
 ### Changed
 

assets/voxygen/i18n/en/command.ftl

@@ -92,3 +92,7 @@ command-kit-inventory-unavailable = Could not get inventory
 command-inventory-cant-fit-item = Can't fit item to inventory
 # Emitted by /disconnect_all when you dont exist (?)
 command-you-dont-exist = You do not exist, so you cannot use this command
+command-destroyed-tethers = All tethers destroyed! You are now free
+command-destroyed-no-tethers = You're not connected to any tethers
+command-dismounted = Dismounted
+command-no-dismount = You're not riding or being ridden

common/src/cmd.rs

@@ -263,6 +263,39 @@ lazy_static! {
     };
 }
 
+pub enum EntityTarget {
+    Player(String),
+    RtsimNpc(u64),
+    Uid(crate::uid::Uid),
+}
+
+impl FromStr for EntityTarget {
+    type Err = String;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        // NOTE: `@` is an invalid character in usernames, so we can use it here.
+        if let Some((spec, data)) = s.split_once('@') {
+            match spec {
+                "rtsim" => Ok(EntityTarget::RtsimNpc(u64::from_str(data).map_err(
+                    |_| format!("Expected a valid number after 'rtsim@' but found {data}."),
+                )?)),
+                "uid" => Ok(EntityTarget::Uid(
+                    u64::from_str(data)
+                        .map_err(|_| {
+                            format!("Expected a valid number after 'uid@' but found {data}.")
+                        })?
+                        .into(),
+                )),
+                _ => Err(format!(
+                    "Expected either 'rtsim' or 'uid' before '@' but found '{spec}'"
+                )),
+            }
+        } else {
+            Ok(EntityTarget::Player(s.to_string()))
+        }
+    }
+}
+
 // Please keep this sorted alphabetically :-)
 #[derive(Copy, Clone, strum::EnumIter)]
 pub enum ServerChatCommand {
@@ -283,7 +316,9 @@ pub enum ServerChatCommand {
     DebugColumn,
     DebugWays,
     DeleteLocation,
+    DestroyTethers,
     DisconnectAllPlayers,
+    Dismount,
     DropAll,
     Dummy,
     Explosion,
@@ -312,6 +347,7 @@ pub enum ServerChatCommand {
     MakeSprite,
     MakeVolume,
     Motd,
+    Mount,
     Object,
     PermitBuild,
     Players,
@@ -340,6 +376,7 @@ pub enum ServerChatCommand {
     Spawn,
     Sudo,
     Tell,
+    Tether,
     Time,
     TimeScale,
     Tp,
@@ -739,8 +776,8 @@ impl ServerChatCommand {
                 Some(Admin),
             ),
             ServerChatCommand::Sudo => cmd(
-                vec![PlayerName(Required), SubCommand],
-                "Run command as if you were another player",
+                vec![EntityTarget(Required), SubCommand],
+                "Run command as if you were another entity",
                 Some(Moderator),
             ),
             ServerChatCommand::Tell => cmd(
@@ -760,10 +797,10 @@ impl ServerChatCommand {
             ),
             ServerChatCommand::Tp => cmd(
                 vec![
-                    PlayerName(Optional),
+                    EntityTarget(Optional),
                     Boolean("Dismount from ship", "true".to_string(), Optional),
                 ],
-                "Teleport to another player",
+                "Teleport to another entity",
                 Some(Moderator),
             ),
             ServerChatCommand::RtsimTp => cmd(
@@ -862,6 +899,25 @@ impl ServerChatCommand {
             ServerChatCommand::RepairEquipment => {
                 cmd(vec![], "Repairs all equipped items", Some(Admin))
             },
+            ServerChatCommand::Tether => cmd(
+                vec![
+                    EntityTarget(Required),
+                    Boolean("automatic length", "true".to_string(), Optional),
+                ],
+                "Tether another entity to yourself",
+                Some(Admin),
+            ),
+            ServerChatCommand::DestroyTethers => {
+                cmd(vec![], "Destroy all tethers connected to you", Some(Admin))
+            },
+            ServerChatCommand::Mount => {
+                cmd(vec![EntityTarget(Required)], "Mount an entity", Some(Admin))
+            },
+            ServerChatCommand::Dismount => cmd(
+                vec![EntityTarget(Required)],
+                "Dismount if you are riding, or dismount anything riding you",
+                Some(Admin),
+            ),
         }
     }
 
@@ -952,6 +1008,10 @@ impl ServerChatCommand {
             ServerChatCommand::Lightning => "lightning",
             ServerChatCommand::Scale => "scale",
             ServerChatCommand::RepairEquipment => "repair_equipment",
+            ServerChatCommand::Tether => "tether",
+            ServerChatCommand::DestroyTethers => "destroy_tethers",
+            ServerChatCommand::Mount => "mount",
+            ServerChatCommand::Dismount => "dismount",
         }
     }
 
@@ -1001,6 +1061,7 @@ impl ServerChatCommand {
             .iter()
             .map(|arg| match arg {
                 ArgumentSpec::PlayerName(_) => "{}",
+                ArgumentSpec::EntityTarget(_) => "{}",
                 ArgumentSpec::SiteName(_) => "{/.*/}",
                 ArgumentSpec::Float(_, _, _) => "{}",
                 ArgumentSpec::Integer(_, _, _) => "{d}",
@@ -1037,7 +1098,7 @@ impl FromStr for ServerChatCommand {
     }
 }
 
-#[derive(Eq, PartialEq, Debug)]
+#[derive(Eq, PartialEq, Debug, Clone, Copy)]
 pub enum Requirement {
     Required,
     Optional,
@@ -1047,6 +1108,8 @@ pub enum Requirement {
 pub enum ArgumentSpec {
     /// The argument refers to a player by alias
     PlayerName(Requirement),
+    /// The arguments refers to an entity in some way.
+    EntityTarget(Requirement),
     // The argument refers to a site, by name.
     SiteName(Requirement),
     /// The argument is a float. The associated values are
@@ -1090,6 +1153,13 @@ impl ArgumentSpec {
                     "[player]".to_string()
                 }
             },
+            ArgumentSpec::EntityTarget(req) => {
+                if &Requirement::Required == req {
+                    "<entity>".to_string()
+                } else {
+                    "[entity]".to_string()
+                }
+            },
             ArgumentSpec::SiteName(req) => {
                 if &Requirement::Required == req {
                     "<site>".to_string()
@@ -1149,6 +1219,22 @@ impl ArgumentSpec {
             },
         }
     }
+
+    pub fn requirement(&self) -> Requirement {
+        match self {
+            ArgumentSpec::PlayerName(r)
+            | ArgumentSpec::EntityTarget(r)
+            | ArgumentSpec::SiteName(r)
+            | ArgumentSpec::Float(_, _, r)
+            | ArgumentSpec::Integer(_, _, r)
+            | ArgumentSpec::Any(_, r)
+            | ArgumentSpec::Command(r)
+            | ArgumentSpec::Message(r)
+            | ArgumentSpec::Enum(_, _, r)
+            | ArgumentSpec::Boolean(_, _, r) => *r,
+            ArgumentSpec::SubCommand => Requirement::Required,
+        }
+    }
 }
 
 /// Parse a series of command arguments into values, including collecting all

common/src/mounting.rs

@@ -279,6 +279,14 @@ pub struct VolumeRiders {
     riders: HashSet<Vec3<i32>>,
 }
 
+impl VolumeRiders {
+    pub fn clear(&mut self) -> bool {
+        let res = !self.riders.is_empty();
+        self.riders.clear();
+        res
+    }
+}
+
 impl Component for VolumeRiders {
     type Storage = DenseVecStorage<Self>;
 }

server/src/cmd.rs

@@ -21,7 +21,7 @@ use common::{
     assets,
     calendar::Calendar,
     cmd::{
-        AreaKind, KitSpec, ServerChatCommand, BUFF_PACK, BUFF_PARSER, ITEM_SPECS,
+        AreaKind, EntityTarget, KitSpec, ServerChatCommand, BUFF_PACK, BUFF_PARSER, ITEM_SPECS,
         KIT_MANIFEST_PATH, PRESET_MANIFEST_PATH,
     },
     comp::{
@@ -208,6 +208,10 @@ fn do_command(
         ServerChatCommand::Lightning => handle_lightning,
         ServerChatCommand::Scale => handle_scale,
         ServerChatCommand::RepairEquipment => handle_repair_equipment,
+        ServerChatCommand::Tether => handle_tether,
+        ServerChatCommand::DestroyTethers => handle_destroy_tethers,
+        ServerChatCommand::Mount => handle_mount,
+        ServerChatCommand::Dismount => handle_dismount,
     };
 
     handler(server, client, target, args, cmd)
@@ -1288,9 +1292,9 @@ fn handle_tp(
     args: Vec<String>,
     action: &ServerChatCommand,
 ) -> CmdResult<()> {
-    let (player, dismount_volume) = parse_cmd_args!(args, String, bool);
-    let player = if let Some(alias) = player {
-        find_alias(server.state.ecs(), &alias)?.0
+    let (entity_target, dismount_volume) = parse_cmd_args!(args, EntityTarget, bool);
+    let player = if let Some(entity_target) = entity_target {
+        get_entity_target(entity_target, server)?
     } else if client != target {
         client
     } else {
@@ -1582,6 +1586,17 @@ fn handle_spawn(
         ) => {
             let uid = uid(server, target, "target")?;
             let alignment = parse_alignment(uid, &opt_align)?;
+
+            if matches!(alignment, Alignment::Owned(_))
+                && server
+                    .state
+                    .ecs()
+                    .read_storage::<comp::Anchor>()
+                    .contains(target)
+            {
+                return Err("Spawning this pet would create an anchor chain".into());
+            }
+
             let amount = opt_amount.filter(|x| *x > 0).unwrap_or(1).min(50);
 
             let ai = opt_ai.unwrap_or(true);
@@ -3527,10 +3542,12 @@ fn handle_skill_point(
     args: Vec<String>,
     action: &ServerChatCommand,
 ) -> CmdResult<()> {
-    if let (Some(a_skill_tree), Some(sp), a_alias) = parse_cmd_args!(args, String, u16, String) {
+    if let (Some(a_skill_tree), Some(sp), entity_target) =
+        parse_cmd_args!(args, String, u16, EntityTarget)
+    {
         let skill_tree = parse_skill_tree(&a_skill_tree)?;
-        let player = a_alias
-            .map(|alias| find_alias(server.state.ecs(), &alias).map(|(target, _)| target))
+        let player = entity_target
+            .map(|entity_target| get_entity_target(entity_target, server))
             .unwrap_or(Ok(target))?;
 
         if let Some(mut skill_set) = server
@@ -3542,7 +3559,7 @@ fn handle_skill_point(
             skill_set.add_skill_points(skill_tree, sp);
             Ok(())
         } else {
-            Err("Player has no stats!".into())
+            Err("Entity has no stats!".into())
         }
     } else {
         Err(Content::Plain(action.help_string()))
@@ -3629,6 +3646,37 @@ fn handle_remove_lights(
     Ok(())
 }
 
+fn get_entity_target(entity_target: EntityTarget, server: &Server) -> CmdResult<EcsEntity> {
+    match entity_target {
+        EntityTarget::Player(alias) => Ok(find_alias(server.state.ecs(), &alias)?.0),
+        EntityTarget::RtsimNpc(id) => {
+            let (npc_id, _) = server
+                .state
+                .ecs()
+                .read_resource::<crate::rtsim::RtSim>()
+                .state()
+                .data()
+                .npcs
+                .iter()
+                .find(|(_, npc)| npc.uid == id)
+                .ok_or(Content::Plain(format!(
+                    "Could not find rtsim npc with id {id}."
+                )))?;
+            server
+                .state()
+                .ecs()
+                .read_resource::<common::uid::IdMaps>()
+                .rtsim_entity(common::rtsim::RtSimEntity(npc_id))
+                .ok_or(Content::Plain(format!("Npc with id {id} isn't loaded.")))
+        },
+        EntityTarget::Uid(uid) => server
+            .state
+            .ecs()
+            .entity_from_uid(uid)
+            .ok_or(Content::Plain(format!("{uid:?} not found."))),
+    }
+}
+
 fn handle_sudo(
     server: &mut Server,
     client: EcsEntity,
@@ -3636,23 +3684,34 @@ fn handle_sudo(
     args: Vec<String>,
     action: &ServerChatCommand,
 ) -> CmdResult<()> {
-    if let (Some(player_alias), Some(cmd), cmd_args) =
-        parse_cmd_args!(args, String, String, ..Vec<String>)
+    if let (Some(entity_target), Some(cmd), cmd_args) =
+        parse_cmd_args!(args, EntityTarget, String, ..Vec<String>)
     {
         if let Ok(action) = cmd.parse() {
-            let (player, player_uuid) = find_alias(server.state.ecs(), &player_alias)?;
+            let entity = get_entity_target(entity_target, server)?;
             let client_uuid = uuid(server, client, "client")?;
-            verify_above_role(
-                server,
-                (client, client_uuid),
-                (player, player_uuid),
-                "Cannot sudo players with roles higher than your own.",
-            )?;
+
+            // If the entity target is a player check if client has authority to sudo it.
+            {
+                let players = server.state.ecs().read_storage::<comp::Player>();
+                if let Some(player) = players.get(entity) {
+                    let player_uuid = player.uuid();
+                    drop(players);
+                    verify_above_role(
+                        server,
+                        (client, client_uuid),
+                        (entity, player_uuid),
+                        "Cannot sudo players with roles higher than your own.",
+                    )?;
+                } else if server.entity_admin_role(client) < Some(AdminRole::Admin) {
+                    return Err("You don't have permission to sudo non-players.".into());
+                }
+            }
 
             // TODO: consider making this into a tail call or loop (to avoid the potential
             // stack overflow, although it's less of a risk coming from only mods and
             // admins).
-            do_command(server, client, player, cmd_args, &action)
+            do_command(server, client, entity, cmd_args, &action)
         } else {
             Err(Content::localized("command-unknown"))
         }
@@ -4497,3 +4556,169 @@ fn handle_repair_equipment(
         Err(Content::Plain(action.help_string()))
     }
 }
+
+fn handle_tether(
+    server: &mut Server,
+    _client: EcsEntity,
+    target: EcsEntity,
+    args: Vec<String>,
+    action: &ServerChatCommand,
+) -> CmdResult<()> {
+    enum Either<A, B> {
+        Left(A),
+        Right(B),
+    }
+
+    impl<A: FromStr, B: FromStr> FromStr for Either<A, B> {
+        type Err = B::Err;
+
+        fn from_str(s: &str) -> Result<Self, Self::Err> {
+            A::from_str(s)
+                .map(Either::Left)
+                .or_else(|_| B::from_str(s).map(Either::Right))
+        }
+    }
+    if let (Some(entity_target), length) = parse_cmd_args!(args, EntityTarget, Either<f32, bool>) {
+        let entity_target = get_entity_target(entity_target, server)?;
+
+        let tether_leader = server.state.ecs().uid_from_entity(target);
+        let tether_follower = server.state.ecs().uid_from_entity(entity_target);
+
+        if let (Some(leader), Some(follower)) = (tether_leader, tether_follower) {
+            let base_len = server
+                .state
+                .read_component_cloned::<comp::Body>(target)
+                .map(|b| b.dimensions().y * 1.5 + 1.0)
+                .unwrap_or(6.0);
+            let tether_length = match length {
+                Some(Either::Left(l)) => l.max(0.0) + base_len,
+                Some(Either::Right(true)) => {
+                    let leader_pos = position(server, target, "leader")?;
+                    let follower_pos = position(server, entity_target, "follower")?;
+
+                    leader_pos.0.distance(follower_pos.0) + base_len
+                },
+                _ => base_len,
+            };
+            server
+                .state
+                .link(Tethered {
+                    leader,
+                    follower,
+                    tether_length,
+                })
+                .map_err(|_| "Failed to tether entities".into())
+        } else {
+            Err("Tether members don't have Uids.".into())
+        }
+    } else {
+        Err(Content::Plain(action.help_string()))
+    }
+}
+
+fn handle_destroy_tethers(
+    server: &mut Server,
+    client: EcsEntity,
+    target: EcsEntity,
+    _args: Vec<String>,
+    _action: &ServerChatCommand,
+) -> CmdResult<()> {
+    let mut destroyed = false;
+    destroyed |= server
+        .state
+        .ecs()
+        .write_storage::<Is<common::tether::Leader>>()
+        .remove(target)
+        .is_some();
+    destroyed |= server
+        .state
+        .ecs()
+        .write_storage::<Is<common::tether::Follower>>()
+        .remove(target)
+        .is_some();
+    if destroyed {
+        server.notify_client(
+            client,
+            ServerGeneral::server_msg(
+                ChatType::CommandInfo,
+                Content::localized("command-destroyed-tethers"),
+            ),
+        );
+        Ok(())
+    } else {
+        Err(Content::localized("command-destroyed-no-tethers"))
+    }
+}
+
+fn handle_mount(
+    server: &mut Server,
+    _client: EcsEntity,
+    target: EcsEntity,
+    args: Vec<String>,
+    action: &ServerChatCommand,
+) -> CmdResult<()> {
+    if let Some(entity_target) = parse_cmd_args!(args, EntityTarget) {
+        let entity_target = get_entity_target(entity_target, server)?;
+
+        let rider = server.state.ecs().uid_from_entity(target);
+        let mount = server.state.ecs().uid_from_entity(entity_target);
+
+        if let (Some(rider), Some(mount)) = (rider, mount) {
+            server
+                .state
+                .link(common::mounting::Mounting { mount, rider })
+                .map_err(|_| "Failed to mount entities".into())
+        } else {
+            Err("Mount and/or rider doesn't have an Uid component.".into())
+        }
+    } else {
+        Err(Content::Plain(action.help_string()))
+    }
+}
+
+fn handle_dismount(
+    server: &mut Server,
+    client: EcsEntity,
+    target: EcsEntity,
+    _args: Vec<String>,
+    _action: &ServerChatCommand,
+) -> CmdResult<()> {
+    let mut destroyed = false;
+    destroyed |= server
+        .state
+        .ecs()
+        .write_storage::<Is<common::mounting::Rider>>()
+        .remove(target)
+        .is_some();
+    destroyed |= server
+        .state
+        .ecs()
+        .write_storage::<Is<common::mounting::VolumeRider>>()
+        .remove(target)
+        .is_some();
+    destroyed |= server
+        .state
+        .ecs()
+        .write_storage::<Is<common::mounting::Mount>>()
+        .remove(target)
+        .is_some();
+    destroyed |= server
+        .state
+        .ecs()
+        .write_storage::<common::mounting::VolumeRiders>()
+        .get_mut(target)
+        .map_or(false, |volume_riders| volume_riders.clear());
+
+    if destroyed {
+        server.notify_client(
+            client,
+            ServerGeneral::server_msg(
+                ChatType::CommandInfo,
+                Content::localized("command-dismounted"),
+            ),
+        );
+        Ok(())
+    } else {
+        Err(Content::localized("command-no-dismount"))
+    }
+}

server/src/state_ext.rs

@@ -31,6 +31,7 @@ use common::{
     resources::{Secs, Time, TimeOfDay},
     rtsim::{Actor, RtSimEntity},
     slowjob::SlowJobPool,
+    tether::Tethered,
     uid::{IdMaps, Uid},
     util::Dir,
     LoadoutBuilder, ViewDistances,
@@ -1164,6 +1165,7 @@ impl StateExt for State {
 
         maintain_link::<Mounting>(self);
         maintain_link::<VolumeMounting>(self);
+        maintain_link::<Tethered>(self);
     }
 
     fn delete_entity_recorded(

voxygen/src/cmd.rs

@@ -1,12 +1,25 @@
 use std::str::FromStr;
 
 use crate::{
-    render::ExperimentalShader, session::settings_change::change_render_mode, GlobalState,
+    render::ExperimentalShader,
+    session::{settings_change::change_render_mode, SessionState},
+    GlobalState,
 };
 use client::Client;
-use common::{cmd::*, comp::Admin, parse_cmd_args, uuid::Uuid};
+use common::{
+    cmd::*,
+    comp::Admin,
+    link::Is,
+    mounting::{Mount, Rider, VolumeRider},
+    parse_cmd_args,
+    resources::PlayerEntity,
+    uid::Uid,
+    uuid::Uuid,
+};
+use common_net::sync::WorldSyncExt;
 use levenshtein::levenshtein;
-use strum::IntoEnumIterator;
+use specs::{Join, WorldExt};
+use strum::{EnumIter, IntoEnumIterator};
 
 // Please keep this sorted alphabetically, same as with server commands :-)
 #[derive(Clone, Copy, strum::EnumIter)]
@@ -78,6 +91,7 @@ impl ClientChatCommand {
             .iter()
             .map(|arg| match arg {
                 ArgumentSpec::PlayerName(_) => "{}",
+                ArgumentSpec::EntityTarget(_) => "{}",
                 ArgumentSpec::SiteName(_) => "{/.*/}",
                 ArgumentSpec::Float(_, _, _) => "{}",
                 ArgumentSpec::Integer(_, _, _) => "{d}",
@@ -142,27 +156,155 @@ impl FromStr for ChatCommandKind {
 /// text color
 type CommandResult = Result<Option<String>, String>;
 
+#[derive(EnumIter)]
+enum ClientEntityTarget {
+    Target,
+    Selected,
+    Viewpoint,
+    Mount,
+    Rider,
+    TargetSelf,
+}
+
+impl ClientEntityTarget {
+    const PREFIX: char = '@';
+
+    fn keyword(&self) -> &'static str {
+        match self {
+            ClientEntityTarget::Target => "target",
+            ClientEntityTarget::Selected => "selected",
+            ClientEntityTarget::Viewpoint => "viewpoint",
+            ClientEntityTarget::Mount => "mount",
+            ClientEntityTarget::Rider => "rider",
+            ClientEntityTarget::TargetSelf => "self",
+        }
+    }
+}
+
+fn preproccess_command(
+    session_state: &mut SessionState,
+    command: &ChatCommandKind,
+    args: &mut [String],
+) -> CommandResult {
+    let mut cmd_args = match command {
+        ChatCommandKind::Client(cmd) => cmd.data().args,
+        ChatCommandKind::Server(cmd) => cmd.data().args,
+    };
+    let client = &mut session_state.client.borrow_mut();
+    let ecs = client.state().ecs();
+    let player = ecs.read_resource::<PlayerEntity>().0;
+    let mut command_start = 0;
+    for (i, arg) in args.iter_mut().enumerate() {
+        let mut could_be_entity_target = false;
+        if let Some(post_cmd_args) = cmd_args.get(i - command_start..) {
+            for (j, arg_spec) in post_cmd_args.iter().enumerate() {
+                match arg_spec {
+                    ArgumentSpec::EntityTarget(_) => could_be_entity_target = true,
+                    ArgumentSpec::SubCommand => {
+                        if let Some(sub_command) =
+                            ServerChatCommand::iter().find(|cmd| cmd.keyword() == arg)
+                        {
+                            cmd_args = sub_command.data().args;
+                            command_start = i + j + 1;
+                            break;
+                        }
+                    },
+                    _ => {},
+                }
+                if matches!(arg_spec.requirement(), Requirement::Required) {
+                    break;
+                }
+            }
+        } else if matches!(cmd_args.last(), Some(ArgumentSpec::SubCommand)) {
+            could_be_entity_target = true;
+        }
+        if could_be_entity_target && arg.starts_with(ClientEntityTarget::PREFIX) {
+            let target_str = arg.trim_start_matches(ClientEntityTarget::PREFIX);
+            let target = ClientEntityTarget::iter()
+                .find(|t| t.keyword() == target_str)
+                .ok_or_else(|| {
+                    let help_string = ClientEntityTarget::iter()
+                        .map(|t| t.keyword().to_string())
+                        .reduce(|a, b| format!("{a}/{b}"))
+                        .unwrap_or_default();
+                    format!("Expected {help_string} after '@' found {target_str}")
+                })?;
+            let uid = match target {
+                ClientEntityTarget::Target => session_state
+                    .target_entity
+                    .and_then(|e| ecs.uid_from_entity(e))
+                    .ok_or("Not looking at a valid target".to_string())?,
+                ClientEntityTarget::Selected => session_state
+                    .selected_entity
+                    .and_then(|(e, _)| ecs.uid_from_entity(e))
+                    .ok_or("You don't have a valid target selected".to_string())?,
+                ClientEntityTarget::Viewpoint => session_state
+                    .viewpoint_entity
+                    .and_then(|e| ecs.uid_from_entity(e))
+                    .ok_or("Not viewing from a valid viewpoint entity".to_string())?,
+                ClientEntityTarget::Mount => {
+                    if let Some(player) = player {
+                        ecs.read_storage::<Is<Rider>>()
+                            .get(player)
+                            .map(|is_rider| is_rider.mount)
+                            .or(ecs.read_storage::<Is<VolumeRider>>().get(player).and_then(
+                                |is_rider| match is_rider.pos.kind {
+                                    common::mounting::Volume::Terrain => None,
+                                    common::mounting::Volume::Entity(uid) => Some(uid),
+                                },
+                            ))
+                            .ok_or("Not riding a valid entity".to_string())?
+                    } else {
+                        return Err("No player entity".to_string());
+                    }
+                },
+                ClientEntityTarget::Rider => {
+                    if let Some(player) = player {
+                        ecs.read_storage::<Is<Mount>>()
+                            .get(player)
+                            .map(|is_mount| is_mount.rider)
+                            .ok_or("No valid rider".to_string())?
+                    } else {
+                        return Err("No player entity".to_string());
+                    }
+                },
+                ClientEntityTarget::TargetSelf => player
+                    .and_then(|e| ecs.uid_from_entity(e))
+                    .ok_or("No player entity")?,
+            };
+            let uid = u64::from(uid);
+            *arg = format!("uid@{uid}");
+        }
+    }
+
+    Ok(None)
+}
+
 /// Runs a command by either sending it to the server or processing it
 /// locally. Returns a String to be output to the chat.
 // Note: it's not clear what data future commands will need access to, so the
 // signature of this function might change
 pub fn run_command(
-    client: &mut Client,
+    session_state: &mut SessionState,
     global_state: &mut GlobalState,
     cmd: &str,
-    args: Vec<String>,
+    mut args: Vec<String>,
 ) -> CommandResult {
-    let command = ChatCommandKind::from_str(cmd);
+    let command = ChatCommandKind::from_str(cmd)
+        .map_err(|_| invalid_command_message(&session_state.client.borrow(), cmd.to_string()))?;
+
+    preproccess_command(session_state, &command, &mut args)?;
+
+    let client = &mut session_state.client.borrow_mut();
 
     match command {
-        Ok(ChatCommandKind::Server(cmd)) => {
+        ChatCommandKind::Server(cmd) => {
             client.send_command(cmd.keyword().into(), args);
             Ok(None) // The server will provide a response when the command is run
         },
-        Ok(ChatCommandKind::Client(cmd)) => {
+        ChatCommandKind::Client(cmd) => {
             Ok(Some(run_client_command(client, global_state, cmd, args)?))
         },
-        Err(()) => Err(invalid_command_message(client, cmd.to_string())),
     }
 }
 
@@ -383,6 +525,47 @@ impl TabComplete for ArgumentSpec {
     fn complete(&self, part: &str, client: &Client) -> Vec<String> {
         match self {
             ArgumentSpec::PlayerName(_) => complete_player(part, client),
+            ArgumentSpec::EntityTarget(_) => {
+                if let Some((spec, end)) = part.split_once(ClientEntityTarget::PREFIX) {
+                    match spec {
+                        "" => ClientEntityTarget::iter()
+                            .filter_map(|target| {
+                                let ident = target.keyword();
+                                if ident.starts_with(end) {
+                                    Some(format!("@{ident}"))
+                                } else {
+                                    None
+                                }
+                            })
+                            .collect(),
+                        "uid" => {
+                            if let Some(end) =
+                                u64::from_str(end).ok().or(end.is_empty().then_some(0))
+                            {
+                                client
+                                    .state()
+                                    .ecs()
+                                    .read_storage::<Uid>()
+                                    .join()
+                                    .filter_map(|uid| {
+                                        let uid = u64::from(*uid);
+                                        if end < uid {
+                                            Some(format!("uid@{uid}"))
+                                        } else {
+                                            None
+                                        }
+                                    })
+                                    .collect()
+                            } else {
+                                vec![]
+                            }
+                        },
+                        _ => vec![],
+                    }
+                } else {
+                    complete_player(part, client)
+                }
+            },
             ArgumentSpec::SiteName(_) => complete_site(part, client),
             ArgumentSpec::Float(_, x, _) => {
                 if part.is_empty() {

voxygen/src/session/mod.rs

@@ -90,7 +90,7 @@ enum TickAction {
 
 pub struct SessionState {
     scene: Scene,
-    client: Rc<RefCell<Client>>,
+    pub(crate) client: Rc<RefCell<Client>>,
     metadata: UpdateCharacterMetadata,
     hud: Hud,
     key_state: KeyState,
@@ -104,9 +104,9 @@ pub struct SessionState {
     camera_clamp: bool,
     zoom_lock: bool,
     is_aiming: bool,
-    target_entity: Option<specs::Entity>,
-    selected_entity: Option<(specs::Entity, std::time::Instant)>,
-    viewpoint_entity: Option<specs::Entity>,
+    pub(crate) target_entity: Option<specs::Entity>,
+    pub(crate) selected_entity: Option<(specs::Entity, std::time::Instant)>,
+    pub(crate) viewpoint_entity: Option<specs::Entity>,
     interactable: Option<Interactable>,
     #[cfg(not(target_os = "macos"))]
     mumble_link: SharedLink,
@@ -1530,8 +1530,7 @@ impl PlayState for SessionState {
                         self.client.borrow_mut().send_chat(msg);
                     },
                     HudEvent::SendCommand(name, args) => {
-                        match run_command(&mut self.client.borrow_mut(), global_state, &name, args)
-                        {
+                        match run_command(self, global_state, &name, args) {
                             Ok(Some(info)) => {
                                 // TODO: Localise
                                 self.hud