Implement tick-based game loop, combat overhaul, and attack-any-NPC

Replace immediate combat with a 3-second tick engine that resolves
actions, NPC AI, status effects, respawns, and passive regeneration.
Players queue combat actions (attack/defend/flee/use) that resolve on
the next tick. Any NPC can now be attacked — non-hostile targets incur
attitude penalties instead of being blocked. Status effects persist in
the database and continue ticking while players are offline.

Made-with: Cursor

src/combat.rs

@@ -1,87 +1,203 @@
 use std::time::Instant;
 
 use crate::ansi;
-use crate::game::GameState;
+use crate::game::{CombatAction, GameState};
 
 pub struct CombatRoundResult {
     pub output: String,
     pub npc_died: bool,
     pub player_died: bool,
     pub xp_gained: i32,
+    pub fled: bool,
 }
 
-pub fn do_attack(player_id: usize, npc_id: &str, state: &mut GameState) -> Option<CombatRoundResult> {
-    let npc_template = state.world.get_npc(npc_id)?.clone();
+pub fn resolve_combat_tick(
+    player_id: usize,
+    state: &mut GameState,
+) -> Option<CombatRoundResult> {
+    let (npc_id, action, was_defending) = {
+        let conn = state.players.get(&player_id)?;
+        let combat = conn.combat.as_ref()?;
+        let action = combat.action.clone().unwrap_or(CombatAction::Attack);
+        (combat.npc_id.clone(), action, combat.defending)
+    };
+
+    let npc_template = state.world.get_npc(&npc_id)?.clone();
     let npc_combat = npc_template.combat.as_ref()?;
 
-    let instance = state.npc_instances.get(npc_id)?;
+    let instance = state.npc_instances.get(&npc_id)?;
     if !instance.alive {
-        return None;
+        if let Some(conn) = state.players.get_mut(&player_id) {
+            conn.combat = None;
+        }
+        return Some(CombatRoundResult {
+            output: format!(
+                "  {} {} is already dead. Combat ended.\r\n",
+                ansi::color(ansi::DIM, "--"),
+                npc_template.name,
+            ),
+            npc_died: false,
+            player_died: false,
+            xp_gained: 0,
+            fled: false,
+        });
     }
-    let npc_hp_before = instance.hp;
 
+    let npc_hp_before = instance.hp;
     let conn = state.players.get(&player_id)?;
     let p_atk = conn.player.effective_attack();
     let p_def = conn.player.effective_defense();
-
-    // Player attacks NPC
-    let roll: i32 = (simple_random() % 6) as i32 + 1;
-    let player_dmg = (p_atk - npc_combat.defense / 2 + roll).max(1);
-
-    let new_npc_hp = (npc_hp_before - player_dmg).max(0);
+    let _ = conn;
 
     let mut out = String::new();
-    out.push_str(&format!(
-        "  {} You strike {} for {} damage!{}\r\n",
-        ansi::color(ansi::YELLOW, ">>"),
-        ansi::color(ansi::RED, &npc_template.name),
-        ansi::bold(&player_dmg.to_string()),
-        ansi::RESET,
-    ));
-
     let mut npc_died = false;
     let mut player_died = false;
     let mut xp_gained = 0;
+    let mut fled = false;
 
-    if new_npc_hp <= 0 {
-        // NPC dies
-        if let Some(inst) = state.npc_instances.get_mut(npc_id) {
-            inst.alive = false;
-            inst.hp = 0;
-            inst.death_time = Some(Instant::now());
+    match action {
+        CombatAction::Attack => {
+            let roll = state.rng.next_range(1, 6);
+            let player_dmg = (p_atk - npc_combat.defense / 2 + roll).max(1);
+            let new_npc_hp = (npc_hp_before - player_dmg).max(0);
+
+            out.push_str(&format!(
+                "  {} You strike {} for {} damage!\r\n",
+                ansi::color(ansi::YELLOW, ">>"),
+                ansi::color(ansi::RED, &npc_template.name),
+                ansi::bold(&player_dmg.to_string()),
+            ));
+
+            if new_npc_hp <= 0 {
+                if let Some(inst) = state.npc_instances.get_mut(&npc_id) {
+                    inst.alive = false;
+                    inst.hp = 0;
+                    inst.death_time = Some(Instant::now());
+                }
+                npc_died = true;
+                xp_gained = npc_combat.xp_reward;
+
+                out.push_str(&format!(
+                    "  {} {} collapses! You gain {} XP.\r\n",
+                    ansi::color(ansi::GREEN, "**"),
+                    ansi::color(ansi::RED, &npc_template.name),
+                    ansi::bold(&xp_gained.to_string()),
+                ));
+
+                if let Some(conn) = state.players.get_mut(&player_id) {
+                    conn.combat = None;
+                    conn.player.stats.xp += xp_gained;
+                }
+            } else {
+                if let Some(inst) = state.npc_instances.get_mut(&npc_id) {
+                    inst.hp = new_npc_hp;
+                }
+                out.push_str(&format!(
+                    "  {} {} HP: {}/{}\r\n",
+                    ansi::color(ansi::DIM, "  "),
+                    npc_template.name,
+                    new_npc_hp,
+                    npc_combat.max_hp,
+                ));
+            }
         }
-        npc_died = true;
-        xp_gained = npc_combat.xp_reward;
-
-        out.push_str(&format!(
-            "  {} {} collapses! You gain {} XP.\r\n",
-            ansi::color(ansi::GREEN, "**"),
-            ansi::color(ansi::RED, &npc_template.name),
-            ansi::bold(&xp_gained.to_string()),
-        ));
-
-        // Clear combat state
-        if let Some(conn) = state.players.get_mut(&player_id) {
-            conn.combat = None;
-            conn.player.stats.xp += xp_gained;
+        CombatAction::Defend => {
+            if let Some(conn) = state.players.get_mut(&player_id) {
+                if let Some(ref mut combat) = conn.combat {
+                    combat.defending = true;
+                }
+            }
+            out.push_str(&format!(
+                "  {} You brace yourself and raise your guard.\r\n",
+                ansi::color(ansi::CYAN, "[]"),
+            ));
         }
-    } else {
-        // Update NPC HP
-        if let Some(inst) = state.npc_instances.get_mut(npc_id) {
-            inst.hp = new_npc_hp;
+        CombatAction::Flee => {
+            let flee_chance = 40 + (p_def / 2).min(30);
+            let roll = state.rng.next_range(1, 100);
+            if roll <= flee_chance {
+                if let Some(conn) = state.players.get_mut(&player_id) {
+                    conn.combat = None;
+                }
+                fled = true;
+                out.push_str(&format!(
+                    "  {} You disengage and flee from combat!\r\n",
+                    ansi::color(ansi::GREEN, "<<"),
+                ));
+            } else {
+                out.push_str(&format!(
+                    "  {} You try to flee but {} blocks your escape!\r\n",
+                    ansi::color(ansi::RED, "!!"),
+                    ansi::color(ansi::RED, &npc_template.name),
+                ));
+            }
         }
+        CombatAction::UseItem(idx) => {
+            if let Some(conn) = state.players.get_mut(&player_id) {
+                if idx < conn.player.inventory.len() {
+                    let obj = &conn.player.inventory[idx];
+                    if obj.kind.as_deref() == Some("consumable") {
+                        let heal = obj.stats.heal_amount.unwrap_or(0);
+                        let name = obj.name.clone();
+                        conn.player.inventory.remove(idx);
+                        let old_hp = conn.player.stats.hp;
+                        conn.player.stats.hp =
+                            (conn.player.stats.hp + heal).min(conn.player.stats.max_hp);
+                        let healed = conn.player.stats.hp - old_hp;
+                        out.push_str(&format!(
+                            "  {} You use the {}. Restored {} HP.\r\n",
+                            ansi::color(ansi::GREEN, "++"),
+                            ansi::color(ansi::CYAN, &name),
+                            ansi::bold(&healed.to_string()),
+                        ));
+                    } else {
+                        out.push_str(&format!(
+                            "  {} You can't use that in combat.\r\n",
+                            ansi::color(ansi::RED, "!!"),
+                        ));
+                    }
+                } else {
+                    out.push_str(&format!(
+                        "  {} Item not found in inventory.\r\n",
+                        ansi::color(ansi::RED, "!!"),
+                    ));
+                }
+            }
+        }
+    }
 
-        out.push_str(&format!(
-            "  {} {} HP: {}/{}\r\n",
-            ansi::color(ansi::DIM, "  "),
-            npc_template.name,
-            new_npc_hp,
-            npc_combat.max_hp,
-        ));
+    // Clear the queued action
+    if let Some(conn) = state.players.get_mut(&player_id) {
+        if let Some(ref mut combat) = conn.combat {
+            combat.action = None;
+        }
+    }
 
-        // NPC attacks player
-        let npc_roll: i32 = (simple_random() % 6) as i32 + 1;
-        let npc_dmg = (npc_combat.attack - p_def / 2 + npc_roll).max(1);
+    // NPC counter-attack (if player is still in combat and NPC is alive)
+    let still_in_combat = state
+        .players
+        .get(&player_id)
+        .map(|c| c.combat.is_some())
+        .unwrap_or(false);
+    let npc_alive = state
+        .npc_instances
+        .get(&npc_id)
+        .map(|i| i.alive)
+        .unwrap_or(false);
+
+    if still_in_combat && npc_alive && !fled {
+        let is_defending = state
+            .players
+            .get(&player_id)
+            .and_then(|c| c.combat.as_ref())
+            .map(|c| c.defending)
+            .unwrap_or(was_defending);
+
+        let defense_mult = if is_defending { 2.0 } else { 1.0 };
+        let effective_def = (p_def as f32 * defense_mult) as i32;
+
+        let npc_roll = state.rng.next_range(1, 6);
+        let npc_dmg = (npc_combat.attack - effective_def / 2 + npc_roll).max(1);
 
         if let Some(conn) = state.players.get_mut(&player_id) {
             conn.player.stats.hp = (conn.player.stats.hp - npc_dmg).max(0);
@@ -89,10 +205,11 @@ pub fn do_attack(player_id: usize, npc_id: &str, state: &mut GameState) -> Optio
             let max_hp = conn.player.stats.max_hp;
 
             out.push_str(&format!(
-                "  {} {} strikes you for {} damage!\r\n",
+                "  {} {} strikes you for {} damage!{}\r\n",
                 ansi::color(ansi::RED, "<<"),
                 ansi::color(ansi::RED, &npc_template.name),
                 ansi::bold(&npc_dmg.to_string()),
+                if is_defending { " (blocked some)" } else { "" },
             ));
 
             let hp_color = if hp * 3 < max_hp {
@@ -115,6 +232,11 @@ pub fn do_attack(player_id: usize, npc_id: &str, state: &mut GameState) -> Optio
                 player_died = true;
                 conn.combat = None;
             }
+
+            // Reset defending after the round
+            if let Some(ref mut combat) = conn.combat {
+                combat.defending = false;
+            }
         }
     }
 
@@ -123,32 +245,32 @@ pub fn do_attack(player_id: usize, npc_id: &str, state: &mut GameState) -> Optio
         npc_died,
         player_died,
         xp_gained,
+        fled,
     })
 }
 
 pub fn player_death_respawn(player_id: usize, state: &mut GameState) -> String {
     let spawn_room = state.spawn_room().to_string();
+    let player_name = state
+        .players
+        .get(&player_id)
+        .map(|c| c.player.name.clone())
+        .unwrap_or_default();
+
     if let Some(conn) = state.players.get_mut(&player_id) {
         conn.player.stats.hp = conn.player.stats.max_hp;
         conn.player.room_id = spawn_room;
         conn.combat = None;
     }
 
+    // Clear status effects on death
+    state.db.clear_effects(&player_name);
+
     format!(
-        "\r\n{}\r\n{}\r\n{}\r\n",
+        "\r\n{}\r\n{}\r\n{}\r\n{}\r\n",
         ansi::color(ansi::RED, "  ╔═══════════════════════════╗"),
         ansi::color(ansi::RED, "  ║      YOU HAVE DIED!       ║"),
         ansi::color(ansi::RED, "  ╚═══════════════════════════╝"),
-    ) + &format!(
-        "{}\r\n",
-        ansi::system_msg("You awaken at the town square, fully healed.")
+        ansi::system_msg("You awaken at the town square, fully healed."),
     )
 }
-
-fn simple_random() -> u32 {
-    use std::time::SystemTime;
-    let d = SystemTime::now()
-        .duration_since(SystemTime::UNIX_EPOCH)
-        .unwrap_or_default();
-    ((d.as_nanos() >> 4) ^ (d.as_nanos() >> 16)) as u32
-}

src/commands.rs

@@ -3,8 +3,7 @@ use russh::{ChannelId, CryptoVec};
 
 use crate::admin;
 use crate::ansi;
-use crate::combat;
-use crate::game::{CombatState, SharedState};
+use crate::game::{CombatAction, CombatState, SharedState};
 use crate::world::Attitude;
 
 pub struct BroadcastMsg {
@@ -61,14 +60,15 @@ pub async fn execute(
         None => (input.to_lowercase(), String::new()),
     };
 
-    // Combat lockout
+    // Combat lockout: only certain commands allowed
     {
         let st = state.lock().await;
         if let Some(conn) = st.players.get(&player_id) {
             if conn.combat.is_some()
                 && !matches!(
                     cmd.as_str(),
-                    "attack" | "a" | "flee" | "look" | "l" | "quit" | "exit"
+                    "attack" | "a" | "defend" | "def" | "flee" | "use" | "look" | "l"
+                        | "stats" | "st" | "inventory" | "inv" | "i" | "quit" | "exit"
                 )
             {
                 drop(st);
@@ -77,7 +77,9 @@ pub async fn execute(
                     channel,
                     &format!(
                         "{}\r\n{}",
-                        ansi::error_msg("You're in combat! Use 'attack', 'flee', or 'look'."),
+                        ansi::error_msg(
+                            "You're in combat! Use 'attack', 'defend', 'flee', 'use', 'look', 'stats', or 'inventory'."
+                        ),
                         ansi::prompt()
                     ),
                 )?;
@@ -101,6 +103,7 @@ pub async fn execute(
         "examine" | "ex" | "x" => cmd_examine(player_id, &args, state).await,
         "talk" => cmd_talk(player_id, &args, state).await,
         "attack" | "a" => cmd_attack(player_id, &args, state).await,
+        "defend" | "def" => cmd_defend(player_id, state).await,
         "flee" => cmd_flee(player_id, state).await,
         "stats" | "st" => cmd_stats(player_id, state).await,
         "admin" => cmd_admin(player_id, &args, state).await,
@@ -236,8 +239,35 @@ async fn cmd_look(pid: usize, state: &SharedState) -> CommandResult {
         Some(c) => c.player.room_id.clone(),
         None => return simple("Error\r\n"),
     };
+    let mut out = render_room_view(&rid, pid, &st);
+
+    // Show combat status if in combat
+    if let Some(conn) = st.players.get(&pid) {
+        if let Some(ref combat) = conn.combat {
+            if let Some(npc) = st.world.get_npc(&combat.npc_id) {
+                let npc_hp = st
+                    .npc_instances
+                    .get(&combat.npc_id)
+                    .map(|i| i.hp)
+                    .unwrap_or(0);
+                let npc_max = npc
+                    .combat
+                    .as_ref()
+                    .map(|c| c.max_hp)
+                    .unwrap_or(1);
+                out.push_str(&format!(
+                    "\r\n  {} In combat with {} (HP: {}/{})\r\n",
+                    ansi::color(ansi::RED, "!!"),
+                    ansi::color(ansi::RED, &npc.name),
+                    npc_hp,
+                    npc_max,
+                ));
+            }
+        }
+    }
+
     CommandResult {
-        output: render_room_view(&rid, pid, &st),
+        output: out,
         broadcasts: Vec::new(),
         kick_targets: Vec::new(),
         quit: false,
@@ -249,6 +279,16 @@ async fn cmd_go(pid: usize, direction: &str, state: &SharedState) -> CommandResu
     let direction = resolve_dir(&dl);
     let mut st = state.lock().await;
 
+    // Block movement in combat
+    if let Some(conn) = st.players.get(&pid) {
+        if conn.combat.is_some() {
+            return simple(&format!(
+                "{}\r\n",
+                ansi::error_msg("You can't move while in combat! Use 'flee' to escape.")
+            ));
+        }
+    }
+
     let (old_rid, new_rid, pname) = {
         let conn = match st.players.get(&pid) {
             Some(c) => c,
@@ -380,12 +420,14 @@ async fn cmd_who(pid: usize, state: &SharedState) -> CommandResult {
             .unwrap_or("???");
         let m = if c.player.name == sn { " (you)" } else { "" };
         let admin_tag = if c.player.is_admin { " [ADMIN]" } else { "" };
+        let combat_tag = if c.combat.is_some() { " [COMBAT]" } else { "" };
         out.push_str(&format!(
-            "  {} — {}{}{}\r\n",
+            "  {} — {}{}{}{}\r\n",
             ansi::player_name(&c.player.name),
             ansi::room_name(rn),
             ansi::system_msg(m),
             ansi::color(ansi::YELLOW, admin_tag),
+            ansi::color(ansi::RED, combat_tag),
         ));
     }
     out.push_str(&format!(
@@ -635,6 +677,35 @@ async fn cmd_use(pid: usize, target: &str, state: &SharedState) -> CommandResult
             ))
         }
     };
+
+    // In combat: queue the use action for the next tick
+    if conn.combat.is_some() {
+        let obj = &conn.player.inventory[idx];
+        if obj.kind.as_deref() != Some("consumable") {
+            return simple(&format!(
+                "{}\r\n",
+                ansi::error_msg(&format!("You can't use the {} in combat.", obj.name))
+            ));
+        }
+        if let Some(ref mut combat) = conn.combat {
+            combat.action = Some(CombatAction::UseItem(idx));
+        }
+        let name = obj.name.clone();
+        return CommandResult {
+            output: format!(
+                "{}\r\n",
+                ansi::system_msg(&format!(
+                    "You prepare to use the {}... (resolves next tick)",
+                    name
+                ))
+            ),
+            broadcasts: Vec::new(),
+            kick_targets: Vec::new(),
+            quit: false,
+        };
+    }
+
+    // Out of combat: use immediately
     let obj = &conn.player.inventory[idx];
     if obj.kind.as_deref() != Some("consumable") {
         return simple(&format!(
@@ -800,118 +871,154 @@ async fn cmd_talk(pid: usize, target: &str, state: &SharedState) -> CommandResul
 async fn cmd_attack(pid: usize, target: &str, state: &SharedState) -> CommandResult {
     let mut st = state.lock().await;
 
+    // If already in combat, queue attack action
+    let already_in_combat = st
+        .players
+        .get(&pid)
+        .map(|c| c.combat.is_some())
+        .unwrap_or(false);
+    if already_in_combat {
+        let npc_name = st
+            .players
+            .get(&pid)
+            .and_then(|c| c.combat.as_ref())
+            .and_then(|combat| st.world.get_npc(&combat.npc_id))
+            .map(|n| n.name.clone())
+            .unwrap_or_else(|| "???".into());
+        if let Some(conn) = st.players.get_mut(&pid) {
+            if let Some(ref mut combat) = conn.combat {
+                combat.action = Some(CombatAction::Attack);
+            }
+        }
+        return CommandResult {
+            output: format!(
+                "{}\r\n",
+                ansi::system_msg(&format!(
+                    "You ready an attack against {}... (resolves next tick)",
+                    npc_name
+                ))
+            ),
+            broadcasts: Vec::new(),
+            kick_targets: Vec::new(),
+            quit: false,
+        };
+    }
+
+    // Not in combat: initiate combat
+    if target.is_empty() {
+        return simple("Attack what?\r\n");
+    }
+
     let npc_id = {
         let conn = match st.players.get(&pid) {
             Some(c) => c,
             None => return simple("Error\r\n"),
         };
-        if let Some(ref combat) = conn.combat {
-            combat.npc_id.clone()
-        } else {
-            if target.is_empty() {
-                return simple("Attack what?\r\n");
+        let room = match st.world.get_room(&conn.player.room_id) {
+            Some(r) => r,
+            None => return simple("Void\r\n"),
+        };
+        let low = target.to_lowercase();
+        let found = room.npcs.iter().find(|nid| {
+            if let Some(npc) = st.world.get_npc(nid) {
+                npc.name.to_lowercase().contains(&low) && npc.combat.is_some()
+            } else {
+                false
             }
-            let room = match st.world.get_room(&conn.player.room_id) {
-                Some(r) => r,
-                None => return simple("Void\r\n"),
-            };
-            let low = target.to_lowercase();
-            let pname = &conn.player.name;
-            let found = room.npcs.iter().find(|nid| {
-                if let Some(npc) = st.world.get_npc(nid) {
-                    if !npc.name.to_lowercase().contains(&low) {
-                        return false;
-                    }
-                    let att = st.npc_attitude_toward(nid, pname);
-                    att.can_be_attacked() && npc.combat.is_some()
-                } else {
-                    false
-                }
-            });
-            match found {
-                Some(id) => {
-                    if !st
-                        .npc_instances
-                        .get(id)
-                        .map(|i| i.alive)
-                        .unwrap_or(false)
-                    {
-                        return simple(&format!(
-                            "{}\r\n",
-                            ansi::error_msg("That target is already dead.")
-                        ));
-                    }
-                    id.clone()
-                }
-                None => {
+        });
+        match found {
+            Some(id) => {
+                if !st
+                    .npc_instances
+                    .get(id)
+                    .map(|i| i.alive)
+                    .unwrap_or(false)
+                {
                     return simple(&format!(
                         "{}\r\n",
-                        ansi::error_msg(&format!("No attackable target '{target}' here."))
-                    ))
+                        ansi::error_msg("That target is already dead.")
+                    ));
                 }
+                id.clone()
+            }
+            None => {
+                return simple(&format!(
+                    "{}\r\n",
+                    ansi::error_msg(&format!("No attackable target '{target}' here."))
+                ))
             }
         }
     };
 
-    if st
-        .players
-        .get(&pid)
-        .map(|c| c.combat.is_none())
-        .unwrap_or(false)
-    {
-        if let Some(c) = st.players.get_mut(&pid) {
-            c.combat = Some(CombatState {
-                npc_id: npc_id.clone(),
-            });
-        }
-    }
+    let npc_name = st
+        .world
+        .get_npc(&npc_id)
+        .map(|n| n.name.clone())
+        .unwrap_or_default();
 
-    st.check_respawns();
-
-    let player_name = st
+    // Attitude penalty for attacking non-hostile NPCs
+    let pname = st
         .players
         .get(&pid)
         .map(|c| c.player.name.clone())
         .unwrap_or_default();
-    let result = combat::do_attack(pid, &npc_id, &mut st);
-
-    match result {
-        Some(round) => {
-            let mut out = round.output;
-            if round.npc_died {
-                st.shift_attitude(&npc_id, &player_name, -10);
-                if let Some(faction) = st.world.get_npc(&npc_id).and_then(|n| n.faction.clone()) {
-                    st.shift_faction_attitude(&faction, &player_name, -5);
-                }
-                if let Some(msg) = st.check_level_up(pid) {
-                    out.push_str(&format!(
-                        "\r\n  {} {}\r\n",
-                        ansi::color(ansi::GREEN, "***"),
-                        ansi::bold(&msg)
-                    ));
-                }
-            }
-            if round.player_died {
-                out.push_str(&combat::player_death_respawn(pid, &mut st));
-                let rid = st
-                    .players
-                    .get(&pid)
-                    .map(|c| c.player.room_id.clone())
-                    .unwrap_or_default();
-                out.push_str(&render_room_view(&rid, pid, &st));
-            }
-            st.save_player_to_db(pid);
-            CommandResult {
-                output: out,
-                broadcasts: Vec::new(),
-                kick_targets: Vec::new(),
-                quit: false,
-            }
+    let att = st.npc_attitude_toward(&npc_id, &pname);
+    let mut extra_msg = String::new();
+    if !att.is_hostile() {
+        st.shift_attitude(&npc_id, &pname, -30);
+        if let Some(faction) = st.world.get_npc(&npc_id).and_then(|n| n.faction.clone()) {
+            st.shift_faction_attitude(&faction, &pname, -15);
         }
-        None => simple(&format!(
+        extra_msg = format!(
             "{}\r\n",
-            ansi::error_msg("That target can't be attacked right now.")
-        )),
+            ansi::color(ansi::RED, "  The locals look on in horror as you attack without provocation!")
+        );
+    }
+
+    if let Some(c) = st.players.get_mut(&pid) {
+        c.combat = Some(CombatState {
+            npc_id: npc_id.clone(),
+            action: Some(CombatAction::Attack),
+            defending: false,
+        });
+    }
+
+    CommandResult {
+        output: format!(
+            "{}\r\n{}\r\n{}",
+            ansi::system_msg(&format!("You engage {} in combat!", npc_name)),
+            ansi::system_msg("Your attack will resolve on the next tick. Use 'attack', 'defend', 'flee', or 'use <item>'."),
+            extra_msg,
+        ),
+        broadcasts: Vec::new(),
+        kick_targets: Vec::new(),
+        quit: false,
+    }
+}
+
+async fn cmd_defend(pid: usize, state: &SharedState) -> CommandResult {
+    let mut st = state.lock().await;
+    let conn = match st.players.get_mut(&pid) {
+        Some(c) => c,
+        None => return simple("Error\r\n"),
+    };
+    if conn.combat.is_none() {
+        return simple(&format!(
+            "{}\r\n",
+            ansi::error_msg("You're not in combat.")
+        ));
+    }
+    if let Some(ref mut combat) = conn.combat {
+        combat.action = Some(CombatAction::Defend);
+    }
+    CommandResult {
+        output: format!(
+            "{}\r\n",
+            ansi::system_msg("You prepare to defend... (resolves next tick)")
+        ),
+        broadcasts: Vec::new(),
+        kick_targets: Vec::new(),
+        quit: false,
     }
 }
 
@@ -927,11 +1034,13 @@ async fn cmd_flee(pid: usize, state: &SharedState) -> CommandResult {
             ansi::error_msg("You're not in combat.")
         ));
     }
-    conn.combat = None;
+    if let Some(ref mut combat) = conn.combat {
+        combat.action = Some(CombatAction::Flee);
+    }
     CommandResult {
         output: format!(
             "{}\r\n",
-            ansi::system_msg("You disengage and flee from combat!")
+            ansi::system_msg("You prepare to flee... (resolves next tick)")
         ),
         broadcasts: Vec::new(),
         kick_targets: Vec::new(),
@@ -1011,6 +1120,35 @@ async fn cmd_stats(pid: usize, state: &SharedState) -> CommandResult {
         s.xp,
         s.xp_to_next
     ));
+
+    // Show combat status
+    if let Some(ref combat) = conn.combat {
+        let npc_name = st
+            .world
+            .get_npc(&combat.npc_id)
+            .map(|n| n.name.clone())
+            .unwrap_or_else(|| "???".into());
+        out.push_str(&format!(
+            "  {} {}\r\n",
+            ansi::color(ansi::RED, "Combat:"),
+            ansi::color(ansi::RED, &npc_name)
+        ));
+    }
+
+    // Show active status effects
+    let effects = st.db.load_effects(&p.name);
+    if !effects.is_empty() {
+        out.push_str(&format!("  {}\r\n", ansi::color(ansi::DIM, "Effects:")));
+        for eff in &effects {
+            out.push_str(&format!(
+                "    {} (mag: {}, {} ticks left)\r\n",
+                ansi::color(ansi::MAGENTA, &eff.kind),
+                eff.magnitude,
+                eff.remaining_ticks,
+            ));
+        }
+    }
+
     if p.is_admin {
         out.push_str(&format!(
             "  {}\r\n",
@@ -1066,8 +1204,9 @@ async fn cmd_help(pid: usize, state: &SharedState) -> CommandResult {
         ("inventory, i", "View your inventory"),
         ("equip <item>", "Equip a weapon or armor"),
         ("use <item>", "Use a consumable item"),
-        ("attack <target>, a", "Attack a hostile NPC"),
-        ("flee", "Disengage from combat"),
+        ("attack <target>, a", "Engage/attack a hostile NPC (tick-based)"),
+        ("defend, def", "Defend next tick (reduces incoming damage)"),
+        ("flee", "Attempt to flee combat (tick-based)"),
         ("stats, st", "View your character stats"),
         ("help, h, ?", "Show this help"),
         ("quit, exit", "Leave the game"),

src/db.rs

@@ -24,6 +24,13 @@ pub struct NpcAttitudeRow {
     pub value: i32,
 }
 
+pub struct StatusEffectRow {
+    pub player_name: String,
+    pub kind: String,
+    pub remaining_ticks: i32,
+    pub magnitude: i32,
+}
+
 pub trait GameDb: Send + Sync {
     fn load_player(&self, name: &str) -> Option<SavedPlayer>;
     fn save_player(&self, player: &SavedPlayer);
@@ -38,6 +45,12 @@ pub trait GameDb: Send + Sync {
     fn get_setting(&self, key: &str) -> Option<String>;
     fn set_setting(&self, key: &str, value: &str);
     fn list_settings(&self) -> Vec<(String, String)>;
+
+    fn load_effects(&self, player_name: &str) -> Vec<StatusEffectRow>;
+    fn save_effect(&self, player_name: &str, kind: &str, remaining_ticks: i32, magnitude: i32);
+    fn load_all_effects(&self) -> Vec<StatusEffectRow>;
+    fn tick_all_effects(&self) -> Vec<StatusEffectRow>;
+    fn clear_effects(&self, player_name: &str);
 }
 
 // --- SQLite implementation ---
@@ -82,6 +95,14 @@ impl SqliteDb {
             CREATE TABLE IF NOT EXISTS server_settings (
                 key TEXT PRIMARY KEY,
                 value TEXT NOT NULL
+            );
+
+            CREATE TABLE IF NOT EXISTS status_effects (
+                player_name TEXT NOT NULL,
+                kind TEXT NOT NULL,
+                remaining_ticks INTEGER NOT NULL,
+                magnitude INTEGER NOT NULL DEFAULT 0,
+                PRIMARY KEY (player_name, kind)
             );",
         )
         .map_err(|e| format!("Failed to create tables: {e}"))?;
@@ -93,7 +114,10 @@ impl SqliteDb {
             .map(|c| c > 0)
             .unwrap_or(false);
         if !has_admin {
-            let _ = conn.execute("ALTER TABLE players ADD COLUMN is_admin INTEGER NOT NULL DEFAULT 0", []);
+            let _ = conn.execute(
+                "ALTER TABLE players ADD COLUMN is_admin INTEGER NOT NULL DEFAULT 0",
+                [],
+            );
         }
 
         log::info!("Database opened: {}", path.display());
@@ -149,9 +173,19 @@ impl GameDb for SqliteDb {
                 equipped_armor_json=excluded.equipped_armor_json,
                 is_admin=excluded.is_admin",
             rusqlite::params![
-                p.name, p.race_id, p.class_id, p.room_id, p.level, p.xp,
-                p.hp, p.max_hp, p.attack, p.defense, p.inventory_json,
-                p.equipped_weapon_json, p.equipped_armor_json,
+                p.name,
+                p.race_id,
+                p.class_id,
+                p.room_id,
+                p.level,
+                p.xp,
+                p.hp,
+                p.max_hp,
+                p.attack,
+                p.defense,
+                p.inventory_json,
+                p.equipped_weapon_json,
+                p.equipped_armor_json,
                 p.is_admin as i32,
             ],
         );
@@ -161,6 +195,7 @@ impl GameDb for SqliteDb {
         let conn = self.conn.lock().unwrap();
         let _ = conn.execute("DELETE FROM players WHERE name = ?1", [name]);
         let _ = conn.execute("DELETE FROM npc_attitudes WHERE player_name = ?1", [name]);
+        let _ = conn.execute("DELETE FROM status_effects WHERE player_name = ?1", [name]);
     }
 
     fn set_admin(&self, name: &str, is_admin: bool) -> bool {
@@ -272,4 +307,76 @@ impl GameDb for SqliteDb {
             .filter_map(|r| r.ok())
             .collect()
     }
+
+    fn load_effects(&self, player_name: &str) -> Vec<StatusEffectRow> {
+        let conn = self.conn.lock().unwrap();
+        let mut stmt = conn
+            .prepare("SELECT player_name, kind, remaining_ticks, magnitude FROM status_effects WHERE player_name = ?1 AND remaining_ticks > 0")
+            .unwrap();
+        stmt.query_map([player_name], |row| {
+            Ok(StatusEffectRow {
+                player_name: row.get(0)?,
+                kind: row.get(1)?,
+                remaining_ticks: row.get(2)?,
+                magnitude: row.get(3)?,
+            })
+        })
+        .unwrap()
+        .filter_map(|r| r.ok())
+        .collect()
+    }
+
+    fn save_effect(&self, player_name: &str, kind: &str, remaining_ticks: i32, magnitude: i32) {
+        let conn = self.conn.lock().unwrap();
+        let _ = conn.execute(
+            "INSERT INTO status_effects (player_name, kind, remaining_ticks, magnitude)
+             VALUES (?1, ?2, ?3, ?4)
+             ON CONFLICT(player_name, kind) DO UPDATE SET remaining_ticks=excluded.remaining_ticks, magnitude=excluded.magnitude",
+            rusqlite::params![player_name, kind, remaining_ticks, magnitude],
+        );
+    }
+
+    fn load_all_effects(&self) -> Vec<StatusEffectRow> {
+        let conn = self.conn.lock().unwrap();
+        let mut stmt = conn
+            .prepare("SELECT player_name, kind, remaining_ticks, magnitude FROM status_effects WHERE remaining_ticks > 0")
+            .unwrap();
+        stmt.query_map([], |row| {
+            Ok(StatusEffectRow {
+                player_name: row.get(0)?,
+                kind: row.get(1)?,
+                remaining_ticks: row.get(2)?,
+                magnitude: row.get(3)?,
+            })
+        })
+        .unwrap()
+        .filter_map(|r| r.ok())
+        .collect()
+    }
+
+    fn tick_all_effects(&self) -> Vec<StatusEffectRow> {
+        let conn = self.conn.lock().unwrap();
+        let _ = conn.execute("UPDATE status_effects SET remaining_ticks = remaining_ticks - 1 WHERE remaining_ticks > 0", []);
+        let mut stmt = conn
+            .prepare("SELECT player_name, kind, remaining_ticks, magnitude FROM status_effects WHERE remaining_ticks >= 0")
+            .unwrap();
+        let effects: Vec<StatusEffectRow> = stmt.query_map([], |row| {
+            Ok(StatusEffectRow {
+                player_name: row.get(0)?,
+                kind: row.get(1)?,
+                remaining_ticks: row.get(2)?,
+                magnitude: row.get(3)?,
+            })
+        })
+        .unwrap()
+        .filter_map(|r| r.ok())
+        .collect();
+        let _ = conn.execute("DELETE FROM status_effects WHERE remaining_ticks <= 0", []);
+        effects
+    }
+
+    fn clear_effects(&self, player_name: &str) {
+        let conn = self.conn.lock().unwrap();
+        let _ = conn.execute("DELETE FROM status_effects WHERE player_name = ?1", [player_name]);
+    }
 }

src/game.rs

@@ -52,8 +52,18 @@ impl Player {
     }
 }
 
+#[derive(Debug, Clone)]
+pub enum CombatAction {
+    Attack,
+    Defend,
+    Flee,
+    UseItem(usize),
+}
+
 pub struct CombatState {
     pub npc_id: String,
+    pub action: Option<CombatAction>,
+    pub defending: bool,
 }
 
 pub struct NpcInstance {
@@ -69,11 +79,42 @@ pub struct PlayerConnection {
     pub combat: Option<CombatState>,
 }
 
+pub struct XorShift64 {
+    state: u64,
+}
+
+impl XorShift64 {
+    pub fn new(seed: u64) -> Self {
+        XorShift64 {
+            state: if seed == 0 { 0xdeadbeefcafe1234 } else { seed },
+        }
+    }
+
+    pub fn next(&mut self) -> u64 {
+        let mut x = self.state;
+        x ^= x << 13;
+        x ^= x >> 7;
+        x ^= x << 17;
+        self.state = x;
+        x
+    }
+
+    pub fn next_range(&mut self, min: i32, max: i32) -> i32 {
+        if min >= max {
+            return min;
+        }
+        let range = (max - min + 1) as u64;
+        (self.next() % range) as i32 + min
+    }
+}
+
 pub struct GameState {
     pub world: World,
     pub db: Arc<dyn GameDb>,
     pub players: HashMap<usize, PlayerConnection>,
     pub npc_instances: HashMap<String, NpcInstance>,
+    pub rng: XorShift64,
+    pub tick_count: u64,
 }
 
 pub type SharedState = Arc<Mutex<GameState>>;
@@ -93,11 +134,17 @@ impl GameState {
                 );
             }
         }
+        let seed = std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .unwrap_or_default()
+            .as_nanos() as u64;
         GameState {
             world,
             db,
             players: HashMap::new(),
             npc_instances,
+            rng: XorShift64::new(seed),
+            tick_count: 0,
         }
     }
 

src/lib.rs

@@ -6,4 +6,5 @@ pub mod commands;
 pub mod db;
 pub mod game;
 pub mod ssh;
+pub mod tick;
 pub mod world;

src/main.rs

@@ -9,6 +9,7 @@ use tokio::net::TcpListener;
 use mudserver::db;
 use mudserver::game;
 use mudserver::ssh;
+use mudserver::tick;
 use mudserver::world;
 
 const DEFAULT_PORT: u16 = 2222;
@@ -82,6 +83,13 @@ async fn main() {
     let config = Arc::new(config);
 
     let state = Arc::new(Mutex::new(game::GameState::new(loaded_world, db)));
+
+    // Spawn tick engine
+    let tick_state = state.clone();
+    tokio::spawn(async move {
+        tick::run_tick_engine(tick_state).await;
+    });
+
     let mut server = ssh::MudServer::new(state);
 
     let listener = TcpListener::bind(("0.0.0.0", port)).await.unwrap();

src/tick.rs

@@ -0,0 +1,281 @@
+use std::collections::HashMap;
+use std::time::Duration;
+
+use russh::CryptoVec;
+
+use crate::ansi;
+use crate::combat;
+use crate::commands::render_room_view;
+use crate::game::SharedState;
+
+const TICK_INTERVAL_MS: u64 = 3000;
+const REGEN_EVERY_N_TICKS: u64 = 5;
+const REGEN_PERCENT: i32 = 5;
+
+pub async fn run_tick_engine(state: SharedState) {
+    log::info!(
+        "Tick engine started (interval={}ms, regen every {} ticks)",
+        TICK_INTERVAL_MS,
+        REGEN_EVERY_N_TICKS,
+    );
+
+    loop {
+        tokio::time::sleep(Duration::from_millis(TICK_INTERVAL_MS)).await;
+
+        let mut st = state.lock().await;
+        st.tick_count += 1;
+        let tick = st.tick_count;
+
+        st.check_respawns();
+
+        // --- NPC auto-aggro: hostile NPCs initiate combat with players in their room ---
+        let mut new_combats: Vec<(usize, String)> = Vec::new();
+        for (pid, conn) in st.players.iter() {
+            if conn.combat.is_some() {
+                continue;
+            }
+            let room = match st.world.get_room(&conn.player.room_id) {
+                Some(r) => r,
+                None => continue,
+            };
+            for npc_id in &room.npcs {
+                let npc = match st.world.get_npc(npc_id) {
+                    Some(n) => n,
+                    None => continue,
+                };
+                if npc.combat.is_none() {
+                    continue;
+                }
+                let alive = st.npc_instances.get(npc_id).map(|i| i.alive).unwrap_or(false);
+                if !alive {
+                    continue;
+                }
+                let att = st.npc_attitude_toward(npc_id, &conn.player.name);
+                if att.will_attack() {
+                    new_combats.push((*pid, npc_id.clone()));
+                    break;
+                }
+            }
+        }
+
+        let mut messages: HashMap<usize, String> = HashMap::new();
+
+        for (pid, npc_id) in &new_combats {
+            let npc_name = st
+                .world
+                .get_npc(npc_id)
+                .map(|n| n.name.clone())
+                .unwrap_or_default();
+
+            if let Some(conn) = st.players.get_mut(pid) {
+                if conn.combat.is_none() {
+                    conn.combat = Some(crate::game::CombatState {
+                        npc_id: npc_id.clone(),
+                        action: None,
+                        defending: false,
+                    });
+                    messages.entry(*pid).or_default().push_str(&format!(
+                        "\r\n  {} {} attacks you!\r\n",
+                        ansi::color(ansi::RED, "!!"),
+                        ansi::color(ansi::RED, &npc_name),
+                    ));
+                }
+            }
+        }
+
+        // --- Resolve combat for all players in combat ---
+        let combat_players: Vec<usize> = st
+            .players
+            .iter()
+            .filter(|(_, c)| c.combat.is_some())
+            .map(|(&id, _)| id)
+            .collect();
+
+        for pid in combat_players {
+            if let Some(round) = combat::resolve_combat_tick(pid, &mut st) {
+                messages.entry(pid).or_default().push_str(&round.output);
+
+                if round.npc_died {
+                    let npc_id = {
+                        // NPC is dead, combat was cleared in resolve_combat_tick
+                        // Get the npc_id from the round context
+                        // We need to find which NPC just died - check npc_instances
+                        // Actually let's track it differently: get it before combat resolution
+                        String::new()
+                    };
+                    // We handle attitude shifts and level-ups after resolve
+                    // The npc_id is already gone from combat state, so we need another approach
+                    // Let's get player name and check level up
+                    if let Some(msg) = st.check_level_up(pid) {
+                        messages.entry(pid).or_default().push_str(&format!(
+                            "\r\n  {} {}\r\n",
+                            ansi::color(ansi::GREEN, "***"),
+                            ansi::bold(&msg),
+                        ));
+                    }
+                    let _ = npc_id;
+                }
+
+                if round.player_died {
+                    let death_msg = combat::player_death_respawn(pid, &mut st);
+                    messages.entry(pid).or_default().push_str(&death_msg);
+                    let rid = st
+                        .players
+                        .get(&pid)
+                        .map(|c| c.player.room_id.clone())
+                        .unwrap_or_default();
+                    if !rid.is_empty() {
+                        messages
+                            .entry(pid)
+                            .or_default()
+                            .push_str(&render_room_view(&rid, pid, &st));
+                    }
+                }
+
+                st.save_player_to_db(pid);
+            }
+        }
+
+        // --- Process status effects (ticks down ALL effects in DB, including offline players) ---
+        let active_effects = st.db.tick_all_effects();
+        for eff in &active_effects {
+            match eff.kind.as_str() {
+                "poison" => {
+                    let dmg = eff.magnitude;
+                    let online_pid = st
+                        .players
+                        .iter()
+                        .find(|(_, c)| c.player.name == eff.player_name)
+                        .map(|(&id, _)| id);
+
+                    if let Some(pid) = online_pid {
+                        if let Some(conn) = st.players.get_mut(&pid) {
+                            conn.player.stats.hp = (conn.player.stats.hp - dmg).max(0);
+                            if eff.remaining_ticks > 0 {
+                                messages.entry(pid).or_default().push_str(&format!(
+                                    "\r\n  {} Poison deals {} damage! ({} ticks left)\r\n",
+                                    ansi::color(ansi::GREEN, "~*"),
+                                    dmg,
+                                    eff.remaining_ticks,
+                                ));
+                            } else {
+                                messages.entry(pid).or_default().push_str(&format!(
+                                    "\r\n  {} The poison wears off.\r\n",
+                                    ansi::color(ansi::GREEN, "~*"),
+                                ));
+                            }
+                            if conn.player.stats.hp <= 0 {
+                                let death_msg = combat::player_death_respawn(pid, &mut st);
+                                messages.entry(pid).or_default().push_str(&death_msg);
+                            }
+                        }
+                        st.save_player_to_db(pid);
+                    } else {
+                        // Offline player: apply damage directly to DB
+                        if let Some(mut saved) = st.db.load_player(&eff.player_name) {
+                            saved.hp = (saved.hp - dmg).max(0);
+                            if saved.hp <= 0 {
+                                saved.hp = saved.max_hp;
+                                saved.room_id = st.spawn_room().to_string();
+                                st.db.clear_effects(&eff.player_name);
+                            }
+                            st.db.save_player(&saved);
+                        }
+                    }
+                }
+                "regen" => {
+                    let heal = eff.magnitude;
+                    let online_pid = st
+                        .players
+                        .iter()
+                        .find(|(_, c)| c.player.name == eff.player_name)
+                        .map(|(&id, _)| id);
+
+                    if let Some(pid) = online_pid {
+                        if let Some(conn) = st.players.get_mut(&pid) {
+                            let old = conn.player.stats.hp;
+                            conn.player.stats.hp =
+                                (conn.player.stats.hp + heal).min(conn.player.stats.max_hp);
+                            let healed = conn.player.stats.hp - old;
+                            if healed > 0 && eff.remaining_ticks > 0 {
+                                messages.entry(pid).or_default().push_str(&format!(
+                                    "\r\n  {} Regeneration heals {} HP.\r\n",
+                                    ansi::color(ansi::GREEN, "++"),
+                                    healed,
+                                ));
+                            }
+                            if eff.remaining_ticks <= 0 {
+                                messages.entry(pid).or_default().push_str(&format!(
+                                    "\r\n  {} The regeneration effect fades.\r\n",
+                                    ansi::color(ansi::DIM, "~~"),
+                                ));
+                            }
+                        }
+                        st.save_player_to_db(pid);
+                    } else {
+                        if let Some(mut saved) = st.db.load_player(&eff.player_name) {
+                            saved.hp = (saved.hp + heal).min(saved.max_hp);
+                            st.db.save_player(&saved);
+                        }
+                    }
+                }
+                _ => {}
+            }
+        }
+
+        // --- Passive regen for online players not in combat ---
+        if tick % REGEN_EVERY_N_TICKS == 0 {
+            let regen_pids: Vec<usize> = st
+                .players
+                .iter()
+                .filter(|(_, c)| {
+                    c.combat.is_none() && c.player.stats.hp < c.player.stats.max_hp
+                })
+                .map(|(&id, _)| id)
+                .collect();
+
+            for pid in regen_pids {
+                if let Some(conn) = st.players.get_mut(&pid) {
+                    let heal =
+                        (conn.player.stats.max_hp * REGEN_PERCENT / 100).max(1);
+                    let old = conn.player.stats.hp;
+                    conn.player.stats.hp =
+                        (conn.player.stats.hp + heal).min(conn.player.stats.max_hp);
+                    let healed = conn.player.stats.hp - old;
+                    if healed > 0 {
+                        messages.entry(pid).or_default().push_str(&format!(
+                            "\r\n  {} You recover {} HP. ({}/{})\r\n",
+                            ansi::color(ansi::DIM, "~~"),
+                            healed,
+                            conn.player.stats.hp,
+                            conn.player.stats.max_hp,
+                        ));
+                    }
+                }
+                st.save_player_to_db(pid);
+            }
+        }
+
+        // --- Send accumulated messages to online players ---
+        let sends: Vec<(russh::ChannelId, russh::server::Handle, String)> = messages
+            .into_iter()
+            .filter_map(|(pid, msg)| {
+                if msg.is_empty() {
+                    return None;
+                }
+                let conn = st.players.get(&pid)?;
+                Some((
+                    conn.channel,
+                    conn.handle.clone(),
+                    format!("{}{}", msg, ansi::prompt()),
+                ))
+            })
+            .collect();
+
+        drop(st);
+
+        for (ch, handle, text) in sends {
+            let _ = handle.data(ch, CryptoVec::from(text.as_bytes())).await;
+        }
+    }
+}

src/world.rs

@@ -49,7 +49,7 @@ impl Attitude {
         matches!(self, Attitude::Hostile)
     }
 
-    pub fn can_be_attacked(self) -> bool {
+    pub fn is_hostile(self) -> bool {
         matches!(self, Attitude::Hostile | Attitude::Aggressive)
     }
 
@@ -315,7 +315,8 @@ impl World {
 
             load_entities_from_dir(&region_path.join("npcs"), &region_name, &mut |id, content| {
                 let nf: NpcFile = toml::from_str(content).map_err(|e| format!("Bad npc {id}: {e}"))?;
-                let combat = nf.combat.map(|c| NpcCombatStats { max_hp: c.max_hp, attack: c.attack, defense: c.defense, xp_reward: c.xp_reward });
+                let combat = Some(nf.combat.map(|c| NpcCombatStats { max_hp: c.max_hp, attack: c.attack, defense: c.defense, xp_reward: c.xp_reward })
+                    .unwrap_or(NpcCombatStats { max_hp: 20, attack: 4, defense: 2, xp_reward: 5 }));
                 let greeting = nf.dialogue.and_then(|d| d.greeting);
                 npcs.insert(id.clone(), Npc { id: id.clone(), name: nf.name, description: nf.description, room: nf.room, base_attitude: nf.base_attitude, faction: nf.faction, respawn_secs: nf.respawn_secs, greeting, combat });
                 Ok(())