path: root/WORLDBUILDING.md

# World Building Guide

Third Collapse is data-driven. Everything — rooms, items, mobs, objects, behaviors — is defined in YAML files under `data/`. No code changes needed to build a world.

## Quick Reference

| What you want | Where to put it |
|---|---|
| A room | `data/rooms/<id>.yaml` |
| An item (sword, ore, key) | `data/items/<id>.yaml` |
| A mob (NPC, monster) | `data/mobs/<id>.yaml` |
| An interactive object (rock, lever, door) | `data/objects/<id>.yaml` |
| A behavior (mining, dialog, toggle) | `data/behaviors/<id>.yaml` |
| A shared drop table | `data/drops/<id>.yaml` |

## State: World vs Player

**World flags** (`set_flags`, checked with `flag`) are shared by every player on the server. A door opened by one player is open for everyone. A lever pulled once changes the world for all.

**Player flags** (`set_player_flags`, checked with `player_flag`) are per-character. Quest progress, "has read the sign," "paid the toll" — these are different for each player. Saved to the character YAML and persist across logins.

---

## Rooms

Minimal room:
```yaml
id: 1
name: "Town Square"
description: "Cobblestone paths lead in all directions. A fountain gurgles peacefully."
exits:
  north: 2
  west: 7
  east: 3
```

### Exits — simple vs conditional

Simple exit — always passable:
```yaml
exits:
  north: 2
```

Conditional exit — blocked until a world flag is set:
```yaml
exits:
  north:
    room: 11
    condition:
      flag: gate_open
      value: true
    blocked_message: "A heavy iron gate blocks the way north."
```

Conditional exit — blocked unless the PLAYER has a flag (key, permission, quest state):
```yaml
exits:
  east:
    room: 12
    condition:
      player_flag: has_vault_key
      value: true
    blocked_message: "The vault door is locked. You need a key."
```

Conditional exit with compound condition — requires both a world flag AND a player flag:
```yaml
exits:
  north:
    room: 20
    condition:
      all_of:
        - flag: bridge_repaired
          value: true
        - player_flag: paid_toll
          value: true
    blocked_message: "The bridge is out, and the toll collector blocks the path."
```

### Spawns — ground items that respawn

```yaml
spawns:
  - item_id: bronze_pickaxe
    quantity: 1
    respawn_ticks: 30     # reappears 30 ticks (18 seconds) after being picked up
  - item_id: copper_ore
    quantity: 3
    respawn_ticks: 50
```

### Mobs — NPCs placed in the room

```yaml
mobs:
  - "man"           # spawns a "man" mob
  - "man"           # second "man" — duplicate IDs create multiple instances
  - "guard"         # unique named mob
```

### Objects — interactive fixtures

```yaml
objects:
  - id: copper_rock                                    # simple placement
  - id: copper_rock                                    # second instance
  - id: fishing_spot
    wander_rooms: [7, 8, 9]                            # moves between these rooms
    wander_interval: 12                                # every 12 ticks
  - id: iron_gate                                      # hidden object (see below)
```

### On-enter scripts — messages when a player arrives

```yaml
on_enter:
  - message: "The guard barks: \"State your business!\""
    condition:
      player_flag: talked_to_guard
      not: true                                        # only first visit

  - message: "The guard nods. \"Back again?\""
    condition:
      player_flag: talked_to_guard
      value: true                                      # subsequent visits
```

---

## Items

```yaml
id: bronze_pickaxe
name: bronze pickaxe
aliases: ["pick", "pickaxe"]
description: "A sturdy bronze pickaxe."
value: 10
stackable: false
equip_slot: main_hand        # optional — where it equips
weapon_type: melee            # optional — melee or ranged
stats:                        # optional — combat bonuses
  attack_bonus: 2
  strength_bonus: 1
speed: 5                      # ticks between attacks
toolbelt: true                # usable from toolbelt (doesn't need to be in inventory)
tool_type: pickaxe            # used by gather behaviors that require "tool: pickaxe"
tool_speed: 2                 # reduces gather wait time
```

Key item (quest token, not equippable):
```yaml
id: pass_stub
name: pass stub
description: "A crumpled slip of paper stamped with the guard's seal."
value: 0
stackable: false
```

---

## Mobs

Basic combat mob:
```yaml
id: "man"
name: "man"
description: "A shabby-looking man."
attack: 1
strength: 1
defense: 1
hp: 7
speed: 5
aggressive: false
respawn_ticks: 30
wander_rooms: [1, 2, 3]
wander_interval: 10
drops:
  remains: "bones"             # always dropped on death
  loot:
    - item_id: "credits"
      weight: 98
      quantity: 10
    - item_id: "credits"
      weight: 2
      quantity: 150
idle_descriptions:
  - "scribbles something in a small notebook"
  - "gazes skyward at the clouds"
combat_descriptions:
  - "is engaged in a fight to the death with %s"
```

Mob with a behavior — can be talked to, toggled, etc:
```yaml
id: "guard"
name: "Guard"
behavior: guard_talk          # links to data/behaviors/guard_talk.yaml
unique: true                  # displays as "Guard" not "a guard"
protected: true               # cannot be attacked
attack: 5
strength: 5
defense: 5
hp: 30
speed: 5
aggressive: false
respawn_ticks: 60
idle_descriptions:
  - "scans the area with a watchful eye"
  - "adjusts the grip on his weapon"
```

---

## Objects

Object defined — links to a behavior:
```yaml
id: copper_rock
name: copper rock
behavior: mine_copper
```

Hidden object — doesn't appear in room's object list, only discoverable via description or experimentation:
```yaml
id: iron_gate
name: iron gate
behavior: iron_gate_toggle
hidden: true
props:
  description: "A heavy iron gate set into the north wall."
```

Decorative object (no behavior):
```yaml
id: lumby_fountain
name: town fountain
behavior: ""
props:
  description: "Clear water sparkles in the sunlight."
```

---

## Behaviors

### Gather (mining, fishing, woodcutting)

```yaml
id: mine_copper
type: gather
skill: mining
level: 1
base_wait: 8                   # ticks between attempts
tool: pickaxe                  # requires item with tool_type: pickaxe
success:
  base: 0.40                   # 40% base chance
  per_level: 0.01              # +1% per level above requirement
  cap: 0.95                    # 95% max
gather_message: "You swing your pickaxe at the rock..."
fail_message: "You chip away but get nothing useful."
drops:
  - item_id: copper_ore
    weight: 90                 # 90% chance when roll succeeds
    depletes: true             # rock becomes depleted after this drop
    message: "You manage to mine some copper ore."
  - table: gem_table           # reference a shared drop table
    weight: 10
    depletes: false            # gem drops don't deplete the rock
    message: "You spot a glint of something valuable!"
deplete_delay: 50              # ticks until rock respawns
respawn_message: "You see more ore in the rock."
respawn_broadcast: "A glint of copper catches your eye from some {name}."
```

Non-depleting gather (fishing):
```yaml
id: fish_trout
type: gather
skill: fishing
level: 1
base_wait: 4
tool: fishing_rod
success:
  base: 0.30
  per_level: 0.01
  cap: 0.90
gather_message: "You cast your line into the water..."
fail_message: "Nothing seems to bite."
drops:
  - item_id: raw_trout
    weight: 100
    depletes: false            # never depletes
    message: "You catch a trout!"
```

### Talk (dialog trees)

Full conversation with conditions, actions, and player flag tracking:
```yaml
id: guard_talk
type: talk
nodes:
  start:
    message: "\"Halt! This area is restricted.\""
    options:
      - text: "\"What's behind that gate?\""
        goto: about_gate
      - text: "\"I have copper ore.\""            # only shows if player has ore
        goto: trade_ore
        condition:
          has_item: copper_ore
      - text: "\"I have a pass.\""                # only shows if player earned a pass
        goto: has_pass
        condition:
          player_flag: got_pass
          value: true
      - text: "\"Goodbye.\""
        end: true

  about_gate:
    message: "\"Bring me some copper ore and I'll stamp you a pass.\""
    action:
      set_player_flags:                           # player-local: only this player
        talked_to_guard: true
    options:
      - text: "\"I'll be back.\""
        end: true
      - text: "\"I have some right here.\""
        goto: trade_ore
        condition:
          has_item: copper_ore

  trade_ore:
    message: "\"Good quality ore.\" He stamps a pass and hands it to you."
    action:
      take_item: copper_ore                       # removes 1 copper ore
      give_item: pass_stub                        # gives pass stub
      set_player_flags:
        got_pass: true                            # player now "has a pass"
    options:
      - text: "\"Thanks.\""
        end: true

  has_pass:
    message: "\"Alright, I'll open the gate for you.\""
    action:
      set_flags:                                  # WORLD flag: gate opens for everyone
        gate_open: true
    options:
      - text: "\"Thanks.\""
        end: true
```

#### Node action reference

| Field | Effect |
|---|---|
| `set_flags` | Sets world flags (global, shared by all players) |
| `set_player_flags` | Sets player-local flags (per-character, quest progress) |
| `give_item` | Gives an item to the player's inventory |
| `take_item` | Removes an item from the player's inventory |
| `teleport` | Moves the player to a room ID |
| `heal` | Restores that many hitpoints |

All fields in a single action are processed together — you can give an item, take an item, set flags, and heal all in one node.

Example — quest completion:
```yaml
action:
  take_item: dragon_head
  give_item: dragon_slayer_medal
  set_player_flags:
    dragon_quest: complete
    dragon_slain: true
  heal: 99
  teleport: 1                                     # return to town
```

### Toggle (levers, switches, gates)

Simple toggle that sets a world flag:
```yaml
id: iron_gate_toggle
type: toggle
message: "You push the heavy iron gate open."
set_flags:
  gate_open: true
check:                                            # only works when gate is closed
  flag: gate_open
  value: true
  not: true
```

Lever that toggles between two states:
```yaml
id: bridge_lever
type: toggle
message: "You pull the lever. Mechanisms groan somewhere in the distance."
set_flags:
  bridge_extended: true
check:
  flag: bridge_extended
  value: true
  not: true
```

### Use (crafting stations)

```yaml
id: smelt_copper
type: use
message: "You place the ore in the furnace..."
wait: 4                          # ticks between crafts
consume:                         # items consumed per craft
  copper_ore: 1
reward:                          # item produced
  item_id: copper_bar
  quantity: 1
fail_message: "The ore crumbles to dust."
success:
  base: 0.60
  per_level: 0.01
  cap: 0.95
skill: smithing
level: 1
```

---

## Conditions Reference

Conditions are used in talk options, exit gates, on-enter scripts, and toggle checks.

### Simple conditions

```yaml
# Check a world flag
condition:
  flag: gate_open
  value: true

# Check a world flag is NOT set
condition:
  flag: gate_open
  not: true

# Check a player flag
condition:
  player_flag: finished_tutorial
  value: true

# Check if player has an item
condition:
  has_item: bronze_key

# Check if player does NOT have an item
condition:
  has_item: bronze_key
  not: true
```

### Compound conditions

All must pass:
```yaml
condition:
  all_of:
    - flag: gate_open
      value: true
    - has_item: pass_stub
```

Any one must pass:
```yaml
condition:
  any_of:
    - has_item: bronze_key
    - has_item: iron_key
    - player_flag: master_of_unlocking
      value: true
```

Nested compounds:
```yaml
condition:
  all_of:
    - player_flag: quest_started
      value: true
    - any_of:
        - has_item: wolf_pelt
        - has_item: bear_pelt
```

---

## Drop Tables

Shared drop tables can be referenced by multiple behaviors:
```yaml
# data/drops/gem_table.yaml
id: gem_table
drops:
  - item_id: uncut_sapphire
    weight: 47
  - item_id: uncut_emerald
    weight: 16
  - item_id: uncut_ruby
    weight: 4
  - item_id: uncut_diamond
    weight: 1
```

Referenced from a gather behavior:
```yaml
drops:
  - item_id: copper_ore
    weight: 90
    depletes: true
  - table: gem_table          # pulls from data/drops/gem_table.yaml
    weight: 10
    depletes: false
```

---

## Global vs Player State: Door Examples

### Example A: Door with a button in another room (GLOBAL)

A button in room 3 opens a door in room 7. Anyone can press it. Once pressed, the door is open for everyone.

**Button object** (`data/objects/door_button.yaml`):
```yaml
id: door_button
name: stone button
behavior: button_toggle
hidden: true
```

**Button behavior** (`data/behaviors/button_toggle.yaml`):
```yaml
id: button_toggle
type: toggle
message: "You press the stone button. You hear grinding stone in the distance."
set_flags:
  secret_door_open: true                               # WORLD flag
check:
  flag: secret_door_open
  not: true                                            # only works when door is closed
```

**Room 3** — contains the button:
```yaml
id: 3
name: "Button Chamber"
description: "A small stone chamber. A button protrudes from the east wall."
exits:
  south: 1
objects:
  - id: door_button
```

**Room 7** — contains the door:
```yaml
id: 7
name: "Hidden Passage"
description: "A dusty corridor. A heavy stone door blocks the way north."
exits:
  south: 2
  north:
    room: 8
    condition:
      flag: secret_door_open                           # checks WORLD flag
      value: true
    blocked_message: "A heavy stone door blocks the way."
objects:
  - id: stone_door
    hidden: true
```

### Example B: Key-locked door (PLAYER-LOCAL)

A locked door that only opens for a player carrying the key. Each player must find their own key.

**Key item** (`data/items/rusty_key.yaml`):
```yaml
id: rusty_key
name: rusty key
description: "An old iron key, still functional."
value: 0
stackable: false
```

**Room 5** — locked door:
```yaml
id: 5
name: "Locked Storage"
description: "A small storage room. The way east is blocked by a locked iron door."
exits:
  west: 2
  east:
    room: 6
    condition:
      has_item: rusty_key                               # checks PLAYER inventory
    blocked_message: "The iron door is locked. You need a key."
objects:
  - id: iron_door
    hidden: true
```

**Room 6** — the other side (no key needed to exit):
```yaml
id: 6
name: "Storage Closet"
description: "Shelves of dusty crates."
exits:
  west: 5                                               # exit back — no condition
spawns:
  - item_id: uncut_ruby
    quantity: 1
    respawn_ticks: 500
```

Key difference: the button door uses `flag` (shared state — one player presses, everyone benefits), the key door uses `has_item` (per-player inventory check — each player needs their own key).

---

## Complete Quest Example: "Clear the Rats"

### 1. Quest giver mob (`data/mobs/quest_giver.yaml`)
```yaml
id: "quest_giver"
name: "Elder"
behavior: rat_quest_talk
unique: true
protected: true
attack: 1
strength: 1
defense: 1
hp: 20
speed: 5
aggressive: false
idle_descriptions:
  - "mutters about the rat infestation"
```

### 2. Dialog behavior (`data/behaviors/rat_quest_talk.yaml`)
```yaml
id: rat_quest_talk
type: talk
nodes:
  start:
    message: "\"Rats! Rats everywhere in the cellar. Clear them out and I'll reward you.\""
    options:
      - text: "\"I'll handle it.\""
        goto: accept_quest
        condition:
          player_flag: rat_quest
          not: true
      - text: "\"I killed the rats.\""
        goto: turn_in
        condition:
          player_flag: rat_quest
          value: started
      - text: "\"Goodbye.\""
        end: true

  accept_quest:
    message: "\"Good lad. The cellar is west of here. Come back when they're dead.\""
    action:
      set_player_flags:
        rat_quest: started
    options:
      - text: "\"On my way.\""
        end: true

  turn_in:
    message: "\"You did it! The village owes you a debt. Here — take this.\""
    action:
      give_item: rusty_sword
      set_player_flags:
        rat_quest: complete
      heal: 10
    options:
      - text: "\"Thanks!\""
        end: true
```

### 3. Rat mobs (`data/mobs/rat.yaml`)
```yaml
id: "rat"
name: "giant rat"
attack: 2
strength: 1
defense: 1
hp: 3
speed: 4
aggressive: true
respawn_ticks: 60
drops:
  remains: "rat bones"
```

### 4. Cellar room (`data/rooms/20.yaml`)
```yaml
id: 20
name: "Cellar"
description: "A damp, dark cellar. The floor scuttles with movement."
exits:
  east: 1
mobs:
  - "rat"
  - "rat"
  - "rat"
  - "rat"
  - "rat"
```

### 5. Room 1 with quest giver (`data/rooms/1.yaml`)
```yaml
id: 1
name: "Town Square"
description: "Cobblestone paths lead in all directions. The Elder stands near the fountain."
exits:
  west: 20
  north: 2
mobs:
  - "quest_giver"
objects:
  - id: lumby_fountain
```

---

## Wandering Objects

Fishing spots that move between rooms:
```yaml
# data/objects/fishing_spot.yaml
id: fishing_spot
name: fishing spot
behavior: fish_trout
```

```yaml
# In rooms 7, 8, and 9:
objects:
  - id: fishing_spot
    wander_rooms: [7, 8, 9]
    wander_interval: 12
```

Players gathering from a wandering object are silently interrupted when it moves.

---

## Wandering Mobs

```yaml
# mobs that roam between rooms:
wander_rooms: [1, 2, 3, 4]
wander_interval: 10     # moves every 10 ticks
```

Mobs stop wandering while in combat. Dead mobs respawn at their home room after `respawn_ticks`.

---

## Hidden Objects

Objects with `hidden: true` don't appear in the room's object listing. Players discover them by reading room descriptions or trying commands. The object is still fully interactable — `push gate`, `look gate`, etc.

```yaml
# data/objects/secret_lever.yaml
id: secret_lever
name: stone lever
behavior: secret_toggle
hidden: true
props:
  description: "A cleverly concealed lever behind a loose stone."
```

Room description hints at it:
```yaml
description: "A dusty corridor. One of the wall stones looks slightly out of place."
```

---

## Tips

1. **Use player flags for quest progress, world flags for environmental state.** If a bridge is repaired, that's world state. If a player has read a sign, that's player state.

2. **Conditions on enter scripts** make rooms feel alive. A guard who only barks the first time, a room that changes after a quest completes.

3. **Hidden objects** keep room descriptions clean. Mention them in the room's description text instead of auto-listing them.

4. **Drop tables** are shareable. The `gem_table` is used by copper rocks AND mob loot. Define once, reference everywhere.

5. **Objects are for fixtures, mobs are for living things.** If it has HP and can die, it's a mob. If it's a rock, lever, door, or crafting station, it's an object. Both can have behaviors.

6. **The `behavior` field on mobs** lets you talk to them directly — `talk guard` finds the guard mob, no duplicate object entry needed.

7. **Exits accept both `int` and `map` formats.** `north: 2` is shorthand for `north: {room: 2}`. Add `condition` and `blocked_message` only when needed.

8. **Live editing works.** Room, item, mob, object, and behavior YAML files are read from disk on each access. Change a room description or dialog and it takes effect immediately — no restart needed.