Source code for evennia.contrib.tutorials.evadventure.combat_base

EvAdventure Base combat utilities.

This establishes the basic building blocks for combat:

- `CombatFailure` - exception for combat-specific errors.
- `CombatAction` (and subclasses) - classes encompassing all the working around an action.
  They are initialized from 'action-dicts` - dictionaries with all the relevant data for the
  particular invocation
- `CombatHandler` - base class for running a combat. Exactly how this is used depends on the
  type of combat intended (twitch- or turn-based) so many details of this will be implemented
  in child classes.



from evennia.scripts.scripts import DefaultScript
from evennia.typeclasses.attributes import AttributeProperty
from evennia.utils import evtable
from evennia.utils.create import create_script

from . import rules

[docs]class CombatFailure(RuntimeError): """ Some failure during combat actions. """
[docs]class CombatAction: """ Parent class for all actions. This represents the executable code to run to perform an action. It is initialized from an 'action-dict', a set of properties stored in the action queue by each combatant. """
[docs] def __init__(self, combathandler, combatant, action_dict): """ Each key-value pair in the action-dict is stored as a property on this class for later access. Args: combatant (EvAdventureCharacter, EvAdventureNPC): The combatant performing the action. action_dict (dict): A dict containing all properties to initialize on this class. This should not be any keys with `_` prefix, since these are used internally by the class. """ self.combathandler = combathandler self.combatant = combatant # store the action dicts' keys as properties accessible as e.g. etc for key, val in action_dict.items(): if not key.startswith("_"): setattr(self, key, val)
[docs] def msg(self, message, broadcast=True): """ Convenience route to the combathandler msg-sender mechanism. Args: message (str): Message to send; use `$You()` and `$You(other.key)` to refer to the combatant doing the action and other combatants, respectively. """ self.combathandler.msg(message, combatant=self.combatant, broadcast=broadcast)
[docs] def can_use(self): """ Called to determine if the action is usable with the current settings. This does not actually perform the action. Returns: bool: If this action can be used at this time. """ return True
[docs] def execute(self): """ Perform the action as the combatant. Should normally make use of the properties stored on the class during initialization. """ pass
[docs] def post_execute(self): """ Called after execution. """ pass
[docs]class CombatActionHold(CombatAction): """ Action that does nothing. :: action_dict = { "key": "hold" } """
[docs]class CombatActionAttack(CombatAction): """ A regular attack, using a wielded weapon. :: action-dict = { "key": "attack", "target": Character/Object } """
[docs] def execute(self): attacker = self.combatant weapon = attacker.weapon target = if weapon.at_pre_use(attacker, target): weapon.use( attacker, target, advantage=self.combathandler.has_advantage(attacker, target) ) weapon.at_post_use(attacker, target)
[docs]class CombatActionStunt(CombatAction): """ Perform a stunt the grants a beneficiary (can be self) advantage on their next action against a target. Whenever performing a stunt that would affect another negatively (giving them disadvantage against an ally, or granting an advantage against them, we need to make a check first. We don't do a check if giving an advantage to an ally or ourselves. :: action_dict = { "key": "stunt", "recipient": Character/NPC, "target": Character/NPC, "advantage": bool, # if False, it's a disadvantage "stunt_type": Ability, # what ability (like STR, DEX etc) to use to perform this stunt. "defense_type": Ability, # what ability to use to defend against (negative) effects of this stunt. } """
[docs] def execute(self): combathandler = self.combathandler attacker = self.combatant recipient = self.recipient # the one to receive the effect of the stunt target = # the affected by the stunt (can be the same as recipient/combatant) txt = "" if recipient == target: # grant another entity dis/advantage against themselves defender = recipient else: # recipient not same as target; who will defend depends on disadvantage or advantage # to give. defender = target if self.advantage else recipient # trying to give advantage to recipient against target. Target defends against caller is_success, _, txt = rules.dice.opposed_saving_throw( attacker, defender, attack_type=self.stunt_type, defense_type=self.defense_type, advantage=combathandler.has_advantage(attacker, defender), disadvantage=combathandler.has_disadvantage(attacker, defender), ) self.msg(f"$You() $conj(attempt) stunt on $You({defender.key}). {txt}") # deal with results if is_success: if self.advantage: combathandler.give_advantage(recipient, target) else: combathandler.give_disadvantage(recipient, target) if recipient == self.combatant: self.msg( f"$You() $conj(gain) {'advantage' if self.advantage else 'disadvantage'} " f"against $You({target.key})!" ) else: self.msg( f"$You() $conj(cause) $You({recipient.key}) " f"to gain {'advantage' if self.advantage else 'disadvantage'} " f"against $You({target.key})!" ) else: self.msg(f"$You({defender.key}) $conj(resist)! $You() $conj(fail) the stunt.")
[docs]class CombatActionUseItem(CombatAction): """ Use an item in combat. This is meant for one-off or limited-use items (so things like scrolls and potions, not swords and shields). If this is some sort of weapon or spell rune, we refer to the item to determine what to use for attack/defense rolls. :: action_dict = { "key": "use", "item": Object "target": Character/NPC/Object/None } """
[docs] def execute(self): item = self.item user = self.combatant target = if item.at_pre_use(user, target): item.use( user, target, advantage=self.combathandler.has_advantage(user, target), disadvantage=self.combathandler.has_disadvantage(user, target), ) item.at_post_use(user, target)
[docs]class CombatActionWield(CombatAction): """ Wield a new weapon (or spell) from your inventory. This will swap out the one you are currently wielding, if any. :: action_dict = { "key": "wield", "item": Object } """
[docs] def execute(self): self.msg(f"$You() $conj(wield) $You({self.item.key}).")
# main combathandler
[docs]class EvAdventureCombatBaseHandler(DefaultScript): """ This script is created when a combat starts. It 'ticks' the combat and tracks all sides of it. """ # available actions in combat action_classes = { "hold": CombatActionHold, "attack": CombatActionAttack, "stunt": CombatActionStunt, "use": CombatActionUseItem, "wield": CombatActionWield, } # fallback action if not selecting anything fallback_action_dict = AttributeProperty({"key": "hold"}, autocreate=False)
[docs] @classmethod def get_or_create_combathandler(cls, obj, **kwargs): """ Get or create a combathandler on `obj`. Args: obj (any): The Typeclassed entity to store the CombatHandler Script on. This could be a location (for turn-based combat) or a Character (for twitch-based combat). Keyword Args: combathandler_key (str): They key name for the script. Will be 'combathandler' by default. **kwargs: Arguments to the Script, if it is created. """ if not obj: raise CombatFailure("Cannot start combat without a place to do it!") combathandler_key = kwargs.pop("key", "combathandler") combathandler = obj.ndb.combathandler if not combathandler or not combathandler = obj.scripts.get(combathandler_key).first() if not combathandler: # have to create from scratch persistent = kwargs.pop("persistent", True) combathandler = create_script( cls, key=combathandler_key, obj=obj, persistent=persistent, autostart=False, **kwargs, ) obj.ndb.combathandler = combathandler return combathandler
[docs] def msg(self, message, combatant=None, broadcast=True, location=None): """ Central place for sending messages to combatants. This allows for adding any combat-specific text-decoration in one place. Args: message (str): The message to send. combatant (Object): The 'You' in the message, if any. broadcast (bool): If `False`, `combatant` must be included and will be the only one to see the message. If `True`, send to everyone in the location. location (Object, optional): If given, use this as the location to send broadcast messages to. If not, use `self.obj` as that location. Notes: If `combatant` is given, use `$You/you()` markup to create a message that looks different depending on who sees it. Use `$You(combatant_key)` to refer to other combatants. """ if not location: location = self.obj location_objs = location.contents exclude = [] if not broadcast and combatant: exclude = [obj for obj in location_objs if obj is not combatant] location.msg_contents( message, exclude=exclude, from_obj=combatant, mapping={locobj.key: locobj for locobj in location_objs}, )
[docs] def get_combat_summary(self, combatant): """ Get a 'battle report' - an overview of the current state of combat from the perspective of one of the sides. Args: combatant (EvAdventureCharacter, EvAdventureNPC): The combatant to get. Returns: EvTable: A table representing the current state of combat. Example: :: Goblin shaman (Perfect) Gregor (Hurt) Goblin brawler(Hurt) Bob (Perfect) vs Goblin grunt 1 (Hurt) Goblin grunt 2 (Perfect) Goblin grunt 3 (Wounded) """ allies, enemies = self.get_sides(combatant) nallies, nenemies = len(allies), len(enemies) # prepare colors and hurt-levels allies = [f"{ally} ({ally.hurt_level})" for ally in allies] enemies = [f"{enemy} ({enemy.hurt_level})" for enemy in enemies] # the center column with the 'vs' vs_column = ["" for _ in range(max(nallies, nenemies))] vs_column[len(vs_column) // 2] = "|wvs|n" # the two allies / enemies columns should be centered vertically diff = abs(nallies - nenemies) top_empty = diff // 2 bot_empty = diff - top_empty topfill = ["" for _ in range(top_empty)] botfill = ["" for _ in range(bot_empty)] if nallies >= nenemies: enemies = topfill + enemies + botfill else: allies = topfill + allies + botfill # make a table with three columns return evtable.EvTable( table=[ evtable.EvColumn(*allies, align="l"), evtable.EvColumn(*vs_column, align="c"), evtable.EvColumn(*enemies, align="r"), ], border=None, maxwidth=78, )
[docs] def get_sides(self, combatant): """ Get a listing of the two 'sides' of this combat, from the perspective of the provided combatant. The sides don't need to be balanced. Args: combatant (Character or NPC): The one whose sides are to determined. Returns: tuple: A tuple of lists `(allies, enemies)`, from the perspective of `combatant`. Note: The sides are found by checking PCs vs NPCs. PCs can normally not attack other PCs, so are naturally allies. If the current room has the `allow_pvp` Attribute set, then _all_ other combatants (PCs and NPCs alike) are considered valid enemies (one could expand this with group mechanics). """ raise NotImplementedError
[docs] def give_advantage(self, recipient, target): """ Let a benefiter gain advantage against the target. Args: recipient (Character or NPC): The one to gain the advantage. This may or may not be the same entity that creates the advantage in the first place. target (Character or NPC): The one against which the target gains advantage. This could (in principle) be the same as the benefiter (e.g. gaining advantage on some future boost) """ raise NotImplementedError
[docs] def give_disadvantage(self, recipient, target): """ Let an affected party gain disadvantage against a target. Args: recipient (Character or NPC): The one to get the disadvantage. target (Character or NPC): The one against which the target gains disadvantage, usually an enemy. """ raise NotImplementedError
[docs] def has_advantage(self, combatant, target): """ Check if a given combatant has advantage against a target. Args: combatant (Character or NPC): The one to check if they have advantage target (Character or NPC): The target to check advantage against. """ raise NotImplementedError
[docs] def has_disadvantage(self, combatant, target): """ Check if a given combatant has disadvantage against a target. Args: combatant (Character or NPC): The one to check if they have disadvantage target (Character or NPC): The target to check disadvantage against. """ raise NotImplementedError
[docs] def queue_action(self, action_dict, combatant=None): """ Queue an action by adding the new actiondict. Args: action_dict (dict): A dict describing the action class by name along with properties. combatant (EvAdventureCharacter, EvAdventureNPC, optional): A combatant queueing the action. """ raise NotImplementedError
[docs] def execute_next_action(self, combatant): """ Perform a combatant's next action. Args: combatant (EvAdventureCharacter, EvAdventureNPC): The combatant performing and action. """ raise NotImplementedError
[docs] def start_combat(self): """ Start combat. """ raise NotImplementedError
[docs] def check_stop_combat(self): """ Check if this combat should be aborted, whatever this means for the particular the particular combat type. Keyword Args: kwargs: Any extra keyword args used. Returns: bool: If `True`, the `stop_combat` method should be called. """ raise NotImplementedError
[docs] def stop_combat(self): """ Stop combat. This should also do all cleanup. """ raise NotImplementedError