CharacterGardenStack/charactergarden/app/src/world/applyActions.ts

import { randomUUID } from "node:crypto";

import type { Action } from "../contracts/action";
import type { ValidationResult } from "../contracts/validation";
import type { Entity } from "../contracts/entity";
import type { WorldState } from "../contracts/world";

function cloneWorldState(worldState: WorldState): WorldState {
  const entities: Record<string, Entity> = {};
  for (const [id, entity] of Object.entries(worldState.entities)) {
    entities[id] = {
      ...entity,
      attributes: { ...entity.attributes },
    };
  }

  return {
    ...worldState,
    entities,
    metadata: { ...worldState.metadata },
  };
}

export function applyActions(
  actions: Action[],
  results: ValidationResult[],
  worldState: WorldState
): WorldState {
  const nextState = cloneWorldState(worldState);

  for (const result of results) {
    if (!result.success) {
      continue;
    }

    const action = actions[result.actionIndex];
    if (!action) {
      continue;
    }

    const actor = nextState.entities[action.actorId];
    const target = action.targetId ? nextState.entities[action.targetId] : undefined;

    switch (action.type) {
      case "move":
        if (actor && action.targetId) {
          actor.attributes.location = action.targetId;
        }
        break;
      case "take":
        if (actor && target) {
          target.attributes.location = `inventory:${actor.id}`;
          if (target.id === "key_1") {
            actor.attributes.has_key_1 = true;
          }
        }
        break;
      case "open":
        if (target) {
          target.attributes.open = true;
        }
        break;
      case "inspect":
      default:
        break;
    }
  }

  nextState.id = randomUUID();
  nextState.createdAt = Date.now();

  return nextState;
}