boardgame-core/src/core/rule.ts

import {Context} from "./context";
import {Command} from "../utils/command";
import {effect} from "@preact/signals-core";

export type RuleContext<T> = Context & {
    actions: Command[];
    handledActions: number;
    invocations: RuleContext<unknown>[];
    resolution?: T;
}

/**
 * 调用规则生成器并管理其上下文
 * @param pushContext - 用于推送上下文到上下文栈的函数
 * @param type - 规则类型
 * @param rule - 规则生成器函数
 * @returns 规则执行结果
 */
export function invokeRuleContext<T>(
    pushContext: (context: Context) => void, 
    type: string, 
    rule: Generator<string, T, Command>
): RuleContext<T> {
    const ctx: RuleContext<T> = {
        type,
        actions: [],
        handledActions: 0,
        invocations: [],
        resolution: undefined,
    };

    // 执行生成器直到完成或需要等待动作
    const executeRule = () => {
        try {
            const result = rule.next();
            
            if (result.done) {
                // 规则执行完成，设置结果
                ctx.resolution = result.value;
                return;
            }

            // 如果生成器 yield 了一个动作类型，等待处理
            // 这里可以扩展为实际的动作处理逻辑
            const actionType = result.value;
            
            // 继续执行直到有动作需要处理或规则完成
            if (!result.done) {
                executeRule();
            }
        } catch (error) {
            // 规则执行出错，抛出错误
            throw error;
        }
    };

    // 使用 effect 来跟踪响应式依赖
    const dispose = effect(() => {
        if (ctx.resolution !== undefined) {
            dispose();
            return;
        }
        executeRule();
    });

    // 将规则上下文推入栈中
    pushContext(ctx);

    return ctx;
}

/**
 * 创建一个规则生成器辅助函数
 * @param type - 规则类型
 * @param fn - 规则逻辑函数
 */
export function createRule<T>(
    type: string,
    fn: (ctx: RuleContext<T>) => Generator<string, T, Command>
): Generator<string, T, Command> {
    return fn({
        type,
        actions: [],
        handledActions: 0,
        invocations: [],
        resolution: undefined,
    });
}