/**
 * Copyright (c) 2025-2026, Michael Yang 杨福海 (fuhai999@gmail.com).
 * <p>
 * Licensed under the GNU Lesser General Public License (LGPL) ,Version 3.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * <p>
 * http://www.gnu.org/licenses/lgpl-3.0.txt
 * <p>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.easyagents.flow.core.code;

import com.easyagents.flow.core.code.impl.JavascriptRuntimeEngine;

import java.util.ArrayList;
import java.util.List;

/**
 * 管理代码节点运行时引擎提供者。
 */
public class CodeRuntimeEngineManager {

    public List<CodeRuntimeEngineProvider> providers = new ArrayList<>();
    /**
     * JavaScript 引擎实例，可在业务启动阶段配置超时后替换。
     */
    private volatile JavascriptRuntimeEngine javascriptRuntimeEngine;

    private static class ManagerHolder {
        private static final CodeRuntimeEngineManager INSTANCE = new CodeRuntimeEngineManager();
    }

    private CodeRuntimeEngineManager() {
        javascriptRuntimeEngine = new JavascriptRuntimeEngine();
        providers.add(engineId -> {
            if ("js".equals(engineId) || "javascript".equals(engineId)) {
                return javascriptRuntimeEngine;
            }
            return null;
        });
    }

    /**
     * 获取全局代码运行时管理器。
     *
     * @return 代码运行时管理器
     */
    public static CodeRuntimeEngineManager getInstance() {
        return ManagerHolder.INSTANCE;
    }

    /**
     * 配置 JavaScript 代码执行超时。
     *
     * @param timeoutMs 超时时间；0 表示关闭超时
     * @throws IllegalArgumentException 超时时间为负数时抛出
     */
    public void configureJavascriptRuntimeEngine(long timeoutMs) {
        javascriptRuntimeEngine =
                new JavascriptRuntimeEngine(timeoutMs);
    }

    /**
     * 注册代码运行时提供者。
     *
     * @param provider 代码运行时提供者
     */
    public void registerProvider(CodeRuntimeEngineProvider provider) {
        providers.add(provider);
    }

    /**
     * 移除代码运行时提供者。
     *
     * @param provider 代码运行时提供者
     */
    public void removeProvider(CodeRuntimeEngineProvider provider) {
        providers.remove(provider);
    }

    /**
     * 按引擎标识获取代码运行时。
     *
     * @param engineId 引擎标识
     * @return 匹配的代码运行时；未找到时返回 {@code null}
     */
    public CodeRuntimeEngine getCodeRuntimeEngine(Object engineId) {
        for (CodeRuntimeEngineProvider provider : providers) {
            CodeRuntimeEngine codeRuntimeEngine = provider.getCodeRuntimeEngine(engineId);
            if (codeRuntimeEngine != null) {
                return codeRuntimeEngine;
            }
        }
        return null;
    }
}
