import type { RunResult } from "../types";
import { getRunnerStrategy } from "../config/runnerStrategies";

/**
 * 代码运行引擎
 * 使用策略模式支持多种语言
 */
export class CodeRunner {
  private timeout: number;
  private abortController: AbortController | null = null;

  constructor(timeout: number = 5000) {
    this.timeout = timeout;
  }

  /**
   * 运行代码
   */
  async run(
    code: string,
    language: string,
    testCases?: import("../types").TestCase[],
  ): Promise<RunResult> {
    // 获取对应语言的运行策略
    const strategy = getRunnerStrategy(language);

    if (!strategy) {
      return {
        output: "",
        error: `语言 "${language}" 不支持运行`,
        executionTime: 0,
        status: "error",
      };
    }

    // 创建超时控制
    this.abortController = new AbortController();
    const timeoutId = setTimeout(() => {
      this.abortController?.abort();
    }, this.timeout);

    try {
      // 执行代码
      const result = await Promise.race([
        strategy(code, testCases),
        this.createTimeoutPromise(),
      ]);

      clearTimeout(timeoutId);
      return result;
    } catch (error: any) {
      clearTimeout(timeoutId);

      if (error.name === "AbortError") {
        return {
          output: "",
          error: `执行超时（${this.timeout}ms）`,
          executionTime: this.timeout,
          status: "timeout",
        };
      }

      return {
        output: "",
        error: error.message || String(error),
        executionTime: 0,
        status: "error",
      };
    } finally {
      this.abortController = null;
    }
  }

  /**
   * 创建超时 Promise
   */
  private createTimeoutPromise(): Promise<RunResult> {
    return new Promise((_, reject) => {
      this.abortController?.signal.addEventListener("abort", () => {
        const error = new Error("Execution timeout");
        error.name = "AbortError";
        reject(error);
      });
    });
  }

  /**
   * 取消运行
   */
  cancel(): void {
    this.abortController?.abort();
  }

  /**
   * 设置超时时间
   */
  setTimeout(timeout: number): void {
    this.timeout = timeout;
  }

  /**
   * 销毁
   */
  destroy(): void {
    this.cancel();
  }
}