import { execSync } from "node:child_process";
import type { ToolEntry } from "./types.js";

const MAX_OUTPUT = 10000;

export const shellExecTool: ToolEntry = {
  definition: {
    type: "function",
    function: {
      name: "shell_exec",
      description: "Execute a shell command and return stdout + stderr.",
      parameters: {
        type: "object",
        properties: {
          command: { type: "string", description: "Shell command to run" },
          timeout: { type: ["number", "null"], description: "Timeout in seconds (default: 30)" },
        },
        required: ["command"],
      },
    },
  },
  handler: async (args: string): Promise<string> => {
    try {
      const parsed = JSON.parse(args) as { command: string; timeout: number | null };
      const timeoutMs = (parsed.timeout ?? 30) * 1000;
      const output = execSync(parsed.command, {
        encoding: "utf-8",
        timeout: timeoutMs,
        stdio: ["pipe", "pipe", "pipe"],
        maxBuffer: MAX_OUTPUT * 2,
      });
      return output.length > MAX_OUTPUT ? `${output.slice(0, MAX_OUTPUT)}\n...(truncated)` : output;
    } catch (err: unknown) {
      if (
        err &&
        typeof err === "object" &&
        "status" in err &&
        (err as { status: unknown }).status === null
      ) {
        return "Error: command timed out";
      }
      if (err && typeof err === "object" && "stderr" in err) {
        const e = err as { stderr: string; stdout: string; status: number };
        const combined = `${e.stdout ?? ""}${e.stderr ?? ""}`;
        return combined.length > MAX_OUTPUT
          ? `${combined.slice(0, MAX_OUTPUT)}\n...(truncated)`
          : combined || `Error: command exited with status ${e.status}`;
      }
      return `Error: ${err instanceof Error ? err.message : String(err)}`;
    }
  },
};