import { spawn } from "node:child_process";

export type CommandResult = {
  command: string;
  args: string[];
  cwd: string;
  exitCode: number | null;
  signal: NodeJS.Signals | null;
  stdout: string;
  stderr: string;
};

export type CommandRunner = (command: string, args: string[], options: { cwd: string; timeoutMs?: number; env?: NodeJS.ProcessEnv }) => Promise<CommandResult>;

export const runCommand: CommandRunner = (command, args, options) =>
  new Promise((resolve, reject) => {
    const child = spawn(command, args, { cwd: options.cwd, env: options.env ?? process.env, stdio: ["ignore", "pipe", "pipe"] });
    let stdout = "";
    let stderr = "";
    let settled = false;
    let timedOut = false;
    const timer = options.timeoutMs
      ? setTimeout(() => {
          timedOut = true;
          child.kill("SIGKILL");
        }, options.timeoutMs)
      : undefined;

    child.stdout.on("data", (chunk: Buffer) => {
      stdout += chunk.toString("utf8");
    });
    child.stderr.on("data", (chunk: Buffer) => {
      stderr += chunk.toString("utf8");
    });
    child.on("error", (error) => {
      if (settled) return;
      settled = true;
      if (timer) clearTimeout(timer);
      reject(error);
    });
    child.on("close", (exitCode, signal) => {
      if (settled) return;
      settled = true;
      if (timer) clearTimeout(timer);
      if (timedOut) {
        stderr = `${stderr}\nCommand timed out after ${options.timeoutMs}ms`.trimStart();
      }
      resolve({ command, args, cwd: options.cwd, exitCode, signal, stdout, stderr });
    });
  });

export function formatCommand(command: string, args: string[]): string {
  return [command, ...args].join(" ");
}

export function tail(text: string, max = 12_000): string {
  return text.length > max ? text.slice(-max) : text;
}