import { SpawnOptions } from "node:child_process";

export type PlatformProcessKillerDeps = {
  platform: NodeJS.Platform;
  spawnProcess: (command: string, args: string[], options: SpawnOptions) => SpawnedKillerProcess;
  killProcess: (pid: number, signal: NodeJS.Signals) => void;
  log: (...args: unknown[]) => void;
};

type SpawnedKillerProcess = {
  on: (event: "error", listener: (error: Error) => void) => unknown;
};

export function killProcessTree(pid: number, signal: NodeJS.Signals, deps: PlatformProcessKillerDeps): boolean {
  if (!Number.isSafeInteger(pid) || pid <= 0) {
    deps.log(`Invalid pid for process tree termination: ${pid}`);
    return false;
  }

  if (deps.platform === "win32") {
    return killWindowsProcessTree(pid, signal, deps);
  }

  return killPosixProcessTree(pid, signal, deps.killProcess);
}

function killWindowsProcessTree(
  pid: number,
  signal: NodeJS.Signals,
  deps: Pick<PlatformProcessKillerDeps, "spawnProcess" | "log">,
): boolean {
  const args = ["/pid", String(pid), "/T", ...(signal === "SIGKILL" ? ["/F"] : [])];
  const killer = deps.spawnProcess("taskkill", args, {
    stdio: "ignore",
    shell: false,
    windowsHide: true,
  });

  killer.on("error", (error) => {
    deps.log(`taskkill error for pid=${pid}`, error);
  });

  return true;
}

function killPosixProcessTree(pid: number, signal: NodeJS.Signals, killProcess: PlatformProcessKillerDeps["killProcess"]): boolean {
  try {
    killProcess(-pid, signal);
    return true;
  } catch {
    try {
      killProcess(pid, signal);
      return true;
    } catch {
      return false;
    }
  }
}