import { createRequire } from "node:module";

const require = createRequire(import.meta.url);
const sourceWindowsProcess = new URL(
  "../../src/windows/WindowsOwnedProcess.ts",
  import.meta.url,
).href;

/** Load the source owner without requiring a generated dist tree. */
export async function loadWindowsOwnedProcessClass() {
  const { tsImport } = await import("tsx/esm/api");
  const source = await tsImport(sourceWindowsProcess, import.meta.url);
  return source.WindowsOwnedProcess;
}

/** Start an owned Windows command while preserving cross-spawn's shim rules. */
export function createWindowsOwnedCommand(options) {
  const {
    WindowsOwnedProcess,
    command,
    arguments: arguments_,
    cwd,
    environment,
    authority,
  } = options;
  // This pinned private parser is cross-spawn's own resolution and cmd-shim
  // boundary. Keep its compatibility coupling here instead of copying its rules.
  const parse = require("cross-spawn/lib/parse");
  const parsed = parse(command, arguments_, { cwd, env: environment });
  if (
    typeof parsed !== "object" ||
    parsed === null ||
    typeof parsed.command !== "string" ||
    !Array.isArray(parsed.args) ||
    !parsed.args.every((argument) => typeof argument === "string") ||
    typeof parsed.options !== "object" ||
    parsed.options === null ||
    (parsed.options.windowsVerbatimArguments !== undefined &&
      typeof parsed.options.windowsVerbatimArguments !== "boolean")
  )
    throw new TypeError(
      "cross-spawn returned an unsupported Windows command shape",
    );
  // cross-spawn keeps the user's spelling in `command` for a resolved .exe
  // (for example bare `node`), while `file` is the PATH-resolved executable.
  // The native boundary intentionally requires an absolute application path.
  const executable =
    parsed.command === command && typeof parsed.file === "string"
      ? parsed.file
      : parsed.command;
  return new WindowsOwnedProcess(
    executable,
    parsed.args,
    cwd,
    environment,
    parsed.options.windowsVerbatimArguments === true,
    {
      protocolStdin: true,
      ...(authority === undefined ? {} : { authority }),
    },
  );
}

/** Own a native command until its exact Job Object close event. */
export function superviseWindowsOwnedProcess(
  child,
  { retryIntervalMs = 1_000, onCleanupDiagnostic = () => {} } = {},
) {
  const childStdin = child.stdin ?? undefined;
  let jobClosed = false;
  let stdinClosed = childStdin === undefined;
  let settled = false;
  let closeResult;
  let hasFirstError = false;
  let firstError;
  let retryTimer;
  let cleanupInFlight = false;
  let lastCleanupFailure;
  let reportedCleanupFailure = false;

  const finished = new Promise((resolveResult, reject) => {
    child.on("error", handleError);
    child.once("close", (code, signal) => {
      jobClosed = true;
      closeResult = { code, signal };
      clearTimeout(retryTimer);
      child.off("error", handleError);
      finishWhenClosed(resolveResult, reject);
    });
    childStdin?.on("error", handleError);
    childStdin?.once("close", () => {
      stdinClosed = true;
      childStdin.off("error", handleError);
      finishWhenClosed(resolveResult, reject);
    });
  });

  function finishWhenClosed(resolveResult, reject) {
    if (!jobClosed || !stdinClosed || settled) return;
    settled = true;
    if (reportedCleanupFailure) {
      onCleanupDiagnostic({ type: "cleanup-recovered" });
      reportedCleanupFailure = false;
      lastCleanupFailure = undefined;
    }
    if (hasFirstError) reject(firstError);
    else resolveResult(closeResult);
  }

  function handleError(cause) {
    if (!hasFirstError) {
      hasFirstError = true;
      firstError = cause;
    }
    requestCleanup();
  }

  function scheduleRetry() {
    if (jobClosed || retryTimer !== undefined) return;
    // Keep this timer referenced: until Job Object close, it is the supervisor's
    // live ownership observer even after IPC disconnect or stdin EOF.
    retryTimer = setTimeout(() => {
      retryTimer = undefined;
      requestCleanup();
    }, retryIntervalMs);
  }

  function reportFailure(reason) {
    if (jobClosed) return;
    if (reportedCleanupFailure && lastCleanupFailure === reason) return;
    lastCleanupFailure = reason;
    reportedCleanupFailure = true;
    onCleanupDiagnostic({ type: "cleanup-failed", reason });
  }

  function requestCleanup() {
    if (jobClosed || cleanupInFlight) return;
    clearTimeout(retryTimer);
    retryTimer = undefined;
    cleanupInFlight = true;
    let cleanup;
    try {
      cleanup = child.cleanup();
    } catch (cause) {
      reportFailure(cause instanceof Error ? cause.message : String(cause));
      cleanupInFlight = false;
      scheduleRetry();
      return;
    }
    void Promise.resolve(cleanup)
      .then((result) => {
        if (!result.cleaned) {
          reportFailure(
            result.reason ?? "Windows Job Object cleanup did not complete",
          );
          return;
        }
        if (!jobClosed)
          reportFailure(
            "Windows Job Object cleanup reported success before its close event",
          );
      })
      .catch((cause) => {
        reportFailure(cause instanceof Error ? cause.message : String(cause));
      })
      .finally(() => {
        cleanupInFlight = false;
        scheduleRetry();
      });
  }

  return { finished, requestCleanup };
}