import { spawn } from "node:child_process";
import path from "node:path";
import { loadEnvFile } from "node:process";
import { fileURLToPath, pathToFileURL } from "node:url";

const repositoryRoot = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..");

function isMissingFileError(error: unknown): boolean {
  return (
    typeof error === "object" &&
    error !== null &&
    "code" in error &&
    (error as { readonly code?: unknown }).code === "ENOENT"
  );
}

async function runCommand(command: string, arguments_: readonly string[]): Promise<number> {
  return await new Promise<number>((resolve) => {
    const child = spawn(command, arguments_, {
      cwd: repositoryRoot,
      stdio: "ignore",
    });
    child.once("error", () => resolve(1));
    child.once("exit", (code) => resolve(code ?? 1));
  });
}

export async function runDoctor(): Promise<number> {
  const buildExitCode = await runCommand("turbo", ["run", "build"]);
  if (buildExitCode !== 0) {
    console.error("Ekklesia Doctor build preparation failed. Run pnpm build for details.");
    return 1;
  }

  try {
    loadEnvFile(path.join(repositoryRoot, ".env"));
  } catch (error) {
    if (!isMissingFileError(error)) {
      console.error("Ekklesia Doctor configuration could not be loaded safely.");
      return 1;
    }
  }

  const moduleUrl = pathToFileURL(
    path.join(repositoryRoot, "core", "dist", "cli", "doctor.js"),
  ).href;
  const doctorModule = (await import(moduleUrl)) as {
    readonly runDoctorCommand?: unknown;
  };
  if (typeof doctorModule.runDoctorCommand !== "function") {
    throw new TypeError("Invalid Doctor command module.");
  }
  return await doctorModule.runDoctorCommand(repositoryRoot);
}

function isDirectExecution(): boolean {
  const entrypoint = process.argv[1];
  return (
    entrypoint !== undefined && import.meta.url === pathToFileURL(path.resolve(entrypoint)).href
  );
}

if (isDirectExecution()) {
  runDoctor()
    .then((exitCode) => {
      process.exitCode = exitCode;
    })
    .catch(() => {
      console.error("Ekklesia Doctor failed before diagnostics could be composed.");
      process.exitCode = 1;
    });
}