import { readFile } from "node:fs/promises";
import path from "node:path";
import { pathToFileURL } from "node:url";
import { diagnoseEkklesia, doctorExitCode, formatDoctorReport } from "../diagnostics/index.js";

interface ModuleSdkPackageDocument {
  readonly version?: unknown;
}

interface RootPackageDocument extends ModuleSdkPackageDocument {
  readonly engines?: {
    readonly node?: unknown;
  };
}

async function readJson(pathname: string): Promise<unknown> {
  return JSON.parse(await readFile(pathname, "utf8")) as unknown;
}

function rootPackageDocument(value: unknown): RootPackageDocument {
  if (typeof value !== "object" || value === null || Array.isArray(value)) {
    throw new TypeError("Invalid workspace package metadata.");
  }
  return value as RootPackageDocument;
}

function requiredString(value: unknown): string {
  if (typeof value !== "string" || value.length === 0) {
    throw new TypeError("Missing workspace package metadata.");
  }
  return value;
}

export async function runDoctorCommand(repositoryRoot = process.cwd()): Promise<number> {
  const [rootValue, moduleSdkValue] = await Promise.all([
    readJson(path.join(repositoryRoot, "package.json")),
    readJson(path.join(repositoryRoot, "packages", "module-sdk", "package.json")),
  ]);
  const rootPackage = rootPackageDocument(rootValue);
  const moduleSdkPackage = rootPackageDocument(moduleSdkValue);

  const report = await diagnoseEkklesia({
    databaseUrl: process.env.DATABASE_URL,
    moduleDiscovery: {
      moduleSdkVersion: requiredString(moduleSdkPackage.version),
      modulesDirectory: path.join(repositoryRoot, "modules"),
      platformVersion: requiredString(rootPackage.version),
    },
    runtimeRange: requiredString(rootPackage.engines?.node),
    runtimeVersion: process.versions.node,
  });

  console.log(formatDoctorReport(report).join("\n"));
  return doctorExitCode(report);
}

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

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