import { readFile } from "node:fs/promises";
import path from "node:path";
import { pathToFileURL } from "node:url";
import {
  type DoctorOptions,
  diagnoseEkklesia,
  doctorExitCode,
  formatDoctorReport,
} from "../diagnostics/index.js";
import { type HostEnvironment, loadHostConfiguration } from "../host/index.js";
import { type ModulesDirectorySelection, resolveModulesDirectory } from "../modules/index.js";

interface ModuleSdkPackageDocument {
  readonly version?: unknown;
}

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

/**
 * Everything Doctor needs that comes from the repository itself rather than the deployment
 * environment, resolved by the caller so the environment mapping below stays pure and testable.
 */
export interface DoctorCommandMetadata {
  readonly moduleSdkVersion: string;
  readonly platformVersion: string;
  /** Where the platform is installed: Core's migrations live beneath it, and so does the
   * development default modules directory. Installed modules may live anywhere else. */
  readonly repositoryRoot: string;
  readonly runtimeRange: string;
  readonly runtimeVersion: string;
}

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;
}

/**
 * The modules directory exactly as `startApi` would choose it. An unusable configured value is not
 * thrown here, because Doctor must still produce a report: it is handed on as a required directory
 * for discovery to refuse, which reports it as a sanitized module-discovery failure.
 */
function doctorModulesDirectory(
  configured: string | undefined,
  repositoryRoot: string,
): ModulesDirectorySelection {
  try {
    return resolveModulesDirectory({ configured, repositoryRoot });
  } catch {
    return { modulesDirectory: configured ?? "", modulesDirectoryRequired: true };
  }
}

/**
 * Turns one deployment environment into Doctor's inputs.
 *
 * Every infrastructure value comes from `loadHostConfiguration` — the same function `apps/api` calls
 * with the same environment — so `pnpm doctor` and `startApi` cannot disagree about what this
 * deployment is configured to use. Doctor previously read its own subset here and silently omitted
 * object storage and module secrets entirely, which made it report a correctly configured
 * installation as having neither.
 *
 * Everything is handed over **raw**. Doctor validates it and reports a sanitized code, so a
 * malformed value appears in the report — which is the whole reason an operator runs this command —
 * instead of throwing before a report exists.
 */
export function createDoctorOptions(
  environment: HostEnvironment,
  metadata: DoctorCommandMetadata,
): DoctorOptions {
  const host = loadHostConfiguration(environment);
  return {
    clientAddress: host.clientAddress,
    coreMigrationsDirectory: path.join(metadata.repositoryRoot, "core", "drizzle"),
    databaseEnvironment: host.environment,
    databaseTransport: host.databaseTransport,
    databaseUrl: host.databaseUrl,
    identityConfiguration: { ...host.identity, environment: host.environment },
    mailConfiguration: host.mail,
    moduleDiscovery: {
      moduleSdkVersion: metadata.moduleSdkVersion,
      ...doctorModulesDirectory(host.modulesDirectory, metadata.repositoryRoot),
      platformVersion: metadata.platformVersion,
    },
    moduleSecrets: host.moduleSecrets,
    runtimeRange: metadata.runtimeRange,
    runtimeVersion: metadata.runtimeVersion,
    storageConfiguration: host.storage,
  };
}

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(
    createDoctorOptions(process.env, {
      moduleSdkVersion: requiredString(moduleSdkPackage.version),
      platformVersion: requiredString(rootPackage.version),
      repositoryRoot,
      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;
    });
}