// The isolated, short-lived validation process of Module Package v1 verification (ADR 0049).
//
// The verifier forks this file with an empty environment and one JSON argument naming a candidate
// module's backend entrypoints. It imports each one, so a package whose code cannot load, or whose
// bundle still reaches for a dependency it does not contain, is refused before it is ever installed.
// Whatever the module's top-level code does happens here, in a process with no database URL, no
// secret, and no platform state, and that is discarded as soon as it reports.
//
// The result travels over the IPC channel, never stdout, so nothing a module prints can forge it.
// It carries fixed role and reason names only: never an error message, a path, or module output.
//
// Written as erasable TypeScript, so Node can run the source file directly in tests as well as the
// compiled file in the image. Its one relative import names the source file's own extension, which
// the build rewrites to `.js` (`rewriteRelativeImportExtensions`); that file follows the same rules.
import { pathToFileURL } from "node:url";
import {
  parseModuleRuntimeDefinition,
  parseModuleSchemaMetadataDefinition,
} from "@ekklesia/contracts";
import { parseModuleSchemaDefinition } from "./legacy-schema-definition.ts";

interface ProbeRequest {
  readonly databaseAbi?: 1;
  readonly moduleId: string;
  readonly version: string;
  readonly entrypoints: Readonly<Record<string, string>>;
}

interface ProbeFailure {
  readonly role: string;
  readonly reason: "contract" | "export" | "identity" | "load";
}

function defaultExport(namespace: unknown): unknown {
  return typeof namespace === "object" && namespace !== null && "default" in namespace
    ? (namespace as { default: unknown }).default
    : undefined;
}

async function probe(request: ProbeRequest): Promise<readonly ProbeFailure[]> {
  const failures: ProbeFailure[] = [];
  for (const role of Object.keys(request.entrypoints).sort()) {
    const entrypoint = request.entrypoints[role];
    if (entrypoint === undefined) {
      continue;
    }
    let namespace: unknown;
    try {
      namespace = await import(pathToFileURL(entrypoint).href);
    } catch {
      failures.push({ reason: "load", role });
      continue;
    }
    try {
      if (role === "server") {
        const definition = parseModuleRuntimeDefinition(defaultExport(namespace));
        if (definition.id !== request.moduleId || definition.version !== request.version) {
          failures.push({ reason: "identity", role });
        }
        if ((definition.database?.abi === 1) !== (request.databaseAbi === 1)) {
          failures.push({ reason: "contract", role });
        }
      } else if (role === "schema") {
        const definition =
          request.databaseAbi === 1
            ? parseModuleSchemaMetadataDefinition(defaultExport(namespace))
            : parseModuleSchemaDefinition(defaultExport(namespace));
        if (definition.moduleId !== request.moduleId) {
          failures.push({ reason: "identity", role });
        }
      }
    } catch {
      failures.push({ reason: "export", role });
    }
  }
  return failures;
}

function report(message: unknown): void {
  if (typeof process.send !== "function") {
    process.exitCode = 2;
    return;
  }
  process.send(message, () => {
    // A module may leave timers or handles behind; the probe's work is done either way.
    process.exit(0);
  });
}

let request: ProbeRequest | undefined;
try {
  request = JSON.parse(process.argv[2] ?? "") as ProbeRequest;
} catch {
  report({ failures: [{ reason: "load", role: "request" }] });
}
if (request !== undefined) {
  probe(request).then(
    (failures) => report({ failures }),
    () => report({ failures: [{ reason: "load", role: "probe" }] }),
  );
}