import type { ZodOptionalDef } from 'zod/v3';
import type { JsonSchema7Type } from '../parseDef';
import { parseDef } from '../parseDef';
import type { Refs } from '../Refs';

export const parseOptionalDef = (
  def: ZodOptionalDef,
  refs: Refs,
  forceResolution: boolean,
): JsonSchema7Type | undefined => {
  if (
    refs.propertyPath &&
    refs.currentPath.slice(0, refs.propertyPath.length).toString() === refs.propertyPath.toString()
  ) {
    return parseDef(def.innerType._def, { ...refs, currentPath: refs.currentPath }, forceResolution);
  }

  // `not: {}` accepts no JSON values and is unsupported by strict Structured Outputs.
  // Keep the wrapper, but generate only its real branch at the correct reference path.
  // Override callbacks retain their existing output and path contract.
  const omitNeverBranch = refs.openaiStrictMode && !refs.override;
  const innerSchema = parseDef(
    def.innerType._def,
    {
      ...refs,
      currentPath: [...refs.currentPath, 'anyOf', omitNeverBranch ? '0' : '1'],
    },
    forceResolution,
  );

  return innerSchema
    ? {
        anyOf: omitNeverBranch ? [innerSchema] : [{ not: {} }, innerSchema],
      }
    : {};
};