import * as z from "zod";

export { z };

/** Shared options bag mirroring TypeBox's `SchemaOptions`, used by all schema helpers in this module. */
export type SchemaOptions = {
  title?: string;
  description?: string;
  default?: unknown;
  error?: string;
  errorMessage?: string;
  excludeFromApiSpecGeneration?: boolean;
};

/** Resolves the validation error message from either `error` or `errorMessage` option. */
export const errorMessage = (options?: SchemaOptions) =>
  options?.error ?? options?.errorMessage;

/** Attaches non-undefined {@link SchemaOptions} fields to a schema via `.meta()`. */
export function withMetadata<T extends z.ZodType>(
  schema: T,
  options?: SchemaOptions,
): T {
  if (!options) return schema;

  const { error: _, ...metadata } = {
    ...options,
    errorMessage: errorMessage(options),
  };

  return schema.meta(metadata);
}

/** Applies {@link SchemaOptions} metadata to an object schema. */
export function withObjectOptions<T extends z.ZodObject>(
  schema: T,
  options?: SchemaOptions,
): T {
  return withMetadata(schema, options);
}

/** Drop-in replacement for `z.object()` that accepts {@link SchemaOptions} for metadata and validation. */
export function object<T extends z.ZodRawShape>(
  shape: T,
  options?: SchemaOptions,
) {
  return withObjectOptions(z.object(shape), options);
}

/** Like {@link object} but uses `z.strictObject()` — rejects unknown keys. Marks the schema with `x-strictObject` metadata for the OpenRPC generator. */
export function strictObject<T extends z.ZodRawShape>(
  shape: T,
  options?: SchemaOptions,
) {
  return withObjectOptions(z.strictObject(shape), options).meta({
    "x-strictObject": true,
  });
}

/** Drop-in replacement for `z.union()` with options-first arg order (matches TypeBox's `Type.Union`). */
export function union<
  T extends readonly [z.ZodType, z.ZodType, ...z.ZodType[]],
>(options: SchemaOptions | undefined, schemas: T) {
  return withMetadata(
    z.union(schemas, { error: errorMessage(options) }),
    options,
  );
}