import { initTRPC } from "@trpc/server";
import { TypeCompiler } from "@sinclair/typebox/compiler";
import { TRPCError } from "@trpc/server";
import type { TSchema } from "@sinclair/typebox";

/**
 * Initialization of tRPC backend
 * Should be done only once per backend!
 */
const t = initTRPC.create();

/**
 * Export reusable router and procedure helpers
 * that can be used throughout the router
 */
export const router = t.router;
export const publicProcedure = t.procedure;

/**
 * Generate a TRPC-compatible validator function given a Typebox schema.
 * This was copied from [https://github.com/sinclairzx81/typebox/blob/6cfcdc02cc813af2f1be57407c771fc4fadfc34a/example/trpc/readme.md].
 * @param schema A Typebox schema
 * @returns A TRPC-compatible validator function
 */
export function RpcType<T extends TSchema>(schema: T) {
  const check = TypeCompiler.Compile(schema);
  return (value: unknown) => {
    if (check.Check(value)) return value;
    const { path, message } = check.Errors(value).First();
    throw new TRPCError({
      message: `${message} for ${path}`,
      code: "BAD_REQUEST",
    });
  };
}