import type { JSONSchema, typeofschema } from 'https://deno.land/x/enzastdlib/schema/mod.ts';

export const SCHEMA_ADD_PARAMETERS = {
    type: 'object',
    required: ['a', 'b'],

    additionalProperties: false,

    properties: {
        a: {
            type: 'number',
        },

        b: {
            type: 'number',
        },
    },
} as const satisfies JSONSchema;

export type AddParametersType = typeofschema<typeof SCHEMA_ADD_PARAMETERS>;

export const SCHEMA_ADD_RETURN = {
    type: 'object',
    required: ['sum'],

    additionalProperties: false,

    properties: {
        sum: {
            type: 'number',
        },
    },
} as const satisfies JSONSchema;

export type AddReturnType = typeofschema<typeof SCHEMA_ADD_RETURN>;

add.procedure.ts

import type { Procedure } from 'https://deno.land/x/enzastdlib/rpc-protocol/mod.ts';
import { parametersschema, resultschema } from 'https://deno.land/x/enzastdlib/rpc-protocol/mod.ts';

import type { AddParametersType, AddReturnType } from './add.schema.ts';
import { SCHEMA_ADD_PARAMETERS, SCHEMA_ADD_RETURN } from './add.schema.ts';

parametersschema(add, SCHEMA_ADD_PARAMETERS);
resultschema(add, SCHEMA_ADD_RETURN);
export function add(
    _payload: Procedure,
    parameters: AddParametersType,
): AddReturnType {
    const { a, b } = parameters;

    return {
        sum: a + b,
    };
}

mod.ts

import { makeStreamServer } from 'https://deno.land/x/enzastdlib/rpc-streams/mod.ts';

import { add } from './add.procedure.ts';

const command = new Deno.Command(..., {
    ...,

    // **NOTE**: IO must be set to work as pipes or else the IPC will not be usable
    // as Web Streams.
    stdin: 'piped',
    stdout: 'piped',
    stderr: 'piped',
});

const process = command.spawn();

const server = makeStreamServer({
    readable: process.stdout,
    writable: process.stdin,

    procedures: {
        add,
    },
});

server.serve();