import type { Semigroup } from "./semigroup.ts";
import * as SG from "./semigroup.ts";
import * as N from "./number.ts";
import { pipe } from "./fn.ts";

type Person = { name: string, age: number };
const person = (name: string, age: number): Person => ({ name, age });

// Chooses the longest string, defaulting to left when equal
const longestString: Semigroup<string> = {
  concat: (right) => (left) => right.length > left.length ? right : left,
};

// This semigroup will merge two people, choosing the longest
// name and the oldest age
const { concat } = SG.struct<Person>({
  name: longestString,
  age: N.SemigroupNumberMax,
})

const brandon = pipe(
  person("Brandon Blaylock", 12),
  concat(person("Bdon", 17)),
  concat(person("Brandon", 30))
); // brandon === { name: "Brandon Blaylock", age: 30 }