/**
 * utilities for working with JS Dates
 *
 * @module
 */

import * as Either from "effect/Either";
import { type Codec, decodingError } from "./Codec.js";

export const iso8601ToDate: Codec<string, Date, unknown> = {
  encode: (value: Date) =>
    Number.isNaN(value.valueOf())
      ? Either.left(new Error("invalid date"))
      : Either.right(value.toISOString()),
  decode: (value) => {
    if (value instanceof Date) {
      return Number.isNaN(value.valueOf())
        ? Either.left(new Error("invalid date"))
        : Either.right(value);
    }
    switch (typeof value) {
      case "number":
        return Either.right(new Date(value));
      case "string": {
        const parsed = new Date(value);
        if (!value.includes("T")) {
          // Date constructor assumes UTC for strings without time component
          parsed.setMinutes(parsed.getMinutes() + parsed.getTimezoneOffset());
        }

        return Number.isNaN(parsed.valueOf())
          ? Either.left(new Error("invalid date string"))
          : Either.right(parsed);
      }
      default:
        return Either.left(decodingError(value));
    }
  },
};

/**
 * convert between Date und string. Invalid values are treated as a right undefined
 */
export const iso8601ContentAttribute__maybeDate: Codec<
  string,
  undefined | Date
> = {
  encode: (value) => {
    return value == null ? Either.right("") : iso8601ToDate.encode(value);
  },
  decode: (value) =>
    value === "" || value == null
      ? Either.right(undefined)
      : iso8601ToDate.decode(value),
};