"use strict";

const defaultValue = require("default-value");
const nanoid = require("nanoid");
const jsonStringifyPreReplacer = require("../json-stringify-pre-replacer");

module.exports = function serialize(instance, options = {}) {
	let customSerializer = defaultValue(options.serializer, (value) => value);

	/* FIXME: Remove `serializer` argument and let this be specified on fields / type aliases instead? */
	let seenItems = new Map();

	let data = jsonStringifyPreReplacer(instance, (key, value) => {
		if (value == null) {
			return value;
		} else if (value._guardedCollectionType === "set") {
			return {
				_d_sT: "gS",
				entries: Array.from(value._source.values())
			};
		} else if (value._guardedCollectionType === "map") {
			return {
				_d_sT: "gM",
				entries: Array.from(value._source.entries())
			};
		} else if (value._type != null && value._type._isCustomType === true) {
			if (!seenItems.has(value)) {
				let objectID = nanoid();

				seenItems.set(value, objectID);

				value._type._ensureHash();

				return {
					_d_sT: "cT",
					type: value._type._typeHash,
					data: value._data,
					id: objectID
				};
			} else {
				return {
					_d_sT: "cTR",
					id: seenItems.get(value)
				};
			}
		} else {
			return customSerializer(value);
		}
	});

	return data;
};