"use strict";

import { mutate, random_item } from './mutate.mjs';

let display_options = 3;

let initial_words = [
	"rockets",
	"cheese",
	"treasure",
	"island"
]

window.addEventListener("load", (_event) => {
	const el_starting_word = document.querySelector("#starting-word");
	const el_starting_regen = document.querySelector("#starting-regen");
	
	if(el_starting_word.value.length === 0)
		el_starting_word.value = random_item(initial_words);
	
	handle_starting_keyup();
	
	el_starting_word.addEventListener("keyup", handle_starting_keyup);
	el_starting_regen.addEventListener("click", handle_starting_keyup);
	el_starting_regen.addEventListener("mouseup", handle_starting_keyup);
	el_starting_regen.addEventListener("touchend", handle_starting_keyup);
});

function handle_starting_keyup(_event) {
	const el_starting_word = document.querySelector("#starting-word");
	const el_mutations = document.querySelector("#mutations");
	
	el_mutations.replaceChildren(); // Empty node of all children
	
	mutation_step(el_starting_word.value);
}

function handle_mutation_word_keyup(event) {
	// 1: Find DOM elements
	const el_mutations = document.querySelector("#mutations");
	const el_step = event.target.closest(".mutation-step");
	const el_word = event.target.closest(".mutation-option");
	const els_word = el_step.querySelectorAll(".mutation-option");
	
	// 2: Update UI - Change classes, Remove all subsequent mutation steps
	for(let i = 0; i < els_word.length; i++)
		els_word[i].classList.remove("selected");
	
	el_word.classList.add("selected");
	
	while(el_step.nextElementSibling !== null)
		el_step.parentNode.removeChild(el_step.nextElementSibling);
	
	// 3: Do a new mutation step
	el_mutations.appendChild(document.createElement("hr"))
	mutation_step(el_word.dataset.word);
}

function mutation_step(word) {
	// 0: Validate input
	if(typeof word !== "string")
		throw new Error(`Error: Expected argument 1 (word) to be of type string, but got value of type ${typeof word}.`);
	
	// 1: Find DOM elements
	const el_mutations = document.querySelector("#mutations");
	
	// 2: Generate mutations
	// TODO: Eliminate duplicates
	const words_new = Array(display_options).fill(null)
		.map(() => mutate(word));
	
	// 3: Update DOM
	let el_step = document.createElement("div");
	el_step.classList.add("mutation-step");
	for(let word_item of words_new) {
		let el_word = document.createElement("span");
		el_word.classList.add("mutation-option");
		el_word.appendChild(document.createTextNode(word_item));
		el_word.dataset.word = word_item;
		el_step.appendChild(el_word);
		el_word.addEventListener("click", handle_mutation_word_keyup);
		el_word.addEventListener("touchend", handle_mutation_word_keyup);
		el_word.addEventListener("mouseup", handle_mutation_word_keyup);
	}
	
	el_mutations.appendChild(el_step);
	
	window.scrollTo(0,document.body.scrollHeight);
}