// main.js
import {getIDsByTag, getIDsFromStorage, getReviewFromStorage, getTopIDsFromStorage} from "./localStorage.js";

// Run the init() function when the page has loaded
window.addEventListener("DOMContentLoaded", init);

function init() {
	//initial population of review container
	sortAndFilter(false, null);
	//Add the event listeners to dropdown and search bar
	initFormHandler();
}


/**
 * @param {Array<Object>} reviews An array of reviews
 */
function addReviewsToDocument(reviews) {
	let reviewBox = document.getElementById("review-container");
	reviews.forEach(review => {
		let newReview = document.createElement("review-card");
		newReview.data = review;
		reviewBox.append(newReview);
	});

}

/**
 * Adds the necessary event handlers to search-btn and sort
 */
function initFormHandler() {

	//grabbing search field
	let searchField = document.getElementById("search-bar");
	let searchBtn = document.getElementById("search-btn");
	let searchTag = null;
	//adding search functionality
	//TODO: Add ability to enter without refresh of search bar
	//filter by selected tag when button clicked
	searchBtn.addEventListener("click", function(){
		searchTag = searchField.value;
		sortAndFilter(searchTag);
	});

	//sort by selected method
	let sortMethod = document.getElementById("sort");
	sortMethod.addEventListener("input", function(){
		sortAndFilter(searchTag);
	});

	
}

/**
 * Deciphers sort and filter to populate the review-container
 * @param {string} searchTag tag name to filter by
 */
function sortAndFilter(searchTag){
	let reviewBox = document.getElementById("review-container");
	let sortMethod = document.getElementById("sort");
	//clear review container
	while(reviewBox.firstChild){
		reviewBox.removeChild(reviewBox.firstChild);
	}
	let reviewIDs = [];
	//sort method: most recent
	if(sortMethod.value == "recent"){
		//tag filtered most recent
		if(searchTag){
			reviewIDs = getIDsByTag(searchTag);
		} 
		//most recent
		else {
			reviewIDs = getIDsFromStorage();
		}
		//reversed for recency
		loadReviews(0, reviewIDs.reverse());
	} 
	//sort method: top rated
	else if (sortMethod.value == "top"){
		//tag filtered top rated
		if(searchTag){
			//intersection of top ids list and ids by tag in top ids order
			reviewIDs = getTopIDsFromStorage().filter(x => getIDsByTag(searchTag).includes(x));
		} 
		//top rated
		else {
			reviewIDs = getTopIDsFromStorage();
		}
		loadReviews(0, reviewIDs);
	}
}

/**
 * Populate review-container with 9 more reviews
 * @param {number} index review index to begin with
 * @param {number[]} reviewIDs ordered array of reviews
 */
function loadReviews(index, reviewIDs){
	let reviewBox = document.getElementById("review-container");
	let moreBtn = document.getElementById("more-btn");
	//delete load more button if exists
	if(moreBtn){
		reviewBox.removeChild(moreBtn);
	}
	let reviewArr = [];
	//check if there are more than 9 reviews left
	if(index + 9 > reviewIDs.length - 1){
		//add remaining reviews to review container
		for(let i = index; i < reviewIDs.length; i++){
			reviewArr.push(getReviewFromStorage(reviewIDs[i]));
		}
		addReviewsToDocument(reviewArr);
	} else {
		//add 9 more reviews to container
		for(let i = index; i < index + 9; i++){
			reviewArr.push(getReviewFromStorage(reviewIDs[i]));
		}
		addReviewsToDocument(reviewArr);
		//create and add load more button
		moreBtn = document.createElement("button");
		moreBtn.setAttribute("id", "more-btn");
		moreBtn.innerText = "Load More";
		//if load more clicked, load 9 more
		moreBtn.addEventListener("click", function(){loadReviews(index + 9, reviewIDs)});
		reviewBox.append(moreBtn);
	}

}