var users = [];
var posts = {};

const blockContainer = document.getElementById("block-container");
const postCountElem = document.getElementById("post-count");
const postTotalElem = document.getElementById("post-total");
const loader = document.getElementById("loader");

// then we'll define a variable for how many posts we want to increase the
// page by
const postIncrease = 9;
// and define a value to determine which page we're on
let currentPage = 1;

// how many times can we increase the content until we reach the max limit?
function getPageCount() {
    return Math.ceil(Object.keys(posts).length / postIncrease);
}

function getRandomColor() {
    const h = Math.floor(Math.random() * 360);
    return `hsl(${h}deg, 90%, 85%)`;
}

class Post {
    constructor(data) {
        this.id = data.id;
        this.username = data.associatedUser;
        this.content = data.body;
        this.replyTo = data.replyTo;

        this.replies = []
    }

    getIsReply() {
        return this.replyTo != "";
    }

    addReply(reply) {
        this.replies.push(reply);
    }

    getElement() {
        const postElem = document.createElement("div");
        postElem.className = "block post";
        postElem.style.backgroundColor = getRandomColor();

        // add a header to the post
        const headerElem = document.createElement("h1");
        headerElem.innerHTML = this.username;

        const profileLinkElem = document.createElement("a");
        profileLinkElem.setAttribute("href", "#");
        profileLinkElem.addEventListener("click", () => updateUserProfile(this.username));
        profileLinkElem.appendChild(headerElem);

        postElem.appendChild(profileLinkElem);

        const contentElem = document.createElement("p");
        contentElem.innerHTML = this.content;
        postElem.appendChild(contentElem);

        for (let i = 0; i < this.replies.length; i++) {
            const reply = this.replies[i];

            const commentElem = document.createElement("div");
            commentElem.style.backgroundColor = getRandomColor();

            const commentUserElem = document.createElement("h2");
            commentUserElem.innerHTML = reply.username;
            commentElem.appendChild(commentUserElem);

            const commentContentElem = document.createElement("p");
            commentContentElem.innerHTML = reply.content;
            commentElem.appendChild(commentContentElem);

            postElem.appendChild(commentElem);

            // TODO: indent 2nd-level replies
            for (let j = 0; j < reply.replies.length; j++) {
                const replyReply = reply.replies[j];

                const replyReplyElem = document.createElement("div");
                replyReplyElem.style.backgroundColor = getRandomColor();

                const replyReplyUserElem = document.createElement("h3");
                replyReplyUserElem.innerHTML = replyReply.username;
                replyReplyElem.appendChild(replyReplyUserElem);

                const replyReplyContentElem = document.createElement("p");
                replyReplyContentElem.innerHTML = replyReply.content;
                replyReplyElem.appendChild(replyReplyContentElem);

                postElem.appendChild(replyReplyElem);
            }
        }

        return postElem;
    }
}


function getRootPosts() {
    let result = [];
    for (var id in posts) {
        const post = posts[id];
        if (post.getIsReply())
            continue;

        result.push(post);
    }
    return result;
}


function addPosts(pageIdx) {
    currentPage = pageIdx;

    const startRange = (pageIdx - 1) * postIncrease;
    const endRange = currentPage == getPageCount()
        ? posts.length
        : pageIdx * postIncrease;

    postCountElem.innerHTML = endRange;

    const rootPosts = getRootPosts();

    for (let i = startRange + 1; i <= endRange; i++) {
        blockContainer.appendChild(rootPosts[i].getElement());
    }
}


function handleInfiniteScroll() {
    throttle(() => {
        const endOfPage = window.innerHeight + window.pageYOffset >= document.body.offsetHeight;

        if (endOfPage) {
            addPosts(currentPage + 1);
        }

        if (currentPage === getPageCount()) {
            removeInfiniteScroll();
        }
    }, 1000);
}


// limit how often we try to load new posts to maintain browser performance
var throttleTimer;
function throttle(callback, time) {
    if (throttleTimer) return;

    throttleTimer = true;

    setTimeout(() => {
        callback();
        throttleTimer = false;
    }, time);
}


function removeInfiniteScroll() {
    loader.remove();
    window.removeEventListener("scroll", handleInfiniteScroll);
}

function writePost() {
    // TODO: inject a new post element at the top of the feed
    console.log("write something interesting");

    setTimeout(() => {
    }, 500);

    const userName = "theChief";
    fetch("https://api.wayfarer.games/singularity/generate-posts.php", {
        method: "POST",
        mode: "cors",
        body: JSON.stringify({
            "user": userName,
            "interests": [
                "gen-ai",
                "blockchain",
                "nfts"
            ],
            "posting_style": "just the most truly inane takes"
        }),
        headers: {
            "Content-type": "application/json; charset=UTF-8"
        }
    })
        .then(response => response.json())
        .then(json => {
            // find the first post
            const children = blockContainer.childNodes;
            let firstPost = null;
            for (let i = 0; i < children.length; i++) {
                const child = children[i];
                const classes = child.className.split(" ");
                if (classes.some(c => c == "post")) {
                    firstPost = child;
                    break;
                }
            }

            // generate a post to insert before the first post
            const postData = {
                id: json.id,
                associatedUser: json.associatedUser,
                body: json.body
            };

            const post = new Post(postData);
            const postElem = post.getElement();

            blockContainer.insertBefore(postElem, firstPost);

            console.log(post);
        });
}

function addWritePostBlock() {
    const blockElem = document.createElement("div");
    blockElem.className = "block";
    blockElem.style.backgroundColor = "red";

    const buttonElem = document.createElement("a");
    buttonElem.setAttribute("href", "#");
    buttonElem.innerHTML = "Write something interesting for me!";
    buttonElem.addEventListener("click", writePost);
    blockElem.append(buttonElem);

    blockContainer.append(blockElem)
}

function init() {
    if (posts == undefined)
    {
        console.log("resource loading failed");
        return;
    }
    
    // need to load all the resources first
    const postCount = Object.keys(posts).length;
    if (users.length == 0 || postCount == 0)
        return;

    console.log(`loaded ${users.length} users and ${postCount} posts`);

    // TODO: add write post block
    addWritePostBlock();
    // TODO: add bio

    addPosts(currentPage);
    window.addEventListener("scroll", handleInfiniteScroll);
}

function loadDataFromEndpoint(endpoint, callback) {
    fetch(endpoint)
        .then(response => response.json())
        .then(json => {
            callback(json);
            init();
        });
}

loadDataFromEndpoint("https://api.wayfarer.games/singularity/users.json", json => { users = json.users; });
loadDataFromEndpoint("https://api.wayfarer.games/singularity/posts.json", json => {
    // first pass to instantiate all the posts
    for (let i = 0; i < json.content.length; i++) {
        const post = new Post(json.content[i]);
        posts[post.id] = post;
    }

    // second pass to link each reply to the appropriate parent
    for (const id in posts) {
        const post = posts[id];
        if (!post.getIsReply())
            continue;

        const parent = posts[post.replyTo];
        parent.addReply(post);
    }

    postTotalElem.innerHTML = Object.keys(posts).length;
});