export const b = {
  init: 'activatePostImages getUserData',
}

const POST_IMAGES_SELECTOR = 'img.post-image:not(aside img.post-image)'
const WHOAMI_ENDPOINT = '/api/whoami/'
const THREAD_PERM_ENDPOINT = '/api/thread-permission/'
const TOGGLE_REACTION_ENDPOINT = '/api/toggle-reaction/'
const REPLACE_REACTIONS_ENDPOINT = '/hyperapi/reactions/'

const getThreadId = () => {
  const scheme = window.location.pathname.split("/");
  if (scheme[1] !== 'threads' || scheme[2] === 'new') {
    return -1;
  }
  return parseInt(scheme[2]);
}

let images = [];
let currentIndex = 0;
let currentUser = null;

let reactionMenuState = {};

export function activatePostImages(_, __, ___) {
  const images = document.querySelectorAll(POST_IMAGES_SELECTOR);
  images.forEach(image => {
    image.style.cursor = 'pointer';
    image.dataset.s = 'collectImages';
  });
}

export function collectImages(_, sender, el) {
  if (!el.contains(sender)) return;
  images = Array.from(el.querySelectorAll(POST_IMAGES_SELECTOR));
  currentIndex = images.indexOf(sender);
  b.trigger('showLightbox');
}

export function showLightbox(_, __, el) {
  const originalImg = images[currentIndex];
  const lightboxImg = el.querySelector('img');
  const anchor = el.querySelector('a');
  anchor.href = originalImg.src;
  lightboxImg.src = originalImg.src;
  lightboxImg.alt = originalImg.alt;

  if (!el.open) {
    el.showModal();
  }

  b.trigger('lightboxSetCounter');
}

export function closeLightbox(_, __, el) {
  el.close();
}

export function lightboxSetCounter(_, __, el) {
  el.innerText = `${currentIndex + 1}/${images.length}`;
}

export function lightboxNext(_, __, ___) {
  if (images.length == 1) return;
  currentIndex++;
  if (currentIndex >= images.length) {
    currentIndex = 0;
  }
  b.trigger('showLightbox');
}

export function lightboxPrevious(_, __, ___) {
  if (images.length == 1) return;
  currentIndex--;
  if (currentIndex < 0) {
    currentIndex = images.length - 1;
  }
  b.trigger('showLightbox');
}

export async function getUserData(_, __, ___) {
  currentUser = await b.getData(WHOAMI_ENDPOINT);
  b.trigger('highlightMentions');
  const d = (await b.getData(`${THREAD_PERM_ENDPOINT}${getThreadId()}`)).can_post;
  if (d) {
    b.trigger('enableReactionMenuButton');
    b.trigger('enableReactionButtons');
  } else {
    b.trigger('disableReactionMenuButton');
  }
}

export function highlightMentions(_, __, el) {
  if (!el) return;

  if (el.dataset.username === currentUser.username) {
    el.classList.add('me');
  }
}

export function openReactionMenu(ev, sender, el) {
  if (!el) return;
  if (reactionMenuState.state === undefined) {
    el.addEventListener('toggle', e => {
      if (e.newState === 'closed') {
        reactionMenuState.state = 'closed';
      }
    });
  }

  if (reactionMenuState.state === 'open' && reactionMenuState.invoker === sender) {
    el.hidePopover();
    return;
  }

  // TODO: [el, sender].prop(key) searches for ancestors with attr [data-${key}] if current element does not have `dataset[key]` but dataset transforms key names whereas css does not
  reactionMenuState.post = sender.prop('postid');

  reactionMenuState.invoker = sender;
  reactionMenuState.state = 'open';
  el.showPopover();

  const bRect = sender.getBoundingClientRect();
  const scrollY = window.scrollY;

  el.style.left = `${bRect.left}px`;
  el.style.top = `${bRect.bottom + scrollY}px`;
}

export function closeReactionMenu(_, __, el) {
  el.hidePopover();
}

export async function toggleReaction(_, sender, __) {
  const emoji = sender.dataset.emoji;
  const post = sender.prop('postid') ? sender.prop('postid') : reactionMenuState.post;

  const res = await fetch(TOGGLE_REACTION_ENDPOINT, {
    method: 'POST',
    body: JSON.stringify({ reaction: emoji, post: post }),
    headers: {
      'content-type': 'application/json',
    },
  });
  if (res.status !== 200) {
    return;
  }

  b.send({ postId: post }, 'replaceReactionButtons');
}

export async function replaceReactionButtons(payload, __, el) {
  if (payload.postId !== el.prop('postid')) return;
  const res = await fetch(`${REPLACE_REACTIONS_ENDPOINT}${payload.postId}`);
  if (res.status !== 200) {
    return;
  }
  const body = await res.text();
  const p = new DOMParser();
  const e = p.parseFromString(body, 'text/html').body;
  el.replaceChildren(...e.children);
  el.childNodes.forEach(b => {
    if (!b instanceof HTMLButtonElement) return;
    b.disabled = false;
  })
}

export function disableReactionMenuButton(_, __, el) {
  el.title = 'You do not have permission to add reactions to this post.';
}

export function enableReactionMenuButton(_, __, el) {
  el.disabled = false;
  el.title = '';
}

export function enableReactionButtons(_, __, el) {
  el.disabled = false;
}