class AtURI {
  /** @param {string} uri */
  constructor(uri) {
    if (!uri.startsWith('at://')) {
      throw new URLError(`Not an at:// URI: ${uri}`);
    }

    let parts = uri.split('/');

    if (parts.length != 5) {
      throw new URLError(`Invalid at:// URI: ${uri}`);
    }

    this.repo = parts[2];
    this.collection = parts[3];
    this.rkey = parts[4];
  }
}

/**
 * @typedef {object} PaginatorType
 * @property {(callback: (boolean) => void) => void} loadInPages
 * @property {(() => void)=} scrollHandler
 * @property {ResizeObserver=} resizeObserver
 */

window.Paginator = {
  loadInPages(callback) {
    if (this.scrollHandler) {
      document.removeEventListener('scroll', this.scrollHandler);
    }

    if (this.resizeObserver) {
      this.resizeObserver.disconnect();
    }

    let loadIfNeeded = () => {
      if (window.pageYOffset + window.innerHeight > document.body.offsetHeight - 500) {
        callback(loadIfNeeded);
      }
    };

    callback(loadIfNeeded);

    document.addEventListener('scroll', loadIfNeeded);
    const resizeObserver = new ResizeObserver(loadIfNeeded);
    resizeObserver.observe(document.body);

    this.scrollHandler = loadIfNeeded;
    this.resizeObserver = resizeObserver;
  }
};

/**
 * @template T
 * @param {string} tag
 * @param {string | object} params
 * @param {new (...args: any[]) => T} type
 * @returns {T}
 */

function $tag(tag, params, type) {
  let element;
  let parts = tag.split('.');

  if (parts.length > 1) {
    let tagName = parts[0];
    element = document.createElement(tagName);
    element.className = parts.slice(1).join(' ');
  } else {
    element = document.createElement(tag);
  }

  if (typeof params === 'string') {
    element.className = element.className + ' ' + params;
  } else if (params) {
    for (let key in params) {
      if (key == 'text') {
        element.innerText = params[key];
      } else if (key == 'html') {
        element.innerHTML = params[key];
      } else {
        element[key] = params[key];
      }
    }
  }

  return /** @type {T} */ (element);
}

/**
 * @template {HTMLElement} T
 * @param {string} name
 * @param {new (...args: any[]) => T} [type]
 * @returns {T}
 */

function $id(name, type) {
  return /** @type {T} */ (document.getElementById(name));
}

/**
 * @template {HTMLElement} T
 * @param {Node | EventTarget | null} element
 * @param {new (...args: any[]) => T} [type]
 * @returns {T}
 */

function $(element, type) {
  return /** @type {T} */ (element);
}

/** @param {string} uri, @returns {AtURI} */

function atURI(uri) {
  return new AtURI(uri);
}

function castToInt(value) {
  if (value === undefined || value === null || typeof value == "number") {
    return value;
  } else {
    return parseInt(value, 10);
  }
}

/** @param {string} html, @returns {string} */

function escapeHTML(html) {
  return html.replace(/&/g, '&')
             .replace(/</g, '&lt;')
             .replace(/>/g,'&gt;');
}

/** @param {json} feedPost, @returns {number} */

function feedPostTime(feedPost) {
  let timestamp = feedPost.reason ? feedPost.reason.indexedAt : feedPost.post.record.createdAt;
  return Date.parse(timestamp);
}

/** @param {string} html, @returns {string} */

function sanitizeHTML(html) {
  return DOMPurify.sanitize(html, {
    ALLOWED_TAGS: [
      'a', 'b', 'blockquote', 'br', 'code', 'dd', 'del', 'div', 'dl', 'dt', 'em', 'font',
      'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'hr', 'i', 'li', 'ol', 'p', 'q', 'pre', 's', 'span', 'strong',
      'sub', 'sup', 'u', 'wbr', '#text'
    ],
    ALLOWED_ATTR: [
      'align', 'alt', 'class', 'clear', 'color', 'dir', 'href', 'lang', 'rel', 'title', 'translate'
    ]
  });
}

/** @returns {string} */

function getLocation() {
  return location.origin + location.pathname;
}

/** @param {object} error */

function showError(error) {
  console.log(error);
  alert(error);
}

/** @param {Date} date1, @param {Date} date2, @returns {boolean} */

function sameDay(date1, date2) {
  return (
    date1.getDate() == date2.getDate() &&
    date1.getMonth() == date2.getMonth() &&
    date1.getFullYear() == date2.getFullYear()
  );
}

/** @param {Post} post, @returns {string} */

function linkToPostThread(post) {
  return linkToPostById(post.author.handle, post.rkey);
}

/** @param {string} handle, @param {string} postId, @returns {string} */

function linkToPostById(handle, postId) {
  let url = new URL(getLocation());
  url.searchParams.set('author', handle);
  url.searchParams.set('post', postId);
  return url.toString();
}