// search from https://github.com/onweru/compose

function initializeSearch(index) {
  const searchKeys = ['title', 'link', 'body', 'id'];

  const searchPageElement = elem('#searchpage');

  const searchOptions = {
    ignoreLocation: true,
    findAllMatches: true,
    includeScore: true,
    shouldSort: true,
    keys: searchKeys,
    threshold: 0.0
  };

  index = new Fuse(index, searchOptions);

  function minQueryLen(query) {
    query = query.trim();
    const queryIsFloat = parseFloat(query);
    const minimumQueryLength = queryIsFloat ? 1 : 2;
    return minimumQueryLength;
  }

  function searchResults(results=[], query="", passive = false) {
    let resultsFragment = new DocumentFragment();
    let showResults = elem('.search_results');
    if(passive) {
      showResults = searchPageElement;
    }
    emptyEl(showResults);

    const queryLen = query.length;
    const requiredQueryLen = minQueryLen(query);

    if(results.length && queryLen >= requiredQueryLen) {
      let resultsTitle = createEl('h3');
      resultsTitle.className = 'search_title';
      resultsTitle.innerText = quickLinks;
      if(passive) {
        resultsTitle.innerText = searchResultsLabel;
      }
      resultsFragment.appendChild(resultsTitle);
      if(!searchPageElement) {
        results = results.slice(0,8);
      } else {
        results = results.slice(0,12);
      }
      results.forEach(function(result){
        let item = createEl('a');
        item.href = `${result.link}?query=${query}`;
        item.className = 'search_result';
        item.style.order = result.score;
        if(passive) {
          pushClass(item, 'passive');
          let itemTitle = createEl('h3');
          itemTitle.textContent = result.title;
          item.appendChild(itemTitle);

          let itemDescription = createEl('p');
          // position of first search term instance
          let queryInstance = result.body.indexOf(query);
          itemDescription.textContent = `... ${result.body.substring(queryInstance, queryInstance + 200)} ...`;
          item.appendChild(itemDescription);
        } else {
          item.textContent = result.title;
        }
        resultsFragment.appendChild(item);
      });
    }

    if(queryLen >= requiredQueryLen) {
      if (!results.length) {
        showResults.innerHTML = `<span class="search_result">${noMatchesFound}</span>`;
      }
    } else {
      showResults.innerHTML = `<label for="find" class="search_result">${ queryLen > 1 ? shortSearchQuery : typeToSearch }</label>`
    }

    showResults.appendChild(resultsFragment);
  }

  function search(searchTerm, passive = false) {
    if(searchTerm.length) {
      let rawResults = index.search(searchTerm);
      rawResults = rawResults.map(function(result){
        const score = result.score;
        const resultItem = result.item;
        resultItem.score = (parseFloat(score) * 50).toFixed(0);
        return resultItem;
      });

      passive ? searchResults(rawResults, searchTerm, true) : searchResults(rawResults, searchTerm);

    } else {
      passive ? searchResults([], "", true) : searchResults();
    }
  }

  function liveSearch() {
    const searchField = elem(searchFieldClass);

    if (searchField) {
      searchField.addEventListener('input', function() {
        const searchTerm = searchField.value.trim().toLowerCase();
        search(searchTerm);
      });

      if(!searchPageElement) {
        searchField.addEventListener('search', function(){
          const searchTerm = searchField.value.trim().toLowerCase();
          if(searchTerm.length)  {
            window.location.href = new URL(`search/?query=${searchTerm}`, rootURL).href;
          }
        });
      }
    }
  }

  function findQuery(query = 'query') {
    const urlParams = new URLSearchParams(window.location.search);
    if(urlParams.has(query)){
      let c = urlParams.get(query);
      return c;
    }
    return "";
  }

  function passiveSearch() {
    if(searchPageElement) {
      const searchTerm = findQuery();
      search(searchTerm, true);

      // search actively after search page has loaded
      const searchField = elem(searchFieldClass);

      if(searchField) {
        searchField.addEventListener('input', function() {
          const searchTerm = searchField.value.trim().toLowerCase();
          search(searchTerm, true);
          wrapText(searchTerm, main);
        });
      }
    }
  }

  function hasSearchResults() {
    const searchResults = elem('.results');
    if(searchResults) {
        const body = searchResults.innerHTML.length;
        return [searchResults, body];
    }
    return false
  }

  function clearSearchResults() {
    let searchResults = hasSearchResults();
    if(searchResults) {
      searchResults = searchResults[0];
      searchResults.innerHTML = "";
      // clear search field
      const searchField = elem(searchFieldClass);
      searchField.value = "";
    }
  }

  function onEscape(fn){
    window.addEventListener('keydown', function(event){
      if(event.code === "Escape") {
        fn();
      }
    });
  }

  let main = elem('main');
  if(!main) {
    main = elem('.main');
  }

  searchPageElement ? false : liveSearch();
  passiveSearch();

  wrapText(findQuery(), main);

  onEscape(clearSearchResults);

  window.addEventListener('click', function(event){
    const target = event.target;
    const isSearch = target.closest(searchClass) || target.matches(searchClass);
    if(!isSearch && !searchPageElement) {
      clearSearchResults();
    }
  });
}

window.addEventListener('load', function() {
  fetch(new URL("index.json", rootURL).href)
  .then(response => response.json())
  .then(function(data) {
    data = data.length ? data : [];
    initializeSearch(data);
  })
  .catch((error) => console.error(error));
});