function getSortBy() {
  let sortByLastCommitInput = document.getElementById('sortByDate');
  if (sortByLastCommitInput === null) {
    return 'date';
  } else {
    return sortByLastCommitInput.checked ? 'date' : 'stars';
  }
}

function getTagSortBy() {
  let tagSortByNumThemes = document.getElementById('tagSortByNumThemes');
  if (tagSortByNumThemes === null) {
    return 'numThemes';
  } else {
    return tagSortByNumThemes.checked ? 'numThemes' : 'name';
  }
}

function getFeatureSortBy() {
  let featureSortByNumThemes = document.getElementById('featureSortByNumThemes');
  if (featureSortByNumThemes === null) {
    return 'numThemes';
  } else {
    return featureSortByNumThemes.checked ? 'numThemes' : 'name';
  }
}

function getSortedThemes(themeList, sortedBy) {
  if (sortedBy === 'date') {
    return themeList.sort((a, b) => b.date_in_seconds - a.date_in_seconds);
  } else {
    return themeList.sort((a, b) => b.num_stars - a.num_stars);
  }
}

function getSelectedTags() {
  let tagSelectionInputs = document.getElementsByClassName('tagSelectionInput');
  if (tagSelectionInputs.length > 0) {
    return [...tagSelectionInputs].filter((x) => x.checked).map((y) => y.value);
  } else {
    return [];
  }
}

function getSelectedFeatures() {
  let featureSelectionInputs = document.getElementsByClassName('featureSelectionInput');
  if (featureSelectionInputs.length > 0) {
    return [...featureSelectionInputs].filter((x) => x.checked).map((y) => y.value);
  } else {
    return [];
  }
}

function getFilteredThemes(selectedTags, selectedFeatures) {
  if ((selectedTags.length === 0) && selectedFeatures.length === 0) {
    return themes;
  } else {
    return themes
      .filter((x) => selectedTags.every((y) => x.tags.includes(y)) )
      .filter((z) => selectedFeatures.every((w) => z.features.includes(w)) );
  }
}

function buildResults() {
  let resultsDiv = document.getElementById('results');
  resultsDiv.innerHTML = '';
  let resultsTable = document.createElement("table");
  resultsTable.id = 'resultsTable';
  resultsTable.style.border = '1px solid black';
  resultsTable.style.fontSize = '.9rem';

  let resultsTableHeadRow = document.createElement("tr");
  resultsDiv.appendChild(resultsTable);
  resultsTable.appendChild(resultsTableHeadRow);

  let themeTH = document.createElement("th");
  themeTH.innerHTML = "theme";
  resultsTableHeadRow.appendChild(themeTH);

  let dateTH = document.createElement("th");
  dateTH.innerHTML = "date";
  resultsTableHeadRow.appendChild(dateTH);

  let starsTH = document.createElement("th");
  starsTH.innerHTML = "stars";
  resultsTableHeadRow.appendChild(starsTH);

  let commitTH = document.createElement("th");
  commitTH.innerHTML = "commit";
  resultsTableHeadRow.appendChild(commitTH);

  let selectedTags = getSelectedTags();
  let selectedFeatures = getSelectedFeatures();
  let sortedBy = getSortBy();
  let filtered_themes = getFilteredThemes(selectedTags, selectedFeatures);
  let sorted_themes = getSortedThemes(filtered_themes, sortedBy);
  sorted_themes.forEach(theme => addThemeTableRow(theme));

  buildSelectionMenu(sorted_themes, sortedBy, selectedTags, selectedFeatures);
};

buildResults();