module Capybara::Selenium::Find

def build_hints_js(uses_visibility, styles, position)
  functions = []
  hints_js = +''
  if uses_visibility && !is_displayed_atom.empty?
    hints_js << <<~VISIBILITY_JS
      var vis_func = #{is_displayed_atom};
    VISIBILITY_JS
    functions << :vis_func
  end
  if position
    hints_js << <<~POSITION_JS
      var position_func = function(el){
        return el.getBoundingClientRect();
      };
    POSITION_JS
    functions << :position_func
  end
  if styles.is_a? Hash
    hints_js << <<~STYLE_JS
      var style_func = function(el){
        var el_styles = window.getComputedStyle(el);
        return #{styles.keys.map(&:to_s)}.reduce(function(res, style){
          res[style] = el_styles[style];
          return res;
        }, {});
      };
    STYLE_JS
    functions << :style_func
  end
  hints_js << <<~EACH_JS
    return arguments[0].map(function(el){
      return [#{functions.join(',')}].map(function(fn){ return fn.call(null, el) });
    });
  EACH_JS
  [hints_js, functions]
end

def es_context
  respond_to?(:execute_script) ? self : driver
end

def filter_by_text(elements, texts)
  es_context.execute_script <<~JS, elements, texts
    var texts = arguments[1];
    return arguments[0].filter(function(el){
      var content = el.textContent.toLowerCase();
      return texts.every(function(txt){ return content.indexOf(txt.toLowerCase()) != -1 });
    })
  JS
end

def find_by(format, selector, uses_visibility:, texts:, styles:, position:)
  els = find_context.find_elements(format, selector)
  hints = []
  if (els.size > 2) && !ENV['DISABLE_CAPYBARA_SELENIUM_OPTIMIZATIONS']
    els = filter_by_text(els, texts) unless texts.empty?
    hints = gather_hints(els, uses_visibility: uses_visibility, styles: styles, position: position)
  end
  els.map.with_index { |el, idx| build_node(el, hints[idx] || {}) }
end

def find_css(selector, uses_visibility: false, texts: [], styles: nil, position: false, **_options)
  find_by(:css, selector, uses_visibility: uses_visibility, texts: texts, styles: styles, position: position)
end

def find_xpath(selector, uses_visibility: false, styles: nil, position: false, **_options)
  find_by(:xpath, selector, uses_visibility: uses_visibility, texts: [], styles: styles, position: position)
end

def gather_hints(elements, uses_visibility:, styles:, position:)
  hints_js, functions = build_hints_js(uses_visibility, styles, position)
  return [] unless functions.any?
  (es_context.execute_script(hints_js, elements) || []).map! do |results|
    hint = {}
    hint[:style] = results.pop if functions.include?(:style_func)
    hint[:position] = results.pop if functions.include?(:position_func)
    hint[:visible] = results.pop if functions.include?(:vis_func)
    hint
  end
rescue ::Selenium::WebDriver::Error::StaleElementReferenceError,
       ::Capybara::NotSupportedByDriverError
  # warn 'Unexpected Stale Element Error - skipping optimization'
  []
end

def is_displayed_atom # rubocop:disable Naming/PredicateName
  @@is_displayed_atom ||= begin # rubocop:disable Style/ClassVars
    browser.send(:bridge).send(:read_atom, 'isDisplayed')
  rescue StandardError
    # If the atom doesn't exist or other error
    ''
  end
end