module SvelteOnRails::ViewHelpers

def file_case_sensitive_messsage(filename)
  conf = SvelteOnRails::Configuration.instance
  ff = conf.frontend_folder
  cf = conf.components_folder
  "svelte-on-rails gem, view helper #svelte_component\n\n" +
    "File found but Upper and lower case letters are incorrect:\n" +
    "(This check is only on development environments when watch_changes is true)\n\n" +
    "#{conf.components_folder_full + "#{filename}.svelte"}\n\n" +
    "Your configurations are:\nfrontend_folder: «#{ff}»\ncomponents_folder: «#{cf}»\n.. and the filename attribute for the view helper: «#{filename}»\n"
end

def file_not_found_messsage(filename)
  conf = SvelteOnRails::Configuration.instance
  ff = conf.frontend_folder
  cf = conf.components_folder
  "svelte-on-rails gem, view helper #svelte_component\n\nFile not found:\n" +
    "#{conf.components_folder_full + "#{filename}.svelte"}\n\n" +
    "Your configurations are:\n\nfrontend_folder: «#{ff}»\ncomponents_folder: «#{cf}»\n.. and the filename attribute for the view helper: «#{filename}»\n"
end

def svelte_component(filename, props = {})
  # check filename
  conf = SvelteOnRails::Configuration.instance
  cff = conf.components_folder_full
  file_path = cff + "#{filename}.svelte"
  if !File.exist?(file_path)
    raise file_not_found_messsage(filename)
  elsif conf.watch_changes? && !SvelteOnRails::Lib::Utils.file_exist_case_sensitive?(cff, filename + '.svelte')
    # on development environments we check case sensitivity too
    msg = "File found but Upper and lower case letters are incorrect\n" +
      "(This check is only on development environments when watch_changes is true):\n."
    raise file_case_sensitive_messsage(filename)
  end
  # check what to do
  rss = if props.key?(:ssr)
          props.delete(:ssr)
        else
          conf.ssr
        end
  unless [true, false, :auto].include?(rss)
    raise "Only true, false or auto are allowed for the argument #ssr"
  end
  ssr = (rss == :auto && request.headers['X-Turbo-Request-ID'].blank? || rss)
  hydrate = if props.key?(:hydrate)
              props[:hydrate]
            else
              true
            end
  # separate hashes
  props.delete(:hydrate)
  props.delete(:ssr)
  options = props.slice(:class, :id, :style)
  props.delete(:class)
  props.delete(:id)
  props.delete(:style)
  # set up html
  options[:class] = options[:class].to_s + ' svelte-component'
  options[:class] += ' please-hydrate-me-svelte-on-rails' if hydrate
  options[:data] ||= {}
  options[:data][:props] = props.to_json
  options[:data][:svelte_component] = filename
  if ssr
    # render server side
    start_time = Time.now
    comp = SvelteOnRails::Compiler.new(filename)
    comp.compile_if_changes
    rend = SvelteOnRails::Renderer.new(compiled_file: comp.compiled_file)
    res = rend.render(props)
    time = Time.now - start_time
    Rails.logger.info "  Rendered #{filename}.svelte server-side: #{time.round(3)}ms"
    content_tag(:div, options) do
      r = content_tag(:style, res['css'], type: 'text/css')
      r << res['html'].html_safe
    end
  else
    # render empty element
    Rails.logger.info "  Rendered #{filename}.svelte as empty element that will be mounted on the client side"
    content_tag(:div, options) {}
  end
end