module ViewComponent::PreviewActions

def default_preview_layout
  ViewComponent::Base.config.default_preview_layout
end

def determine_layout(layout_override = nil, prepend_views: true)
  return {} unless defined?(Rails.root)
  layout_declaration = {}
  if !layout_override.nil?
    # Allow component-level override, even if false (thus no layout rendered)
    layout_declaration[:layout] = layout_override
  elsif default_preview_layout.present?
    layout_declaration[:layout] = default_preview_layout
  end
  prepend_application_view_paths if layout_declaration[:layout].present? && prepend_views
  layout_declaration
end

def find_preview
  candidates = []
  params[:path].to_s.scan(%r{/|$}) { candidates << Regexp.last_match.pre_match }
  preview = candidates.detect { |candidate| ViewComponent::Preview.exists?(candidate) }
  if preview
    @preview = ViewComponent::Preview.find(preview)
  else
    raise AbstractController::ActionNotFound, "Component preview '#{params[:path]}' not found."
  end
end

def index
  @previews = ViewComponent::Preview.all
  @page_title = "Component Previews"
  render "view_components/index", **determine_layout
end

def prepend_application_view_paths
  prepend_view_path Rails.root.join("app/views") if defined?(Rails.root)
end

def prepend_preview_examples_view_path
  prepend_view_path(ViewComponent::Base.preview_paths)
end

def previews
  find_preview
  if params[:path] == @preview.preview_name
    @page_title = "Component Previews for #{@preview.preview_name}"
    render "view_components/previews", **determine_layout
  else
    prepend_application_view_paths
    prepend_preview_examples_view_path
    @example_name = File.basename(params[:path])
    @render_args = @preview.render_args(@example_name, params: params.permit!)
    layout = determine_layout(@render_args[:layout], prepend_views: false)[:layout]
    locals = @render_args[:locals]
    opts = {}
    opts[:layout] = layout if layout.present? || layout == false
    opts[:locals] = locals if locals.present?
    render "view_components/preview", opts
  end
end

def set_locale(&block)
  I18n.with_locale(params[:locale] || I18n.default_locale, &block)
end

def show_previews?
  ViewComponent::Base.config.show_previews
end