class Lookbook::Preview

def layout(layout_name)
  @layout = layout_name
end

def preview_name
  name.chomp("Preview").underscore
end

def render(component = nil, **args, &block)
  if component.nil?
    {
      type: :view,
      template: args[:template] || Lookbook.config.preview_template,
      args: args,
      locals: args[:locals] || {},
      assigns: args[:assigns] || {},
      block: block
    }
  else
    {
      type: component.is_a?(String) ? :view : :component,
      args: args,
      block: block,
      component: component,
      locals: {},
      template: Lookbook.config.preview_template
    }
  end
end

def render_args(scenario, params: {})
  scenario_params_names = instance_method(scenario).parameters.map(&:last)
  provided_params = params.slice(*scenario_params_names).to_h.symbolize_keys
  result = provided_params.empty? ? new.public_send(scenario) : new.public_send(scenario, **provided_params)
  result ||= {}
  result[:template] = scenario_template_path(scenario) if result[:template].nil?
  @layout = nil unless defined?(@layout)
  result.merge(layout: @layout)
end

def render_with_template(template: nil, locals: nil)
  {
    type: :template,
    template: template,
    locals: locals.to_h
  }
end

def scenario_template_path(scenario)
  preview_name = name.chomp("Preview").underscore
  preview_path =
    Engine.preview_paths.detect do |path|
      Dir["#{path}/#{preview_name}_preview/#{scenario}.html.*"].first
    end
  if preview_path.nil?
    raise(
      PreviewTemplateError,
      "A preview template for scenario #{scenario} doesn't exist.\n\n" \
      "To fix this issue, create a template for the scenario."
    )
  end
  path = Dir["#{preview_path}/#{preview_name}_preview/#{scenario}.html.*"].first
  Pathname.new(path)
    .relative_path_from(Pathname.new(preview_path))
    .to_s
    .sub(/\..*$/, "")
end