class ViewComponent::Preview

def all
  load_previews if descendants.empty?
  descendants
end

def examples
  public_instance_methods(false).map(&:to_s).sort
end

def exists?(preview)
  all.any? { |p| p.preview_name == preview }
end

def find(preview)
  all.find { |p| p.preview_name == preview }
end

def layout(layout_name)
  @layout = layout_name
end

def load_previews
  Array(preview_paths).each do |preview_path|
    Dir["#{preview_path}/**/*_preview.rb"].sort.each { |file| require_dependency file }
  end
end

def preview_example_template_path(example)
  preview_path = Array(preview_paths).detect do |preview_path|
    Dir["#{preview_path}/#{preview_name}_preview/#{example}.html.*"].first
  end
  if preview_path.nil?
    raise PreviewTemplateError, "preview template for example #{example} does not exist"
  end
  path = Dir["#{preview_path}/#{preview_name}_preview/#{example}.html.*"].first
  Pathname.new(path)
          .relative_path_from(Pathname.new(preview_path))
          .to_s
          .sub(/\..*$/, "")
end

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

def preview_paths
  Base.preview_paths
end

def render(component, **args, &block)
  {
    args: args,
    block: block,
    component: component,
    locals: {},
    template: "view_components/preview",
  }
end

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

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