Refs #5586 @4h; First `action_links` refactor

- Implement new API
- Migrate the LineDecorator
- ensure no change on the "lines/index" view

1 files changed, 124 insertions, 0 deletions

diff --git a/lib/af83/decorator.rb b/lib/af83/decorator.rb
new file mode 100644
index 000000000..f1570008f
--- /dev/null
+++ b/lib/af83/decorator.rb
@@ -0,0 +1,124 @@
+class AF83::Decorator < Draper::Decorator
+  def self.action_link args={}
+    args[:if] = @_condition if args[:if].nil?
+    options, link_options = parse_options args
+
+    link = Link.new(link_options)
+    yield link if block_given?
+    raise IncompleteLinkDefinition.new(link.errors) unless link.complete?
+
+    weight = options[:weight] || 1
+    @_action_links ||= []
+    @_action_links[weight] ||= []
+    @_action_links[weight] << link
+  end
+
+  def self.with_condition condition, &block
+    @_condition = condition
+    instance_eval &block
+    @_condition = nil
+  end
+
+  def self.action_links action
+    (@_action_links || []).flatten.compact.select{|l| l.for_action?(action)}
+  end
+
+  def action_links action=:index
+    self.class.action_links(action)\
+    .map{|l| l.bind_to_context(self)}\
+    .select{|l| l.enabled?}
+  end
+
+  def check_policy policy
+    _object = policy.to_s == "create" ? object.class : object
+    method = "#{policy}?"
+    h.policy(_object).send(method)
+  end
+
+  private
+  def self.parse_options args
+    options = {}
+    %i(primary secondary permission weight).each do |k|
+      options[k] = args.delete(k) if args.has_key?(k)
+    end
+    link_options = args.dup
+    actions = args.delete :actions
+    actions ||= args.delete :on
+    actions ||= [args.delete(:action)]
+    actions = [actions] unless actions.is_a?(Array)
+    link_options[:_actions] = actions.compact
+    link_options[:_if] = args.delete(:if)
+    link_options[:_policy] = args.delete(:policy)
+    [options, link_options]
+  end
+
+  class Link
+    REQUIRED_ATTRIBUTES = %i(href content)
+
+    attr_reader :context
+
+    def initialize options={}
+      @options = options
+    end
+
+    def bind_to_context context
+      @context = context
+      self
+    end
+
+    def method *args
+      link_method *args
+    end
+
+    def method_missing name, *args, &block
+      if block_given?
+        @options[name] = block
+      elsif args.size == 0
+        out = @options[name]
+        out = context.instance_exec(&out) if out.is_a?(Proc)
+        out
+      else
+        @options[name] = args.first
+      end
+    end
+
+    def complete?
+      @missing_attributes = REQUIRED_ATTRIBUTES.select{|a| !@options[a].present?}
+      @missing_attributes.empty?
+    end
+
+    def enabled_actions
+      @options[:_actions].map(&:to_s) || []
+    end
+
+    def for_action? action
+      enabled_actions.empty? || enabled_actions.include?(action.to_s)
+    end
+
+    def enabled?
+      enabled = false
+      if @options[:_if].nil?
+        enabled = true
+      elsif @options[:_if].is_a?(Proc)
+        enabled = context.instance_exec(&@options[:_if])
+      else
+        enabled = !!@options[:_if]
+      end
+
+      enabled = enabled && check_policy(@options[:_policy]) if @options[:_policy].present?
+
+      enabled
+    end
+
+    def check_policy(policy)
+      @context.check_policy policy
+    end
+
+    def errors
+      "Missing attributes: #{@missing_attributes.to_sentence}"
+    end
+  end
+
+  class IncompleteLinkDefinition < RuntimeError
+  end
+end