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require 'tsort'
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module ForemanMaintain
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class DependencyGraph
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include TSort
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attr_reader :graph, :collection, :labels
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def self.sort(collection)
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new(collection).tsort.map(&:ensure_instance)
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end
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def initialize(collection)
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@graph = Hash.new([])
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@collection = collection
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@steps_by_labels = @collection.group_by(&:label)
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generate_label_graph
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end
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def add_to_graph(key, dependencies = [])
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return unless key
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graph[key] = dependencies
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end
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def tsort_each_node(&block)
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@collection.each(&block)
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end
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def tsort_each_child(node, &block)
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graph.fetch(node).each(&block)
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end
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private
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def generate_label_graph
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collection.each do |object|
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klass = object.is_a?(Class) ? object : object.class
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klass.before.each do |label|
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add_to_graph(labels_to_objects(label).first, [object])
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end
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add_to_graph(object, labels_to_objects(klass.after))
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end
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end
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def labels_to_objects(labels)
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labels = Array(labels)
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labels.map { |label| @steps_by_labels[label] }.compact.flatten
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end
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end
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end
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