class RSpec::Core::World

def announce_exclusion_filter
  if exclusion_filter && RSpec.world.example_count.zero?
    @configuration.reporter.message(
      "No examples were matched. Perhaps #{exclusion_filter.inspect} is excluding everything?")
    example_groups.clear
  end
end

def announce_inclusion_filter
  if inclusion_filter
    if @configuration.run_all_when_everything_filtered? && RSpec.world.example_count.zero?
      @configuration.reporter.message "No examples were matched by #{inclusion_filter.inspect}, running all"
      @configuration.clear_inclusion_filter
      filtered_examples.clear
    else
      @configuration.reporter.message "Run filtered using #{inclusion_filter.inspect}"
    end
  end
end

def apply?(predicate, conditions)
  lambda {|example| example.metadata.apply?(predicate, conditions)}
end

def apply_exclusion_filters(examples, conditions={})
  examples.reject(&apply?(:any?, conditions))
end

def apply_inclusion_filters(examples, conditions={})
  examples.select(&apply?(:any?, conditions))
end

def configure_group(group)
  @configuration.configure_group(group)
end

def declaration_line_numbers
  @line_numbers ||= example_groups.inject([]) do |lines, g|
    lines + g.declaration_line_numbers
  end
end

def example_count
  example_groups.collect {|g| g.descendants}.flatten.inject(0) { |sum, g| sum += g.filtered_examples.size }
end

def exclusion_filter
  @configuration.exclusion_filter
end

def find_hook(hook, scope, group)
  @configuration.find_hook(hook, scope, group)
end

def inclusion_filter
  @configuration.filter
end

def initialize(configuration=RSpec.configuration)
  @configuration = configuration
  @example_groups = []
  @filtered_examples = Hash.new { |hash,group|
    hash[group] = begin
      examples = group.examples.dup
      examples = apply_exclusion_filters(examples, exclusion_filter) if exclusion_filter
      examples = apply_inclusion_filters(examples, inclusion_filter) if inclusion_filter
      examples.uniq
    end
  }
end

def preceding_declaration_line(filter_line)
  declaration_line_numbers.inject(nil) do |highest_prior_declaration_line, line|
    line <= filter_line ? line : highest_prior_declaration_line
  end
end

def register(example_group)
  example_groups << example_group
  example_group
end

def shared_example_groups
  @shared_example_groups ||= {}
end