class RuboCop::Cop::Style::UnneededInterpolation

def self.autocorrect_incompatible_with
  [Style::LineEndConcatenation]
end

def autocorrect(node)
  embedded_node = node.children.first
  if variable_interpolation?(embedded_node)
    autocorrect_variable_interpolation(embedded_node, node)
  elsif single_variable_interpolation?(embedded_node)
    autocorrect_single_variable_interpolation(embedded_node, node)
  else
    autocorrect_other(embedded_node, node)
  end
end

def autocorrect_other(embedded_node, node)
  loc = node.loc
  embedded_loc = embedded_node.loc
  lambda do |corrector|
    corrector.replace(loc.begin, '')
    corrector.replace(loc.end, '')
    corrector.replace(embedded_loc.begin, '(')
    corrector.replace(embedded_loc.end, ').to_s')
  end
end

def autocorrect_single_variable_interpolation(embedded_node, node)
  variable_loc = embedded_node.children.first.loc
  replacement = "#{variable_loc.expression.source}.to_s"
  ->(corrector) { corrector.replace(node.loc.expression, replacement) }
end

def autocorrect_variable_interpolation(embedded_node, node)
  replacement = "#{embedded_node.loc.expression.source}.to_s"
  ->(corrector) { corrector.replace(node.loc.expression, replacement) }
end

def embedded_in_percent_array?(node)
  node.parent && node.parent.array_type? &&
    percent_literal?(node.parent)
end

def implicit_concatenation?(node)
  node.parent && node.parent.dstr_type?
end

def interpolation?(node)
  variable_interpolation?(node) || node.begin_type?
end

def on_dstr(node)
  add_offense(node) if single_interpolation?(node)
end

def single_interpolation?(node)
  node.children.one? &&
    interpolation?(node.children.first) &&
    !implicit_concatenation?(node) &&
    !embedded_in_percent_array?(node)
end

def single_variable_interpolation?(node)
  node.children.one? && variable_interpolation?(node.children.first)
end

def variable_interpolation?(node)
  node.variable? || node.reference?
end