require 'reek/smells/smell_detector'
require 'reek/smell_warning'

module Reek
  module Smells

    #
    # An Uncommunicative Name is a name that doesn't communicate its intent
    # well enough.
    # 
    # Poor names make it hard for the reader to build a mental picture
    # of what's going on in the code. They can also be mis-interpreted;
    # and they hurt the flow of reading, because the reader must slow
    # down to interpret the names.
    #
    # Currently +UncommunicativeParameterName+ checks for
    # * 1-character names
    # * names ending with a number
    #
    class UncommunicativeParameterName < SmellDetector

      SMELL_CLASS = 'UncommunicativeName'
      SMELL_SUBCLASS = self.name.split(/::/)[-1]
      PARAMETER_NAME_KEY = 'parameter_name'

      # The name of the config field that lists the regexps of
      # smelly names to be reported.
      REJECT_KEY = 'reject'

      DEFAULT_REJECT_SET = [/^.$/, /[0-9]$/, /[A-Z]/, /^_/]

      # The name of the config field that lists the specific names that are
      # to be treated as exceptions; these names will not be reported as
      # uncommunicative.
      ACCEPT_KEY = 'accept'

      DEFAULT_ACCEPT_SET = []

      def self.default_config
        super.merge(
          REJECT_KEY => DEFAULT_REJECT_SET,
          ACCEPT_KEY => DEFAULT_ACCEPT_SET
        )
      end

      def self.contexts      # :nodoc:
        [:defn, :defs]
      end

      #
      # Checks the given +context+ for uncommunicative names.
      #
      # @return [Array<SmellWarning>]
      #
      def examine_context(ctx)
        @reject_names = value(REJECT_KEY, ctx, DEFAULT_REJECT_SET)
        @accept_names = value(ACCEPT_KEY, ctx, DEFAULT_ACCEPT_SET)
        context_expression = ctx.exp
        context_expression.parameter_names.select do |name|
          is_bad_name?(name) && ctx.uses_param?(name)
        end.map do |name|
          SmellWarning.new(SMELL_CLASS, ctx.full_name, [context_expression.line],
                           "has the parameter name '#{name}'",
                           @source, SMELL_SUBCLASS, {PARAMETER_NAME_KEY => name.to_s})
        end
      end

      def is_bad_name?(name)
        var = name.to_s.gsub(/^[@\*\&]*/, '')
        return false if var == '*' or @accept_names.include?(var)
        @reject_names.detect {|patt| patt === var}
      end
    end
  end
end