require 'mspec/helpers/io'

class ComplainMatcher
  def initialize(complaint)
    @complaint = complaint
  end

  def matches?(proc)
    @saved_err = $stderr
    @verbose = $VERBOSE
    begin
      err = $stderr = IOStub.new
      $VERBOSE = false
      Thread.current[:in_mspec_complain_matcher] = true
      proc.call
    ensure
      $VERBOSE = @verbose
      $stderr = @saved_err
      Thread.current[:in_mspec_complain_matcher] = false
    end

    @warning = err.to_s
    unless @complaint.nil?
      case @complaint
      when Regexp
        return false unless @warning =~ @complaint
      else
        return false unless @warning == @complaint
      end
    end

    return @warning.empty? ? false : true
  end

  def failure_message
    if @complaint.nil?
      ["Expected a warning", "but received none"]
    elsif @complaint.kind_of? Regexp
      ["Expected warning to match: #{@complaint.inspect}", "but got: #{@warning.chomp.inspect}"]
    else
      ["Expected warning: #{@complaint.inspect}", "but got: #{@warning.chomp.inspect}"]
    end
  end

  def negative_failure_message
    if @complaint.nil?
      ["Unexpected warning: ", @warning.chomp.inspect]
    elsif @complaint.kind_of? Regexp
      ["Expected warning not to match: #{@complaint.inspect}", "but got: #{@warning.chomp.inspect}"]
    else
      ["Expected warning: #{@complaint.inspect}", "but got: #{@warning.chomp.inspect}"]
    end
  end
end

module MSpecMatchers
  private def complain(complaint=nil)
    ComplainMatcher.new(complaint)
  end
end