# Bacon -- small RSpec clone.
# "Truth will sooner come out from error than from confusion." ---Francis Bacon

module Bacon
  VERSION = "0.2"
  
  Counter = Hash.new(0)
  ErrorLog = ""
  Shared = Hash.new { |_, name|
    raise NameError, "no such context: #{name.inspect}"
  }

  RestrictName    = //  unless defined? RestrictName
  RestrictContext = //  unless defined? RestrictContext

  module SpecDoxOutput
    def handle_specification(name)
      puts name
      yield
      puts
    end

    def handle_requirement(description)
      print "- #{description}"
      error = yield
      if error.empty?
        puts
      else
        puts " [#{error}]"
      end
    end

    def handle_summary
      puts Bacon::ErrorLog
      puts "%d specifications (%d requirements), %d failures, %d errors" % 
           [Counter[:specifications], Counter[:requirements],
            Counter[:failed],         Counter[:errors]]
    end
  end

  module TestUnitOutput
    def handle_specification(name)
      yield
    end

    def handle_requirement(description)
      error = yield
      if error.empty?
        print "."
      else
        print error[0..0]
      end
    end

    def handle_summary
      puts
      puts Bacon::ErrorLog
      puts "%d tests, %d assertions, %d failures, %d errors" % 
           [Counter[:specifications], Counter[:requirements],
            Counter[:failed],         Counter[:errors]]
    end
  end

  module TapOutput
    def handle_specification(name)
      yield
    end

    def handle_requirement(description)
      Bacon::ErrorLog.replace ""
      error = yield
      if error.empty?
        printf "ok %-8d # %s\n" % [Counter[:specifications], description]
      else
        printf "not ok %-4d # %s: %s\n" %
          [Counter[:specifications], description, error]
        puts Bacon::ErrorLog.strip.gsub(/^/, '# ') 
      end
    end

    def handle_summary
      puts "1..#{Counter[:specifications]}"
      puts "# %d tests, %d assertions, %d failures, %d errors" % 
           [Counter[:specifications], Counter[:requirements],
            Counter[:failed],         Counter[:errors]]
    end
  end

  extend SpecDoxOutput          # default

  class Error < RuntimeError
    attr_accessor :count_as
    
    def initialize(count_as, message)
      @count_as = count_as
      super message
    end
  end
  
  class Context
    def initialize(name, &block)
      @before = []
      @after = []
      @name = name

      return  unless name =~ RestrictContext
      Bacon.handle_specification(name) do
        instance_eval(&block)
      end
    end

    def before(&block); @before << block; end
    def after(&block);  @after << block; end

    def behaves_like(name)
      instance_eval &Bacon::Shared[name]
    end

    def it(description, &block)
      return  unless description =~ RestrictName
      Bacon::Counter[:specifications] += 1
      run_requirement description, block
    end

    def run_requirement(description, spec)
      Bacon.handle_requirement description do
        begin
          @before.each { |block| instance_eval(&block) }
          instance_eval(&spec)
          @after.each { |block| instance_eval(&block) }
        rescue Object => e
          ErrorLog << "#{e.class}: #{e.message}\n"
          e.backtrace.find_all { |line| line !~ /bin\/bacon|\/bacon\.rb:\d+/ }.
            each_with_index { |line, i|
            ErrorLog << "\t#{line}#{i==0?": "+@name + " - "+description:""}\n"
          }
          ErrorLog << "\n"
          
          if e.kind_of? Bacon::Error
            Bacon::Counter[e.count_as] += 1
            e.count_as.to_s.upcase
          else
            Bacon::Counter[:errors] += 1
            "ERROR: #{e.class}"
          end
        else
          ""
        end
      end      
    end

    def raise?(*args, &block)
      block.raise?(*args)
    end

    def throw?(*args, &block)
      block.throw?(*args)
    end
  end
end


class Object
  def true?; false; end
  def false?; false; end
end

class TrueClass
  def true?; true; end
end

class FalseClass
  def false?; true; end
end

class Proc
  def raise?(*exceptions)
    call
  rescue *(exceptions.empty? ? RuntimeError : exceptions) => e
    e
  # do not rescue other exceptions.
  else
    false
  end

  def throw?(sym)
    catch(sym) {
      call
      return false
    }
    return true
  end
end

class Float
  def close?(to, delta)
    (to.to_f - self).abs <= delta.to_f
  rescue
    false
  end
end

class Object
  def should(*args, &block)
    Should.new(self).be(*args, &block)
  end
end

module Kernel
  private

  def describe(name, &block)
    Bacon::Context.new(name, &block)
  end

  def shared(name, &block)
    Bacon::Shared[name] = block
  end
end


class Should
  # Kills ==, ===, =~, eql?, equal?, frozen?, instance_of?, is_a?,
  # kind_of?, nil?, respond_to?, tainted?
  instance_methods.each { |method|
    undef_method method  if method =~ /\?|^\W+$/
  }
  
  def initialize(object)
    @object = object
    @negated = false
  end

  def not(*args, &block)
    @negated = !@negated
    
    if args.empty?
      self
    else
      be(*args, &block)
    end
  end

  def be(*args, &block)
    case args.size
    when 0
      self
    else
      block = args.shift  unless block_given?
      satisfy(*args, &block)
    end
  end
    
  alias a  be
  alias an be
  
  def satisfy(*args, &block)
    if args.size == 1 && String === args.first
      description = args.shift
    else
      description = ""
    end

    r = yield(@object, *args)
    unless @negated ^ r
      raise Bacon::Error.new(:failed, description)
    end
    Bacon::Counter[:requirements] += 1
    @negated ^ r ? r : false
  end

  def method_missing(name, *args, &block)
    name = "#{name}?"  if name.to_s =~ /\w[^?]\z/
    
    desc = @negated ? "not " : ""
    desc << @object.inspect << "." << name.to_s
    desc << "(" << args.map{|x|x.inspect}.join(", ") << ") failed"
      
    satisfy(desc) { |x|
      x.__send__(name, *args, &block)
    }
  end

  def equal(value); self == value; end
  def match(value); self =~ value; end

  def identical_to(value); self.equal? value; end
  alias same_as identical_to
end