require 'erb' # It is referenced on line 56
module Approvals
  class Approval
    class << self
      attr_accessor :namer
    end

    attr_reader :subject, :namer, :failure
    def initialize(subject, options = {})
      @subject = subject
      @namer = options[:namer] || default_namer(options[:name])
      @format = options[:format] || identify_format
    end

    def default_namer(name)
      Approvals::Approval.namer || Namers::DefaultNamer.new(name)
    end

    # Add a Proc that tests if subject is a kind of format
    IDENTITIES = {
      hash: Proc.new(){|subject|subject.respond_to? :each_pair},
      array: Proc.new(){|subject|subject.respond_to? :each_with_index},      
    }
    
    def identify_format
      IDENTITIES.each_pair do |format, id_test|
        return format if id_test.call(subject)
      end
      # otherwise
      return :txt
    end

    def writer
      @writer ||= Writer.for(@format)
    end

    def verify
      unless File.exists?(namer.output_dir)
        FileUtils.mkdir_p(namer.output_dir)
      end

      writer.write(subject, received_path)

      unless approved?
        fail_with "Approval file \"#{approved_path}\" not found."
      end

      unless received_matches?
        fail_with "Received file \"#{received_path}\" does not match approved \"#{approved_path}\"."
      end

      success!
    end

    def success!
      File.delete received_path
    end

    def approved?
      File.exists? approved_path
    end

    BINARY_FORMATS = [:binary]
    
    def received_matches?
      if BINARY_FORMATS.include?(@format) # Read without ERB
        IO.read(received_path).chomp == IO.read(approved_path).chomp
      else
        IO.read(received_path).chomp == ERB.new(IO.read(approved_path).chomp).result
      end
    end

    def fail_with(message)
      Dotfile.append(diff_path)

      if subject.respond_to?(:on_failure)
        subject.on_failure.call(approved_text) if approved?
        subject.on_failure.call(received_text)
      end

      error = ApprovalError.new("Approval Error: #{message}")
      error.approved_path = approved_path
      error.received_path = received_path

      raise error
    end

    def diff_path
      "#{received_path} #{approved_path}"
    end

    def full_path(state)
      "#{namer.output_dir}#{namer.name}.#{state}.#{writer.extension}"
    end

    def name
      namer.name
    end

    def approved_path
      full_path('approved')
    end

    def received_path
      full_path('received')
    end

    def approved_text
      File.read approved_path
    end

    def received_text
      File.read received_path
    end
  end
end