require 'digest/sha1'

class Fingerprint

  attr_reader :notice, :api_key

  def self.generate(notice, api_key)
    self.new(notice, api_key).to_s
  end

  def initialize(notice, api_key)
    @notice = notice
    @api_key = api_key
  end

  def to_s
    Digest::SHA1.hexdigest(fingerprint_source.to_s)
  end

  def fingerprint_source
    {
      :file_or_message => file_or_message,
      :error_class => notice.error_class,
      :component => notice.component || 'unknown',
      :action => notice.action,
      :environment => notice.environment_name || 'development',
      :api_key => api_key
    }
  end

  def file_or_message
    @file_or_message ||= unified_message + notice.backtrace.fingerprint
  end

  # filter memory addresses out of object strings
  # example: "#<Object:0x007fa2b33d9458>" becomes "#<Object>"
  def unified_message
    notice.message.gsub(/(#<.+?):[0-9a-f]x[0-9a-f]+(>)/, '\1\2')
  end

end