# copied from activesupport

=begin
Copyright (c) 2005-2013 David Heinemeier Hansson

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
=end

class Object
  # An object is blank if it's false, empty, or a whitespace string.
  # For example, '', '   ', +nil+, [], and {} are all blank.
  #
  # This simplifies:
  #
  #   if address.nil? || address.empty?
  #
  # ...to:
  #
  #   if address.blank?
  def blank?
    respond_to?(:empty?) ? empty? : !self
  end

  # An object is present if it's not <tt>blank?</tt>.
  def present?
    !blank?
  end

  # Returns object if it's <tt>present?</tt> otherwise returns +nil+.
  # <tt>object.presence</tt> is equivalent to <tt>object.present? ? object : nil</tt>.
  #
  # This is handy for any representation of objects where blank is the same
  # as not present at all. For example, this simplifies a common check for
  # HTTP POST/query parameters:
  #
  #   state   = params[:state]   if params[:state].present?
  #   country = params[:country] if params[:country].present?
  #   region  = state || country || 'US'
  #
  # ...becomes:
  #
  #   region = params[:state].presence || params[:country].presence || 'US'
  def presence
    self if present?
  end
end

class NilClass
  # +nil+ is blank:
  #
  #   nil.blank? # => true
  def blank?
    true
  end
end

class FalseClass
  # +false+ is blank:
  #
  #   false.blank? # => true
  def blank?
    true
  end
end

class TrueClass
  # +true+ is not blank:
  #
  #   true.blank? # => false
  def blank?
    false
  end
end

class Array
  # An array is blank if it's empty:
  #
  #   [].blank?      # => true
  #   [1,2,3].blank? # => false
  alias_method :blank?, :empty?
end

class Hash
  # A hash is blank if it's empty:
  #
  #   {}.blank?                # => true
  #   { key: 'value' }.blank?  # => false
  alias_method :blank?, :empty?
end

class String
  # A string is blank if it's empty or contains whitespaces only:
  #
  #   ''.blank?                 # => true
  #   '   '.blank?              # => true
  #   '　'.blank?               # => true
  #   ' something here '.blank? # => false
  def blank?
    self !~ /[^[:space:]]/
  end
end

class Numeric #:nodoc:
  # No number is blank:
  #
  #   1.blank? # => false
  #   0.blank? # => false
  def blank?
    false
  end
end
