Module: RichEnums::ClassMethods

Defined in:
lib/rich_enums.rb

Instance Method Summary collapse

Instance Method Details

#rich_enum(column_symbol_value_string_options) ⇒ Object

Raises:



11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
 
# File 'lib/rich_enums.rb', line 11

def rich_enum(column_symbol_value_string_options)
  # rich_enum  column1: { symbol1: [value1, string1], ... }, alt: 'name', **options
  # will transform to
  # 1. enum column1: { symbol1: value1, ...}, to define the enums along with any options provided
  # and
  # 2. Class method "column1_names" that will map the enum values to the full String description
  # and can be accessed by ClassName.<column>_names which will return a hash like { symbol1: string1, symbol2: string2 ...}
  # 3. Class method "column1_alt_name_to_ids" will map the enum values the string values and can
  # be accessed by ClassName.<column>_alt_name_to_ids which will return a hash like { string1: value1, string2: value2 ...}
  # e.g.
  # class Enrollment
  #  include RichEnums
  #  rich_enum learner_payment_path: {
  #     greenfig_online: [10, 'GreenFig Online'],
  #     partner: [20, 'Partner'],
  #     partner_online: [30, 'Partner Online'],
  #     po_check: [40, 'P.O. / Check'],
  #     other: [100, 'Other']
  #   }, _prefix: true
  # end
  # will result in i. enum definitions for learner_payment_path and
  # ii. a class method called learner_payment_path_names
  # Calling learner_payment_path_names returns
  # {"greenfig_online"=>"GreenFig Online", "partner"=>"Partner", "partner_online"=>"Partner Online",
  # "po_check"=>"P.O. / Check", "other"=>"Other"}
  # iii. a class method called learner_payment_path_alt_name_to_ids
  # Calling learner_payment_path_alt_name_to_ids returns
  # {"GreenFig Online"=>10, "Partner"=>20, "Partner Online"=>30, "P.O. / Check"=>40, "Other"=>100}
  # 3. Instance method "column1_name" will return the String associated with the enum value
  # e = Enrollment.new
  # e.learner_payment_path_po_check! -> normal enum method to update the object with enum value
  # e.learner_payment_path      --> :po_check      -> provides the symbol associated with enum value
  # e.learner_payment_path_name --> "P.O. / Check" -> our custom method that returns the string/description
  # TODO: explore if enum options in Array format instead of Hash format will need to be handled

  unless column_symbol_value_string_options.is_a? Hash
    raise RichEnums::Error
  end
  if column_symbol_value_string_options.keys.count.zero?
    raise RichEnums::Error
  end

  # extract out the column
  column = column_symbol_value_string_options.keys.first

  # extract the Enum options for the column which may be in standard enum hash format or our custom format
  symbol_value_string = column_symbol_value_string_options.delete(column)

  raise RichEnums::Error unless symbol_value_string.is_a? Hash

  # at this point, only the enum options like _prefix etc. are present in the original argument
  options = column_symbol_value_string_options
  # we allow for an option called alt: to allow the users to tag the alternate mapping. Defaults to 'alt_name'
  alt = options.delete(:alt).to_s || 'alt_name'
  alt_map_method = 'alt_name_to_ids'

  # create two hashes from the provided input - 1 to be used to define the enum and the other for the name map
  split_hash = symbol_value_string.each_with_object({ for_enum: {}, for_display: {}, for_filter: {} }) do |(symbol, value_string), obj|
    value = value_string.is_a?(Array) ? value_string.first : value_string
    display_string = value_string.is_a?(Array) ? value_string.second : symbol.to_s

    obj[:for_enum][symbol] = value
    obj[:for_display][symbol.to_s] = display_string
    obj[:for_filter][display_string] = value
  end

  # 1. Define the Enum
  if Gem::Version.new(ActiveRecord::VERSION::STRING) >= Gem::Version.new('7.2')
    enum column, split_hash[:for_enum], **options
  else
    enum "#{column}": split_hash[:for_enum], **options
  end

  # 2. Define our custom class methods
  # - the data to be returned by our custom methods is available as a class instance variable
  instance_variable_set("@#{column}_#{alt.pluralize}", split_hash[:for_display])
  instance_variable_set("@#{column}_#{alt_map_method}", split_hash[:for_filter])

  # - the custom methods are just a getter for the class instance variables
  define_singleton_method("#{column}_#{alt.pluralize}") { instance_variable_get("@#{column}_#{alt.pluralize}") }
  define_singleton_method("#{column}_#{alt_map_method}") { instance_variable_get("@#{column}_#{alt_map_method}") }

  # 3. Define our custom instance method to show the String associated with the enum value
  define_method("#{column}_#{alt}") { self.class.send("#{column}_#{alt.pluralize}")[send(column.to_s)] }
end