Create SettingEntry model

app/models/setting_entry.rb

@@ -0,0 +1,52 @@
+class SettingEntry < ApplicationRecord
+  validates :code, presence: true, uniqueness: true
+  validates :value, presence: true
+  validates :format, presence: true
+  validate :valid_value_format
+
+  VALUE_FORMATS = {
+    string: :string_format,
+    integer: :integer_format,
+    boolean: :boolean_format,
+    hash: :hash_format,
+    array: :array_format,
+  }.with_indifferent_access.freeze
+
+  def valid_value_format
+    formats = VALUE_FORMATS.with_indifferent_access
+    errors.add(:format, :invalid) unless formats.keys.any? format
+  end
+
+  def string_format
+    value
+  end
+
+  def integer_format
+    value.to_i
+  end
+
+  def boolean_format
+    value == 'true'
+  end
+
+  def hash_format
+    JSON.parse(value)
+  end
+
+  def array_format
+    JSON.parse(value).to_a
+  end
+
+  def retrieve
+    method = VALUE_FORMATS[format]
+    send(method)
+  end
+
+  def self.method_missing(method, *args)
+    super(method, *args)
+  rescue NoMethodError
+    raise NoMethodError if method.to_s.include? '='
+
+    SettingEntry.find_by!(code: method.to_s).retrieve
+  end
+end