Add new functionality for querying, filtering, and sorting changes

lib/bemi.rb

@@ -3,7 +3,9 @@
 class Bemi
 end
 
+require_relative "./bemi/change_query_helpers"
 require_relative "./bemi/context"
 require_relative "./bemi/migration"
 require_relative "./bemi/migration_generator"
+require_relative "./bemi/record_query_helpers"
 require_relative "./bemi/version"

lib/bemi/change_query_helpers.rb

@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require 'active_support/concern'
+
+module Bemi::ChangeQueryHelpers
+  extend ActiveSupport::Concern
+
+  included do
+    scope :before, ->(hash) { where('before @> ?', hash.to_json) }
+    scope :after, ->(hash) { where('after @> ?', hash.to_json) }
+    scope :context, ->(hash) { where('context @> ?', hash.to_json) }
+
+    scope :created, -> { where(operation: 'CREATE') }
+    scope :updated, -> { where(operation: 'UPDATE') }
+    scope :deleted, -> { where(operation: 'DELETE') }
+
+    scope :asc, -> { order(committed_at: :asc) }
+    scope :desc, -> { order(committed_at: :desc) }
+
+    self.filter_attributes = []
+  end
+
+  def diff
+    result = {}
+
+    (before.keys | after.keys).each do |key|
+      next if before[key] == after[key]
+      result[key] = [before[key], after[key]]
+    end
+
+    result
+  end
+end

lib/bemi/record_query_helpers.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require 'active_support/concern'
+
+module Bemi::RecordQueryHelpers
+  extend ActiveSupport::Concern
+
+  class_methods do
+    # Setter
+    def bemi_change_class(bemi_change_class_name)
+      @@bemi_change_class_name = bemi_change_class_name
+    end
+
+    # Getter
+    def __bemi_change_class
+      raise "Please set the change class name with `bemi_change_class 'BemiChange'`" if !@@bemi_change_class_name
+      @@__bemi_change_class ||= @@bemi_change_class_name.constantize
+    end
+  end
+
+  def bemi_changes
+    self.class.__bemi_change_class.where(table: self.class.table_name, primary_key: attributes[self.class.primary_key])
+  end
+end