module BigintPk

# File lib/bigint_pk.rb, line 13
def self.enabled= value
  install_patches! if value
end

# File lib/bigint_pk.rb, line 9
def self.setup
  yield self
end

# File lib/bigint_pk.rb, line 22
def self.update_foreign_key table_name, key_name
  update_key table_name, key_name, false
end

# File lib/bigint_pk.rb, line 18
def self.update_primary_key table_name, key_name
  update_key table_name, key_name, true
end

# File lib/bigint_pk.rb, line 46
def self.install_foreign_key_patches!
  [   ActiveRecord::ConnectionAdapters::TableDefinition,
      ActiveRecord::ConnectionAdapters::Table].each do |abstract_table_type|

    abstract_table_type.class_eval do
      def references_with_default_bigint_fk *args
        options = args.extract_options!
        options.reverse_merge! limit: 8
        # Limit shouldn't affect "#{col}_type" column in polymorphic reference.
        # But don't change value if it isn't simple 'true'.
        # Examples:
        #   t.references :subject, null: false, polymorphic: true ==> t.integer :subject_id, limit: 8, null: false
        #                                                             t.string  :subject_type, null: false
        #   t.references :subject, polymorphic: { limit: 120 }    ==> t.integer :subject_id, limit: 8
        #                                                             t.string  :subject_type, limit: 120
        options[:polymorphic] = options.except(:polymorphic, :limit) if options[:polymorphic] == true 
        references_without_default_bigint_fk( *args, options )
      end
      alias_method_chain :references, :default_bigint_fk
      alias_method :belongs_to_without_default_bigint_fk, :belongs_to
      alias_method :belongs_to, :references_with_default_bigint_fk
    end
  end
end

# File lib/bigint_pk.rb, line 28
def self.install_patches!
  install_primary_key_patches!
  install_foreign_key_patches!
end

# File lib/bigint_pk.rb, line 33
def self.install_primary_key_patches!
  ActiveRecord::Base.establish_connection
  ca = ActiveRecord::ConnectionAdapters

  if ca.const_defined? :PostgreSQLAdapter
    ca::PostgreSQLAdapter::NATIVE_DATABASE_TYPES[:primary_key] = 'bigserial primary key'
  end

  if ca.const_defined? :AbstractMysqlAdapter
    ca::AbstractMysqlAdapter::NATIVE_DATABASE_TYPES[:primary_key].gsub! /int\(11\)/, 'bigint(20)'
  end
end

# File lib/bigint_pk.rb, line 72
def self.update_key table_name, key_name, is_primary_key
  c = ActiveRecord::Base.connection
  case c.adapter_name
  when 'PostgreSQL'
    c.execute %Q{
      ALTER TABLE #{c.quote_table_name table_name}
      ALTER COLUMN #{c.quote_column_name key_name}
      TYPE bigint
    }.gsub(/\s+/, ' ').strip
  when /^MySQL/i
    c.execute %Q{
      ALTER TABLE #{c.quote_table_name table_name}
      MODIFY COLUMN #{c.quote_column_name key_name}
      bigint(20) #{is_primary_key ? 'auto_increment' : 'DEFAULT NULL'}
    }.gsub(/\s+/, ' ').strip
  when 'SQLite'
    # noop; sqlite always has 64bit pkeys
  else
    raise "Unsupported adapter '#{c.adapter_name}'"
  end
end

# File lib/bigint_pk.rb, line 51
def references_with_default_bigint_fk *args
  options = args.extract_options!
  options.reverse_merge! limit: 8
  # Limit shouldn't affect "#{col}_type" column in polymorphic reference.
  # But don't change value if it isn't simple 'true'.
  # Examples:
  #   t.references :subject, null: false, polymorphic: true ==> t.integer :subject_id, limit: 8, null: false
  #                                                             t.string  :subject_type, null: false
  #   t.references :subject, polymorphic: { limit: 120 }    ==> t.integer :subject_id, limit: 8
  #                                                             t.string  :subject_type, limit: 120
  options[:polymorphic] = options.except(:polymorphic, :limit) if options[:polymorphic] == true 
  references_without_default_bigint_fk( *args, options )
end