module Pagy::Backend

def self.included(controller) 

def self.included(controller)
  controller.define_method(:params) { {} } unless controller.method_defined?(:params)
end

def pagy(collection, **vars)

Return Pagy object and paginated results 
def pagy(collection, **vars)
  pagy = Pagy.new(**pagy_get_vars(collection, vars))
  [pagy, pagy_get_items(collection, pagy)]
end

def pagy_get_count(collection, vars)

Get the count from the collection 
def pagy_get_count(collection, vars)
  count_args = vars[:count_args] || DEFAULT[:count_args]
  (count     = collection.count(*count_args)).is_a?(Hash) ? count.size : count
end

def pagy_get_items(collection, pagy)

You may need to override this method for collections without offset|limit
Sub-method called only by #pagy: here for easy customization of fetching by overriding 
def pagy_get_items(collection, pagy)
  collection.offset(pagy.offset).limit(pagy.limit)
end

def pagy_get_limit(vars); end

Override for limit extra 
def pagy_get_limit(vars); end

def pagy_get_page(vars)

Overridable by the jsonapi extra
Get the page integer from the params 
def pagy_get_page(vars)
  params[vars[:page_param] || DEFAULT[:page_param]]
end

def pagy_get_vars(collection, vars)

You may need to override the count call for non AR collections
Sub-method called only by #pagy: here for easy customization of variables by overriding 
def pagy_get_vars(collection, vars)
  vars.tap do |v|
    v[:count] ||= pagy_get_count(collection, v)
    v[:limit] ||= pagy_get_limit(v)
    v[:page]  ||= pagy_get_page(v)
  end
end