require "test_helper"

class PaginatorTest < ActiveSupport::TestCase

  PER_PAGE = 10

  def setup
    @data = (0..43).to_a
    @pager = Paginator.new(@data.size, PER_PAGE) do |offset,per_page|
      @data[offset,per_page]
    end
  end

  def test_initializing_paginator_raises_exception
    assert_raises(Paginator::MissingSelectError) do
      @pager = Paginator.new(@data.size, PER_PAGE)
    end
  end

  def test_can_get_last_page_from_page_object
    assert_equal @pager.last, @pager.page(2).last
  end

=begin

  # FIXME: Problem with paginator.rb.
  def test_can_get_first_page_from_page_object
    assert_equal @pager.first, @pager.page(2).first
  end

=end

  def test_does_not_exceed_per_page
    @pager.each do |page|
      assert page.items.size <= PER_PAGE
    end
  end

  def test_only_last_page_has_less_items
    @pager.each do |page|
      if page != @pager.last
        assert page.items.size <= PER_PAGE
      else
        assert page.items.size < PER_PAGE
      end
    end
  end

  def test_returns_correct_first_page
    assert_equal @pager.page(1).number, @pager.first.number
  end

  def test_returns_correct_last_page
    assert_equal @pager.page(5).number, @pager.last.number
  end

  def test_last_page_has_no_next_page
    assert !@pager.last.next?
    assert !@pager.last.next
  end

  def test_first_page_has_no_prev_page
    assert !@pager.first.prev?
    assert !@pager.first.prev
  end

  def test_page_enumerable
    @pager.each do |page|
      assert page
      page.each do |item|
        assert item
      end
      page.each_with_index do |item, index|
        assert_equal page.items[index], item
      end
      assert_equal page.items, page.inject([]) { |list, item| list << item }
    end
  end

  def test_each_with_index
    page_offset = 0
    @pager.each_with_index do |page, page_index|
      assert page
      assert_equal page_offset, page_index
      item_offset = 0
      page.each_with_index do |item, item_index|
        assert item
        assert_equal item_offset, item_index
        item_offset += 1
      end
      page_offset += 1
    end
  end

  def test_number_of_pages
    assert_equal 5, @pager.number_of_pages
  end

  def test_passing_block_to_initializer_with_arity_of_two_yields_per_page
    pager = Paginator.new(20,2) do |offset,per_page|
      assert_equal 2, per_page
    end
    pager.page(1).items
  end

  def test_passing_block_to_initializer_with_arity_of_one_does_not_yield_per_page
    pager = Paginator.new(20,2) do |offset|
      assert_equal 0, offset
    end
    pager.page(1).items
  end

  def test_page_object_knows_first_and_last_item_numbers
    items = (1..11).to_a
    pager = Paginator.new(items.size,3) do |offset, per_page|
      items[offset, per_page]
    end
    page = pager.page(1)
    assert_equal 1, page.first_item_number
    assert_equal 3, page.last_item_number
    page = pager.page(2)
    assert_equal 4, page.first_item_number
    assert_equal 6, page.last_item_number
    page = pager.page(3)
    assert_equal 7, page.first_item_number
    assert_equal 9, page.last_item_number
    page = pager.page(4)
    assert_equal 10, page.first_item_number
    assert_equal 11, page.last_item_number
  end

end

class PaginatorTestWithMathN < PaginatorTest

  def setup
    require 'mathn'
    super
  end

end