# frozen_string_literal: true

require 'watirspec_helper'

module Watir
  describe Scrolling do
    before do
      browser.goto(WatirSpec.url_for('scroll.html'))
      pause
    end

    def top_centered_viewport
      browser.execute_script('return (window.innerHeight - document.body.scrollHeight)/2;')
    end

    def current_top
      browser.execute_script('return document.body.getBoundingClientRect().top;')
    end

    context 'when scrolling Browser' do
      describe '#to' do
        it 'scrolls to the top of the page' do
          browser.scroll.to :bottom
          expect(browser.div(id: 'top')).not_to be_in_viewport
          browser.scroll.to :top
          expect(browser.div(id: 'top')).to be_in_viewport
        end

        it 'scrolls to the center of the page' do
          browser.scroll.to :center
          viewport_top = browser.execute_script('return document.body.getBoundingClientRect().top;')

          expect(viewport_top).to be_within(1).of(top_centered_viewport)
        end

        it 'scrolls to the bottom of the page' do
          expect(browser.div(id: 'bottom')).not_to be_in_viewport
          browser.scroll.to :bottom
          expect(browser.div(id: 'bottom')).to be_in_viewport
        end

        it 'scrolls to coordinates' do
          element = browser.div(id: 'center')
          location = element.location
          browser.scroll.to [location.x, location.y]
          expect(element).to be_in_viewport
        end

        it 'raises error when scroll point is not valid' do
          expect { browser.scroll.to(:blah) }.to raise_error(ArgumentError)
        end
      end

      describe '#by' do
        before do
          browser.scroll.to :top
          pause
        end

        it 'offset from top' do
          initial_top = current_top
          scroll_by = top_centered_viewport.round
          browser.scroll.by(0, -scroll_by)
          pause
          puts "scroll by #{scroll_by}"
          puts "initial top #{initial_top}"
          puts "current top #{current_top}"
          expect(current_top).to be_within(1).of(scroll_by + initial_top)
        end

        it 'offset from bottom' do
          initial_top = current_top
          browser.scroll.to :bottom
          scroll_by = top_centered_viewport
          browser.scroll.by(0, scroll_by)
          pause
          expect(current_top).to be_within(1).of(scroll_by + initial_top)
        end
      end

      describe '#from' do
        it 'scrolls by given amount with offset', except: {browser: :ie, reason: 'Not implemented'} do
          browser.goto(WatirSpec.url_for('scroll_nested.html'))

          browser.scroll.from(10, 10).by(0, 225)

          expect(in_viewport?(browser.iframe.checkbox(name: 'scroll_checkbox'))).to be true
        end
      end
    end

    context 'when scrolling Element' do
      describe '#to' do
        it 'scrolls element into view (viewport)',
           except: [{browser: %i[firefox safari], reason: 'incorrect MoveTargetOutOfBoundsError'},
                    {browser: :ie, reason: 'Not implemented'}] do
          browser.goto(WatirSpec.url_for('scroll_nested_offscreen.html'))
          iframe = browser.iframe

          expect(in_viewport?(iframe)).to be false

          iframe.scroll.to(:viewport)

          expect(in_viewport?(iframe)).to be true
        end

        it 'scrolls to element (top) by default' do
          element = browser.div(id: 'center')
          element.scroll.to

          element_top = browser.execute_script('return arguments[0].getBoundingClientRect().top', element)
          expect(element_top).to be_within(1).of(0)
        end

        it 'scrolls to element (center)' do
          element = browser.div(id: 'center')
          element.scroll.to :center

          element_rect = browser.execute_script('return arguments[0].getBoundingClientRect()', element)

          expect(element_rect['top']).to eq(element_rect['bottom'] - element_rect['height'])
        end

        it 'scrolls to element (bottom)' do
          element = browser.div(id: 'center')
          element.scroll.to :bottom

          element_bottom = browser.execute_script('return arguments[0].getBoundingClientRect().bottom', element)
          window_height = browser.execute_script('return window.innerHeight')

          expect(element_bottom).to be_within(1).of(window_height)
        end

        it 'scrolls to element multiple times' do
          2.times do
            element = browser.div(id: 'center')
            element.scroll.to(:center)

            element_rect = browser.execute_script('return arguments[0].getBoundingClientRect()', element)

            expect(element_rect['top']).to eq(element_rect['bottom'] - element_rect['height'])
          end
        end

        it 'raises error when scroll param is not valid' do
          expect { browser.div(id: 'top').scroll.to(:blah) }.to raise_error(ArgumentError)
        end
      end

      describe '#by' do
        it 'offset' do
          browser.scroll.to :top
          pause
          initial_top = current_top
          browser.scroll.to :bottom
          pause
          scroll_by = top_centered_viewport

          element = browser.div(id: 'bottom')
          element.scroll.by(0, scroll_by)
          pause
          expect(current_top).to be_within(1).of(scroll_by + initial_top)
        end
      end

      describe '#from',
               except: [{browser: %i[firefox safari], reason: 'incorrect MoveTargetOutOfBoundsError'},
                        {browser: :ie, reason: 'Not implemented'}] do
        it 'scrolls from element by given amount' do
          browser.goto(WatirSpec.url_for('scroll_nested_offscreen.html'))
          iframe = browser.iframe

          iframe.scroll.from.by(0, 200)

          checkbox = iframe.checkbox(name: 'scroll_checkbox')
          expect(in_viewport?(checkbox)).to be true
        end

        it 'scrolls from an element with an offset' do
          browser.goto(WatirSpec.url_for('scroll_nested_offscreen.html'))

          move_left = browser.execute_script('return arguments[0].getBoundingClientRect().width/2', browser.footer) -
                      browser.execute_script('return arguments[0].getBoundingClientRect().right/2', browser.iframe.we)

          browser.footer.scroll.from(-move_left.round, -50).by(0, 200)

          checkbox = browser.iframe.checkbox(name: 'scroll_checkbox')
          expect(in_viewport?(checkbox)).to be true
        end
      end
    end

    def in_viewport?(element)
      in_viewport = <<~IN_VIEWPORT
        for(var e=arguments[0],f=e.offsetTop,t=e.offsetLeft,o=e.offsetWidth,n=e.offsetHeight;
        e.offsetParent;)f+=(e=e.offsetParent).offsetTop,t+=e.offsetLeft;
        return f<window.pageYOffset+window.innerHeight&&t<window.pageXOffset+window.innerWidth&&f+n>
        window.pageYOffset&&t+o>window.pageXOffset
      IN_VIEWPORT

      element.browser.execute_script(in_viewport, element.we)
    end

    def pause
      sleep 0.2
    end
  end
end