#!/usr/bin/env ruby

require File.expand_path(File.dirname(__FILE__) + '/../test_helper')
require 'xhtmldiff'

class DiffTest < Test::Unit::TestCase

  def setup

  end

  def diff(a,b)
    diff_doc = REXML::Document.new
    diff_doc << (div = REXML::Element.new 'div' )
    hd = XHTMLDiff.new(div)
    parsed_a = REXML::HashableElementDelegator.new(
           REXML::XPath.first(REXML::Document.new("<div>"+a+"</div>"), '/div'))
    parsed_b = REXML::HashableElementDelegator.new(
           REXML::XPath.first(REXML::Document.new("<div>"+b+"</div>"), '/div'))
    Diff::LCS.traverse_balanced(parsed_a, parsed_b, hd)
    diffs = ''
    diff_doc.write(diffs, -1, true, true)
    diffs
  end

  def test_html_diff_simple
    a = 'this was the original string'
    b = 'this is the new string'
    assert_equal("<div><span> this<del class='diffmod'> was</del><ins class='diffmod'> is</ins> the" +
           "<del class='diffmod'> original</del><ins class='diffmod'> new</ins> string</span></div>",
          diff(a, b))
  end

  def test_html_diff_with_multiple_paragraphs
    a = "<p>this was the original string</p>"
    b = "<p>this is</p>\n<p> the new string</p>\n<p>around the world</p>"
    assert_equal(
        "<div><p><span> this<del class='diffmod'> was</del><ins class='diffmod'> is</ins>" +
        "<del class='diffdel'> the</del><del class='diffdel'> original</del><del class='diffdel'> string</del></span></p>" +
        "<ins class='diffins'>\n</ins><ins class='diffins'><p> the new string</p></ins>" +
        "<ins class='diffins'>\n</ins><ins class='diffins'><p>around the world</p></ins></div>",
        diff(a, b))
  end

  def test_html_diff_deleting_a_paragraph
    a = "<p>this is a paragraph</p>\n<p>this is a second paragraph</p>\n<p>this is a third paragraph</p>"
    b = "<p>this is a paragraph</p>\n<p>this is a third paragraph</p>"
    assert_equal(
         "<div><p>this is a paragraph</p>\n<del class='diffdel'><p>this is a second paragraph</p></del>" +
         "<del class='diffdel'>\n</del><p>this is a third paragraph</p></div>",
        diff(a, b))
  end

  def test_split_paragraph_into_two
     a = "<p>foo bar</p>"
     b = "<p>foo</p><p>bar</p>"
     assert_equal(
       "<div><p><span> foo<del class='diffdel'> bar</del></span></p>" +
       "<ins class='diffins'><p>bar</p></ins></div>",
      diff(a,b))
  end

  def test_join_two_paragraphs_into_one
     a = "<p>foo</p><p>bar</p>"
     b = "<p>foo bar</p>"
     assert_equal(
       "<div><p><span> foo<ins class='diffins'> bar</ins></span></p>" +
       "<del class='diffdel'><p>bar</p></del></div>",
      diff(a,b))
  end

  def test_add_inline_element
     a = "<p>foo bar</p>"
     b = "<p>foo <b>bar</b></p>"
     assert_equal(
        "<div><p><span> foo<del class='diffdel'> bar</del></span>" +
        "<ins class='diffins'><b>bar</b></ins></p></div>",
       diff(a,b))
  end

  # FIXME this test fails (ticket #67, http://dev.instiki.org/ticket/67)
  def test_html_diff_preserves_endlines_in_pre
    a = "<pre>a\nb\nc\n</pre>"
    b = "<pre>a\n</pre>"
    assert_equal(
        "<div><pre><span> a\n<del class='diffdel'>b\nc\n</del></span></pre></div>",
        diff(a, b))
  end
  
  def test_html_diff_with_tags
    a = ""
    b = "<div>foo</div>"
    assert_equal "<div><ins class='diffins'><div>foo</div></ins></div>", diff(a, b)
  end
  
  def test_diff_for_tag_change
    a = "<a>x</a>"
    b = "<b>x</b>"
    # FIXME. xhtmldiff fails to detect any change here
    assert_equal "<div><del class='diffdel'><a>x</a></del><ins class='diffins'><b>x</b></ins></div>", diff(a, b)
  end

end