require "xml/xslt"
require "nokogiri"

module Omml2Mathml
  module_function
  def convert(filename)
  @tags = %w{
acc
accPr
aln
alnScr
argPr
argSz
bar
barPr
baseJc
begChr
borderBox
borderBoxPr
box
boxPr
brk
brkBin
brkBinSub
cGp
cGpRule
chr
count
cSp
ctrlPr
d
defJc
deg
degHide
den
diff
dispDef
dPr
e
endChr
eqArr
eqArrPr
f
fName
fPr
func
funcPr
groupChr
groupChrPr
grow
hideBot
hideLeft
hideRight
hideTop
interSp
intLim
intraSp
jc
lim
limLoc
limLow
limLowPr
limUpp
limUppPr
lit
lMargin
m
mathFont
mathPr
maxDist
mc
mcJc
mcPr
mcs
mPr
mr
nary
naryLim
naryPr
noBreak
nor
num
objDist
oMath
oMathPara
oMathParaPr
opEmu
phant
phantPr
plcHide
pos
postSp
preSp
r
rad
radPr
rMargin
rPr
rSp
rSpRule
scr
sepChr
show
shp
smallFrac
sPre
sPrePr
sSub
sSubPr
sSubSup
sSubSupPr
sSup
sSupPr
strikeBLTR
strikeH
strikeTLBR
strikeV
sty
sub
subHide
sup
supHide
t
transp
type
vertJc
wrapIndent
wrapRight
zeroAsc
zeroDesc
zeroWid
  }

  @mathml = {}
  @tags.each do |t| 
    @mathml["m_#{t.downcase}"] = "m:#{t}" 
  end

    html = Nokogiri::HTML.parse(File.read(filename, encoding: "utf-8").
                                gsub(/\r/, "").gsub(/<m:/, "<m_").
                                gsub(/<\/m:/, "</m_").
                                gsub(/<!\[if !msEquation\]>/,
                                     "<!--if !msEquation-->"))
    @xslt = XML::XSLT.new
    @xslt.xsl = File.join(File.dirname(__FILE__), "xhtml-mathml.xsl")
    html.traverse do |n|
      if n.comment?
        if /^\[if gte msEquation 12\]>/.match? n.text 
          n.replace(n.text.sub(/\[if gte msEquation 12\]>/, "").
                    sub(/<!\[endif\]/, ""))
        elsif /^if !msEquation/.match? n.text
          n.next.remove
          n.remove
        else
          n.remove
        end
      end
    end
    xml = Nokogiri::XML(html.to_xhtml)
    xml.traverse do |t|
      if t.element? && @mathml.has_key?(t.name)
        t.name = @mathml[t.name]
      end
    end
    #xml.xpath("//xmlns:link | //xmlns:style | //*[@class = 'MsoToc1'] | //*[@class = 'MsoToc2'] |//*[@class = 'MsoToc3'] |//*[@class = 'MsoToc4'] |//*[@class = 'MsoToc5'] |//*[@class = 'MsoToc6'] |//*[@class = 'MsoToc7'] |//*[@class = 'MsoToc8'] |//*[@class = 'MsoToc9'] ").each { |x| x.remove }
    xml.xpath("//*").each do |x|
      if x.name == "m:oMath" || x.name == "m:oMathPara"
        @xslt.xml = x.to_xml.
          sub(/<m:(oMath|oMathPara)>/,
              "<m:\\1 xmlns:m='http://schemas.openxmlformats.org/officeDocument/2006/math'>")
        out = @xslt.serve
        mml = out.gsub(/<\?xml[^>]+>/, '').
          gsub(%r{<([^:/! >]+ xmlns="http://www.w3.org/1998/Math/MathML")},
               "<mml:\\1").
          gsub(%r{<([^:/!>]+)>}, "<mml:\\1>").
          gsub(%r{</([^:/!>]+)>}, "</mml:\\1>").
          gsub(%r{ xmlns="http://www.w3.org/1998/Math/MathML"}, "").
          gsub(%r{ xmlns:mml="http://www.w3.org/1998/Math/MathML"}, "").
          gsub(%r{ xmlns:w="http://schemas.openxmlformats.org/wordprocessingml/2006/main"}, "").
          gsub(%r{ xmlns:m="http://schemas.openxmlformats.org/officeDocument/2006/math"}, "")
        x.replace("<mml:math>#{mml}</mml:math>")
      end
    end
    xml.to_s
  end
end