module Avv2word
  class Document
    include XSLTHelper

    class << self
      include TemplatesHelper

      def extract_images_html(html)
        require "base64"
        require "fileutils"

        # create working dir
        FileUtils.mkdir_p("tmp_imgs")
        resize = 1 # future feature; half size: 0.5

        doc = Nokogiri::HTML.fragment(html)
        doc.css("img").each_with_index do |img_elm,i|
          mime_type, img_data = img_elm.attributes["src"].value.split(",")
          # ^--data:image/jpeg;base64
          ext = mime_type.match(/image\/(\w+?);base64/)[1]
          img_path = "tmp_imgs/image#{i+1}.#{ext}"
          File.open(img_path,"wb"){|f| f.write Base64.decode64(img_data)}
          img_elm.attributes["src"].value = img_path

          match_dimensions = %x( identify #{img_path} ).match(/(?<x>\d+)x(?<y>\d+)/)
          if match_dimensions
            img_elm["style"] = "width:#{match_dimensions[:x].to_i*resize}px;height:#{match_dimensions[:y].to_i*resize}px"
          else
            img_elm["style"] = "width:100px;height:100px"
          end
          # img_elm["style"] = "width:100.5px;height:100.5px"
          # alt: style="width:350px;height:150px"
          # alt: img_elm["data-width"] = "236px"
        end
        doc.to_html
      end

      def escape_footnotes(html)
        doc = Nokogiri::HTML.fragment(html)
        nodes_with_footnotes = doc.css("footnote")
        nodes_with_footnotes.each do |node|
          node.name = "footnote"
          node.content = node.attributes["data-value"]
          node.attributes.map{|k,v| node.attributes[k].remove }
        end
        doc.to_html
      end

      def create(content, template_name = nil, extras = false)
        content = extract_images_html(content)
        content = escape_footnotes(content)
        template_name += extension if template_name && !template_name.end_with?(extension)
        document = new(template_file(template_name))
        document.replace_files(content, extras)
        document.generate
      end

      def create_and_save(content, file_path, template_name = nil, extras = false)
        File.open(file_path, 'wb') do |out|
          out << create(content, template_name, extras)
        end
      end

      def create_with_content(template, content, extras = false)
        content = extract_images_html(content)
        template += extension unless template.end_with?(extension)
        document = new(template_file(template))
        document.replace_files(content, extras)
        document.generate
      end

      def extension
        '.docx'
      end

      def doc_xml_file
        'word/document.xml'
      end

      def numbering_xml_file
        'word/numbering.xml'
      end

      def relations_xml_file
        'word/_rels/document.xml.rels'
      end

      def footer_xml_file
        'word/footer.xml'
      end

      def header_xml_file
        'word/header.xml'
      end

      def content_types_xml_file
        '[Content_Types].xml'
      end

      def footnotes_xml_file
        'word/footnotes.xml'
      end
    end

    def initialize(template_path)
      @replaceable_files = {}
      @template_path = template_path
      @image_files = []
    end

    #
    # Generate a string representing the contents of a docx file.
    #
    def generate
      Zip::File.open(@template_path) do |template_zip|
        buffer = Zip::OutputStream.write_buffer do |out|
          template_zip.each do |entry|
            next if entry.name =~ /\/$/
            out.put_next_entry entry.name
            if @replaceable_files[entry.name] && entry.name == Document.doc_xml_file
              source = entry.get_input_stream.read
              # Change only the body of document. TODO: Improve this...
              source = source.sub(/(<w:body>)((.|\n)*?)(<w:sectPr)/, "\\1#{@replaceable_files[entry.name]}\\4")
              # add header and footer only if they really exist
              if entry.name == 'word/document.xml'
                source.sub!('<!--<w:headerReference w:type="default" r:id="rId8"/>-->','<w:headerReference w:type="default" r:id="rId8"/>') if @header
                source.sub!('<!--<w:footerReference w:type="default" r:id="rId9"/>-->','<w:footerReference w:type="default" r:id="rId9"/>') if @footer
              end
              out.write(source)
            elsif @replaceable_files[entry.name]
              out.write(@replaceable_files[entry.name])
            elsif entry.name == Document.content_types_xml_file
              raw_file = entry.get_input_stream.read
              content_types = @image_files.empty? ? raw_file : inject_image_content_types(raw_file)
              out.write(content_types)
            else
              out.write(template_zip.read(entry.name))
            end
          end
          unless @image_files.empty?
          #stream the image files into the media folder using open-uri
            @image_files.each do |hash|
              out.put_next_entry("word/media/#{hash[:filename]}")
              open(hash[:url], 'rb') do |f|
                out.write(f.read)
              end
            end
          end

          %w( word/_rels/header.xml.rels
              word/_rels/footer.xml.rels
          ).each do |f|
            if @replaceable_files[f]
              out.put_next_entry f
              out.write(@replaceable_files[f])
            end
          end

        end
        buffer.string
      end
    end

    def replace_files(html, extras = false)
      html = '<body></body>' if html.nil? || html.empty?

      header_html = (html =~ /(<header>.*?<\/header>)/m ? $1 : '')
      footer_html = (html =~ /(<footer>.*?<\/footer>)/m ? $1 : '')
      original_source = Nokogiri::HTML(html.gsub(/>[\t\n\r\f]+</, '><')) # whitespace characters without space; nokogiri changes &nbsp; to \u00a0
      header = Nokogiri::HTML(header_html.gsub(/>\s+</, '><'))
      footer = Nokogiri::HTML(footer_html.gsub(/>\s+</, '><'))
      @header = (header_html.empty? ? false : true)
      @footer = (footer_html.empty? ? false : true)
      transform_and_replace(header, xslt_path('header'), Document.header_xml_file)
      transform_and_replace(footer, xslt_path('footer'), Document.footer_xml_file)
      transform_and_replace(original_source, xslt_path('relations'), Document.relations_xml_file)
      source = xslt(stylesheet_name: 'cleanup').transform(original_source)

      transform_and_replace(source, xslt_path('numbering'), Document.numbering_xml_file)
      transform_doc_xml(source, extras)

      local_images(source)
      local_images(footer, :footer) if @footer
      local_images(header, :header) if @header
      
      add_footnotes(source.css("footnote").map{ |footnote| footnote.text })
    end

    def transform_doc_xml(source, extras = false)
      transformed_source = xslt(stylesheet_name: 'cleanup').transform(source)
      transformed_source = xslt(stylesheet_name: 'inline_elements').transform(transformed_source)
      transform_and_replace(transformed_source, document_xslt(extras), Document.doc_xml_file, extras)
    end

    private

    def add_footnotes(footnotes)
      if footnotes.empty?
        @replaceable_files["word/footnotes.xml"] = ""
        return
      end
      #text = Zip::File.open("templates/default.docx"){|zipfile| zipfile.read("word/footnotes.xml")}
      text = "<?xml version=\"1.0\" encoding=\"UTF-8\"?><w:footnotes xmlns:wpc=\"http://schemas.microsoft.com/office/word/2010/wordprocessingCanvas\" xmlns:cx=\"http://schemas.microsoft.com/office/drawing/2014/chartex\" xmlns:cx1=\"http://schemas.microsoft.com/office/drawing/2015/9/8/chartex\" xmlns:cx2=\"http://schemas.microsoft.com/office/drawing/2015/10/21/chartex\" xmlns:cx3=\"http://schemas.microsoft.com/office/drawing/2016/5/9/chartex\" xmlns:cx4=\"http://schemas.microsoft.com/office/drawing/2016/5/10/chartex\" xmlns:cx5=\"http://schemas.microsoft.com/office/drawing/2016/5/11/chartex\" xmlns:cx6=\"http://schemas.microsoft.com/office/drawing/2016/5/12/chartex\" xmlns:cx7=\"http://schemas.microsoft.com/office/drawing/2016/5/13/chartex\" xmlns:cx8=\"http://schemas.microsoft.com/office/drawing/2016/5/14/chartex\" xmlns:mc=\"http://schemas.openxmlformats.org/markup-compatibility/2006\" xmlns:aink=\"http://schemas.microsoft.com/office/drawing/2016/ink\" xmlns:am3d=\"http://schemas.microsoft.com/office/drawing/2017/model3d\" xmlns:o=\"urn:schemas-microsoft-com:office:office\" xmlns:r=\"http://schemas.openxmlformats.org/officeDocument/2006/relationships\" xmlns:m=\"http://schemas.openxmlformats.org/officeDocument/2006/math\" xmlns:v=\"urn:schemas-microsoft-com:vml\" xmlns:wp14=\"http://schemas.microsoft.com/office/word/2010/wordprocessingDrawing\" xmlns:wp=\"http://schemas.openxmlformats.org/drawingml/2006/wordprocessingDrawing\" xmlns:w10=\"urn:schemas-microsoft-com:office:word\" xmlns:w=\"http://schemas.openxmlformats.org/wordprocessingml/2006/main\" xmlns:w14=\"http://schemas.microsoft.com/office/word/2010/wordml\" xmlns:w15=\"http://schemas.microsoft.com/office/word/2012/wordml\" xmlns:w16cid=\"http://schemas.microsoft.com/office/word/2016/wordml/cid\" xmlns:w16se=\"http://schemas.microsoft.com/office/word/2015/wordml/symex\" xmlns:wpg=\"http://schemas.microsoft.com/office/word/2010/wordprocessingGroup\" xmlns:wpi=\"http://schemas.microsoft.com/office/word/2010/wordprocessingInk\" xmlns:wne=\"http://schemas.microsoft.com/office/word/2006/wordml\" xmlns:wps=\"http://schemas.microsoft.com/office/word/2010/wordprocessingShape\" mc:Ignorable=\"w14 w15 w16se w16cid wp14\"><w:footnote w:type=\"separator\" w:id=\"-1\"><w:p w:rsidR=\"00C3170C\" w:rsidRDefault=\"00C3170C\" w:rsidP=\"001755D5\"><w:r><w:separator/></w:r></w:p></w:footnote><w:footnote w:type=\"continuationSeparator\" w:id=\"0\"><w:p w:rsidR=\"00C3170C\" w:rsidRDefault=\"00C3170C\" w:rsidP=\"001755D5\"><w:r><w:continuationSeparator/></w:r></w:p></w:footnote><w:footnote w:id=\"1\"><w:p w:rsidR=\"001755D5\" w:rsidRDefault=\"001755D5\"><w:pPr><w:pStyle w:val=\"FootnoteText\"/></w:pPr><w:r><w:rPr><w:rStyle w:val=\"FootnoteReference\"/></w:rPr><w:footnoteRef/></w:r><w:r><w:t xml:space=\"preserve\"> How are you?</w:t></w:r></w:p></w:footnote></w:footnotes>"
      doc = Nokogiri::XML.parse( text )
      fn_node = doc.xpath("//w:footnote").last
      footnotes.each_with_index do |footnote,i|
        fn_node2 = fn_node.clone
        fn_node2.parent = fn_node.parent
        fn_node2["w:id"] = (fn_node["w:id"].to_i + i).to_s
        fn_node2.xpath("w:p/w:r/w:t").first.content = " " + footnote
      end
      fn_node.remove
      @replaceable_files["word/footnotes.xml"] = doc.to_xml

      # add relation
      rels = Nokogiri::XML(@replaceable_files["word/_rels/document.xml.rels"])
      [ #'<Relationship Id="rIdXX" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/endnotes" Target="endnotes.xml"/>',
      '<Relationship Id="rIdXX" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/footnotes" Target="footnotes.xml"/>'
      ].each do |new_rel|
        new_rel.sub!(/XX/, (rels.xpath("//xmlns:Relationship").size+1).to_s )
        rels.children.first << Nokogiri::XML.parse(new_rel).child
      end
      @replaceable_files["word/_rels/document.xml.rels"] = rels.to_xml

      # settings
      if @replaceable_files["word/settings.xml"]
        sets = Nokogiri::XML(@replaceable_files["word/settings.xml"])
      else
        sets = nil
        Zip::File.open(@template_path) do |zipfile|
          sets = Nokogiri::XML.parse(zipfile.read("word/settings.xml"))
        end
      end
      ['<w:footnotePr><w:footnote w:id="-1"/><w:footnote w:id="0"/></w:footnotePr>',
      #'<w:endnotePr><w:endnote w:id="-1"/><w:endnote w:id="0"/></w:endnotePr>'
      ].each do |new_type|
        sets.children.first << Nokogiri::XML.parse(new_type).child
      end
      @replaceable_files["word/settings.xml"] = sets.to_xml

      # styles
      if @replaceable_files["word/styles.xml"]
        styles = Nokogiri::XML(@replaceable_files["word/styles.xml"])
      else
        styles = nil
        Zip::File.open(@template_path) do |zipfile|
          styles = Nokogiri::XML.parse(zipfile.read("word/styles.xml"))
        end
      end
      [ '<w:style w:type="paragraph" w:styleId="FootnoteText"><w:name w:val="footnote text"/><w:basedOn w:val="Normal"/><w:link w:val="FootnoteTextChar"/><w:uiPriority w:val="99"/><w:semiHidden/><w:unhideWhenUsed/><w:rsid w:val="008D12FB"/></w:style>',
        '<w:style w:type="character" w:customStyle="1" w:styleId="FootnoteTextChar"><w:name w:val="Footnote Text Char"/><w:basedOn w:val="DefaultParagraphFont"/><w:link w:val="FootnoteText"/><w:uiPriority w:val="99"/><w:semiHidden/><w:rsid w:val="008D12FB"/></w:style>',
        '<w:style w:type="character" w:styleId="FootnoteReference"><w:name w:val="footnote reference"/><w:basedOn w:val="DefaultParagraphFont"/><w:uiPriority w:val="99"/><w:semiHidden/><w:unhideWhenUsed/><w:rsid w:val="008D12FB"/><w:rPr><w:vertAlign w:val="superscript"/></w:rPr></w:style>'
      ].each do |new_style|
        styles.children.first << Nokogiri::XML.parse(new_style).child
      end
      [ '<w:lsdException w:name="footnote text" w:semiHidden="1" w:unhideWhenUsed="1"/>',
        '<w:lsdException w:name="footnote reference" w:semiHidden="1" w:unhideWhenUsed="1"/>'
      ].each do |new_latent_style|
        styles.xpath("/w:styles/w:latentStyles").first << Nokogiri::XML.parse(new_latent_style).child
      end
      @replaceable_files["word/styles.xml"] = styles.to_xml

      # content type
      Zip::File.open(@template_path) do |zipfile|
        types = Nokogiri::XML.parse(zipfile.read("[Content_Types].xml"))
        [ # '<Override PartName="/word/endnotes.xml" ContentType="application/vnd.openxmlformats-officedocument.wordprocessingml.endnotes+xml"/>',
        '<Override PartName="/word/footnotes.xml" ContentType="application/vnd.openxmlformats-officedocument.wordprocessingml.footnotes+xml"/>'
        ].each do |new_type|
          types.children.first << Nokogiri::XML.parse(new_type).child
        end
        @replaceable_files["[Content_Types].xml"] = types.to_xml
      end
    end

    def inject_relations(relations, noko_html_source)
      rel_doc = Nokogiri::XML(relations)
      relations_root = rel_doc.css("Relationships").first
      relations_size = relations_root.css("Relationship").size
      img_counter = 0

      html = noko_html_source.to_xml
      html.scan(/<img.*?>|<a.*?\/a>/).each_with_index do |link,i|
        new_relation = relations_root.css("Relationship").last.clone

        case link
        when /^<a/
          a_href = link.match(/href="(.*?)"/)[1]
          new_relation["Id"] = "rId#{i + 1 + relations_size}"
          new_relation["Type"] = "http://schemas.openxmlformats.org/officeDocument/2006/relationships/hyperlink"
          new_relation["TargetMode"] = "External"
          new_relation["Target"] = a_href
        when /^<img/
          img_counter += 1
          img_src = link.match(/src="(.*?)"/)[1]
          new_relation["Id"] = "rId#{i + 1 + relations_size}"
          new_relation["Type"] = "http://schemas.openxmlformats.org/officeDocument/2006/relationships/image"
          new_relation["Target"] = "media/image#{img_counter}#{File.extname(img_src)}"
          new_relation.remove_attribute("TargetMode") if new_relation["TargetMode"]
        end
        relations_root.add_child new_relation
      end

      rel_doc.to_xml
    end

    def transform_and_replace(source, stylesheet_path, file, remove_ns = false)
      stylesheet = xslt(stylesheet_path: stylesheet_path)
      content = stylesheet.apply_to(source)
      content.gsub!(/\s*xmlns:(\w+)="(.*?)\s*"/, '') if remove_ns

      if ( file =~ /document\.xml\.rels/ ) && (( source.css("a").size > 0 ) || ( source.css("img").size > 0 ))
        content = inject_relations(content, source)
      elsif file =~ /header/i
        @replaceable_files["word/_rels/header.xml.rels"] = %(<?xml version="1.0" encoding="UTF-8"?>\n<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">\n</Relationships>)
        source.css("img").each_with_index do |noko_img,i|
          # <Relationship Id="rId1" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/image" Target="media/image3.png"/>
          new_head_rel = %Q(<Relationship Id="rId#{i+10}" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/image" Target="media/#{File.basename(noko_img["src"])}"/>)
          @replaceable_files["word/_rels/header.xml.rels"].sub!(/<\/Relationships>/, new_head_rel + "</Relationships>")
        end
      elsif file =~ /footer/i
        @replaceable_files["word/_rels/footer.xml.rels"] = %(<?xml version="1.0" encoding="UTF-8"?>\n<Relationships xmlns="http://schemas.openxmlformats.org/package/2006/relationships">\n</Relationships>)
        source.css("img").each_with_index do |noko_img,i|
          new_foot_rel = %Q(<Relationship Id="rId#{i+10}" Type="http://schemas.openxmlformats.org/officeDocument/2006/relationships/image" Target="media/#{File.basename(noko_img["src"])}"/>)
          @replaceable_files["word/_rels/footer.xml.rels"].sub!(/<\/Relationships>/, new_foot_rel + "</Relationships>")
        end
      end
      @replaceable_files[file] = content
    end

    #generates an array of hashes with filename and full url
    #for all images to be embeded in the word document
    def local_images(source, type = nil)
      source.css('img').sort_by{|e| e.attributes['src'].value}.each_with_index do |image,i|
        filename = image['data-filename'] ? image['data-filename'] : image['src'].split("/").last
        ext = File.extname(filename).delete(".").downcase
        @image_files << { filename: "image#{@image_files.size+1}.#{ext}", url: image['src'], ext: ext }
      end
    end

    #get extension from filename and clean to match content_types
    def content_type_from_extension(ext)
      ext == "jpg" ? "jpeg" : ext
    end

    #inject the required content_types into the [content_types].xml file...
    def inject_image_content_types(source)
      doc = Nokogiri::XML(source)

      #get a list of all extensions currently in content_types file
      existing_exts = doc.css("Default").map { |node| node.attribute("Extension").value }.compact

      #get a list of extensions we need for our images
      required_exts = @image_files.map{ |i| i[:ext] }

      #workout which required extensions are missing from the content_types file
      missing_exts = (required_exts - existing_exts).uniq

      #inject missing extensions into document
      missing_exts.each do |ext|
        doc.at_css("Types").add_child( "<Default Extension='#{ext}' ContentType='image/#{content_type_from_extension(ext)}'/>")
      end

      #return the amended source to be saved into the zip
      doc.to_s
    end
  end
end