module Metanorma::Utils

def anchor_or_uuid(node = nil)
  uuid = UUIDTools::UUID.random_create
  node.nil? || node.id.nil? || node.id.empty? ? "_" + uuid : node.id
end

def asciidoc_sub(x)
  return nil if x.nil?
  return "" if x.empty?
  d = Asciidoctor::Document.new(x.lines.entries, { header_footer: false, backend: :html })
  b = d.parse.blocks.first
  b.apply_subs(b.source)
end

def datauri(uri, localdirectory = ".")
  return uri if /^data:/.match(uri)
  path = %r{^([A-Z]:)?/}.match?(uri) ? uri : 
    File.exist?(uri) ? uri : File.join(localdirectory, uri)
  unless File.exist?(path)
    warn "image at #{path} not found"
    return uri
  end
  types = MIME::Types.type_for(path)
  type = types ? types.first.to_s : 'text/plain; charset="utf-8"'
  bin = File.open(path, 'rb', &:read)
  data = Base64.strict_encode64(bin)
  "data:#{type};base64,#{data}"
end

def datauri2mime(uri)
  %r{^data:image/(?<imgtype>[^;]+);base64,(?<imgdata>.+)$} =~ uri
  type = nil
  imgtype = "png" unless /^[a-z0-9]+$/.match imgtype
  ::Tempfile.open(["imageuri", ".#{imgtype}"]) do |file|
    type = datauri2mime1(file, imgdata)
  end
  [type]
end

def datauri2mime1(file, imgdata)
  type = nil
  begin
    file.binmode
    file.write(Base64.strict_decode64(imgdata))
    file.rewind
    type = MimeMagic.by_magic(file)
  ensure
    file.close!
  end
  type
end

def endash_date(elem)
  elem.traverse do |n|
    n.text? and n.replace(n.text.gsub(/\s+--?\s+/, "–").gsub(/--/, "–"))
  end
end

def flatten_rawtext(node)
  result = []
  if node.respond_to?(:blocks) && node.blocks?
    node.blocks.each { |b| result << flatten_rawtext(b) }
  elsif node.respond_to?(:lines)
    result = flatten_rawtext_lines(node, result)
  elsif node.respond_to?(:text)
    result << node.text.gsub(/<[^>]*>+/, "")
  else
    result << node.content.gsub(/<[^>]*>+/, "")
  end
  result.reject(&:empty?)
end

def flatten_rawtext_lines(node, result)
  node.lines.each do |x|
    if node.respond_to?(:context) && (node.context == :literal || node.context == :listing)
      result << x.gsub(/</, "&lt;").gsub(/>/, "&gt;")
    else
      # strip not only HTML <tag>, and Asciidoc xrefs <<xref>>
      result << x.gsub(/<[^>]*>+/, "")
    end
  end
  result
end

def localdir(node)
  docfile = node.attr("docfile")
  docfile.nil? ? './' : Pathname.new(docfile).parent.to_s + '/'
end

def save_dataimage(uri)
  %r{^data:(image|application)/(?<imgtype>[^;]+);base64,(?<imgdata>.+)$} =~ uri
  imgtype.sub!(/\+[a-z0-9]+$/, '') # svg+xml
  imgtype = 'png' unless /^[a-z0-9]+$/.match imgtype
  Tempfile.open(['image', ".#{imgtype}"]) do |f|
    f.binmode
    f.write(Base64.strict_decode64(imgdata))
    f.path
  end
end

def set_nested_value(hash, keys, new_val)
  key = keys[0]
  if keys.length == 1
    hash[key] = hash[key].is_a?(Array) ?  (hash[key] << new_val) :
      hash[key].nil? ?  new_val : [hash[key], new_val]
  else
    if hash[key].is_a?(Array)
      hash[key][-1] = {} if !hash[key].empty? && hash[key][-1].nil?
      hash[key] << {} if hash[key].empty? || !hash[key][-1].is_a?(Hash)
      set_nested_value(hash[key][-1], keys[1..-1], new_val)
    elsif hash[key].nil? || hash[key].empty?
      hash[key] = {}
      set_nested_value(hash[key], keys[1..-1], new_val)
    elsif hash[key].is_a?(Hash) && !hash[key][keys[1]]
      set_nested_value(hash[key], keys[1..-1], new_val)
    elsif !hash[key][keys[1]]
      hash[key] = [hash[key], {}]
      set_nested_value(hash[key][-1], keys[1..-1], new_val)
    else
      set_nested_value(hash[key], keys[1..-1], new_val)
    end
  end
  hash
end

def smartformat(n)
  n.gsub(/ --? /, " — ").
    gsub(/--/, "&#8212;").smart_format.gsub(/</, "&lt;").gsub(/>/, "&gt;")
end

def svgmap_rewrite(xmldoc, localdirectory = "")
  n = Namespace.new(xmldoc)
  xmldoc.xpath(n.ns("//svgmap")).each do |s|
    next unless svgmap_rewrite0(s, n, localdirectory)
    next if s.at(n.ns("./target/eref"))
    s.replace(s.at(n.ns("./figure")))
  end
end

def svgmap_rewrite0(s, n, localdirectory)
  if i = s.at(n.ns(".//image")) and src = i["src"]
    path = /^data:/.match(src) ? save_dataimage(src) : File.file?(src) ? src : localdirectory + src
    File.file?(path) or return false
    svgmap_rewrite1(s, Nokogiri::XML(File.read(path, encoding: "utf-8")), path, n)
    /^data:/.match(src) and i["src"] = datauri(path)
  elsif i = s.at(".//m:svg", "m" => SVG_NS)
    svgmap_rewrite1(s, i, nil, n)
  else
    return false
  end                 
  true
end

def svgmap_rewrite1(s, svg, path, n)
  targets = s.xpath(n.ns("./target")).each_with_object({}) do |t, m|
    x = t.at(n.ns("./xref")) and m[File.expand_path(t["href"])] = "##{x['target']}"
    x = t.at(n.ns("./link")) and m[File.expand_path(t["href"])] = x['target']
    t.remove if t.at(n.ns("./xref | ./link"))
  end
  svg.xpath(".//m:a", "m" => SVG_NS).each do |a|
    a["xlink:href"] and x = targets[File.expand_path(a["xlink:href"])] and a["xlink:href"] = x
    a["href"] and x = targets[File.expand_path(a["href"])] and a["href"] = x
  end
  path and File.open(path, "w", encoding: "utf-8") { |f| f.write(svg.to_xml) }
end

def to_ncname(s)
  start = s[0]
  ret1 = %r([#{NAMECHAR}#]).match(start) ? "_" :
    (%r([#{NAMESTARTCHAR}#]).match(start) ? "_#{start}" : start)
  ret2 = s[1..-1] || ""
  ret = (ret1 || "") + ret2.gsub(%r([#{NAMECHAR}#]), "_")
  ret
end