class DOI

# File lib/libdoi/network.rb, line 49
def data doi
  doi = parse(doi) unless doi.is_a? DOI
  doi.data
end

# File lib/libdoi/network.rb, line 41
def find doi
  doi = parse(doi) unless doi.is_a? DOI
  doi.find
end

# File lib/libdoi.rb, line 62
def parse str
  str = "#{str}"
  if str =~ %r[^https?://(?:(?:dx\.)?doi\.org|doi\.acm\.org|doi\.ieeecomputersociety\.org)/+(?:doi:)?(.*)]i
    # It looks like a HTTP proxy URL.
    doi = CGI.unescape $1
  elsif str =~ %r[^info:doi/(.*)]i
    # It looks like an info URI.
    doi = CGI.unescape $1
  else
    # It's probably a DOI string.
    doi = str.sub %r[^doi:\s*]i, ''
  end

  # ANSI/NISO Z39.84-2005
  # <http://www.niso.org/apps/group_public/download.php/6587/Syntax%20for%20the%20Digital%20Object%20Identifier.pdf>
  if doi =~ %r[^(10)\.([^/]+)/(\p{Graph}(?:[^/]\p{Graph}*)?)$]
    # FIXME: $2 and $3 may contain characters outside of /\p{Graph}/
    new $1, $2, $3
  else
    raise ArgumentError, "'#{str}' is not a valid DOI string";
  end
end

# File lib/libdoi.rb, line 20
def + other
  self.class.new @dir, @reg, @dss + other.to_s
end

# File lib/libdoi.rb, line 27
def << other
  @dss << other.to_s
  self
end

# File lib/libdoi/network.rb, line 27
def data
  uri = URI(_data_url)
  _http_get(uri, 'Accept'=>JSON_Type) do |response|
    return JSON.parse(response.body) if response.code.to_i == 200
  end
  nil
end

# File lib/libdoi/network.rb, line 15
def find
  _http_get(self.to_uri) do |response|
    # FIXME: this is both presumptuous and intolerant
    loc = response['Location']
    return URI(loc) if loc
  end
  nil
end

# File lib/libdoi.rb, line 37
def to_s prefix: true
  (prefix ? 'doi:' : '') + "#{@dir}.#{@reg}/#{@dss}"
end

# File lib/libdoi.rb, line 48
def to_uri info: false
  if info
    URI(_info_uri)
  else
    URI(_http_url)
  end
end

# File lib/libdoi/network.rb, line 74
def _data_url
  CrossRefURL + _uri_path
end

# File lib/libdoi/network.rb, line 61
def _http_get uri, opts={}, &block
  Net::HTTP.start(uri.host, uri.port,
                  :use_ssl=>uri.is_a?(URI::HTTPS),
                 ) do |http|
    query = Net::HTTP::Get.new uri, 'Accept-Encoding'=>''
    query['Connection'] = 'close'
    query['User-Agent'] = UAString
    opts.each_pair {|k,v| query[k] = v }
    http.request query, &block
  end
end

# File lib/libdoi.rb, line 102
def _http_url
  HTTPURI + _uri_path
end

# File lib/libdoi.rb, line 97
def _info_uri
  InfoURI + _uri_path
end

# File lib/libdoi.rb, line 92
def _uri_path
  "#{@dir}.#{CGI.escape @reg}/#{CGI.escape @dss}"
end