require 'uri'

module RackWebDAV
  
  class Controller
    include RackWebDAV::HTTPStatus
    include RackWebDAV::Utils
    
    attr_reader :request, :response, :resource

    # request:: Rack::Request
    # response:: Rack::Response
    # options:: Options hash
    # Create a new Controller.
    # NOTE: options will be passed to Resource
    def initialize(request, response, options={})
      raise Forbidden if request.path_info.include?('..')
      @request = request
      @response = response
      @options = options
      
      @dav_extensions = options.delete(:dav_extensions) || []
      @always_include_dav_header = options.delete(:always_include_dav_header)
      
      @resource = resource_class.new(actual_path, implied_path, @request, @response, @options)
      
      if(@always_include_dav_header)
        add_dav_header
      end
    end
    
    # s:: string
    # Escape URL string
    def url_format(resource)
      ret = URI.escape(resource.public_path)
      if resource.collection? and ret[-1,1] != '/'
        ret += '/'
      end
      ret
    end
    
    # s:: string
    # Unescape URL string
    def url_unescape(s)
      URI.unescape(s)
    end
    
    def add_dav_header
      unless(response['Dav'])
        dav_support = %w(1 2) + @dav_extensions
        response['Dav'] = dav_support.join(', ')
      end
    end
    
    # Return response to OPTIONS
    def options
      add_dav_header
      response['Allow'] = 'OPTIONS,HEAD,GET,PUT,POST,DELETE,PROPFIND,PROPPATCH,MKCOL,COPY,MOVE,LOCK,UNLOCK'
      response['Ms-Author-Via'] = 'DAV'
      OK
    end
    
    # Return response to HEAD
    def head
      if(resource.exist?)
        response['Etag'] = resource.etag
        response['Content-Type'] = resource.content_type
        response['Last-Modified'] = resource.last_modified.httpdate
        OK
      else
        NotFound
      end
    end
    
    # Return response to GET
    def get
      if(resource.exist?)
        res = resource.get(request, response)
        if(res == OK && !resource.collection?)
          response['Etag'] = resource.etag
          response['Content-Type'] = resource.content_type
          response['Content-Length'] = resource.content_length.to_s
          response['Last-Modified'] = resource.last_modified.httpdate
        end
        res
      else
        NotFound
      end
    end

    # Return response to PUT
    def put
      if(resource.collection?)
        Forbidden
      elsif(!resource.parent_exists? || !resource.parent_collection?)
        Conflict
      else
        resource.lock_check if resource.supports_locking?
        status = resource.put(request, response)
        response['Location'] = "#{scheme}://#{host}:#{port}#{url_format(resource)}" if status == Created
        response.body = response['Location']
        status
      end
    end

    # Return response to POST
    def post
      resource.post(request, response)
    end

    # Return response to DELETE
    def delete
      if(resource.exist?)
        resource.lock_check if resource.supports_locking?
        resource.delete
      else
        NotFound
      end
    end
    
    # Return response to MKCOL
    def mkcol
      resource.lock_check if resource.supports_locking?
      status = resource.make_collection
      gen_url = "#{scheme}://#{host}:#{port}#{url_format(resource)}" if status == Created
      if(resource.use_compat_mkcol_response?)
        multistatus do |xml|
          xml.response do
            xml.href gen_url
            xml.status "#{http_version} #{status.status_line}"
          end
        end
      else
        response['Location'] = gen_url
        status
      end
    end
    
    # Return response to COPY
    def copy
      move(:copy)
    end

    # args:: Only argument used: :copy
    # Move Resource to new location. If :copy is provided,
    # Resource will be copied (implementation ease)
    def move(*args)
      unless(resource.exist?)
        NotFound
      else
        resource.lock_check if resource.supports_locking? && !args.include(:copy)
        destination = url_unescape(env['HTTP_DESTINATION'].sub(%r{https?://([^/]+)}, ''))
        dest_host = $1
        if(dest_host && dest_host.gsub(/:\d{2,5}$/, '') != request.host)
          BadGateway
        elsif(destination == resource.public_path)
          Forbidden
        else
          collection = resource.collection?
          dest = resource_class.new(destination, clean_path(destination), @request, @response, @options.merge(:user => resource.user))
          status = nil
          if(args.include?(:copy))
            status = resource.copy(dest, overwrite)
          else
            return Conflict unless depth.is_a?(Symbol) || depth > 1
            status = resource.move(dest, overwrite)
          end
          response['Location'] = "#{scheme}://#{host}:#{port}#{url_format(dest)}" if status == Created
          # RFC 2518
          if collection
            multistatus do |xml|
              xml.response do
                xml.href "#{scheme}://#{host}:#{port}#{url_format(status == Created ? dest : resource)}"
                xml.status "#{http_version} #{status.status_line}"
              end
            end
          else
            status
          end
        end
      end
    end
    
    # Return response to PROPFIND
    def propfind
      unless(resource.exist?)
        NotFound
      else
        unless(request_document.xpath("//#{ns}propfind/#{ns}allprop").empty?)
          properties = resource.properties
        else
          check = request_document.xpath("//#{ns}propfind")
          if(check && !check.empty?)
            properties = request_document.xpath(
              "//#{ns}propfind/#{ns}prop"
            ).children.find_all{ |item|
              item.element?
            }.map{ |item|
              # We should do this, but Nokogiri transforms prefix w/ null href into
              # something valid.  Oops.
              # TODO: Hacky grep fix that's horrible
              hsh = to_element_hash(item)
              if(hsh.namespace.nil? && !ns.empty?)
                raise BadRequest if request_document.to_s.scan(%r{<#{item.name}[^>]+xmlns=""}).empty?
              end
              hsh
            }.compact
          else
            # XXX: Compatibility for Windows.
            # raise BadRequest
            properties = []
          end
        end
        multistatus do |xml|
          find_resources.each do |resource|
            xml.response do
              unless(resource.propstat_relative_path)
                xml.href "#{scheme}://#{host}:#{port}#{url_format(resource)}"
              else
                xml.href url_format(resource)
              end
              propstats(xml, get_properties(resource, properties.empty? ? resource.properties : properties))
            end
          end
        end
      end
    end
    
    # Return response to PROPPATCH
    def proppatch
      unless(resource.exist?)
        NotFound
      else
        resource.lock_check if resource.supports_locking?
        prop_actions = []
        request_document.xpath("/#{ns}propertyupdate").children.each do |element|
          case element.name
          when 'set', 'remove'
            prp = element.children.detect{|e|e.name == 'prop'}
            if(prp)
              prp.children.each do |elm|
                next if elm.name == 'text'
                prop_actions << {:type => element.name, :name => to_element_hash(elm), :value => elm.text}
              end
            end
          end
        end
        multistatus do |xml|
          find_resources.each do |resource|
            xml.response do
              xml.href "#{scheme}://#{host}:#{port}#{url_format(resource)}"
              prop_actions.each do |action|
                case action[:type]
                when 'set'
                  propstats(xml, set_properties(resource, action[:name] => action[:value]))
                when 'remove'
                  rm_properties(resource, action[:name] => action[:value])
                end
              end
            end
          end
        end
      end
    end


    # Lock current resource
    # NOTE: This will pass an argument hash to Resource#lock and
    # wait for a success/failure response. 
    def lock
      lockinfo = request_document.xpath("//#{ns}lockinfo")
      asked = {}
      asked[:timeout] = request.env['Timeout'].split(',').map{|x|x.strip} if request.env['Timeout']
      asked[:depth] = depth
      unless([0, :infinity].include?(asked[:depth]))
        BadRequest
      else
        asked[:scope] = lockinfo.xpath("//#{ns}lockscope").children.find_all{|n|n.element?}.map{|n|n.name}.first
        asked[:type] = lockinfo.xpath("#{ns}locktype").children.find_all{|n|n.element?}.map{|n|n.name}.first
        asked[:owner] = lockinfo.xpath("//#{ns}owner/#{ns}href").children.map{|n|n.text}.first
        begin
          lock_time, locktoken = resource.lock(asked)
          render_xml(:prop) do |xml|
            xml.lockdiscovery do
              xml.activelock do
                if(asked[:scope])
                  xml.lockscope do
                    xml.send(asked[:scope])
                  end
                end
                if(asked[:type])
                  xml.locktype do
                    xml.send(asked[:type])
                  end
                end
                xml.depth asked[:depth].to_s
                xml.timeout lock_time ? "Second-#{lock_time}" : 'infinity'
                xml.locktoken do
                  xml.href locktoken
                end
                if(asked[:owner])
                  xml.owner asked[:owner]
                end
              end
            end
          end
          response.headers['Lock-Token'] = locktoken
          response.status = resource.exist? ? OK : Created
        rescue LockFailure => e
          multistatus do |xml|
            e.path_status.each_pair do |path, status|
              xml.response do
                xml.href path
                xml.status "#{http_version} #{status.status_line}"
              end
            end
          end
        end
      end
    end

    # Unlock current resource
    def unlock
      resource.unlock(lock_token)
    end

    # Perform authentication
    # NOTE: Authentication will only be performed if the Resource
    # has defined an #authenticate method
    def authenticate
      authed = true
      if(resource.respond_to?(:authenticate, true))
        authed = false
        uname = nil
        password = nil
        if(request.env['HTTP_AUTHORIZATION'])
          auth = Rack::Auth::Basic::Request.new(request.env)
          if(auth.basic? && auth.credentials)
            uname = auth.credentials[0]
            password = auth.credentials[1]
          end
        end
        authed = resource.send(:authenticate, uname, password)
      end
      raise Unauthorized unless authed
    end
    
    private

    # Request environment variables
    def env
      @request.env
    end
    
    # Current request scheme (http/https)
    def scheme
      request.scheme
    end
    
    # Request host
    def host
      request.host
    end
    
    # Request port
    def port
      request.port
    end
    
    # Class of the resource in use
    def resource_class
      @options[:resource_class]
    end

    # Root URI path for the resource
    def root_uri_path
      @options[:root_uri_path]
    end
    
    # Returns Resource path with root URI removed
    def implied_path
      clean_path(@request.path.dup)
    end
    
    # x:: request path
    # Unescapes path and removes root URI if applicable
    def clean_path(x)
      ip = url_unescape(x)
      ip.gsub!(/^#{Regexp.escape(root_uri_path)}/, '') if root_uri_path
      ip
    end
    
    # Unescaped request path
    def actual_path
      url_unescape(@request.path.dup)
    end

    # Lock token if provided by client
    def lock_token
      env['HTTP_LOCK_TOKEN'] || nil
    end
    
    # Requested depth
    def depth
      d = env['HTTP_DEPTH']
      if(d =~ /^\d+$/)
        d = d.to_i
      else
        d = :infinity
      end
      d
    end

    # Current HTTP version being used
    def http_version
      env['HTTP_VERSION'] || env['SERVER_PROTOCOL'] || 'HTTP/1.0'
    end
    
    # Overwrite is allowed
    def overwrite
      env['HTTP_OVERWRITE'].to_s.upcase != 'F'
    end

    # Find resources at depth requested
    def find_resources(with_current_resource=true)
      ary = nil
      case depth
      when 0
        ary = []
      when 1
        ary = resource.children
      else
        ary = resource.descendants
      end
      with_current_resource ? [resource] + ary : ary
    end
    
    # XML parsed request
    def request_document
      @request_document ||= Nokogiri.XML(request.body.read)
    rescue
      raise BadRequest
    end

    # Namespace being used within XML document
    # TODO: Make this better
    def ns(wanted_uri="DAV:")
      _ns = ''
      if(request_document && request_document.root && request_document.root.namespace_definitions.size > 0)
        _ns = request_document.root.namespace_definitions.collect{|__ns| __ns if __ns.href == wanted_uri}.compact
        if _ns.empty?
          _ns = request_document.root.namespace_definitions.first.prefix.to_s if _ns.empty?
        else
          _ns = _ns.first
          _ns = _ns.prefix.nil? ? 'xmlns' : _ns.prefix.to_s
        end
        _ns += ':' unless _ns.empty?
      end
      _ns
    end
    
    # root_type:: Root tag name
    # Render XML and set Rack::Response#body= to final XML
    def render_xml(root_type)
      raise ArgumentError.new 'Expecting block' unless block_given?
      doc = Nokogiri::XML::Builder.new do |xml_base|
        xml_base.send(root_type.to_s, {'xmlns:D' => 'DAV:'}.merge(resource.root_xml_attributes)) do
          xml_base.parent.namespace = xml_base.parent.namespace_definitions.first
          xml = xml_base['D']
          yield xml
        end
      end
     
      if(@options[:pretty_xml])
        response.body = doc.to_xml
      else
        response.body = doc.to_xml(
          :save_with => Nokogiri::XML::Node::SaveOptions::AS_XML
        )
      end
      response["Content-Type"] = 'text/xml; charset="utf-8"'
      response["Content-Length"] = response.body.size.to_s
    end
      
    # block:: block
    # Creates a multistatus response using #render_xml and
    # returns the correct status
    def multistatus(&block)
      render_xml(:multistatus, &block)
      MultiStatus
    end
    
    # xml:: Nokogiri::XML::Builder
    # errors:: Array of errors
    # Crafts responses for errors
    def response_errors(xml, errors)
      for path, status in errors
        xml.response do
          xml.href "#{scheme}://#{host}:#{port}#{URI.escape(path)}"
          xml.status "#{http_version} #{status.status_line}"
        end
      end
    end

    # resource:: Resource
    # elements:: Property hashes (name, ns_href, children)
    # Returns array of property values for given names
    def get_properties(resource, elements)
      stats = Hash.new { |h, k| h[k] = [] }
      for element in elements
        begin
          val = resource.get_property(element)
          stats[OK] << [element, val]
        rescue Unauthorized => u
          raise u
        rescue Status
          stats[$!.class] << element
        end
      end
      stats
    end

    # resource:: Resource
    # elements:: Property hashes (name, namespace, children)
    # Removes the given properties from a resource
    def rm_properties(resource, elements)
      for element, value in elements
        resource.remove_property(element)
      end
    end

    # resource:: Resource
    # elements:: Property hashes (name, namespace, children)
    # Sets the given properties
    def set_properties(resource, elements)
      stats = Hash.new { |h, k| h[k] = [] }
      for element, value in elements
        begin
          stats[OK] << [element, resource.set_property(element, value)]
        rescue Unauthorized => u
          raise u
        rescue Status
          stats[$!.class] << element
        end
      end
      stats
    end
    
    # xml:: Nokogiri::XML::Builder
    # stats:: Array of stats
    # Build propstats response
    def propstats(xml, stats)
      return if stats.empty?
      for status, props in stats
        xml.propstat do
          xml.prop do
            for element, value in props
              defn = xml.doc.root.namespace_definitions.find{|ns_def| ns_def.href == element[:ns_href]}
              if defn.nil?
                if element[:ns_href] and not element[:ns_href].empty?
                  _ns = "unknown#{rand(65536)}"
                  xml.doc.root.add_namespace_definition(_ns, element[:ns_href])
                else
                  _ns = nil
                end
              else
                # Unfortunately Nokogiri won't let the null href, non-null prefix happen
                # So we can't properly handle that error.
                _ns = element[:ns_href].nil? ? nil : defn.prefix
              end
              ns_xml = _ns.nil? ? xml : xml[_ns]
              if (value.is_a?(Nokogiri::XML::Node)) or (value.is_a?(Nokogiri::XML::DocumentFragment))
                xml.__send__ :insert, value
              elsif(value.is_a?(Symbol))
                ns_xml.send(element[:name]) do
                  ns_xml.send(value)
                end
              else
                ns_xml.send(element[:name], value) do |x|
                  # Make sure we return valid XML
                  x.parent.namespace = nil if _ns.nil?
                end
              end

              # This is gross, but make sure we set the current namespace back to DAV:
              xml['D']
            end
          end
          xml.status "#{http_version} #{status.status_line}"
        end
      end
    end
    
    # xml:: Nokogiri::XML::Builder
    # element:: Nokogiri::XML::Element
    # Converts element into proper text
    def xml_convert(xml, element)
      xml.doc.root.add_child(element)
    end

  end

end