# frozen_string_literal: true

require_relative 'constants'
require_relative 'utils'
require_relative 'media_type'

module Rack
  # Rack::Request provides a convenient interface to a Rack
  # environment.  It is stateless, the environment +env+ passed to the
  # constructor will be directly modified.
  #
  #   req = Rack::Request.new(env)
  #   req.post?
  #   req.params["data"]

  class Request
    class << self
      attr_accessor :ip_filter

      # The priority when checking forwarded headers. The default
      # is <tt>[:forwarded, :x_forwarded]</tt>, which means, check the
      # +Forwarded+ header first, followed by the appropriate
      # <tt>X-Forwarded-*</tt> header.  You can revert the priority by
      # reversing the priority, or remove checking of either
      # or both headers by removing elements from the array.
      #
      # This should be set as appropriate in your environment
      # based on what reverse proxies are in use.  If you are not
      # using reverse proxies, you should probably use an empty
      # array.
      attr_accessor :forwarded_priority

      # The priority when checking either the <tt>X-Forwarded-Proto</tt>
      # or <tt>X-Forwarded-Scheme</tt> header for the forwarded protocol.
      # The default is <tt>[:proto, :scheme]</tt>, to try the
      # <tt>X-Forwarded-Proto</tt> header before the
      # <tt>X-Forwarded-Scheme</tt> header.  Rack 2 had behavior
      # similar to <tt>[:scheme, :proto]</tt>.  You can remove either or
      # both of the entries in array to ignore that respective header.
      attr_accessor :x_forwarded_proto_priority
    end

    @forwarded_priority = [:forwarded, :x_forwarded]
    @x_forwarded_proto_priority = [:proto, :scheme]

    valid_ipv4_octet = /\.(25[0-5]|2[0-4][0-9]|[01]?[0-9]?[0-9])/

    trusted_proxies = Regexp.union(
      /\A127#{valid_ipv4_octet}{3}\z/,                          # localhost IPv4 range 127.x.x.x, per RFC-3330
      /\A::1\z/,                                                # localhost IPv6 ::1
      /\Af[cd][0-9a-f]{2}(?::[0-9a-f]{0,4}){0,7}\z/i,           # private IPv6 range fc00 .. fdff
      /\A10#{valid_ipv4_octet}{3}\z/,                           # private IPv4 range 10.x.x.x
      /\A172\.(1[6-9]|2[0-9]|3[01])#{valid_ipv4_octet}{2}\z/,   # private IPv4 range 172.16.0.0 .. 172.31.255.255
      /\A192\.168#{valid_ipv4_octet}{2}\z/,                     # private IPv4 range 192.168.x.x
      /\Alocalhost\z|\Aunix(\z|:)/i,                            # localhost hostname, and unix domain sockets
    )

    self.ip_filter = lambda { |ip| trusted_proxies.match?(ip) }

    ALLOWED_SCHEMES = %w(https http wss ws).freeze

    def initialize(env)
      @env = env
      @params = nil
    end

    def params
      @params ||= super
    end

    def update_param(k, v)
      super
      @params = nil
    end

    def delete_param(k)
      v = super
      @params = nil
      v
    end

    module Env
      # The environment of the request.
      attr_reader :env

      def initialize(env)
        @env = env
        # This module is included at least in `ActionDispatch::Request`
        # The call to `super()` allows additional mixed-in initializers are called
        super()
      end

      # Predicate method to test to see if `name` has been set as request
      # specific data
      def has_header?(name)
        @env.key? name
      end

      # Get a request specific value for `name`.
      def get_header(name)
        @env[name]
      end

      # If a block is given, it yields to the block if the value hasn't been set
      # on the request.
      def fetch_header(name, &block)
        @env.fetch(name, &block)
      end

      # Loops through each key / value pair in the request specific data.
      def each_header(&block)
        @env.each(&block)
      end

      # Set a request specific value for `name` to `v`
      def set_header(name, v)
        @env[name] = v
      end

      # Add a header that may have multiple values.
      #
      # Example:
      #   request.add_header 'Accept', 'image/png'
      #   request.add_header 'Accept', '*/*'
      #
      #   assert_equal 'image/png,*/*', request.get_header('Accept')
      #
      # http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2
      def add_header(key, v)
        if v.nil?
          get_header key
        elsif has_header? key
          set_header key, "#{get_header key},#{v}"
        else
          set_header key, v
        end
      end

      # Delete a request specific value for `name`.
      def delete_header(name)
        @env.delete name
      end

      def initialize_copy(other)
        @env = other.env.dup
      end
    end

    module Helpers
      # The set of form-data media-types. Requests that do not indicate
      # one of the media types present in this list will not be eligible
      # for form-data / param parsing.
      FORM_DATA_MEDIA_TYPES = [
        'application/x-www-form-urlencoded',
        'multipart/form-data'
      ]

      # The set of media-types. Requests that do not indicate
      # one of the media types present in this list will not be eligible
      # for param parsing like soap attachments or generic multiparts
      PARSEABLE_DATA_MEDIA_TYPES = [
        'multipart/related',
        'multipart/mixed'
      ]

      # Default ports depending on scheme. Used to decide whether or not
      # to include the port in a generated URI.
      DEFAULT_PORTS = { 'http' => 80, 'https' => 443, 'coffee' => 80 }

      # The address of the client which connected to the proxy.
      HTTP_X_FORWARDED_FOR = 'HTTP_X_FORWARDED_FOR'

      # The contents of the host/:authority header sent to the proxy.
      HTTP_X_FORWARDED_HOST = 'HTTP_X_FORWARDED_HOST'

      HTTP_FORWARDED          = 'HTTP_FORWARDED'

      # The value of the scheme sent to the proxy.
      HTTP_X_FORWARDED_SCHEME = 'HTTP_X_FORWARDED_SCHEME'

      # The protocol used to connect to the proxy.
      HTTP_X_FORWARDED_PROTO = 'HTTP_X_FORWARDED_PROTO'

      # The port used to connect to the proxy.
      HTTP_X_FORWARDED_PORT = 'HTTP_X_FORWARDED_PORT'

      # Another way for specifying https scheme was used.
      HTTP_X_FORWARDED_SSL = 'HTTP_X_FORWARDED_SSL'

      def body;            get_header(RACK_INPUT)                         end
      def script_name;     get_header(SCRIPT_NAME).to_s                   end
      def script_name=(s); set_header(SCRIPT_NAME, s.to_s)                end

      def path_info;       get_header(PATH_INFO).to_s                     end
      def path_info=(s);   set_header(PATH_INFO, s.to_s)                  end

      def request_method;  get_header(REQUEST_METHOD)                     end
      def query_string;    get_header(QUERY_STRING).to_s                  end
      def content_length;  get_header('CONTENT_LENGTH')                   end
      def logger;          get_header(RACK_LOGGER)                        end
      def user_agent;      get_header('HTTP_USER_AGENT')                  end

      # the referer of the client
      def referer;         get_header('HTTP_REFERER')                     end
      alias referrer referer

      def session
        fetch_header(RACK_SESSION) do |k|
          set_header RACK_SESSION, default_session
        end
      end

      def session_options
        fetch_header(RACK_SESSION_OPTIONS) do |k|
          set_header RACK_SESSION_OPTIONS, {}
        end
      end

      # Checks the HTTP request method (or verb) to see if it was of type DELETE
      def delete?;  request_method == DELETE  end

      # Checks the HTTP request method (or verb) to see if it was of type GET
      def get?;     request_method == GET     end

      # Checks the HTTP request method (or verb) to see if it was of type HEAD
      def head?;    request_method == HEAD    end

      # Checks the HTTP request method (or verb) to see if it was of type OPTIONS
      def options?; request_method == OPTIONS end

      # Checks the HTTP request method (or verb) to see if it was of type LINK
      def link?;    request_method == LINK    end

      # Checks the HTTP request method (or verb) to see if it was of type PATCH
      def patch?;   request_method == PATCH   end

      # Checks the HTTP request method (or verb) to see if it was of type POST
      def post?;    request_method == POST    end

      # Checks the HTTP request method (or verb) to see if it was of type PUT
      def put?;     request_method == PUT     end

      # Checks the HTTP request method (or verb) to see if it was of type TRACE
      def trace?;   request_method == TRACE   end

      # Checks the HTTP request method (or verb) to see if it was of type UNLINK
      def unlink?;  request_method == UNLINK  end

      def scheme
        if get_header(HTTPS) == 'on'
          'https'
        elsif get_header(HTTP_X_FORWARDED_SSL) == 'on'
          'https'
        elsif forwarded_scheme
          forwarded_scheme
        else
          get_header(RACK_URL_SCHEME)
        end
      end

      # The authority of the incoming request as defined by RFC3976.
      # https://tools.ietf.org/html/rfc3986#section-3.2
      #
      # In HTTP/1, this is the `host` header.
      # In HTTP/2, this is the `:authority` pseudo-header.
      def authority
        forwarded_authority || host_authority || server_authority
      end

      # The authority as defined by the `SERVER_NAME` and `SERVER_PORT`
      # variables.
      def server_authority
        host = self.server_name
        port = self.server_port

        if host
          if port
            "#{host}:#{port}"
          else
            host
          end
        end
      end

      def server_name
        get_header(SERVER_NAME)
      end

      def server_port
        get_header(SERVER_PORT)
      end

      def cookies
        hash = fetch_header(RACK_REQUEST_COOKIE_HASH) do |key|
          set_header(key, {})
        end

        string = get_header(HTTP_COOKIE)

        unless string == get_header(RACK_REQUEST_COOKIE_STRING)
          hash.replace Utils.parse_cookies_header(string)
          set_header(RACK_REQUEST_COOKIE_STRING, string)
        end

        hash
      end

      def content_type
        content_type = get_header('CONTENT_TYPE')
        content_type.nil? || content_type.empty? ? nil : content_type
      end

      def xhr?
        get_header("HTTP_X_REQUESTED_WITH") == "XMLHttpRequest"
      end

      # The `HTTP_HOST` header.
      def host_authority
        get_header(HTTP_HOST)
      end

      def host_with_port(authority = self.authority)
        host, _, port = split_authority(authority)

        if port == DEFAULT_PORTS[self.scheme]
          host
        else
          authority
        end
      end

      # Returns a formatted host, suitable for being used in a URI.
      def host
        split_authority(self.authority)[0]
      end

      # Returns an address suitable for being to resolve to an address.
      # In the case of a domain name or IPv4 address, the result is the same
      # as +host+. In the case of IPv6 or future address formats, the square
      # brackets are removed.
      def hostname
        split_authority(self.authority)[1]
      end

      def port
        if authority = self.authority
          _, _, port = split_authority(authority)
        end

        port || forwarded_port&.last || DEFAULT_PORTS[scheme] || server_port
      end

      def forwarded_for
        forwarded_priority.each do |type|
          case type
          when :forwarded
            if forwarded_for = get_http_forwarded(:for)
              return(forwarded_for.map! do |authority|
                split_authority(authority)[1]
              end)
            end
          when :x_forwarded
            if value = get_header(HTTP_X_FORWARDED_FOR)
              return(split_header(value).map do |authority|
                split_authority(wrap_ipv6(authority))[1]
              end)
            end
          end
        end

        nil
      end

      def forwarded_port
        forwarded_priority.each do |type|
          case type
          when :forwarded
            if forwarded = get_http_forwarded(:for)
              return(forwarded.map do |authority|
                split_authority(authority)[2]
              end.compact)
            end
          when :x_forwarded
            if value = get_header(HTTP_X_FORWARDED_PORT)
              return split_header(value).map(&:to_i)
            end
          end
        end

        nil
      end

      def forwarded_authority
        forwarded_priority.each do |type|
          case type
          when :forwarded
            if forwarded = get_http_forwarded(:host)
              return forwarded.last
            end
          when :x_forwarded
            if value = get_header(HTTP_X_FORWARDED_HOST)
              return wrap_ipv6(split_header(value).last)
            end
          end
        end

        nil
      end

      def ssl?
        scheme == 'https' || scheme == 'wss'
      end

      def ip
        remote_addresses = split_header(get_header('REMOTE_ADDR'))
        external_addresses = reject_trusted_ip_addresses(remote_addresses)

        unless external_addresses.empty?
          return external_addresses.last
        end

        if (forwarded_for = self.forwarded_for) && !forwarded_for.empty?
          # The forwarded for addresses are ordered: client, proxy1, proxy2.
          # So we reject all the trusted addresses (proxy*) and return the
          # last client. Or if we trust everyone, we just return the first
          # address.
          return reject_trusted_ip_addresses(forwarded_for).last || forwarded_for.first
        end

        # If all the addresses are trusted, and we aren't forwarded, just return
        # the first remote address, which represents the source of the request.
        remote_addresses.first
      end

      # The media type (type/subtype) portion of the CONTENT_TYPE header
      # without any media type parameters. e.g., when CONTENT_TYPE is
      # "text/plain;charset=utf-8", the media-type is "text/plain".
      #
      # For more information on the use of media types in HTTP, see:
      # http://www.w3.org/Protocols/rfc2616/rfc2616-sec3.html#sec3.7
      def media_type
        MediaType.type(content_type)
      end

      # The media type parameters provided in CONTENT_TYPE as a Hash, or
      # an empty Hash if no CONTENT_TYPE or media-type parameters were
      # provided.  e.g., when the CONTENT_TYPE is "text/plain;charset=utf-8",
      # this method responds with the following Hash:
      #   { 'charset' => 'utf-8' }
      def media_type_params
        MediaType.params(content_type)
      end

      # The character set of the request body if a "charset" media type
      # parameter was given, or nil if no "charset" was specified. Note
      # that, per RFC2616, text/* media types that specify no explicit
      # charset are to be considered ISO-8859-1.
      def content_charset
        media_type_params['charset']
      end

      # Determine whether the request body contains form-data by checking
      # the request content-type for one of the media-types:
      # "application/x-www-form-urlencoded" or "multipart/form-data". The
      # list of form-data media types can be modified through the
      # +FORM_DATA_MEDIA_TYPES+ array.
      #
      # A request body is also assumed to contain form-data when no
      # content-type header is provided and the request_method is POST.
      def form_data?
        type = media_type
        meth = get_header(RACK_METHODOVERRIDE_ORIGINAL_METHOD) || get_header(REQUEST_METHOD)

        (meth == POST && type.nil?) || FORM_DATA_MEDIA_TYPES.include?(type)
      end

      # Determine whether the request body contains data by checking
      # the request media_type against registered parse-data media-types
      def parseable_data?
        PARSEABLE_DATA_MEDIA_TYPES.include?(media_type)
      end

      # Returns the data received in the query string.
      def GET
        rr_query_string = get_header(RACK_REQUEST_QUERY_STRING)
        query_string = self.query_string
        if rr_query_string == query_string
          get_header(RACK_REQUEST_QUERY_HASH)
        else
          if rr_query_string
            warn "query string used for GET parsing different from current query string. Starting in Rack 3.2, Rack will used the cached GET value instead of parsing the current query string.", uplevel: 1
          end
          query_hash = parse_query(query_string, '&')
          set_header(RACK_REQUEST_QUERY_STRING, query_string)
          set_header(RACK_REQUEST_QUERY_HASH, query_hash)
        end
      end

      # Returns the data received in the request body.
      #
      # This method support both application/x-www-form-urlencoded and
      # multipart/form-data.
      def POST
        if error = get_header(RACK_REQUEST_FORM_ERROR)
          raise error.class, error.message, cause: error.cause
        end

        begin
          rack_input = get_header(RACK_INPUT)

          # If the form hash was already memoized:
          if form_hash = get_header(RACK_REQUEST_FORM_HASH)
            form_input = get_header(RACK_REQUEST_FORM_INPUT)
            # And it was memoized from the same input:
            if form_input.equal?(rack_input)
              return form_hash
            elsif form_input
              warn "input stream used for POST parsing different from current input stream. Starting in Rack 3.2, Rack will used the cached POST value instead of parsing the current input stream.", uplevel: 1
            end
          end

          # Otherwise, figure out how to parse the input:
          if rack_input.nil?
            set_header RACK_REQUEST_FORM_INPUT, nil
            set_header(RACK_REQUEST_FORM_HASH, {})
          elsif form_data? || parseable_data?
            if pairs = Rack::Multipart.parse_multipart(env, Rack::Multipart::ParamList)
              set_header RACK_REQUEST_FORM_PAIRS, pairs
              set_header RACK_REQUEST_FORM_HASH, expand_param_pairs(pairs)
            else
              form_vars = get_header(RACK_INPUT).read

              # Fix for Safari Ajax postings that always append \0
              # form_vars.sub!(/\0\z/, '') # performance replacement:
              form_vars.slice!(-1) if form_vars.end_with?("\0")

              set_header RACK_REQUEST_FORM_VARS, form_vars
              set_header RACK_REQUEST_FORM_HASH, parse_query(form_vars, '&')
            end

            set_header RACK_REQUEST_FORM_INPUT, get_header(RACK_INPUT)
            get_header RACK_REQUEST_FORM_HASH
          else
            set_header RACK_REQUEST_FORM_INPUT, get_header(RACK_INPUT)
            set_header(RACK_REQUEST_FORM_HASH, {})
          end
        rescue => error
          set_header(RACK_REQUEST_FORM_ERROR, error)
          raise
        end
      end

      # The union of GET and POST data.
      #
      # Note that modifications will not be persisted in the env. Use update_param or delete_param if you want to destructively modify params.
      def params
        self.GET.merge(self.POST)
      end

      # Destructively update a parameter, whether it's in GET and/or POST. Returns nil.
      #
      # The parameter is updated wherever it was previous defined, so GET, POST, or both. If it wasn't previously defined, it's inserted into GET.
      #
      # <tt>env['rack.input']</tt> is not touched.
      def update_param(k, v)
        found = false
        if self.GET.has_key?(k)
          found = true
          self.GET[k] = v
        end
        if self.POST.has_key?(k)
          found = true
          self.POST[k] = v
        end
        unless found
          self.GET[k] = v
        end
      end

      # Destructively delete a parameter, whether it's in GET or POST. Returns the value of the deleted parameter.
      #
      # If the parameter is in both GET and POST, the POST value takes precedence since that's how #params works.
      #
      # <tt>env['rack.input']</tt> is not touched.
      def delete_param(k)
        post_value, get_value = self.POST.delete(k), self.GET.delete(k)
        post_value || get_value
      end

      def base_url
        "#{scheme}://#{host_with_port}"
      end

      # Tries to return a remake of the original request URL as a string.
      def url
        base_url + fullpath
      end

      def path
        script_name + path_info
      end

      def fullpath
        query_string.empty? ? path : "#{path}?#{query_string}"
      end

      def accept_encoding
        parse_http_accept_header(get_header("HTTP_ACCEPT_ENCODING"))
      end

      def accept_language
        parse_http_accept_header(get_header("HTTP_ACCEPT_LANGUAGE"))
      end

      def trusted_proxy?(ip)
        Rack::Request.ip_filter.call(ip)
      end

      # like Hash#values_at
      def values_at(*keys)
        warn("Request#values_at is deprecated and will be removed in a future version of Rack. Please use request.params.values_at instead", uplevel: 1)
        
        keys.map { |key| params[key] }
      end

      private

      def default_session; {}; end

      # Assist with compatibility when processing `X-Forwarded-For`.
      def wrap_ipv6(host)
        # Even thought IPv6 addresses should be wrapped in square brackets,
        # sometimes this is not done in various legacy/underspecified headers.
        # So we try to fix this situation for compatibility reasons.

        # Try to detect IPv6 addresses which aren't escaped yet:
        if !host.start_with?('[') && host.count(':') > 1
          "[#{host}]"
        else
          host
        end
      end

      def parse_http_accept_header(header)
        # It would be nice to use filter_map here, but it's Ruby 2.7+
        parts = header.to_s.split(',')

        parts.map! do |part|
          part.strip!
          next if part.empty?

          attribute, parameters = part.split(';', 2)
          attribute.strip!
          parameters&.strip!
          quality = 1.0
          if parameters and /\Aq=([\d.]+)/ =~ parameters
            quality = $1.to_f
          end
          [attribute, quality]
        end

        parts.compact!

        parts
      end

      # Get an array of values set in the RFC 7239 `Forwarded` request header.
      def get_http_forwarded(token)
        Utils.forwarded_values(get_header(HTTP_FORWARDED))&.[](token)
      end

      def query_parser
        Utils.default_query_parser
      end

      def parse_query(qs, d = '&')
        query_parser.parse_nested_query(qs, d)
      end

      def parse_multipart
        Rack::Multipart.extract_multipart(self, query_parser)
      end

      def expand_param_pairs(pairs, query_parser = query_parser())
        params = query_parser.make_params

        pairs.each do |k, v|
          query_parser.normalize_params(params, k, v)
        end

        params.to_params_hash
      end

      def split_header(value)
        value ? value.strip.split(/[,\s]+/) : []
      end

      # ipv6 extracted from resolv stdlib, simplified
      # to remove numbered match group creation.
      ipv6 = Regexp.union(
        /(?:[0-9A-Fa-f]{1,4}:){7}
         [0-9A-Fa-f]{1,4}/x,
        /(?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)? ::
         (?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?/x,
        /(?:[0-9A-Fa-f]{1,4}:){6,6}
         \d+\.\d+\.\d+\.\d+/x,
        /(?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)? ::
         (?:[0-9A-Fa-f]{1,4}:)*
         \d+\.\d+\.\d+\.\d+/x,
        /[Ff][Ee]80
         (?::[0-9A-Fa-f]{1,4}){7}
         %[-0-9A-Za-z._~]+/x,
        /[Ff][Ee]80:
         (?:
           (?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)? ::
           (?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?
           |
           :(?:[0-9A-Fa-f]{1,4}(?::[0-9A-Fa-f]{1,4})*)?
         )?
         :[0-9A-Fa-f]{1,4}%[-0-9A-Za-z._~]+/x)

      AUTHORITY = /
        \A
        (?<host>
          # Match IPv6 as a string of hex digits and colons in square brackets
          \[(?<address>#{ipv6})\]
          |
          # Match any other printable string (except square brackets) as a hostname
          (?<address>[[[:graph:]&&[^\[\]]]]*?)
        )
        (:(?<port>\d+))?
        \z
      /x

      private_constant :AUTHORITY

      def split_authority(authority)
        return [] if authority.nil?
        return [] unless match = AUTHORITY.match(authority)
        return match[:host], match[:address], match[:port]&.to_i
      end

      def reject_trusted_ip_addresses(ip_addresses)
        ip_addresses.reject { |ip| trusted_proxy?(ip) }
      end

      FORWARDED_SCHEME_HEADERS = {
        proto: HTTP_X_FORWARDED_PROTO,
        scheme: HTTP_X_FORWARDED_SCHEME
      }.freeze
      private_constant :FORWARDED_SCHEME_HEADERS
      def forwarded_scheme
        forwarded_priority.each do |type|
          case type
          when :forwarded
            if (forwarded_proto = get_http_forwarded(:proto)) &&
               (scheme = allowed_scheme(forwarded_proto.last))
              return scheme
            end
          when :x_forwarded
            x_forwarded_proto_priority.each do |x_type|
              if header = FORWARDED_SCHEME_HEADERS[x_type]
                split_header(get_header(header)).reverse_each do |scheme|
                  if allowed_scheme(scheme)
                    return scheme
                  end
                end
              end
            end
          end
        end

        nil
      end

      def allowed_scheme(header)
        header if ALLOWED_SCHEMES.include?(header)
      end

      def forwarded_priority
        Request.forwarded_priority
      end

      def x_forwarded_proto_priority
        Request.x_forwarded_proto_priority
      end
    end

    include Env
    include Helpers
  end
end

# :nocov:
require_relative 'multipart' unless defined?(Rack::Multipart)
# :nocov:
