#
# Author:: Adam Jacob (<adam@chef.io>)
# Copyright:: Copyright 2010-2019, Chef Software Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#

require "chef/knife"
require "chef/knife/data_bag_secret_options"
require "chef/dist"

class Chef
  class Knife
    class Bootstrap < Knife
      include DataBagSecretOptions

      SUPPORTED_CONNECTION_PROTOCOLS = %w{ssh winrm}.freeze
      WINRM_AUTH_PROTOCOL_LIST = %w{plaintext kerberos ssl negotiate}.freeze

      # Common connectivity options
      option :connection_user,
        short: "-U USERNAME",
        long: "--connection-user USERNAME",
        description: "Authenticate to the target host with this user account"

      option :connection_password,
        short: "-P PASSWORD",
        long: "--connection-password PASSWORD",
        description: "Authenticate to the target host with this password"

      option :connection_port,
        short: "-p PORT",
        long: "--connection-port PORT",
        description: "The port on the target node to connect to."

      option :connection_protocol,
        short: "-o PROTOCOL",
        long: "--connection-protocol PROTOCOL",
        description: "The protocol to use to connect to the target node.  Supports: #{SUPPORTED_CONNECTION_PROTOCOLS.join(" ")}"

      option :max_wait,
        short: "-W SECONDS",
        long: "--max-wait SECONDS",
        description: "The maximum time to wait for the initial connection to be established."

      # WinRM Authentication
      option :winrm_ssl_peer_fingerprint,
        long: "--winrm-ssl-peer-fingerprint FINGERPRINT",
        description: "SSL certificate fingerprint expected from the target."

      option :ca_trust_file,
        short: "-f CA_TRUST_PATH",
        long: "--ca-trust-file CA_TRUST_PATH",
        description: "The Certificate Authority (CA) trust file used for SSL transport"

      option :winrm_no_verify_cert,
        long: "--winrm-no-verify-cert",
        description: "Do not verify the SSL certificate of the target node for WinRM.",
        boolean: true

      option :winrm_ssl,
        long: "--winrm-ssl",
        description: "Connect to WinRM using SSL"

      option :winrm_auth_method,
        short: "-w AUTH-METHOD",
        long: "--winrm-auth-method AUTH-METHOD",
        description: "The WinRM authentication method to use. Valid choices are #{WINRM_AUTH_PROTOCOL_LIST}",
        proc: Proc.new { |protocol| Chef::Config[:knife][:winrm_auth_method] = protocol }

      option :winrm_basic_auth_only,
        long: "--winrm-basic-auth-only",
        description: "For WinRM basic authentication when using the 'ssl' auth method",
        boolean: true

        # This option was provided in knife bootstrap windows winrm,
        # but it is ignored  in knife-windows/WinrmSession, and so remains unimplemeneted here.
        # option :kerberos_keytab_file,
        #   :short => "-T KEYTAB_FILE",
        #   :long => "--keytab-file KEYTAB_FILE",
        #   :description => "The Kerberos keytab file used for authentication",
        #   :proc => Proc.new { |keytab| Chef::Config[:knife][:kerberos_keytab_file] = keytab }

      option :kerberos_realm,
        short: "-R KERBEROS_REALM",
        long: "--kerberos-realm KERBEROS_REALM",
        description: "The Kerberos realm used for authentication",
        proc: Proc.new { |protocol| Chef::Config[:knife][:kerberos_realm] = protocol }

      option :kerberos_service,
        short: "-S KERBEROS_SERVICE",
        long: "--kerberos-service KERBEROS_SERVICE",
        description: "The Kerberos service used for authentication",
        proc: Proc.new { |protocol| Chef::Config[:knife][:kerberos_service] = protocol }

      option :winrm_session_timeout,
        long: "--winrm-session-timeout SECONDS",
        description: "The number of seconds to wait for each WinRM operation to be acknowledged while running bootstrap",
        proc: Proc.new { |protocol| Chef::Config[:knife][:winrm_session_timeout] = protocol }

      ## SSH Authentication
      option :ssh_gateway,
        short: "-G GATEWAY",
        long: "--ssh-gateway GATEWAY",
        description: "The ssh gateway",
        proc: Proc.new { |key| Chef::Config[:knife][:ssh_gateway] = key }

      option :ssh_gateway_identity,
        long: "--ssh-gateway-identity SSH_GATEWAY_IDENTITY",
        description: "The SSH identity file used for gateway authentication",
        proc: Proc.new { |key| Chef::Config[:knife][:ssh_gateway_identity] = key }

      option :ssh_forward_agent,
        short: "-A",
        long: "--ssh-forward-agent",
        description: "Enable SSH agent forwarding",
        boolean: true

      option :ssh_identity_file,
        short: "-i IDENTITY_FILE",
        long: "--ssh-identity-file IDENTITY_FILE",
        description: "The SSH identity file used for authentication"

      option :ssh_verify_host_key,
        long: "--[no-]ssh-verify-host-key",
        description: "Verify host key, enabled by default.",
        boolean: true

      #
      # bootstrap options
      #

      # client.rb content via chef-full/bootstrap_context
      option :bootstrap_version,
        long: "--bootstrap-version VERSION",
        description: "The version of Chef to install",
        proc: lambda { |v| Chef::Config[:knife][:bootstrap_version] = v }

      # client.rb content via chef-full/bootstrap_context
      option :bootstrap_proxy,
        long: "--bootstrap-proxy PROXY_URL",
        description: "The proxy server for the node being bootstrapped",
        proc: Proc.new { |p| Chef::Config[:knife][:bootstrap_proxy] = p }

      # client.rb content via bootstrap_context
      option :bootstrap_proxy_user,
        long: "--bootstrap-proxy-user PROXY_USER",
        description: "The proxy authentication username for the node being bootstrapped"

      # client.rb content via bootstrap_context
      option :bootstrap_proxy_pass,
        long: "--bootstrap-proxy-pass PROXY_PASS",
        description: "The proxy authentication password for the node being bootstrapped"

      # client.rb content via bootstrap_context
      option :bootstrap_no_proxy,
        long: "--bootstrap-no-proxy [NO_PROXY_URL|NO_PROXY_IP]",
        description: "Do not proxy locations for the node being bootstrapped; this option is used internally by Chef",
        proc: Proc.new { |np| Chef::Config[:knife][:bootstrap_no_proxy] = np }

      # client.rb content via bootstrap_context
      option :bootstrap_template,
        short: "-t TEMPLATE",
        long: "--bootstrap-template TEMPLATE",
        description: "Bootstrap Chef using a built-in or custom template. Set to the full path of an erb template or use one of the built-in templates."

      # client.rb content via bootstrap_context
      option :node_ssl_verify_mode,
        long: "--node-ssl-verify-mode [peer|none]",
        description: "Whether or not to verify the SSL cert for all HTTPS requests.",
        proc: Proc.new { |v|
          valid_values = %w{none peer}
          unless valid_values.include?(v)
            raise "Invalid value '#{v}' for --node-ssl-verify-mode. Valid values are: #{valid_values.join(", ")}"
          end
          v
        }

      # bootstrap_context - client.rb
      option :node_verify_api_cert,
        long: "--[no-]node-verify-api-cert",
        description: "Verify the SSL cert for HTTPS requests to the Chef server API.",
        boolean: true

      # runtime - sudo settings (train handles sudo)
      option :use_sudo,
        long: "--sudo",
        description: "Execute the bootstrap via sudo",
        boolean: true

      # runtime - sudo settings (train handles sudo)
      option :preserve_home,
        long: "--sudo-preserve-home",
        description: "Preserve non-root user HOME environment variable with sudo",
        boolean: true

      # runtime - sudo settings (train handles sudo)
      option :use_sudo_password,
        long: "--use-sudo-password",
        description: "Execute the bootstrap via sudo with password",
        boolean: false

      # runtime - client_builder
      option :chef_node_name,
        short: "-N NAME",
        long: "--node-name NAME",
        description: "The Chef node name for your new node"

      # runtime - client_builder - set runlist when creating node
      option :run_list,
        short: "-r RUN_LIST",
        long: "--run-list RUN_LIST",
        description: "Comma separated list of roles/recipes to apply",
        proc: lambda { |o| o.split(/[\s,]+/) },
        default: []

      # runtime - client_builder - set policy name when creating node
      option :policy_name,
        long: "--policy-name POLICY_NAME",
        description: "Policyfile name to use (--policy-group must also be given)",
        default: nil

      # runtime - client_builder - set policy group when creating node
      option :policy_group,
        long: "--policy-group POLICY_GROUP",
        description: "Policy group name to use (--policy-name must also be given)",
        default: nil

      # runtime - client_builder -  node tags
      option :tags,
        long: "--tags TAGS",
        description: "Comma separated list of tags to apply to the node",
        proc: lambda { |o| o.split(/[\s,]+/) },
        default: []

      # bootstrap template
      option :first_boot_attributes,
        short: "-j JSON_ATTRIBS",
        long: "--json-attributes",
        description: "A JSON string to be added to the first run of #{Chef::Dist::CLIENT}",
        proc: lambda { |o| Chef::JSONCompat.parse(o) },
        default: nil

      # bootstrap template
      option :first_boot_attributes_from_file,
        long: "--json-attribute-file FILE",
        description: "A JSON file to be used to the first run of #{Chef::Dist::CLIENT}",
        proc: lambda { |o| Chef::JSONCompat.parse(File.read(o)) },
        default: nil

      # Note that several of the below options are used by bootstrap template,
      # but only from the passed-in knife config; it does not use the
      # config from the CLI for those values.  We cannot always used the merged
      # config, because in some cases the knife keys thIn those cases, the option
      # will have a proc that assigns the value into Chef::Config[:knife]

      # bootstrap template
      # Create ohai hints in /etc/chef/ohai/hints, fname=hintname, content=value
      option :hint,
        long: "--hint HINT_NAME[=HINT_FILE]",
        description: "Specify Ohai Hint to be set on the bootstrap target. Use multiple --hint options to specify multiple hints.",
        proc: Proc.new { |h|
          Chef::Config[:knife][:hints] ||= Hash.new
          name, path = h.split("=")
          Chef::Config[:knife][:hints][name] = path ? Chef::JSONCompat.parse(::File.read(path)) : Hash.new
        }

      # bootstrap override: url of a an installer shell script touse in place of omnitruck
      # Note that the bootstrap template _only_ references this out of Chef::Config, and not from
      # the provided options to knife bootstrap, so we set the Chef::Config option here.
      option :bootstrap_url,
        long: "--bootstrap-url URL",
        description: "URL to a custom installation script",
        proc: Proc.new { |u| Chef::Config[:knife][:bootstrap_url] = u }

      option :msi_url, # Windows target only
        short: "-m URL",
        long: "--msi-url URL",
        description: "Location of the #{Chef::Dist::PRODUCT} MSI. The default templates will prefer to download from this location. The MSI will be downloaded from chef.io if not provided (windows).",
        default: ""

      # bootstrap override: Do this instead of our own setup.sh from omnitruck. Causes bootstrap_url to be ignored.
      option :bootstrap_install_command,
        long: "--bootstrap-install-command COMMANDS",
        description: "Custom command to install #{Chef::Dist::CLIENT}",
        proc: Proc.new { |ic| Chef::Config[:knife][:bootstrap_install_command] = ic }

      # bootstrap template: Run this command first in the bootstrap script
      option :bootstrap_preinstall_command,
        long: "--bootstrap-preinstall-command COMMANDS",
        description: "Custom commands to run before installing #{Chef::Dist::CLIENT}",
        proc: Proc.new { |preic| Chef::Config[:knife][:bootstrap_preinstall_command] = preic }

      # bootstrap template
      option :bootstrap_wget_options,
        long: "--bootstrap-wget-options OPTIONS",
        description: "Add options to wget when installing #{Chef::Dist::CLIENT}",
        proc: Proc.new { |wo| Chef::Config[:knife][:bootstrap_wget_options] = wo }

      # bootstrap template
      option :bootstrap_curl_options,
        long: "--bootstrap-curl-options OPTIONS",
        description: "Add options to curl when install #{Chef::Dist::CLIENT}",
        proc: Proc.new { |co| Chef::Config[:knife][:bootstrap_curl_options] = co }

      # chef_vault_handler
      option :bootstrap_vault_file,
        long: "--bootstrap-vault-file VAULT_FILE",
        description: "A JSON file with a list of vault(s) and item(s) to be updated"

      # chef_vault_handler
      option :bootstrap_vault_json,
        long: "--bootstrap-vault-json VAULT_JSON",
        description: "A JSON string with the vault(s) and item(s) to be updated"

      # chef_vault_handler
      option :bootstrap_vault_item,
        long: "--bootstrap-vault-item VAULT_ITEM",
        description: 'A single vault and item to update as "vault:item"',
        proc: Proc.new { |i|
          (vault, item) = i.split(/:/)
          Chef::Config[:knife][:bootstrap_vault_item] ||= {}
          Chef::Config[:knife][:bootstrap_vault_item][vault] ||= []
          Chef::Config[:knife][:bootstrap_vault_item][vault].push(item)
          Chef::Config[:knife][:bootstrap_vault_item]
        }

      DEPRECATED_FLAGS = {
        # deprecated_key: [new_key, deprecated_long]
        auth_timeout: [:max_wait, "--max-wait SECONDS"],
        host_key_verify: [:ssh_verify_host_key,
                          "--[no-]host-key-verify",
                          ],
        ssh_user: [:connection_user,
                   "--ssh-user USER",
                   ],
        ssh_password: [:connection_password,
                       "--ssh-password PASSWORD",
                       ],
        ssh_port: [:connection_port,
                   "-ssh-port",
                   ],
        ssl_peer_fingerprint: [:winrm_ssl_peer_fingerprint,
                               "--ssl-peer-fingerprint FINGERPRINT",
                               ],
        winrm_user: [:connection_user,
                     "--winrm-user USER",
                     ],
        winrm_password: [:connection_password,
                         "--winrm-password",
                         ],
        winrm_port: [:connection_port,
                     "--winrm-port",
                     ],
        winrm_authentication_protocol: [:winrm_auth_method,
                                        "--winrm-authentication-protocol PROTOCOL",
                                        ],
      }.freeze

      DEPRECATED_FLAGS.each do |deprecated_key, deprecation_entry|
        new_key, deprecated_long = deprecation_entry
        new_long = options[new_key][:long]
        option(deprecated_key, long: deprecated_long,
                               description: "#{deprecated_long} is deprecated. Use #{new_long} instead.",
                               boolean: options[new_key][:boolean])
      end

      attr_accessor :client_builder
      attr_accessor :chef_vault_handler
      attr_reader   :connection

      deps do
        require "erubis"

        require "chef/json_compat"
        require "chef/util/path_helper"
        require "chef/knife/bootstrap/chef_vault_handler"
        require "chef/knife/bootstrap/client_builder"
        require "chef/knife/bootstrap/train_connector"
      end

      banner "knife bootstrap [PROTOCOL://][USER@]FQDN (options)"

      def initialize(argv = [])
        super
        @client_builder = Chef::Knife::Bootstrap::ClientBuilder.new(
          chef_config: Chef::Config,
          knife_config: config,
          ui: ui
        )
        @chef_vault_handler = Chef::Knife::Bootstrap::ChefVaultHandler.new(
          knife_config: config,
          ui: ui
        )
      end

      # The default bootstrap template to use to bootstrap a server.
      # This is a public API hook which knife plugins use or inherit and override.
      #
      # @return [String] Default bootstrap template
      def default_bootstrap_template
        if connection.windows?
          "windows-#{Chef::Dist::CLIENT}-msi"
        else
          "chef-full"
        end
      end

      def host_descriptor
        Array(@name_args).first
      end

      # The server_name is the DNS or IP we are going to connect to, it is not necessarily
      # the node name, the fqdn, or the hostname of the server.  This is a public API hook
      # which knife plugins use or inherit and override.
      #
      # @return [String] The DNS or IP that bootstrap will connect to
      def server_name
        if host_descriptor
          @server_name ||= host_descriptor.split("@").reverse[0]
        end
      end

      # @return [String] The CLI specific bootstrap template or the default
      def bootstrap_template
        # Allow passing a bootstrap template or use the default
        config[:bootstrap_template] || default_bootstrap_template
      end

      def find_template
        template = bootstrap_template

        # Use the template directly if it's a path to an actual file
        if File.exists?(template)
          Chef::Log.trace("Using the specified bootstrap template: #{File.dirname(template)}")
          return template
        end

        # Otherwise search the template directories until we find the right one
        bootstrap_files = []
        bootstrap_files << File.join(File.dirname(__FILE__), "bootstrap/templates", "#{template}.erb")
        bootstrap_files << File.join(Knife.chef_config_dir, "bootstrap", "#{template}.erb") if Chef::Knife.chef_config_dir
        Chef::Util::PathHelper.home(".chef", "bootstrap", "#{template}.erb") { |p| bootstrap_files << p }
        bootstrap_files << Gem.find_files(File.join("chef", "knife", "bootstrap", "#{template}.erb"))
        bootstrap_files.flatten!

        template_file = Array(bootstrap_files).find do |bootstrap_template|
          Chef::Log.trace("Looking for bootstrap template in #{File.dirname(bootstrap_template)}")
          File.exists?(bootstrap_template)
        end

        unless template_file
          ui.info("Can not find bootstrap definition for #{template}")
          raise Errno::ENOENT
        end

        Chef::Log.trace("Found bootstrap template in #{File.dirname(template_file)}")

        template_file
      end

      def secret
        @secret ||= encryption_secret_provided_ignore_encrypt_flag? ? read_secret : nil
      end

      # Establish bootstrap context for template rendering.
      # Requires connection to be a live connection in order to determine
      # the correct platform.
      def bootstrap_context
        @bootstrap_context ||=
          if connection.windows?
            require "chef/knife/core/windows_bootstrap_context"
            Knife::Core::WindowsBootstrapContext.new(config, config[:run_list], Chef::Config, secret)
          else
            require "chef/knife/core/bootstrap_context"
            Knife::Core::BootstrapContext.new(config, config[:run_list], Chef::Config, secret)
          end
      end

      def first_boot_attributes
        @config[:first_boot_attributes] || @config[:first_boot_attributes_from_file] || {}
      end

      def render_template
        @config[:first_boot_attributes] = first_boot_attributes
        template_file = find_template
        template = IO.read(template_file).chomp
        Erubis::Eruby.new(template).evaluate(bootstrap_context)
      end

      def run
        verify_deprecated_flags!

        validate_name_args!
        validate_protocol!
        validate_first_boot_attributes!
        validate_winrm_transport_opts!
        validate_policy_options!

        winrm_warn_no_ssl_verification

        $stdout.sync = true
        register_client
        connect!
        unless client_builder.client_path.nil?
          bootstrap_context.client_pem = client_builder.client_path
        end
        content = render_template
        bootstrap_path = upload_bootstrap(content)
        perform_bootstrap(bootstrap_path)
      ensure
        connection.del_file!(bootstrap_path) if connection && bootstrap_path
      end

      def register_client
        # chef-vault integration must use the new client-side hawtness, otherwise to use the
        # new client-side hawtness, just delete your validation key.
        if chef_vault_handler.doing_chef_vault? ||
            (Chef::Config[:validation_key] &&
             !File.exist?(File.expand_path(Chef::Config[:validation_key])))

          unless config[:chef_node_name]
            ui.error("You must pass a node name with -N when bootstrapping with user credentials")
            exit 1
          end
          client_builder.run
          chef_vault_handler.run(client_builder.client)
        else
          ui.info <<~EOM
            Doing old-style registration with the validation key at #{Chef::Config[:validation_key]}..."
            Delete your validation key in order to use your user credentials instead
          EOM

        end
      end

      def perform_bootstrap(remote_bootstrap_script_path)
        ui.info("Bootstrapping #{ui.color(server_name, :bold)}")
        cmd = bootstrap_command(remote_bootstrap_script_path)
        r = connection.run_command(cmd) do |data|
          ui.msg("#{ui.color(" [#{connection.hostname}]", :cyan)} #{data}")
        end
        if r.exit_status != 0
          ui.error("The following error occurred on #{server_name}:")
          ui.error(r.stderr)
          exit 1
        end
      end

      def connect!
        ui.info("Connecting to #{ui.color(server_name, :bold)}")
        opts = connection_opts.dup
        do_connect(opts)
      rescue Train::Error => e
        require "net/ssh"
        if e.cause && e.cause.class == Net::SSH::AuthenticationFailed
          if connection.password_auth?
            raise
          else
            ui.warn("Failed to authenticate #{opts[:user]} to #{server_name} - trying password auth")
            password = ui.ask("Enter password for #{opts[:user]}@#{server_name}.") do |q|
              q.echo = false
            end
          end
          opts.merge! force_ssh_password_opts(password)
          do_connect(opts)
        else
          raise
        end
      end

      # url values override CLI flags, if you provide both
      # we'll use the one that you gave in the URL.
      def connection_protocol
        return @connection_protocol if @connection_protocol
        from_url = host_descriptor =~ /^(.*):\/\// ? $1 : nil
        from_cli = config[:connection_protocol]
        from_knife = Chef::Config[:knife][:connection_protocol]
        @connection_protocol = from_url || from_cli || from_knife || "ssh"
      end

      def do_connect(conn_options)
        @connection = TrainConnector.new(host_descriptor, connection_protocol, conn_options)
        connection.connect!
      end

      # Fail if both first_boot_attributes and first_boot_attributes_from_file
      # are set.
      def validate_first_boot_attributes!
        if @config[:first_boot_attributes] && @config[:first_boot_attributes_from_file]
          raise Chef::Exceptions::BootstrapCommandInputError
        end
        true
      end

      # Fail if using plaintext auth without ssl because
      # this can expose keys in plaintext on the wire.
      # TODO test for this method
      # TODO check that the protoocol is valid.
      def validate_winrm_transport_opts!
        return true unless winrm?

        if Chef::Config[:validation_key] && !File.exist?(File.expand_path(Chef::Config[:validation_key]))
          if config_value(:winrm_auth_method) == "plaintext" &&
              config_value(:winrm_ssl) != true
            ui.error <<~EOM
              Validatorless bootstrap over unsecure winrm channels could expose your
              key to network sniffing.
               Please use a 'winrm_auth_method' other than 'plaintext',
              or enable ssl on #{server_name} then use the --ssl flag
              to connect.
            EOM

            exit 1
          end
        end
        true
      end

      # If any deprecated flags are used, let the user know and
      # update config[new-key] to the value given to the deprecated flag.
      # If a deprecated flag and its corresponding replacement
      # are both used, raise an error.
      def verify_deprecated_flags!
        DEPRECATED_FLAGS.each do |deprecated_key, deprecation_entry|
          new_key, deprecated_long = deprecation_entry
          if config.key?(deprecated_key) && config_source(deprecated_key) == :cli
            if config.key?(new_key) && config_source(new_key) == :cli
              new_long = options[new_key][:long].split(" ").first
              deprecated_long = deprecated_long.split(" ").first
              ui.error <<~EOM
                You provided both #{new_long} and #{deprecated_long}.

                Please use one or the other, but note that
                #{deprecated_long} is deprecated.
              EOM
              exit 1
            else
              config[new_key] = config[deprecated_key]
              unless Chef::Config[:silence_deprecation_warnings] == true
                ui.warn options[deprecated_key][:description]
              end
            end
          end
        end
      end

      # fail if the server_name is nil
      def validate_name_args!
        if server_name.nil?
          ui.error("Must pass an FQDN or ip to bootstrap")
          exit 1
        end
      end

      # Ensure options are valid by checking policyfile values.
      #
      # The method call will cause the program to exit(1) if:
      #   * Only one of --policy-name and --policy-group is specified
      #   * Policyfile options are set and --run-list is set as well
      #
      # @return [TrueClass] If options are valid.
      def validate_policy_options!
        if incomplete_policyfile_options?
          ui.error("--policy-name and --policy-group must be specified together")
          exit 1
        elsif policyfile_and_run_list_given?
          ui.error("Policyfile options and --run-list are exclusive")
          exit 1
        end
      end

      # Ensure a valid protocol is provided for target host connection
      #
      # The method call will cause the program to exit(1) if:
      #   * Conflicting protocols are given via the target URI and the --protocol option
      #   * The protocol is not a supported protocol
      #
      # @return [TrueClass] If options are valid.
      def validate_protocol!
        from_cli = config[:connection_protocol]
        if from_cli && connection_protocol != from_cli
          # Hanging indent to align with the ERROR: prefix
          ui.error <<~EOM
            The URL '#{host_descriptor}' indicates protocol is '#{connection_protocol}'
            while the --protocol flag specifies '#{from_cli}'.  Please include
            only one or the other.
          EOM
          exit 1
        end

        unless SUPPORTED_CONNECTION_PROTOCOLS.include?(connection_protocol)
          ui.error <<~EOM
            Unsupported protocol '#{connection_protocol}'.

            Supported protocols are: #{SUPPORTED_CONNECTION_PROTOCOLS.join(" ")}
          EOM
          exit 1
        end
        true
      end

      def winrm_warn_no_ssl_verification
        return unless winrm?

        # REVIEWER NOTE
        # The original check from knife plugin did not include winrm_ssl_peer_fingerprint
        # Reference:
        # https://github.com/chef/knife-windows/blob/92d151298142be4a4750c5b54bb264f8d5b81b8a/lib/chef/knife/winrm_knife_base.rb#L271-L273
        # TODO Seems like we should also do a similar warning if ssh_verify_host == false
        if config_value(:ca_trust_file).nil? &&
            config_value(:winrm_no_verify_cert) &&
            config_value(:winrm_ssl_peer_fingerprint).nil?
          ui.warn <<~WARN
            * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
            SSL validation of HTTPS requests for the WinRM transport is disabled.
            HTTPS WinRM connections are still encrypted, but knife is not able
            to detect forged replies or spoofing attacks.

            To work around this issue you can use the flag `--winrm-no-verify-cert`
            or add an entry like this to your knife configuration file:

               # Verify all WinRM HTTPS connections
               knife[:winrm_no_verify_cert] = true

            You can also specify a ca_trust_file via --ca-trust-file,
            or the expected fingerprint of the target host's certificate
            via --winrm-ssl-peer-fingerprint.
          WARN
        end
      end

      # @return a configuration hash suitable for connecting to the remote
      # host via train
      def connection_opts
        return @connection_opts unless @connection_opts.nil?
        @connection_opts = {}
        @connection_opts.merge! base_opts
        @connection_opts.merge! host_verify_opts
        @connection_opts.merge! gateway_opts
        @connection_opts.merge! sudo_opts
        @connection_opts.merge! winrm_opts
        @connection_opts.merge! ssh_opts
        @connection_opts.merge! ssh_identity_opts
        @connection_opts
      end

      def winrm?
        connection_protocol == "winrm"
      end

      def ssh?
        connection_protocol == "ssh"
      end

      # Common configuration for all protocols
      def base_opts
        port = config_value(:connection_port,
                            knife_key_for_protocol(connection_protocol, :port))
        user = config_value(:connection_user,
                            knife_key_for_protocol(connection_protocol, :user))
        {}.tap do |opts|
          opts[:logger] = Chef::Log
          # We do not store password in Chef::Config, so only use CLI `config` here
          opts[:password] = config[:connection_password] if config.key?(:connection_password)
          opts[:user] = user if user
          opts[:max_wait_until_ready] = config_value(:max_wait) unless config_value(:max_wait).nil?
          # TODO - when would we need to provide rdp_port vs port?  Or are they not mutually exclusive?
          opts[:port] = port if port
        end
      end

      def host_verify_opts
        if winrm?
          { self_signed: config_value(:winrm_no_verify_cert) === true }
        elsif ssh?
          # Fall back to the old knife config key name for back compat.
          { verify_host_key: config_value(:ssh_verify_host_key,
                                          :host_key_verify, true) === true }
        else
          {}
        end
      end

      def ssh_opts
        opts = {}
        return opts if connection_protocol == "winrm"
        opts[:non_interactive] = true # Prevent password prompts from underlying net/ssh
        opts[:forward_agent] = (config_value(:ssh_forward_agent) === true)
        opts
      end

      def ssh_identity_opts
        opts = {}
        return opts if connection_protocol == "winrm"
        identity_file = config_value(:ssh_identity_file)
        if identity_file
          opts[:key_files] = [identity_file]
          # We only set keys_only based on the explicit ssh_identity_file;
          # someone may use a gateway key and still expect password auth
          # on the target.  Similarly, someone may have a default key specified
          # in knife config, but have provided a password on the CLI.

          # REVIEW NOTE: this is a new behavior. Originally, ssh_identity_file
          # could only be populated from CLI options, so there was no need to check
          # for this. We will also set keys_only to false only if there are keys
          # and no password.
          # If both are present, train(via net/ssh)  will prefer keys, falling back to password.
          # Reference: https://github.com/chef/chef/blob/master/lib/chef/knife/ssh.rb#L272
          opts[:keys_only] = config.key?(:connection_password) == false
        else
          opts[:key_files] = []
          opts[:keys_only] = false
        end

        gateway_identity_file = config_value(:ssh_gateway) ? config_value(:ssh_gateway_identity) : nil
        unless gateway_identity_file.nil?
          opts[:key_files] << gateway_identity_file
        end

        opts
      end

      def gateway_opts
        opts = {}
        if config_value(:ssh_gateway)
          split = config_value(:ssh_gateway).split("@", 2)
          if split.length == 1
            gw_host = split[0]
          else
            gw_user = split[0]
            gw_host = split[1]
          end
          gw_host, gw_port = gw_host.split(":", 2)
          # TODO - validate convertable port in config validation?
          gw_port = Integer(gw_port) rescue nil
          opts[:bastion_host] = gw_host
          opts[:bastion_user] = gw_user
          opts[:bastion_port] = gw_port
        end
        opts
      end

      # use_sudo - tells bootstrap to use the sudo command to run bootstrap
      # use_sudo_password - tells bootstrap to use the sudo command to run bootstrap
      #                     and to use the password specified with --password
      # TODO: I'd like to make our sudo options sane:
      # --sudo (bool) - use sudo
      # --sudo-password PASSWORD (default:  :password) - use this password for sudo
      # --sudo-options "opt,opt,opt" to pass into sudo
      # --sudo-command COMMAND sudo command other than sudo
      # REVIEW NOTE: knife bootstrap did not pull sudo values from Chef::Config,
      #              should we change that for consistency?
      def sudo_opts
        return {} if connection_protocol == "winrm"
        opts = { sudo: false }
        if config[:use_sudo]
          opts[:sudo] = true
          if config[:use_sudo_password]
            opts[:sudo_password] = config[:connection_password]
          end
          if config[:preserve_home]
            opts[:sudo_options] = "-H"
          end
        end
        opts
      end

      def winrm_opts
        return {} unless connection_protocol == "winrm"
        auth_method = config_value(:winrm_auth_method, :winrm_auth_method, "negotiate")
        opts = {
          winrm_transport: auth_method, # winrm gem and train calls auth method 'transport'
          winrm_basic_auth_only: config_value(:winrm_basic_auth_only) || false,
          ssl: config_value(:winrm_ssl) === true,
          ssl_peer_fingerprint: config_value(:winrm_ssl_peer_fingerprint),
        }

        if auth_method == "kerberos"
          opts[:kerberos_service] = config_value(:kerberos_service) if config_value(:kerberos_service)
          opts[:kerberos_realm] = config_value(:kerberos_realm) if config_value(:kerberos_service)
        end

        if config_value(:ca_trust_file)
          opts[:ca_trust_file] = config_value(:ca_trust_file)
        end

        opts[:operation_timeout] = config_value(:winrm_session_timeout) || 60

        opts
      end

      # Config overrides to force password auth.
      def force_ssh_password_opts(password)
        {
          password: password,
          non_interactive: false,
          keys_only: false,
          key_files: [],
          auth_methods: [:password, :keyboard_interactive],
        }
      end

      # Looks up configuration entries, first in the class member
      # `config` which contains options populated from CLI flags.
      # If the entry is not found there, Chef::Config[:knife][KEY]
      # is checked.
      #
      # knife_config_key should be specified if the knife config lookup
      # key is different from the CLI flag lookup key.
      #
      def config_value(key, knife_config_key = nil, default = nil)
        if config.key? key
          config[key]
        else
          lookup_key = knife_config_key || key
          if Chef::Config[:knife].key?(lookup_key)
            Chef::Config[:knife][lookup_key]
          else
            default
          end
        end
      end

      def upload_bootstrap(content)
        script_name = connection.windows? ? "bootstrap.bat" : "bootstrap.sh"
        remote_path = connection.normalize_path(File.join(connection.temp_dir, script_name))
        connection.upload_file_content!(content, remote_path)
        remote_path
      end

      # build the command string for bootrapping
      # @return String
      def bootstrap_command(remote_path)
        if connection.windows?
          "cmd.exe /C #{remote_path}"
        else
          "sh #{remote_path}"
        end
      end

      # To avoid cluttering the CLI options, some flags (such as port and user)
      # are shared between protocols.  However, there is still a need to allow the operator
      # to specify defaults separately, since they may not be the same values for different
      # protocols.

      # These keys are available in Chef::Config, and are prefixed with the protocol name.
      # For example, :user CLI option will map to :winrm_user and :ssh_user Chef::Config keys,
      # based on the connection protocol in use.
      def knife_key_for_protocol(protocol, option)
        "#{connection_protocol}_#{option}".to_sym
      end

      private

      # True if policy_name and run_list are both given
      def policyfile_and_run_list_given?
        run_list_given? && policyfile_options_given?
      end

      def run_list_given?
        !config[:run_list].nil? && !config[:run_list].empty?
      end

      def policyfile_options_given?
        !!config[:policy_name]
      end

      # True if one of policy_name or policy_group was given, but not both
      def incomplete_policyfile_options?
        (!!config[:policy_name] ^ config[:policy_group])
      end
    end
  end
end
