(in-package :cl)
(require :asdf)
(asdf:operate 'asdf:load-op 'drakma)

(defpackage :dns-admin (:use :cl :asdf))
(in-package :dns-admin)

(defparameter *conf-file* "/etc/dns-admin/options.lisp")
;;(defparameter *endpoint* "https://dns-admin.vcpfe.vzwops.com")
(defparameter *endpoint* "http://localhost:3000")
(defparameter *records* '(
                          (:name "www.meter.vzwops.com"
                           :ref "record:cname/ZG5zLmJpbmRfY25hbWUkLl9kZWZhdWx0LmNvbS52endvcHMubWV0ZXIud3d3:www.meter.vzwops.com/default")
                          (:name "core.meter.vzwops.com"
                           :ref "record:cname/ZG5zLmJpbmRfY25hbWUkLl9kZWZhdWx0LmNvbS52endvcHMubWV0ZXIuY29yZQ:core.meter.vzwops.com/default")
                          (:name "edn.meter.vzwops.com"
                           :ref "record:cname/ZG5zLmJpbmRfY25hbWUkLl9kZWZhdWx0LmNvbS52endvcHMubWV0ZXIuZWRu:edn.meter.vzwops.com/default")
                          (:name "capacity.meter.vzwops.com"
                           :ref "record:cname/ZG5zLmJpbmRfY25hbWUkLl9kZWZhdWx0LmNvbS52endvcHMubWV0ZXIuY2FwYWNpdHk:capacity.meter.vzwops.com/default")
                          (:name "capacity-edn.meter.vzwops.com"
                           :ref "record:cname/ZG5zLmJpbmRfY25hbWUkLl9kZWZhdWx0LmNvbS52endvcHMubWV0ZXIuY2FwYWNpdHktZWRu:capacity-edn.meter.vzwops.com/default")
                          ))

(defmacro with-cookie-jar (&body body)
  `(let ((cookie-jar (make-instance 'drakma:cookie-jar)))
     ,@body))

(defun drakma-request (url
                       cookie-jar
                       &key
                         (protocol :HTTP/1.1)
                         (method :get)
                         (content-type "application/x-www-form-urlencoded")
                         (user-agent :firefox)
                         (content nil)
                         (parameters nil)
                         (redirect t)
                         (auto-referer t)
                         (additional-headers nil)
                         (connection-timeout 120)
                         (verify nil)
                         (proxy nil)
                         (proxy-basic-authorization nil)
                         (basic-authorization nil))
  (drakma:http-request url
                       :cookie-jar cookie-jar
                       :protocol protocol
                       :method method
                       :content-type content-type
                       :parameters parameters
                       :content content
                       :user-agent user-agent
                       :redirect redirect
                       :auto-referer auto-referer
                       :connection-timeout connection-timeout
                       :additional-headers additional-headers
                       :verify verify
                       :proxy proxy
                       :proxy-basic-authorization proxy-basic-authorization
                       :basic-authorization basic-authorization
                       :close t))

(defun read-conf-file ()
  "Reads the data stored in the config file at location
`*conf-file*'."
  (when (probe-file *conf-file*)
    (with-open-file (input *conf-file* :direction :input)
      (read input))))

(defun read-creds ()
  (let ((conf (read-conf-file))
        username
        password)
    (setf username (getf conf :username))
    (setf password (getf conf :password))
    (values username password)))

(defun do-failover (target)
  (let ((retcode 0)
        (retmsg "OK"))
    (handler-case
        (multiple-value-bind (username password)
            (read-creds)
          (with-cookie-jar
            (loop for record in *records* do
              (format t "Setting ~a to ~a~%" (getf record :name) target)
              (multiple-value-bind (body status-code headers uri stream must-close reason)
                  (drakma-request (format nil "~a/dns/api/modify/post" *endpoint*)
                                  cookie-jar
                                  :method :post
                                  :basic-authorization `(,username ,password)
                                  :parameters `(("recordtype" . "cname")
                                                ("ref" . ,(getf record :ref))
                                                ("name" . ,(getf record :name))
                                                ("canonical" . ,(format nil "openbook-lb-vip-master-~a.meter.vzwops.com" target))))
                (declare (ignore headers uri stream must-close reason))
                (cond ((>= status-code 300)
                       (setf retcode 1)
                       (setf retmsg (format nil "Error response from dns-admin.~%Endpoint = [~a]~%Response = [~a]" (format nil "~a/dns/modify/submit" *endpoint*) body)))
                      (t
                       (format t "~a~%" body)))))))
      (error (e)
        (progn
          (setf retcode 1)
          (setf retmsg (format nil "An error occurred. Error: ~a" e)))))
    (values retcode retmsg)))

(defun run (&optional target-override)
  (let ((target (or target-override (car (last sb-ext:*posix-argv*))))
        (retcode 0)
        (retmsg "OK"))
    (cond ((not (find target '("rocklin" "twinsburg") :test 'string=))
           (setf retcode 1)
           (setf retmsg "Invalid target specified. Must be 'rocklin' or 'twinsburg'."))
          (t
           (multiple-value-bind (code msg)
               (do-failover target)
             (setf retcode code)
             (setf retmsg msg))))
    (format t "~a" retmsg)
    (sb-ext:exit :code retcode)))