;;;; Command line options.

;;; Copyright (c) 2021–2022  Teddy Wing
;;;
;;; This file is part of Extreload.
;;;
;;; Extreload is free software: you can redistribute it and/or modify
;;; it under the terms of the GNU General Public License as published by
;;; the Free Software Foundation, either version 3 of the License, or
;;; (at your option) any later version.
;;;
;;; Extreload is distributed in the hope that it will be useful,
;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with Extreload. If not, see <https://www.gnu.org/licenses/>.


(in-package :extreload)

;; Available command line options.
(opts:define-opts
  (:name :socket-url
         :description "DevTools protocol WebSocket URL"
         :long "socket-url"
         :arg-parser #'identity
         :meta-var "SOCKET_URL")
  (:name :reload-current-tab
         :description "pass this to reload the active Chrome tab"
         :long "reload-current-tab")
  (:name :debug
         :description "print debug output"
         :long "debug")
  (:name :help
         :description "print this help menu"
         :short #\h
         :long "help")
  (:name :version
         :description "show the program version"
         :short #\V
         :long "version"))

(defmacro when-option ((options option) &body body)
  "When `option` is present in `options`, run `body`."
  `(let ((value (getf ,options ,option)))
     (when value
       ,@body)))

(defun exit-with-error (condition exit-code)
  "Print the error associated with `condition` on standard error, then exit
with code `exit-code`."
  (format *error-output* "error: ~a~%" condition)

  (opts:exit exit-code))

(defun handle-option-error (condition)
  "Handle errors related to command line options. Prints the error specified by
`condition` and exits with EX_USAGE."
  (exit-with-error condition sysexits:+usage+))

(defconstant *version* (asdf:component-version (asdf:find-system :extreload)))

(defun parse-options ()
  "Parse command line options."
  (multiple-value-bind (options free-args)
    (handler-bind
      ((opts:unknown-option #'handle-option-error)
       (opts:missing-arg #'handle-option-error)
       (opts:arg-parser-failed #'handle-option-error)
       (opts:missing-required-option #'handle-option-error))

      (opts:get-opts))

    (when-option (options :help)
      (opts:describe
        :usage-of "extreload"
        :args "EXTENSION_ID...")

      (opts:exit sysexits:+usage+))

    (when-option (options :version)
      (format t "~a~%" *version*)

      (opts:exit sysexits:+ok+))

    (when (null (getf options :socket-url))
        (format *error-output* "error: '--socket-url' is required~%")

        (opts:exit sysexits:+usage+))

    ;; Error if no extension IDs were given.
    (when (null free-args)
      (format *error-output* "error: missing extension IDs~%")

      (opts:exit sysexits:+usage+))

    (make-config :socket-url (getf options :socket-url)
                 :reload-current-tab (getf options :reload-current-tab)
                 :debug-output (getf options :debug)
                 :extension-ids free-args)))