clark/lisp/clark.lisp

;; Copyright (C) 2013  Tom Willemsen <tom at ryuslash dot org>

;; This file is part of CLark

;; CLark 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.

;; CLark 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 CLark. If not, see <http://www.gnu.org/licenses/>.

;;; Code:

(in-package :clark)

(defvar *db* nil
  "The database connection.")

(defvar *help-messages* nil
  "Help texts for commands.")

(defvar *max-command-name-length* 0
  "Length of the longest command name.")

(defvar *script* nil
  "Whether or not to output in a machine-readable format.")

(define-condition exiting ()
  ((exit-code :initform 0 :initarg :code :reader exit-code)))

(defmacro call-command (name &rest args)
  (let ((command-name (make-command-name (symbol-name name))))
    `(,command-name ,@args)))

(defmacro defcommand (name (&rest args) sdoc ldoc &body body)
  "Define a new command usable on the command-line."
  (let* ((sname (string-downcase (symbol-name name)))
         (command-name (make-command-name (symbol-name name))))
    `(progn
       (defun ,command-name (,@args)
         ,sdoc
         ,@body)
       (setf *help-messages*
             (nconc *help-messages* '((,sname ,sdoc ,ldoc)))
             *max-command-name-length*
             (max *max-command-name-length* (length ,sname)))
       (export ',command-name))))

(defmacro with-error-and-help (code cmd fmt &rest args)
  "Call `with-error-status' with CODE, format FMT with ARGS and call
the help command."
  `(with-error-status ,code
     (format t ,fmt ,@args)
     (call-command help ,cmd)))

(defmacro with-error-status (code &body body)
  "Bind `*exit-status*' to CODE, `*standard-output*' to
`*error-output*' and execute BODY."
  `(let ((*standard-output* *error-output*)
         (exit-status ,code))
     ,@body
     (when (> exit-status 0)
       (signal 'exiting :code exit-status))))

(defparameter version "0.1.1"
  "Clark's version.")

(defun add-tags (url-or-id tags)
  "Add tags to the bookmark_tag table and possibly to tag."
  (when url-or-id
    (if (integerp url-or-id)
        (map nil (lambda (tag)
                   (let ((tag-id (handler-case (insert-tag tag)
                                   (sqlite-error () (get-tag-id tag)))))
                     (insert-bookmark-tag url-or-id tag-id))) tags)
        (add-tags (get-bookmark-id url-or-id) tags))))

(defun clear-tags (url-or-id)
  "Remove all tags from the bookmark URL."
  (when url-or-id
    (if (integerp url-or-id)
        (delete-tags url-or-id)
        (clear-tags (get-bookmark-id url-or-id)))))

(defun ensure-db-exists (name)
  "Connect to the database, possibly creating it."
  (let ((db-exists (probe-file name)))
    (setf *db* (connect name))
    (unless db-exists
      (create-table-bookmark)
      (create-table-tag)
      (create-table-bookmark_tag))))

(defun get-db-location ()
  "Get the location of the database."
  (let ((xdg (sb-ext:posix-getenv "XDG_DATA_HOME"))
        (home (sb-ext:posix-getenv "HOME")))
    (pathname
     (apply 'concatenate 'string
            (or xdg home)
            (unless xdg "/.local/share")
            '("/clark/bookmarks.db")))))

(defun get-rc-location ()
  "Get the location of the RC file."
  (let ((xdg (sb-ext:posix-getenv "XDG_CONFIG_HOME"))
        (home (sb-ext:posix-getenv "HOME")))
    (pathname
     (apply 'concatenate 'string
            (or xdg home)
            (unless xdg "/.config")
            '("/clark/rc.lisp")))))

(defun help-message ()
  (format t (concatenate
             'string
             "Usage: clark [options] [<command> [<options> ...]]~%"
             "~%"
             "Possible options:~%"
             "~%"
             "  --script  Output in a machine-readable format.~%"
             "~%"
             "Possible commands:~%"
             "~%"))
  (map nil (lambda (hlp)
             (destructuring-bind (name short long) hlp
               (declare (ignore long))
               (format t "  ~vA  ~A~%" *max-command-name-length*
                       name short))) *help-messages*)
  (format t "~%~A~%"
          (concatenate 'string "Use `clark help <command>' to get more "
                       "information on a command.")))

(defun load-db ()
  "Load the database."
  (let ((db-location (get-db-location)))
    (ensure-directories-exist db-location)
    (ensure-db-exists db-location)))

(defun load-rc ()
  "Load the RC file."
  (let ((*package* (in-package :clark)))
    (load (get-rc-location) :if-does-not-exist nil)))

(eval-when (:compile-toplevel :load-toplevel :execute)
  (defun make-command-name (base)
    "Turn BASE into the name of a possible command."
    (intern (concatenate 'string (string-upcase base) "-COMMAND")
            :clark)))

(defun parse-args (args)
  "Parse command-line arguments ARGS.

The executable name should already have been removed."
  (loop while (and args (char= (char (car args) 0) #\-))
     do (case (intern (string-upcase (string-left-trim "-" (car args)))
                      :clark)
          (script (setf *script* t args (cdr args)))
          (t (with-error-and-help
                 1 "help" "Unknown option: ~a~%" (car args)))))
  (if args
      (let ((cmd-name (make-command-name (car args))))
        (if (fboundp cmd-name)
            (handler-case (apply cmd-name (cdr args))
              (sb-int:simple-program-error (err)
                (if (string-equal (format nil "~A" err)
                                  "invalid number of arguments" :end1 27)
                    (with-error-and-help
                        1 (car args) "Wrong number of arguments given.~%")
                    (signal err))))
            (with-error-and-help
                1 "help" "Unknown command: ~A~%" (car args))))
      (map nil #'print-bookmark (bookmark-list))))

(defun print-bookmark (bm)
  "Print information about bookmark BM.

BM should be a list containing the url, name and description of the
bookmark."
  (destructuring-bind (url name description) bm
    (if *script*
        (format t "~A~A~A" url name description)
        (format t "~A~%  ~A~%  ~A~%~%" url name description))))

(defun clark (args)
  "Main function.

Connect to the database, parse command-line arguments, execute and
then disconnect."
  (load-rc)
  (load-db)
  (handler-case
      (unwind-protect (parse-args (cdr args))
        (disconnect *db*))
    (exiting (c) (sb-ext:exit :code (exit-code c)))))