(in-package :coleslaw)

(defun app-path (path &rest args)
  "Take a relative PATH and return the corresponding pathname beneath coleslaw.
If ARGS is provided, use (apply 'format nil PATH ARGS) as the value of PATH."
  (merge-pathnames (apply 'format nil path args) coleslaw-conf:*basedir*))

(defun to-pathname (file parent)
  "Convert an iolib file-path back to a pathname."
  (merge-pathnames (file-path-namestring file) parent))

(defmacro do-files ((var path) &body body)
  "For each file under PATH, run BODY."
  `(iolib.os:mapdir (lambda (x)
                      (let ((,var (to-pathname x ,path)))
                        ,@body)) ,path))

(defun compile-blog ()
  (let ((staging #p"/tmp/coleslaw/"))
    ; TODO: More incremental compilation? Don't regen whole blog unnecessarily.
    (if (probe-file staging)
        (delete-files staging :recursive t)
        (ensure-directories-exist staging))
    (with-current-directory staging
      (let ((css-dir (app-path "themes/~a/css/" (theme *config*)))
            (static-dir (merge-pathnames "static/" (repo *config*))))
        (dolist (dir (list css-dir static-dir))
          (run-program "cp" `("-R" ,dir "."))))
      (render-posts)
      (render-indices))
    (deploy staging)))

(defun update-symlink (name target)
  "Update the symlink NAME to point to TARGET."
  (run-program "ln" (list "-sfn" (namestring target) name)))

(defun deploy (dir)
  "Deploy DIR, updating the .prev and .curr symlinks."
  (let ((new-build (app-path "generated/~a" (get-universal-time))))
    (run-program "mv" (list dir (namestring new-build)))
    (when (probe-file (app-path ".prev"))
      (delete-files (read-symlink (app-path ".prev")) :recursive t))
    (when (probe-file (app-path ".curr"))
      (update-symlink ".prev" (read-symlink (app-path ".curr"))))
    (update-symlink ".curr" new-build))
  (setf (last-published) (last-commit)))

(defun main ()
  (load-config)
  (compile-theme)
  (loop do (if (blog-update-p)
               (compile-blog)
               (sleep (interval *config*)))))