;;; +django-tests.el -*- lexical-binding: t; -*-

(require 'projectile)
(require 'python)
(require 'subr-x)

(defun django--project-root ()
  (or (projectile-project-root)
      (user-error "Not in a Projectile project")))

(defun django--module-from-file (file root)
  (let* ((rel (file-relative-name file root))
         (no-ext (file-name-sans-extension rel)))
    (replace-regexp-in-string "/" "." no-ext)))

(defun django--def-name-at-point ()
  (save-excursion
    (when (ignore-errors (python-nav-beginning-of-defun) t)
      (when (looking-at (rx bol (* space) "def" (+ space)
                            (group (+ (or word ?_))) (* space) "("))
        (match-string-no-properties 1)))))

(defun django--enclosing-class-name ()
  (save-excursion
    (let ((found nil)
          (limit (point-min)))
      (while (and (not found) (> (point) limit))
        (python-nav-beginning-of-statement)
        (when (looking-at (rx bol (* space) "class" (+ space)
                              (group (+ (or word ?_)))))
          (setq found (match-string-no-properties 1)))
        (condition-case _err
            (python-nav-backward-block)
          (error (goto-char limit))))
      found)))

(defun django--selector-at-point ()
  (let ((fn (django--def-name-at-point))
        (cls (django--enclosing-class-name)))
    (cond
     ((and fn (string-prefix-p "test_" fn))
      (if cls (format "%s.%s" cls fn) fn))
     (cls cls)
     (t nil))))

(defun django-run-tests (&optional module selector)
  (interactive)
  (let* ((module-part (or module ""))
         (selector-part (if selector (concat "." selector) ""))
         (param (string-trim (concat module-part selector-part)))
         (command (format "python manage.py test %s" param)))
    (message "Running command: %s" command)
    (projectile-run-async-shell-command-in-root command "*Django tests*")))

(defun django-run-test-at-point ()
  (interactive)
  (let* ((root (django--project-root))
         (file (or (buffer-file-name) (user-error "Buffer is not visiting a file")))
         (module (django--module-from-file file root))
         (sel (django--selector-at-point)))
    (django-run-tests module sel)))

(defun django-run-tests-for-current-file ()
  (interactive)
  (let* ((root (django--project-root))
         (file (or (buffer-file-name) (user-error "Buffer is not visiting a file")))
         (module (django--module-from-file file root)))
    (django-run-tests module nil)))

(provide '+django-tests)