;;; polymode-test-utils.el --- Testing utilities for polymode -*- lexical-binding: t -*-
;;
;; Copyright (C) 2018, Vitalie Spinu
;; Author: Vitalie Spinu
;; URL: https://github.com/vspinu/polymode
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;; This file is *NOT* part of GNU Emacs.
;;
;; This program 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, or
;; (at your option) any later version.
;;
;; This program 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 this program; see the file COPYING.  If not, write to
;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth
;; Floor, Boston, MA 02110-1301, USA.
;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;
;;
;;; Commentary:
;;
;; This file should be loaded only in tests.
;;
;;; Code:

(setq eieio-backward-compatibility nil)

(require 'ert)
(require 'polymode)
(eval-when-compile
  (require 'cl-lib))

;; (require 'font-lock)
;; (global-font-lock-mode t)
;; (add-hook 'after-change-major-mode-hook #'global-font-lock-mode-enable-in-buffers)
;; (message "ACMH: %s  GFL:%s" after-change-major-mode-hook global-font-lock-mode)

(setq ert-batch-backtrace-right-margin 200)
(defvar pm-verbose (getenv "PM_VERBOSE"))

(defvar pm-test-current-change-set nil)
(defun pm-test-get-file (name)
  "Find the file with NAME from inside a poly-xyz repo.
Look into tests/input directory then in samples directory."
  (let ((files (list (expand-file-name (format "./tests/input/%s" name) default-directory)
                     (expand-file-name (format "./input/%s" name) default-directory)
                     (expand-file-name (format "./samples/%s" name) default-directory)
                     (expand-file-name (format "../samples/%s" name) default-directory))))
    (or (cl-loop for f in files
                 if (file-exists-p f) return f)
        (error "No file with name '%s' found in '%s'" name default-directory))))

(defun pm-test-matcher (string span-alist matcher &optional dry-run)
  (with-temp-buffer
    (insert string)
    (goto-char (point-min))
    (let (prev-span)
      (when dry-run
        (message "("))
      (while (not (eobp))
        (if dry-run
            (let ((span (funcall matcher)))
              (unless (equal prev-span span)
                (setq prev-span span)
                (message " (%d . %S)" (nth 1 span) span)))
          (let* ((span (funcall matcher))
                 (sbeg (nth 1 span))
                 (ref-span (alist-get sbeg span-alist)))
            (unless (equal span ref-span)
              (ert-fail (list :pos (point) :span span :ref-span ref-span)))
            (when (and prev-span
                       (not (or (eq (nth 1 prev-span) sbeg)
                                (eq (nth 2 prev-span) sbeg))))
              (ert-fail (list :pos (point) :span span :prev-span prev-span)))
            (setq prev-span span)))
        (forward-char 1))
      (when dry-run
        (message ")"))
      nil)))

(defmacro pm-test-run-on-string (mode string &rest body)
  "Run BODY in a temporary buffer containing STRING in MODE.
MODE is a quoted symbol."
  (declare (indent 1) (debug (form form body)))
  `(let ((buf "*pm-test-string-buffer*"))
     (when (get-buffer buf)
       (kill-buffer buf))
     (with-current-buffer (get-buffer-create buf)
       (insert (substring-no-properties ,string))
       (funcall ,mode)
       (setq-default indent-tabs-mode nil)
       (goto-char (point-min))
       (font-lock-ensure)
       ,@body
       (current-buffer))))

(defmacro pm-test-run-on-file (mode file-name &rest body)
  "Run BODY in a buffer with the content of FILE-NAME in MODE."
  (declare (indent 2) (debug (sexp sexp body)))
  (let ((pre-form (when (eq (car body) :pre-form)
                    (prog1 (cadr body)
                      (setq body (cddr body))))))
    `(let ((poly-lock-allow-background-adjustment nil)
           ;; snapshot it during the expansion to be able to run polymode-organization tests
           (file ,(pm-test-get-file file-name))
           (pm-extra-span-info nil)
           (buf "*pm-test-file-buffer*"))
       (when (get-buffer buf)
         (kill-buffer buf))
       (with-current-buffer (get-buffer-create buf)
         (when pm-verbose
           (message "\n===================  testing %s =======================" file))
         (switch-to-buffer buf)
         (insert-file-contents file)
         (remove-hook 'text-mode-hook 'flyspell-mode) ;; triggers "too much reentrancy" error
         (let ((inhibit-message t))
           (funcall-interactively ',mode))
         ;; (flyspell-mode -1) ;; triggers "too much reentrancy" error
         (goto-char (point-min))
         ,pre-form
         (font-lock-ensure)
         (goto-char (point-min))
         (save-excursion
           (let ((font-lock-mode t))
             (pm-map-over-spans
              (lambda (_)
                (setq font-lock-mode t)
                ;; This is not picked up because font-lock is nil on innermode
                ;; initialization. Don't know how to fix this more elegantly.
                ;; For now our tests are all with font-lock, so we are fine for
                ;; now.
                (setq-local poly-lock-allow-fontification t)
                ;; font-lock is not activated in batch mode
                (poly-lock-mode t)
                ;; redisplay is not triggered in batch and often it doesn't trigger
                ;; fontification in X either (waf?)
                (add-hook 'after-change-functions #'pm-test-invoke-fontification t t))
              (point-min) (point-max))))
         (font-lock-ensure)
         ,@body
         (current-buffer)))))

(defun pm-test-span (span &optional allow-failed-faces)
  ;; head/tail is usually highlighted incorrectly by host modes when only head
  ;; is in the buffer, so we just skip those head-tails which have
  ;; :head/tail-mode 'host
  (when (eq (car span) (pm-true-span-type *span*))
    (let* ((poly-lock-allow-background-adjustment nil)
           (sbeg (nth 1 span))
           (send (nth 2 span))
           (smode major-mode)
           (stext (buffer-substring-no-properties sbeg send))
           ;; other buffer
           (obuf (pm-test-run-on-string smode stext))
           (opos 1))
      (when pm-verbose
        (message "---- testing %s ----" (pm-format-span span t)))
      (while opos
        (let* ((pos (1- (+ opos sbeg)))
               (face (get-text-property pos 'face))
               (oface (get-text-property opos 'face obuf)))
          (unless (or
                   ;; in markdown fence regexp matches end of line; it's likely
                   ;; to be a common mismatch between host mode and polymode,
                   ;; thus don't check first pos if it's a new line
                   (and (= opos 1)
                        (with-current-buffer obuf
                          (eq (char-after 1) ?\n)))
                   (member face allow-failed-faces)
                   (equal face oface))
            (let ((data
                   (append
                    (when pm-test-current-change-set
                      (list :change pm-test-current-change-set))
                    (list
                     ;; :af poly-lock-allow-fontification
                     ;; :fl font-lock-mode
                     :face face
                     :oface oface
                     :pos pos
                     :opos opos
                     :line (progn (goto-char pos)
                                  (buffer-substring-no-properties (point-at-bol) (point-at-eol)))
                     :oline (with-current-buffer obuf
                              (goto-char opos)
                              (buffer-substring-no-properties (point-at-bol) (point-at-eol)))
                     :mode smode))))
              (ert-fail data)))
          (setq opos (next-single-property-change opos 'face obuf)))))))

(defun pm-test-spans (&optional allow-failed-faces)
  "Execute `pm-test-span' for every span in the buffer.
ALLOW-FAILED-FACES should be a list of faces on which failures
are OK."
  (save-excursion
    (pm-map-over-spans
     (lambda (span) (pm-test-span span allow-failed-faces)))))

(defun pm-test-goto-loc (loc)
  "Go to LOC and switch to polymode indirect buffer.
LOC can be either
  - a number giving position in the buffer
  - regexp to search for from ‘point-min’
  - a cons of the form (ROW . COL)
In the last case ROW can be either a number or a regexp to search
for and COL either a column number or symbols beg or end
indicating beginning or end of the line. When COL is nil, goto
indentation."
  (cond
   ((numberp loc)
    (goto-char loc))
   ((stringp loc)
    (goto-char (point-min))
    (re-search-forward loc))
   ((consp loc)
    (goto-char (point-min))
    (let ((row (car loc)))
      (goto-char (point-min))
      (cond
       ((stringp row)
        (re-search-forward row))
       ((numberp row)
        (forward-line (1- row)))
       (t (error "Invalid row spec %s" row))))
    (let* ((col (cdr loc))
           (col (if (listp col)
                    (car col)
                  col)))
      (cond
       ((numberp col)
        (forward-char col))
       ((eq col 'end)
        (end-of-line))
       ((eq col 'beg)
        (beginning-of-line))
       ((null col)
        (back-to-indentation))
       (t (error "Invalid col spec %s" col))))))
  (when polymode-mode
    ;; pm-set-buffer would do for programs but not for interactive debugging
    (pm-switch-to-buffer (point))))

(defun pm-test-goto-loc-other-window ()
  "Utility to navigate to loc at point in other buffer.
LOC is as in `pm-test-goto-loc'."
  (interactive)
  (let ((loc (or (sexp-at-point)
                 (read--expression "Loc: "))))
    (when (symbolp loc)
      (setq loc (string-to-number (thing-at-point 'word))))
    (other-window 1)
    (pm-test-goto-loc loc)))

(defun pm-test-invoke-fontification (&rest _ignore)
  "Mimic calls to fontification functions by redisplay.
Needed because redisplay is not triggered in batch mode."
  (when fontification-functions
    (save-restriction
      (widen)
      (save-excursion
        (let (pos)
          (while (setq pos (text-property-any (point-min) (point-max) 'fontified nil))
            (let ((inhibit-modification-hooks t)
                  (inhibit-redisplay t))
              (when pm-verbose
                (message "after change fontification-functions (%s)" pos))
              (run-hook-with-args 'fontification-functions pos))))))))

(defmacro pm-test-poly-lock (mode file &rest change-sets)
  "Test font-lock for MODE and FILE.
CHANGE-SETS is a collection of forms of the form (NAME-LOC &rest
BODY). NAME-LOC is a list of the form (NAME LOCK) where NAME is a
symbol, LOC is the location as in `pm-test-goto-loc'. Before and
after execution of the BODY ‘undo-boundary’ is set and after the
execution undo is called once. After each change-set
`pm-test-span' on the whole file is run."
  (declare (indent 2)
           (debug (sexp sexp &rest ((name sexp) &rest form))))
  `(kill-buffer
    (pm-test-run-on-file ,mode ,file
      ;; (pm-test-spans)
      (dolist (cset ',change-sets)
        (let ((pm-test-current-change-set (caar cset)))
          (setq pm-extra-span-info (caar cset))
          (undo-boundary)
          (pm-test-goto-loc (nth 1 (car cset)))
          (eval (cons 'progn (cdr cset)))
          (undo-boundary)
          (pm-test-spans)
          (let ((inhibit-message (not pm-verbose)))
            (undo)))))))

(defun pm-test--run-indentation-tests ()
  "Run an automatic batch of indentation tests.
First run `indent-line' on every line and compare original and
indented version. Then compute stasrt,middle and end points of
each span and call `indent-region' on a shuffled set of these
points."
  (goto-char (point-min))
  (set-buffer-modified-p nil)
  (while (not (eobp))
    (let ((orig-line (buffer-substring-no-properties (point-at-eol) (point-at-bol))))
      (unless (string-match-p "no-indent-test" orig-line)
        (undo-boundary)
        (pm-indent-line-dispatcher)
        (unless (equal orig-line (buffer-substring-no-properties (point-at-eol) (point-at-bol)))
          (undo-boundary)
          (pm-switch-to-buffer (point))
          (ert-fail (list :pos (point) :line (line-number-at-pos)
                          :indent-line (buffer-substring-no-properties (point-at-bol) (point-at-eol)))))))
    (forward-line 1))
  (let (points1 points2)
    (pm-map-over-spans (lambda (span) (push (/ (+ (nth 1 span) (nth 2 span)) 2) points1)))
    (random "some-seed")
    (let ((len (length points1)))
      (dotimes (_ len)
        (push (elt points1 (random len)) points2)))
    (let ((points2 (reverse points1)))
      (cl-mapc
       (lambda (beg end)
         (unless (= beg end)
           (let ((orig-region (buffer-substring-no-properties beg end)))
             (unless (string-match-p "no-indent-test" orig-region)
               (undo-boundary)
               (indent-region beg end)
               (unless (equal orig-region (buffer-substring-no-properties beg end))
                 (undo-boundary)
                 (pm-switch-to-buffer beg)
                 (ert-fail `(indent-region ,beg ,end)))))))
       points1 points2))))

(defmacro pm-test-indentation (mode file)
  "Test indentation for MODE and FILE."
  `(pm-test-run-on-file ,mode ,file
     (undo-boundary)
     (let ((inhibit-message t))
       (unwind-protect
           (pm-test--run-indentation-tests)
         (undo-boundary)))))

(provide 'polymode-test-utils)
;;; polymode-test.el ends here