;;; test-org-drill-entry-p.el --- Tests for org-drill-entry-p function

;;; Commentary:
;; Unit tests for org-drill-entry-p, which determines if point is at a
;; drill entry heading (not a subheading within a drill entry).
;;
;; The function checks for the drill tag at the current heading only,
;; not inherited tags. Use org-drill-part-of-drill-entry-p for inherited tags.

;;; Code:

(require 'ert)
(require 'assess)
(require 'org-drill)

;;; Test Data

(defconst test-org-drill-entry-p-simple-entry
  "* Heading with drill tag :drill:

Body content here."
  "Simple drill entry with drill tag on main heading.")

(defconst test-org-drill-entry-p-no-tag
  "* Heading without drill tag

Body content here."
  "Heading without any drill tag.")

(defconst test-org-drill-entry-p-nested-entry
  "* Parent heading :drill:

Parent content.

** Child heading

Child content."
  "Drill entry with nested child heading.")

(defconst test-org-drill-entry-p-multiple-tags
  "* Heading :drill:important:review:

Body with multiple tags."
  "Drill entry with multiple tags including drill.")

(defconst test-org-drill-entry-p-custom-tag
  "* Heading :customtag:

Body with custom tag."
  "Heading with custom tag (not drill).")

;;; Helper Functions

(defun test-org-drill-entry-p--with-org-buffer (content callback)
  "Execute CALLBACK in temporary org-mode buffer with CONTENT."
  (with-temp-buffer
    (org-mode)
    (insert content)
    (goto-char (point-min))
    (funcall callback)))

;;; Normal Cases

(ert-deftest test-org-drill-entry-p-normal-valid-tag-returns-true ()
  "Test that heading with drill tag is identified as drill entry."
  (test-org-drill-entry-p--with-org-buffer
   test-org-drill-entry-p-simple-entry
   (lambda ()
     (should (org-drill-entry-p)))))

(ert-deftest test-org-drill-entry-p-normal-no-tag-returns-nil ()
  "Test that heading without drill tag returns nil."
  (test-org-drill-entry-p--with-org-buffer
   test-org-drill-entry-p-no-tag
   (lambda ()
     (should-not (org-drill-entry-p)))))

(ert-deftest test-org-drill-entry-p-normal-multiple-tags-returns-true ()
  "Test that heading with multiple tags including drill is identified."
  (test-org-drill-entry-p--with-org-buffer
   test-org-drill-entry-p-multiple-tags
   (lambda ()
     (should (org-drill-entry-p)))))

(ert-deftest test-org-drill-entry-p-normal-at-parent-heading-returns-true ()
  "Test that function works when point is at parent drill heading."
  (test-org-drill-entry-p--with-org-buffer
   test-org-drill-entry-p-nested-entry
   (lambda ()
     ;; Point should be at parent heading after goto-char (point-min)
     (should (org-drill-entry-p)))))

;;; Boundary Cases

(ert-deftest test-org-drill-entry-p-boundary-at-child-heading-returns-nil ()
  "Test that child heading of drill entry returns nil.
Only the heading with the actual drill tag should return true."
  (test-org-drill-entry-p--with-org-buffer
   test-org-drill-entry-p-nested-entry
   (lambda ()
     ;; Move to child heading
     (re-search-forward "^\\*\\* Child heading")
     (beginning-of-line)
     (should-not (org-drill-entry-p)))))

(ert-deftest test-org-drill-entry-p-boundary-empty-heading-no-tag-returns-nil ()
  "Test that empty heading without tags returns nil."
  (test-org-drill-entry-p--with-org-buffer
   "* Empty heading\n"
   (lambda ()
     (should-not (org-drill-entry-p)))))

(ert-deftest test-org-drill-entry-p-boundary-heading-with-only-whitespace-tag ()
  "Test heading with whitespace around tags."
  (test-org-drill-entry-p--with-org-buffer
   "* Heading   :drill:   \n\nContent"
   (lambda ()
     (should (org-drill-entry-p)))))

(ert-deftest test-org-drill-entry-p-boundary-custom-tag-not-drill ()
  "Test that custom tag (not drill) returns nil."
  (test-org-drill-entry-p--with-org-buffer
   test-org-drill-entry-p-custom-tag
   (lambda ()
     (should-not (org-drill-entry-p)))))

(ert-deftest test-org-drill-entry-p-boundary-drill-substring-in-other-tag ()
  "Test that drill as substring of another tag does not match.
Tag 'drilling' should not be identified as drill entry."
  (test-org-drill-entry-p--with-org-buffer
   "* Heading :drilling:\n\nContent"
   (lambda ()
     (should-not (org-drill-entry-p)))))

(ert-deftest test-org-drill-entry-p-boundary-case-sensitive-tag ()
  "Test that drill tag matching is case-sensitive.
Tag 'DRILL' should not match 'drill'."
  (test-org-drill-entry-p--with-org-buffer
   "* Heading :DRILL:\n\nContent"
   (lambda ()
     ;; org-mode tags are case-sensitive by default
     (should-not (org-drill-entry-p)))))

;;; Error Cases

(ert-deftest test-org-drill-entry-p-error-point-in-body-text ()
  "Test behavior when point is in body text, not at heading.
Function should check current heading context."
  (test-org-drill-entry-p--with-org-buffer
   test-org-drill-entry-p-simple-entry
   (lambda ()
     ;; Move to body text
     (re-search-forward "Body content")
     (beginning-of-line)
     ;; Even though we're in a drill entry's body, org-drill-entry-p
     ;; checks the current heading when point is in body
     (should (org-drill-entry-p)))))

(ert-deftest test-org-drill-entry-p-error-empty-buffer ()
  "Test behavior in empty buffer.
Should not error, just return nil."
  (with-temp-buffer
    (org-mode)
    (should-not (org-drill-entry-p))))

(ert-deftest test-org-drill-entry-p-error-buffer-without-headings ()
  "Test behavior in buffer with only text, no headings."
  (test-org-drill-entry-p--with-org-buffer
   "Just some text without any headings."
   (lambda ()
     (should-not (org-drill-entry-p)))))

(ert-deftest test-org-drill-entry-p-error-malformed-heading ()
  "Test behavior with malformed heading syntax.
Single asterisk should still work as heading."
  (test-org-drill-entry-p--with-org-buffer
   "* Malformed :drill:\nNo blank line before content"
   (lambda ()
     (should (org-drill-entry-p)))))

;;; Aggressive Boundary Cases

(ert-deftest test-org-drill-entry-p-boundary-very-long-tag-name ()
  "Test drill tag with very long name (edge case).
Tag name length should not cause issues."
  (let* ((long-tag (make-string 200 ?d))
         (content (format "* Heading :%s:\n\nContent\n" long-tag)))
    (test-org-drill-entry-p--with-org-buffer
     content
     (lambda ()
       ;; Should not match 'drill' tag
       (should-not (org-drill-entry-p))))))

(ert-deftest test-org-drill-entry-p-boundary-many-tags ()
  "Test heading with many tags including drill.
Should still correctly identify drill tag among many others."
  (let ((content "* Heading :tag1:tag2:tag3:drill:tag4:tag5:tag6:tag7:tag8:tag9:tag10:\n\nContent\n"))
    (test-org-drill-entry-p--with-org-buffer
     content
     (lambda ()
       (should (org-drill-entry-p))))))

(ert-deftest test-org-drill-entry-p-boundary-unicode-in-heading ()
  "Test heading with unicode characters and drill tag.
Unicode should not interfere with tag detection."
  (let ((content "* Café München 北京 :drill:\n\nUnicode content 日本語\n"))
    (test-org-drill-entry-p--with-org-buffer
     content
     (lambda ()
       (should (org-drill-entry-p))))))

(ert-deftest test-org-drill-entry-p-boundary-deep-nesting ()
  "Test drill tag detection at deep nesting level.
Should work at any heading level."
  (let ((content "* Level 1\n** Level 2\n*** Level 3\n**** Level 4\n***** Level 5 :drill:\n\nDeep content\n"))
    (test-org-drill-entry-p--with-org-buffer
     content
     (lambda ()
       ;; Navigate to deeply nested heading
       (re-search-forward "Level 5")
       (beginning-of-line)
       (should (org-drill-entry-p))))))

(ert-deftest test-org-drill-entry-p-boundary-tag-with-numbers ()
  "Test that tags containing 'drill' substring but with numbers don't match.
drill123 should not be recognized as drill tag."
  (let ((content "* Heading :drill123:\n\nContent\n"))
    (test-org-drill-entry-p--with-org-buffer
     content
     (lambda ()
       (should-not (org-drill-entry-p))))))

(ert-deftest test-org-drill-entry-p-boundary-drill-at-tag-boundary ()
  "Test drill tag at beginning and end of tag list."
  (let ((content1 "* Heading :drill:other:tags:\n\nContent\n")
        (content2 "* Heading :other:tags:drill:\n\nContent\n"))
    ;; drill at start
    (test-org-drill-entry-p--with-org-buffer
     content1
     (lambda ()
       (should (org-drill-entry-p))))
    ;; drill at end
    (test-org-drill-entry-p--with-org-buffer
     content2
     (lambda ()
       (should (org-drill-entry-p))))))

(ert-deftest test-org-drill-entry-p-boundary-special-chars-in-heading ()
  "Test heading with special characters and drill tag.
Special chars should not break tag parsing."
  (let ((content "* Heading with @#$%^&*() special chars :drill:\n\nContent\n"))
    (test-org-drill-entry-p--with-org-buffer
     content
     (lambda ()
       (should (org-drill-entry-p))))))

(ert-deftest test-org-drill-entry-p-boundary-very-long-heading-line ()
  "Test heading with very long title text.
Long heading should not affect tag detection."
  (let* ((long-title (make-string 1000 ?x))
         (content (format "* %s :drill:\n\nContent\n" long-title)))
    (test-org-drill-entry-p--with-org-buffer
     content
     (lambda ()
       (should (org-drill-entry-p))))))

(provide 'test-org-drill-entry-p)
;;; test-org-drill-entry-p.el ends here