;;; test-pearl-surface.el --- Tests for surfacing the active buffer -*- lexical-binding: t; -*-

;; Copyright (C) 2026 Craig Jennings

;; Author: Craig Jennings <c@cjennings.net>

;; 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 of the License, 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.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; Tests for `pearl--surface-buffer': bring the active org buffer to a window
;; after a command updates it, gated on `pearl-surface-buffer', focus-following
;; gated on `pearl-surface-select-window', and skipped when the buffer is dead
;; or already visible.

;;; Code:

(require 'test-bootstrap (expand-file-name "test-bootstrap.el"))
(require 'cl-lib)

(ert-deftest test-pearl-surface-buffer-disabled-is-noop ()
  "With `pearl-surface-buffer' nil, nothing is displayed."
  (let ((pearl-surface-buffer nil) (shown nil))
    (cl-letf (((symbol-function 'display-buffer) (lambda (&rest _) (setq shown t)))
              ((symbol-function 'pop-to-buffer) (lambda (&rest _) (setq shown t))))
      (with-temp-buffer
        (pearl--surface-buffer (current-buffer))
        (should-not shown)))))

(ert-deftest test-pearl-surface-buffer-shows-when-buried ()
  "A live, un-displayed buffer is shown via `display-buffer' by default."
  (let ((pearl-surface-buffer t) (pearl-surface-select-window nil) (shown nil))
    (cl-letf (((symbol-function 'get-buffer-window) (lambda (&rest _) nil))
              ((symbol-function 'display-buffer) (lambda (b &rest _) (setq shown b)))
              ((symbol-function 'pop-to-buffer) (lambda (&rest _) (setq shown 'pop))))
      (with-temp-buffer
        (pearl--surface-buffer (current-buffer))
        (should (eq shown (current-buffer)))))))

(ert-deftest test-pearl-surface-buffer-skips-when-already-shown ()
  "A buffer already visible in some window is left alone."
  (let ((pearl-surface-buffer t) (shown nil))
    (cl-letf (((symbol-function 'get-buffer-window) (lambda (&rest _) 'a-window))
              ((symbol-function 'display-buffer) (lambda (&rest _) (setq shown t)))
              ((symbol-function 'pop-to-buffer) (lambda (&rest _) (setq shown t))))
      (with-temp-buffer
        (pearl--surface-buffer (current-buffer))
        (should-not shown)))))

(ert-deftest test-pearl-surface-buffer-select-window-uses-pop-to-buffer ()
  "With `pearl-surface-select-window' non-nil, focus follows via `pop-to-buffer'."
  (let ((pearl-surface-buffer t) (pearl-surface-select-window t) (how nil))
    (cl-letf (((symbol-function 'get-buffer-window) (lambda (&rest _) nil))
              ((symbol-function 'display-buffer) (lambda (&rest _) (setq how 'display)))
              ((symbol-function 'pop-to-buffer) (lambda (&rest _) (setq how 'pop))))
      (with-temp-buffer
        (pearl--surface-buffer (current-buffer))
        (should (eq how 'pop))))))

(ert-deftest test-pearl-surface-buffer-dead-buffer-is-noop ()
  "A killed buffer is never surfaced."
  (let ((pearl-surface-buffer t) (shown nil) (buf (generate-new-buffer "x")))
    (kill-buffer buf)
    (cl-letf (((symbol-function 'display-buffer) (lambda (&rest _) (setq shown t)))
              ((symbol-function 'pop-to-buffer) (lambda (&rest _) (setq shown t))))
      (pearl--surface-buffer buf)
      (should-not shown))))

(provide 'test-pearl-surface)
;;; test-pearl-surface.el ends here