;;; test-pearl-sort.el --- Tests for interactive sort/order -*- 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 changing the order of the active view interactively:
;; the source-plist helpers (symbol :sort/:order for filters,
;; :client-sort/:client-order for views), the #+LINEAR-SOURCE header
;; rewrite, the byte-for-byte client-side subtree reorder (preserving
;; local edits), and the pearl--apply-sort routing (client vs server vs
;; refuse) plus the toggle target.

;;; Code:

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

(defmacro test-pearl-sort--in-org (content &rest body)
  "Run BODY in an org-mode temp buffer holding CONTENT."
  (declare (indent 1))
  `(let ((org-todo-keywords '((sequence "TODO" "IN-PROGRESS" "|" "DONE"))))
     (with-temp-buffer
       (insert ,content)
       (org-mode)
       (goto-char (point-min))
       ,@body)))

(defconst test-pearl-sort--flat
  (concat
   "#+title: Linear — My open issues\n"
   "#+STARTUP: show2levels\n"
   "#+TODO: TODO | DONE\n"
   "#+LINEAR-SOURCE: (:type filter :name \"My open issues\" :filter (:open t))\n"
   "#+LINEAR-COUNT: 2\n\n"
   "* My open issues\n"
   "** TODO [#C] SE-2: Beta\n:PROPERTIES:\n:LINEAR-ID: i2\n:LINEAR-IDENTIFIER: SE-2\n:END:\n"
   "Body beta.\n"
   "** TODO [#A] SE-1: Alpha\n:PROPERTIES:\n:LINEAR-ID: i1\n:LINEAR-IDENTIFIER: SE-1\n:END:\n"
   "Body alpha.\n")
  "A flat two-issue buffer: SE-2 [#C] Beta first, SE-1 [#A] Alpha second.")

(defun test-pearl-sort--issue-ids ()
  "Return the LINEAR-IDs of the level-2 issue headings in document order."
  (let (ids)
    (save-excursion
      (goto-char (point-min))
      (while (re-search-forward "^\\*\\* " nil t)
        (let ((id (org-entry-get nil "LINEAR-ID")))
          (when id (push id ids)))))
    (nreverse ids)))

;;; source-plist helpers

(ert-deftest test-pearl-source-with-sort-filter-uses-sort-keys ()
  "A filter source records the interactive sort under :sort/:order (symbols)."
  (let ((out (pearl--source-with-sort '(:type filter :name "x") 'priority 'asc)))
    (should (eq (plist-get out :sort) 'priority))
    (should (eq (plist-get out :order) 'asc))))

(ert-deftest test-pearl-source-with-sort-view-uses-client-keys ()
  "A view source records the interactive sort under :client-sort/:client-order,
leaving its server :sort (an IssueSortInput) untouched."
  (let ((out (pearl--source-with-sort
              '(:type view :name "v" :id "vid" :sort ((:priority "Ascending")))
              'title 'desc)))
    (should (eq (plist-get out :client-sort) 'title))
    (should (eq (plist-get out :client-order) 'desc))
    (should (equal (plist-get out :sort) '((:priority "Ascending"))))))

(ert-deftest test-pearl-effective-sort-order-filter ()
  "Effective client sort for a filter is its :sort/:order."
  (should (equal (pearl--effective-sort-order '(:type filter :sort priority :order asc))
                 '(priority . asc))))

(ert-deftest test-pearl-effective-sort-order-view-with-client ()
  "Effective client sort for a view is its :client-sort/:client-order."
  (should (equal (pearl--effective-sort-order
                  '(:type view :sort ((:x "y")) :client-sort title :client-order desc))
                 '(title . desc))))

(ert-deftest test-pearl-effective-sort-order-view-without-client ()
  "A view with no client sort has no effective client sort (server order honored)."
  (should (equal (pearl--effective-sort-order '(:type view :sort ((:x "y"))))
                 '(nil . nil))))

;;; symbol contract

(ert-deftest test-pearl-check-sort-order-valid ()
  "Valid sort/order symbols pass."
  (should (pearl--check-sort-order 'priority 'asc))
  (should (pearl--check-sort-order 'updated 'desc))
  (should (pearl--check-sort-order nil nil)))

(ert-deftest test-pearl-check-sort-order-unknown-sort-errors ()
  "An unknown sort symbol signals a user-error."
  (should-error (pearl--check-sort-order 'sideways 'asc) :type 'user-error))

(ert-deftest test-pearl-check-sort-order-unknown-order-errors ()
  "An unknown order symbol signals a user-error."
  (should-error (pearl--check-sort-order 'priority 'upward) :type 'user-error))

;;; header rewrite

(ert-deftest test-pearl-write-linear-source-header-roundtrips ()
  "Writing a new source header is read back by `pearl--read-active-source'."
  (test-pearl-sort--in-org test-pearl-sort--flat
    (pearl--write-linear-source-header
     '(:type filter :name "My open issues" :filter (:open t)
       :sort priority :order asc))
    (let ((src (pearl--read-active-source)))
      (should (eq (plist-get src :sort) 'priority))
      (should (eq (plist-get src :order) 'asc)))))

(ert-deftest test-pearl-write-source-header-survives-print-length ()
  "A long source serializes in full even when print-length/level are bound low.
A view source is long enough to truncate under a user's `print-length', which
would persist an unreadable #+LINEAR-SOURCE and break refresh/sort."
  (test-pearl-sort--in-org test-pearl-sort--flat
    (let ((print-length 2) (print-level 2)
          (src '(:type view :name "V" :id "vid" :url "u" :sort ((:a 1))
                 :show-completed "none" :group "x"
                 :client-sort priority :client-order asc)))
      (pearl--write-linear-source-header src)
      (should (equal (pearl--read-active-source) src)))))

;;; client-side reorder

(ert-deftest test-pearl-reorder-priority-ascending ()
  "Priority-ascending reorder puts the [#A] issue before the [#C] issue."
  (test-pearl-sort--in-org test-pearl-sort--flat
    (should (eq (pearl--reorder-issue-subtrees 'priority 'asc) t))
    (should (equal (test-pearl-sort--issue-ids) '("i1" "i2")))))

(ert-deftest test-pearl-reorder-priority-descending ()
  "Priority-descending reorder keeps the [#C] issue before the [#A] issue."
  (test-pearl-sort--in-org test-pearl-sort--flat
    (should (eq (pearl--reorder-issue-subtrees 'priority 'desc) t))
    (should (equal (test-pearl-sort--issue-ids) '("i2" "i1")))))

(ert-deftest test-pearl-reorder-title-ascending ()
  "Title-ascending reorder sorts Alpha before Beta."
  (test-pearl-sort--in-org test-pearl-sort--flat
    (should (eq (pearl--reorder-issue-subtrees 'title 'asc) t))
    (should (equal (test-pearl-sort--issue-ids) '("i1" "i2")))))

(ert-deftest test-pearl-reorder-preserves-local-edits ()
  "Reorder moves whole subtrees byte-for-byte, keeping an unsaved body edit."
  (test-pearl-sort--in-org test-pearl-sort--flat
    ;; Edit SE-1's body in place before sorting.
    (goto-char (point-min))
    (search-forward "Body alpha.")
    (replace-match "Body alpha EDITED LOCALLY.")
    (should (eq (pearl--reorder-issue-subtrees 'priority 'asc) t))
    (should (equal (test-pearl-sort--issue-ids) '("i1" "i2")))
    (goto-char (point-min))
    (should (search-forward "Body alpha EDITED LOCALLY." nil t))))

(ert-deftest test-pearl-reorder-grouped-refuses ()
  "A grouped buffer (issues below level 2) refuses with 'grouped, unchanged."
  (test-pearl-sort--in-org
      (concat
       "#+LINEAR-SOURCE: (:type view :name \"v\" :id \"vid\")\n\n"
       "* v\n"
       "** Group One\n"
       "*** TODO [#C] SE-2: Beta\n:PROPERTIES:\n:LINEAR-ID: i2\n:END:\n"
       "*** TODO [#A] SE-1: Alpha\n:PROPERTIES:\n:LINEAR-ID: i1\n:END:\n")
    (let ((before (buffer-string)))
      (should (eq (pearl--reorder-issue-subtrees 'priority 'asc) 'grouped))
      (should (equal (buffer-string) before)))))

(ert-deftest test-pearl-reorder-no-issues ()
  "A buffer with no issue headings returns 'no-issues."
  (test-pearl-sort--in-org "* Nothing here\nplain text\n"
    (should (eq (pearl--reorder-issue-subtrees 'priority 'asc) 'no-issues))))

(ert-deftest test-pearl-reorder-keeps-non-issue-subtree-last ()
  "A level-2 heading with no LINEAR-ID is kept (sorted last), not dropped."
  (test-pearl-sort--in-org
      (concat
       "#+LINEAR-SOURCE: (:type filter :name \"x\" :filter nil)\n\n"
       "* x\n"
       "** TODO [#C] SE-2: Beta\n:PROPERTIES:\n:LINEAR-ID: i2\n:LINEAR-IDENTIFIER: SE-2\n:END:\n"
       "** A stray local heading\nsome notes\n"
       "** TODO [#A] SE-1: Alpha\n:PROPERTIES:\n:LINEAR-ID: i1\n:LINEAR-IDENTIFIER: SE-1\n:END:\n")
    (should (eq (pearl--reorder-issue-subtrees 'priority 'asc) t))
    (should (equal (test-pearl-sort--issue-ids) '("i1" "i2")))
    (goto-char (point-min))
    (should (search-forward "A stray local heading" nil t))))

(ert-deftest test-pearl-reorder-by-id-ranks ()
  "With an id-rank hash, subtrees are laid out in the ranked order (server sort)."
  (test-pearl-sort--in-org test-pearl-sort--flat
    (let ((ranks (make-hash-table :test 'equal)))
      ;; Rank i1 before i2, the reverse of the buffer's i2,i1 order.
      (puthash "i1" 0 ranks)
      (puthash "i2" 1 ranks)
      (should (eq (pearl--reorder-issue-subtrees nil 'asc ranks) t))
      (should (equal (test-pearl-sort--issue-ids) '("i1" "i2"))))))

;;; toggle target

(ert-deftest test-pearl-toggle-target-filter-no-sort-defaults ()
  "Toggle on a filter with no sort establishes updated/desc."
  (should (equal (pearl--toggle-sort-target '(:type filter))
                 '(updated . desc))))

(ert-deftest test-pearl-toggle-target-filter-flips-order ()
  "Toggle on a filter flips the current order, keeping the sort."
  (should (equal (pearl--toggle-sort-target '(:type filter :sort priority :order asc))
                 '(priority . desc))))

(ert-deftest test-pearl-toggle-target-view-needs-client-sort ()
  "Toggle on a view with no client sort refuses (nothing to flip)."
  (should-error (pearl--toggle-sort-target '(:type view :sort ((:x "y"))))
                :type 'user-error))

(ert-deftest test-pearl-toggle-target-view-flips-client-order ()
  "Toggle on a view flips the client order."
  (should (equal (pearl--toggle-sort-target
                  '(:type view :client-sort title :client-order desc))
                 '(title . asc))))

;;; apply-sort routing

(ert-deftest test-pearl-apply-sort-view-server-key-refuses ()
  "A created/updated sort on a view is refused (Linear has no view orderBy)."
  (test-pearl-sort--in-org test-pearl-sort--flat
    (should-error (pearl--apply-sort '(:type view :name "v" :id "vid") 'updated 'desc)
                  :type 'user-error)))

(ert-deftest test-pearl-apply-sort-filter-client-key-reorders-and-persists ()
  "A priority sort on a filter reorders in place and writes :sort to the header."
  (test-pearl-sort--in-org test-pearl-sort--flat
    (should (eq (pearl--apply-sort
                 '(:type filter :name "My open issues" :filter (:open t))
                 'priority 'asc)
                'client))
    (should (equal (test-pearl-sort--issue-ids) '("i1" "i2")))
    (should (eq (plist-get (pearl--read-active-source) :sort) 'priority))))

(ert-deftest test-pearl-apply-sort-view-client-key-persists-client-keys ()
  "A priority sort on a view reorders and writes :client-sort, not :sort."
  (test-pearl-sort--in-org
      (concat
       "#+LINEAR-SOURCE: (:type view :name \"v\" :id \"vid\" :sort ((:priority \"Ascending\")))\n\n"
       "* v\n"
       "** TODO [#C] SE-2: Beta\n:PROPERTIES:\n:LINEAR-ID: i2\n:LINEAR-IDENTIFIER: SE-2\n:END:\n"
       "** TODO [#A] SE-1: Alpha\n:PROPERTIES:\n:LINEAR-ID: i1\n:LINEAR-IDENTIFIER: SE-1\n:END:\n")
    (should (eq (pearl--apply-sort
                 (pearl--read-active-source) 'priority 'asc)
                'client))
    (should (equal (test-pearl-sort--issue-ids) '("i1" "i2")))
    (let ((src (pearl--read-active-source)))
      (should (eq (plist-get src :client-sort) 'priority))
      (should (equal (plist-get src :sort) '((:priority "Ascending")))))))

(ert-deftest test-pearl-apply-sort-grouped-refuses-no-header-write ()
  "A grouped buffer refuses the client reorder and leaves the header unchanged."
  (test-pearl-sort--in-org
      (concat
       "#+LINEAR-SOURCE: (:type filter :name \"x\" :filter nil)\n\n"
       "* x\n"
       "** Group\n"
       "*** TODO [#A] SE-1: Alpha\n:PROPERTIES:\n:LINEAR-ID: i1\n:END:\n")
    (should (eq (pearl--apply-sort '(:type filter :name "x" :filter nil) 'priority 'asc)
                'grouped))
    (should (null (plist-get (pearl--read-active-source) :sort)))))

;;; server-side refetch persistence (HP3)

(ert-deftest test-pearl-apply-server-sort-ok-writes-header ()
  "A successful server refetch writes the updated sort into #+LINEAR-SOURCE."
  (test-pearl-sort--in-org test-pearl-sort--flat
    (cl-letf (((symbol-function 'pearl--query-issues-async)
               (lambda (_filter callback &optional _order-by)
                 (funcall callback '(:status ok :issues nil :truncated nil))))
              ((symbol-function 'pearl--merge-query-result) (lambda (&rest _) nil))
              ((symbol-function 'pearl--progress) (lambda (&rest _) nil)))
      (pearl--apply-server-sort
       '(:type filter :name "My open issues" :filter (:open t) :sort updated :order asc)
       'updated 'asc)
      (let ((src (pearl--read-active-source)))
        (should (eq (plist-get src :sort) 'updated))
        (should (eq (plist-get src :order) 'asc))))))

(ert-deftest test-pearl-apply-server-sort-failure-keeps-header ()
  "A failed server refetch leaves the #+LINEAR-SOURCE header unchanged (HP3)."
  (test-pearl-sort--in-org test-pearl-sort--flat
    (cl-letf (((symbol-function 'pearl--query-issues-async)
               (lambda (_filter callback &optional _order-by)
                 (funcall callback '(:status error :message "boom"))))
              ((symbol-function 'pearl--merge-query-result) (lambda (&rest _) nil))
              ((symbol-function 'pearl--progress) (lambda (&rest _) nil)))
      (pearl--apply-server-sort
       '(:type filter :name "My open issues" :filter (:open t) :sort updated :order asc)
       'updated 'asc)
      (should (null (plist-get (pearl--read-active-source) :sort))))))

;;; fold restoration after a reorder

;; The reorder rewrites the issue block with delete+insert, which drops the
;; fold/visibility overlays so every subtree comes back expanded.  Both sort
;; paths must re-fold afterward (pearl--restore-page-visibility) so the page
;; stays the scannable, folded outline it was before the sort.  A refusal
;; (grouped buffer, failed refetch) moves nothing and must not re-fold.

(ert-deftest test-pearl-apply-sort-client-restores-fold ()
  "A successful client reorder re-folds the page."
  (test-pearl-sort--in-org test-pearl-sort--flat
    (let (restored)
      (cl-letf (((symbol-function 'pearl--restore-page-visibility)
                 (lambda () (setq restored t))))
        (should (eq (pearl--apply-sort
                     '(:type filter :name "My open issues" :filter (:open t))
                     'priority 'asc)
                    'client))
        (should restored)))))

(ert-deftest test-pearl-apply-sort-grouped-skips-fold-restore ()
  "A grouped refusal moves nothing, so it does not re-fold."
  (test-pearl-sort--in-org
      (concat
       "#+LINEAR-SOURCE: (:type filter :name \"x\" :filter nil)\n\n"
       "* x\n"
       "** Group\n"
       "*** TODO [#A] SE-1: Alpha\n:PROPERTIES:\n:LINEAR-ID: i1\n:END:\n")
    (let (restored)
      (cl-letf (((symbol-function 'pearl--restore-page-visibility)
                 (lambda () (setq restored t))))
        (pearl--apply-sort '(:type filter :name "x" :filter nil) 'priority 'asc)
        (should-not restored)))))

(ert-deftest test-pearl-apply-server-sort-ok-restores-fold ()
  "A successful server refetch re-folds the reordered page."
  (test-pearl-sort--in-org test-pearl-sort--flat
    (let (restored)
      (cl-letf (((symbol-function 'pearl--query-issues-async)
                 (lambda (_filter callback &optional _order-by)
                   (funcall callback '(:status ok :issues nil :truncated nil))))
                ((symbol-function 'pearl--merge-query-result) (lambda (&rest _) nil))
                ((symbol-function 'pearl--progress) (lambda (&rest _) nil))
                ((symbol-function 'pearl--restore-page-visibility)
                 (lambda () (setq restored t))))
        (pearl--apply-server-sort
         '(:type filter :name "My open issues" :filter (:open t) :sort updated :order asc)
         'updated 'asc)
        (should restored)))))

(ert-deftest test-pearl-apply-server-sort-failure-skips-fold-restore ()
  "A failed server refetch moves nothing, so it does not re-fold."
  (test-pearl-sort--in-org test-pearl-sort--flat
    (let (restored)
      (cl-letf (((symbol-function 'pearl--query-issues-async)
                 (lambda (_filter callback &optional _order-by)
                   (funcall callback '(:status error :message "boom"))))
                ((symbol-function 'pearl--merge-query-result) (lambda (&rest _) nil))
                ((symbol-function 'pearl--progress) (lambda (&rest _) nil))
                ((symbol-function 'pearl--restore-page-visibility)
                 (lambda () (setq restored t))))
        (pearl--apply-server-sort
         '(:type filter :name "My open issues" :filter (:open t) :sort updated :order asc)
         'updated 'asc)
        (should-not restored)))))

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