1 files changed, 101 insertions, 0 deletions
diff --git a/.config/emacs/site-lisp/live-jq.el b/.config/emacs/site-lisp/live-jq.el
new file mode 100644
index 0000000..f8a0a7f
--- /dev/null
+++ b/.config/emacs/site-lisp/live-jq.el
@@ -0,0 +1,101 @@
+;; TODO: ‘defcustom’ this
+(defvar live-jq-major-mode
+  (cond ((fboundp #'json-ts-mode) #'json-ts-mode)
+        ((fboundp #'json-mode) #'json-mode))
+  "TODO")
+
+(defvar live-jq--input-buffer nil
+  "The buffer containing the original JSON data.")
+
+(defvar live-jq--preview-buffer "*JQ Preview*"
+  "The buffer showing the live jq results.")
+
+(defvar live-jq--last-query "")
+
+(defun live-jq--get-json-input ()
+  "Return the contents of the input buffer as a string."
+  (with-current-buffer live-jq--input-buffer
+    (buffer-substring-no-properties (point-min) (point-max))))
+
+(defun live-jq--run-jq (query)
+  "Run jq QUERY on the input buffer's content and return result string or nil on error."
+  (let ((json-input (live-jq--get-json-input)))
+    (with-temp-buffer
+      (insert json-input)
+      (let ((exit-code (call-process-region
+                        (point-min) (point-max)
+                        "jq" :delete t nil "--tab" query)))
+        (when (zerop exit-code)
+          (buffer-string))))))
+
+(defun live-jq--render-jq-preview (query)
+  "Update preview buffer with the result or error of jq QUERY."
+  (let* ((preview-buffer (get-buffer-create live-jq--preview-buffer))
+         (json-input (live-jq--get-json-input))
+         (inhibit-read-only t))
+    (with-current-buffer preview-buffer
+      (erase-buffer)
+      (condition-case err
+          (with-temp-buffer
+            (insert json-input)
+            (let ((exit-code (call-process-region
+                              (point-min) (point-max)
+                              "jq" nil preview-buffer nil "--tab" query)))
+              (when (not (zerop exit-code))
+                (erase-buffer)
+                (insert "%s\n%s"
+                        (propertize (format "jq error (exit %d): %s" exit-code query)
+                                    'face 'error)
+                        json-input))))
+        (error
+         (insert "%s\n%s"
+                 (propertize (format "Error: %s" err) 'face 'error)
+                 input-json)))
+      (goto-char (point-min))
+      (when live-jq-major-mode
+        (funcall live-jq-major-mode))))
+  (display-buffer live-jq--preview-buffer))
+
+(defun live-jq--minibuffer-update ()
+  "Update preview as user types."
+  (let ((query (minibuffer-contents)))
+    (unless (equal query live-jq--last-query)
+      (setq live-jq--last-query query)
+      (live-jq--render-jq-preview query))))
+
+;;;###autoload
+(defun live-jq ()
+  "Prompt for a jq query, show live results, and replace buffer on confirmation."
+  (interactive)
+  (unless (executable-find "jq")
+    (user-error "`jq' not found in PATH."))
+
+  (setq live-jq--input-buffer (current-buffer))
+  (setq live-jq--last-query "")
+
+  ;; Clean up preview buffer if user cancels with C-g
+  (let ((minibuffer-setup-hook
+         (list (lambda ()
+                 ;; Add post-command-hook for live preview
+                 (add-hook 'post-command-hook #'live-jq--minibuffer-update nil t)
+                 ;; Add abort cleanup
+                 (add-hook 'minibuffer-exit-hook
+                           (lambda ()
+                             (when (get-buffer live-jq--preview-buffer)
+                               (kill-buffer live-jq--preview-buffer)))
+                           nil t)))))
+    (let ((query (read-from-minibuffer (format-prompt "Query" nil))))
+      (unwind-protect
+          (let ((result (live-jq--run-jq query)))
+            (if result
+                (with-current-buffer live-jq--input-buffer
+                  (let ((inhibit-read-only t))
+                    (erase-buffer)
+                    (insert result))
+                  (message "jq applied."))
+              (user-error "Invalid jq query: see *jq-preview* for details")))
+        ;; Cleanup preview buffer after any outcome
+        (when (get-buffer live-jq--preview-buffer)
+          (kill-buffer live-jq--preview-buffer))))))
+
+(provide 'live-jq)