;;; fix-dirvish-preview.el --- fix dirvish preview on windows  -*- lexical-binding: t -*-

;;; Commentary:
;; Fix video-mtn preview issue on Windows
;; The problem: mtn generates thumbnails with filename like "video.mp4.jpg",
;; but dirvish expects MD5-based filename like "a1b2c3d4.jpg"

;;; Code:

(with-eval-after-load 'dirvish
  ;; Function to find mtn output file for a given video file in cache directory
  (defun my/dirvish-find-mtn-output (video-file cache-dir ext)
    "Find mtn-generated thumbnail for VIDEO-FILE in CACHE-DIR with extension EXT."
    (let* ((file-base (file-name-base video-file))
           ;; mtn generates: [filename].[ext].jpg
           (mtn-pattern (format "%s.%s.jpg" (regexp-quote file-base) ext))
           (files (directory-files cache-dir t mtn-pattern)))
      (car files)))

  ;; Advice to fix the sentinel after mtn generates the thumbnail
  (defun my/dirvish-media--cache-sentinel-advice (orig-fun proc exit-code)
    "Advice to rename mtn output to MD5 format after generation."
    (let* ((video-path (process-get proc 'path))
           (ext (downcase (or (file-name-extension video-path) "")))
           (dv (dirvish-curr)))
      (when (and (memq system-type '(ms-dos windows-nt))
                 (member ext dirvish-video-exts)
                 dv)
        ;; Try to find and rename mtn output to MD5 format
        (let* ((width (dirvish-media--img-size (dv-preview-window dv)))
               (cache (dirvish--img-thumb-name video-path width ".jpg"))
               (cache-dir (dirvish--get-parent-path cache))
               (mtn-file (my/dirvish-find-mtn-output video-path cache-dir ext)))
          (when (and mtn-file (file-exists-p mtn-file) (not (file-exists-p cache)))
            (rename-file mtn-file cache)))))
    ;; Call original function
    (funcall orig-fun proc exit-code))

  ;; Apply advice
  (advice-add 'dirvish-media--cache-sentinel :around #'my/dirvish-media--cache-sentinel-advice))

(provide 'fix-dirvish-preview)

;;; fix-dirvish-preview.el ends here