;;; my-ttrss.el -- ttrss utilities -*- lexical-binding: t -*-

;; Copyright (C) 2025  Free Software Foundation, Inc.

;; Author: Yuchen Pei <id@ypei.org>
;; Package-Requires: ((emacs "30.1"))

;; This file is part of dotted.

;; dotted is free software: you can redistribute it and/or modify it under
;; the terms of the GNU Affero General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; dotted 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 Affero General
;; Public License for more details.

;; You should have received a copy of the GNU Affero General Public
;; License along with dotted.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;; ttrss utilities.

;;; Code:

(require 'ttrss)

;;; TODO: my-ttrss-save-recent

(defun my-ttrss-hello ()
  (let ((sid (ttrss-login ttrss-address ttrss-user ttrss-password)))
    (message "Server running version %s and API level %d\n"
  		       (ttrss-get-version ttrss-address sid)
  		       (ttrss-get-api-level ttrss-address sid))
    (message "There are %s unread articles in %d feeds"
  		       (ttrss-get-unread ttrss-address sid)
  		       (length (ttrss-get-feeds ttrss-address sid :unread_only t)))))

(defun my-ttrss-fetch-feeds ()
  (let ((sid (ttrss-login ttrss-address ttrss-user ttrss-password)))
    (ttrss-get-feeds ttrss-address sid :cat_id -3)))

(defun my-ttrss-feed-dir (feed-title feed-id)
  (file-name-concat
   my-ttrss-dir
   (my-make-doc-file-name
    (format "%s [ttrss%s]" feed-title feed-id))))

(defun my-ttrss-feed-last-id-file (feed-info)
  (let* ((title (plist-get feed-info :title))
         (id (plist-get feed-info :id)))
    (expand-file-name
     (file-name-concat (my-ttrss-feed-dir title id) "last-id"))))

(defun my-ttrss-feed-get-last-id (feed-info)
  (let* ((file (my-ttrss-feed-last-id-file feed-info)))
    (if (file-exists-p file)
        (with-temp-buffer
          (insert-file-contents file)
          (string-to-number (buffer-string)))
      0)))

(defun my-ttrss-feed-write-last-id (feed-info last-id)
  (let* ((file (my-ttrss-feed-last-id-file feed-info))
         (inhibit-message t))
    (with-temp-buffer
      (insert (format "%d" last-id))
      (write-file file))))

(defun my-ttrss-fetch ()
  "Fetch and save latest articles from all feeds."
  (interactive)
  (let* ((sid (ttrss-login ttrss-address ttrss-user ttrss-password))
         (feeds (ttrss-get-feeds ttrss-address sid :cat_id -3))
         (n (length feeds)))
    (seq-do-indexed
     (lambda (feed i)
       (my-ttrss-fetch-feed-articles
        sid feed
        (format "[my-ttrss] (%d/%d) Fetching articles from %s..."
                (1+ i) n (plist-get feed :title))))
     feeds)))

(defun my-ttrss-fetch-feed-articles (sid feed &optional message-head)
  (unless message-head
    (setq message-head
          (format "[my-ttrss] Fetching articles from %s..."
                  (plist-get feed :title))))
  (message "%s" message-head)
  (let ((articles
         (ttrss-get-headlines
          ttrss-address sid
          :feed_id (plist-get feed :id) :show_content t :include_attachments t
          :since_id (my-ttrss-feed-last-id feed))))
    (seq-do 'my-ttrss-save-article articles)
    (unless (seq-empty-p articles)
      (my-ttrss-feed-write-last-id feed (plist-get (elt articles 0) :id)))
    (message
     "%s Done - total %d articles"
     message-head (length articles))))

(defun my-ttrss-fetch-latest-articles (n &optional since-id)
  "Fetch N latest articles."
  (let ((sid (ttrss-login ttrss-address ttrss-user ttrss-password)))
    (unless since-id (setq since-id 0))
    (if (ttrss-logged-in-p ttrss-address sid)
        (ttrss-get-headlines
         ttrss-address sid
         :feed_id -4 :limit n :show_content t :include_attachments t
         :since_id since-id)
      (message "Login failed"))))

(defun my-ttrss-save-article (info)
  (with-temp-buffer
    (insert "<!--\n Page saved with my-ttrss on "
            (current-time-string) "\n"
            (json-serialize (org-plist-delete info :content))
            "\n-->\n")
    (insert "<h2>" "<a href=\"" (plist-get info :link) "\">"
            (plist-get info :title) "</a>" "</h2>")
    (insert "<p>" "<a href=\"" (plist-get info :site_url) "\">"
            (plist-get info :feed_title) "</a>")
    (when-let ((author (plist-get info :author)))
      (unless (or (string-empty-p author)
                  (equal author (plist-get info :feed_title)))
        (insert " (" author ")")))
    (insert " "
            (format-time-string
             "%Y-%m-%d %a %H:%M:%S"
             (encode-time (decode-time (plist-get info :updated)))))
    (insert "</p>")
    (let ((tags (plist-get info :tags)))
      (unless (seq-empty-p tags)
        (insert "<p>tags: " (string-join tags ";") "</p>")))
    (insert (plist-get info :content))
    (let ((attached (plist-get info :attachments)))
      (unless (seq-empty-p attached)
        (insert "<p>Article attachments:</p>\n<ul>")
        (seq-do (lambda (at)
                  (let ((title (plist-get at :title))
                        (url (plist-get at :content_url)))
                    (insert "\n<li><a href=" url ">"
                            (if (string-empty-p title) url title)
                            "</a></li>")))
                attached)
        (insert "\n</ul>")))
    (let* ((change-major-mode-with-file-name nil)
           (coding-system-for-write 'utf-8)
           (inhibit-message t)
           (file-name (my-ttrss-format-file-name info))
           (dir (file-name-directory file-name)))
      (unless (file-exists-p dir) (make-directory dir t))
      (write-file file-name))))

(defvar my-ttrss-dir "~/Downloads")

(defun my-ttrss-format-file-name (info)
  "Format: $author - $title ($year) [ttrss$id].html"
  (let* ((author (plist-get info :author))
         (feed-title (plist-get info :feed_title))
         (feed-id (plist-get info :feed_id))
         (name
          (expand-file-name
           (file-name-concat
            (my-ttrss-feed-dir feed-title feed-id)
            (my-make-doc-file-name
             (format "%s - %s (%s) [ttrss%s].html"
                     (if (string-empty-p author)
                         feed-title
                       author)
                     (plist-get info :title)
                     (format-time-string
                      "%Y"
                      (encode-time (decode-time (plist-get info :updated))))
                     (plist-get info :id)))))))
    (if (length> name 250)
        (expand-file-name
         (file-name-concat
          (my-ttrss-feed-dir feed-title feed-id)
          (my-make-doc-file-name
           (format "_ - _ (%s) [ttrss%s].html"
                   (format-time-string
                    "%Y"
                    (encode-time (decode-time (plist-get info :updated))))
                   (plist-get info :id)))))
      name)))

(provide 'my-ttrss)
;;; my-ttrss.el ends here