;;; org-drill-config.el --- Org Drill Settings -*- lexical-binding: t; coding: utf-8; -*-
;; author: Craig Jennings <c@cjennings.net>
;;; Commentary:
;;
;; Layer: 4 (Optional).
;; Category: O/D/P.
;; Load shape: eager.
;; Eager reason: none; optional flashcard workflow, a command-loaded deferral
;;   candidate for Phase 4.
;; Top-level side effects: defines a drill keymap, registers it under cj/custom-keymap.
;; Runtime requires: user-constants, keybindings.
;; Direct test load: yes (requires keybindings explicitly).
;;
;; Notes: Org-Drill
;; `C-; D s' picks a flashcard file from `drill-dir' and starts a session;
;; `C-u C-; D s' lets you pick the directory first.  `C-; D f' drills
;; whatever Org file is current, so any drill file anywhere works.

;; Capture templates:
;; - "d" for web/EPUB drill captures (uses %i for selected text, %:link for source)
;; - "f" for PDF drill captures (uses special PDF region extraction)

;; The javascript bookmarklet for capturing from web to org-drill:
;; javascript:location.href='org-protocol://capture?template=d&url=%27+encodeURIComponent(location.href)+%27&title=%27+encodeURIComponent(document.title)+%27&body=%27+encodeURIComponent(window.getSelection());void(0);

;; Create a bookmark, add "Drill Entry" to the name field and the above snippet to the URL field.

;;; Code:

(require 'user-constants)                       ;; `drill-dir'
(require 'keybindings)                           ;; provides `cj/custom-keymap'
(declare-function org-drill "org-drill" (&optional scope drill-match resume-p))
(declare-function org-drill-resume "org-drill" ())
(declare-function org-capture "org-capture" (&optional goto keys))
(declare-function org-refile "org-refile" (&optional arg1 default-buffer rfloc msg))
(defvar org-refile-targets)                     ;; org-refile.el

;; ------------------------------ Drill Commands -------------------------------

(defun cj/--drill-files-in (dir)
  "Return the drill Org file names directly inside DIR (no leading dots)."
  (directory-files dir nil "^[^.].*\\.org$"))

(defun cj/--drill-files-or-error (dir)
  "Return the drill Org files in DIR, or signal a clear `user-error'.
Errors when DIR is missing, unreadable, or has no drill files, so callers
fail with an actionable message instead of a low-level `directory-files'
error or an empty `completing-read'.  This is the single entry point the
drill commands and the drill capture templates share."
  (unless (and (file-directory-p dir) (file-readable-p dir))
    (user-error "Drill directory missing or unreadable: %s" dir))
  (let ((files (cj/--drill-files-in dir)))
    (unless files
      (user-error "No drill files (.org) found in %s" dir))
    files))

(defun cj/--drill-pick-file (dir)
  "Prompt for one of the drill Org files in DIR; return its absolute path."
  (expand-file-name
   (completing-read "Choose flashcard file: " (cj/--drill-files-or-error dir) nil t)
   dir))

(defun cj/--drill-pick-dir (other-dir)
  "Return the directory to pick drill files from.
With OTHER-DIR non-nil, prompt for one; otherwise use `drill-dir'."
  (if other-dir (read-directory-name "Drill files in: ") drill-dir))

(defun cj/drill-start (&optional other-dir)
  "Pick a drill Org file and start an `org-drill' session.
With a prefix arg OTHER-DIR, prompt for the directory to choose from
instead of the default `drill-dir'."
  (interactive "P")
  (find-file (cj/--drill-pick-file (cj/--drill-pick-dir other-dir)))
  (org-drill))

(defun cj/drill-this-file ()
  "Start an `org-drill' session on the current Org buffer.
Use this to drill any drill file you have open, wherever it lives."
  (interactive)
  (unless (derived-mode-p 'org-mode)
    (user-error "Not an Org buffer -- visit a `.org' file first"))
  (org-drill))

(defun cj/drill-edit (&optional other-dir)
  "Pick a drill Org file and open it for editing.
With a prefix arg OTHER-DIR, prompt for the directory instead of `drill-dir'."
  (interactive "P")
  (find-file (cj/--drill-pick-file (cj/--drill-pick-dir other-dir))))

(defun cj/drill-capture ()
  "Quickly capture a drill question."
  (interactive)
  (org-capture nil "d"))

(defun cj/drill-refile ()
  "Refile to a drill file."
  (interactive)
  (setq org-refile-targets '((nil :maxlevel . 1)
                             (drill-dir :maxlevel . 1)))
  (call-interactively 'org-refile))

;; ------------------------------- Drill Keymap --------------------------------

(defvar-keymap cj/drill-map
  :doc "Keymap for org-drill"
  "s" #'cj/drill-start
  "f" #'cj/drill-this-file
  "e" #'cj/drill-edit
  "c" #'cj/drill-capture
  "r" #'cj/drill-refile
  "R" #'org-drill-resume)

(cj/register-prefix-map "D" cj/drill-map)

(with-eval-after-load 'which-key
  (which-key-add-key-based-replacements
    "C-; D" "org-drill menu"
    "C-; D s" "start drill (C-u: pick dir)"
    "C-; D f" "drill current file"
    "C-; D e" "edit drill file (C-u: pick dir)"
    "C-; D c" "capture question"
    "C-; D r" "refile to drill"
    "C-; D R" "resume drill"))

;; --------------------------------- Org Drill ---------------------------------

(use-package org-drill
  ;; :vc (:url "git@cjennings.net:org-drill.git"
  ;;      :branch "main"
  ;;      :rev :newest)
  :load-path "~/code/org-drill"  ;; local dev checkout — switch back to :vc above when done
  :after (org org-capture)
  :demand t
  :commands (org-drill org-drill-resume)
  :custom
  (org-drill-leech-failure-threshold 50 "leech cards = 50 wrong answers")
  (org-drill-leech-method 'warn "leech cards show warnings")
  (org-drill-use-visible-cloze-face-p t "cloze text shows up in a different font")
  (org-drill-hide-item-headings-p t "don't show heading text")
  (org-drill-maximum-items-per-session 100 "drill sessions end after 100 cards")
  (org-drill-maximum-duration 30 "each drill session can last up to 30 mins")
  (org-drill-add-random-noise-to-intervals-p t "vary the days to repetition slightly")
  (org-drill-text-size-during-session 24 "24-point font for comfortable reading")
  (org-drill-use-variable-pitch t "variable-pitch font for readability")
  (org-drill-hide-modeline-during-session t "hide the modeline for a cleaner display"))

(provide 'org-drill-config)
;;; org-drill-config.el ends here.