;;; ss-core.el --- Shared core setup -*- lexical-binding: t; -*-

;;; Commentary:

;; Shared startup helpers, package bootstrap, paths, and editor defaults.

;;; Code:

(require 'subr-x)

(defconst ss-minimum-emacs-version "27.1"
  "Minimum supported Emacs version.")

(defconst ss-warning-emacs-version "28.1"
  "Version threshold for compatibility warnings.")

(defconst ss-spell-check-support-enabled nil)
(defconst ss-is-windows (memq system-type '(windows-nt ms-dos cygwin)))
(defconst ss-is-linux (eq system-type 'gnu/linux))
(defconst ss-is-mac (eq system-type 'darwin))

(defconst ss-org-directory (expand-file-name "~/org/")
  "Root directory for Org files.")

(defconst ss-journal-file (expand-file-name "journal.org" ss-org-directory)
  "Single-file work journal for operational capture.")

(defconst ss-org-projects-directory (expand-file-name "projects/" ss-org-directory)
  "Directory for project notes.")

(defconst ss-org-areas-directory (expand-file-name "areas/" ss-org-directory)
  "Directory for area notes.")

(defconst ss-org-resources-directory (expand-file-name "resources/" ss-org-directory)
  "Directory for resource notes.")

(defconst ss-org-archives-directory (expand-file-name "archives/" ss-org-directory)
  "Directory for archived notes.")

(defconst ss-moc-file (expand-file-name "moc.org" ss-org-directory)
  "Central MOC note.")

(defconst ss-crm-file (expand-file-name "areas/people/people.org" ss-org-directory)
  "Single source of truth for the people CRM.")

(defconst ss-journal-section-headings
  '("Tasks" "Notes" "Meetings")
  "Per-day section headings maintained under each journal datetree entry.")

(defconst ss-org-agenda-directories
  (list ss-org-projects-directory
        ss-org-areas-directory
        ss-org-resources-directory)
  "Directories whose Org files feed the agenda.")

(defun ss-feature-enabled-p (feature)
  "Return non-nil when FEATURE is enabled in `ss-enabled-features'."
  (memq feature ss-enabled-features))

(defun ss-require-existing-directory (directory)
  "Return DIRECTORY, signaling when it does not exist."
  (unless (file-directory-p directory)
    (user-error "Directory does not exist: %s" directory))
  directory)

(defun ss-require-existing-file (file)
  "Return FILE, signaling when it does not exist."
  (unless (file-exists-p file)
    (user-error "File does not exist: %s" file))
  file)

(defun ss-enable-prose-abbrev-mode ()
  "Enable abbrev mode in prose buffers.
We keep this mode-local so code buffers stay on their own completion rules."
  (abbrev-mode 1))

(defun ss-core-setup ()
  "Initialize shared core behavior."
  (let ((minver ss-minimum-emacs-version))
    (when (version< emacs-version minver)
      (error "Your Emacs is too old -- this config requires v%s or higher" minver)))
  (when (version< emacs-version ss-warning-emacs-version)
    (message
     (concat
      "Your Emacs is old, and some functionality in this config will be "
      "disabled. Please upgrade if possible.")))

  ;; Keep custom-set-variables out of the main config.
  (setq custom-file (expand-file-name "custom.el" user-emacs-directory))

  (require 'package)
  (setq package-archives
        (append '(("melpa" . "https://melpa.org/packages/"))
                package-archives)
        package-archive-priorities '(("gnu" . 10)
                                     ("nongnu" . 8)
                                     ("melpa" . 5))
        package-install-upgrade-built-in t
        use-package-always-ensure nil)
  (package-initialize)
  (require 'use-package)
  (require 'abbrev)

  (set-language-environment "UTF-8")
  (set-default-coding-systems 'utf-8)
  (prefer-coding-system 'utf-8)

  (setq abbrev-file-name (expand-file-name "abbrev_defs" user-emacs-directory)
        save-abbrevs 'silently)
  (when (file-exists-p abbrev-file-name)
    (quietly-read-abbrev-file abbrev-file-name))

  (dolist (hook '(text-mode-hook org-mode-hook))
    (add-hook hook #'ss-enable-prose-abbrev-mode))

  (setq auto-save-default nil
        backup-inhibited t
        echo-keystrokes 0.1
        compilation-ask-about-save nil
        mouse-wheel-scroll-amount '(1 ((shift) . 1))
        mouse-wheel-progressive-speed nil
        mouse-wheel-follow-mouse t
        scroll-step 1
        scroll-conservatively 101
        enable-recursive-minibuffers t
        gc-cons-threshold (* 128 1024 1024)
        read-process-output-max (* 4 1024 1024)
        process-adaptive-read-buffering nil)

  (fset 'yes-or-no-p 'y-or-n-p)
  (global-auto-revert-mode 1)
  (delete-selection-mode 1)

  (setq-default indent-tabs-mode nil
                fill-column 80
                tab-width 2
                indicate-empty-lines t
                sentence-end-double-space nil))

(defun ss-core-load-custom-file ()
  "Load `custom-file' when it exists."
  (when (file-exists-p custom-file)
    (load custom-file nil 'nomessage)))

(provide 'ss-core)

;;; ss-core.el ends here