;;; init.el --- Emacs configuration  -*- lexical-binding: t; -*-

(require 'package)
(add-to-list 'package-archives
             '("melpa" . "https://melpa.org/packages/") t)
(package-initialize)

(unless package-archive-contents
  (package-refresh-contents))

(require 'use-package)
(setq use-package-always-ensure t)

(scroll-bar-mode -1)
(setq display-line-numbers-type 'relative)
(global-display-line-numbers-mode 1)
(setq-default indent-tabs-mode nil)

;; Translucent background (text stays opaque).  Needs a pgtk build under a
;; compositing WM; provided via nixos-config's emacs-pgtk package.
;;(defvar my/frame-alpha 90
;;  "Background opacity percentage for Emacs frames (100 = opaque).")
;;(set-frame-parameter nil 'alpha-background my/frame-alpha)
;;(add-to-list 'default-frame-alist `(alpha-background . ,my/frame-alpha))
;;(defun my/toggle-transparency ()
;;  "Toggle the selected frame between translucent and fully opaque."
;;  (interactive)
;;  (set-frame-parameter
;;   nil 'alpha-background
;;   (if (eql (frame-parameter nil 'alpha-background) 100) my/frame-alpha 100)))
;;(global-set-key (kbd "C-c t") #'my/toggle-transparency)

(setq custom-file
      (make-temp-file "emacs-custom-"))

;; move temp files out of the cwd
(let ((auto-save-dir (concat user-emacs-directory "auto-save/"))
      (backup-dir (concat user-emacs-directory "backups/")))
  (make-directory auto-save-dir t)
  (make-directory backup-dir t)
  (setq auto-save-file-name-transforms
        `((".*" ,auto-save-dir t)))
  (setq backup-directory-alist
        `(("." . ,backup-dir))))

(use-package evil
  :init
  (setq evil-want-keybinding nil)
  (setq evil-want-C-u-scroll t)
  :config
  (evil-mode 1))

(use-package evil-collection
  :after evil
  :config
  (evil-collection-init))

(add-hook 'eshell-mode-hook (lambda () (evil-insert-state)))

(use-package vs-dark-theme
  :config
  (load-theme 'vs-dark t))

(use-package apheleia
  :config
  (add-to-list 'apheleia-mode-alist '(scheme-mode . lisp-indent))
  (apheleia-global-mode +1))

(use-package geiser-guile)

(use-package markdown-mode
  :ensure t
  :mode ("\\.md\\'" . gfm-mode)
  :hook (markdown-mode . flyspell-mode))

(use-package nix-ts-mode
  :mode "\\.nix\\'")

(use-package rainbow-delimiters
  :hook (scheme-mode . rainbow-delimiters-mode))

(add-hook 'scheme-mode-hook #'electric-pair-local-mode)

(setq ispell-program-name "aspell"
      ispell-dictionary "en_US")
(add-hook 'markdown-mode-hook #'flyspell-mode)

(use-package magit
  :bind ("C-x g" . magit-status))

(use-package agent-shell
  ;; Talks to LLM coding agents over the Agent Client Protocol (ACP).
  ;; Pi needs the external `pi-acp` adapter on PATH (provided via nixos-config).
  ;; Pi authenticates via OAuth -- run `/login` inside the shell once; no API key.
  :bind ("C-c a p" . agent-shell-pi-start-agent)
  :config
  (setq agent-shell-pi-acp-command '("pi-acp"))
  ;; Start ready to type instead of in evil normal state.
  (add-hook 'agent-shell-mode-hook #'evil-insert-state)
  ;; Same GUI-Enter gotcha as mpdel: shell-maker binds submit via a
  ;; comint-send-input remap on RET/C-m, but a GUI frame's Enter sends
  ;; <return> -- which evil-collection shadows -- so input never gets sent.
  ;; Point <return> (and keypad Enter) straight at submit in insert state.
  (defun my/agent-shell-restore-ret ()
    (evil-local-set-key 'insert (kbd "<return>") #'shell-maker-submit)
    (evil-local-set-key 'insert (kbd "<kp-enter>") #'shell-maker-submit))
  (add-hook 'agent-shell-mode-hook #'my/agent-shell-restore-ret))

(use-package mpdel
  :after evil
  :config
  (mpdel-mode)
  ;; In a GUI frame the Enter key sends <return>, which evil-collection binds to
  ;; play/pause -- shadowing tablist's "descend into entry" command (that command
  ;; only sits on RET / C-m).  Point <return> (and the keypad Enter) at descend
  ;; in all mpdel list buffers (browser, playlists, ...).
  (defun my/mpdel-restore-ret ()
    (evil-local-set-key 'normal (kbd "<return>") #'tablist-find-entry)
    (evil-local-set-key 'normal (kbd "<kp-enter>") #'tablist-find-entry))
  (add-hook 'mpdel-tablist-mode-hook #'my/mpdel-restore-ret))

;; "Recently added" view.  MPD has no such entity, so subclass mpdel's filter
;; (which already renders a browsable, addable song list) and issue a search
;; sorted by modification time, newest first.
;;
;; This lives in its own top-level `with-eval-after-load' rather than in the
;; mpdel `:config' above: the `cl-defstruct' below `:include's libmpdel-filter,
;; which must exist when the struct is *macro-expanded*.  Emacs eager-expands
;; each top-level form before evaluating it, so inside :config the struct is
;; expanded before (mpdel-mode) has loaded libmpdel -- failing with
;; "libmpdel-filter is not a struct name".  By the time this separate form is
;; loaded, the use-package above has already pulled in mpdel/libmpdel.
(with-eval-after-load 'mpdel
  (require 'cl-lib)
  (require 'libmpdel)
  (defvar my/mpdel-recent-count 50
    "How many recently added songs `my/mpdel-recent' lists.")
  (cl-defstruct (my/mpdel-recent-entity (:include libmpdel-filter)))
  (cl-defmethod libmpdel-entity-name ((_e my/mpdel-recent-entity))
    "Recently added")
  (cl-defmethod libmpdel-list-songs ((_e my/mpdel-recent-entity) function)
    (libmpdel-send-command
     (format "search \"(file != \\\"\\\")\" sort -Last-Modified window 0:%d"
             my/mpdel-recent-count)
     (lambda (data)
       (funcall function (libmpdel--create-songs-from-data data)))))
  (defun my/mpdel-recent ()
    "Browse the most recently added songs, newest first."
    (interactive)
    (mpdel-core-open (make-my/mpdel-recent-entity :text "recently added")))
  (defun my/mpdel-recent-replace ()
    "Replace the current playlist with the recently added songs."
    (interactive)
    (libmpdel-list-songs
     (make-my/mpdel-recent-entity :text "recently added")
     (lambda (songs) (libmpdel-current-playlist-replace songs))))
  (global-set-key (kbd "C-c m r") #'my/mpdel-recent)
  (global-set-key (kbd "C-c m R") #'my/mpdel-recent-replace))