;;; init-completion.el --- Completion Configuration File -*- lexical-binding: t -*-
;;; Commentary:
;; Config for completion-at-point (corfu), as well as orderless (see also init-minibuffer.el)
;; Most of it is taken from the READMEs and wikis of those packages
;;; Code:

(use-package dabbrev
  :diminish
  :custom
  (setq dabbrev-case-distinction nil)
  (setq dabbrev-case-fold-search t)
  (setq dabbrev-case-replace nil))

(use-package hippie-expand
  :ensure nil
  :init
  (setq hippie-expand-try-functions-list
      '(;yas-hippie-try-expand
        try-expand-dabbrev
        try-expand-all-abbrevs
        try-expand-dabbrev-all-buffers
        try-expand-dabbrev-from-kill
        try-complete-file-name-partially
        try-complete-file-name
        try-expand-list
        try-expand-line
        try-complete-lisp-symbol-partially
        try-complete-lisp-symbol))
  :config
  ;; https://www.emacswiki.org/emacs/HippieExpand#h5o-9
  (defadvice he-substitute-string (after he-paredit-fix)
    "Remove extra paren when expanding line in paredit."
    (if (and paredit-mode (equal (substring str -1) ")"))
        (progn (backward-delete-char 1) (forward-char))))
  :bind
  ("C-M-/" . hippie-expand))

(use-package fancy-dabbrev
  :diminish
  :config
  (global-fancy-dabbrev-mode)
  :bind ("M-/" . fancy-dabbrev-expand))

(use-package emacs
  :init
  (setq completion-cycle-threshold 3)
  (setq tab-always-indent 'complete))

(use-package orderless
  :bind (:map minibuffer-local-completion-map
              ("C-l" . my/orderless-match-components-literally))
  :custom (orderless-component-separator 'orderless-escapable-split-on-space)
  :init
  (setq completion-styles '(orderless partial-completion basic)
        completion-category-defaults nil
        completion-category-overrides '((file (styles . (partial-completion orderless)))))

  (defun my/orderless-match-components-literally ()
    "Components match literally for the rest of the session."
    (interactive)
    (setq-local orderless-matching-styles '(orderless-literal)
                orderless-style-dispatchers nil))
  :config
  ;; Recognizes the following patterns:
  ;; * ~flex flex~
  ;; * =literal literal=
  ;; * %char-fold char-fold%
  ;; * `initialism initialism`
  ;; * !without-literal without-literal!
  ;; * .ext (file extension)
  ;; * regexp$ (regexp matching at end)
  (defun my/orderless-dispatch (pattern _index _total)
    (cond
     ;; Ensure that $ works with Consult commands, which add disambiguation suffixes
     ((string-suffix-p "$" pattern) `(orderless-regexp . ,(concat (substring pattern 0 -1) "[\x100000-\x10FFFD]*$")))
     ;; File extensions
     ((string-match-p "\\`\\.." pattern) `(orderless-regexp . ,(concat "\\." (substring pattern 1) "[\x100000-\x10FFFD]*$")))
     ;; Ignore single !
     ((string= "!" pattern) `(orderless-literal . ""))
     ;; Character folding
     ((string-prefix-p "%" pattern) `(char-fold-to-regexp . ,(substring pattern 1)))
     ((string-suffix-p "%" pattern) `(char-fold-to-regexp . ,(substring pattern 0 -1)))
     ;; Without literal
     ((string-prefix-p "!" pattern) `(orderless-without-literal . ,(substring pattern 1)))
     ((string-suffix-p "!" pattern) `(orderless-without-literal . ,(substring pattern 0 -1)))
     ;; Initialism matching
     ((string-prefix-p "`" pattern) `(orderless-initialism . ,(substring pattern 1)))
     ((string-suffix-p "`" pattern) `(orderless-initialism . ,(substring pattern 0 -1)))
     ;; Literal matching
     ((string-prefix-p "=" pattern) `(orderless-literal . ,(substring pattern 1)))
     ((string-suffix-p "=" pattern) `(orderless-literal . ,(substring pattern 0 -1)))
     ;; Flex matching
     ((string-prefix-p "~" pattern) `(orderless-flex . ,(substring pattern 1)))
     ((string-suffix-p "~" pattern) `(orderless-flex . ,(substring pattern 0 -1)))))
  ;; (setq orderless-matching-styles '(orderless-literal orderless-regexp orderless-strict-leading-initialism)
  ;;       orderless-style-dispatchers '(my/orderless-dispatch))
  (setq orderless-matching-styles '(orderless-literal orderless-regexp orderless-initialism)
        orderless-style-dispatchers '(my/orderless-dispatch)))

;; code completion - corfu
(use-package corfu
  ;; Optional customizations
  :custom
  (corfu-cycle t)            ;; Enable cycling for `corfu-next/previous'
  :bind (:map corfu-map
         ("TAB" . corfu-next)
         ([tab] . corfu-next)
         ("S-TAB" . corfu-previous)
         ([backtab] . corfu-previous))
  :init
  (global-corfu-mode))

(use-package corfu-doc
  :config
  (add-hook 'corfu-mode-hook #'corfu-doc-mode))

(use-package cape
  :bind (("C-c p p" . completion-at-point) ;; capf
         ("C-c p t" . complete-tag)        ;; etags
         ("C-c p d" . cape-dabbrev)        ;; or dabbrev-completion
         ("C-c p h" . cape-history)
         ("C-c p f" . cape-file)
         ("C-c p k" . cape-keyword)
         ("C-c p s" . cape-symbol)
         ("C-c p a" . cape-abbrev)
         ("C-c p i" . cape-ispell)
         ("C-c p l" . cape-line)
         ("C-c p w" . cape-dict)
         ("C-c p \\" . cape-tex)
         ("C-c p _" . cape-tex)
         ("C-c p ^" . cape-tex)
         ("C-c p &" . cape-sgml)
         ("C-c p r" . cape-rfc1345))
  :custom
  (cape-dict-file "/usr/share/dict/words")
  :init
  (add-to-list 'completion-at-point-functions #'cape-file t)
  (add-to-list 'completion-at-point-functions #'cape-dabbrev t)
  (add-to-list 'completion-at-point-functions #'cape-dict t)
  (add-to-list 'completion-at-point-functions #'cape-ispell t))

(provide 'init-completion)
;;; init-completion.el ends here