(require 'patch-sly)

(defun pure-env (&rest preserve-vars)
  "Return a pure `env' command as a list of string."
  (append '("env" "-i")
          (mapcar (lambda (var) (concat var "=" (getenv var)))
                  (append
                   '("DISPLAY"
                     "HOME"
                     "LOGNAME"
                     "TERM"
                     "USER")
                   preserve-vars))))

(defun ambrevar/delete-lisp-image-dump ()
  "Delete SLY current connection image dump.
This dump is expected to be generated by `lisp-repl-core-dumper'."
  (interactive)
  (let* ((pid (process-id (sly-inferior-process (sly-current-connection))))
         (args (alist-get 'args (process-attributes pid)))
         (command (car (split-string (alist-get 'args (process-attributes pid))))))
    (if (and (string= "image"
                      (file-name-extension command))
             (string= (file-name-directory command)
                      (expand-file-name "~/.cache/lisp-repl-core-directory/")))
        (when (yes-or-no-p (format "Delete %s?" command))
          (let ((delete-by-moving-to-trash nil))
            (delete-file command)
            (message "%S deleted." command)))
      (message "%S is not a Lisp image dump." command))))

(defun ambrevar/sbcl-for-nyxt (&optional refresh) ;; TODO: Run it in a container?
  "Fast, pure Guix environment for Nyxt development.
If REFRESH is non-nil, rebuild the environment."
  (cl-flet ((mtime (file)
                   (when (file-exists-p file)
                     (file-attribute-modification-time (file-attributes file)))))
    (let* ((root (expand-file-name "~/.guix-temp-profiles/nyxt/nyxt"))
           (guix-def (expand-file-name "~/common-lisp/nyxt/build-scripts/guix.scm"))
           (guix-sbcl-def (expand-file-name "~/common-lisp/nyxt/build-scripts/guix-sbcl-for-nyxt.scm"))
           (guix-checkout (format "/var/guix/profiles/per-user/%s/current-guix" (user-login-name))))
      (when (or refresh
                (not (file-exists-p root))
                (time-less-p (mtime root) (mtime guix-def))
                (time-less-p (mtime root) (mtime guix-sbcl-def))
                (time-less-p (mtime root) (mtime guix-checkout)))
        (make-directory (file-name-directory root) :parents)
        (call-process "guix" nil nil nil "package"
                      ;; May be needed to avoid having to rebuild some packages
                      ;; after the REPL has started.
                      "--no-grafts"
                      (concat "--profile=" root)
                      (concat "--install-from-file=" guix-sbcl-def))
        ;; Update root mtime in case it's not changed.
        ;; Can't use `set-file-times' on links.
        (call-process "touch" nil nil nil "-h" root))
      `((,@(pure-env "PERSONAL")
         ,(executable-find "bash") "--norc" "--noprofile" "-c"
         ,(concat (format "source '%s/etc/profile'" root)
                  " && sbcl"))))))

;; Warning: ,restart-lisp does not take changes into account, the buffer must be re-created.
(setq sly-lisp-implementations
      (let ((maybe-core-dumper (when-let ((exec (executable-find "lisp-repl-core-dumper")))
                                 (list exec))))
        `((sbcl-ambrevar ("lisp-repl-core-dumper" "-p" "ambrevar" "sbcl"
                          "--eval" "(in-package :ambrevar/all)"
                          "--eval" "(named-readtables:in-readtable clesh:syntax)"))
          (sbcl (,@maybe-core-dumper "sbcl"))
          (sbcl-failsafe ("sbcl"))
          (sbcl-nyxt (lambda () (ambrevar/sbcl-for-nyxt)))
          (sbcl-nyxt-refresh (lambda () (ambrevar/sbcl-for-nyxt :refresh)))
          ;; Simple REPL environment for Nyxt, in case sbcl-nyxt does not work.
          (sbcl-nyxt-failsafe ("guix" "environment" "--pure"
                               "--preserve=^PERSONAL$" ; To find personal config, like engines and bookmarks.
                               "-l" ,(expand-file-name "~/common-lisp/nyxt/build-scripts/guix.scm")
                               ;; glib is needed to export GIO_EXTRA_MODULES.
                               "--ad-hoc" "glib" "glib-networking" "gsettings-desktop-schemas"
                               "gnupg" "--" "sbcl"))
          (sbcl-nyxt-site ("guix" "environment" "--pure"
                           "-m" ,(expand-file-name "~/common-lisp/nyxt-site/guix-manifest.scm")
                           "--" "sbcl"))
          (ccl (,@maybe-core-dumper "ccl"))
          (clisp (,@maybe-core-dumper "clisp"))
          (ecl ("ecl")))))

(setq sly-connection-update-interval 0.1)

(when (require 'helm nil :noerror)
  (with-eval-after-load 'sly-mrepl
    (define-key sly-mrepl-mode-map (kbd "M-p") 'helm-comint-input-ring)
    (define-key sly-mrepl-mode-map (kbd "M-s f") 'helm-comint-prompts-all)
    (define-key sly-autodoc-mode-map (kbd "C-c C-d C-a") 'helm-sly-apropos)
    (define-key sly-mrepl-mode-map (kbd "C-c C-x c") 'helm-sly-list-connections)))

(when (require 'helm-sly nil :noerror)
  (when (require 'evil-collection nil :noerror)
    (evil-define-key '(normal insert) helm-sly-connections-map
      (kbd "S-<return>") 'helm-sly-run-go-to-repl-other-window))
  (defun ambrevar/helm-sly-format-connection (connection buffer)
    (let ((fstring "%s%2s  %s"))
      (format fstring
              (if (eq sly-default-connection connection)
                  "*"
                " ")
              (helm-sly-connection-number connection)
              (replace-regexp-in-string
               "*$" ""
               (replace-regexp-in-string "*sly-mrepl for " "" (buffer-name buffer))))))
  (setq helm-sly-connection-formatter #'ambrevar/helm-sly-format-connection)
  (global-helm-sly-mode)
  (add-to-list 'helm-source-names-using-follow "Lisp xrefs"))

(defun ambrevar/sly-insert-double-quotes ()
  "Convenient to write list of string, e.g. when writing a shell command line."
  (interactive)
  (while (sly-inside-string-p)
    (forward-char))
  (cycle-spacing)
  (insert "\"\"")
  (backward-char)
  (when (and (boundp 'evil-state)
             (not (eq evil-state 'insert)))
    (call-interactively #'evil-insert)))

(defun ambrevar/sly-insert-pipe ()
  "Convenient to write a `:<>' pipe."
  (interactive)
  (while (sly-inside-string-p)
    (forward-char))
  (newline-and-indent)
  (insert ":<>")
  (ambrevar/sly-insert-double-quotes))

(with-eval-after-load 'sly-mrepl
  (set-face-attribute 'sly-mrepl-output-face nil :inherit 'default :foreground)
  (setq sly-mrepl-history-file-name (expand-file-name "sly-mrepl-history" user-emacs-directory))
  ;; While `,i RET` is short enough, it's one more key away in Evil insert state:
  (define-key sly-mrepl-mode-map (kbd "C-c M-p") 'sly-mrepl-set-package)
  (define-key sly-mrepl-mode-map (kbd "C-c M-o") 'sly-mrepl-clear-repl)
  (define-key sly-mrepl-mode-map (kbd "S-SPC") 'ambrevar/sly-insert-double-quotes)
  (define-key sly-mrepl-mode-map (kbd "C-S-SPC") 'ambrevar/sly-insert-pipe))

(defun ambrevar/sly-load-reload-system ()
  (interactive)
  (funcall
   (if (sly-eval `(slynk-asdf:asdf-system-loaded-p ,(intern (sly-current-package))))
       #'sly-asdf-reload-system
     #'sly-asdf-load-system)
   (intern (sly-current-package))))
(define-key lisp-mode-map (kbd "<f6>") 'ambrevar/sly-load-reload-system)

(defun ambrevar/sly-colorize-buffer (str)
  "Useful for colorized output like the tests of Prove."
  (ansi-color-apply str))
(add-hook 'sly-mrepl-output-filter-functions 'ambrevar/sly-colorize-buffer)

(defun ambrevar/indent-and-helm-company (arg)
  "Indent then call `helm-company'.
Good substitute for `sly-mrepl-indent-and-complete-symbol'."
  (interactive "P")
  (indent-for-tab-command arg)
  (helm-company))

(setq sly-command-switch-to-existing-lisp 'always)
(add-hook 'sly-mrepl-hook #'ambrevar/init-lispy)
(add-hook 'sly-mrepl-hook #'rainbow-delimiters-mode)
;; REVIEW: With Emacs 27 we can:
;; (customize-set-variable 'helm-completion-style 'emacs)
;; (add-to-list 'completion-styles 'backend)
(when (require 'helm-sly nil 'noerror)
  ;; (add-hook 'sly-mrepl-hook #'helm-sly-disable-internal-completion)
  ;; REVIEW: Company completion has the benefit of having annotations.
  (when (require 'helm-company nil :noerror)
    (add-hook 'lisp-mode-hook #'company-mode)
    (define-key lisp-mode-map (kbd "<tab>") 'ambrevar/indent-and-helm-company)
    (define-key lisp-mode-map (kbd "M-<tab>") 'ambrevar/indent-and-helm-company)
    (defun ambrevar/sly-set-keys ()
      (define-key sly-mrepl-mode-map (kbd "<tab>") 'ambrevar/indent-and-helm-company)
      (define-key sly-mrepl-mode-map (kbd "M-<tab>") 'ambrevar/indent-and-helm-company))
    (add-hook 'sly-mrepl-hook #'ambrevar/sly-set-keys)
    (add-hook 'sly-mrepl-hook #'company-mode)))

(when (require 'helm-selector nil :noerror)
  (require 'init-sly-selector))

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Prompt customization
;; TODO: Upstream!

(defvar ambrevar/sly-status--last-command-time nil)
(make-variable-buffer-local 'ambrevar/sly-status--last-command-time)
(defun ambrevar/sly-status--record ()
  (setq ambrevar/sly-status--last-command-time (current-time)))

(defun ambrevar/sly-status-formatter (timestamp duration)
  "Return the status display for `ambrevar/sly-status'.
TIMESTAMP is the value returned by `current-time' and DURATION is the floating
time the command took to complete in seconds."
  (format "#[STATUS] End time %s, duration %.3fs\n"
          (format-time-string "%F %T" timestamp)
          duration))

(defcustom ambrevar/sly-status-min-duration 1
  "If a command takes more time than this, display its status with `ambrevar/sly-status'."
  :group 'sly
  :type 'number)

(defun ambrevar/sly-status (&optional formatter min-duration)
  "Termination timestamp and duration of command.
Status is only returned if command duration was longer than
MIN-DURATION \(defaults to `ambrevar/sly-status-min-duration').  FORMATTER
is a function of two arguments, TIMESTAMP and DURATION, that
returns a string."
  (if ambrevar/sly-status--last-command-time
      (let ((duration (time-to-seconds
                       (time-subtract (current-time) ambrevar/sly-status--last-command-time))))
        (setq ambrevar/sly-status--last-command-time nil)
        (if (> duration (or min-duration
                            ambrevar/sly-status-min-duration))
            (funcall (or formatter
                         #'ambrevar/sly-status-formatter)
                     (current-time)
                     duration)
          ""))
    (progn
      (advice-add 'sly-mrepl--send-input-sexp :after #'ambrevar/sly-status--record)
      "")))

(defun ambrevar/sly-prepare-prompt (old-func &rest args) ; TODO: Remove when upstream have merged `sly-mrepl-prompt-formatter'.
  (let ((package (nth 0 args))
        (new-prompt (format "%s%s\n%s"
                            (ambrevar/sly-status)
                            (abbreviate-file-name default-directory)
                            (nth 1 args)))
        (error-level (nth 2 args))
        (condition (nth 3 args)))
    (funcall old-func package new-prompt error-level condition)))

(cl-defun ambrevar/sly-new-prompt (_package
                                package-nickname
                                &key
                                entry-idx
                                error-level
                                &allow-other-keys)
  (concat
   (propertize (ambrevar/sly-status) 'font-lock-face 'font-lock-comment-face)
   "("
   (propertize (abbreviate-file-name default-directory) 'font-lock-face 'diff-added)
   ")\n"
   (propertize "<" 'font-lock-face 'sly-mrepl-prompt-face)
   (propertize (number-to-string entry-idx) 'font-lock-face 'sly-mode-line)
   (propertize ":" 'font-lock-face 'sly-mrepl-prompt-face)
   (propertize package-nickname 'font-lock-face 'sly-mode-line)
   (when (cl-plusp error-level)
     (concat (sly-make-action-button
              (format "[%d]" error-level)
              #'sly-db-pop-to-debugger-maybe)
             " "))
   (propertize "> " 'font-lock-face 'sly-mrepl-prompt-face)))

(with-eval-after-load 'sly-mrepl
  (if (boundp 'sly-mrepl-prompt-formatter)
      (setq sly-mrepl-prompt-formatter
            #'ambrevar/sly-new-prompt)
    (advice-add 'sly-mrepl--insert-prompt :around #'ambrevar/sly-prepare-prompt)))

(defun ambrevar/sly-mrepl-previous-prompt ()
  "Go to the beginning of the previous REPL prompt."
  (interactive)
  ;; This has two wrinkles around the first prompt: (1) when going to
  ;; the first prompt it leaves point at column 0 (1) when called from
  ;; frist prompt goes to beginning of buffer.  The correct fix is to
  ;; patch comint.el's comint-next-prompt and comint-previous-prompt
  ;; anyway...
  (let* ((inhibit-field-text-motion t)
         (pos (previous-single-char-property-change
               (previous-single-char-property-change (point)
                'sly-mrepl--prompt)
               'sly-mrepl--prompt)))
    (goto-char pos)
    (goto-char (line-beginning-position)))
  (end-of-line))

(defun ambrevar/sly-mrepl-next-prompt ()
  "Go to the beginning of the next REPL prompt."
  (interactive)
  (let ((pos (next-single-char-property-change (line-beginning-position 2)
                                               'sly-mrepl--prompt)))
    (goto-char pos)
    (if (get-text-property (point) 'sly-mrepl--prompt)
        (goto-char (next-single-char-property-change (point)
                                                     'sly-mrepl--prompt))
      (point))))

(advice-add 'sly-mrepl-next-prompt :override #'ambrevar/sly-mrepl-next-prompt)
(advice-add 'sly-mrepl-previous-prompt :override #'ambrevar/sly-mrepl-previous-prompt)

(provide 'init-sly)