;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2022 Jonathan Scoresby <me@jonscoresby.com>
;;;
;;; This file is part of GNU Guix.
;;;
;;; GNU Guix is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; GNU Guix is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.

(define-module (guix build vim-build-system)
  #:use-module ((guix build copy-build-system)
                #:prefix copy:)
  #:use-module (guix build utils)
  #:use-module (ice-9 match)
  #:use-module (ice-9 ftw)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-26)
  #:export (%standard-phases vim-build))

;; Commentary:
;;
;; System for installing vim and neovim plugins. It downloads
;; the source and copies the appropriate files to vim and nvim
;; packpaths. It then generates helptags.
;;
;; Code:

(define copy:install
  (assoc-ref copy:%standard-phases
             'install))

(define vim-path
  "/share/vim/vimfiles/pack/guix/")
(define nvim-path
  "/share/nvim/site/pack/guix/")

(define* (install #:key name
                  install-plan
                  neovim?
                  vim?
                  mode
                  outputs
                  #:allow-other-keys)

  (let* ((include-regexp '(".*\\/.*\\/.*"))
         (exclude-regexp '("scripts/.*" "tests?/.*" ".*\\/\\..*"))
         (vim-install (if vim?
                          `(("." ,(string-append vim-path mode "/" name "/")
                             #:include-regexp ,include-regexp
                             #:exclude-regexp ,exclude-regexp))
                          '()))
         (neovim-outputs (if vim?
                             `(("." ,(string-append nvim-path mode "/" name
                                                    "/")
                                #:include-regexp ,include-regexp
                                #:exclude-regexp ,exclude-regexp
                                #:output "neovim"))
                             `(("." ,(string-append nvim-path mode "/" name
                                                    "/")
                                #:include-regexp ,include-regexp
                                #:exclude-regexp ,exclude-regexp))))
         (neovim-install (if neovim? neovim-outputs
                             '())))
    (copy:install #:outputs outputs
                  #:install-plan (append vim-install neovim-install
                                         install-plan))))

(define* (generate-helptags #:key name
                            neovim?
                            vim?
                            mode
                            outputs
                            #:allow-other-keys)

  (define (vim-generate output)
    (invoke "vim" "--clean" "-en" "--cmd"
            (string-append "helptags "
                           output
                           vim-path
                           mode
                           "/"
                           name
                           "/doc | q")))

  (define (neovim-generate output)
    (invoke "nvim"
            "--clean"
            "--headless"
            "-en"
            "--cmd"
            (string-append "helptags "
                           output
                           nvim-path
                           mode
                           "/"
                           name
                           "/doc | q")))

  (when (scandir "./doc")
    (let ((out (assoc-ref outputs "out"))
          (neovim (assoc-ref outputs "neovim")))
      (if vim?
          (begin
            (vim-generate out)
            (if neovim?
                (neovim-generate neovim)))
          (neovim-generate out)))))

(define %standard-phases
  ;; Everything is as with the Copy Build System except for
  ;; the addition of the generate-helptags phase and a few
  ;; custom actions are added to the install phase
  (modify-phases copy:%standard-phases
    (replace 'install
      install)
    (add-after 'install 'generate-helptags
      generate-helptags)))

(define* (vim-build #:key inputs
                    (phases %standard-phases)
                    #:allow-other-keys #:rest args)
  "Build the given package, applying all of PHASES in order."
  (apply copy:copy-build
         #:inputs inputs
         #:phases phases
         args))

;;; vim-build-system.scm ends here