;;; tissue --- Text based issue tracker
;;; Copyright © 2022 Arun Isaac <arunisaac@systemreboot.net>
;;;
;;; This file is part of tissue.
;;;
;;; tissue 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.
;;;
;;; tissue 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 tissue.  If not, see <https://www.gnu.org/licenses/>.

(define-module (tissue tissue)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-9)
  #:use-module (srfi srfi-71)
  #:use-module (ice-9 match)
  #:use-module (tissue git)
  #:export (tissue-configuration
            tissue-configuration?
            tissue-configuration-project
            tissue-configuration-aliases
            tissue-configuration-indexed-documents
            tissue-configuration-web-css
            tissue-configuration-web-files
            gemtext-files-in-directory))

(define-record-type <tissue-configuration>
  (make-tissue-configuration project aliases indexed-documents
                             web-css web-files)
  tissue-configuration?
  (project delayed-tissue-configuration-project)
  (aliases delayed-tissue-configuration-aliases)
  (indexed-documents delayed-tissue-configuration-indexed-documents)
  (web-css delayed-tissue-configuration-web-css)
  (web-files delayed-tissue-configuration-web-files))

(define tissue-configuration-project
  (compose force delayed-tissue-configuration-project))

(define tissue-configuration-aliases
  (compose force delayed-tissue-configuration-aliases))

(define tissue-configuration-indexed-documents
  (compose force delayed-tissue-configuration-indexed-documents))

(define tissue-configuration-web-css
  (compose force delayed-tissue-configuration-web-css))

(define tissue-configuration-web-files
  (compose force delayed-tissue-configuration-web-files))

(define* (gemtext-files-in-directory #:optional directory)
  "Return a list of all gemtext files in @var{directory} tracked in the
current git repository. The returned paths are relative to the
top-level directory of the current repository and do not have a
leading slash.

If @var{directory} is unspecified, return the list of all gemtext
files tracked in the current git repository regardless of which
directory they are in."
  (filter (lambda (filename)
            (and (or (not directory)
                     (string-prefix? directory filename))
                 (string-suffix? ".gmi" filename)))
          (git-tracked-files (current-git-repository))))

(define-syntax define-lazy
  (lambda (x)
    "Define function that lazily evaluates all its arguments."
    (syntax-case x ()
      ((_ (name formal-args ...) body ...)
       (with-syntax ((delayed-formal-args
                      (map (lambda (formal-arg)
                             (syntax-case formal-arg ()
                               ((name default-value)
                                #'(name (delay default-value)))
                               (x #'x)))
                           #'(formal-args ...))))
         #`(define-syntax name
             (lambda (x)
               (with-ellipsis :::
                 (syntax-case x ()
                   ((_ args :::)
                    #`((lambda* delayed-formal-args
                         body ...)
                       #,@(map (lambda (arg)
                                 (if (keyword? (syntax->datum arg))
                                     arg
                                     #`(delay #,arg)))
                               #'(args :::)))))))))))))

(define-lazy (tissue-configuration #:key project (aliases '()) (indexed-documents '()) web-css (web-files '()))
  "Construct a <tissue-configuration> object. All arguments are
evaluated lazily.

@var{project} is the name of the project. It is used in the title of
the generated web pages, among other places.

@var{aliases} is a list of aliases used to refer to authors in the
repository. Each element is in turn a list of aliases an author goes
by, the first of which is the canonical name of that author.

@var{indexed-documents} is a list of @code{<indexed-document>} objects
representing documents to index.

@var{web-css} is the path to a CSS stylesheet. It is relative to the
document root and must begin with a @code{\"/\"}. If it is @code{#f},
no stylesheet is used in the generated web pages.

@var{web-files} is a list of @code{<file>} objects representing files to be
written to the web output.

All arguments to @code{tissue-configuration} are evaluated lazily."
   (make-tissue-configuration project aliases indexed-documents web-css web-files))