;;; my-github.el -- Github client -*- lexical-binding: t -*-

;; Copyright (C) 2023 Free Software Foundation.

;; Author: Yuchen Pei <id@ypei.org>
;; Package-Requires: ((emacs "28.2"))

;; This file is part of dotfiles.

;; dotfiles is free software: you can redistribute it and/or modify it under
;; the terms of the GNU Affero General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; dotfiles 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 Affero General
;; Public License for more details.

;; You should have received a copy of the GNU Affero General Public
;; License along with dotfiles.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;; Github client.

;;; Code:


(defun my-grok-github (url)
  "get github info of a project.
url is the url of the project
License; name; description; homepage; created at"
  (when (string-match "github.com\\(/[^/]+/[^/]+\\)/?.*$" url)
    (with-current-buffer (url-retrieve-synchronously
                          (concat "https://api.github.com/repos"
                                  (replace-regexp-in-string
                                   "\\.git$" "" (match-string 1 url))))
      (set-buffer-multibyte t)
      (my-delete-http-header)
      (my-grok-github-make-info (json-read)))))

(defun my-post-process-licensing-name (name)
  (cond ((equal name "MIT") "expat")
        (t name)))

(defun my-grok-github-make-info (raw)
  (list (cons "Title" (alist-get 'name raw))
        (cons "Description" (alist-get 'description raw))
        (cons "Source" (alist-get 'html_url raw))
        (cons "Website" (alist-get 'homepage raw))
        (cons "Released" (substring (alist-get 'created_at raw) 0 10))
        (cons "Pushed" (substring (alist-get 'pushed_at raw) 0 10))
        (cons "Subject" (string-join (alist-get 'topics raw) ", "))
        ;; FIXME: why did we comment this out?
        ;; (cons "License" (my-post-process-licensing-name
        ;;                  (alist-get 'spdx_id (alist-get 'license raw))))
        (cons "Developers" (my-grok-github-get-developer-name
                            (alist-get 'url (alist-get 'owner raw))))))

(defun my-grok-github-get-developer-name (url)
  (with-current-buffer (url-retrieve-synchronously url)
    (set-buffer-multibyte t)
    (my-delete-http-header)
    (alist-get 'name (json-read))))

;;; urls with github
;; TODO: generalise the following to common forges, including
;; savannah, cgit, gitlab etc.
(defun my-github-revision-url (file revision)
  "Returns the github url of the upstream repo containing FILE at REVISION."
  (let ((repo-url (vc-git-repository-url file))
        (revision (or revision (vc-working-revision default-directory))))
    (format "%s/commit/%s" repo-url revision)))

(defun my-github-kill-revision-url (revision)
  "Kill the github revision url for REVISION."
  (kill-new (my-github-revision-url revision)))

(defun my-github-file-loc-url (file-loc &optional revision)
  "Convert a file location to a github url."
  (pcase-let* ((`(,file ,line-no) (split-string file-loc ":"))
               (revision (or revision (vc-working-revision file))))
    (my-github-file-loc-url-internal file line-no revision)))

(defun my-github-file-loc-url-internal (file line-no revision)
  "Convert a FILE location at LINE-NO to a github url.

REVISION is the commit hash."
  (let* ((repo-url (vc-git-repository-url file))
         (repo-root (vc-git-root file))
         (path (file-relative-name file repo-root)))
    (format "%s/blob/%s/%s#L%s" repo-url revision path line-no)))

(defun my-github-kill-current-file-loc-url ()
  "Kill the github url from where the point is at."
  (interactive)
  (kill-new (my-github-file-loc-url-internal
             (buffer-file-name)
             (1+ (current-line))
             (vc-working-revision (buffer-file-name)))))

(defun my-org-backtrace-to-github (bt &optional revision)
  (string-join
   (mapcar
    (lambda (link)
      (string-match "\\[\\[\\(.*\\)\\]\\[\\(.*\\)\\]\\]" link)
      (let ((target (match-string 1 link))
            (label (match-string 2 link)))
        (format "[[%s][%s]]"
                (my-github-file-loc-url target revision)
                label)))
    (split-string bt " > "))
   " > "))

(defun my-org-backtrace-to-github-region (beg end)
  (interactive "r")
  (kill-new
   (my-org-backtrace-to-github (buffer-substring-no-properties beg end))))

(defun my-org-backtrace-to-github-slack (beg end)
  (interactive "r")
  (let ((bt (buffer-substring-no-properties beg end))
        (revision (when current-prefix-arg
                    (read-string "Rrevision: ")))
        )
    (with-temp-buffer
      (insert "#+options: ^:nil
")
      (goto-char (point-max))
      (insert (my-org-backtrace-to-github bt revision))
      (org-md-export-as-markdown))))

(provide 'my-github)
;;; my-github.el ends here