;; -*- lexical-binding: t -*-
;;; ob-ein.el --- org-babel functions for template evaluation

;; Copyright (C) John M. Miller

;; Author: John M. Miller <millejoh at mac.com>
;;

;;; License:


;; This file is NOT part of GNU Emacs.

;; ob-ein.el 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.

;; ob-ein.el 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 ob-ein.el.  If not, see <http://www.gnu.org/licenses/>.

;;; Commentary:

;; Support executing org-babel source blocks using EIN worksheets.

;;; Credits:

;; Uses code from https://github.com/gregsexton/ob-ipython (MIT License)

;;; Code:
(require 'ob)
(require 'ein-utils)

(autoload 'org-element-property "org-element")
(autoload 'org-element-context "org-element")
(autoload 'ein:notebooklist-new-notebook-with-name "ein-notebooklist")
(autoload 'ein:notebooklist-login "ein-notebooklist")
(autoload 'ein:notebook-get-opened-notebook "ein-notebook")
(autoload 'ein:notebook-url "ein-notebook")
(autoload 'ein:notebook-open "ein-notebook")
(autoload 'ein:notebook-close "ein-notebook")
(autoload 'ein:process-url-or-port "ein-process")
(autoload 'ein:process-url-match "ein-process")
(autoload 'ein:process-refresh-processes "ein-process")
(autoload 'ein:jupyter-server-conn-info "ein-jupyter")
(autoload 'ein:jupyter-server-start "ein-jupyter")
(autoload 'ein:connect-buffer-to-notebook "ein-connect")
(autoload 'ein:connect-run-buffer "ein-connect")
(autoload 'ein:shared-output-get-cell "ein-shared-output")
(autoload 'ein:shared-output-eval-string "ein-shared-output")
(autoload 'ein:kernel-live-p "ein-kernel")
(autoload 'ein:query-singleton-ajax "ein:query")

(defvar *ob-ein-sentinel* "[....]"
  "Placeholder string replaced after async cell execution")

(defcustom ob-ein-timeout-seconds 600
  "Maximum seconds to wait for block to finish (for synchronous operations)."
  :type 'integer
  :group 'ein)

(defcustom ob-ein-languages
  '(("ein" . python)
    ("ein-python" . python)
    ("ein-R" . R)
    ("ein-r" . R)
    ("ein-julia" . julia)
    ("ein-hy" . hy))
  "ob-ein has knowledge of these (ein-LANG . LANG-MODE) pairs."
  :type '(repeat (cons string symbol))
  :group 'ein)

(defcustom ob-ein-anonymous-path ".%s.ipynb"
  "When session header doesn't specify ipynb, prosecute all interactions for a given language in this throwaway notebook (substitute %s with language)."
  :type '(string)
  :group 'ein)

(defsubst ob-ein-anonymous-p (path)
  "Return t if PATH looks like ob-ein-anonymous-path.  Fragile"
  (string-match (replace-regexp-in-string "%s" ".+"
                  (replace-regexp-in-string "\\." "\\\\." ob-ein-anonymous-path))
                path))

(defcustom ob-ein-inline-image-directory "ein-images"
  "Store ob-ein images here."
  :group 'ein
  :type '(directory))

(defcustom ob-ein-default-header-args:ein nil
  "No documentation."
  :group 'ein
  :type '(repeat string))

(defun ob-ein--inline-image-info (value)
  (let* ((f (md5 value))
         (d ob-ein-inline-image-directory)
         (tf (concat d "/ob-ein-" f ".png")))
    (unless (file-directory-p d)
      (make-directory d 'parents))
    tf))

(defun ob-ein--write-base64-image (img-string file)
  (with-temp-file file
    (let ((buffer-read-only nil)
          (buffer-file-coding-system 'binary)
          (require-final-newline nil)
          (file-precious-flag t))
      (insert img-string)
      (base64-decode-region (point-min) (point-max)))))

(defun ob-ein--return-mime-type (json file)
  (cl-loop
    for key in ein:output-types-text-preferred
    for type = (intern (format ":%s" key)) ; something like `:text'
    for value = (plist-get json type)      ; FIXME: optimize
    when (plist-member json type)
    return
      (cl-case key
        ((svg image/svg)
         (let ((file (or file (ob-ein--inline-image-info value))))
           (ob-ein--write-base64-image value file)
           (format "[[file:%s]]" file)))
        ((png image/png jpeg image/jpeg)
         (let ((file (or file (ob-ein--inline-image-info value))))
           (ob-ein--write-base64-image value file)
           (format "[[file:%s]]" file)))
        (t (plist-get json type)))))

(defun ob-ein--process-outputs (outputs params)
  (let ((file (cdr (assoc :image params))))
    (ein:join-str "\n"
                  (cl-loop for o in outputs
                    collecting (ob-ein--return-mime-type o file)))))


(defun ob-ein--get-name-create (src-block-info)
  "Get the name of a src block or add a uuid as the name."
  (if-let ((name (cl-fifth src-block-info)))
      name
    (save-excursion
      (let ((el (org-element-context))
            (id (org-id-new 'none)))
        (goto-char (org-element-property :begin el))
        (back-to-indentation)
        (split-line)
        (insert (format "#+NAME: %s" id))
        id))))

(defun ob-ein--babelize-lang (lang-name lang-mode)
  "Stand-up LANG-NAME as a babelized language with LANG-MODE syntax table.

Based on ob-ipython--configure-kernel."
  (add-to-list 'org-src-lang-modes `(,lang-name . ,lang-mode))
  (defvaralias (intern (concat "org-babel-default-header-args:" lang-name))
    'ob-ein-default-header-args:ein)
  (fset (intern (concat "org-babel-execute:" lang-name))
        `(lambda (body params)
           (require (quote ,(intern (format "ob-%s" lang-mode))) nil t)
           (if (boundp 'python-indent-guess-indent-offset-verbose)
               (setq python-indent-guess-indent-offset-verbose nil))
           (let* ((parser
                   (quote
                    ,(intern
                      (format "org-babel-variable-assignments:%s" lang-mode))))
                  (assignments (if (fboundp parser)
                                   (funcall (symbol-function parser) params)
                                 (ein:log 'verbose "%s: No suitable ob-%s module"
                                          (concat "org-babel-execute:" ,lang-name)
                                          (quote ,lang-mode))
                                 nil)))
             (ob-ein--execute-body body params assignments)))))

(defun ob-ein--execute-body (body params assignments)
  (let* ((buffer (current-buffer))
         (processed-params (org-babel-process-params params))
         (result-params (cdr (assq :result-params params)))
         (session (or (ein:aand (cdr (assoc :session processed-params))
                                (unless (string= "none" it)
                                  (format "%s" it)))
                      ein:url-localhost))
         (lang (nth 0 (org-babel-get-src-block-info)))
         (kernelspec (or (cdr (assoc :kernelspec processed-params))
                         (ein:aif (cdr (assoc lang org-src-lang-modes))
                             (cons 'language (format "%s" it))
                           (error "ob-ein--execute-body: %s not among %s"
                                  lang (mapcar #'car org-src-lang-modes)))))
         (name (ob-ein--get-name-create (org-babel-get-src-block-info)))
         (full-body (org-babel-expand-body:generic
                     (encode-coding-string body 'utf-8)
                     params
                     assignments))
         (callback (lambda (notebook)
                    (ob-ein--execute-async
                     buffer
                     full-body
                     (ein:$notebook-kernel notebook)
                     processed-params
                     result-params
                     name))))
    (save-excursion
      (cl-assert (not (stringp (org-babel-goto-named-src-block name))))
      (org-babel-insert-result *ob-ein-sentinel* result-params))
    (ob-ein--initiate-session session kernelspec callback)
    (if (ein:eval-if-bound 'org-current-export-file)
        (save-excursion
          (cl-loop with interval = 2000
            with pending = t
            repeat (/ (* ob-ein-timeout-seconds 1000) interval)
            do (progn
                 (org-babel-goto-named-result name)
                 (forward-line 1)
                 (setq pending (re-search-forward
                                (regexp-quote *ob-ein-sentinel*)
                                (org-babel-result-end) t)))
            until (not pending)
            do (sleep-for 0 interval)
            finally return
              (if pending
                  (progn
                    (ein:log 'error "ob-ein--execute-body: %s timed out" name)
                    "")
                (ob-ein--process-outputs
                 (ein:oref-safe (ein:shared-output-get-cell) 'outputs)
                 processed-params))))
      (org-babel-remove-result)
      *ob-ein-sentinel*)))

(defsubst ob-ein--execute-async-callback (buffer params result-params name)
  "Callback of 1-arity (the shared output cell) to update org buffer when
`ein:shared-output-eval-string' completes."
  (apply-partially
   (lambda (buffer* params* result-params* name* cell)
     (let* ((raw (ein:aif (ein:oref-safe cell 'traceback)
                     (ansi-color-apply (ein:join-str "\n" it))
                   (ob-ein--process-outputs
                    (ein:oref-safe cell 'outputs) params*)))
            (result
             (let ((tmp-file (org-babel-temp-file "ein-")))
               (with-temp-file tmp-file raw)
               (org-babel-result-cond result-params*
                 raw (org-babel-import-elisp-from-file tmp-file '(16)))))
            (info (org-babel-get-src-block-info 'light)))
       (ein:log 'debug "ob-ein--execute-async-callback %s \"%s\" %s" name* result buffer*)
       (save-excursion
         (save-restriction
           (with-current-buffer buffer*
             (unless (stringp (org-babel-goto-named-src-block name*)) ;; stringp=error
               (when info ;; kill #+RESULTS: (no-name)
                 (setf (nth 4 info) nil)
                 (org-babel-remove-result info))
               (org-babel-remove-result) ;; kill #+RESULTS: name
               (org-babel-insert-result
                result
                (cdr (assoc :result-params
                            (cl-third (org-babel-get-src-block-info)))))
               (org-redisplay-inline-images)))))))
   buffer params result-params name))

(defun ob-ein--execute-async (buffer body kernel params result-params name)
  "As `ein:shared-output-get-cell' is a singleton, ob-ein can only execute blocks
one at a time.  Further, we do not order the queued up blocks!"
  (deferred:$
    (deferred:next
      (deferred:lambda ()
        (let ((cell (ein:shared-output-get-cell)))
          (if (eq (slot-value cell 'callback) #'ignore)
              (let ((callback
                     (ob-ein--execute-async-callback buffer params
                                                     result-params name)))
                (setf (slot-value cell 'callback) callback))
            ;; still pending previous callback
            (deferred:nextc (deferred:wait 1200) self)))))
    (deferred:nextc it
      (lambda (_x)
        (ein:shared-output-eval-string kernel body nil)))))

(defun ob-ein--parse-session (session)
  (cl-multiple-value-bind (url-or-port _password) (ein:jupyter-server-conn-info)
    (let ((tokens (split-string session "/"))
          (parsed-url (url-generic-parse-url session)))
      (cond ((null (url-host parsed-url))
             (let* ((candidate (apply #'ein:url (car tokens) (cdr tokens)))
                    (parsed-candidate (url-generic-parse-url candidate))
                    (missing (url-scheme-get-property
                              (url-type parsed-candidate)
                              'default-port)))
               (if (and url-or-port
                        (= (url-port parsed-candidate) missing))
                   (apply #'ein:url url-or-port (cdr tokens))
                 candidate)))
            (t (ein:url session))))))

(defun ob-ein--initiate-session (session kernelspec callback &optional babel-info)
  "Retrieve notebook based on SESSION path and KERNELSPEC, starting jupyter instance
if necessary.  Install CALLBACK (i.e., cell execution) upon notebook retrieval."
  (let* ((nbpath (ob-ein--parse-session session))
         (info (or (org-babel-get-src-block-info) babel-info))
         (anonymous-path (format ob-ein-anonymous-path (nth 0 info)))
         (parsed-url (url-generic-parse-url nbpath))
         (slash-path (car (url-path-and-query parsed-url)))
         (path (if (string= slash-path "") anonymous-path
                 (substring slash-path 1)))
         (url-or-port (if (string= slash-path "")
                          nbpath
                        (substring nbpath 0 (- (length slash-path)))))
         (notebook (ein:notebook-get-opened-notebook url-or-port path))
         (callback-nbopen (lambda (nb _created)
                            (cl-loop repeat 50
                              for live-p = (ein:kernel-live-p (ein:$notebook-kernel nb))
                              until live-p
                              do (sleep-for 0 300)
                              finally
                              do (if (not live-p)
                                     (ein:log 'error
                                              "Kernel for %s failed to launch"
                                              (ein:$notebook-notebook-name nb))
                                   (funcall callback nb)))))
         (errback-nbopen (lambda (url-or-port status-code)
                           (if (eq status-code 404)
                               (ein:notebooklist-new-notebook-with-name
                                url-or-port kernelspec path callback-nbopen t))))
         (callback-login (lambda (_buffer url-or-port)
                           (ein:notebook-open url-or-port path kernelspec
                                              callback-nbopen errback-nbopen t))))
    (cond ((and notebook
                (string= path anonymous-path)
                (stringp kernelspec)
                (not (equal (ein:$kernelspec-name (ein:$notebook-kernelspec notebook))
                            kernelspec)))
           (ein:log 'debug "ob-ein--initiate-session: switching %s from %s to %s"
                    path (ein:$kernelspec-name (ein:$notebook-kernelspec notebook))
                    kernelspec)
           (cl-letf (((symbol-function 'y-or-n-p) #'ignore))
             (ein:notebook-close notebook)
             (ein:query-singleton-ajax
              (list 'ob-ein--initiate-session (ein:url url-or-port path))
              (ein:notebook-url notebook)
              :type "DELETE"))
           (cl-loop repeat 8
             for extant = (file-exists-p path)
             until (not extant)
             do (sleep-for 0 500)
             finally do (if extant
                            (ein:display-warning (format "cannot del %s" path))
                          (ob-ein--initiate-session session kernelspec callback))))
          (notebook (funcall callback notebook))
          ((string= (url-host parsed-url) ein:url-localhost)
           (ein:process-refresh-processes)
           (ein:aif (ein:process-url-match nbpath)
               (ein:notebooklist-login (ein:process-url-or-port it) callback-login)
             (ein:jupyter-server-start
              (executable-find (or (ein:eval-if-bound 'ein:jupyter-default-server-command)
                                   "jupyter"))
              (read-directory-name "Notebook directory: " default-directory)
              nil
              callback-login
              (let* ((port (url-port parsed-url))
                     (avoid (url-scheme-get-property (url-type parsed-url) 'default-port)))
                (cond ((= port avoid) nil)
                      (t (url-port parsed-url)))))))
          (t (ein:notebooklist-login url-or-port callback-login)))))

(defun ob-ein--edit-ctrl-c-ctrl-c ()
  "C-c C-c mapping in ein:connect-mode-map."
  (interactive)
  (if (not (org-src-edit-buffer-p))
      (ein:connect-run-buffer)
    (org-edit-src-save)
    (when (boundp 'org-src--beg-marker)
      (let* ((beg org-src--beg-marker)
             (buf (marker-buffer beg)))
        (with-current-buffer buf
          (save-excursion
            (goto-char beg)
            (org-ctrl-c-ctrl-c)))))))

(defcustom ob-ein-babel-edit-polymode-ignore nil
  "When false override default python mode key mapping for `\C-c\C-c' while inside a babel edit buffer.
Instead the binding will be to `ob-ein--edit-ctrl-c-ctrl-c', which will execute the code block being edited."
  :group 'ein
  :type '(boolean))

(defun org-babel-edit-prep:ein (babel-info)
  (if (and ein:polymode (not ob-ein-babel-edit-polymode-ignore))
      (progn
        (use-local-map (copy-keymap python-mode-map))
        (local-set-key "\C-c\C-c" 'ob-ein--edit-ctrl-c-ctrl-c))
    (let* ((buffer (current-buffer))
           (processed-parameters (nth 2 babel-info))
           (session (or (ein:aand (cdr (assoc :session processed-parameters))
                                  (unless (string= "none" it)
                                    (format "%s" it)))
                        ein:url-localhost))
           (lang (car babel-info))
           (kernelspec (or (cdr (assoc :kernelspec processed-parameters))
                           (ein:aif (cdr (assoc lang org-src-lang-modes))
                               (cons 'language (format "%s" it))
                             (error "ob-ein--execute-body: %s not among %s"
                                    lang (mapcar #'car org-src-lang-modes))))))
      (ob-ein--initiate-session
       session
       kernelspec
       (lambda (notebook)
         (ein:connect-buffer-to-notebook notebook buffer t)
         (define-key ein:connect-mode-map "\C-c\C-c" 'ob-ein--edit-ctrl-c-ctrl-c))
       babel-info))))

(defun org-babel-edit-prep:ein-python (babel-info)
  (org-babel-edit-prep:ein babel-info))

(cl-loop for (lang . mode) in ob-ein-languages
  do (ob-ein--babelize-lang lang mode))

;;;###autoload
(if (featurep 'org)
  (let* ((orig (get 'org-babel-load-languages 'custom-type))
         (orig-cdr (cdr orig))
         (choices (plist-get orig-cdr :key-type)))
    (push '(const :tag "Ein" ein) (nthcdr 1 choices))
    (put 'org-babel-load-languages 'custom-type
         (cons (car orig) (plist-put orig-cdr :key-type choices)))))

(provide 'ob-ein)