;; -*- lexical-binding: t -*-

(require 'ennum-html)
(require 'ennum-image)
(require 'ox)
(require 'seq)
(require 'cl)
(require 'loadhist)
(require 'map)
(require 'memoize)
(require 'simple-httpd)

(defvar ennum-version "0.1.0"
  "Ennum version string")

(defvar ennum-blog nil
  "Property list specifying ennum publish settings")

(defvar ennum-track-features
  '(ennum ennum-html ennum-image ob-tangle org ox ox-html)
  "List of features to track on expression evaluation.")

(defvar ennum-feature-hash
  nil
  "List of hashes tracking current state of features.")

;; TODO: Should the store have an absolute path to deal with directory
;; changes? Yes, since we ask for an absolute working directory, we
;; should.
(defun ennum-intern (filename)
  (let* ((store-item
          (expand-file-name (ennum-file-hash filename)
                            (ennum-setting :store)))
         (interned-path (expand-file-name (file-name-nondirectory filename)
                                          store-item)))
    (unless (file-exists-p store-item)
      (message "Interning %s in %s" filename store-item)
      (ennum-copy filename interned-path t)
      (ennum--set-file-modes-recursively store-item #o555 #o444 #o555))
    interned-path))

(defun ennum--hash ()
  "Return SHA256 hash of buffer contents encoded using
filename-safe base64 encoding. See RFC 4648§5. Briefly, this is a
variant of base64 encoding where characters + and / are replaced
respectively by - and _, and the pad character = is optional."
  (replace-regexp-in-string
   (rx (any ?+ ?/ ?=))
   (lambda (str)
     (pcase str
       ("+" "-")
       ("/" "_")
       ("=" "")))
   (base64-encode-string
    (secure-hash 'sha256 (current-buffer) nil nil t))))

(defun ennum-file-hash (file)
  (ennum--file-hash file (file-attribute-modification-time
                          (file-attributes file))))

(defmemoize ennum--file-hash (file last-modified)
  (with-temp-buffer
    ;; TODO: Use ennum-with-file-contents
    (set-buffer-multibyte nil)
    (insert-file-contents-literally file)
    (insert file)
    (ennum--hash)))

(defun ennum--feature-environment (feature)
  "Return hash of the current state of FEATURE.

The returned hash is the hash of the file providing FEATURE, and
the current state of all its variables."
  (pcase (feature-symbols feature)
    (`(,file . ,entries)
     (with-temp-buffer
       ;; Print hash of file.
       (print (ennum-file-hash file) (current-buffer))
       ;; Print variables and their values.
       (dolist (variable entries)
         (print (if (and (atom variable)
                         (boundp variable)
                         ;; Exclude `ennum-feature-hash' since it
                         ;; is meant to be changed on each run.
                         (not (eq variable 'ennum-feature-hash)))
                    (cons variable (symbol-value variable))
                  variable)
                (current-buffer)))
       (ennum--hash)))))

(defun ennum--set-file-modes-recursively (directory directory-mode file-mode executable-file-mode)
  (chmod directory directory-mode)
  (seq-do (lambda (file)
            (cond
             ((file-directory-p file) (chmod file directory-mode))
             ((file-executable-p file) (chmod file executable-file-mode))
             (t (chmod file file-mode))))
          (ennum-directory-files directory t t)))

(defmacro ennum-exp (&rest body)
  `(ennum-eval (lambda () ,@body)))

(defun ennum-eval (closure)
  (let ((output
         (expand-file-name
          (with-temp-buffer
            (let ((print-length nil)
                  (print-level nil))
              (print ennum-feature-hash (current-buffer))
              (print closure (current-buffer)))
            (ennum--hash))
          (ennum-setting :store))))
    ;; Create store if it doesn't exist
    (ennum-mkdir-p (ennum-setting :store))
    ;; Create store item if it doesn't already exist
    (unless (file-exists-p output)
      (message "Building %s" output)
      (ennum-with-temporary-directory temporary-directory
        (ennum-with-current-directory temporary-directory
          (funcall closure))
        (rename-file temporary-directory output))
      (ennum--set-file-modes-recursively output #o555 #o444 #o555))
    output))

(defun ennum-store-item-union (items)
  "Return a store item that is the union of ITEMS."
  (ennum-exp
   (seq-do (lambda (item)
             (seq-do (lambda (destination)
                       ;; TODO: Print warning about overwriting files?
                       (let ((source (expand-file-name destination item)))
                         (unless (file-exists-p destination)
                           (if (file-directory-p source)
                               (make-directory destination)
                             (copy-file source destination t)))))
                     (reverse (ennum-directory-files item nil t))))
           items)))

(defmacro ennum-make-functional-setter (name copier accessor)
  `(defun ,name (object new-value)
     (let ((object-copy (,copier object)))
       (setf (,accessor object-copy) new-value)
       object-copy)))

(cl-defstruct (ennum-post (:constructor ennum-make-post)
                          (:copier ennum-copy-post))
  filename slug author date language links tangle
  summary tags thumbnail title translation-group translations)

(ennum-make-functional-setter
 ennum-post-set-translations ennum-copy-post ennum-post-translations)

(ennum-make-functional-setter
 ennum-post-set-links ennum-copy-post ennum-post-links)

(cl-defstruct (ennum-link (:constructor ennum-make-link)
                          (:copier nil))
  type path)

(cl-defstruct (ennum-post-link (:constructor ennum-make-post-link)
                                (:copier ennum-copy-post-link)
                                (:include ennum-link (type 'post)))
  target-title)

(ennum-make-functional-setter
 ennum-post-link-set-target-title ennum-copy-post-link ennum-post-link-target-title)

(cl-defstruct (ennum-video-link (:constructor ennum-make-video-link)
                                (:copier nil)
                                (:include ennum-link (type 'video)))
  poster)

(defun ennum-posts (posts-directory)
  (sort (seq-mapcat
         ;; Set translations slot of post objects.
         (pcase-lambda (`(,_ . ,posts))
           (let ((translations
                  (seq-map (lambda (post)
                             (cons (ennum-post-language post)
                                   (ennum-post-slug post)))
                           posts)))
             (seq-map (lambda (post)
                        (ennum-post-set-translations
                         post
                         (seq-remove (pcase-lambda (`(,_ . ,slug))
                                       (string= (ennum-post-slug post) slug))
                                     translations)))
                      posts)))
         (let ((posts
                ;; Read posts from org files.
                (ennum--filter-map
                 (lambda (file)
                   (when (string= (file-name-extension file) "org")
                     (ennum-read-post file)))
                 (ennum-directory-files (ennum-setting :posts-directory)))))
           ;; Group posts by translation group.
           (seq-group-by
            'ennum-post-translation-group
            ;; Set target title slot of post links.
            (seq-map
             (lambda (post)
               (ennum-post-set-links
                post
                (seq-map (lambda (link)
                           (if (and (ennum-post-link-p link)
                                    (eq (ennum-post-link-target-title link) 'required))
                               (ennum-post-link-set-target-title
                                link
                                (seq-some (lambda (post)
                                            (when (string= (ennum-post-slug post)
                                                           (ennum-link-path link))
                                              (ennum-post-title post)))
                                          posts))
                             link))
                         (ennum-post-links post))))
             posts))))
        'ennum-later-post-p))

(defun ennum-later-post-p (post1 post2)
  (time-less-p (ennum-post-date post2)
               (ennum-post-date post1)))

(defun ennum-read-post (filename)
  (ennum--read-post
   filename (file-attribute-modification-time
             (file-attributes filename))))

(defmemoize ennum--read-post (filename last-modified)
  (ennum-with-file-contents filename
    (let ((metadata (org-export-get-environment 'ennum-html))
          (export (apply-partially 'org-export-with-backend 'ennum-html)))
      (seq-do (lambda (key)
                (unless (plist-member metadata key)
                  (user-error "Metadata %s not specified" key)))
              ennum-mandatory-metadata)
      (let* ((tree (org-element-parse-buffer))
             (links (org-element-map tree 'link
                      (lambda (link)
                        (pcase link
                          (`(link ,properties . ,_)
                           (let ((link-type (org-element-property :type link))
                                 (path (org-element-property :path link)))
                             (pcase link-type
                               ("post"
                                (ennum-make-post-link
                                 :path path
                                 :target-title (if (org-element-contents link)
                                                   'not-required 'required)))
                               ("video"
                                (ennum-make-video-link
                                 :path path
                                 :poster (ennum-video-poster path)))
                               (_ (ennum-make-link
                                   :type (intern link-type)
                                   :path path))))))))))
        (ennum-make-post
         :filename filename
         :slug (file-name-base filename)
         :author (when-let (author (plist-get metadata :author))
                   (funcall export (first author)))
         :date (org-timestamp-to-time (first (plist-get metadata :date)))
         :language (plist-get metadata :language)
         :links links
         ;; TODO: Deal with cases when the :tangle parameter is "yes"
         :tangle (seq-uniq
                  (org-element-map tree 'src-block
                    (lambda (src-block)
                      (pcase (org-babel-get-src-block-info nil src-block)
                        (`(,_ ,_ ,arguments ,_ ,_ ,_ ,_)
                         (let ((tangle-output-file (map-elt arguments :tangle)))
                           (pcase tangle-output-file
                             ("no" nil)
                             (_ tangle-output-file))))))))
         :summary (when-let (summary (plist-get metadata :summary))
                    (funcall export (first summary)))
         :tags (plist-get metadata :filetags)
         :thumbnail (or (plist-get metadata :thumbnail)
                        (seq-some (lambda (link)
                                    (let ((path (ennum-link-path link)))
                                      (pcase (ennum-link-type link)
                                        ('image path)
                                        ('video (ennum-video-poster path)))))
                                  links))
         :title (funcall export (first (plist-get metadata :title)))
         :translation-group (or (plist-get metadata :translation-group)
                                (file-name-base filename)))))))

(defvar ennum-mandatory-metadata
  (list :title :date))

(defmacro ennum-with-file-contents (file &rest body)
  "Create a temporary buffer, insert contents of FILE into that
buffer and evaluate BODY. The value returned is the value of the
last form in BODY."
  (declare (indent defun))
  `(with-temp-buffer
     (insert-file-contents ,file)
     ,@body))

(defun ennum-directory-files (directory &optional full include-directories)
  "Return recursively the list of all files under DIRECTORY. Files are
returned in depth first order.

If FULL is non-nil, absolute file names are returned. Else, the
file names are relative to DIRECTORY. If INCLUDE-DIRECTORIES is
non-nil, include directories in the output."
  (let ((files (directory-files-recursively
                directory (rx anything) include-directories)))
    (if full
        files
      (seq-map (apply-partially 'string-remove-prefix
                                ;; Expand directory in case it is a
                                ;; relative path.
                                (file-name-as-directory (expand-file-name directory)))
               files))))

(defun ennum--org-output-filename (filename)
  (concat (file-name-sans-extension filename) ".html"))

(defun ennum-export-post (post interned-org-file &optional output-html-file body-only)
  "Export INTERNED-ORG-FILE of POST to OUTPUT-HTML-FILE using the
ennum-html backend. INTERNED-ORG-FILE must be an org file
interned into the ennum store.

When optional argument BODY-ONLY is non-nil, only return body
code, without surrounding template. See `org-export-as'.

When optional argument OUTPUT-HTML-FILE is nil, return exported
result as a string."
  (let ((system-time-locale (map-elt (ennum-setting :locale-alist)
                                     (ennum-post-language post) nil 'string=))
        (ext-plist (list :ennum-post post)))
    (ennum-with-file-contents interned-org-file
      (cond
       (output-html-file
        (ennum-mkdir-p (file-name-directory output-html-file))
        (org-export-to-file 'ennum-html output-html-file nil nil nil body-only ext-plist))
       (t (org-export-as 'ennum-html nil nil body-only ext-plist))))))

(defun ennum-publish-post (post)
  (let ((interned-org-file (ennum-intern (ennum-post-filename post))))
    (append
     (list
      (ennum-exp
       (ennum-export-post post
                          interned-org-file
                          (ennum--org-output-filename (ennum-post-filename post)))))
     (when (ennum-post-tangle post)
       (list
        (ennum-exp
         ;; TODO: Handle tangle outputs that are nested
         ;; into directories, and when each tangle output
         ;; is nested into a different directory.
         (let* ((post-file-copy
                 (expand-file-name
                  (file-name-nondirectory interned-org-file)
                  (ennum-setting :static-directory))))
           (ennum-copy interned-org-file post-file-copy)
           (org-babel-tangle-file post-file-copy)
           (delete-file post-file-copy)))))
     (seq-mapcat 'ennum-publish-link (ennum-post-links post)))))

(defun ennum-publish-generic (other-files-directory file)
  (let ((interned-file (ennum-intern file)))
    (ennum-exp
     (let ((output-file
            (pcase (file-name-extension file)
              ("org" (ennum--org-output-filename file))
              (_ file))))
       (pcase (file-name-extension interned-file)
         ("org"
          (when (file-name-directory output-file)
            (ennum-mkdir-p (file-name-directory output-file)))
          (ennum-with-file-contents interned-file
            (org-export-to-file 'html output-file)))
         (_ (ennum-copy interned-file output-file)))))))

(defun ennum-video-poster (video)
  (or (seq-some (lambda (file)
                  (and (string= (file-name-base file)
                                (file-name-base video))
                       (file-name-nondirectory file)))
                (ennum-directory-files (ennum-setting :images-directory)))
      (user-error "Poster for %s not found" video)))

(defun ennum-add-tongue-suffix (filename tongue)
  (pcase tongue
    ("en" filename)
    (_ (format "%s.%s%s"
               (file-name-sans-extension filename)
               tongue
               (file-name-extension filename t)))))

(defun ennum-index-filename (filename-prefix tongue &optional extension page-number)
  (let ((extension (if extension (concat "." extension) "")))
    (ennum-add-tongue-suffix
     (if page-number
         (format "%s-%s%s" filename-prefix page-number extension)
       (concat filename-prefix extension))
     tongue)))

(defun ennum-publish-index-page (filename-prefix title last-page posts page-number output-file)
  (ennum-exp
   (let* ((tongue (ennum-post-language (first posts)))
          (system-time-locale
           (map-elt (ennum-setting :locale-alist)
                    tongue nil 'string=)))
     (when (file-name-directory output-file)
       (ennum-mkdir-p (file-name-directory output-file)))
     (with-temp-buffer
       (insert (format "#+TITLE: %s\n" title))
       (insert (format "#+LANGUAGE: %s\n" tongue))
       (insert "#+OPTIONS: num:nil toc:nil\n\n")
       (seq-do (lambda (post)
                 (insert (format "* [[post:%s][%s]]\n"
                                 (ennum-post-slug post)
                                 (ennum-post-title post)))
                 (insert (format-time-string "/%b %e, %Y/\n\n" (ennum-post-date post)))
                 (when-let ((thumbnail (ennum-post-thumbnail post)))
                   (insert (format "[[thumbnail:%s]]\n\n" thumbnail)))
                 (when-let ((summary (ennum-post-summary post)))
                   (insert summary)
                   (insert "\n\n"))
                 (when-let ((tags (ennum-post-tags post)))
                   (insert "Tags: ")
                   (insert
                    (string-join
                     (seq-map (lambda (tag)
                                (format "[[tag:%s][%s]]" (ennum-add-tongue-suffix tag tongue) tag))
                              tags)
                     ", "))
                   (insert "\n\n")))
               posts)
       (unless (= page-number 1)
         (insert (format "[[./%s][Newer posts]]\n\n"
                         (ennum-index-filename (file-name-nondirectory filename-prefix)
                                               tongue nil (1- page-number)))))
       (unless last-page
         (insert (format "[[./%s][Older posts]]\n"
                         (ennum-index-filename (file-name-nondirectory filename-prefix)
                                               tongue nil (1+ page-number)))))
       (org-export-to-file 'html output-file)))))

(defun ennum-publish-index-home (first-index-page-output filename-prefix tongue)
  (ennum-exp
   (ennum-copy (ennum--file-join first-index-page-output
                                 (ennum-index-filename filename-prefix tongue "html" 1))
               (ennum-add-tongue-suffix (format "%s.html" filename-prefix) tongue))))

(defun ennum-publish-index (filename-prefix title posts-per-page posts)
  (let* ((tongue (ennum-post-language (first posts)))
         (number-of-pages (ceiling (length posts) posts-per-page))
         (page-numbers (number-sequence 1 number-of-pages))
         (output-files (seq-map (apply-partially
                                 'ennum-index-filename filename-prefix tongue "html")
                                page-numbers))
         (outputs (seq-mapn (lambda (post page-number output-file)
                              (ennum-publish-index-page
                               filename-prefix title
                               (= page-number number-of-pages)
                               post page-number output-file))
                            (seq-partition posts posts-per-page)
                            page-numbers
                            output-files)))
    (cons (ennum-publish-index-home (first outputs) filename-prefix tongue)
          outputs)))

(defun ennum--absolute-uri (path)
  (format "%s://%s/%s"
          (ennum-setting :blog-scheme)
          (ennum-setting :blog-domain)
          path))

(defun ennum--atom-date (date)
  (format-time-string "%Y-%m-%dT%H:%M:%SZ" date))

(defun ennum-publish-feed (feed-file title rights posts)
  (let ((interned-post-files
         (seq-map (lambda (post)
                    (ennum-intern (ennum-post-filename post)))
                  posts)))
    (ennum-exp
     (message "Writing %s" feed-file)
     ;; TODO: Create ennu-mkdir-p-for-file
     (when (file-name-directory feed-file)
       (ennum-mkdir-p (file-name-directory feed-file)))
     (with-temp-file feed-file
       (insert
        (xmlgen
         `(feed :xmlns "http://www.w3.org/2005/Atom"
                (id ,(ennum--absolute-uri ""))
                (title ,title)
                (updated ,(ennum--atom-date (ennum-post-date (first posts))))
                (link :rel "self" :href ,(ennum--absolute-uri feed-file))
                (generator
                 ,(format "Emacs %d.%d Org-mode %s ennum %s"
                          emacs-major-version emacs-minor-version (org-version) ennum-version))
                (rights ,rights)
                ,@(seq-mapn (lambda (post interned-post-file)
                              (ennum--feed-entry post interned-post-file))
                            posts interned-post-files))))))))

(defun ennum--feed-entry (post interned-post-file)
  (let ((link (ennum--absolute-uri (ennum--org-output-filename
                                   (ennum-post-filename post)))))
    `(entry (id ,link)
            (title :xml:lang ,(ennum-post-language post) ,(ennum-post-title post))
            (updated ,(ennum--atom-date (ennum-post-date post)))
            ,@(when org-export-with-author
                `((author
                   (name ,(ennum-post-author post))
                   (email ,user-mail-address))))
            (content :type "html" :xml:lang ,(ennum-post-language post)
                     ,(ennum-export-post post interned-post-file nil t))
            (link :rel "alternate" :href ,link)
            ,@(seq-map (lambda (tag) `(category :term ,tag))
                       (ennum-post-tags post)))))

(defun ennum-setting (property)
  (pcase property
    ((or :blog-domain :blog-license :blog-title
         :images-directory :output-directory :posts-directory
         :static-directory :tag-directory :video-directory
         :working-directory)
     (or (plist-get ennum-blog property)
         (user-error "Property %s not defined" property)))
    ((or :atom-feed-number-of-posts :atom-feed-file
         :blog-scheme :default-image-width
         :image-link-width :index-posts-per-page
         :locale-alist :other-files-directory
         :store :tag-directory :thumbnail-image-width)
     (plist-get (org-combine-plists
                 (list :atom-feed-number-of-posts 12
                       :atom-feed-file "blog.atom"
                       :blog-scheme "https"
                       :default-image-width 640
                       :image-link-width 1024
                       :index-posts-per-page 12
                       :locale-alist '(("en" . "C"))
                       :store ".ennum"
                       :tag-directory "tag"
                       :thumbnail-image-width 320)
                 ennum-blog)
                property))
    (_ (error "Unknown property %s" property))))

(defun ennum-image-output-filename (image width)
  (format "%s-%spx.%s"
          (file-name-sans-extension image)
          width (file-name-extension image)))

(defun ennum--file-join (&rest components)
  (string-join
   (seq-map (lambda (component)
              (string-remove-suffix "/" (file-name-as-directory component)))
            components)
   "/"))

(defun ennum-publish-image (image width)
  (let ((interned-image (ennum-intern image)))
    (ennum-exp
     (message "Resizing %s to width %s" image width)
     (ennum-mkdir-p (ennum-setting :images-directory))
     (ennum-image-optimize-image
      (ennum-image-resize-image
       interned-image
       (ennum--file-join
        (ennum-setting :images-directory)
        (ennum-image-output-filename
         (file-name-nondirectory interned-image) width))
       width)))))

(defun ennum-publish-copy (file)
  (let ((interned-file (ennum-intern file)))
    (ennum-exp (ennum-copy interned-file file))))

(defun newest-file (files)
  (pcase files
    (`(,head . ,tail)
     (seq-reduce (lambda (file1 file2)
                   (if (file-newer-than-file-p file1 file2)
                       file1 file2))
                 tail head))))

(defun ennum-mkdir-p (directory)
  (make-directory directory t))

(defun ennum-copy (source destination &optional quiet)
  "Copy file or directory from SOURCE to DESTINATION. Overwrite
if DESTINATION already exists."
  (unless quiet
    (message "Copying %s to %s" source destination))
  (if (file-directory-p source)
      (copy-directory source destination)
    (when (file-name-directory destination)
      (ennum-mkdir-p (file-name-directory destination)))
    (copy-file source destination t)))

(defun ennum--filter-map (function sequence)
  (seq-filter 'identity (seq-map function sequence)))

(defun ennum-publish-link (link)
  (pcase (ennum-link-type link)
    ('image
     (seq-map (lambda (width)
                (ennum-publish-image
                 (ennum--file-join (ennum-setting :images-directory)
                                   (ennum-link-path link))
                 width))
              (list (ennum-setting :default-image-width)
                    (ennum-setting :image-link-width))))
    ('static
     (list
      (ennum-publish-copy
       (ennum--file-join (ennum-setting :static-directory)
                         (ennum-link-path link)))))
    ('video
     (seq-map 'ennum-publish-copy
              (list
               (ennum--file-join (ennum-setting :video-directory)
                                 (ennum-link-path link))
               (ennum--file-join (ennum-setting :images-directory)
                                 (ennum-video-link-poster link)))))))

(defmacro ennum-with-current-directory (directory &rest body)
  "Change to DIRECTORY, evaluate BODY and restore the current
working directory. The value returned is the value of the last
form in BODY."
  (declare (indent defun))
  (let ((current-directory-symbol (make-symbol "current-directory")))
    `(let ((,current-directory-symbol default-directory))
       (unwind-protect (progn (cd ,directory) ,@body)
         (cd ,current-directory-symbol)))))

(defmacro ennum-with-temporary-directory (temporary-directory &rest body)
  "Create temporary directory, evaluate BODY with the absolute
path of that directory assigned to TEMPORARY-DIRECTORY and
finally delete the temporary directory. The value returned is the
value of the last form in BODY."
  (declare (indent defun))
  `(let ((,temporary-directory (make-temp-file "ennum" t)))
     (unwind-protect
         (progn ,@body)
       (delete-directory ,temporary-directory t))))

(defun ennum-assoc-delete (key alist)
  "Delete KEY from ALIST.

Delete all occurrences of KEY in ALIST. This function is purely
functional. ALIST is not mutated."
  (seq-remove (pcase-lambda (`(,entry-key . ,_))
                (equal entry-key key))
              alist))

(defun ennum-assoc-set (key value alist)
  "Associate KEY with VALUE in ALIST.

This function is purely functional. ALIST is not mutated. Keys
are compared using `equal'."
  (cl-acons key value (ennum-assoc-delete key alist)))

(defun ennum-assoc-prepend (key value alist)
  "Prepend VALUE to that associated with KEY in ALIST.

This function is purely funcion. ALIST is not mutated."
  (ennum-assoc-set key
                   (cons value (map-elt alist key nil 'equal))
                   alist))

(defun ennum-many-to-many-group-by (function sequence)
  "Apply FUNCTION to each element of SEQUENCE.
Separate the elements of SEQUENCE into an alist using the results
as keys. Keys are compared using `equal'."
  (seq-reduce (lambda (result element)
                (seq-reduce (lambda (result key)
                              (ennum-assoc-prepend key element result))
                            (funcall function element)
                            result))
              (seq-reverse sequence)
              nil))

(defun ennum-publish ()
  (interactive)
  ;; Recompute feature hash.
  (setq ennum-feature-hash
        (seq-map 'ennum--feature-environment ennum-track-features))
  (ennum-with-current-directory (ennum-setting :working-directory)
    (let* ((blog-title (ennum-setting :blog-title))
           (posts (ennum-posts (ennum-setting :posts-directory)))
           (posts-per-page (ennum-setting :index-posts-per-page))
           (other-files-directory (ennum-setting :other-files-directory))
           (result
            (ennum-store-item-union
             (append
              ;; Publish posts
              (seq-mapcat 'ennum-publish-post posts)
              ;; Publish feed
              (list (ennum-publish-feed (ennum-setting :atom-feed-file)
                                        blog-title
                                        (ennum-setting :blog-license)
                                        (seq-take posts (ennum-setting :atom-feed-number-of-posts))))
              ;; Publish indices
              (seq-mapcat
               (pcase-lambda (`(,tongue . ,posts))
                 (ennum-publish-index "index" blog-title posts-per-page posts))
               (seq-group-by 'ennum-post-language posts))
              ;; Publish tag indices
              (seq-mapcat
               (pcase-lambda (`(,tag . ,posts))
                 (seq-mapcat
                  (pcase-lambda (`(,tongue . ,posts))
                    (ennum-publish-index
                     (ennum--file-join (ennum-setting :tag-directory) tag)
                     tag posts-per-page posts))
                  (seq-group-by 'ennum-post-language posts)))
               (ennum-many-to-many-group-by 'ennum-post-tags posts))
              ;; Publish thumbnails
              (seq-map (lambda (image)
                         (ennum-publish-image
                          (ennum--file-join (ennum-setting :images-directory) image)
                          (ennum-setting :thumbnail-image-width)))
                       (ennum--filter-map 'ennum-post-thumbnail posts))
              ;; Publish other files
              (seq-map (apply-partially 'ennum-publish-generic other-files-directory)
                       (ennum-directory-files other-files-directory))))))
      ;; Replace old output directory
      (when (file-exists-p (ennum-setting :output-directory))
        (ennum--set-file-modes-recursively (ennum-setting :output-directory) #o755 #o644 #o755)
        (delete-directory (ennum-setting :output-directory) t))
      (copy-directory result (ennum-setting :output-directory))
      (message "Ennum published to %s" (expand-file-name (ennum-setting :output-directory))))))

;;; Server
;;;
;;; Test HTTP server to serve the blog locally

;; TODO: Why can't simple-httpd itself handle the unhexing?
(defun ennum-server-start ()
  (interactive)
  (setq httpd-root (expand-file-name (ennum-setting :output-directory)
                                     (ennum-setting :working-directory)))
  (defun httpd/ (proc uri-path query request)
    (let* ((uri-path (httpd-unhex uri-path))
           (file-path (httpd-gen-path uri-path)))
      (cond
       ;; If a HTML file other than index.html was requested, reject
       ;; that request.
       ((and (not (string= (file-name-nondirectory file-path) "index.html"))
             (string= (file-name-extension file-path) "html"))
        (httpd-error proc 404))
       ;; If the requested file was found, serve it.
       ((= (httpd-status file-path) 200)
        (httpd-serve-root proc httpd-root uri-path request))
       ;; Perhaps, this is a post or other HTML file that is being
       ;; requested. Try serving a file with a .html extension
       ;; appended.
       (t (httpd-serve-root proc httpd-root (concat uri-path ".html") request)))))
  (httpd-start)
  (message "Ennum web server listening at http://localhost:%d" httpd-port))

(defun ennum-server-stop ()
  (interactive)
  (httpd-stop)
  (message "Ennum web server stopped"))

(provide 'ennum)