;;; sitemaps.el --- Sitemap generators for org-publish -*- lexical-binding: t; -*-

;;; Commentary:
;; Custom :sitemap-function implementations for each publishing project.
;;
;; NOTE: Do NOT define `site-root' here.  build-site.el owns that definition.

;;; Code:

(require 'cl-lib)
(require 'org)

;; ─────────────────────────────────────────────────────────────────────────────
;; Internal helpers
;; ─────────────────────────────────────────────────────────────────────────────

(defun z/sitemap--tag-html (tags-raw)
  "Convert a raw FILETAGS string into an Org-mode HTML inline tag list.
Returns an empty string when TAGS-RAW is nil or blank."
  (if (and tags-raw (string-match-p "\\S-" tags-raw))
      (mapconcat
       (lambda (tag)
         (format "@@html:<a href=\"/tags/%s.html\"><span class=\"post-tag\">%s</span></a>@@"
                 tag tag))
       (split-string tags-raw ":" t)
       " ")
    ""))

(defun z/hidden-page-p (file)
  "Return non-nil when FILE opts out of public index pages."
  (and (file-exists-p file)
       (with-temp-buffer
         (insert-file-contents file)
         (org-mode)
         (let ((value (cadr (assoc "HIDDEN_PAGE"
                                   (org-collect-keywords '("HIDDEN_PAGE"))))))
           (and value (string-match-p "^\\s-*t\\s-*$" (downcase value)))))))

(defun z/sitemap--link-file (link base-dir)
  "Return absolute file path from Org sitemap LINK under BASE-DIR."
  (when (and (stringp link)
             (string-match "\\[\\[file:\\([^]]+\\)\\]" link))
    (expand-file-name (match-string 1 link) base-dir)))

(defun z/sitemap--filter-hidden (node base-dir)
  "Remove nodes marked with #+HIDDEN_PAGE: t from sitemap NODE."
  (cond
   ((not (consp node)) node)
   ((let ((file (z/sitemap--link-file (car node) base-dir)))
      (and file (z/hidden-page-p file)))
    nil)
   (t
    (let ((children (delq nil
                          (mapcar (lambda (child)
                                    (z/sitemap--filter-hidden child base-dir))
                                  (cdr node)))))
      (cons (car node) children)))))

(defun z/main-sitemap (title list)
  "Default sitemap with hidden pages removed, plus an automatic Mermaid map."
  (let ((filtered (z/sitemap--filter-hidden list z/site-root)))
    (concat
     "#+TITLE: " title "\n"
     "#+OPTIONS: toc:nil num:nil\n\n"
     "#+begin_src mermaid\n"
     (z/sitemap--mermaid filtered)
     "\n#+end_src\n\n"
     "* Pages\n"
     (replace-regexp-in-string
      "\\`#\\+TITLE: .*\n+" ""
      (org-publish-sitemap-default title filtered)))))

(defun z/sitemap--mermaid-label (text)
  "Escape TEXT for a Mermaid quoted label."
  (replace-regexp-in-string
   "\"" "\\\\\""
   (replace-regexp-in-string
    "[\n\r\t ]+" " "
    (string-trim (or text "")))
   t t))

(defun z/sitemap--link-data (link)
  "Return (REL TITLE) from an Org sitemap LINK, or nil for directory nodes."
  (when (and (stringp link)
             (string-match "\\[\\[file:\\([^]]+\\)\\]\\[\\([^]]+\\)\\]\\]" link))
    (list (match-string 1 link)
          (match-string 2 link))))

(defun z/sitemap--html-href (rel)
  "Return published HTML href for Org path REL."
  (concat (file-name-sans-extension rel) ".html"))

(defun z/sitemap--mermaid (tree)
  "Render sitemap TREE as Mermaid flowchart source."
  (let ((counter 0)
        (lines nil)
        (clicks '()))
    (cl-labels
        ((next-id ()
                  (setq counter (1+ counter))
                  (format "n%d" counter))
         (node-label (node)
                     (let ((data (z/sitemap--link-data (car node))))
                       (if data
                           (cadr data)
                         (car node))))
         (walk (node parent)
               (when (consp node)
                 (if (not (stringp (car node)))
                     (dolist (child (cdr node))
                       (walk child parent))
                   (let* ((id (next-id))
                          (data (z/sitemap--link-data (car node)))
                          (label (z/sitemap--mermaid-label (node-label node)))
                          (children (cdr node))
                          (shape (if data "[\"%s\"]" "{{\"%s\"}}")))
                     (push (format "  %s%s" id (format shape label)) lines)
                     (push (format "  %s --> %s" parent id) lines)
                     (when data
                       (push (format "  click %s \"%s\" \"%s\""
                                     id
                                     (z/sitemap--html-href (car data))
                                     (z/sitemap--mermaid-label (cadr data)))
                             clicks))
                     (dolist (child children)
                       (walk child id)))))))
      (dolist (node (if (and (consp tree) (not (stringp (car tree))))
                        (cdr tree)
                      tree))
        (walk node "root")))
    (mapconcat #'identity
               (append
                '("flowchart TD"
                  "  root([\"zxh\"])")
                (nreverse lines)
                (nreverse clicks))
               "\n")))

(defun z/sitemap--entry-data (link base-dir)
  "Extract (FULL-PATH DATE-STR TAGS-STR) for a sitemap ENTRY under BASE-DIR.
LINK is the raw [[file:...][...]] string produced by org-publish."
  (let* ((filename  (if (string-match "\\[\\[file:\\([^]]+\\)\\]" link)
                        (match-string 1 link)
                      link))
         (full-path (expand-file-name filename base-dir))
         (date      (and (file-exists-p full-path)
                         (org-publish-find-date full-path org-publish-project-alist)))
         (date-str  (if date (format-time-string "%d-%m-%Y %H:%M" date) "no date"))
         (tags-raw  (and (file-exists-p full-path)
                         (with-temp-buffer
                           (insert-file-contents full-path)
                           (org-mode)
                           (cadr (assoc "FILETAGS"
                                        (org-collect-keywords '("FILETAGS"))))))))
    (list full-path date-str (z/sitemap--tag-html tags-raw) date)))

(defun z/sitemap--flat-list (title list base-dir section-title categories-rel)
  "Render a flat bullet-point sitemap.
TITLE          — org-publish title string
LIST           — the raw list from org-publish (car is root node)
BASE-DIR       — absolute path to the project's :base-directory
SECTION-TITLE  — heading text, e.g. \"Posts\"
CATEGORIES-REL — relative path to categories.html from this project root"
  (concat
   "#+TITLE: " title "\n"
   "#+OPTIONS: toc:nil num:nil\n\n"
   (format "See the categories: @@html:<a href=\"%s\">Categories</a>@@\n\n" categories-rel)
   "* " section-title "\n"
   (mapconcat
    (lambda (entry)
      (when (consp entry)
        (let* ((link (car entry))
               (data (z/sitemap--entry-data link base-dir))
               (date-str (nth 1 data))
               (tags-str (nth 2 data)))
          (format "- %s @@html:<span class=\"post-date\">%s</span>@@ %s"
                  link date-str tags-str))))
    (cdr list)
    "\n")))

;; ─────────────────────────────────────────────────────────────────────────────
;; Posts
;; ─────────────────────────────────────────────────────────────────────────────

(defun z/posts-sitemap (title list)
  "Flat sitemap for org-posts."
  (z/sitemap--flat-list title list
                         (site-path "posts/")
                         "Posts:"
                         "../home/categories.html"))

;; ─────────────────────────────────────────────────────────────────────────────
;; Blogs — flat (kept for compatibility, not used as default)
;; ─────────────────────────────────────────────────────────────────────────────

(defun z/blogs-sitemap (title list)
  "Flat sitemap for org-blogs (use z/blogs-grouped-sitemap for the default)."
  (z/sitemap--flat-list title list
                         (site-path "blogs/")
                         "Blogs:"
                         "../home/categories.html"))

;; ─────────────────────────────────────────────────────────────────────────────
;; Blogs — grouped by year → month
;; ─────────────────────────────────────────────────────────────────────────────

(defun z/blogs-grouped-sitemap (title list)
  "Sitemap for org-blogs grouped by year and month, newest first."
  (let ((data (make-hash-table :test 'equal)))

    ;; Collect into  year-key → month-key → list of (link date-str tags-str time)
    (dolist (entry (cdr list))
      (when (consp entry)
        (let* ((link      (car entry))
               (ed        (z/sitemap--entry-data link (site-path "blogs/")))
               (full-path (nth 0 ed))
               (date-str  (nth 1 ed))
               (tags-str  (nth 2 ed))
               (time      (nth 3 ed)))
          (when time
            (let* ((year  (format-time-string "%Y"    time))
                   (month (format-time-string "%B %Y" time))
                   (year-table (or (gethash year data)
                                   (puthash year (make-hash-table :test 'equal) data))))
              (puthash month
                       (cons (list link date-str tags-str time)
                             (gethash month year-table))
                       year-table))))))

    ;; Render
    (let ((output (concat "#+TITLE: " title "\n"
                          "#+OPTIONS: toc:nil num:nil\n\n"
                          "See the categories: @@html:<a href=\"../home/categories.html\">Categories</a>@@\n\n")))
      (dolist (year (sort (hash-table-keys data) #'string>))
        (setq output (concat output "* " year "\n"))
        (let ((year-table (gethash year data)))
          (dolist (month (sort (hash-table-keys year-table)
                               (lambda (a b)
                                 (time-less-p
                                  (date-to-time (concat "01 " b))
                                  (date-to-time (concat "01 " a))))))
            (setq output (concat output "\n** " month "\n"))
            (dolist (entry (sort (gethash month year-table)
                                 (lambda (a b)
                                   (time-less-p (nth 3 b) (nth 3 a)))))
              (setq output
                    (concat output
                            (format "- %s @@html:<span class=\"post-date\">%s</span>@@ %s\n"
                                    (nth 0 entry)
                                    (nth 1 entry)
                                    (nth 2 entry))))))))
      output)))

;; ─────────────────────────────────────────────────────────────────────────────
;; Year-scoped sitemaps (generic helper)
;; ─────────────────────────────────────────────────────────────────────────────

(defun z/year-grouped-sitemap (title list year base-dir categories-rel)
  "Generic year-scoped, month-grouped sitemap.
YEAR is a string like \"2025\".  BASE-DIR is the project root.
CATEGORIES-REL is the relative href to categories.html."
  (let ((output (concat "#+TITLE: " title "\n"
                        "#+OPTIONS: toc:nil num:nil\n\n"
                        (format "See the categories: @@html:<a href=\"%s\">Categories</a>@@\n\n"
                                categories-rel)
                        "* " year "\n"))
        (current-month nil))
    (dolist (entry (cdr list))
      (when (consp entry)
        (let* ((link      (car entry))
               (ed        (z/sitemap--entry-data link base-dir))
               (date-str  (nth 1 ed))
               (tags-str  (nth 2 ed))
               (time      (nth 3 ed))
               (month-str (if time (format-time-string "%B %Y" time) "No date")))
          (unless (equal month-str current-month)
            (setq current-month month-str)
            (setq output (concat output "\n** " month-str "\n")))
          (setq output
                (concat output
                        (format "- %s @@html:<span class=\"post-date\">%s</span>@@ %s\n"
                                link date-str tags-str))))))
    output))

(defun z/2025-sitemap (title list)
  "Sitemap for blogs/2025/ grouped by month."
  (z/year-grouped-sitemap title list "2025"
                           (site-path "blogs/2025/")
                           "../../home/categories.html"))

(defun z/2026-sitemap (title list)
  "Sitemap for blogs/2026/ grouped by month."
  (z/year-grouped-sitemap title list "2026"
                           (site-path "blogs/2026/")
                           "../../home/categories.html"))

;; ─────────────────────────────────────────────────────────────────────────────
;; Career
;; ─────────────────────────────────────────────────────────────────────────────

(defun z/career-sitemap (title list)
  "Sitemap for posts/career/ grouped by month."
  (concat
   (z/year-grouped-sitemap title list ""
                            (site-path "posts/career/")
                            "../../home/categories.html")
   "\nSee the following page for more details: @@html:<a href=\"./career-intro.html\">Career Intro</a>@@\n"))

;; ─────────────────────────────────────────────────────────────────────────────
;; Categories
;; ─────────────────────────────────────────────────────────────────────────────

(defun z/categories-sitemap (title _list)
  "Generate a categories overview by scanning tags across posts and blogs."
  (let* ((expanded (org-publish-expand-projects org-publish-project-alist))
         (posts    (assoc "org-posts" expanded))
         (blogs    (assoc "org-blogs" expanded))
         (files    (cl-remove-if
                    (lambda (f)
                      (member (file-name-nondirectory f)
                              '("posts-list.org" "blogs-list.org"
                                "sitemap.org"    "categories.org")))
                    (cl-remove-duplicates
                     (append (and posts (org-publish-get-base-files posts))
                             (and blogs (org-publish-get-base-files blogs)))
                     :test #'file-equal-p)))
         (counts   (make-hash-table :test 'equal)))
    (dolist (f files)
      (when (file-readable-p f)
        (with-temp-buffer
          (insert-file-contents f)
          (org-mode)
          (let* ((kw  (org-collect-keywords '("FILETAGS" "TAGS")))
                 (raw (cadr (or (assoc "FILETAGS" kw)
                                (assoc "TAGS"     kw)))))
            (when raw
              (dolist (tag (split-string raw ":" t))
                (puthash tag (1+ (gethash tag counts 0)) counts)))))))
    (let (tags)
      (maphash (lambda (k _) (push k tags)) counts)
      (setq tags (sort tags #'string-lessp))
      (concat
       "#+TITLE: " title "\n#+OPTIONS: toc:nil num:nil title:nil\n\n"
       "* Categories (Includes both blogs and posts)\n"
       (if tags
           (mapconcat
            (lambda (tag)
              (format "- [[file:../tags/%s.org][@@html:<span class=\"post-tag\">%s</span>@@]] (%d)"
                      (z/tag-slug tag) tag (gethash tag counts)))
            tags
            "\n")
         "_No tags found yet._")))))

(provide 'sitemaps)

;;; sitemaps.el ends here