(*
 * Copyright (c) 2014, OCaml.org project
 * Copyright (c) 2015 KC Sivaramakrishnan <sk826@cl.cam.ac.uk>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *)

(** Feed format conversion and export. *)

module Atom = struct
  let entry_of_post post =
    let content = Syndic.Atom.Html (None, Post.content post) in
    let contributors =
      [ Syndic.Atom.author ~uri:(Uri.of_string (Source.url (Feed.source (Post.feed post))))
          (Source.name (Feed.source (Post.feed post))) ]
    in
    let links =
      match Post.link post with
      | Some l -> [ Syndic.Atom.link ~rel:Syndic.Atom.Alternate l ]
      | None -> []
    in
    let id =
      match Post.link post with
      | Some l -> l
      | None -> Uri.of_string (Digest.to_hex (Digest.string (Post.title post)))
    in
    let authors = (Syndic.Atom.author ~email:(Post.email post) (Post.author post), []) in
    let title : Syndic.Atom.text_construct = Syndic.Atom.Text (Post.title post) in
    let updated =
      match Post.date post with
      (* Atom entry requires a date but RSS2 does not. So if a date
       * is not available, just capture the current date. *)
      | None -> Ptime.of_float_s (Unix.gettimeofday ()) |> Option.get
      | Some d -> d
    in
    let categories =
      List.map (fun tag -> Syndic.Atom.category tag) (Post.tags post)
    in
    Syndic.Atom.entry ~content ~contributors ~links ~id ~authors ~title ~updated ~categories
      ()

  let entries_of_posts posts = List.map entry_of_post posts

  let feed_of_entries ~title ?id ?(authors = []) entries =
    let feed_id = match id with
      | Some i -> Uri.of_string i
      | None -> Uri.of_string "urn:river:merged"
    in
    let feed_authors = List.map (fun (name, email) ->
      match email with
      | Some e -> Syndic.Atom.author ~email:e name
      | None -> Syndic.Atom.author name
    ) authors in
    {
      Syndic.Atom.id = feed_id;
      title = Syndic.Atom.Text title;
      updated = Ptime.of_float_s (Unix.time ()) |> Option.get;
      entries;
      authors = feed_authors;
      categories = [];
      contributors = [];
      generator = Some {
        Syndic.Atom.version = Some "1.0";
        uri = None;
        content = "River Feed Aggregator";
      };
      icon = None;
      links = [];
      logo = None;
      rights = None;
      subtitle = None;
    }

  let to_string feed =
    let output = Buffer.create 4096 in
    Syndic.Atom.output feed (`Buffer output);
    Buffer.contents output
end

module Rss2 = struct
  let of_feed feed =
    (* Feed content is now always JSONFeed - cannot extract RSS2 directly *)
    (* This function is kept for backwards compatibility but always returns None *)
    let _ = feed in
    None
end

module Jsonfeed = struct
  let item_of_post post =
    (* Convert HTML content back to string *)
    let html = Post.content post in
    let content = `Html html in

    (* Create author *)
    let authors =
      if Post.author post <> "" then
        let author = Jsonfeed.Author.create ~name:(Post.author post) () in
        Some [author]
      else
        None
    in

    (* Create item *)
    Jsonfeed.Item.create
      ~id:(Post.id post)
      ~content
      ?url:(Option.map Uri.to_string (Post.link post))
      ~title:(Post.title post)
      ?summary:(Post.summary post)
      ?date_published:(Post.date post)
      ?authors
      ~tags:(Post.tags post)
      ()

  let items_of_posts posts = List.map item_of_post posts

  let feed_of_items ~title ?home_page_url ?feed_url ?description ?icon ?favicon items =
    Jsonfeed.create ~title ?home_page_url ?feed_url ?description ?icon ?favicon ~items ()

  let feed_of_posts ~title ?home_page_url ?feed_url ?description ?icon ?favicon posts =
    let items = items_of_posts posts in
    feed_of_items ~title ?home_page_url ?feed_url ?description ?icon ?favicon items

  let to_string ?(minify = false) jsonfeed =
    match Jsonfeed.to_string ~minify jsonfeed with
    | Ok s -> Ok s
    | Error err -> Error (Jsont.Error.to_string err)

  let of_feed feed =
    (* Feed content is now always River_jsonfeed.t - extract the inner Jsonfeed.t *)
    let jsonfeed_content = Feed.content feed in
    Some jsonfeed_content.River_jsonfeed.feed
end

module Html = struct
  (** HTML static site generation. *)

  let css = {|
* { margin: 0; padding: 0; box-sizing: border-box; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  line-height: 1.5;
  color: #333;
  background: #fff;
  max-width: 900px;
  margin: 0 auto;
  padding: 15px;
}

header {
  border-bottom: 1px solid #e1e4e8;
  padding-bottom: 10px;
  margin-bottom: 20px;
}

header h1 {
  font-size: 22px;
  font-weight: 600;
  margin-bottom: 6px;
}

header h1 a {
  color: #333;
  text-decoration: none;
}

nav {
  font-size: 13px;
}

nav a {
  color: #586069;
  text-decoration: none;
  margin-right: 12px;
}

nav a:hover {
  color: #0366d6;
}

.post {
  margin-bottom: 30px;
  padding-bottom: 25px;
  border-bottom: 1px solid #e1e4e8;
  overflow: hidden;
}

.post:last-child {
  border-bottom: none;
}

.author-thumbnail {
  float: right;
  width: 64px;
  height: 64px;
  border-radius: 50%;
  object-fit: cover;
  margin-left: 15px;
  margin-bottom: 10px;
  border: 2px solid #e1e4e8;
  transition: transform 0.2s, box-shadow 0.2s;
}

.author-thumbnail:hover {
  transform: scale(1.05);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.post-title {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 4px;
  line-height: 1.3;
}

.post-title a {
  color: #0366d6;
  text-decoration: none;
}

.post-title a:hover {
  text-decoration: underline;
}

.post-meta-line {
  font-size: 12px;
  color: #586069;
  margin-bottom: 10px;
}

.post-meta-line a {
  color: #586069;
  text-decoration: none;
  font-weight: 600;
}

.post-meta-line a:hover {
  color: #0366d6;
}

@media (max-width: 768px) {
  .author-thumbnail {
    float: none;
    display: block;
    margin: 0 auto 10px auto;
  }
}

.post-excerpt {
  font-size: 14px;
  color: #24292e;
  line-height: 1.5;
}

.post-excerpt p {
  margin-bottom: 8px;
}

.post-excerpt ul, .post-excerpt ol {
  margin-left: 20px;
  margin-bottom: 8px;
}

.post-excerpt li {
  margin-bottom: 3px;
}

.post-excerpt code {
  background: #f6f8fa;
  padding: 2px 4px;
  border-radius: 3px;
  font-size: 13px;
}

.post-excerpt img {
  float: right;
  width: 35%;
  max-width: 300px;
  margin: 0 0 10px 15px;
  border-radius: 4px;
  cursor: pointer;
  transition: opacity 0.2s;
}

.post-excerpt img:hover {
  opacity: 0.9;
}

@media (max-width: 600px) {
  .post-excerpt img {
    float: none;
    width: 100%;
    max-width: 100%;
    margin: 10px 0;
  }
}

.lightbox {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.9);
  z-index: 1000;
  cursor: pointer;
  align-items: center;
  justify-content: center;
}

.lightbox.active {
  display: flex;
}

.lightbox img {
  max-width: 95%;
  max-height: 95%;
  object-fit: contain;
}

.post-full-content {
  display: none;
  font-size: 14px;
  color: #24292e;
  line-height: 1.5;
  margin-top: 10px;
}

.post-full-content.active {
  display: block;
}

.post-full-content p {
  margin-bottom: 10px;
}

.post-full-content ul, .post-full-content ol {
  margin-left: 20px;
  margin-bottom: 10px;
}

.post-full-content li {
  margin-bottom: 4px;
}

.post-full-content h1, .post-full-content h2, .post-full-content h3 {
  margin-top: 15px;
  margin-bottom: 8px;
}

.post-full-content h1 {
  font-size: 18px;
  font-weight: 600;
}

.post-full-content h2 {
  font-size: 16px;
  font-weight: 600;
}

.post-full-content h3 {
  font-size: 15px;
  font-weight: 600;
}

.post-full-content code {
  background: #f6f8fa;
  padding: 2px 4px;
  border-radius: 3px;
  font-size: 13px;
}

.post-full-content pre {
  background: #f6f8fa;
  padding: 10px;
  border-radius: 4px;
  overflow-x: auto;
  margin-bottom: 10px;
}

.post-full-content pre code {
  background: none;
  padding: 0;
}

.post-full-content blockquote {
  border-left: 3px solid #e1e4e8;
  padding-left: 12px;
  margin: 10px 0;
  color: #586069;
}

.post-full-content img {
  max-width: 100%;
  height: auto;
  margin: 10px 0;
  border-radius: 4px;
}

.read-more {
  display: inline-block;
  color: #0366d6;
  font-size: 11px;
  cursor: pointer;
  text-decoration: none;
  padding: 2px 8px;
  border: 1px solid #e1e4e8;
  border-radius: 3px;
  background: #f6f8fa;
  transition: background 0.2s;
  margin-right: 6px;
  vertical-align: middle;
}

.read-more:hover {
  background: #e1e4e8;
}

.read-more::after {
  content: ' ▼';
  font-size: 9px;
}

.read-more.active::after {
  content: ' ▲';
}

.post-tags {
  margin-top: 8px;
  font-size: 11px;
  clear: both;
  display: inline-block;
}

.post-tags a {
  display: inline-block;
  background: #f1f8ff;
  color: #0366d6;
  padding: 2px 6px;
  border-radius: 3px;
  text-decoration: none;
  margin-right: 4px;
  margin-bottom: 4px;
  vertical-align: middle;
  font-size: 11px;
}

.post-tags a:hover {
  background: #dbedff;
}

.post-tags-and-actions {
  margin-top: 8px;
  display: flex;
  align-items: center;
  clear: both;
}

.pagination {
  margin-top: 30px;
  padding-top: 15px;
  border-top: 1px solid #e1e4e8;
  text-align: center;
  font-size: 13px;
}

.pagination a {
  color: #0366d6;
  text-decoration: none;
  margin: 0 8px;
}

.pagination a:hover {
  text-decoration: underline;
}

.pagination .current {
  color: #24292e;
  font-weight: 600;
}

.link-item {
  margin-bottom: 6px;
  padding: 4px 0;
  border-bottom: 1px solid #f0f0f0;
  display: flex;
  align-items: baseline;
  font-size: 13px;
  line-height: 1.4;
}

.link-item:last-child {
  border-bottom: none;
}

.link-url {
  flex: 0 0 auto;
  margin-right: 8px;
}

.link-url a {
  color: #0366d6;
  text-decoration: none;
  font-weight: 500;
}

.link-url a:hover {
  text-decoration: underline;
}

.link-domain {
  color: #24292e;
  font-weight: 500;
}

.link-path {
  color: #586069;
  font-weight: 400;
}

.link-backlinks {
  flex: 1 1 auto;
  font-size: 11px;
  color: #586069;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.link-backlink {
  display: inline-flex;
  align-items: center;
  gap: 3px;
}

.link-backlink a {
  color: #586069;
  text-decoration: none;
}

.link-backlink a:hover {
  color: #0366d6;
}

.link-backlink-icon {
  color: #959da5;
  font-size: 10px;
}

.author-list {
  list-style: none;
}

.author-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 0;
  border-bottom: 1px solid #e1e4e8;
  transition: background 0.15s;
}

.author-item:hover {
  background: #f6f8fa;
  margin: 0 -8px;
  padding: 12px 8px;
}

.author-item-thumbnail {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
  border: 1px solid #e1e4e8;
}

.author-item-main {
  flex: 1;
  min-width: 0;
}

.author-item-name {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 2px;
}

.author-item-name a {
  color: #24292e;
  text-decoration: none;
}

.author-item-name a:hover {
  color: #0366d6;
}

.author-item-meta {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 13px;
  color: #586069;
  flex-wrap: wrap;
}

.author-item-username {
  color: #586069;
}

.author-item-stat {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  color: #586069;
}

.author-item-links {
  display: flex;
  align-items: center;
  gap: 6px;
}

.author-item-link {
  display: inline-flex;
  align-items: center;
  color: #586069;
  text-decoration: none;
  transition: color 0.2s;
}

.author-item-link:hover {
  color: #0366d6;
}

.author-item-link svg {
  width: 16px;
  height: 16px;
}

.author-header {
  background: #f6f8fa;
  border: 1px solid #e1e4e8;
  border-radius: 6px;
  padding: 24px;
  margin-bottom: 24px;
}

.author-header-main {
  display: flex;
  align-items: start;
  gap: 20px;
  margin-bottom: 20px;
}

.author-header-thumbnail {
  width: 96px;
  height: 96px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid #fff;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
  flex-shrink: 0;
}

.author-header-info {
  flex: 1;
}

.author-header-name {
  font-size: 28px;
  font-weight: 700;
  color: #24292e;
  margin-bottom: 6px;
}

.author-header-username {
  font-size: 16px;
  color: #586069;
  margin-bottom: 12px;
}

.author-header-bio {
  font-size: 14px;
  color: #586069;
  line-height: 1.5;
  margin-bottom: 12px;
}

.author-header-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.author-header-link {
  display: inline-flex;
  align-items: center;
  padding: 6px 12px;
  background: #fff;
  border: 1px solid #e1e4e8;
  border-radius: 4px;
  font-size: 13px;
  color: #586069;
  text-decoration: none;
  transition: all 0.2s;
}

.author-header-link:hover {
  border-color: #0366d6;
  color: #0366d6;
}

.author-header-stats {
  display: flex;
  gap: 24px;
  padding-top: 16px;
  border-top: 1px solid #e1e4e8;
}

.author-header-stat {
  display: flex;
  flex-direction: column;
}

.author-header-stat-value {
  font-size: 24px;
  font-weight: 700;
  color: #0366d6;
}

.author-header-stat-label {
  font-size: 12px;
  color: #586069;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.category-list {
  list-style: none;
}

.category-list li {
  margin-bottom: 12px;
  padding-bottom: 12px;
  border-bottom: 1px solid #e1e4e8;
}

.category-list li:last-child {
  border-bottom: none;
}

.category-list a {
  color: #0366d6;
  text-decoration: none;
  font-size: 15px;
}

.category-list a:hover {
  text-decoration: underline;
}

.count {
  color: #586069;
  font-size: 12px;
  margin-left: 6px;
}

footer {
  margin-top: 40px;
  padding-top: 15px;
  border-top: 1px solid #e1e4e8;
  text-align: center;
  font-size: 11px;
  color: #586069;
}
|}

  let html_escape s =
    let buf = Buffer.create (String.length s) in
    String.iter (function
      | '<' -> Buffer.add_string buf "&lt;"
      | '>' -> Buffer.add_string buf "&gt;"
      | '&' -> Buffer.add_string buf "&amp;"
      | '"' -> Buffer.add_string buf "&quot;"
      | '\'' -> Buffer.add_string buf "&#39;"
      | c -> Buffer.add_char buf c
    ) s;
    Buffer.contents buf

  let format_date date =
    let open Unix in
    let tm = gmtime (Ptime.to_float_s date) in
    let months = [|"January"; "February"; "March"; "April"; "May"; "June";
                   "July"; "August"; "September"; "October"; "November"; "December"|] in
    Printf.sprintf "%s %d, %d" months.(tm.tm_mon) tm.tm_mday (1900 + tm.tm_year)

  let page_template ~title ~nav_current content =
    Printf.sprintf {|<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>%s</title>
  <style>%s</style>
</head>
<body>
  <header>
    <h1><a href="index.html">River Feed</a></h1>
    <nav>
      <a href="index.html"%s>Posts</a>
      <a href="authors/index.html"%s>Authors</a>
      <a href="categories/index.html"%s>Categories</a>
      <a href="links.html"%s>Links</a>
    </nav>
  </header>
  <main>
%s
  </main>
  <footer>
    Generated by River Feed Aggregator
  </footer>
  <div class="lightbox" id="lightbox">
    <img id="lightbox-img" src="" alt="">
  </div>
  <script>
    (function() {
      const lightbox = document.getElementById('lightbox');
      const lightboxImg = document.getElementById('lightbox-img');

      // Add click handler to all images in excerpts and full content
      document.addEventListener('click', function(e) {
        if (e.target.tagName === 'IMG' && (e.target.closest('.post-excerpt') || e.target.closest('.post-full-content'))) {
          e.preventDefault();
          lightboxImg.src = e.target.src;
          lightboxImg.alt = e.target.alt;
          lightbox.classList.add('active');
        }
      });

      // Close lightbox on click
      lightbox.addEventListener('click', function() {
        lightbox.classList.remove('active');
        lightboxImg.src = '';
      });

      // Close on escape key
      document.addEventListener('keydown', function(e) {
        if (e.key === 'Escape' && lightbox.classList.contains('active')) {
          lightbox.classList.remove('active');
          lightboxImg.src = '';
        }
      });

      // Read more toggle
      document.addEventListener('click', function(e) {
        if (e.target.classList.contains('read-more')) {
          e.preventDefault();
          const post = e.target.closest('.post');
          const fullContent = post.querySelector('.post-full-content');
          const excerpt = post.querySelector('.post-excerpt');

          if (fullContent.classList.contains('active')) {
            fullContent.classList.remove('active');
            excerpt.style.display = 'block';
            e.target.textContent = 'Read more';
            e.target.classList.remove('active');
          } else {
            fullContent.classList.add('active');
            excerpt.style.display = 'none';
            e.target.textContent = 'Show less';
            e.target.classList.add('active');
          }
        }
      });
    })();
  </script>
</body>
</html>|}
      (html_escape title)
      css
      (if nav_current = "posts" then " class=\"current\"" else "")
      (if nav_current = "authors" then " class=\"current\"" else "")
      (if nav_current = "categories" then " class=\"current\"" else "")
      (if nav_current = "links" then " class=\"current\"" else "")
      content

  let pagination_html ~current_page ~total_pages ~base_path =
    if total_pages <= 1 then ""
    else
      let prev = if current_page > 1 then
        let prev_page = current_page - 1 in
        let href = if prev_page = 1 then base_path ^ "index.html"
                   else Printf.sprintf "%spage-%d.html" base_path prev_page in
        Printf.sprintf {|<a href="%s">← Previous</a>|} href
      else ""
      in
      let next = if current_page < total_pages then
        Printf.sprintf {|<a href="%spage-%d.html">Next →</a>|} base_path (current_page + 1)
      else ""
      in
      let pages =
        let buf = Buffer.create 256 in
        for i = 1 to total_pages do
          if i = current_page then
            Buffer.add_string buf (Printf.sprintf {| <span class="current">%d</span>|} i)
          else
            let href = if i = 1 then base_path ^ "index.html"
                       else Printf.sprintf "%spage-%d.html" base_path i in
            Buffer.add_string buf (Printf.sprintf {| <a href="%s">%d</a>|} href i)
        done;
        Buffer.contents buf
      in
      Printf.sprintf {|<div class="pagination">%s%s%s</div>|} prev pages next

  let full_content_from_html html_content =
    (* Convert HTML to markdown then to clean HTML using Cmarkit *)
    let markdown = Html_markdown.html_to_markdown html_content in
    let doc = Cmarkit.Doc.of_string markdown in
    Cmarkit_html.of_doc ~safe:true doc

  let post_excerpt_from_html html_content ~max_length =
    (* Convert HTML to markdown for excerpt *)
    let markdown = Html_markdown.html_to_markdown html_content in
    (* Find paragraph break after max_length *)
    let excerpt_md =
      if String.length markdown <= max_length then markdown
      else
        (* Look for double newline (paragraph break) after max_length *)
        let start_search = min max_length (String.length markdown - 1) in
        let rec find_para_break pos =
          if pos >= String.length markdown - 1 then
            String.length markdown
          else if pos < String.length markdown - 1 &&
                  markdown.[pos] = '\n' && markdown.[pos + 1] = '\n' then
            pos
          else
            find_para_break (pos + 1)
        in
        let break_pos = find_para_break start_search in
        let truncated = String.sub markdown 0 break_pos in
        if break_pos < String.length markdown then
          truncated ^ "..."
        else
          truncated
    in
    (* Convert markdown back to HTML using Cmarkit with custom renderer *)
    let doc = Cmarkit.Doc.of_string excerpt_md in

    (* Custom renderer that makes headings smaller and strips images *)
    let excerpt_customizations =
      let block c = function
        | Cmarkit.Block.Heading (h, _) ->
            let level = Cmarkit.Block.Heading.level h in
            let inline = Cmarkit.Block.Heading.inline h in
            (* Render heading as a strong tag with smaller font *)
            let style = match level with
              | 1 -> "font-size: 15px; font-weight: 600;"
              | 2 -> "font-size: 14px; font-weight: 600;"
              | _ -> "font-size: 14px; font-weight: 500;"
            in
            Cmarkit_renderer.Context.string c (Printf.sprintf "<strong style=\"%s\">" style);
            Cmarkit_renderer.Context.inline c inline;
            Cmarkit_renderer.Context.string c "</strong> ";
            true
        | _ -> false
      in
      let inline _c = function
        | Cmarkit.Inline.Image _ ->
            (* Skip images in excerpts *)
            true
        | _ -> false
      in
      Cmarkit_renderer.make ~block ~inline ()
    in

    let renderer = Cmarkit_renderer.compose (Cmarkit_html.renderer ~safe:true ()) excerpt_customizations in
    Cmarkit_renderer.doc_to_string renderer doc

  let render_post_html ~post ~author_username =
    let title = Post.title post in
    let author = Post.author post in
    let date_str = match Post.date post with
      | Some d -> format_date d
      | None -> "No date"
    in
    let link_html = match Post.link post with
      | Some uri ->
          Printf.sprintf {|<a href="%s">%s</a>|}
            (html_escape (Uri.to_string uri))
            (html_escape title)
      | None -> html_escape title
    in
    let excerpt = post_excerpt_from_html (Post.content post) ~max_length:300 in
    let tags_html =
      match Post.tags post with
      | [] -> ""
      | tags ->
          let tag_links = List.map (fun tag ->
            Printf.sprintf {|<a href="../categories/%s.html">%s</a>|}
              (html_escape tag) (html_escape tag)
          ) tags in
          Printf.sprintf {|<div class="post-tags">%s</div>|}
            (String.concat "" tag_links)
    in
    Printf.sprintf {|<article class="post">
  <h2 class="post-title">%s</h2>
  <div class="post-meta">
    By <a href="../authors/%s.html">%s</a> on %s
  </div>
  <div class="post-excerpt">
%s
  </div>
%s
</article>|}
      link_html
      (html_escape author_username)
      (html_escape author)
      date_str
      excerpt
      tags_html

  let render_posts_page ~title ~posts ~current_page ~total_pages ~base_path ~nav_current =
    let posts_html = String.concat "\n" posts in
    let pagination = pagination_html ~current_page ~total_pages ~base_path in
    let content = posts_html ^ "\n" ^ pagination in
    page_template ~title ~nav_current content
end