From 17941d90be80f71282af53701b6b9f0eb5bbec9e Mon Sep 17 00:00:00 2001
From: Leonora Tindall <nora@nora.codes>
Date: Mon, 31 Oct 2022 21:41:07 -0500
Subject: [PATCH] Links and correct sorting

---
 Cargo.lock         |  1 +
 Cargo.toml         |  1 +
 README.md          |  2 +-
 src/syndication.rs | 28 ++++++++++++++++++++++++----
 4 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index a8c0f62..dd56435 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -295,6 +295,7 @@ checksum = "5827cebf4670468b8772dd191856768aedcb1b0278a04f989f7766351917b9dc"
 name = "corobel"
 version = "0.1.0"
 dependencies = [
+ "atom_syndication",
  "chrono",
  "clap",
  "eggbug",
diff --git a/Cargo.toml b/Cargo.toml
index b6eb599..0c51c74 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,3 +17,4 @@ once_cell = "1.16.0"
 chrono = { version = "0.4.22", features = [ "serde" ] }
 rss = { version = "2.0.1", features = [ "builders", "atom", "chrono" ] }
 pulldown-cmark = "0.9.2"
+atom_syndication = "0.11.0"
diff --git a/README.md b/README.md
index c2ae58d..3b595d7 100644
--- a/README.md
+++ b/README.md
@@ -17,7 +17,7 @@ ports to use for development and deployment.
 - [x] RSS feeds for projects
 - [x] Index page explaining what's going on
 - [ ] RSS feeds for tags
-- [ ] Atom Extension pagination support
+- [x] Atom Extension pagination support
 - [ ] Read More support
 - [ ] Dublin Core support
 - [ ] Media Envelope support
diff --git a/src/syndication.rs b/src/syndication.rs
index c37aaf9..c35a9af 100644
--- a/src/syndication.rs
+++ b/src/syndication.rs
@@ -2,13 +2,20 @@ use crate::cohost_account::CohostAccount;
 use crate::cohost_posts::*;
 use crate::ARGS;
 use rss::Channel;
+use rss::extension::atom::{AtomExtensionBuilder, Link};
+use  atom_syndication::LinkBuilder;
+
+fn rel_link_for(rel: &str, project_name: &str, page_number: u64) -> Link {
+    LinkBuilder::default().rel(rel).href(format!("https://{}{}{}/feed.rss?page={}", &ARGS.domain, &ARGS.base_url, project_name.clone(), page_number)).build()
+}
 
 pub fn channel_for_posts_page(
     project_name: impl AsRef<str>,
     page_number: u64,
     project: CohostAccount,
-    page: CohostPostsPage,
+    mut page: CohostPostsPage,
 ) -> Channel {
+    let project_name = project_name.as_ref().clone();
     let mut builder = rss::ChannelBuilder::default();
     builder
         .title(format!("{} Cohost Posts", project.display_name))
@@ -20,12 +27,25 @@ pub fn channel_for_posts_page(
         )))
         .link(format!(
             "https://cohost.org/{}?page={}",
-            project_name.as_ref(),
+            project_name,
             page_number
         ));
 
-    let mut items = Vec::with_capacity(page.number_items);
+    let mut atom = AtomExtensionBuilder::default();
+    let mut links = vec![rel_link_for("self", project_name, page_number), rel_link_for("first", project_name, 0)];
+    if page_number > 0 {
+        links.push(rel_link_for("prev", project_name, page_number - 1));
+    }
+    if page.number_items > 0 {
+        // Cohost API is wrong about the pagination so we can only guess. If there are posts, there might be more posts.
+        links.push(rel_link_for("next", project_name, page_number + 1));
+    }
+    atom.links(links);
 
+    builder.atom_ext(Some(atom.build()));
+
+    page.items.sort_by_key(|item| item.published_at);
+    let mut items = Vec::with_capacity(page.number_items);
     for item in page.items {
         let mut item_builder = rss::ItemBuilder::default();
         let mut categories: Vec<rss::Category> = Vec::with_capacity(item.tags.len());
@@ -47,7 +67,7 @@ pub fn channel_for_posts_page(
             .pub_date(item.published_at.to_rfc2822())
             .source(Some(rss::Source {
                 title: Some(format!("{} Cohost Posts", project.display_name)),
-                url: format!("https://{}/feed/{}.rss", ARGS.domain, project_name.as_ref()),
+                url: format!("https://{}/feed/{}.rss", ARGS.domain, project_name),
             }));
 
         let mut body_text = String::new();