feat(rss): implement RSS feed adapter and integrate with application state

crates/adapters/rss/Cargo.toml

@@ -4,3 +4,7 @@ version = "0.1.0"
 edition = "2024"
 
 [dependencies]
+rss-feed = { package = "rss", version = "2" }
+chrono = { workspace = true }
+domain = { workspace = true }
+application = { workspace = true }

crates/adapters/rss/src/lib.rs

@@ -1,14 +1,58 @@
-pub fn add(left: u64, right: u64) -> u64 {
-    left + right
+use application::ports::RssFeedRenderer;
+use domain::models::DiaryEntry;
+use rss_feed::{ChannelBuilder, GuidBuilder, ItemBuilder};
+
+pub struct RssAdapter {
+    feed_title: String,
+    feed_link: String,
 }
 
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
+impl RssAdapter {
+    pub fn new(feed_title: String, feed_link: String) -> Self {
+        Self { feed_title, feed_link }
+    }
+}
+
+impl RssFeedRenderer for RssAdapter {
+    fn render_feed(&self, entries: &[DiaryEntry]) -> Result<String, String> {
+        let items = entries
+            .iter()
+            .map(|e| {
+                let title = format!(
+                    "{} ({})",
+                    e.movie().title().value(),
+                    e.movie().release_year().value()
+                );
+                let description = match e.review().comment() {
+                    Some(c) => format!("{}/5 — {}", e.review().rating().value(), c.value()),
+                    None => format!("{}/5", e.review().rating().value()),
+                };
+                let pub_date = e
+                    .review()
+                    .watched_at()
+                    .and_utc()
+                    .format("%a, %d %b %Y %H:%M:%S +0000")
+                    .to_string();
+                let guid = GuidBuilder::default()
+                    .value(e.review().id().value().to_string())
+                    .permalink(false)
+                    .build();
+                ItemBuilder::default()
+                    .title(Some(title))
+                    .description(Some(description))
+                    .pub_date(Some(pub_date))
+                    .guid(Some(guid))
+                    .build()
+            })
+            .collect::<Vec<_>>();
+
+        let channel = ChannelBuilder::default()
+            .title(self.feed_title.clone())
+            .link(self.feed_link.clone())
+            .description(self.feed_title.clone())
+            .items(items)
+            .build();
+
+        Ok(channel.to_string())
     }
 }