From 3b63bbdfde35c2a1d5bad739eaf68ff632aecf1a Mon Sep 17 00:00:00 2001
From: Tom Alexander <tom@fizz.buzz>
Date: Sat, 23 Dec 2023 21:29:59 -0500
Subject: [PATCH] Add support for subpaths.

---
 src/intermediate/regular_link.rs | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/src/intermediate/regular_link.rs b/src/intermediate/regular_link.rs
index dfed5c3..50a52a7 100644
--- a/src/intermediate/regular_link.rs
+++ b/src/intermediate/regular_link.rs
@@ -43,7 +43,10 @@ intermediate!(
 #[derive(Debug, Clone)]
 pub(crate) enum LinkTarget {
     Raw(String),
-    Post { post_id: Option<String> },
+    Post {
+        post_id: Option<String>,
+        subpath: String,
+    },
 }
 
 impl LinkTarget {
@@ -59,7 +62,18 @@ impl LinkTarget {
             match parsed.scheme() {
                 "post" => {
                     let post_id = parsed.host_str().map(str::to_owned);
-                    Ok(LinkTarget::Post { post_id })
+                    let subpath = {
+                        let subpath = parsed.path();
+                        if subpath.starts_with('/') {
+                            &subpath[1..]
+                        } else {
+                            subpath
+                        }
+                    };
+                    Ok(LinkTarget::Post {
+                        post_id,
+                        subpath: subpath.to_owned(),
+                    })
                 }
                 _ => Ok(LinkTarget::Raw(input.to_owned())),
             }
@@ -73,15 +87,19 @@ impl LinkTarget {
     ) -> Result<Option<String>, CustomError> {
         match self {
             LinkTarget::Raw(raw_link) => Ok(Some(raw_link.clone())),
-            LinkTarget::Post { post_id } => {
+            LinkTarget::Post { post_id, subpath } => {
                 let path = post_id
                     .as_ref()
                     .map(|post_id| {
+                        let path_to_post = render_context
+                            .config
+                            .get_relative_path_to_post(post_id)
+                            .join(subpath);
                         get_web_path(
                             render_context.config,
                             render_context.output_root_directory,
                             render_context.output_file,
-                            render_context.config.get_relative_path_to_post(post_id),
+                            path_to_post,
                         )
                     })
                     .map_or(Ok(None), |r| r.map(Some))?;