server: render calendar summary before any pre-existing text

server/Cargo.toml

@@ -12,6 +12,7 @@ version.workspace = true
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+html2text = "0.6"
 ammonia = "4.1.0"
 anyhow = "1.0.98"
 askama = { version = "0.14.0", features = ["derive"] }

server/src/email_extract.rs

@@ -328,25 +328,43 @@ pub fn extract_alternative(
             return extract_related(sp, part_addr);
         }
     }
+    let mut ical_summary: Option<String> = None;
     for sp in &m.subparts {
         if sp.ctype.mimetype.as_str() == TEXT_CALENDAR {
             let body = sp.get_body()?;
             let summary = render_ical_summary(&body)?;
-            return Ok(Body::html(summary));
+            ical_summary = Some(summary);
+            break;
         }
     }
     for sp in &m.subparts {
         if sp.ctype.mimetype.as_str() == TEXT_HTML {
             let body = sp.get_body()?;
-            return Ok(Body::html(body));
+            if let Some(ref summary) = ical_summary {
+                // Prepend summary to HTML body
+                let combined = format!("{}<hr>{}", summary, body);
+                return Ok(Body::html(combined));
+            } else {
+                return Ok(Body::html(body));
+            }
         }
     }
     for sp in &m.subparts {
         if sp.ctype.mimetype.as_str() == TEXT_PLAIN {
             let body = sp.get_body()?;
-            return Ok(Body::text(body));
+            if let Some(ref summary) = ical_summary {
+                // Prepend summary to plain text body (strip HTML tags)
+                let summary_text = html2text::from_read(summary.as_bytes(), 80);
+                let combined = format!("{}\n\n{}", summary_text.trim(), body);
+                return Ok(Body::text(combined));
+            } else {
+                return Ok(Body::text(body));
+            }
         }
     }
+    if let Some(summary) = ical_summary {
+        return Ok(Body::html(summary));
+    }
     Err(ServerError::StringError(format!(
         "extract_alternative failed to find suitable subpart, searched: {:?}",
         handled_types