Add text to _changes explaining the query. Add links to variants of the query

src/resources/changes_resource.rs

@@ -234,11 +234,57 @@ impl Resource for ChangesResource {
         #[derive(BartDisplay)]
         #[template="templates/changes.html"]
         struct Template<'a> {
+            resource: &'a ChangesResource,
+
             newer: Option<NavLinks>,
             older: Option<NavLinks>,
             changes: &'a [Row<'a>],
         }
 
+        impl<'a> Template<'a> {
+            fn subject_clause(&self) -> String {
+                match self.resource.article_id {
+                    Some(x) => format!(" <a href=\"_by_id/{}\">this article</a>", x),
+                    None => format!(" the wiki"),
+                }
+            }
+
+            fn author_clause(&self) -> String {
+                #[derive(BartDisplay)]
+                #[template_string=" by <a href=\"{{link}}\">{{author}}</a>"]
+                struct AuthorClause<'a> {
+                    link: &'a str,
+                    author: &'a str,
+                }
+
+                match self.resource.author {
+                    Some(ref x) => AuthorClause {
+                        link: &self.resource.query_args()
+                            .author(Some(x.clone()))
+                            .into_link(),
+                        author: &x
+                    }.to_string(),
+                    None => "".to_owned(),
+                }
+            }
+
+            fn all_articles_link(&self) -> Option<String> {
+                self.resource.article_id.map(|_| {
+                    self.resource.query_args()
+                        .article_id(None)
+                        .into_link()
+                })
+            }
+
+            fn all_authors_link(&self) -> Option<String> {
+                self.resource.author.as_ref().map(|_| {
+                    self.resource.query_args()
+                        .author(None)
+                        .into_link()
+                })
+            }
+        }
+
         let (before, article_id, author, limit) =
             (self.before.clone(), self.article_id.clone(), self.author.clone(), self.limit);
         let data = self.state.query_article_revision_stubs(move |query| {
@@ -308,6 +354,7 @@ impl Resource for ChangesResource {
                         base: None, // Hmm, should perhaps accept `base` as argument
                         title: "Changes",
                         body: &Template {
+                            resource: &self,
                             newer,
                             older,
                             changes

templates/changes.html

@@ -4,6 +4,16 @@
 </header>
 
 <article>
+<p>
+    These are the {{^newer}}most recent{{/newer}} changes that have been
+    made to{{{subject_clause()}}}{{{author_clause()}}}.
+</p>
+
+<nav><ul class="dense">
+    {{#all_articles_link()}}<li><a href="{{.}}">All articles</a></li>{{/all_articles_link()}}
+    {{#all_authors_link()}}<li><a href="{{.}}">All authors</a></li>{{/all_authors_link()}}
+</ul></nav>
+
 {{#newer}}<nav><ul class="dense"
     ><li><a rel="prev" href="{{.more}}">More recent changes</a></li
     ><li><a rel="first" href="{{.end}}">Most recent changes</a></li
@@ -25,12 +35,13 @@
     {{/changes}}
 </table>
 {{^changes?}}
-<p>No hits</p>
+<p>There are no changes to show.</p>
 {{/changes}}
 {{#older}}<nav><ul class="dense"
     ><li><a rel="next" href="{{.more}}">Older changes</a></li
     ><li><a rel="last" href="{{.end}}">First changes</a></li
 ></ul></nav>{{/older}}
+{{#changes?}}{{^older}}<p>There are no older changes.</p>{{/older}}{{/changes}}
 </article>
 </div>