refactor(kanban): compose page with hemplate

Replace board page placeholder string replacement for options/board content with a hemplate page view and partial-rendered options. Cover page structure with DOM-aware scraper assertions.

req: html_safety/002

req: view/001

req: test/005

examples/kanban/src/main.rs

@@ -17,11 +17,11 @@ const COLUMNS: [(&str, &str); 3] = [("backlog", "Backlog"), ("doing", "Doing"),
 
 #[derive(Default)]
 struct AppState {
-    board: Mutex<Board>,
+    board: Mutex<BoardState>,
 }
 
 #[derive(Default, Clone)]
-struct Board {
+struct BoardState {
     next_id: u64,
     cards: Vec<Card>,
 }
@@ -33,6 +33,25 @@ struct Card {
     column: usize,
 }
 
+#[derive(Hemplate)]
+struct Board {
+    options: SafeHtml,
+    board: SafeHtml,
+}
+
+#[derive(Hemplate)]
+#[hemplate = "partials"]
+struct ColumnOptions {
+    options: Vec<ColumnOption>,
+}
+
+#[derive(Hemplate)]
+#[hemplate = "partials"]
+struct ColumnOption {
+    id: &'static str,
+    title: &'static str,
+}
+
 #[derive(Hemplate)]
 #[hemplate = "partials"]
 struct Presence {
@@ -42,7 +61,7 @@ struct Presence {
 #[tokio::main]
 async fn main() {
     let state = Arc::new(AppState {
-        board: Mutex::new(Board {
+        board: Mutex::new(BoardState {
             next_id: 4,
             cards: vec![
                 Card { id: 1, title: "Write requirements".into(), column: 0 },
@@ -153,7 +172,7 @@ fn registry(state: Arc<AppState>) -> HandlerRegistry {
         })
 }
 
-fn board_effects(board: &Board, notice: &'static str) -> impl IntoEffect {
+fn board_effects(board: &BoardState, notice: &'static str) -> impl IntoEffect {
     (
         ui::board::slots::board.html(SafeHtml::trusted(render_board(board))),
         ui::board::slots::notice.text(notice),
@@ -161,7 +180,7 @@ fn board_effects(board: &Board, notice: &'static str) -> impl IntoEffect {
     )
 }
 
-fn update_card(board: &mut Board, card_id: Option<&str>, update: impl FnOnce(&mut Card)) -> bool {
+fn update_card(board: &mut BoardState, card_id: Option<&str>, update: impl FnOnce(&mut Card)) -> bool {
     let Some(id) = card_id.and_then(|id| id.parse::<u64>().ok()) else {
         return false;
     };
@@ -180,10 +199,12 @@ fn parse_column(value: Option<&str>) -> usize {
         .unwrap_or(0)
 }
 
-fn page_html(board: &Board) -> String {
-    ui::board::lower_html(include_str!("../templates/board.heml"))
-        .replace("__OPTIONS__", &render_options())
-        .replace("__BOARD__", &render_board(board))
+fn page_html(board: &BoardState) -> String {
+    // req: html_safety/002 req: view/001
+    ui::board::lower_html(render_template(&Board {
+        options: render_options(),
+        board: SafeHtml::trusted(render_board(board)),
+    }))
 }
 
 fn shell(body: String) -> String {
@@ -213,15 +234,17 @@ fn shell(body: String) -> String {
     )
 }
 
-fn render_options() -> String {
-    COLUMNS
-        .iter()
-        .map(|(id, title)| format!(r#"<option value="{}">{}</option>"#, escape_html(id), escape_html(title)))
-        .collect::<Vec<_>>()
-        .join("")
+fn render_options() -> SafeHtml {
+    // req: html_safety/002 req: view/001
+    render_html(&ColumnOptions {
+        options: COLUMNS
+            .iter()
+            .map(|(id, title)| ColumnOption { id, title })
+            .collect(),
+    })
 }
 
-fn render_board(board: &Board) -> String {
+fn render_board(board: &BoardState) -> String {
     let mut out = String::from("<div class=\"columns\">");
     for (idx, (_, title)) in COLUMNS.iter().enumerate() {
         out.push_str(&format!(r#"<section class="column"><h2>{}</h2>"#, escape_html(title)));
@@ -260,7 +283,11 @@ fn render_presence(count: u64) -> SafeHtml {
 }
 
 fn render_html(template: &impl Hemplate) -> SafeHtml {
-    SafeHtml::trusted(template.render().expect("kanban hemplate partial renders"))
+    SafeHtml::trusted(render_template(template))
+}
+
+fn render_template(template: &impl Hemplate) -> String {
+    template.render().expect("kanban hemplate view renders")
 }
 
 fn escape_html(value: &str) -> String {
@@ -281,6 +308,20 @@ mod tests {
         Selector::parse(value).expect("test selector parses")
     }
 
+    // req: html_safety/002 req: view/001 req: test/005
+    #[test]
+    fn kanban_page_is_composed_by_a_hemplate_view() {
+        let html = page_html(&BoardState::default());
+        assert!(!html.contains("__OPTIONS__"));
+        assert!(!html.contains("__BOARD__"));
+
+        let document = Html::parse_fragment(&html);
+        assert_eq!(document.select(&selector("section[data-slhx-root=\"kanban\"]")).count(), 1);
+        assert_eq!(document.select(&selector("select[name=\"column\"] > option")).count(), 3);
+        assert_eq!(document.select(&selector("[data-sid]")).count(), 3);
+        assert_eq!(document.select(&selector("[data-hid]")).count(), 4);
+    }
+
     // req: html_safety/002 req: view/001 req: test/005
     #[test]
     fn presence_payload_is_rendered_by_a_hemplate_view() {