generate subpage listings automatically

right now very barebones!

- doesn't sort pages quite correctly
- no search function
- still not sure about the UI design aspects

includes refactor of tree generation code

crates/treehouse/src/tree/attributes.rs

@@ -1,6 +1,6 @@
-use std::collections::HashMap;
-
+use chrono::{DateTime, Utc};
 use serde::{Deserialize, Serialize};
+use ulid::Ulid;
 
 use crate::{state::FileId, vfs::VPathBuf};
 
@@ -18,6 +18,11 @@ pub struct RootAttributes {
     #[serde(default)]
     pub title: String,
 
+    /// Page icon used in indexes.
+    /// This is an emoji name, such as `page` (default).
+    #[serde(default = "default_icon")]
+    pub icon: String,
+
     /// Summary of the generated .html page.
     #[serde(default)]
     pub description: Option<String>,
@@ -36,6 +41,15 @@ pub struct RootAttributes {
     #[serde(default)]
     pub styles: Vec<String>,
 
+    /// Visibility of a page in the parent page's index.
+    #[serde(default)]
+    pub visibility: Visibility,
+
+    /// The page's timestamps. These are automatically populated if a page has at least one branch
+    /// with an ID that includes a timestamp.
+    #[serde(default)]
+    pub timestamps: Option<Timestamps>,
+
     /// When specified, this page will have a corresponding Atom feed under `rss/{feed}.xml`.
     ///
     /// In feeds, top-level branches are expected to have a single heading containing the post title.
@@ -55,6 +69,28 @@ pub struct Picture {
     pub alt: Option<String>,
 }
 
+/// Visibility of a page.
+#[derive(Debug, Default, Clone, PartialEq, Eq, Deserialize, Serialize)]
+pub enum Visibility {
+    #[default]
+    Public,
+    /// Hidden from the parent page's index.
+    Private,
+}
+
+/// Timestamps for a page.
+#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Deserialize, Serialize)]
+pub struct Timestamps {
+    /// When the page was created. By default, this is the timestamp of the least recent branch.
+    pub created: DateTime<Utc>,
+    /// When the page was last updated. By default, this is the timestamp of the most recent branch.
+    pub updated: DateTime<Utc>,
+}
+
+fn default_icon() -> String {
+    String::from("page")
+}
+
 /// Branch attributes.
 #[derive(Debug, Default, Clone, PartialEq, Eq, Deserialize)]
 pub struct Attributes {
@@ -96,16 +132,24 @@ pub struct Attributes {
     #[serde(default)]
     pub cast: String,
 
-    /// List of extra `data` attributes to add to the block.
-    #[serde(default)]
-    pub data: HashMap<String, String>,
-
     /// In feeds, specifies the list of tags to attach to an entry.
     /// This only has an effect on top-level branches.
     #[serde(default)]
     pub tags: Vec<String>,
 }
 
+impl Attributes {
+    /// Parses the timestamp out of the branch's ID.
+    /// Returns `None` if the ID does not contain a timestamp.
+    pub fn timestamp(&self) -> Option<DateTime<Utc>> {
+        Ulid::from_string(&self.id)
+            .ok()
+            .as_ref()
+            .map(Ulid::timestamp_ms)
+            .and_then(|ms| DateTime::from_timestamp_millis(ms as i64))
+    }
+}
+
 /// Controls for block content presentation.
 #[derive(Debug, Default, Clone, PartialEq, Eq, Deserialize)]
 #[serde(rename_all = "snake_case")]