widgets: begin organizing ui components into widgets

egui widgets are nice because there are many helper methods on the
egui::Ui struct for adding widgets to the screen in various ways. For
example, add_sized which designates an area to paint a widget. This is
useful in the note_contents case, as it allows us to reserve
available_space-20.0 pixels of the available area, saving 20.0 pixels
for a side-actionbar popout.

I'm not sure I'll use the side actionbar yet, but I've been
experimenting with that as an option to save vertical space in the
timeline.

I still need to make the side actionbar into a widget as well. It
currently uses the CollapsingHeader widget, which is designed for
expanding elements vertically. We may need to make our own widget for
animating an horizontal expansion if we want to achieve a similar effect
for the side actionbar.

src/widgets/note/contents.rs

@@ -0,0 +1,121 @@
+use crate::{colors, Damus};
+use egui::{Hyperlink, Image, RichText};
+use nostrdb::{BlockType, Mention, Note, NoteKey, Transaction};
+use tracing::warn;
+
+pub struct NoteContents<'a> {
+    damus: &'a mut Damus,
+    txn: &'a Transaction,
+    note: &'a Note<'a>,
+    note_key: NoteKey,
+}
+
+impl<'a> NoteContents<'a> {
+    pub fn new(
+        damus: &'a mut Damus,
+        txn: &'a Transaction,
+        note: &'a Note,
+        note_key: NoteKey,
+    ) -> Self {
+        NoteContents {
+            damus,
+            txn,
+            note,
+            note_key,
+        }
+    }
+}
+
+impl egui::Widget for NoteContents<'_> {
+    fn ui(self, ui: &mut egui::Ui) -> egui::Response {
+        render_note_contents(ui, self.damus, self.txn, self.note, self.note_key).response
+    }
+}
+
+fn render_note_contents(
+    ui: &mut egui::Ui,
+    damus: &mut Damus,
+    txn: &Transaction,
+    note: &Note,
+    note_key: NoteKey,
+) -> egui::InnerResponse<()> {
+    #[cfg(feature = "profiling")]
+    puffin::profile_function!();
+
+    let mut images: Vec<String> = vec![];
+
+    let resp = ui.horizontal_wrapped(|ui| {
+        let blocks = if let Ok(blocks) = damus.ndb.get_blocks_by_key(txn, note_key) {
+            blocks
+        } else {
+            warn!("missing note content blocks? '{}'", note.content());
+            ui.weak(note.content());
+            return;
+        };
+
+        ui.spacing_mut().item_spacing.x = 0.0;
+
+        for block in blocks.iter(note) {
+            match block.blocktype() {
+                BlockType::MentionBech32 => {
+                    ui.colored_label(colors::PURPLE, "@");
+                    match block.as_mention().unwrap() {
+                        Mention::Pubkey(npub) => {
+                            let profile = damus.ndb.get_profile_by_pubkey(txn, npub.pubkey()).ok();
+                            if let Some(name) = profile
+                                .as_ref()
+                                .and_then(|p| crate::profile::get_profile_name(p))
+                            {
+                                ui.colored_label(colors::PURPLE, name);
+                            } else {
+                                ui.colored_label(colors::PURPLE, "nostrich");
+                            }
+                        }
+                        _ => {
+                            ui.colored_label(colors::PURPLE, block.as_str());
+                        }
+                    }
+                }
+
+                BlockType::Hashtag => {
+                    ui.colored_label(colors::PURPLE, "#");
+                    ui.colored_label(colors::PURPLE, block.as_str());
+                }
+
+                BlockType::Url => {
+                    /*
+                    let url = block.as_str().to_lowercase();
+                    if url.ends_with("png") || url.ends_with("jpg") {
+                        images.push(url);
+                    } else {
+                    */
+                    ui.add(Hyperlink::from_label_and_url(
+                        RichText::new(block.as_str()).color(colors::PURPLE),
+                        block.as_str(),
+                    ));
+                    //}
+                }
+
+                BlockType::Text => {
+                    ui.label(block.as_str());
+                }
+
+                _ => {
+                    ui.colored_label(colors::PURPLE, block.as_str());
+                }
+            }
+        }
+    });
+
+    for image in images {
+        let img_resp = ui.add(Image::new(image.clone()));
+        img_resp.context_menu(|ui| {
+            if ui.button("Copy Link").clicked() {
+                ui.ctx().copy_text(image);
+                ui.close_menu();
+            }
+        });
+    }
+
+    resp
+}

src/widgets/note/mod.rs

@@ -0,0 +1,3 @@
+pub mod contents;
+
+pub use contents::NoteContents;