From 4f9723704999a5981f5166b06953e575591c4dce Mon Sep 17 00:00:00 2001
From: fiatjaf <fiatjaf@gmail.com>
Date: Wed, 18 Jan 2023 11:33:13 -0300
Subject: [PATCH] highlight npub/etc references in the textarea.

---
 Cargo.lock     | 23 ++++++++++++++++
 Cargo.toml     |  1 +
 src/tags.rs    | 75 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/ui/feed.rs | 11 ++++++--
 4 files changed, 108 insertions(+), 2 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 48048e4d..5da60042 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1712,6 +1712,7 @@ dependencies = [
  "image",
  "lazy_static",
  "linkify",
+ "memoize",
  "nostr-types",
  "parking_lot",
  "rand 0.8.5",
@@ -2191,6 +2192,28 @@ dependencies = [
  "autocfg",
 ]
 
+[[package]]
+name = "memoize"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c25d125e4063f313300d87c8f658e5b3d69257095df9a4221c12ba50b0421bff"
+dependencies = [
+ "lazy_static",
+ "memoize-inner",
+]
+
+[[package]]
+name = "memoize-inner"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b8b7d5160e6ffcc59d4c571c38238ec5b7065bc91a5a24f511988dabcddda723"
+dependencies = [
+ "lazy_static",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "mime"
 version = "0.3.16"
diff --git a/Cargo.toml b/Cargo.toml
index 21440a8c..37666ca4 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -25,6 +25,7 @@ http = "0.2"
 image = { version = "0.24", features = [ "png", "jpeg" ] }
 lazy_static = "1.4"
 linkify = "0.9"
+memoize = "0.3"
 nostr-types = { git = "https://github.com/mikedilger/nostr-types" }
 parking_lot = "0.12"
 rand = "0.8"
diff --git a/src/tags.rs b/src/tags.rs
index 53ad9745..6e3b1fb8 100644
--- a/src/tags.rs
+++ b/src/tags.rs
@@ -1,4 +1,9 @@
 use crate::db::DbRelay;
+use eframe::epaint::{
+    text::{LayoutJob, TextFormat},
+    Color32, FontFamily, FontId,
+};
+use memoize::memoize;
 use nostr_types::{Id, PublicKey, PublicKeyHex, Tag};
 
 pub fn keys_from_text(text: &str) -> Vec<(String, PublicKey)> {
@@ -87,6 +92,76 @@ pub async fn add_event_to_tags(existing_tags: &mut Vec<Tag>, added: Id, marker:
     }
 }
 
+enum HighlightType {
+    Nothing,
+    PublicKey,
+    Event,
+}
+
+#[memoize]
+pub fn textarea_highlighter(text: String) -> LayoutJob {
+    let mut job = LayoutJob::default();
+
+    let ids = notes_from_text(&text);
+    let pks = keys_from_text(&text);
+
+    // we will gather indices such that we can split the text in chunks
+    let mut indices: Vec<(usize, HighlightType)> = vec![];
+    for pk in pks {
+        for m in text.match_indices(&pk.0) {
+            indices.push((m.0, HighlightType::Nothing));
+            indices.push((m.0 + pk.0.len(), HighlightType::PublicKey));
+        }
+    }
+    for id in ids {
+        for m in text.match_indices(&id.0) {
+            indices.push((m.0, HighlightType::Nothing));
+            indices.push((m.0 + id.0.len(), HighlightType::Event));
+        }
+    }
+    indices.sort_by_key(|x| x.0);
+    indices.dedup_by_key(|x| x.0);
+
+    // add a breakpoint at the end if it doesn't exist
+    if indices.is_empty() || indices[indices.len() - 1].0 != text.len() {
+        indices.push((text.len(), HighlightType::Nothing));
+    }
+
+    // now we will add each chunk back to the textarea with custom formatting
+    let mut curr = 0;
+    for (index, highlight) in indices {
+        let chunk = &text[curr..index];
+
+        job.append(
+            chunk,
+            0.0,
+            match highlight {
+                HighlightType::Nothing => TextFormat {
+                    font_id: FontId::new(14.0, FontFamily::Proportional),
+                    color: Color32::BLACK,
+                    ..Default::default()
+                },
+                HighlightType::PublicKey => TextFormat {
+                    font_id: FontId::new(16.0, FontFamily::Monospace),
+                    background: Color32::LIGHT_GRAY,
+                    color: Color32::DARK_GREEN,
+                    ..Default::default()
+                },
+                HighlightType::Event => TextFormat {
+                    font_id: FontId::new(16.0, FontFamily::Monospace),
+                    background: Color32::LIGHT_GRAY,
+                    color: Color32::DARK_RED,
+                    ..Default::default()
+                },
+            },
+        );
+
+        curr = index;
+    }
+
+    job
+}
+
 #[cfg(test)]
 mod test {
     use super::*;
diff --git a/src/ui/feed.rs b/src/ui/feed.rs
index 8d407268..ec8bf80b 100644
--- a/src/ui/feed.rs
+++ b/src/ui/feed.rs
@@ -2,7 +2,7 @@ use super::{GossipUi, Page};
 use crate::comms::ToOverlordMessage;
 use crate::feed::FeedKind;
 use crate::globals::{Globals, GLOBALS};
-use crate::tags::keys_from_text;
+use crate::tags::{keys_from_text, textarea_highlighter};
 use crate::ui::widgets::CopyButton;
 use crate::AVATAR_SIZE_F32;
 use eframe::egui;
@@ -185,11 +185,18 @@ fn real_posting_area(app: &mut GossipUi, ctx: &Context, frame: &mut eframe::Fram
         });
 
         // Text area
+        let mut layouter = |ui: &Ui, text: &str, wrap_width: f32| {
+            let mut layout_job = textarea_highlighter(text.to_owned());
+            layout_job.wrap.max_width = wrap_width;
+            ui.fonts().layout_job(layout_job)
+        };
+
         ui.add(
             TextEdit::multiline(&mut app.draft)
                 .hint_text("Type your message here")
                 .desired_width(f32::INFINITY)
-                .lock_focus(true),
+                .lock_focus(true)
+                .layouter(&mut layouter),
         );
     });