From 2d96f009c00a226d295d16dc796b1e2e1fcebc53 Mon Sep 17 00:00:00 2001
From: Yuki Kishimoto <yukikishimoto@protonmail.com>
Date: Thu, 14 Mar 2024 11:14:50 +0100
Subject: [PATCH] nostr: add `EventBuilder::text_note_reply`

Closes https://github.com/rust-nostr/nostr/issues/333
---
 bindings/nostr-ffi/src/event/builder.rs | 22 +++++++
 bindings/nostr-js/src/event/builder.rs  | 22 +++++++
 crates/nostr/src/event/builder.rs       | 76 +++++++++++++++++++++++++
 3 files changed, 120 insertions(+)

diff --git a/bindings/nostr-ffi/src/event/builder.rs b/bindings/nostr-ffi/src/event/builder.rs
index fb9f434a9..cf19e7110 100644
--- a/bindings/nostr-ffi/src/event/builder.rs
+++ b/bindings/nostr-ffi/src/event/builder.rs
@@ -109,6 +109,28 @@ impl EventBuilder {
         })
     }
 
+    /// Text note reply
+    ///
+    /// If no `root` is passed, the `rely_to` will be used for root `e` tag.
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/10.md>
+    #[uniffi::constructor]
+    pub fn text_note_reply(
+        content: String,
+        reply_to: &Event,
+        root: Option<Arc<Event>>,
+        relay_url: Option<String>,
+    ) -> Self {
+        Self {
+            inner: nostr::EventBuilder::text_note_reply(
+                content,
+                reply_to.deref(),
+                root.as_ref().map(|e| e.as_ref().deref()),
+                relay_url.map(UncheckedUrl::from),
+            ),
+        }
+    }
+
     #[uniffi::constructor]
     pub fn long_form_text_note(content: &str, tags: &[Arc<Tag>]) -> Result<Self> {
         let tags = tags.iter().map(|t| t.as_ref().deref().clone());
diff --git a/bindings/nostr-js/src/event/builder.rs b/bindings/nostr-js/src/event/builder.rs
index 026a1c384..008ba8006 100644
--- a/bindings/nostr-js/src/event/builder.rs
+++ b/bindings/nostr-js/src/event/builder.rs
@@ -112,6 +112,28 @@ impl JsEventBuilder {
         }
     }
 
+    /// Text note reply
+    ///
+    /// If no `root` is passed, the `rely_to` will be used for root `e` tag.
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/10.md>
+    #[wasm_bindgen(js_name = textNoteReply)]
+    pub fn text_note_reply(
+        content: &str,
+        reply_to: &JsEvent,
+        root: Option<JsEvent>,
+        relay_url: Option<String>,
+    ) -> Self {
+        Self {
+            builder: EventBuilder::text_note_reply(
+                content,
+                reply_to.deref(),
+                root.as_deref(),
+                relay_url.map(UncheckedUrl::from),
+            ),
+        }
+    }
+
     #[wasm_bindgen(js_name = longFormTextNote)]
     pub fn long_form_text_note(content: &str, tags: Vec<JsTag>) -> Self {
         Self {
diff --git a/crates/nostr/src/event/builder.rs b/crates/nostr/src/event/builder.rs
index 5337a907a..bbb3de37b 100644
--- a/crates/nostr/src/event/builder.rs
+++ b/crates/nostr/src/event/builder.rs
@@ -396,6 +396,82 @@ impl EventBuilder {
         Self::new(Kind::TextNote, content, tags)
     }
 
+    /// Text note reply
+    ///
+    /// If no `root` is passed, the `rely_to` will be used for root `e` tag.
+    ///
+    /// <https://github.com/nostr-protocol/nips/blob/master/10.md>
+    pub fn text_note_reply<S>(
+        content: S,
+        reply_to: &Event,
+        root: Option<&Event>,
+        relay_url: Option<UncheckedUrl>,
+    ) -> Self
+    where
+        S: Into<String>,
+    {
+        let mut tags: Vec<Tag> = Vec::new();
+
+        // Add `e` and `p` tag of **root** event
+        match root {
+            Some(root) => {
+                // ID and author
+                tags.push(Tag::Event {
+                    event_id: root.id(),
+                    relay_url: relay_url.clone(),
+                    marker: Some(Marker::Root),
+                });
+                tags.push(Tag::public_key(root.author()));
+
+                // Add others `p` tags
+                tags.extend(
+                    root.iter_tags()
+                        .filter(|t| {
+                            t.kind()
+                                == TagKind::SingleLetter(SingleLetterTag {
+                                    character: Alphabet::P,
+                                    uppercase: false,
+                                })
+                        })
+                        .cloned(),
+                );
+            }
+            None => {
+                // No root event is passed, use `reply_to` event ID for `root` marker
+                tags.push(Tag::Event {
+                    event_id: reply_to.id(),
+                    relay_url: relay_url.clone(),
+                    marker: Some(Marker::Root),
+                });
+            }
+        }
+
+        // Add `e` and `p` tag of event author
+        tags.push(Tag::Event {
+            event_id: reply_to.id(),
+            relay_url,
+            marker: Some(Marker::Reply),
+        });
+        tags.push(Tag::public_key(reply_to.author()));
+
+        // Add others `p` tags of reply_to event
+        tags.extend(
+            reply_to
+                .iter_tags()
+                .filter(|t| {
+                    t.kind()
+                        == TagKind::SingleLetter(SingleLetterTag {
+                            character: Alphabet::P,
+                            uppercase: false,
+                        })
+                })
+                .cloned(),
+        );
+
+        // Compose event
+        Self::new(Kind::TextNote, content, tags)
+    }
+
     /// Long-form text note (generally referred to as "articles" or "blog posts").
     ///
     /// <https://github.com/nostr-protocol/nips/blob/master/23.md>