From 8adc9a0eb6a05f11bfad47948dd90fd7193dccd1 Mon Sep 17 00:00:00 2001
From: Adam <13720823+Frinksy@users.noreply.github.com>
Date: Mon, 10 May 2021 09:06:40 +0100
Subject: [PATCH] events: Add helpers to construct the fallback for rich
 replies

---
 crates/ruma-events/Cargo.toml          |   1 +
 crates/ruma-events/src/room/message.rs | 318 +++++++++++++++++++++++++
 2 files changed, 319 insertions(+)

diff --git a/crates/ruma-events/Cargo.toml b/crates/ruma-events/Cargo.toml
index 2c78efd6..f3789cff 100644
--- a/crates/ruma-events/Cargo.toml
+++ b/crates/ruma-events/Cargo.toml
@@ -13,6 +13,7 @@ edition = "2018"
 
 [dependencies]
 criterion = { version = "0.3.3", optional = true }
+indoc = "1.0"
 js_int = { version = "0.2.0", features = ["serde"] }
 ruma-common = { version = "0.5.0", path = "../ruma-common" }
 ruma-events-macros = { version = "=0.22.0-alpha.3", path = "../ruma-events-macros" }
diff --git a/crates/ruma-events/src/room/message.rs b/crates/ruma-events/src/room/message.rs
index 24f9634a..f1cd263e 100644
--- a/crates/ruma-events/src/room/message.rs
+++ b/crates/ruma-events/src/room/message.rs
@@ -2,6 +2,7 @@
 
 use std::borrow::Cow;
 
+use indoc::formatdoc;
 use js_int::UInt;
 use ruma_events_macros::MessageEventContent;
 use ruma_identifiers::MxcUri;
@@ -85,6 +86,73 @@ impl MessageEventContent {
     pub fn notice_html(body: impl Into<String>, html_body: impl Into<String>) -> Self {
         Self::new(MessageType::Notice(NoticeMessageEventContent::html(body, html_body)))
     }
+
+    /// Creates a plain text reply to a message.
+    pub fn text_reply_plain(reply: impl Into<String>, original_message: &MessageEvent) -> Self {
+        let quoted = get_plain_quote_fallback(original_message);
+
+        let body = format!("{}\n\n{}", quoted, reply.into());
+
+        Self {
+            relates_to: Some(Relation::Reply {
+                in_reply_to: InReplyTo { event_id: original_message.event_id.clone() },
+            }),
+            ..Self::text_plain(body)
+        }
+    }
+
+    /// Creates a html text reply to a message.
+    pub fn text_reply_html(
+        reply: impl Into<String>,
+        html_reply: impl Into<String>,
+        original_message: &MessageEvent,
+    ) -> Self {
+        let quoted = get_plain_quote_fallback(original_message);
+        let quoted_html = get_html_quote_fallback(original_message);
+
+        let body = format!("{}\n\n{}", quoted, reply.into());
+        let html_body = format!("{}\n\n{}", quoted_html, html_reply.into());
+
+        Self {
+            relates_to: Some(Relation::Reply {
+                in_reply_to: InReplyTo { event_id: original_message.event_id.clone() },
+            }),
+            ..Self::text_html(body, html_body)
+        }
+    }
+
+    /// Creates a plain text notice reply to a message.
+    pub fn notice_reply_plain(reply: impl Into<String>, original_message: &MessageEvent) -> Self {
+        let quoted = get_plain_quote_fallback(original_message);
+
+        let body = format!("{}\n\n{}", quoted, reply.into());
+        Self {
+            relates_to: Some(Relation::Reply {
+                in_reply_to: InReplyTo { event_id: original_message.event_id.clone() },
+            }),
+            ..Self::notice_plain(body)
+        }
+    }
+
+    /// Creates a html text notice reply to a message.
+    pub fn notice_reply_html(
+        reply: impl Into<String>,
+        html_reply: impl Into<String>,
+        original_message: &MessageEvent,
+    ) -> Self {
+        let quoted = get_plain_quote_fallback(original_message);
+        let quoted_html = get_html_quote_fallback(original_message);
+
+        let body = format!("{}\n\n{}", quoted, reply.into());
+        let html_body = format!("{}\n\n{}", quoted_html, html_reply.into());
+
+        Self {
+            relates_to: Some(Relation::Reply {
+                in_reply_to: InReplyTo { event_id: original_message.event_id.clone() },
+            }),
+            ..Self::notice_html(body, html_body)
+        }
+    }
 }
 
 /// The content that is specific to each message type variant.
@@ -690,3 +758,253 @@ pub struct CustomEventContent {
     #[serde(flatten)]
     pub data: JsonObject,
 }
+
+fn get_plain_quote_fallback(original_message: &MessageEvent) -> String {
+    match &original_message.content.msgtype {
+        MessageType::Audio(_) => {
+            format!("> <{:?}> sent an audio file.", original_message.sender)
+        }
+        MessageType::Emote(content) => {
+            format!("> * <{:?}> {}", original_message.sender, content.body)
+        }
+        MessageType::File(_) => {
+            format!("> <{:?}> sent a file.", original_message.sender)
+        }
+        MessageType::Image(_) => {
+            format!("> <{:?}> sent an image.", original_message.sender)
+        }
+        MessageType::Location(content) => {
+            format!("> <{:?}> {}", original_message.sender, content.body)
+        }
+        MessageType::Notice(content) => {
+            format!("> <{:?}> {}", original_message.sender, content.body)
+        }
+        MessageType::ServerNotice(content) => {
+            format!("> <{:?}> {}", original_message.sender, content.body)
+        }
+        MessageType::Text(content) => {
+            format!("> <{:?}> {}", original_message.sender, content.body)
+        }
+        MessageType::Video(_) => {
+            format!("> <{:?}> sent a video.", original_message.sender)
+        }
+        MessageType::_Custom(content) => {
+            format!(
+                "> <{:?}> {}",
+                original_message.sender,
+                content.data["body"].as_str().unwrap_or(""),
+            )
+        }
+        #[cfg(feature = "unstable-pre-spec")]
+        MessageType::VerificationRequest(content) => {
+            format!("> <{:?}> {}", original_message.sender, content.body)
+        }
+    }
+}
+
+fn get_html_quote_fallback(original_message: &MessageEvent) -> String {
+    match &original_message.content.msgtype {
+        MessageType::Audio(_) => {
+            formatdoc!(
+                "
+                <mx-reply>
+                    <blockquote>
+                        <a href=\"https://matrix.to/#/{room_id}/{event_id}\">In reply to</a>
+                        <a href=\"https://matrix.to/#/{sender}\">{sender}</a>
+                        <br />
+                        sent an audio file.
+                    </blockquote>
+                </mx-reply>
+                ",
+                room_id = original_message.room_id,
+                event_id = original_message.event_id,
+                sender = original_message.sender,
+            )
+        }
+        MessageType::Emote(content) => {
+            formatdoc!(
+                "
+                <mx-reply>
+                    <blockquote>
+                        <a href=\"https://matrix.to/#/{room_id}/{event_id}\">In reply to</a>
+                        * <a href=\"https://matrix.to/#/{sender}\">{sender}</a>
+                        <br />
+                        {body}
+                    </blockquote>
+                </mx-reply>
+                ",
+                room_id = original_message.room_id,
+                event_id = original_message.event_id,
+                sender = original_message.sender,
+                body = formatted_or_plain_body(&content.formatted, &content.body),
+            )
+        }
+        MessageType::File(_) => {
+            formatdoc!(
+                "
+                <mx-reply>
+                    <blockquote>
+                        <a href=\"https://matrix.to/#/{room_id}/{event_id}\">In reply to</a>
+                        <a href=\"https://matrix.to/#/{sender}\">{sender}</a>
+                        <br />
+                        sent a file.
+                    </blockquote>
+                </mx-reply>
+                ",
+                room_id = original_message.room_id,
+                event_id = original_message.event_id,
+                sender = original_message.sender,
+            )
+        }
+        MessageType::Image(_) => {
+            formatdoc!(
+                "
+                <mx-reply>
+                    <blockquote>
+                        <a href=\"https://matrix.to/#/{room_id}/{event_id}\">In reply to</a>
+                        <a href=\"https://matrix.to/#/{sender}\">{sender}</a>
+                        <br />
+                        sent an image.
+                    </blockquote>
+                </mx-reply>
+                ",
+                room_id = original_message.room_id,
+                event_id = original_message.event_id,
+                sender = original_message.sender,
+            )
+        }
+        MessageType::Location(_) => {
+            formatdoc!(
+                "
+                <mx-reply>
+                    <blockquote>
+                        <a href=\"https://matrix.to/#/{room_id}/{event_id}\">In reply to</a>
+                        <a href=\"https://matrix.to/#/{sender}\">{sender}</a>
+                        <br />
+                        sent a location.
+                    </blockquote>
+                </mx-reply>
+                ",
+                room_id = original_message.room_id,
+                event_id = original_message.event_id,
+                sender = original_message.sender,
+            )
+        }
+        MessageType::Notice(content) => {
+            formatdoc!(
+                "
+                <mx-reply>
+                    <blockquote>
+                        <a href=\"https://matrix.to/#/{room_id}/{event_id}\">In reply to</a>
+                        <a href=\"https://matrix.to/#/{sender}\">{sender}</a>
+                        <br />
+                        {body}
+                    </blockquote>
+                </mx-reply>
+                ",
+                room_id = original_message.room_id,
+                event_id = original_message.event_id,
+                sender = original_message.sender,
+                body = formatted_or_plain_body(&content.formatted, &content.body),
+            )
+        }
+        MessageType::ServerNotice(content) => {
+            formatdoc!(
+                "
+                <mx-reply>
+                    <blockquote>
+                        <a href=\"https://matrix.to/#/{room_id}/{event_id}\">In reply to</a>
+                        <a href=\"https://matrix.to/#/{sender}\">{sender}</a>
+                        <br />
+                        {body}
+                    </blockquote>
+                </mx-reply>
+                ",
+                room_id = original_message.room_id,
+                event_id = original_message.event_id,
+                sender = original_message.sender,
+                body = content.body,
+            )
+        }
+        MessageType::Text(content) => {
+            formatdoc!(
+                "
+                <mx-reply>
+                    <blockquote>
+                        <a href=\"https://matrix.to/#/{room_id}/{event_id}\">In reply to</a>
+                        <a href=\"https://matrix.to/#/{sender}\">{sender}</a>
+                        <br />
+                        {body}
+                    </blockquote>
+                </mx-reply>
+                ",
+                room_id = original_message.room_id,
+                event_id = original_message.event_id,
+                sender = original_message.sender,
+                body = formatted_or_plain_body(&content.formatted, &content.body),
+            )
+        }
+        MessageType::Video(_) => {
+            formatdoc!(
+                "
+                <mx-reply>
+                    <blockquote>
+                        <a href=\"https://matrix.to/#/{room_id}/{event_id}\">In reply to</a>
+                        <a href=\"https://matrix.to/#/{sender}\">{sender}</a>
+                        <br />
+                        sent a video.
+                    </blockquote>
+                </mx-reply>
+                ",
+                room_id = original_message.room_id,
+                event_id = original_message.event_id,
+                sender = original_message.sender,
+            )
+        }
+        MessageType::_Custom(content) => {
+            formatdoc!(
+                "
+                <mx-reply>
+                    <blockquote>
+                        <a href=\"https://matrix.to/#/{room_id}/{event_id}\">In reply to</a>
+                        <a href=\"https://matrix.to/#/{sender}\">{sender}</a>
+                        <br />
+                        {body}
+                    </blockquote>
+                </mx-reply>
+                ",
+                room_id = original_message.room_id,
+                event_id = original_message.event_id,
+                sender = original_message.sender,
+                body = content.data["body"].as_str().unwrap_or(""),
+            )
+        }
+        #[cfg(feature = "unstable-pre-spec")]
+        MessageType::VerificationRequest(content) => {
+            formatdoc!(
+                "
+                <mx-reply>
+                    <blockquote>
+                        <a href=\"https://matrix.to/#/{server_name}/{event_id}\">In reply to</a>
+                        <a href=\"https://matrix.to/#/{sender}\">{sender}</a>
+                        <br />
+                        {body}
+                    </blockquote>
+                </mx-reply>
+                ",
+                server_name = original_message.room_id,
+                event_id = original_message.event_id,
+                sender = original_message.sender,
+                body = content.body,
+            )
+        }
+    }
+}
+
+fn formatted_or_plain_body<'a>(formatted: &'a Option<FormattedBody>, body: &'a str) -> &'a str {
+    if let Some(formatted_body) = formatted {
+        &formatted_body.body
+    } else {
+        body
+    }
+}