Add quote API

Sticky encryption rule, requiring that all replies to encrypted messages
are encrypted, applies only to messages with a quote now.

Co-Authored-By: B. Petersen <r10s@b44t.com>

deltachat-ffi/deltachat.h

@@ -3675,6 +3675,63 @@ void            dc_msg_set_location           (dc_msg_t* msg, double latitude, d
 void            dc_msg_latefiling_mediasize   (dc_msg_t* msg, int width, int height, int duration);
 
 
+/**
+ * Set the message replying to.
+ * This allows optionally to reply to an explicit message
+ * instead of replying implicitly to the end of the chat.
+ *
+ * dc_msg_set_quote() copies some basic data from the quoted message object
+ * so that dc_msg_get_quoted_text() will always work.
+ * dc_msg_get_quoted_msg() gets back the quoted message only if it is _not_ deleted.
+ *
+ * @memberof dc_msg_t
+ * @param msg The message object to set the reply to.
+ * @param quote The quote to set for msg.
+ */
+void             dc_msg_set_quote             (dc_msg_t* msg, const dc_msg_t* quote);
+
+
+/**
+ * Get quoted text, if any.
+ * You can use this function also check if there is a quote for a message.
+ *
+ * The text is a summary of the original text,
+ * similar to what is shown in the chatlist.
+ *
+ * If available, you can get the whole quoted message object using dc_msg_get_quoted_msg().
+ *
+ * @memberof dc_msg_t
+ * @param msg The message object.
+ * @return The quoted text or NULL if there is no quote.
+ *     Returned strings must be released using dc_str_unref().
+ */
+char*           dc_msg_get_quoted_text        (const dc_msg_t* msg);
+
+
+/**
+ * Get quoted message, if available.
+ * UIs might use this information to offer "jumping back" to the quoted message
+ * or to enrich displaying the quote.
+ *
+ * If this function returns NULL,
+ * this does not mean there is no quote for the message -
+ * it might also mean that a quote exist but the quoted message is deleted meanwhile.
+ * Therefore, do not use this function to check if there is a quote for a message.
+ * To check if a message has a quote, use dc_msg_get_quoted_text().
+ *
+ * To display the quote in the chat, use dc_msg_get_quoted_text() as a primary source,
+ * however, one might add information from the message object (eg. an image).
+ *
+ * It is not guaranteed that the message belong to the same chat.
+ *
+ * @memberof dc_msg_t
+ * @param msg The message object.
+ * @return The quoted message or NULL.
+ *     Must be freed using dc_msg_unref() after usage.
+ */
+dc_msg_t*       dc_msg_get_quoted_msg         (const dc_msg_t* msg);
+
+
 /**
  * @class dc_contact_t
  *

deltachat-ffi/src/lib.rs

@@ -2975,6 +2975,58 @@ pub unsafe extern "C" fn dc_msg_get_error(msg: *mut dc_msg_t) -> *mut libc::c_ch
     }
 }
 
+#[no_mangle]
+pub unsafe extern "C" fn dc_msg_set_quote(msg: *mut dc_msg_t, quote: *const dc_msg_t) {
+    if msg.is_null() {
+        eprintln!("ignoring careless call to dc_msg_set_quote()");
+        return;
+    }
+    let ffi_msg = &mut *msg;
+    let ffi_quote = &*quote;
+
+    ffi_msg
+        .message
+        .set_quote(&ffi_quote.message)
+        .log_err(&*ffi_msg.context, "failed to set quote")
+        .ok();
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn dc_msg_get_quoted_text(msg: *const dc_msg_t) -> *mut libc::c_char {
+    if msg.is_null() {
+        eprintln!("ignoring careless call to dc_msg_get_quoted_text()");
+        return ptr::null_mut();
+    }
+    let ffi_msg: &MessageWrapper = &*msg;
+    ffi_msg
+        .message
+        .quoted_text()
+        .map_or_else(ptr::null_mut, |s| s.strdup())
+}
+
+#[no_mangle]
+pub unsafe extern "C" fn dc_msg_get_quoted_msg(msg: *const dc_msg_t) -> *mut dc_msg_t {
+    if msg.is_null() {
+        eprintln!("ignoring careless call to dc_get_quoted_msg()");
+        return ptr::null_mut();
+    }
+    let ffi_msg: &MessageWrapper = &*msg;
+    let context = &*ffi_msg.context;
+    let res = block_on(async move {
+        ffi_msg
+            .message
+            .quoted_message(context)
+            .await
+            .log_err(context, "failed to get quoted message")
+            .unwrap_or(None)
+    });
+
+    match res {
+        Some(message) => Box::into_raw(Box::new(MessageWrapper { context, message })),
+        None => ptr::null_mut(),
+    }
+}
+
 // dc_contact_t
 
 /// FFI struct for [dc_contact_t]

python/src/deltachat/message.py

@@ -175,6 +175,27 @@ class Message(object):
         if ts:
             return datetime.utcfromtimestamp(ts)
 
+    @property
+    def quoted_text(self):
+        """Text inside the quote
+
+        :returns: Quoted text"""
+        return from_dc_charpointer(lib.dc_msg_get_quoted_text(self._dc_msg))
+
+    @property
+    def quote(self):
+        """Quote getter
+
+        :returns: Quoted message, if found in the database"""
+        msg = lib.dc_msg_get_quoted_msg(self._dc_msg)
+        if msg:
+            return Message(self.account, ffi.gc(msg, lib.dc_msg_unref))
+
+    @quote.setter
+    def quote(self, quoted_message):
+        """Quote setter"""
+        lib.dc_msg_set_quote(self._dc_msg, quoted_message._dc_msg)
+
     def get_mime_headers(self):
         """ return mime-header object for an incoming message.
 

python/tests/test_account.py

@@ -476,6 +476,21 @@ class TestOfflineChat:
         assert not res.is_ask_verifygroup()
         assert res.contact_id == 10
 
+    def test_quote(self, chat1):
+        """Offline quoting test"""
+        msg = Message.new_empty(chat1.account, "text")
+        msg.set_text("message")
+        assert msg.quoted_text is None
+
+        # Prepare message to assign it a Message-Id.
+        # Messages without Message-Id cannot be quoted.
+        msg = chat1.prepare_message(msg)
+
+        reply_msg = Message.new_empty(chat1.account, "text")
+        reply_msg.set_text("reply")
+        reply_msg.quote = msg
+        assert reply_msg.quoted_text == "message"
+
     def test_group_chat_many_members_add_remove(self, ac1, lp):
         lp.sec("ac1: creating group chat with 10 other members")
         chat = ac1.create_group_chat(name="title1")
@@ -1067,8 +1082,8 @@ class TestOnlineAccount:
         # Majority prefers encryption now
         assert msg5.is_encrypted()
 
-    @pytest.mark.xfail(reason="Sticky encryption rule was removed")
     def test_reply_encrypted(self, acfactory, lp):
+        """Test that replies to encrypted messages are encrypted."""
         ac1, ac2 = acfactory.get_two_online_accounts()
 
         lp.sec("ac1: create chat with ac2")
@@ -1096,26 +1111,26 @@ class TestOnlineAccount:
         print("ac2: e2ee_enabled={}".format(ac2.get_config("e2ee_enabled")))
         ac1.set_config("e2ee_enabled", "0")
 
-        # Set unprepared and unencrypted draft to test that it is not
-        # taken into account when determining whether last message is
-        # encrypted.
-        msg_draft = Message.new_empty(ac1, "text")
-        msg_draft.set_text("message2 -- should be encrypted")
-        chat.set_draft(msg_draft)
+        for quoted_msg in msg1, msg3:
+            # Save the draft with a quote.
+            # It should be encrypted if quoted message is encrypted.
+            msg_draft = Message.new_empty(ac1, "text")
+            msg_draft.set_text("message reply")
+            msg_draft.quote = quoted_msg
+            chat.set_draft(msg_draft)
 
-        # Get the draft, prepare and send it.
-        msg_draft = chat.get_draft()
-        msg_out = chat.prepare_message(msg_draft)
-        chat.send_prepared(msg_out)
+            # Get the draft, prepare and send it.
+            msg_draft = chat.get_draft()
+            msg_out = chat.prepare_message(msg_draft)
+            chat.send_prepared(msg_out)
 
-        chat.set_draft(None)
-        assert chat.get_draft() is None
+            chat.set_draft(None)
+            assert chat.get_draft() is None
 
-        lp.sec("wait for ac2 to receive message")
-        ev = ac2._evtracker.get_matching("DC_EVENT_INCOMING_MSG")
-        msg_in = ac2.get_message_by_id(ev.data2)
-        assert msg_in.text == "message2 -- should be encrypted"
-        assert msg_in.is_encrypted()
+            msg_in = ac2._evtracker.wait_next_incoming_message()
+            assert msg_in.text == "message reply"
+            assert msg_in.quoted_text == quoted_msg.text
+            assert msg_in.is_encrypted() == quoted_msg.is_encrypted()
 
     def test_saved_mime_on_received_message(self, acfactory, lp):
         ac1, ac2 = acfactory.get_two_online_accounts()
@@ -1869,6 +1884,45 @@ class TestOnlineAccount:
             # No renames should happen after explicit rename
             assert updated_name == "Renamed"
 
+    def test_group_quote(self, acfactory, lp):
+        """Test quoting in a group with a new member who have not seen the quoted message."""
+        ac1, ac2, ac3 = accounts = acfactory.get_many_online_accounts(3)
+        acfactory.introduce_each_other(accounts)
+        chat = ac1.create_group_chat(name="quote group")
+        chat.add_contact(ac2)
+
+        lp.sec("ac1: sending message")
+        out_msg = chat.send_text("hello")
+
+        lp.sec("ac2: receiving message")
+        msg = ac2._evtracker.wait_next_incoming_message()
+        assert msg.text == "hello"
+
+        chat.add_contact(ac3)
+        ac2._evtracker.wait_next_incoming_message()
+        ac3._evtracker.wait_next_incoming_message()
+
+        lp.sec("ac2: sending reply with a quote")
+        reply_msg = Message.new_empty(msg.chat.account, "text")
+        reply_msg.set_text("reply")
+        reply_msg.quote = msg
+        reply_msg = msg.chat.prepare_message(reply_msg)
+        assert reply_msg.quoted_text == "hello"
+        msg.chat.send_prepared(reply_msg)
+
+        lp.sec("ac3: receiving reply")
+        received_reply = ac3._evtracker.wait_next_incoming_message()
+        assert received_reply.text == "reply"
+        assert received_reply.quoted_text == "hello"
+        # ac3 was not in the group and has not received quoted message
+        assert received_reply.quote is None
+
+        lp.sec("ac1: receiving reply")
+        received_reply = ac1._evtracker.wait_next_incoming_message()
+        assert received_reply.text == "reply"
+        assert received_reply.quoted_text == "hello"
+        assert received_reply.quote.id == out_msg.id
+
 
 class TestGroupStressTests:
     def test_group_many_members_add_leave_remove(self, acfactory, lp):

src/chat.rs

@@ -753,7 +753,6 @@ impl Chat {
         timestamp: i64,
     ) -> Result<MsgId, Error> {
         let mut new_references = "".into();
-        let mut new_in_reply_to = "".into();
         let mut msg_id = 0;
         let mut to_id = 0;
         let mut location_id = 0;
@@ -828,8 +827,11 @@ impl Chat {
             if let Some((parent_rfc724_mid, parent_in_reply_to, parent_references)) =
                 self.id.get_parent_mime_headers(context).await
             {
-                if !parent_rfc724_mid.is_empty() {
-                    new_in_reply_to = parent_rfc724_mid.clone();
+                // "In-Reply-To:" is not changed if it is set manually.
+                // This does not affect "References:" header, it will contain "default parent" (the
+                // latest message in the thread) anyway.
+                if msg.in_reply_to.is_none() && !parent_rfc724_mid.is_empty() {
+                    msg.in_reply_to = Some(parent_rfc724_mid.clone());
                 }
 
                 // the whole list of messages referenced may be huge;
@@ -928,7 +930,7 @@ impl Chat {
                     msg.text.as_ref().cloned().unwrap_or_default(),
                     msg.param.to_string(),
                     msg.hidden,
-                    new_in_reply_to,
+                    msg.in_reply_to.as_deref().unwrap_or_default(),
                     new_references,
                     location_id as i32,
                     ephemeral_timer,

src/format_flowed.rs

@@ -21,21 +21,28 @@
 /// length. However, this should be rare and should not result in
 /// immediate mail rejection: SMTP (RFC 2821) limit is 998 characters,
 /// and Spam Assassin limit is 78 characters.
-fn format_line_flowed(line: &str) -> String {
+fn format_line_flowed(line: &str, prefix: &str) -> String {
     let mut result = String::new();
-    let mut buffer = String::new();
+    let mut buffer = prefix.to_string();
     let mut after_space = false;
 
     for c in line.chars() {
         if c == ' ' {
             buffer.push(c);
             after_space = true;
+        } else if c == '>' {
+            if buffer.is_empty() {
+                // Space stuffing, see RFC 3676
+                buffer.push(' ');
+            }
+            buffer.push(c);
+            after_space = false;
         } else {
-            if after_space && buffer.len() >= 72 && !c.is_whitespace() && c != '>' {
+            if after_space && buffer.len() >= 72 && !c.is_whitespace() {
                 // Flush the buffer and insert soft break (SP CRLF).
                 result += &buffer;
                 result += "\r\n";
-                buffer = String::new();
+                buffer = prefix.to_string();
             }
             buffer.push(c);
             after_space = false;
@@ -44,6 +51,28 @@ fn format_line_flowed(line: &str) -> String {
     result + &buffer
 }
 
+fn format_flowed_prefix(text: &str, prefix: &str) -> String {
+    let mut result = String::new();
+
+    for line in text.split('\n') {
+        if !result.is_empty() {
+            result += "\r\n";
+        }
+        let line = line.trim_end();
+        if prefix.len() + line.len() > 78 {
+            result += &format_line_flowed(line, prefix);
+        } else {
+            result += prefix;
+            if prefix.is_empty() && line.starts_with('>') {
+                // Space stuffing, see RFC 3676
+                result.push(' ');
+            }
+            result += line;
+        }
+    }
+    result
+}
+
 /// Returns text formatted according to RFC 3767 (format=flowed).
 ///
 /// This function accepts text separated by LF, but returns text
@@ -52,20 +81,12 @@ fn format_line_flowed(line: &str) -> String {
 /// RFC 2646 technique is used to insert soft line breaks, so DelSp
 /// SHOULD be set to "no" when sending.
 pub fn format_flowed(text: &str) -> String {
-    let mut result = String::new();
+    format_flowed_prefix(text, "")
+}
 
-    for line in text.split('\n') {
-        if !result.is_empty() {
-            result += "\r\n";
-        }
-        let line = line.trim_end();
-        if line.len() > 78 {
-            result += &format_line_flowed(line);
-        } else {
-            result += line;
-        }
-    }
-    result
+/// Same as format_flowed(), but adds "> " prefix to each line.
+pub fn format_flowed_quote(text: &str) -> String {
+    format_flowed_prefix(text, "> ")
 }
 
 /// Joins lines in format=flowed text.
@@ -122,6 +143,9 @@ mod tests {
                         To decrypt and use your key, open the message in an Autocrypt-compliant \r\n\
                         client and enter the setup code presented on the generating device.";
         assert_eq!(format_flowed(text), expected);
+
+        let text = "> Not a quote";
+        assert_eq!(format_flowed(text), " > Not a quote");
     }
 
     #[test]
@@ -133,4 +157,21 @@ mod tests {
                         unwrapped on the receiver";
         assert_eq!(unformat_flowed(text, false), expected);
     }
+
+    #[test]
+    fn test_format_flowed_quote() {
+        let quote = "this is a quoted line";
+        let expected = "> this is a quoted line";
+        assert_eq!(format_flowed_quote(quote), expected);
+
+        let quote = "> foo bar baz";
+        let expected = "> > foo bar baz";
+        assert_eq!(format_flowed_quote(quote), expected);
+
+        let quote = "this is a very long quote that should be wrapped using format=flowed and unwrapped on the receiver";
+        let expected =
+            "> this is a very long quote that should be wrapped using format=flowed and \r\n\
+            > unwrapped on the receiver";
+        assert_eq!(format_flowed_quote(quote), expected);
+    }
 }

src/message.rs

@@ -741,6 +741,55 @@ impl Message {
         self.update_param(context).await;
     }
 
+    /// Sets message quote.
+    ///
+    /// Message-Id is used to set Reply-To field, message text is used for quote.
+    ///
+    /// Encryption is required if quoted message was encrypted.
+    ///
+    /// The message itself is not required to exist in the database,
+    /// it may even be deleted from the database by the time the message is prepared.
+    pub fn set_quote(&mut self, quote: &Message) -> Result<(), Error> {
+        ensure!(
+            !quote.rfc724_mid.is_empty(),
+            "Message without Message-Id cannot be quoted"
+        );
+        self.in_reply_to = Some(quote.rfc724_mid.clone());
+
+        if quote
+            .param
+            .get_bool(Param::GuaranteeE2ee)
+            .unwrap_or_default()
+        {
+            self.param.set(Param::GuaranteeE2ee, "1");
+        }
+
+        self.param
+            .set(Param::Quote, quote.get_text().unwrap_or_default());
+
+        Ok(())
+    }
+
+    pub fn quoted_text(&self) -> Option<String> {
+        self.param.get(Param::Quote).map(|s| s.to_string())
+    }
+
+    pub async fn quoted_message(&self, context: &Context) -> Result<Option<Message>, Error> {
+        if self.param.get(Param::Quote).is_some() {
+            if let Some(in_reply_to) = &self.in_reply_to {
+                if let Some((_folder, _uid, msg_id)) = rfc724_mid_exists(
+                    context,
+                    in_reply_to.trim_start_matches('<').trim_end_matches('>'),
+                )
+                .await?
+                {
+                    return Ok(Some(Message::load_from_db(context, msg_id).await?));
+                }
+            }
+        }
+        Ok(None)
+    }
+
     pub async fn update_param(&mut self, context: &Context) -> bool {
         context
             .sql
@@ -2014,4 +2063,43 @@ mod tests {
         }
         assert!(has_image);
     }
+
+    #[async_std::test]
+    async fn test_quote() {
+        use crate::config::Config;
+
+        let d = test::TestContext::new().await;
+        let ctx = &d.ctx;
+
+        let contact = Contact::create(ctx, "", "dest@example.com")
+            .await
+            .expect("failed to create contact");
+
+        let res = ctx
+            .set_config(Config::ConfiguredAddr, Some("self@example.com"))
+            .await;
+        assert!(res.is_ok());
+
+        let chat = chat::create_by_contact_id(ctx, contact).await.unwrap();
+
+        let mut msg = Message::new(Viewtype::Text);
+        msg.set_text(Some("Quoted message".to_string()));
+
+        // Prepare message for sending, so it gets a Message-Id.
+        assert!(msg.rfc724_mid.is_empty());
+        let msg_id = chat::prepare_msg(ctx, chat, &mut msg).await.unwrap();
+        let msg = Message::load_from_db(ctx, msg_id).await.unwrap();
+        assert!(!msg.rfc724_mid.is_empty());
+
+        let mut msg2 = Message::new(Viewtype::Text);
+        msg2.set_quote(&msg).expect("can't set quote");
+        assert!(msg2.quoted_text() == msg.get_text());
+
+        let quoted_msg = msg2
+            .quoted_message(ctx)
+            .await
+            .expect("error while retrieving quoted message")
+            .expect("quoted message not found");
+        assert!(quoted_msg.get_text() == msg2.quoted_text());
+    }
 }

src/mimefactory.rs

@@ -11,7 +11,7 @@ use crate::dc_tools::*;
 use crate::e2ee::*;
 use crate::ephemeral::Timer as EphemeralTimer;
 use crate::error::{bail, ensure, format_err, Error};
-use crate::format_flowed::format_flowed;
+use crate::format_flowed::{format_flowed, format_flowed_quote};
 use crate::location;
 use crate::message::{self, Message};
 use crate::mimeparser::SystemMessage;
@@ -917,12 +917,17 @@ impl<'a, 'b> MimeFactory<'a, 'b> {
             }
         };
 
+        let quoted_text = self
+            .msg
+            .quoted_text()
+            .map(|quote| format_flowed_quote(&quote) + "\r\n");
         let flowed_text = format_flowed(final_text);
 
         let footer = &self.selfstatus;
         let message_text = format!(
-            "{}{}{}{}{}",
+            "{}{}{}{}{}{}",
             fwdhint.unwrap_or_default(),
+            quoted_text.unwrap_or_default(),
             escape_message_footer_marks(&flowed_text),
             if !final_text.is_empty() && !footer.is_empty() {
                 "\r\n\r\n"

src/mimeparser.rs

@@ -704,8 +704,8 @@ impl MimeMessage {
                             }
                         };
 
-                        let (simplified_txt, is_forwarded) = if decoded_data.is_empty() {
-                            ("".into(), false)
+                        let (simplified_txt, is_forwarded, top_quote) = if decoded_data.is_empty() {
+                            ("".to_string(), false, None)
                         } else {
                             let is_html = mime_type == mime::TEXT_HTML;
                             let out = if is_html {
@@ -723,7 +723,7 @@ impl MimeMessage {
                             false
                         };
 
-                        let simplified_txt = if mime_type.type_() == mime::TEXT
+                        let (simplified_txt, simplified_quote) = if mime_type.type_() == mime::TEXT
                             && mime_type.subtype() == mime::PLAIN
                             && is_format_flowed
                         {
@@ -732,9 +732,11 @@ impl MimeMessage {
                             } else {
                                 false
                             };
-                            unformat_flowed(&simplified_txt, delsp)
+                            let unflowed_text = unformat_flowed(&simplified_txt, delsp);
+                            let unflowed_quote = top_quote.map(|q| unformat_flowed(&q, delsp));
+                            (unflowed_text, unflowed_quote)
                         } else {
-                            simplified_txt
+                            (simplified_txt, top_quote)
                         };
 
                         if !simplified_txt.is_empty() {
@@ -742,6 +744,9 @@ impl MimeMessage {
                             part.typ = Viewtype::Text;
                             part.mimetype = Some(mime_type);
                             part.msg = simplified_txt;
+                            if let Some(quote) = simplified_quote {
+                                part.param.set(Param::Quote, quote);
+                            }
                             part.msg_raw = Some(decoded_data);
                             self.do_add_single_part(part);
                         }
@@ -2119,12 +2124,39 @@ CWt6wx7fiLp0qS9RrX75g6Gqw7nfCs6EcBERcIPt7DTe8VStJwf3LWqVwxl4gQl46yhfoqwEO+I=
         assert!(test.is_empty());
     }
 
-    #[test]
-    fn test_mime_parse_format_flowed() {
-        let mime_type = "text/plain; charset=utf-8; Format=Flowed; DelSp=No"
-            .parse::<mime::Mime>()
+    #[async_std::test]
+    async fn parse_format_flowed_quote() {
+        let context = TestContext::new().await;
+        let raw = br##"Content-Type: text/plain; charset=utf-8; format=flowed; delsp=no
+Subject: Re: swipe-to-reply
+MIME-Version: 1.0
+In-Reply-To: <bar@example.org>
+Date: Tue, 06 Oct 2020 00:00:00 +0000
+Chat-Version: 1.0
+Message-ID: <foo@example.org>
+To: bob <bob@example.org>
+From: alice <alice@example.org>
+
+> Long 
+> quote.
+
+Reply
+"##;
+
+        let message = MimeMessage::from_bytes(&context.ctx, &raw[..])
+            .await
             .unwrap();
-        let format_param = mime_type.get_param("format").unwrap();
-        assert_eq!(format_param.as_str().to_ascii_lowercase(), "flowed");
+        assert_eq!(
+            message.get_subject(),
+            Some("Re: swipe-to-reply".to_string())
+        );
+
+        assert_eq!(message.parts.len(), 1);
+        assert_eq!(message.parts[0].typ, Viewtype::Text);
+        assert_eq!(
+            message.parts[0].param.get(Param::Quote).unwrap(),
+            "Long quote."
+        );
+        assert_eq!(message.parts[0].msg, "Reply");
     }
 }

src/param.rs

@@ -53,6 +53,9 @@ pub enum Param {
     /// For Messages
     Forwarded = b'a',
 
+    /// For Messages: quoted text.
+    Quote = b'q',
+
     /// For Messages
     Cmd = b'S',
 

src/simplify.rs

@@ -1,3 +1,5 @@
+use itertools::Itertools;
+
 // protect lines starting with `--` against being treated as a footer.
 // for that, we insert a ZERO WIDTH SPACE (ZWSP, 0x200B);
 // this should be invisible on most systems and there is no need to unescape it again
@@ -64,7 +66,7 @@ fn split_lines(buf: &str) -> Vec<&str> {
 
 /// Simplify message text for chat display.
 /// Remove quotes, signatures, trailing empty lines etc.
-pub fn simplify(mut input: String, is_chat_message: bool) -> (String, bool) {
+pub fn simplify(mut input: String, is_chat_message: bool) -> (String, bool, Option<String>) {
     input.retain(|c| c != '\r');
     let lines = split_lines(&input);
     let (lines, is_forwarded) = skip_forward_header(&lines);
@@ -72,25 +74,25 @@ pub fn simplify(mut input: String, is_chat_message: bool) -> (String, bool) {
     let original_lines = &lines;
 
     let lines = remove_message_footer(lines);
+    let (lines, top_quote) = remove_top_quote(lines);
 
     let text = if is_chat_message {
         render_message(lines, false, false)
     } else {
         let (lines, has_nonstandard_footer) = remove_nonstandard_footer(lines);
         let (lines, has_bottom_quote) = remove_bottom_quote(lines);
-        let (lines, has_top_quote) = remove_top_quote(lines);
 
         if lines.iter().all(|it| it.trim().is_empty()) {
             render_message(original_lines, false, false)
         } else {
             render_message(
                 lines,
-                has_top_quote,
+                top_quote.is_some(),
                 has_nonstandard_footer || has_bottom_quote,
             )
         }
     };
-    (text, is_forwarded)
+    (text, is_forwarded, top_quote)
 }
 
 /// Skips "forwarded message" header.
@@ -134,11 +136,15 @@ fn remove_bottom_quote<'a>(lines: &'a [&str]) -> (&'a [&'a str], bool) {
 }
 
 #[allow(clippy::indexing_slicing)]
-fn remove_top_quote<'a>(lines: &'a [&str]) -> (&'a [&'a str], bool) {
+fn remove_top_quote<'a>(lines: &'a [&str]) -> (&'a [&'a str], Option<String>) {
+    let mut first_quoted_line = 0;
     let mut last_quoted_line = None;
     let mut has_quoted_headline = false;
     for (l, line) in lines.iter().enumerate() {
         if is_plain_quote(line) {
+            if last_quoted_line.is_none() {
+                first_quoted_line = l;
+            }
             last_quoted_line = Some(l)
         } else if !is_empty_line(line) {
             if is_quoted_headline(line) && !has_quoted_headline && last_quoted_line.is_none() {
@@ -150,9 +156,20 @@ fn remove_top_quote<'a>(lines: &'a [&str]) -> (&'a [&'a str], bool) {
         }
     }
     if let Some(last_quoted_line) = last_quoted_line {
-        (&lines[last_quoted_line + 1..], true)
+        (
+            &lines[last_quoted_line + 1..],
+            Some(
+                lines[first_quoted_line..last_quoted_line + 1]
+                    .iter()
+                    .map(|s| {
+                        s.strip_prefix(">")
+                            .map_or(*s, |u| u.strip_prefix(" ").unwrap_or(u))
+                    })
+                    .join("\n"),
+            ),
+        )
     } else {
-        (lines, false)
+        (lines, None)
     }
 }
 
@@ -231,7 +248,7 @@ mod tests {
         #[test]
         // proptest does not support [[:graphical:][:space:]] regex.
         fn test_simplify_plain_text_fuzzy(input in "[!-~\t \n]+") {
-            let (output, _is_forwarded) = simplify(input, true);
+            let (output, _is_forwarded, _) = simplify(input, true);
             assert!(output.split('\n').all(|s| s != "-- "));
         }
     }
@@ -239,7 +256,7 @@ mod tests {
     #[test]
     fn test_dont_remove_whole_message() {
         let input = "\n------\nFailed\n------\n\nUh-oh, this workflow did not succeed!\n\nlots of other text".to_string();
-        let (plain, is_forwarded) = simplify(input, false);
+        let (plain, is_forwarded, _) = simplify(input, false);
         assert_eq!(
             plain,
             "------\nFailed\n------\n\nUh-oh, this workflow did not succeed!\n\nlots of other text"
@@ -250,7 +267,7 @@ mod tests {
     #[test]
     fn test_chat_message() {
         let input = "Hi! How are you?\n\n---\n\nI am good.\n-- \nSent with my Delta Chat Messenger: https://delta.chat".to_string();
-        let (plain, is_forwarded) = simplify(input, true);
+        let (plain, is_forwarded, _) = simplify(input, true);
         assert_eq!(plain, "Hi! How are you?\n\n---\n\nI am good.");
         assert!(!is_forwarded);
     }
@@ -258,7 +275,7 @@ mod tests {
     #[test]
     fn test_simplify_trim() {
         let input = "line1\n\r\r\rline2".to_string();
-        let (plain, is_forwarded) = simplify(input, false);
+        let (plain, is_forwarded, _) = simplify(input, false);
 
         assert_eq!(plain, "line1\nline2");
         assert!(!is_forwarded);
@@ -267,7 +284,7 @@ mod tests {
     #[test]
     fn test_simplify_forwarded_message() {
         let input = "---------- Forwarded message ----------\r\nFrom: test@example.com\r\n\r\nForwarded message\r\n-- \r\nSignature goes here".to_string();
-        let (plain, is_forwarded) = simplify(input, false);
+        let (plain, is_forwarded, _) = simplify(input, false);
 
         assert_eq!(plain, "Forwarded message");
         assert!(is_forwarded);
@@ -287,17 +304,17 @@ mod tests {
 
     #[test]
     fn test_remove_top_quote() {
-        let (lines, has_top_quote) = remove_top_quote(&["> first", "> second"]);
+        let (lines, top_quote) = remove_top_quote(&["> first", "> second"]);
         assert!(lines.is_empty());
-        assert!(has_top_quote);
+        assert_eq!(top_quote.unwrap(), "first\nsecond");
 
-        let (lines, has_top_quote) = remove_top_quote(&["> first", "> second", "not a quote"]);
+        let (lines, top_quote) = remove_top_quote(&["> first", "> second", "not a quote"]);
         assert_eq!(lines, &["not a quote"]);
-        assert!(has_top_quote);
+        assert_eq!(top_quote.unwrap(), "first\nsecond");
 
-        let (lines, has_top_quote) = remove_top_quote(&["not a quote", "> first", "> second"]);
+        let (lines, top_quote) = remove_top_quote(&["not a quote", "> first", "> second"]);
         assert_eq!(lines, &["not a quote", "> first", "> second"]);
-        assert!(!has_top_quote);
+        assert!(top_quote.is_none());
     }
 
     #[test]
@@ -312,41 +329,41 @@ mod tests {
     #[test]
     fn test_remove_message_footer() {
         let input = "text\n--\nno footer".to_string();
-        let (plain, _) = simplify(input, true);
+        let (plain, _, _) = simplify(input, true);
         assert_eq!(plain, "text\n--\nno footer");
 
         let input = "text\n\n--\n\nno footer".to_string();
-        let (plain, _) = simplify(input, true);
+        let (plain, _, _) = simplify(input, true);
         assert_eq!(plain, "text\n\n--\n\nno footer");
 
         let input = "text\n\n-- no footer\n\n".to_string();
-        let (plain, _) = simplify(input, true);
+        let (plain, _, _) = simplify(input, true);
         assert_eq!(plain, "text\n\n-- no footer");
 
         let input = "text\n\n--\nno footer\n-- \nfooter".to_string();
-        let (plain, _) = simplify(input, true);
+        let (plain, _, _) = simplify(input, true);
         assert_eq!(plain, "text\n\n--\nno footer");
 
         let input = "text\n\n--\ntreated as footer when unescaped".to_string();
-        let (plain, _) = simplify(input.clone(), true);
+        let (plain, _, _) = simplify(input.clone(), true);
         assert_eq!(plain, "text"); // see remove_message_footer() for some explanations
         let escaped = escape_message_footer_marks(&input);
-        let (plain, _) = simplify(escaped, true);
+        let (plain, _, _) = simplify(escaped, true);
         assert_eq!(plain, "text\n\n--\ntreated as footer when unescaped");
 
         // Nonstandard footer sent by https://siju.es/
         let input = "Message text here\n---Desde mi teléfono con SIJÚ\n\nQuote here".to_string();
-        let (plain, _) = simplify(input.clone(), false);
+        let (plain, _, _) = simplify(input.clone(), false);
         assert_eq!(plain, "Message text here [...]");
-        let (plain, _) = simplify(input.clone(), true);
+        let (plain, _, _) = simplify(input.clone(), true);
         assert_eq!(plain, input);
 
         let input = "--\ntreated as footer when unescaped".to_string();
-        let (plain, _) = simplify(input.clone(), true);
+        let (plain, _, _) = simplify(input.clone(), true);
         assert_eq!(plain, ""); // see remove_message_footer() for some explanations
 
         let escaped = escape_message_footer_marks(&input);
-        let (plain, _) = simplify(escaped, true);
+        let (plain, _, _) = simplify(escaped, true);
         assert_eq!(plain, "--\ntreated as footer when unescaped");
     }
 }