From ad3245f88434456feef27e45fcd6ed86dd7c47ba Mon Sep 17 00:00:00 2001
From: "Philip (a-0)" <@ph:a-0.me>
Date: Sat, 3 Sep 2022 21:02:22 +0200
Subject: [PATCH] Introduced e-mail parsing and minor error handling for
 encoding or parsing issues

---
 Cargo.toml    |  1 +
 src/main.rs   | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++-
 src/matrix.rs |  4 ++--
 3 files changed, 58 insertions(+), 3 deletions(-)

diff --git a/Cargo.toml b/Cargo.toml
index 61ff008..a41a6da 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -11,6 +11,7 @@ serde = "1.0.144"
 serde_yaml = "0.9.10"
 
 postbus = "0.2.0"
+mailparse = "0.13.8"
 ruma = "0.6.4"
 matrix-sdk = "0.5.0"
 
diff --git a/src/main.rs b/src/main.rs
index 1e2c2f6..b09859b 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,6 @@
 use std::sync::Arc;
 use async_trait::async_trait;
+use mailparse::ParsedMail;
 use matrix_sdk::Client;
 use postbus::{Handler, SmtpService, SmtpState, command::Mailbox};
 use crate::config::Mapping;
@@ -56,8 +57,61 @@ impl Handler for ToMatrixConverter {
     }
     async fn save(&self, state: &SmtpState) -> bool {
         for recipient in &state.recipients {
-            matrix::send(&state.from, &recipient, &state.data, &self.matrix_clients, &self.mappings).await;
+            match mailparse::parse_mail(state.data.as_bytes()) {
+                Ok(mail) => matrix::send(&state.from, &recipient, 
+                    &mail_to_plain_message(&mail, &state.from, &recipient), 
+                    &mail_to_html_message(&mail, &state.from, &recipient), 
+                    &self.matrix_clients, &self.mappings).await,
+                Err(e) => {
+                    println!("{}", e);
+                    matrix::send(&state.from, &recipient, 
+                        &format!("Error parsing e-mail. This is a dump of the whole data section:\n{}", &state.data), 
+                        &format!("Error parsing e-mail. This is a dump of the whole data section:<br>{}", &state.data), 
+                        &self.matrix_clients, &self.mappings).await;
+                }
+            }
         }
         true
     }
+}
+
+fn mail_to_plain_message(mail: &ParsedMail, from: &Option<Mailbox>, to: &Mailbox) -> String {
+    format!("From {} to {}\nSubject: {}\n---\n{}", 
+        match from {
+            Some(fr) => mailbox_to_addr(fr),
+            None => "[unknown sender]".to_string(),
+        }, 
+        mailbox_to_addr(to), 
+        get_subject(mail),
+        match mail.get_body() {
+            Ok(body) => body,
+            Err(e) => "WARNING! E-mail content could not be decoded.".to_string(),
+        }
+    )
+}
+fn mail_to_html_message(mail: &ParsedMail, from: &Option<Mailbox>, to: &Mailbox) -> String {
+    format!("<b>From</b> {} <b>to</b> {}<br><b>Subject:</b> {}<hline>{}", 
+        match from {
+            Some(fr) => mailbox_to_addr(fr),
+            None => "[unknown sender]".to_string(),
+        }, 
+        mailbox_to_addr(to), 
+        get_subject(mail),
+        match mail.get_body() {
+            Ok(body) => body,
+            Err(e) => "<b>WARNING! E-mail content could not be decoded.<b>".to_string(),
+        }
+    )
+}
+
+fn get_subject(mail: &ParsedMail) -> String {
+    for header in &mail.headers {
+        if header.get_key() == "Subject" {
+            return header.get_value();
+        }
+    }
+    return String::from("[no subject found]");
+}
+pub fn mailbox_to_addr(mb: &Mailbox) -> String {
+    format!("{}@{}", mb.local, mb.domain.0)
 }
\ No newline at end of file
diff --git a/src/matrix.rs b/src/matrix.rs
index e43121c..eaca4aa 100644
--- a/src/matrix.rs
+++ b/src/matrix.rs
@@ -84,7 +84,7 @@ async fn client_from_mxid(mxid: &str, clients: &Vec<Client>) -> Option<Client> {
     None
 }
 
-pub async fn send(from_mail: &Option<Mailbox>, recipient: &Mailbox, content: &str, clients: &Vec<Client>, mappings: &Vec<Mapping>) {
+pub async fn send(from_mail: &Option<Mailbox>, recipient: &Mailbox, plain_content: &str, html_content: &str, clients: &Vec<Client>, mappings: &Vec<Mapping>) {
     for mapping in mappings {
         let mut applies = true;
 
@@ -151,7 +151,7 @@ pub async fn send(from_mail: &Option<Mailbox>, recipient: &Mailbox, content: &st
                             continue;
                         }
                     };
-                    match room.send(RoomMessageEventContent::text_html(content, content), None).await {
+                    match room.send(RoomMessageEventContent::text_html(plain_content, html_content), None).await {
                         Ok(_) => (),
                         Err(_e) => println!("Sending message failed"),
                     };