From dd55b04186c295319602d95d2486225570ed3591 Mon Sep 17 00:00:00 2001
From: Robin Krahl <robin.krahl@ireas.org>
Date: Mon, 7 Jan 2019 20:55:37 +0000
Subject: Implement QR code decoding using zbarimg

---
 src/main.rs | 52 ++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 46 insertions(+), 6 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index b3fb3f3..9c2a8c1 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -7,11 +7,13 @@ use std::fs;
 use std::io;
 use std::path;
 use std::process;
+use std::string;
 
 #[derive(Debug)]
 enum Error {
     IoError(io::Error),
     Error(String),
+    Utf8Error(string::FromUtf8Error),
 }
 
 impl fmt::Display for Error {
@@ -19,6 +21,7 @@ impl fmt::Display for Error {
         match *self {
             Error::IoError(ref err) => write!(f, "IO error: {}", err),
             Error::Error(ref string) => write!(f, "Error: {}", string),
+            Error::Utf8Error(ref err) => write!(f, "UTF-8 error: {}", err),
         }
     }
 }
@@ -35,6 +38,23 @@ impl From<io::Error> for Error {
     }
 }
 
+impl From<(&str, process::ExitStatus)> for Error {
+    fn from(data: (&str, process::ExitStatus)) -> Error {
+        let (command, status) = data;
+        let msg = match status.code() {
+            Some(code) => format!("{} failed with error code {}", command, code),
+            None => format!("{} was terminated by a signal", command),
+        };
+        Error::Error(msg)
+    }
+}
+
+impl From<string::FromUtf8Error> for Error {
+    fn from(error: string::FromUtf8Error) -> Error {
+        Error::Utf8Error(error)
+    }
+}
+
 #[derive(Debug)]
 struct Options {
     slot: u8,
@@ -82,13 +102,32 @@ fn import_qr_code() -> Result<path::PathBuf, Error> {
         temp.release();
         Ok(path)
     } else {
-        match status.code() {
-            Some(code) => Err(Error::Error(format!(
-                "import failed with error code {}",
-                code
-            ))),
-            None => Err(Error::from("import was terminated by a signal")),
+        Err(Error::from(("import", status)))
+    }
+}
+
+fn decode_qr_code(path: &path::Path) -> Result<String, Error> {
+    let output = process::Command::new("zbarimg")
+        .arg("--quiet")
+        .arg("--raw")
+        .arg(path)
+        .output()?;
+    if output.status.success() {
+        let output = String::from_utf8(output.stdout)?;
+        let urls = output
+            .split("\n")
+            .filter(|url| url.starts_with("otpauth://"))
+            .collect::<Vec<&str>>();
+        if urls.is_empty() {
+            Err(Error::from("Could not find an otpauth QR code"))
+        } else {
+            if urls.len() > 1 {
+                println!("Found more than otpauth QR code, using the first one.");
+            }
+            Ok(urls[0].to_string())
         }
+    } else {
+        Err(Error::from(("zbarimg", output.status)))
     }
 }
 
@@ -97,6 +136,7 @@ fn run(options: Options) -> Result<(), Error> {
         Some(ref file) => path::PathBuf::from(file),
         None => import_qr_code()?,
     };
+    println!("{}", decode_qr_code(&path)?);
     if options.file.is_none() {
         fs::remove_file(&path)?;
     }
-- 
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