1 files changed, 89 insertions, 0 deletions
diff --git a/src/backends/stdio.rs b/src/backends/stdio.rs
new file mode 100644
index 0000000..6838ef1
--- /dev/null
+++ b/src/backends/stdio.rs
@@ -0,0 +1,89 @@
+// Copyright (C) 2019 Robin Krahl <robin.krahl@ireas.org>
+// SPDX-License-Identifier: MIT
+
+use std::io::{self, Write};
+
+use crate::{Choice, Input, Message, Password, Question, Result};
+
+/// The fallback backend using standard input and output.
+///
+/// This backend is intended as a fallback backend to use if no other backend is available.  The
+/// dialogs are printed to the standard output and user input is read from the standard input.
+#[derive(Debug)]
+pub struct Stdio {}
+
+impl Stdio {
+    /// Creates a new `Stdio` instance.
+    pub fn new() -> Stdio {
+        Stdio {}
+    }
+}
+
+impl AsRef<Stdio> for Stdio {
+    fn as_ref(&self) -> &Self {
+        self
+    }
+}
+
+fn print_title(title: &Option<String>) {
+    if let Some(ref title) = title {
+        println!("{}", title);
+        println!("{}", "=".repeat(title.len()));
+    }
+}
+
+fn read_input() -> Result<String> {
+    let mut input = String::new();
+    io::stdin().read_line(&mut input)?;
+    Ok(input.trim_end_matches("\n").to_string())
+}
+
+fn parse_choice(input: &str) -> Choice {
+    match input.to_lowercase().as_ref() {
+        "y" => Choice::Yes,
+        "yes" => Choice::Yes,
+        "n" => Choice::No,
+        "no" => Choice::No,
+        _ => Choice::Cancel,
+    }
+}
+
+impl super::Backend for Stdio {
+    fn show_input(&self, input: &Input) -> Result<Option<String>> {
+        print_title(&input.title);
+        if let Some(ref default) = input.default {
+            print!("{} [default: {}]: ", input.text, default);
+        } else {
+            print!("{}: ", input.text);
+        }
+        io::stdout().flush()?;
+
+        let user_input = read_input()?;
+        if user_input.is_empty() {
+            if let Some(ref default) = input.default {
+                return Ok(Some(default.to_string()));
+            }
+        }
+        Ok(Some(user_input))
+    }
+
+    fn show_message(&self, message: &Message) -> Result<()> {
+        print_title(&message.title);
+        println!("{}", message.text);
+        Ok(())
+    }
+
+    fn show_password(&self, password: &Password) -> Result<Option<String>> {
+        print_title(&password.title);
+        print!("{}: ", password.text);
+        io::stdout().flush()?;
+        Ok(Some(rpassword::read_password()?))
+    }
+
+    fn show_question(&self, question: &Question) -> Result<Choice> {
+        print_title(&question.title);
+        print!("{} [y/n]: ", question.text);
+        io::stdout().flush()?;
+        Ok(parse_choice(&read_input()?))
+    }
+}