[pbs-devel] [PATCH proxmox v3] router: cli: added `ask_for_confirmation` helper

[Gabriel Goller <g.goller@proxmox.com>]

Added `ask_for_confirmation` helper that outputs a prompt and
lets the user confirm or deny it. Also added localization using
`libc::nl_langinfo()` to match/show a `yes` or `no` in the correct
language.
Implemented to close #4763.

Signed-off-by: Gabriel Goller <g.goller@proxmox.com>
---

update v3:
 - added localization using `libc::nl_langinfo`

note: skipped to version 3, so that the whole patch series has 
      the same version number.

 proxmox-router/Cargo.toml     |  1 +
 proxmox-router/src/cli/mod.rs | 34 +++++++++++++++++++++++++++++++++-
 2 files changed, 34 insertions(+), 1 deletion(-)

diff --git a/proxmox-router/Cargo.toml b/proxmox-router/Cargo.toml
index 1c08ce2..e0d67d0 100644
--- a/proxmox-router/Cargo.toml
+++ b/proxmox-router/Cargo.toml
@@ -19,6 +19,7 @@ percent-encoding.workspace = true
 serde_json.workspace = true
 serde.workspace = true
 unicode-width ="0.1.8"
+regex.workspace = true
 
 # cli:
 tokio = { workspace = true, features = [], optional = true }
diff --git a/proxmox-router/src/cli/mod.rs b/proxmox-router/src/cli/mod.rs
index 208df4a..1dcfaf0 100644
--- a/proxmox-router/src/cli/mod.rs
+++ b/proxmox-router/src/cli/mod.rs
@@ -12,7 +12,10 @@
 //! - Ability to create interactive commands (using ``rustyline``)
 //! - Supports complex/nested commands
 
-use std::collections::HashMap;
+use std::{
+    collections::HashMap,
+    io::{self, Write},
+};
 
 use crate::ApiMethod;
 
@@ -62,6 +65,35 @@ pub fn init_cli_logger(env_var_name: &str, default_log_level: &str) {
     .init();
 }
 
+pub fn ask_for_confirmation(query: String) -> Result<(), io::Error> {
+    use std::ffi::CStr;
+    let yes_expr = unsafe { CStr::from_ptr(libc::nl_langinfo(libc::YESEXPR)) }
+        .to_str()
+        .unwrap_or("^[yY]$");
+    let no_expr = unsafe { CStr::from_ptr(libc::nl_langinfo(libc::NOEXPR)) }
+        .to_str()
+        .unwrap_or("^[nN]$");
+
+    let n = no_expr.chars().find(|c| c.is_uppercase()).unwrap_or('N');
+    let y = yes_expr.chars().find(|c| c.is_uppercase()).unwrap_or('Y');
+    print!("{query} [{y}/{n}]: ");
+
+    use regex::Regex;
+    // .unwrap() is okay, because we should always get a correct regex (see `.unwrap_or()` calls above)
+    let yes_regex: Regex = Regex::new(yes_expr).unwrap();
+
+    io::stdout().flush()?;
+    let stdin = io::stdin();
+    let mut line = String::new();
+    stdin.read_line(&mut line)?;
+
+    if yes_regex.is_match(line.trim()) {
+        Ok(())
+    } else {
+        Err(io::Error::new(io::ErrorKind::Other, "Aborted"))
+    }
+}
+
 /// Define a simple CLI command.
 pub struct CliCommand {
     /// The Schema definition.
-- 
2.39.2