use clap::{crate_version, Arg, ArgAction, Command};
use std::env;
use uucore::{error::UResult, format_usage, help_about, help_usage};
const ABOUT: &str = help_about!("printenv.md");
const USAGE: &str = help_usage!("printenv.md");
static OPT_NULL: &str = "null";
static ARG_VARIABLES: &str = "variables";
#[uucore::main]
pub fn uumain(args: impl uucore::Args) -> UResult<()> {
let matches = uu_app().get_matches_from(args);
let variables: Vec<String> = matches
.get_many::<String>(ARG_VARIABLES)
.map(|v| v.map(ToString::to_string).collect())
.unwrap_or_default();
let separator = if matches.get_flag(OPT_NULL) {
"\x00"
} else {
"\n"
};
if variables.is_empty() {
for (env_var, value) in env::vars() {
print!("{env_var}={value}{separator}");
}
return Ok(());
}
let mut error_found = false;
for env_var in variables {
if env_var.contains('=') {
error_found = true;
continue;
}
if let Ok(var) = env::var(env_var) {
print!("{var}{separator}");
} else {
error_found = true;
}
}
if error_found {
Err(1.into())
} else {
Ok(())
}
}
pub fn uu_app() -> Command {
Command::new(uucore::util_name())
.version(crate_version!())
.about(ABOUT)
.override_usage(format_usage(USAGE))
.infer_long_args(true)
.arg(
Arg::new(OPT_NULL)
.short('0')
.long(OPT_NULL)
.help("end each output line with 0 byte rather than newline")
.action(ArgAction::SetTrue),
)
.arg(
Arg::new(ARG_VARIABLES)
.action(ArgAction::Append)
.num_args(1..),
)
}