use std::io::ErrorKind::NotFound;
use std::process::Command;

use crate::builtins::{execute_builtin, is_builtin};
use crate::error::ShellError;
use crate::parse::parse_line;

pub fn interpret(line: &str) -> Result<(), ShellError> {
    if line.is_empty() {
        return Err(ShellError::EmptyLine);
    }
    let (keyword, args) = parse_line(line);

    if is_builtin(keyword) {
        execute_builtin(keyword, &args)?;
    } else {
        let mut command = Command::new(keyword);
        command.args(args);

        execute(command)?;
    }

    Ok(())
}

fn execute(mut command: Command) -> Result<(), ShellError> {
    match command.spawn() {
        Ok(mut child) => {
            if let Err(err) = child.wait() {
                return Err(ShellError::ExecuteFailure(err.to_string()));
            }
            Ok(())
        }
        Err(err) => {
            if err.kind() == NotFound {
                return Err(ShellError::NotFound(command));
            }
            Err(ShellError::ExecuteFailure(err.to_string()))
        }
    }
}