use turkos_os_process_lifecycle_owners::spawn;
pub const ABI_HEADER: [u8; 8] = *b"TRTABI2\0";
pub struct Executable<'a> {
    recipe: spawn::Recipe<'a>,
    required: u64,
}
impl<'a> Executable<'a> {
    /// Pure immutable image preflight, before any PID/resource acquisition.
    /// available comes from the trusted kernel ABI observation, not the user.
    pub fn new(
        image: spawn::TrustedImage<'a>,
        argv: &[&[u8]],
        env: &[&[u8]],
        available: u64,
    ) -> Result<Self, spawn::Error> {
        let recipe = spawn::Recipe::new(image, argv, env)?;
        let mut header = [0u8; 16];
        for (i, b) in header.iter_mut().enumerate() {
            *b = recipe.expected_byte(spawn::Kind::Data, i)?;
        }
        if header[..8] != ABI_HEADER {
            return Err(spawn::Error::Image);
        }
        let required = u64::from_le_bytes(header[8..].try_into().unwrap());
        turkos_os_user_runtime_abi::compatible(required, available)
            .map_err(|_| spawn::Error::Image)?;
        Ok(Self { recipe, required })
    }
    pub fn required(&self) -> u64 {
        self.required
    }
    pub fn into_recipe(self) -> spawn::Recipe<'a> {
        self.recipe
    }
}