use crate::transducer::InvalidValue;

/// An error that it is likely impossible to recover from. This error should only be created in
/// situations where attempts to recover have already been attempted and have failed. Error handling
/// should consist of attempting to alert another system for maintenance and attempting to shut down
/// any systems that depend on the correct functionality of the component having errors.
///
/// In many systems there can be a single function for handling any critical error as a critical
/// error always means everything needs to be stopped.
#[derive(Copy, Clone, Eq, PartialEq, Debug)]
pub enum CriticalError {
    /// Critical communication failed and retries are either impossible or also failed.
    Communication,
    InvalidValue(InvalidValue),
}

impl CriticalError {
    //TODO: Switch to using ! as the return type for the FnOnce and the entire function when the ! feature is stabilized
    pub fn emergency_procedure(self, procedure: impl FnOnce(CriticalError)) {
        procedure(self);
    }
}

/// [Result] where error type is [CriticalError].
pub trait CriticalErrResult: Copy {
    type Value: Copy;

    //TODO: Switch to using ! as the return type for the FnOnce when the ! feature is stabilized
    /// Execute emergency procedure in the event of a critical, the emergency procedure cannot
    /// return. It should usually terminate the program, potentially rebooting the device in some sort of recovery mode.
    fn err_emproc(self, procedure: impl FnOnce(CriticalError)) -> Self::Value;
}

impl<T: Copy> CriticalErrResult for Result<T, CriticalError> {
    type Value = T;

    //TODO: Switch to using ! as the return type for the FnOnce when the ! feature is stabilized
    fn err_emproc(self, procedure: impl FnOnce(CriticalError)) -> Self::Value {
        match self {
            Ok(val) => val,
            Err(error) => {
                error.emergency_procedure(procedure);
                //TODO: Remove this panic when we switch to ! return type
                panic!()
            },
        }
    }
}