//! # `argus-core`
//!
//! This crate provides some of the core functionality or interfaces for the other Argus
//! components. Mainly, the crate provides:
//!
//! 1. Expression tree nodes for defining temporal logic specifications (see [`expr`]).
//! 2. Different signal types for generating traces of data (see [`signals`]).
//! 3. A list of possible errors any component in Argus can generate (see
//!    [`enum@Error`]).

#![warn(missing_docs)]

pub mod expr;
pub mod prelude;
pub mod signals;

use std::time::Duration;

use thiserror::Error;

/// Errors generated by all Argus components.
#[derive(Error, Debug)]
pub enum Error {
    /// An identifier has been redeclared in a specification.
    ///
    /// This is called mainly from [`expr::ExprBuilder`].
    #[error("redeclaration of identifier")]
    IdentifierRedeclaration,

    /// An expression is provided with an insufficient number of arguments.
    ///
    /// This is called for N-ary expressions:
    /// [`NumExpr::Add`](crate::expr::NumExpr::Add),
    /// [`NumExpr::Mul`](crate::expr::NumExpr::Mul),
    /// [`BoolExpr::And`](crate::expr::BoolExpr::And), and
    /// [`BoolExpr::Or`](crate::expr::BoolExpr::Or).
    #[error("insufficient number of arguments")]
    IncompleteArgs,

    /// Attempting to `push` a new sample to a non-sampled signal
    /// ([`Signal::Empty`](crate::signals::Signal::Empty) or
    /// [`Signal::Constant`](crate::signals::Signal::Constant)).
    #[error("cannot push value to non-sampled signal")]
    InvalidPushToSignal,

    /// Pushing the new value to the sampled signal makes it not strictly monotonically
    /// increasing.
    #[error(
        "trying to create a non-monotonically signal, signal end time ({end_time:?}) > sample time point \
         ({current_sample:?})"
    )]
    NonMonotonicSignal {
        /// The time that the signal actually ends
        end_time: Duration,
        /// The time point of the new (erroneous) sample.
        current_sample: Duration,
    },

    /// Attempting to perform an invalid operation on a signal
    #[error("invalid operation on signal")]
    InvalidOperation,

    /// Attempting to index a signal not present in a trace (see
    /// [`mod@argus_semantics::Trace`].
    #[error("name not in signal trace")]
    SignalNotPresent,

    /// Attempting to perform a signal operation not supported by the type
    #[error("incorrect signal type")]
    InvalidSignalType,

    /// Incorrect cast of signal
    #[error("invalid cast from {from} to {to}")]
    InvalidCast {
        /// Type of the signal being cast from
        from: &'static str,
        /// Type of the signal being cast to
        to: &'static str,
    },
}

/// Alias for [`Error`](enum@Error)
pub type ArgusError = Error;
/// Alias for [`Result<T, ArgusError>`]
pub type ArgusResult<T> = Result<T, Error>;