// Platform helpers to ease future no_std portability.
// The crate currently depends on `std`, but concentrating platform-specific
// pieces here makes migration simpler.

#[cfg(feature = "std")]
pub use std::sync::Arc;

#[cfg(feature = "std")]
pub fn run_parallel<L, R, OutL, OutR>(left: L, right: R) -> (OutL, OutR)
where
    L: FnOnce() -> OutL + Send + 'static,
    R: FnOnce() -> OutR + Send + 'static,
    OutL: Send + 'static,
    OutR: Send + 'static,
{
    let h1 = std::thread::spawn(left);
    let h2 = std::thread::spawn(right);
    (h1.join().unwrap(), h2.join().unwrap())
}

#[cfg(not(feature = "std"))]
mod no_std_support {
    extern crate alloc;
    pub use alloc::sync::Arc;

    pub fn run_parallel<L, R, OutL, OutR>(left: L, right: R) -> (OutL, OutR)
    where
        L: FnOnce() -> OutL + Send + 'static,
        R: FnOnce() -> OutR + Send + 'static,
        OutL: Send + 'static,
        OutR: Send + 'static,
    {
        // No threads available: fall back to sequential execution.
        (left(), right())
    }
}

#[cfg(not(feature = "std"))]
pub use no_std_support::*;