use std::any::type_name;
use std::fmt::Debug;
use std::marker::Tuple;

use crate::interfaces::any_factory::{AnyFactory, AnyThreadsafeFactory};
use crate::interfaces::factory::IThreadsafeFactory;
use crate::ptr::TransientPtr;

pub struct ThreadsafeCastableFactory<Args, ReturnInterface>
where
    Args: Tuple + 'static,
    ReturnInterface: 'static + ?Sized,
{
    func: &'static (dyn Fn<Args, Output = TransientPtr<ReturnInterface>> + Send + Sync),
}

impl<Args, ReturnInterface> ThreadsafeCastableFactory<Args, ReturnInterface>
where
    Args: Tuple + 'static,
    ReturnInterface: 'static + ?Sized,
{
    pub fn new(
        func: &'static (dyn Fn<Args, Output = TransientPtr<ReturnInterface>>
                      + Send
                      + Sync),
    ) -> Self
    {
        Self { func }
    }
}

impl<Args, ReturnInterface> IThreadsafeFactory<Args, ReturnInterface>
    for ThreadsafeCastableFactory<Args, ReturnInterface>
where
    Args: Tuple + 'static,
    ReturnInterface: 'static + ?Sized,
{
}

impl<Args, ReturnInterface> Fn<Args> for ThreadsafeCastableFactory<Args, ReturnInterface>
where
    Args: Tuple + 'static,
    ReturnInterface: 'static + ?Sized,
{
    extern "rust-call" fn call(&self, args: Args) -> Self::Output
    {
        self.func.call(args)
    }
}

impl<Args, ReturnInterface> FnMut<Args>
    for ThreadsafeCastableFactory<Args, ReturnInterface>
where
    Args: Tuple + 'static,
    ReturnInterface: 'static + ?Sized,
{
    extern "rust-call" fn call_mut(&mut self, args: Args) -> Self::Output
    {
        self.call(args)
    }
}

impl<Args, ReturnInterface> FnOnce<Args>
    for ThreadsafeCastableFactory<Args, ReturnInterface>
where
    Args: Tuple + 'static,
    ReturnInterface: 'static + ?Sized,
{
    type Output = TransientPtr<ReturnInterface>;

    extern "rust-call" fn call_once(self, args: Args) -> Self::Output
    {
        self.call(args)
    }
}

impl<Args, ReturnInterface> AnyFactory
    for ThreadsafeCastableFactory<Args, ReturnInterface>
where
    Args: Tuple + 'static,
    ReturnInterface: 'static + ?Sized,
{
}

impl<Args, ReturnInterface> AnyThreadsafeFactory
    for ThreadsafeCastableFactory<Args, ReturnInterface>
where
    Args: Tuple + 'static,
    ReturnInterface: 'static + ?Sized,
{
}

impl<Args, ReturnInterface> Debug for ThreadsafeCastableFactory<Args, ReturnInterface>
where
    Args: Tuple + 'static,
    ReturnInterface: 'static + ?Sized,
{
    #[cfg(not(tarpaulin_include))]
    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result
    {
        let mut args = type_name::<Args>();

        if args.len() < 2 {
            return Err(std::fmt::Error::default());
        }

        args = args
            .get(1..args.len() - 1)
            .map_or_else(|| Err(std::fmt::Error::default()), Ok)?;

        if args.ends_with(',') {
            args = args
                .get(..args.len() - 1)
                .map_or_else(|| Err(std::fmt::Error), Ok)?;
        }

        let ret = type_name::<TransientPtr<ReturnInterface>>();

        formatter.write_fmt(format_args!(
            "ThreadsafeCastableFactory ({}) -> {}",
            args, ret
        ))
    }
}

#[cfg(test)]
mod tests
{
    use super::*;

    #[derive(Debug, PartialEq, Eq)]
    struct Bacon
    {
        heal_amount: u32,
    }

    #[test]
    fn can_call()
    {
        let castable_factory = ThreadsafeCastableFactory::new(&|heal_amount| {
            TransientPtr::new(Bacon { heal_amount })
        });

        let output = castable_factory.call((27,));

        assert_eq!(output, TransientPtr::new(Bacon { heal_amount: 27 }));
    }

    #[test]
    fn can_call_mut()
    {
        let mut castable_factory = ThreadsafeCastableFactory::new(&|heal_amount| {
            TransientPtr::new(Bacon { heal_amount })
        });

        let output = castable_factory.call_mut((1092,));

        assert_eq!(output, TransientPtr::new(Bacon { heal_amount: 1092 }));
    }

    #[test]
    fn can_call_once()
    {
        let castable_factory = ThreadsafeCastableFactory::new(&|heal_amount| {
            TransientPtr::new(Bacon { heal_amount })
        });

        let output = castable_factory.call_once((547,));

        assert_eq!(output, TransientPtr::new(Bacon { heal_amount: 547 }));
    }
}