//! Juniper values conversion for GenericFraction
//! The format is case sensitive text representation of the sign and numbers.
//! Those are:
//! * Special cases: `NaN`, `+inf`, `-inf`
//! * Zero: `+0`, `-0`
//! * Whole numbers: `+1`, `-2`
//! * Fractions: `+1/2`, `-3/4`

use super::{GenericFraction, Sign};
use generic::GenericInteger;
use juniper::{ParseScalarResult, ParseScalarValue, Value};

impl<__S, T> ::juniper::GraphQLValueAsync<__S> for GenericFraction<T>
where
    Self: Sync,
    Self::TypeInfo: Sync,
    Self::Context: Sync,
    T: Clone + GenericInteger,
    __S: ::juniper::ScalarValue + Send + Sync,
{
    fn resolve_async<'a>(
        &'a self,
        info: &'a Self::TypeInfo,
        selection_set: Option<&'a [::juniper::Selection<__S>]>,
        executor: &'a ::juniper::Executor<Self::Context, __S>,
    ) -> ::juniper::BoxFuture<'a, ::juniper::ExecutionResult<__S>> {
        use juniper::futures::future;
        let v = ::juniper::GraphQLValue::resolve(self, info, selection_set, executor);
        Box::pin(future::ready(v))
    }
}
impl<S, T> ::juniper::marker::IsInputType<S> for GenericFraction<T>
where
    S: ::juniper::ScalarValue,
    T: Clone + GenericInteger,
{
}
impl<S, T> ::juniper::marker::IsOutputType<S> for GenericFraction<T>
where
    S: ::juniper::ScalarValue,
    T: Clone + GenericInteger,
{
}
impl<S, T> ::juniper::GraphQLType<S> for GenericFraction<T>
where
    S: ::juniper::ScalarValue,
    T: Clone + GenericInteger,
{
    fn name(_: &Self::TypeInfo) -> Option<&'static str> {
        Some("Fraction")
    }
    fn meta<'r>(
        info: &Self::TypeInfo,
        registry: &mut ::juniper::Registry<'r, S>,
    ) -> ::juniper::meta::MetaType<'r, S>
    where
        S: 'r,
    {
        registry
            .build_scalar_type::<Self>(info)
            .description("Fraction")
            .into_meta()
    }
}
impl<S, T> ::juniper::GraphQLValue<S> for GenericFraction<T>
where
    S: ::juniper::ScalarValue,
    T: Clone + GenericInteger,
{
    type Context = ();
    type TypeInfo = ();
    fn type_name<'__i>(&self, info: &'__i Self::TypeInfo) -> Option<&'__i str> {
        <Self as ::juniper::GraphQLType<S>>::name(info)
    }
    fn resolve(
        &self,
        _info: &(),
        _selection: Option<&[::juniper::Selection<S>]>,
        _executor: &::juniper::Executor<Self::Context, S>,
    ) -> ::juniper::ExecutionResult<S> {
        Ok(Value::scalar(self.to_string()))
    }
}
impl<S, T> ::juniper::ToInputValue<S> for GenericFraction<T>
where
    S: ::juniper::ScalarValue,
    T: Clone + GenericInteger,
{
    fn to_input_value(&self) -> ::juniper::InputValue<S> {
        ::juniper::ToInputValue::to_input_value(&format!("{:+}", self))
    }
}
impl<S, T> ::juniper::FromInputValue<S> for GenericFraction<T>
where
    S: ::juniper::ScalarValue,
    T: Clone + GenericInteger,
{
    fn from_input_value(value: &::juniper::InputValue<S>) -> Option<Self> {
        {
            let val = value.as_string_value()?;
            if val.len() < 2 {
                None
            } else if val == "NaN" {
                Some(GenericFraction::nan())
            } else if val == "-inf" {
                Some(GenericFraction::neg_infinity())
            } else if val == "+inf" {
                Some(GenericFraction::infinity())
            } else {
                let sign = match val.as_bytes()[0] {
                    43 => Sign::Plus,
                    45 => Sign::Minus,
                    _ => return None,
                };
                let (denom, split): (T, usize) = if let Some(idx) = val.find('/') {
                    let (_, denom) = val.split_at(idx + 1);
                    match T::from_str_radix(denom, 10) {
                        Ok(val) => (val, idx),
                        Err(_) => return None,
                    }
                } else {
                    (T::one(), val.len())
                };
                let (snum, _) = val.split_at(split);
                let (_, num) = snum.split_at(1);
                match T::from_str_radix(num, 10) {
                    Ok(num) => match sign {
                        Sign::Plus => Some(GenericFraction::new(num, denom)),
                        Sign::Minus => Some(GenericFraction::new_neg(num, denom)),
                    },
                    Err(_) => None,
                }
            }
        }
    }
}
impl<S, T> ::juniper::ParseScalarValue<S> for GenericFraction<T>
where
    S: ::juniper::ScalarValue,
    T: Clone + GenericInteger,
{
    fn from_str(value: ::juniper::parser::ScalarToken<'_>) -> ParseScalarResult<'_, S> {
        {
            <String as ParseScalarValue<S>>::from_str(value)
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use juniper::{FromInputValue, InputValue, ToInputValue};

    #[cfg(feature = "with-bigint")]
    use crate::BigFraction;

    type F = GenericFraction<u8>;
    fn get_tests() -> Vec<(&'static str, F)> {
        vec![
            ("NaN", F::nan()),
            ("-inf", F::neg_infinity()),
            ("+inf", F::infinity()),
            ("+0", F::new(0u8, 1u8)),
            ("-0", F::new_neg(0u8, 1u8)),
            ("+2", F::new(2u8, 1u8)),
            ("-2", F::new_neg(2u8, 1u8)),
            ("+1/2", F::new(1u8, 2u8)),
            ("-1/2", F::new_neg(1u8, 2u8)),
            ("+5/6", F::new(10u8, 12u8)),
            ("-1/255", F::new_neg(1u8, 255u8)),
        ]
    }

    #[cfg(feature = "with-bigint")]
    fn get_big_tests() -> Vec<(&'static str, BigFraction)> {
        use crate::Num;
        vec![
            ("NaN", BigFraction::nan()),
            ("-inf", BigFraction::neg_infinity()),
            ("+inf", BigFraction::infinity()),
            ("+0", BigFraction::new(0u8, 1u8)),
            ("-0", BigFraction::new_neg(0u8, 1u8)),
            ("+2", BigFraction::new(2u8, 1u8)),
            ("-2", BigFraction::new_neg(2u8, 1u8)),
            ("+1/2", BigFraction::new(1u8, 2u8)),
            ("-1/2", BigFraction::new_neg(1u8, 2u8)),
            ("+5/6", BigFraction::new(10u8, 12u8)),
            ("-1/255", BigFraction::new_neg(1u8, 255u8)),
            (
                "+42090291092428642826240949012091044820/42090291092428642826240949012091044821",
                BigFraction::from_str_radix(
                    "42090291092428642826240949012091044820/42090291092428642826240949012091044821",
                    10,
                )
                .unwrap(),
            ),
        ]
    }

    #[test]
    fn to_input_value() {
        for (s, v) in get_tests() {
            let value = <F as ToInputValue>::to_input_value(&v);
            let str_value = value.as_scalar_value::<String>();

            assert!(str_value.is_some());
            assert_eq!(s, str_value.unwrap());
        }

        #[cfg(feature = "with-bigint")]
        {
            for (s, v) in get_big_tests() {
                let value = <BigFraction as ToInputValue>::to_input_value(&v);
                let str_value = value.as_string_value();

                assert!(str_value.is_some());
                assert_eq!(s, str_value.unwrap());
            }
        }
    }

    #[test]
    fn from_input_value() {
        for (s, v) in get_tests() {
            let value = <F as FromInputValue>::from_input_value(&InputValue::scalar(s.to_owned()));
            assert_eq!(value, Some(v));
        }

        #[cfg(feature = "with-bigint")]
        {
            for (s, v) in get_big_tests() {
                let value =
                    <BigFraction as FromInputValue>::from_input_value(&InputValue::scalar(s));
                assert_eq!(value, Some(v));
            }
        }
    }
}
