//! A [macro](crate::choice_type) to generate choice type
//! and generated choice types that has 2 to 15 variants,
//! which are named `Choice{i}`.

// TODO: peek to decide matched choice when possible.
/// Generate choice type.
///
/// ## Example
///
/// ```rust,ignore
/// pest3::choice_type!(Choice2, (Choice0, T0), (Choice1, T1));
/// ```
#[macro_export]
macro_rules! choice_type {
    ( $name:ident, $( ( $variant:ident, $type:ident, $getter:ident ) ),* $(,)? ) => {
        /// Choice type generated by `pest::choice_type!`.
        #[derive(Clone, Debug, Eq, Hash, PartialEq)]
        pub enum $name<$( $type ),*> {
            $(
                #[doc = ::core::stringify!(A choice for $type.)]
                $variant($type)
            ),*
        }
        impl<'i, R, $($type, )*>
        $crate::typed::TypedNode<'i, R> for $name<$($type, )*>
        where
            R: $crate::typed::RuleType,
            $(
                $type: $crate::typed::TypedNode<'i, R>,
            )*
        {
            #[inline]
            fn try_parse_with_partial(
                input: $crate::Position<'i>,
                stack: &mut $crate::Stack<$crate::Span<'i>>,
                tracker: &mut $crate::typed::Tracker<'i, R>,
            ) -> ::core::option::Option<($crate::Position<'i>, Self)> {
                $(
                    stack.snapshot();
                    match $type::try_parse_with_partial(input, stack, tracker) {
                        ::core::option::Option::Some((input, choice)) => {
                            stack.clear_snapshot();
                            let res = Self::$variant(choice);
                            return ::core::option::Option::Some((input, res))
                        }
                        ::core::option::Option::None => {
                            stack.restore();
                        }
                    }
                )*
                ::core::option::Option::None
            }
            #[inline]
            fn check_with_partial(
                input: $crate::Position<'i>,
                stack: &mut $crate::Stack<$crate::Span<'i>>,
                tracker: &mut $crate::typed::Tracker<'i, R>,
            ) -> ::core::option::Option<$crate::Position<'i>> {
                $(
                    stack.snapshot();
                    match $type::check_with_partial(input, stack, tracker) {
                        ::core::option::Option::Some(input) => {
                            stack.clear_snapshot();
                            return ::core::option::Option::Some(input)
                        }
                        ::core::option::Option::None => {
                            stack.restore();
                        }
                    }
                )*
                ::core::option::Option::None
            }
        }
        impl<'i, $($type, )*> $name<$($type, )*> {
            $(
                /// Try to get variant.
                pub fn $getter(&self) -> $crate::std::Option<&$type> {
                    match self {
                        Self::$variant(val) => $crate::std::Some(val),
                        _ => $crate::std::None,
                    }
                }
            )*
        }
        impl<R, $($type, )*>
        $crate::typed::PairContainer<R> for $name<$($type, )*>
        where
            $(
                $type: $crate::typed::PairContainer<R>,
            )*
        {
            fn for_each_child_pair(&self, f: &mut impl $crate::std::FnMut($crate::token::Pair<R>)) {
                match self {
                    $(
                        Self::$variant(variant) => variant.for_self_or_for_each_child_pair(f),
                    )*
                }
            }
        }
    };
}

choice_type! {
    Choice2,
    (Choice0, T0, choice_0),
    (Choice1, T1, choice_1)
}

choice_type! {
    Choice3,
    (Choice0, T0, choice_0),
    (Choice1, T1, choice_1),
    (Choice2, T2, choice_2)
}

choice_type! {
    Choice4,
    (Choice0, T0, choice_0),
    (Choice1, T1, choice_1),
    (Choice2, T2, choice_2),
    (Choice3, T3, choice_3)
}

choice_type! {
    Choice5,
    (Choice0, T0, choice_0),
    (Choice1, T1, choice_1),
    (Choice2, T2, choice_2),
    (Choice3, T3, choice_3),
    (Choice4, T4, choice_4)
}

choice_type! {
    Choice6,
    (Choice0, T0, choice_0),
    (Choice1, T1, choice_1),
    (Choice2, T2, choice_2),
    (Choice3, T3, choice_3),
    (Choice4, T4, choice_4),
    (Choice5, T5, choice_5)
}

choice_type! {
    Choice7,
    (Choice0, T0, choice_0),
    (Choice1, T1, choice_1),
    (Choice2, T2, choice_2),
    (Choice3, T3, choice_3),
    (Choice4, T4, choice_4),
    (Choice5, T5, choice_5),
    (Choice6, T6, choice_6)
}

choice_type! {
    Choice8,
    (Choice0, T0, choice_0),
    (Choice1, T1, choice_1),
    (Choice2, T2, choice_2),
    (Choice3, T3, choice_3),
    (Choice4, T4, choice_4),
    (Choice5, T5, choice_5),
    (Choice6, T6, choice_6),
    (Choice7, T7, choice_7)
}

choice_type! {
    Choice9,
    (Choice0, T0, choice_0),
    (Choice1, T1, choice_1),
    (Choice2, T2, choice_2),
    (Choice3, T3, choice_3),
    (Choice4, T4, choice_4),
    (Choice5, T5, choice_5),
    (Choice6, T6, choice_6),
    (Choice7, T7, choice_7),
    (Choice8, T8, choice_8)
}

choice_type! {
    Choice10,
    (Choice0, T0, choice_0),
    (Choice1, T1, choice_1),
    (Choice2, T2, choice_2),
    (Choice3, T3, choice_3),
    (Choice4, T4, choice_4),
    (Choice5, T5, choice_5),
    (Choice6, T6, choice_6),
    (Choice7, T7, choice_7),
    (Choice8, T8, choice_8),
    (Choice9, T9, choice_9)
}

choice_type! {
    Choice11,
    (Choice0,  T0,  choice_0 ),
    (Choice1,  T1,  choice_1 ),
    (Choice2,  T2,  choice_2 ),
    (Choice3,  T3,  choice_3 ),
    (Choice4,  T4,  choice_4 ),
    (Choice5,  T5,  choice_5 ),
    (Choice6,  T6,  choice_6 ),
    (Choice7,  T7,  choice_7 ),
    (Choice8,  T8,  choice_8 ),
    (Choice9,  T9,  choice_9 ),
    (Choice10, T10, choice_10)
}

choice_type! {
    Choice12,
    (Choice0,  T0,  choice_0 ),
    (Choice1,  T1,  choice_1 ),
    (Choice2,  T2,  choice_2 ),
    (Choice3,  T3,  choice_3 ),
    (Choice4,  T4,  choice_4 ),
    (Choice5,  T5,  choice_5 ),
    (Choice6,  T6,  choice_6 ),
    (Choice7,  T7,  choice_7 ),
    (Choice8,  T8,  choice_8 ),
    (Choice9,  T9,  choice_9 ),
    (Choice10, T10, choice_10),
    (Choice11, T11, choice_11)
}

choice_type! {
    Choice13,
    (Choice0,  T0,  choice_0 ),
    (Choice1,  T1,  choice_1 ),
    (Choice2,  T2,  choice_2 ),
    (Choice3,  T3,  choice_3 ),
    (Choice4,  T4,  choice_4 ),
    (Choice5,  T5,  choice_5 ),
    (Choice6,  T6,  choice_6 ),
    (Choice7,  T7,  choice_7 ),
    (Choice8,  T8,  choice_8 ),
    (Choice9,  T9,  choice_9 ),
    (Choice10, T10, choice_10),
    (Choice11, T11, choice_11),
    (Choice12, T12, choice_12)
}

choice_type! {
    Choice14,
    (Choice0,  T0,  choice_0 ),
    (Choice1,  T1,  choice_1 ),
    (Choice2,  T2,  choice_2 ),
    (Choice3,  T3,  choice_3 ),
    (Choice4,  T4,  choice_4 ),
    (Choice5,  T5,  choice_5 ),
    (Choice6,  T6,  choice_6 ),
    (Choice7,  T7,  choice_7 ),
    (Choice8,  T8,  choice_8 ),
    (Choice9,  T9,  choice_9 ),
    (Choice10, T10, choice_10),
    (Choice11, T11, choice_11),
    (Choice12, T12, choice_12),
    (Choice13, T13, choice_13),
}

choice_type! {
    Choice15,
    (Choice0,  T0,  choice_0 ),
    (Choice1,  T1,  choice_1 ),
    (Choice2,  T2,  choice_2 ),
    (Choice3,  T3,  choice_3 ),
    (Choice4,  T4,  choice_4 ),
    (Choice5,  T5,  choice_5 ),
    (Choice6,  T6,  choice_6 ),
    (Choice7,  T7,  choice_7 ),
    (Choice8,  T8,  choice_8 ),
    (Choice9,  T9,  choice_9 ),
    (Choice10, T10, choice_10),
    (Choice11, T11, choice_11),
    (Choice12, T12, choice_12),
    (Choice13, T13, choice_13),
    (Choice14, T14, choice_14),
}

choice_type! {
    Choice16,
    (Choice0,  T0,  choice_0 ),
    (Choice1,  T1,  choice_1 ),
    (Choice2,  T2,  choice_2 ),
    (Choice3,  T3,  choice_3 ),
    (Choice4,  T4,  choice_4 ),
    (Choice5,  T5,  choice_5 ),
    (Choice6,  T6,  choice_6 ),
    (Choice7,  T7,  choice_7 ),
    (Choice8,  T8,  choice_8 ),
    (Choice9,  T9,  choice_9 ),
    (Choice10, T10, choice_10),
    (Choice11, T11, choice_11),
    (Choice12, T12, choice_12),
    (Choice13, T13, choice_13),
    (Choice14, T14, choice_14),
    (Choice15, T15, choice_15),
}