//! Pair implementation based on [`StaticPair`].

use std::error::Error;
use std::fmt::Display;

use crate::atomic::*;
use crate::mode::*;
use crate::rcore::*;
use crate::rstd::inlining::static_pair::*;
use crate::rstd::inlining::*;

pub type PairObject<A, B> = StaticPairObject<(A, B)>;
pub type PairFactory<'a, Ctx, A, B> = StaticPairFactory<'a, Ctx, (A, B)>;

impl<A: Serializable, B: Serializable> StaticPairSerializable for (A, B) {
    type SA = A;
    type SB = B;

    fn elements(&self) -> (&Self::SA, &Self::SB) {
        (&self.0, &self.1)
    }

    fn into_elements(self) -> (Self::SA, Self::SB) {
        self
    }
}

#[derive(Debug)]
pub enum PairParseError<ErrorA: Error, ErrorB: Error> {
    A(ErrorA),
    B(ErrorB),
}

impl<ErrorA: Error, ErrorB: Error> Display for PairParseError<ErrorA, ErrorB> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            Self::A(error) => {
                write!(f, "error while parsing first element of a pair: {}", error)
            }
            Self::B(error) => {
                write!(f, "error while parsing second element of a pair: {}", error)
            }
        }
    }
}

impl<ErrorA: Error, ErrorB: Error> Error for PairParseError<ErrorA, ErrorB> {}

impl<'a, Ctx: Context<'a>, A: MentionableBase<'a, Ctx>, B: MentionableBase<'a, Ctx>>
    StaticPair<'a, Ctx> for (A, B)
where
    A::Fctr: ParseMode,
    B::Fctr: ParseMode,
{
    type FactoryData = (Self::FA, Self::FB);
    type A = A;
    type B = B;
    type FA = A::Fctr;
    type FB = B::Fctr;
    type ParseError = PairParseError<ParseError<'a, Ctx, A::Fctr>, ParseError<'a, Ctx, B::Fctr>>;

    fn factories(factory_data: &Self::FactoryData) -> (&Self::FA, &Self::FB) {
        (&factory_data.0, &factory_data.1)
    }

    fn from_parsed(
        _factory_data: &Self::FactoryData,
        a: Self::A,
        b: Self::B,
    ) -> Result<Self, Self::ParseError> {
        Ok((a, b))
    }

    fn from_error_a(
        _factory_data: &Self::FactoryData,
        error: ParseError<'a, Ctx, Self::FA>,
    ) -> Self::ParseError {
        PairParseError::A(error)
    }

    fn from_error_b(
        _factory_data: &Self::FactoryData,
        error: ParseError<'a, Ctx, Self::FB>,
    ) -> Self::ParseError {
        PairParseError::B(error)
    }

    fn factory_data(&self) -> Self::FactoryData {
        (self.0.factory(), self.1.factory())
    }
}

impl<A: AtomicBase + ParseMode, B: AtomicBase + ParseMode> StaticPairAtomic for (A, B) {
    type A = A;
    type B = B;

    type AParseError = PairParseError<A::AParseError, B::AParseError>;

    fn from_parsed(a: Self::A, b: Self::B) -> Result<Self, Self::AParseError> {
        Ok((a, b))
    }

    fn from_error_a(error: AParseError<Self::A>) -> Self::AParseError {
        PairParseError::A(error)
    }

    fn from_error_b(error: AParseError<Self::B>) -> Self::AParseError {
        PairParseError::B(error)
    }
}

impl<A: Serializable, B: Serializable> Serializable for (A, B) {
    fn serialize(&self, serializer: &mut dyn Serializer) {
        StaticPairObject::<Self>::serialize_sp(self, serializer)
    }
}

impl<'a, Ctx: Context<'a>, A: MentionableBase<'a, Ctx>, B: MentionableBase<'a, Ctx>>
    MentionableBase<'a, Ctx> for (A, B)
{
    type Fctr = (A::Fctr, B::Fctr);

    fn factory(&self) -> Self::Fctr {
        (self.0.factory(), self.1.factory())
    }
}

impl<'a, Ctx: Context<'a>, FA: FactoryBase<'a, Ctx>, FB: FactoryBase<'a, Ctx>> FactoryBase<'a, Ctx>
    for (FA, FB)
{
    type Mtbl = (FA::Mtbl, FB::Mtbl);

    type ParseError = PairParseError<FA::ParseError, FB::ParseError>;
}

impl<A: AtomicBase, B: AtomicBase> AtomicBase for (A, B) {
    type AParseError = PairParseError<A::AParseError, B::AParseError>;
}

impl<A, B: ParseMode> ParseMode for (A, B) {
    type Mode = B::Mode;
}

type PFImpl<'a, Ctx, FA, FB> = StaticPairFactory<
    'a,
    Ctx,
    (
        <FA as FactoryBase<'a, Ctx>>::Mtbl,
        <FB as FactoryBase<'a, Ctx>>::Mtbl,
    ),
>;

impl<'a, Ctx: Context<'a>, FA: InliningFactory<'a, Ctx>, FB: FactoryModeParse<'a, Ctx>>
    FactoryModeParse<'a, Ctx> for (FA, FB)
{
    fn mdeserialize<I: InCtx<'a, Ctx>>(&self, inctx: I) -> ModeResultM<'a, Ctx, Self, I> {
        PFImpl::<'a, Ctx, FA, FB>::mdeserialize_sp(self, inctx)
    }

    fn mextend(
        &self,
        mentionable: ExtensionSourceM<'a, Ctx, Self>,
        tail: &[u8],
    ) -> ExtensionResultM<'a, Ctx, Self> {
        PFImpl::<'a, Ctx, FA, FB>::mextend_sp(self, mentionable, tail)
    }
}

impl<'a, Ctx: Context<'a>, A: Mentionable<'a, Ctx>, B: Mentionable<'a, Ctx>> MentionableTop<'a, Ctx>
    for (A, B)
{
    fn points_typed(&self, points: &mut impl PointsVisitor<'a, Ctx>) {
        StaticPairObject::<Self>::points_typed_sp(self, points)
    }
}

impl<'a, Ctx: Context<'a>, FA, FB> FixedSizeFactory<'a, Ctx> for (FA, FB)
where
    FA: FixedSizeFactory<'a, Ctx>,
    FB: FixedSizeFactory<'a, Ctx> + FactoryModeParse<'a, Ctx>,
{
    fn size(&self) -> usize {
        self.0.size() + self.1.size()
    }
}

impl<A: InliningAtomic, B: AtomicModeParse> AtomicModeParse for (A, B) {
    fn ma_deserialize<I: Stream>(stream: I) -> AModeResultM<Self, I> {
        StaticPairObject::<Self>::ma_deserialize_sp(stream)
    }

    fn ma_extend(atomic: AExtensionSourceM<Self>, tail: &[u8]) -> AExtensionResultM<Self> {
        StaticPairObject::<Self>::ma_extend_sp(atomic, tail)
    }
}