//! Previously part of [`crate::rcore`].

use super::{cast::CastError, wrapped_origin::*, *};

type TypelessSerialize<'a> = dyn 'a + Fn(&mut dyn Serializer);

/// See [`Point::typeless`].
pub struct TypelessMentionable<'a, Ctx: Context<'a>> {
    t_serialize: Box<TypelessSerialize<'a>>,
    t_factory: TypelessFactory<'a, Ctx>,
    t_topology: Hash,
    t_points: Vec<Point<'a, Ctx, TypelessMentionable<'a, Ctx>>>,
}

type TypelessParsed<'a, Ctx> = Result<TypelessMentionable<'a, Ctx>, Box<dyn 'a + Error>>;

trait Tde<'a, Ctx: Context<'a>>: 'a + Send + Sync {
    fn clone_box(&self) -> TdeBox<'a, Ctx>;

    fn de<'c>(&self, demoted: Demoted<'a, 'c, Ctx>) -> TypelessParsed<'a, Ctx>
    where
        'a: 'c;
}

type TdeBox<'a, Ctx> = Box<dyn Tde<'a, Ctx>>;

trait Tut<'a, Ctx: Context<'a>>: 'a + Send + Sync {
    fn clone_box(&self) -> TutBox<'a, Ctx>;

    fn xt(
        &self,
        mentionable: TypelessMentionable<'a, Ctx>,
        tail: &[u8],
    ) -> Result<TypelessMentionable<'a, Ctx>, TypelessError<'a>>;
}

type TutBox<'a, Ctx> = Box<dyn Tut<'a, Ctx>>;

/// See [`Point::typeless`]/[`TypelessMentionable`].
pub struct TypelessFactory<'a, Ctx: Context<'a>> {
    t_deserialize: TdeBox<'a, Ctx>,
    t_extend: TutBox<'a, Ctx>,
}

impl<'a, Ctx: Context<'a>> Serializable for TypelessMentionable<'a, Ctx> {
    fn serialize(&self, serializer: &mut dyn Serializer) {
        (self.t_serialize)(serializer);
    }
}

impl<'a, Ctx: Context<'a>> MentionableBase<'a, Ctx> for TypelessMentionable<'a, Ctx> {
    type Fctr = TypelessFactory<'a, Ctx>;

    fn factory(&self) -> Self::Fctr {
        self.t_factory.clone()
    }
}

impl<'a, Ctx: Context<'a>> MentionableTop<'a, Ctx> for TypelessMentionable<'a, Ctx> {
    fn topology(&self) -> Hash {
        self.t_topology
    }

    fn points_typed(&self, points: &mut impl PointsVisitor<'a, Ctx>) {
        for point in self.t_points.iter() {
            points.visit(point)
        }
    }
}

impl<'a, Ctx: Context<'a>> Clone for TypelessFactory<'a, Ctx> {
    fn clone(&self) -> Self {
        Self {
            t_deserialize: self.t_deserialize.clone_box(),
            t_extend: self.t_extend.clone_box(),
        }
    }
}

/// See [`Point::typeless`]/[`TypelessFactory`].
#[derive(Debug)]
pub struct TypelessError<'a>(Box<dyn 'a + Error>);

impl<'a> Display for TypelessError<'a> {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "typeless error: {}", self.0)
    }
}

impl<'a> Error for TypelessError<'a> {}

impl<'a, Ctx: Context<'a>> FactoryBase<'a, Ctx> for TypelessFactory<'a, Ctx> {
    type Mtbl = TypelessMentionable<'a, Ctx>;

    type ParseError = TypelessError<'a>;
}

impl<'a, Ctx: Context<'a>> ParseMode for TypelessFactory<'a, Ctx> {
    type Mode = RegularMode;
}

impl<'a, Ctx: Context<'a>> RegularFactory<'a, Ctx> for TypelessFactory<'a, Ctx> {
    fn rdeserialize(&self, inctx: impl InCtx<'a, Ctx>) -> ParseResult<'a, Ctx, Self> {
        self.t_deserialize.de(inctx.demote()).map_err(TypelessError)
    }

    fn rextend(&self, mentionable: Self::Mtbl, tail: &[u8]) -> ParseResult<'a, Ctx, Self> {
        self.t_extend.xt(mentionable, tail)
    }
}

impl<'a, Ctx: Context<'a>> TypelessMentionable<'a, Ctx>
where
    Ctx::LookupError: From<CastError<'a>>,
{
    pub fn from_typed<A: Mentionable<'a, Ctx>>(mentionable: Rc<A>) -> Self {
        let factory = TypelessFactory::from_typed(mentionable.factory());
        let topology = mentionable.topology();
        let points = mentionable.points_vec();
        TypelessMentionable {
            t_serialize: Box::new(move |serializer| mentionable.serialize(serializer)),
            t_factory: factory,
            t_topology: topology,
            t_points: points,
        }
    }
}

impl<'a, Ctx: Context<'a>, F: Factory<'a, Ctx>> Tde<'a, Ctx> for F
where
    Ctx::LookupError: From<CastError<'a>>,
{
    fn clone_box(&self) -> TdeBox<'a, Ctx> {
        Box::new(self.clone())
    }

    fn de<'c>(&self, demoted: Demoted<'a, 'c, Ctx>) -> TypelessParsed<'a, Ctx>
    where
        'a: 'c,
    {
        self.deserialize(demoted)
            .map_err(|e| Box::new(e) as _)
            .map(Rc::new)
            .map(TypelessMentionable::from_typed)
    }
}

impl<'a, Ctx: Context<'a>, F: Factory<'a, Ctx>> Tut<'a, Ctx> for F
where
    Ctx::LookupError: From<CastError<'a>>,
{
    fn clone_box(&self) -> TutBox<'a, Ctx> {
        Box::new(self.clone())
    }

    fn xt(
        &self,
        mentionable: TypelessMentionable<'a, Ctx>,
        tail: &[u8],
    ) -> Result<TypelessMentionable<'a, Ctx>, TypelessError<'a>> {
        self.extend(
            match mentionable.cast(self.clone()) {
                Ok(m) => m,
                Err(e) => return Err(TypelessError::from_typed(e)),
            },
            tail,
        )
        .map_err(TypelessError::from_typed)
        .map(Rc::new)
        .map(TypelessMentionable::from_typed)
    }
}

impl<'a, Ctx: Context<'a>> TypelessFactory<'a, Ctx>
where
    Ctx::LookupError: From<CastError<'a>>,
{
    pub fn from_typed<F: Factory<'a, Ctx>>(factory: F) -> Self {
        TypelessFactory {
            t_deserialize: Box::new(factory.clone()),
            t_extend: Box::new(factory),
        }
    }
}

impl<'a> TypelessError<'a> {
    pub fn from_typed<E: 'a + Error>(error: E) -> Self {
        TypelessError(Box::new(error))
    }
}

impl<'a, Ctx: Context<'a>, A: Mentionable<'a, Ctx>> Point<'a, Ctx, A>
where
    Ctx::LookupError: From<CastError<'a>>,
{
    /// Typeless version of the point.
    pub fn typeless(&self) -> Point<'a, Ctx, TypelessMentionable<'a, Ctx>> {
        Point {
            point: self.point,
            origin: self.origin.clone().map(
                TypelessMentionable::from_typed,
                TypelessError::from_typed,
                TypelessFactory::from_typed,
            ),
        }
    }
}

pub trait MentionableExt<'a, Ctx: Context<'a>>: Mentionable<'a, Ctx> {
    /// References ([Point]s) to other objects. Typeless.
    fn points_typeless(&self, points: &mut Vec<Point<'a, Ctx, TypelessMentionable<'a, Ctx>>>);
    /// [Vec] of [Point]s as used by [`MentionableTop::topology`].
    fn points_vec(&self) -> Vec<Point<'a, Ctx, TypelessMentionable<'a, Ctx>>>;
}

impl<'a, Ctx: Context<'a>, A: Mentionable<'a, Ctx>> MentionableExt<'a, Ctx> for A
where
    Ctx::LookupError: From<CastError<'a>>,
{
    fn points_typeless(&self, points: &mut Vec<Point<'a, Ctx, TypelessMentionable<'a, Ctx>>>) {
        self.points_typed(points)
    }

    fn points_vec(&self) -> Vec<Point<'a, Ctx, TypelessMentionable<'a, Ctx>>> {
        let mut points = Vec::new();
        self.points_typeless(&mut points);
        points
    }
}

impl<'a, Ctx: Context<'a>> PointsVisitor<'a, Ctx>
    for Vec<Point<'a, Ctx, TypelessMentionable<'a, Ctx>>>
where
    Ctx::LookupError: From<CastError<'a>>,
{
    fn visit<A: Mentionable<'a, Ctx>>(&mut self, point: &Point<'a, Ctx, A>) {
        self.push(point.typeless());
    }
}