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use super::build::*;
use super::{build::CompareOp, Resolvable};
use crate::entity::EntityID;
use crate::{entity::EntityColumn, model::Modelable, Entity, QueryInterface};
use std::hash::{Hash, Hasher};
use std::marker::PhantomData;

/// Any query that can have a WHERE clause attached to it
pub trait Filterable<'r, 'q>: Resolvable<'r, 'q>
where
    'q: 'r,
{
    type Table: Entity;
    type Output;

    fn by<C: EntityColumn<Entity = Self::Table>, G: Modelable + ?Sized>(
        self,
        col: C,
        given: &'r G,
    ) -> Filter<'r, 'q, Self, C, G>
    where
        Self: Sized,
    {
        Filter {
            wrap: self,
            col,
            op: CompareOp::Equals,
            given,
            _ghost: PhantomData,
        }
    }

    fn by_id<I: EntityID<Entity = Self::Table>>(
        self,
        given: &'r I,
    ) -> Filter<'r, 'q, Self, <Self::Table as Entity>::IDColumn, I>
    where
        Self: Sized,
    {
        Filter {
            wrap: self,
            col: Self::Table::id_column(),
            op: CompareOp::Equals,
            given,
            _ghost: PhantomData,
        }
    }

    fn by_op<C: EntityColumn<Entity = Self::Table>, G: Modelable + ?Sized>(
        self,
        col: C,
        op: CompareOp,
        given: &'r G,
    ) -> Filter<'r, 'q, Self, C, G>
    where
        Self: Sized,
    {
        Filter {
            wrap: self,
            col,
            op,
            given,
            _ghost: PhantomData,
        }
    }
}

/// A concrete WHERE clause
pub struct Filter<'r, 'q, F: Filterable<'r, 'q>, C: EntityColumn, G: Modelable + ?Sized>
where
    'q: 'r,
{
    wrap: F,
    col: C,
    op: CompareOp,
    given: &'r G,
    _ghost: PhantomData<&'q ()>,
}

impl<'r, 'q, F: Filterable<'r, 'q>, C: EntityColumn, G: Modelable + ?Sized> StaticVersion
    for Filter<'r, 'q, F, C, G>
where
    <F as StaticVersion>::Is: Filterable<'static, 'static>,
{
    type Is = Filter<'static, 'static, <F as StaticVersion>::Is, C, u64>;
}

impl<'r, 'q, F: Filterable<'r, 'q>, C: EntityColumn, G: Modelable + ?Sized> QueryComponent
    for Filter<'r, 'q, F, C, G>
where
    <F as StaticVersion>::Is: Filterable<'static, 'static>,
    'q: 'r,
{
    fn derive(&self) -> DerivedQuery {
        self.wrap.derive().add(
            QueryPart::Where,
            format!("`{}` {} ?", self.col.name(), self.op.ch()),
        )
    }

    fn contribute<H: Hasher>(&self, hasher: &mut H) {
        self.wrap.contribute(hasher);
        std::any::TypeId::of::<Self::Is>().hash(hasher);
        std::any::TypeId::of::<C>().hash(hasher);
    }

    fn bind(&self, stmt: &mut sqlite::Statement<'_>) -> Result<usize, crate::Error> {
        let next_index = self.wrap.bind(stmt)?;

        self.given.bind_to(stmt, next_index)?;

        Ok(next_index + 1)
    }
}

impl<'r, 'q, O, F: Filterable<'r, 'q, Output = O>, C: EntityColumn, G: Modelable + ?Sized>
    Resolvable<'r, 'q> for Filter<'r, 'q, F, C, G>
where
    <F as StaticVersion>::Is: Filterable<'static, 'static>,
    'q: 'r,
{
    type Output = O;

    fn qi(&self) -> &'r QueryInterface<'q> {
        self.wrap.qi()
    }
}

impl<'r, 'q, O, F: Filterable<'r, 'q, Output = O>, C: EntityColumn, G: Modelable + ?Sized>
    Filterable<'r, 'q> for Filter<'r, 'q, F, C, G>
where
    <F as StaticVersion>::Is: Filterable<'static, 'static>,
    'q: 'r,
{
    type Output = O;
    type Table = C::Entity;
}