use poulpy_hal::{
    api::{VmpPMatAlloc, VmpPMatAllocBytes, VmpPrepare, VmpPrepareTmpBytes},
    layouts::{Backend, Data, DataMut, DataRef, Module, Scratch, VmpPMat, VmpPMatToRef, ZnxInfos},
    oep::VmpPMatAllocBytesImpl,
};

use crate::layouts::{
    Base2K, BuildError, Degree, Dnum, Dsize, GGSWCiphertext, GGSWInfos, GLWEInfos, LWEInfos, Rank, TorusPrecision,
    prepared::{Prepare, PrepareAlloc, PrepareScratchSpace},
};

#[derive(PartialEq, Eq)]
pub struct GGSWCiphertextPrepared<D: Data, B: Backend> {
    pub(crate) data: VmpPMat<D, B>,
    pub(crate) k: TorusPrecision,
    pub(crate) base2k: Base2K,
    pub(crate) dsize: Dsize,
}

impl<D: Data, B: Backend> LWEInfos for GGSWCiphertextPrepared<D, B> {
    fn n(&self) -> Degree {
        Degree(self.data.n() as u32)
    }

    fn base2k(&self) -> Base2K {
        self.base2k
    }

    fn k(&self) -> TorusPrecision {
        self.k
    }

    fn size(&self) -> usize {
        self.data.size()
    }
}

impl<D: Data, B: Backend> GLWEInfos for GGSWCiphertextPrepared<D, B> {
    fn rank(&self) -> Rank {
        Rank(self.data.cols_out() as u32 - 1)
    }
}

impl<D: Data, B: Backend> GGSWInfos for GGSWCiphertextPrepared<D, B> {
    fn dsize(&self) -> Dsize {
        self.dsize
    }

    fn dnum(&self) -> Dnum {
        Dnum(self.data.rows() as u32)
    }
}

pub struct GGSWCiphertextPreparedBuilder<D: Data, B: Backend> {
    data: Option<VmpPMat<D, B>>,
    base2k: Option<Base2K>,
    k: Option<TorusPrecision>,
    dsize: Option<Dsize>,
}

impl<D: Data, B: Backend> GGSWCiphertextPrepared<D, B> {
    #[inline]
    pub fn builder() -> GGSWCiphertextPreparedBuilder<D, B> {
        GGSWCiphertextPreparedBuilder {
            data: None,
            base2k: None,
            k: None,
            dsize: None,
        }
    }
}

impl<B: Backend> GGSWCiphertextPreparedBuilder<Vec<u8>, B> {
    #[inline]
    pub fn layout<A>(mut self, infos: &A) -> Self
    where
        A: GGSWInfos,
        B: VmpPMatAllocBytesImpl<B>,
    {
        debug_assert!(
            infos.size() as u32 > infos.dsize().0,
            "invalid ggsw: ceil(k/base2k): {} <= dsize: {}",
            infos.size(),
            infos.dsize()
        );

        assert!(
            infos.dnum().0 * infos.dsize().0 <= infos.size() as u32,
            "invalid ggsw: dnum: {} * dsize:{} > ceil(k/base2k): {}",
            infos.dnum(),
            infos.dsize(),
            infos.size(),
        );

        self.data = Some(VmpPMat::alloc(
            infos.n().into(),
            infos.dnum().into(),
            (infos.rank() + 1).into(),
            (infos.rank() + 1).into(),
            infos.size(),
        ));
        self.base2k = Some(infos.base2k());
        self.k = Some(infos.k());
        self.dsize = Some(infos.dsize());
        self
    }
}

impl<D: Data, B: Backend> GGSWCiphertextPreparedBuilder<D, B> {
    #[inline]
    pub fn data(mut self, data: VmpPMat<D, B>) -> Self {
        self.data = Some(data);
        self
    }
    #[inline]
    pub fn base2k(mut self, base2k: Base2K) -> Self {
        self.base2k = Some(base2k);
        self
    }
    #[inline]
    pub fn k(mut self, k: TorusPrecision) -> Self {
        self.k = Some(k);
        self
    }

    #[inline]
    pub fn dsize(mut self, dsize: Dsize) -> Self {
        self.dsize = Some(dsize);
        self
    }

    pub fn build(self) -> Result<GGSWCiphertextPrepared<D, B>, BuildError> {
        let data: VmpPMat<D, B> = self.data.ok_or(BuildError::MissingData)?;
        let base2k: Base2K = self.base2k.ok_or(BuildError::MissingBase2K)?;
        let k: TorusPrecision = self.k.ok_or(BuildError::MissingK)?;
        let dsize: Dsize = self.dsize.ok_or(BuildError::MissingDigits)?;

        if base2k == 0_u32 {
            return Err(BuildError::ZeroBase2K);
        }

        if dsize == 0_u32 {
            return Err(BuildError::ZeroBase2K);
        }

        if k == 0_u32 {
            return Err(BuildError::ZeroTorusPrecision);
        }

        if data.n() == 0 {
            return Err(BuildError::ZeroDegree);
        }

        if data.cols() == 0 {
            return Err(BuildError::ZeroCols);
        }

        if data.size() == 0 {
            return Err(BuildError::ZeroLimbs);
        }

        Ok(GGSWCiphertextPrepared {
            data,
            base2k,
            k,
            dsize,
        })
    }
}

impl<B: Backend> GGSWCiphertextPrepared<Vec<u8>, B> {
    pub fn alloc<A>(module: &Module<B>, infos: &A) -> Self
    where
        A: GGSWInfos,
        Module<B>: VmpPMatAlloc<B>,
    {
        Self::alloc_with(
            module,
            infos.base2k(),
            infos.k(),
            infos.dnum(),
            infos.dsize(),
            infos.rank(),
        )
    }

    pub fn alloc_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, dnum: Dnum, dsize: Dsize, rank: Rank) -> Self
    where
        Module<B>: VmpPMatAlloc<B>,
    {
        let size: usize = k.0.div_ceil(base2k.0) as usize;
        debug_assert!(
            size as u32 > dsize.0,
            "invalid ggsw: ceil(k/base2k): {size} <= dsize: {}",
            dsize.0
        );

        assert!(
            dnum.0 * dsize.0 <= size as u32,
            "invalid ggsw: dnum: {} * dsize:{} > ceil(k/base2k): {size}",
            dnum.0,
            dsize.0,
        );

        Self {
            data: module.vmp_pmat_alloc(
                dnum.into(),
                (rank + 1).into(),
                (rank + 1).into(),
                k.0.div_ceil(base2k.0) as usize,
            ),
            k,
            base2k,
            dsize,
        }
    }

    pub fn alloc_bytes<A>(module: &Module<B>, infos: &A) -> usize
    where
        A: GGSWInfos,
        Module<B>: VmpPMatAllocBytes,
    {
        Self::alloc_bytes_with(
            module,
            infos.base2k(),
            infos.k(),
            infos.dnum(),
            infos.dsize(),
            infos.rank(),
        )
    }

    pub fn alloc_bytes_with(module: &Module<B>, base2k: Base2K, k: TorusPrecision, dnum: Dnum, dsize: Dsize, rank: Rank) -> usize
    where
        Module<B>: VmpPMatAllocBytes,
    {
        let size: usize = k.0.div_ceil(base2k.0) as usize;
        debug_assert!(
            size as u32 > dsize.0,
            "invalid ggsw: ceil(k/base2k): {size} <= dsize: {}",
            dsize.0
        );

        assert!(
            dnum.0 * dsize.0 <= size as u32,
            "invalid ggsw: dnum: {} * dsize:{} > ceil(k/base2k): {size}",
            dnum.0,
            dsize.0,
        );

        module.vmp_pmat_alloc_bytes(dnum.into(), (rank + 1).into(), (rank + 1).into(), size)
    }
}

impl<D: DataRef, B: Backend> GGSWCiphertextPrepared<D, B> {
    pub fn data(&self) -> &VmpPMat<D, B> {
        &self.data
    }
}

impl<B: Backend, A: GGSWInfos> PrepareScratchSpace<B, A> for GGSWCiphertextPrepared<Vec<u8>, B>
where
    Module<B>: VmpPrepareTmpBytes,
{
    fn prepare_scratch_space(module: &Module<B>, infos: &A) -> usize {
        module.vmp_prepare_tmp_bytes(
            infos.dnum().into(),
            (infos.rank() + 1).into(),
            (infos.rank() + 1).into(),
            infos.size(),
        )
    }
}

impl<D: DataMut, DR: DataRef, B: Backend> Prepare<B, GGSWCiphertext<DR>> for GGSWCiphertextPrepared<D, B>
where
    Module<B>: VmpPrepare<B>,
{
    fn prepare(&mut self, module: &Module<B>, other: &GGSWCiphertext<DR>, scratch: &mut Scratch<B>) {
        module.vmp_prepare(&mut self.data, &other.data, scratch);
        self.k = other.k;
        self.base2k = other.base2k;
        self.dsize = other.dsize;
    }
}

impl<D: DataRef, B: Backend> PrepareAlloc<B, GGSWCiphertextPrepared<Vec<u8>, B>> for GGSWCiphertext<D>
where
    Module<B>: VmpPMatAlloc<B> + VmpPrepare<B>,
{
    fn prepare_alloc(&self, module: &Module<B>, scratch: &mut Scratch<B>) -> GGSWCiphertextPrepared<Vec<u8>, B> {
        let mut ggsw_prepared: GGSWCiphertextPrepared<Vec<u8>, B> = GGSWCiphertextPrepared::alloc(module, self);
        ggsw_prepared.prepare(module, self, scratch);
        ggsw_prepared
    }
}

pub trait GGSWCiphertextPreparedToRef<B: Backend> {
    fn to_ref(&self) -> GGSWCiphertextPrepared<&[u8], B>;
}

impl<D: DataRef, B: Backend> GGSWCiphertextPreparedToRef<B> for GGSWCiphertextPrepared<D, B> {
    fn to_ref(&self) -> GGSWCiphertextPrepared<&[u8], B> {
        GGSWCiphertextPrepared::builder()
            .base2k(self.base2k())
            .dsize(self.dsize())
            .k(self.k())
            .data(self.data.to_ref())
            .build()
            .unwrap()
    }
}