use backend::hal::{
    api::{FillUniform, Reset},
    layouts::{Data, DataMut, DataRef, MatZnx, ReaderFrom, WriterTo},
};

use crate::layouts::{GGLWECiphertext, GLWECiphertext, Infos};
use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};

use std::fmt;

#[derive(PartialEq, Eq, Clone)]
pub struct GGLWESwitchingKey<D: Data> {
    pub(crate) key: GGLWECiphertext<D>,
    pub(crate) sk_in_n: usize,  // Degree of sk_in
    pub(crate) sk_out_n: usize, // Degree of sk_out
}

impl<D: DataRef> fmt::Debug for GGLWESwitchingKey<D> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{}", self)
    }
}

impl<D: DataRef> fmt::Display for GGLWESwitchingKey<D> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(
            f,
            "(GLWESwitchingKey: sk_in_n={} sk_out_n={}) {}",
            self.sk_in_n, self.sk_out_n, self.key.data
        )
    }
}

impl<D: DataMut> FillUniform for GGLWESwitchingKey<D> {
    fn fill_uniform(&mut self, source: &mut sampling::source::Source) {
        self.key.fill_uniform(source);
    }
}

impl<D: DataMut> Reset for GGLWESwitchingKey<D>
where
    MatZnx<D>: Reset,
{
    fn reset(&mut self) {
        self.key.reset();
        self.sk_in_n = 0;
        self.sk_out_n = 0;
    }
}

impl GGLWESwitchingKey<Vec<u8>> {
    pub fn alloc(n: usize, basek: usize, k: usize, rows: usize, digits: usize, rank_in: usize, rank_out: usize) -> Self {
        GGLWESwitchingKey {
            key: GGLWECiphertext::alloc(n, basek, k, rows, digits, rank_in, rank_out),
            sk_in_n: 0,
            sk_out_n: 0,
        }
    }

    pub fn bytes_of(n: usize, basek: usize, k: usize, rows: usize, digits: usize, rank_in: usize, rank_out: usize) -> usize {
        GGLWECiphertext::<Vec<u8>>::bytes_of(n, basek, k, rows, digits, rank_in, rank_out)
    }
}

impl<D: Data> Infos for GGLWESwitchingKey<D> {
    type Inner = MatZnx<D>;

    fn inner(&self) -> &Self::Inner {
        self.key.inner()
    }

    fn basek(&self) -> usize {
        self.key.basek()
    }

    fn k(&self) -> usize {
        self.key.k()
    }
}

impl<D: Data> GGLWESwitchingKey<D> {
    pub fn rank(&self) -> usize {
        self.key.data.cols_out() - 1
    }

    pub fn rank_in(&self) -> usize {
        self.key.data.cols_in()
    }

    pub fn rank_out(&self) -> usize {
        self.key.data.cols_out() - 1
    }

    pub fn digits(&self) -> usize {
        self.key.digits()
    }

    pub fn sk_degree_in(&self) -> usize {
        self.sk_in_n
    }

    pub fn sk_degree_out(&self) -> usize {
        self.sk_out_n
    }
}

impl<D: DataRef> GGLWESwitchingKey<D> {
    pub fn at(&self, row: usize, col: usize) -> GLWECiphertext<&[u8]> {
        self.key.at(row, col)
    }
}

impl<D: DataMut> GGLWESwitchingKey<D> {
    pub fn at_mut(&mut self, row: usize, col: usize) -> GLWECiphertext<&mut [u8]> {
        self.key.at_mut(row, col)
    }
}

impl<D: DataMut> ReaderFrom for GGLWESwitchingKey<D> {
    fn read_from<R: std::io::Read>(&mut self, reader: &mut R) -> std::io::Result<()> {
        self.sk_in_n = reader.read_u64::<LittleEndian>()? as usize;
        self.sk_out_n = reader.read_u64::<LittleEndian>()? as usize;
        self.key.read_from(reader)
    }
}

impl<D: DataRef> WriterTo for GGLWESwitchingKey<D> {
    fn write_to<W: std::io::Write>(&self, writer: &mut W) -> std::io::Result<()> {
        writer.write_u64::<LittleEndian>(self.sk_in_n as u64)?;
        writer.write_u64::<LittleEndian>(self.sk_out_n as u64)?;
        self.key.write_to(writer)
    }
}