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

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

pub trait GGLWEExecLayoutFamily<B: Backend> = VmpPMatAlloc<B> + VmpPMatAllocBytes + VmpPMatPrepare<B>;
use std::fmt;

#[derive(PartialEq, Eq, Clone)]
pub struct GGLWECiphertext<D: Data> {
    pub(crate) data: MatZnx<D>,
    pub(crate) basek: usize,
    pub(crate) k: usize,
    pub(crate) digits: usize,
}

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

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

impl<D: DataMut> Reset for GGLWECiphertext<D>
where
    MatZnx<D>: Reset,
{
    fn reset(&mut self) {
        self.data.reset();
        self.basek = 0;
        self.k = 0;
        self.digits = 0;
    }
}

impl<D: DataRef> fmt::Display for GGLWECiphertext<D> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(
            f,
            "(GGLWECiphertext: basek={} k={} digits={}) {}",
            self.basek, self.k, self.digits, self.data
        )
    }
}

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

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

impl GGLWECiphertext<Vec<u8>> {
    pub fn alloc(n: usize, basek: usize, k: usize, rows: usize, digits: usize, rank_in: usize, rank_out: usize) -> Self {
        let size: usize = k.div_ceil(basek);
        debug_assert!(
            size > digits,
            "invalid gglwe: ceil(k/basek): {} <= digits: {}",
            size,
            digits
        );

        assert!(
            rows * digits <= size,
            "invalid gglwe: rows: {} * digits:{} > ceil(k/basek): {}",
            rows,
            digits,
            size
        );

        Self {
            data: MatZnx::alloc(n, rows, rank_in, rank_out + 1, size),
            basek: basek,
            k,
            digits,
        }
    }

    pub fn bytes_of(n: usize, basek: usize, k: usize, rows: usize, digits: usize, rank_in: usize, rank_out: usize) -> usize {
        let size: usize = k.div_ceil(basek);
        debug_assert!(
            size > digits,
            "invalid gglwe: ceil(k/basek): {} <= digits: {}",
            size,
            digits
        );

        assert!(
            rows * digits <= size,
            "invalid gglwe: rows: {} * digits:{} > ceil(k/basek): {}",
            rows,
            digits,
            size
        );

        MatZnx::alloc_bytes(n, rows, rank_in, rank_out + 1, rows)
    }
}

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

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

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

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

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

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

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

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

impl<D: DataMut> ReaderFrom for GGLWECiphertext<D> {
    fn read_from<R: std::io::Read>(&mut self, reader: &mut R) -> std::io::Result<()> {
        self.k = reader.read_u64::<LittleEndian>()? as usize;
        self.basek = reader.read_u64::<LittleEndian>()? as usize;
        self.digits = reader.read_u64::<LittleEndian>()? as usize;
        self.data.read_from(reader)
    }
}

impl<D: DataRef> WriterTo for GGLWECiphertext<D> {
    fn write_to<W: std::io::Write>(&self, writer: &mut W) -> std::io::Result<()> {
        writer.write_u64::<LittleEndian>(self.k as u64)?;
        writer.write_u64::<LittleEndian>(self.basek as u64)?;
        writer.write_u64::<LittleEndian>(self.digits as u64)?;
        self.data.write_to(writer)
    }
}

#[derive(PartialEq, Eq, Clone)]
pub struct GLWESwitchingKey<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 GLWESwitchingKey<D> {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{}", self)
    }
}

impl<D: DataRef> fmt::Display for GLWESwitchingKey<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 GLWESwitchingKey<D> {
    fn fill_uniform(&mut self, source: &mut sampling::source::Source) {
        self.key.fill_uniform(source);
    }
}

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

impl GLWESwitchingKey<Vec<u8>> {
    pub fn alloc(n: usize, basek: usize, k: usize, rows: usize, digits: usize, rank_in: usize, rank_out: usize) -> Self {
        GLWESwitchingKey {
            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 GLWESwitchingKey<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> GLWESwitchingKey<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> GLWESwitchingKey<D> {
    pub fn at(&self, row: usize, col: usize) -> GLWECiphertext<&[u8]> {
        self.key.at(row, col)
    }
}

impl<D: DataMut> GLWESwitchingKey<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 GLWESwitchingKey<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 GLWESwitchingKey<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)
    }
}

#[derive(PartialEq, Eq, Clone)]
pub struct AutomorphismKey<D: Data> {
    pub(crate) key: GLWESwitchingKey<D>,
    pub(crate) p: i64,
}

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

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

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

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

impl AutomorphismKey<Vec<u8>> {
    pub fn alloc(n: usize, basek: usize, k: usize, rows: usize, digits: usize, rank: usize) -> Self {
        AutomorphismKey {
            key: GLWESwitchingKey::alloc(n, basek, k, rows, digits, rank, rank),
            p: 0,
        }
    }

    pub fn bytes_of(n: usize, basek: usize, k: usize, rows: usize, digits: usize, rank: usize) -> usize {
        GLWESwitchingKey::bytes_of(n, basek, k, rows, digits, rank, rank)
    }
}

impl<D: Data> Infos for AutomorphismKey<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> AutomorphismKey<D> {
    pub fn p(&self) -> i64 {
        self.p
    }

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

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

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

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

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

impl<D: DataMut> AutomorphismKey<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 AutomorphismKey<D> {
    fn read_from<R: std::io::Read>(&mut self, reader: &mut R) -> std::io::Result<()> {
        self.p = reader.read_u64::<LittleEndian>()? as i64;
        self.key.read_from(reader)
    }
}

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

#[derive(PartialEq, Eq, Clone)]
pub struct GLWETensorKey<D: Data> {
    pub(crate) keys: Vec<GLWESwitchingKey<D>>,
}

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

impl<D: DataMut> FillUniform for GLWETensorKey<D> {
    fn fill_uniform(&mut self, source: &mut sampling::source::Source) {
        self.keys
            .iter_mut()
            .for_each(|key: &mut GLWESwitchingKey<D>| key.fill_uniform(source))
    }
}

impl<D: DataMut> Reset for GLWETensorKey<D>
where
    MatZnx<D>: Reset,
{
    fn reset(&mut self) {
        self.keys
            .iter_mut()
            .for_each(|key: &mut GLWESwitchingKey<D>| key.reset())
    }
}

impl<D: DataRef> fmt::Display for GLWETensorKey<D> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        writeln!(f, "(GLWETensorKey)",)?;
        for (i, key) in self.keys.iter().enumerate() {
            write!(f, "{}: {}", i, key)?;
        }
        Ok(())
    }
}

impl GLWETensorKey<Vec<u8>> {
    pub fn alloc(n: usize, basek: usize, k: usize, rows: usize, digits: usize, rank: usize) -> Self {
        let mut keys: Vec<GLWESwitchingKey<Vec<u8>>> = Vec::new();
        let pairs: usize = (((rank + 1) * rank) >> 1).max(1);
        (0..pairs).for_each(|_| {
            keys.push(GLWESwitchingKey::alloc(n, basek, k, rows, digits, 1, rank));
        });
        Self { keys: keys }
    }

    pub fn bytes_of(n: usize, basek: usize, k: usize, rows: usize, digits: usize, rank: usize) -> usize {
        let pairs: usize = (((rank + 1) * rank) >> 1).max(1);
        pairs * GLWESwitchingKey::<Vec<u8>>::bytes_of(n, basek, k, rows, digits, 1, rank)
    }
}

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

    fn inner(&self) -> &Self::Inner {
        &self.keys[0].inner()
    }

    fn basek(&self) -> usize {
        self.keys[0].basek()
    }

    fn k(&self) -> usize {
        self.keys[0].k()
    }
}

impl<D: Data> GLWETensorKey<D> {
    pub fn rank(&self) -> usize {
        self.keys[0].rank()
    }

    pub fn rank_in(&self) -> usize {
        self.keys[0].rank_in()
    }

    pub fn rank_out(&self) -> usize {
        self.keys[0].rank_out()
    }

    pub fn digits(&self) -> usize {
        self.keys[0].digits()
    }
}

impl<D: DataMut> GLWETensorKey<D> {
    // Returns a mutable reference to GLWESwitchingKey_{s}(s[i] * s[j])
    pub fn at_mut(&mut self, mut i: usize, mut j: usize) -> &mut GLWESwitchingKey<D> {
        if i > j {
            std::mem::swap(&mut i, &mut j);
        };
        let rank: usize = self.rank();
        &mut self.keys[i * rank + j - (i * (i + 1) / 2)]
    }
}

impl<D: DataRef> GLWETensorKey<D> {
    // Returns a reference to GLWESwitchingKey_{s}(s[i] * s[j])
    pub fn at(&self, mut i: usize, mut j: usize) -> &GLWESwitchingKey<D> {
        if i > j {
            std::mem::swap(&mut i, &mut j);
        };
        let rank: usize = self.rank();
        &self.keys[i * rank + j - (i * (i + 1) / 2)]
    }
}

impl<D: DataMut> ReaderFrom for GLWETensorKey<D> {
    fn read_from<R: std::io::Read>(&mut self, reader: &mut R) -> std::io::Result<()> {
        let len: usize = reader.read_u64::<LittleEndian>()? as usize;
        if self.keys.len() != len {
            return Err(std::io::Error::new(
                std::io::ErrorKind::InvalidData,
                format!("self.keys.len()={} != read len={}", self.keys.len(), len),
            ));
        }
        for key in &mut self.keys {
            key.read_from(reader)?;
        }
        Ok(())
    }
}

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