extern crate byteorder;
#[macro_use]
extern crate crunchy;
extern crate rand;
#[cfg(feature = "rustc-serialize")]
extern crate rustc_serialize;

pub mod arith;
mod fields;
mod groups;

use fields::FieldElement;
use groups::{GroupElement, G1Params, G2Params, GroupParams};

use std::ops::{Add, Mul, Neg, Sub};
use rand::Rng;

#[derive(Copy, Clone, Debug, PartialEq, Eq)]
#[cfg_attr(feature = "rustc-serialize", derive(RustcDecodable, RustcEncodable))]
#[repr(C)]
pub struct Fr(fields::Fr);

impl Fr {
    pub fn zero() -> Self {
        Fr(fields::Fr::zero())
    }
    pub fn one() -> Self {
        Fr(fields::Fr::one())
    }
    pub fn random<R: Rng>(rng: &mut R) -> Self {
        Fr(fields::Fr::random(rng))
    }
    pub fn pow(&self, exp: Fr) -> Self {
        Fr(self.0.pow(exp.0))
    }
    pub fn from_str(s: &str) -> Option<Self> {
        fields::Fr::from_str(s).map(|e| Fr(e))
    }
    pub fn inverse(&self) -> Option<Self> {
        self.0.inverse().map(|e| Fr(e))
    }
    pub fn is_zero(&self) -> bool {
        self.0.is_zero()
    }
    pub fn interpret(buf: &[u8; 64]) -> Fr {
        Fr(fields::Fr::interpret(buf))
    }
    pub fn from_slice(slice: &[u8]) -> Result<Self, FieldError> {
        arith::U256::from_slice(slice)
            .map_err(|_| FieldError::InvalidSliceLength) // todo: maybe more sensful error handling
            .and_then(|x| fields::Fr::new_mul_factor(x).ok_or(FieldError::NotMember))
            .map(|x| Fr(x))
    }
    pub fn to_big_endian(&self, slice: &mut [u8]) -> Result<(), FieldError> {
        self.0
            .raw()
            .to_big_endian(slice)
            .map_err(|_| FieldError::InvalidSliceLength)
    }
}

impl Add<Fr> for Fr {
    type Output = Fr;

    fn add(self, other: Fr) -> Fr {
        Fr(self.0 + other.0)
    }
}

impl Sub<Fr> for Fr {
    type Output = Fr;

    fn sub(self, other: Fr) -> Fr {
        Fr(self.0 - other.0)
    }
}

impl Neg for Fr {
    type Output = Fr;

    fn neg(self) -> Fr {
        Fr(-self.0)
    }
}

impl Mul for Fr {
    type Output = Fr;

    fn mul(self, other: Fr) -> Fr {
        Fr(self.0 * other.0)
    }
}

#[derive(Debug)]
pub enum FieldError {
    InvalidSliceLength,
    NotMember,
}

pub use groups::Error as GroupError;

#[derive(Copy, Clone, Debug, PartialEq, Eq)]
#[cfg_attr(feature = "rustc-serialize", derive(RustcDecodable, RustcEncodable))]
#[repr(C)]
pub struct Fq(fields::Fq);

impl Fq {
    pub fn zero() -> Self {
        Fq(fields::Fq::zero())
    }
    pub fn one() -> Self {
        Fq(fields::Fq::one())
    }
    pub fn random<R: Rng>(rng: &mut R) -> Self {
        Fq(fields::Fq::random(rng))
    }
    pub fn pow(&self, exp: Fq) -> Self {
        Fq(self.0.pow(exp.0))
    }
    pub fn from_str(s: &str) -> Option<Self> {
        fields::Fq::from_str(s).map(|e| Fq(e))
    }
    pub fn inverse(&self) -> Option<Self> {
        self.0.inverse().map(|e| Fq(e))
    }
    pub fn is_zero(&self) -> bool {
        self.0.is_zero()
    }
    pub fn interpret(buf: &[u8; 64]) -> Fq {
        Fq(fields::Fq::interpret(buf))
    }
    pub fn from_slice(slice: &[u8]) -> Result<Self, FieldError> {
        arith::U256::from_slice(slice)
            .map_err(|_| FieldError::InvalidSliceLength) // todo: maybe more sensful error handling
            .and_then(|x| fields::Fq::new(x).ok_or(FieldError::NotMember))
            .map(|x| Fq(x))
    }
    pub fn to_big_endian(&self, slice: &mut [u8]) -> Result<(), FieldError> {
        let mut a: arith::U256 = self.0.into();
        // convert from Montgomery representation
        a.mul(
            &fields::Fq::one().raw(),
            &fields::Fq::modulus(),
            self.0.inv(),
        );
        a.to_big_endian(slice)
            .map_err(|_| FieldError::InvalidSliceLength)
    }
    pub fn from_u256(u256: arith::U256) -> Result<Self, FieldError> {
        Ok(Fq(fields::Fq::new(u256).ok_or(FieldError::NotMember)?))
    }
    pub fn into_u256(self) -> arith::U256 {
        (self.0).into()
    }
}

impl Add<Fq> for Fq {
    type Output = Fq;

    fn add(self, other: Fq) -> Fq {
        Fq(self.0 + other.0)
    }
}

impl Sub<Fq> for Fq {
    type Output = Fq;

    fn sub(self, other: Fq) -> Fq {
        Fq(self.0 - other.0)
    }
}

impl Neg for Fq {
    type Output = Fq;

    fn neg(self) -> Fq {
        Fq(-self.0)
    }
}

impl Mul for Fq {
    type Output = Fq;

    fn mul(self, other: Fq) -> Fq {
        Fq(self.0 * other.0)
    }
}

#[derive(Copy, Clone, Debug, PartialEq, Eq)]
#[repr(C)]
pub struct Fq2(fields::Fq2);

impl Fq2 {
    pub fn one() -> Fq2 {
        Fq2(fields::Fq2::one())
    }

    pub fn i() -> Fq2 {
        Fq2::new(Fq::zero(), Fq::one())
    }

    pub fn zero() -> Fq2 {
        Fq2(fields::Fq2::zero())
    }

    /// Initalizes new F_q2(a + bi, a is real coeff, b is imaginary)
    pub fn new(a: Fq, b: Fq) -> Fq2 {
        Fq2(fields::Fq2::new(a.0, b.0))
    }

    pub fn is_zero(&self) -> bool {
        self.0.is_zero()
    }

    pub fn pow(&self, exp: arith::U256) -> Self {
        Fq2(self.0.pow(exp))
    }

    pub fn real(&self) -> Fq {
        Fq(*self.0.real())
    }

    pub fn imaginary(&self) -> Fq {
        Fq(*self.0.imaginary())
    }
}


impl Add<Fq2> for Fq2 {
    type Output = Self;

    fn add(self, other: Self) -> Self {
        Fq2(self.0 + other.0)
    }
}

impl Sub<Fq2> for Fq2 {
    type Output = Self;

    fn sub(self, other: Self) -> Self {
        Fq2(self.0 - other.0)
    }
}

impl Neg for Fq2 {
    type Output = Self;

    fn neg(self) -> Self {
        Fq2(-self.0)
    }
}

impl Mul for Fq2 {
    type Output = Self;

    fn mul(self, other: Self) -> Self {
        Fq2(self.0 * other.0)
    }
}

pub trait Group
    : Send
    + Sync
    + Copy
    + Clone
    + PartialEq
    + Eq
    + Sized
    + Add<Self, Output = Self>
    + Sub<Self, Output = Self>
    + Neg<Output = Self>
    + Mul<Fr, Output = Self> {
    fn zero() -> Self;
    fn one() -> Self;
    fn random<R: Rng>(rng: &mut R) -> Self;
    fn is_zero(&self) -> bool;
    fn normalize(&mut self);
}

#[derive(Copy, Clone, PartialEq, Eq)]
#[cfg_attr(feature = "rustc-serialize", derive(RustcDecodable, RustcEncodable))]
#[repr(C)]
pub struct G1(groups::G1);

impl G1 {
    pub fn new(x: Fq, y: Fq, z: Fq) -> Self {
        G1(groups::G1::new(x.0, y.0, z.0))
    }

    pub fn x(&self) -> Fq {
        Fq(self.0.x().clone())
    }

    pub fn set_x(&mut self, x: Fq) {
        *self.0.x_mut() = x.0
    }

    pub fn y(&self) -> Fq {
        Fq(self.0.y().clone())
    }

    pub fn set_y(&mut self, y: Fq) {
        *self.0.y_mut() = y.0
    }

    pub fn z(&self) -> Fq {
        Fq(self.0.z().clone())
    }

    pub fn set_z(&mut self, z: Fq) {
        *self.0.z_mut() = z.0
    }

    pub fn b() -> Fq {
        Fq(G1Params::coeff_b())
    }
}

impl Group for G1 {
    fn zero() -> Self {
        G1(groups::G1::zero())
    }
    fn one() -> Self {
        G1(groups::G1::one())
    }
    fn random<R: Rng>(rng: &mut R) -> Self {
        G1(groups::G1::random(rng))
    }
    fn is_zero(&self) -> bool {
        self.0.is_zero()
    }
    fn normalize(&mut self) {
        let new = match self.0.to_affine() {
            Some(a) => a,
            None => return,
        };

        self.0 = new.to_jacobian();
    }
}

impl Add<G1> for G1 {
    type Output = G1;

    fn add(self, other: G1) -> G1 {
        G1(self.0 + other.0)
    }
}

impl Sub<G1> for G1 {
    type Output = G1;

    fn sub(self, other: G1) -> G1 {
        G1(self.0 - other.0)
    }
}

impl Neg for G1 {
    type Output = G1;

    fn neg(self) -> G1 {
        G1(-self.0)
    }
}

impl Mul<Fr> for G1 {
    type Output = G1;

    fn mul(self, other: Fr) -> G1 {
        G1(self.0 * other.0)
    }
}

#[derive(Copy, Clone, PartialEq, Eq)]
#[cfg_attr(feature = "rustc-serialize", derive(RustcDecodable, RustcEncodable))]
#[repr(C)]
pub struct AffineG1(groups::AffineG1);

impl AffineG1 {
    pub fn new(x: Fq, y: Fq) -> Result<Self, GroupError> {
        Ok(AffineG1(groups::AffineG1::new(x.0, y.0)?))
    }

    pub fn x(&self) -> Fq {
        Fq(self.0.x().clone())
    }

    pub fn set_x(&mut self, x: Fq) {
        *self.0.x_mut() = x.0
    }

    pub fn y(&self) -> Fq {
        Fq(self.0.y().clone())
    }

    pub fn set_y(&mut self, y: Fq) {
        *self.0.y_mut() = y.0
    }

    pub fn from_jacobian(g1: G1) -> Option<Self> {
        g1.0.to_affine().map(|x| AffineG1(x))
    }
}

impl From<AffineG1> for G1 {
    fn from(affine: AffineG1) -> Self {
        G1(affine.0.to_jacobian())
    }
}

#[derive(Copy, Clone, PartialEq, Eq)]
#[cfg_attr(feature = "rustc-serialize", derive(RustcDecodable, RustcEncodable))]
#[repr(C)]
pub struct G2(groups::G2);

impl G2 {
    pub fn new(x: Fq2, y: Fq2, z: Fq2) -> Self {
        G2(groups::G2::new(x.0, y.0, z.0))
    }

    pub fn x(&self) -> Fq2 {
        Fq2(self.0.x().clone())
    }

    pub fn set_x(&mut self, x: Fq2) {
        *self.0.x_mut() = x.0
    }

    pub fn y(&self) -> Fq2 {
        Fq2(self.0.y().clone())
    }

    pub fn set_y(&mut self, y: Fq2) {
        *self.0.y_mut() = y.0
    }

    pub fn z(&self) -> Fq2 {
        Fq2(self.0.z().clone())
    }

    pub fn set_z(&mut self, z: Fq2) {
        *self.0.z_mut() = z.0
    }

    pub fn b() -> Fq2 {
        Fq2(G2Params::coeff_b())
    }
}

impl Group for G2 {
    fn zero() -> Self {
        G2(groups::G2::zero())
    }
    fn one() -> Self {
        G2(groups::G2::one())
    }
    fn random<R: Rng>(rng: &mut R) -> Self {
        G2(groups::G2::random(rng))
    }
    fn is_zero(&self) -> bool {
        self.0.is_zero()
    }
    fn normalize(&mut self) {
        let new = match self.0.to_affine() {
            Some(a) => a,
            None => return,
        };

        self.0 = new.to_jacobian();
    }
}

impl Add<G2> for G2 {
    type Output = G2;

    fn add(self, other: G2) -> G2 {
        G2(self.0 + other.0)
    }
}

impl Sub<G2> for G2 {
    type Output = G2;

    fn sub(self, other: G2) -> G2 {
        G2(self.0 - other.0)
    }
}

impl Neg for G2 {
    type Output = G2;

    fn neg(self) -> G2 {
        G2(-self.0)
    }
}

impl Mul<Fr> for G2 {
    type Output = G2;

    fn mul(self, other: Fr) -> G2 {
        G2(self.0 * other.0)
    }
}

#[derive(Copy, Clone, PartialEq, Eq)]
#[repr(C)]
pub struct Gt(fields::Fq12);

impl Gt {
    pub fn one() -> Self {
        Gt(fields::Fq12::one())
    }
    pub fn pow(&self, exp: Fr) -> Self {
        Gt(self.0.pow(exp.0))
    }
    pub fn inverse(&self) -> Self {
        Gt(self.0.inverse().unwrap())
    }
}

impl Mul<Gt> for Gt {
    type Output = Gt;

    fn mul(self, other: Gt) -> Gt {
        Gt(self.0 * other.0)
    }
}

pub fn pairing(p: G1, q: G2) -> Gt {
    Gt(groups::pairing(&p.0, &q.0))
}

#[derive(Copy, Clone, PartialEq, Eq)]
#[cfg_attr(feature = "rustc-serialize", derive(RustcDecodable, RustcEncodable))]
#[repr(C)]
pub struct AffineG2(groups::AffineG2);

impl AffineG2 {
    pub fn new(x: Fq2, y: Fq2) -> Result<Self, GroupError> {
        Ok(AffineG2(groups::AffineG2::new(x.0, y.0)?))
    }

    pub fn x(&self) -> Fq2 {
        Fq2(self.0.x().clone())
    }

    pub fn set_x(&mut self, x: Fq2) {
        *self.0.x_mut() = x.0
    }

    pub fn y(&self) -> Fq2 {
        Fq2(self.0.y().clone())
    }

    pub fn set_y(&mut self, y: Fq2) {
        *self.0.y_mut() = y.0
    }

    pub fn from_jacobian(g2: G2) -> Option<Self> {
        g2.0.to_affine().map(|x| AffineG2(x))
    }
}

impl From<AffineG2> for G2 {
    fn from(affine: AffineG2) -> Self {
        G2(affine.0.to_jacobian())
    }
}