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use crate::{error::*, layout::MatrixLayout, *};
use cauchy::*;
use num_traits::Zero;

pub trait Rcond_: Scalar + Sized {
    /// Estimates the the reciprocal of the condition number of the matrix in 1-norm.
    ///
    /// `anorm` should be the 1-norm of the matrix `a`.
    fn rcond(l: MatrixLayout, a: &[Self], anorm: Self::Real) -> Result<Self::Real>;
}

macro_rules! impl_rcond_real {
    ($scalar:ty, $gecon:path) => {
        impl Rcond_ for $scalar {
            fn rcond(l: MatrixLayout, a: &[Self], anorm: Self::Real) -> Result<Self::Real> {
                let (n, _) = l.size();
                let mut rcond = Self::Real::zero();
                let mut info = 0;

                let mut work = unsafe { vec_uninit(4 * n as usize) };
                let mut iwork = unsafe { vec_uninit(n as usize) };
                let norm_type = match l {
                    MatrixLayout::C { .. } => NormType::Infinity,
                    MatrixLayout::F { .. } => NormType::One,
                } as u8;
                unsafe {
                    $gecon(
                        norm_type,
                        n,
                        a,
                        l.lda(),
                        anorm,
                        &mut rcond,
                        &mut work,
                        &mut iwork,
                        &mut info,
                    )
                };
                info.as_lapack_result()?;

                Ok(rcond)
            }
        }
    };
}

impl_rcond_real!(f32, lapack::sgecon);
impl_rcond_real!(f64, lapack::dgecon);

macro_rules! impl_rcond_complex {
    ($scalar:ty, $gecon:path) => {
        impl Rcond_ for $scalar {
            fn rcond(l: MatrixLayout, a: &[Self], anorm: Self::Real) -> Result<Self::Real> {
                let (n, _) = l.size();
                let mut rcond = Self::Real::zero();
                let mut info = 0;
                let mut work = unsafe { vec_uninit(2 * n as usize) };
                let mut rwork = unsafe { vec_uninit(2 * n as usize) };
                let norm_type = match l {
                    MatrixLayout::C { .. } => NormType::Infinity,
                    MatrixLayout::F { .. } => NormType::One,
                } as u8;
                unsafe {
                    $gecon(
                        norm_type,
                        n,
                        a,
                        l.lda(),
                        anorm,
                        &mut rcond,
                        &mut work,
                        &mut rwork,
                        &mut info,
                    )
                };
                info.as_lapack_result()?;

                Ok(rcond)
            }
        }
    };
}

impl_rcond_complex!(c32, lapack::cgecon);
impl_rcond_complex!(c64, lapack::zgecon);