//! The convert module.
//!
//! Contains implementations of `std::convert::From`
//! for Matrix and Vector types.

use std::convert::From;

use super::matrix::{Matrix, MatrixSlice, MatrixSliceMut, BaseMatrix};
use super::vector::Vector;


impl<T> From<Vector<T>> for Matrix<T> {
    fn from(vector: Vector<T>) -> Self {
        Matrix::new(vector.size(), 1, vector.into_vec())
    }
}

macro_rules! impl_matrix_from {
    ($slice_type:ident) => {
        impl<'a, T: Copy> From<$slice_type<'a, T>> for Matrix<T> {
            fn from(slice: $slice_type<'a, T>) -> Self {
                slice.iter_rows().collect::<Matrix<T>>()
            }
        }
    }
}

impl_matrix_from!(MatrixSlice);
impl_matrix_from!(MatrixSliceMut);


#[cfg(test)]
mod tests {
    use matrix::{Matrix, MatrixSlice, MatrixSliceMut, BaseMatrix};
    use vector::Vector;

    #[test]
    fn inner_product_as_matrix_multiplication() {
        let u: Vector<f32> = Vector::new(vec![1., 2., 3.]);
        let v: Vector<f32> = Vector::new(vec![3., 4., 5.]);
        let dot_product = u.dot(&v);

        let um: Matrix<f32> = u.into();
        let vm: Matrix<f32> = v.into();
        let matrix_product = um.transpose() * vm;

        assert_eq!(dot_product, matrix_product.data()[0]);
    }

    #[test]
    fn matrix_from_slice() {
        let mut a = Matrix::new(3, 3, vec![2.0; 9]);

        {
            let b = MatrixSlice::from_matrix(&a, [1, 1], 2, 2);
            let c = Matrix::from(b);
            assert_eq!(c.rows(), 2);
            assert_eq!(c.cols(), 2);
        }

        let d = MatrixSliceMut::from_matrix(&mut a, [1, 1], 2, 2);
        let e = Matrix::from(d);
        assert_eq!(e.rows(), 2);
        assert_eq!(e.cols(), 2);
    }

}