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use super::super::{ComplexNumberSpace, Domain, DspVec, MetaData, ToSliceMut, Vector};
use crate::array_to_complex_mut;
use crate::multicore_support::*;
use crate::numbers::*;
use crate::simd_extensions::*;

/// Operations on complex types.
///
/// # Failures
///
/// If one of the methods is called on real data then `self.len()` will be set to `0`.
/// To avoid this it's recommended to use the `to_real_time_vec`, `to_real_freq_vec`
/// `to_complex_time_vec` and `to_complex_freq_vec` constructor methods since
/// the resulting types will already check at compile time (using the type system) that the
/// data is complex.
pub trait ComplexOps<T>
where
    T: RealNumber,
{
    /// Multiplies each vector element with `exp(j*(a*idx*self.delta() + b))`
    /// where `a` and `b` are arguments and `idx` is the index of the data points
    /// in the vector ranging from `0 to self.points() - 1`. `j` is the imaginary number and
    /// `exp` the exponential function.
    ///
    /// This method can be used to perform a frequency shift in time domain.
    ///
    /// # Example
    ///
    /// ```
    /// # use std::f64;
    /// # extern crate num_complex;
    /// # extern crate basic_dsp_vector;
    /// use basic_dsp_vector::*;
    /// # fn main() {
    /// let mut vector = vec!(1.0, 2.0, 3.0, 4.0).to_complex_time_vec();
    /// vector.multiply_complex_exponential(2.0, 3.0);
    /// let actual = &vector[..];
    /// let expected = &[-1.2722325, -1.838865, 4.6866837, -1.7421241];
    /// assert_eq!(actual.len(), expected.len());
    /// for i in 0..actual.len() {
    ///        assert!(f64::abs(actual[i] - expected[i]) < 1e-4);
    /// }
    /// # }
    /// ```
    fn multiply_complex_exponential(&mut self, a: T, b: T);

    /// Calculates the complex conjugate of the vector.
    /// # Example
    ///
    /// ```
    /// # extern crate num_complex;
    /// # extern crate basic_dsp_vector;
    /// use basic_dsp_vector::*;
    /// # fn main() {
    /// let mut vector = vec!(1.0, 2.0, 3.0, 4.0).to_complex_time_vec();
    /// vector.conj();
    /// assert_eq!([1.0, -2.0, 3.0, -4.0], vector[..]);
    /// # }
    /// ```
    fn conj(&mut self);
}

macro_rules! assert_complex {
    ($self_: ident) => {
        if !$self_.is_complex() {
            $self_.number_space.to_real();
            $self_.mark_vector_as_invalid();
        }
    };
}

impl<S, T, N, D> ComplexOps<T> for DspVec<S, T, N, D>
where
    S: ToSliceMut<T>,
    T: RealNumber,
    N: ComplexNumberSpace,
    D: Domain,
{
    fn multiply_complex_exponential(&mut self, a: T, b: T) {
        assert_complex!(self);
        let a = a * self.delta();
        let b = b * self.delta();
        let data_length = self.len();
        let array = self.data.to_slice_mut();
        Chunk::execute_with_range(
            Complexity::Small,
            &self.multicore_settings,
            &mut array[0..data_length],
            2,
            (a, b),
            move |array, range, args| {
                let (a, b) = args;
                let mut exponential = Complex::<T>::from_polar(&T::one(), &b)
                    * Complex::<T>::from_polar(&T::one(), &(a * T::from(range.start / 2).unwrap()));
                let increment = Complex::<T>::from_polar(&T::one(), &a);
                let array = array_to_complex_mut(array);
                for complex in array {
                    *complex = (*complex) * exponential;
                    exponential = exponential * increment;
                }
            },
        );
    }

    fn conj(&mut self) {
        assert_complex!(self);
        let factor = Complex::<T>::new(T::one(), -T::one());
        sel_reg!(self.simd_complex_operationf::<T>(
            |x, y| x * y,
            |x, _| x.conj(),
            factor,
            Complexity::Small
        ))
    }
}