#[cfg(not(PyPy))]
use crate::instance::PyNativeType;
use crate::{ffi, AsPyPointer, PyAny, Python};
#[cfg(not(PyPy))]
use std::ops::*;
use std::os::raw::c_double;

/// Represents a Python `complex`.
#[repr(transparent)]
pub struct PyComplex(PyAny);

pyobject_native_type!(
    PyComplex,
    ffi::PyComplexObject,
    ffi::PyComplex_Type,
    ffi::PyComplex_Check
);

impl PyComplex {
    /// Creates a new Python `complex` object, from its real and imaginary values.
    pub fn from_doubles(py: Python, real: c_double, imag: c_double) -> &PyComplex {
        unsafe {
            let ptr = ffi::PyComplex_FromDoubles(real, imag);
            py.from_owned_ptr(ptr)
        }
    }
    /// Returns the real part of the complex number.
    pub fn real(&self) -> c_double {
        unsafe { ffi::PyComplex_RealAsDouble(self.as_ptr()) }
    }
    /// Returns the imaginary part the complex number.
    pub fn imag(&self) -> c_double {
        unsafe { ffi::PyComplex_ImagAsDouble(self.as_ptr()) }
    }
    /// Returns `|self|`.
    #[cfg(not(Py_LIMITED_API))]
    #[cfg(not(PyPy))]
    pub fn abs(&self) -> c_double {
        unsafe {
            let val = (*(self.as_ptr() as *mut ffi::PyComplexObject)).cval;
            ffi::_Py_c_abs(val)
        }
    }
    /// Returns `self ** other`
    #[cfg(not(Py_LIMITED_API))]
    #[cfg(not(PyPy))]
    pub fn pow(&self, other: &PyComplex) -> &PyComplex {
        unsafe {
            self.py()
                .from_owned_ptr(complex_operation(self, other, ffi::_Py_c_pow))
        }
    }
}

#[cfg(not(Py_LIMITED_API))]
#[cfg(not(PyPy))]
#[inline(always)]
unsafe fn complex_operation(
    l: &PyComplex,
    r: &PyComplex,
    operation: unsafe extern "C" fn(ffi::Py_complex, ffi::Py_complex) -> ffi::Py_complex,
) -> *mut ffi::PyObject {
    let l_val = (*(l.as_ptr() as *mut ffi::PyComplexObject)).cval;
    let r_val = (*(r.as_ptr() as *mut ffi::PyComplexObject)).cval;
    ffi::PyComplex_FromCComplex(operation(l_val, r_val))
}

#[cfg(not(Py_LIMITED_API))]
#[cfg(not(PyPy))]
impl<'py> Add for &'py PyComplex {
    type Output = &'py PyComplex;
    fn add(self, other: &'py PyComplex) -> &'py PyComplex {
        unsafe {
            self.py()
                .from_owned_ptr(complex_operation(self, other, ffi::_Py_c_sum))
        }
    }
}

#[cfg(not(Py_LIMITED_API))]
#[cfg(not(PyPy))]
impl<'py> Sub for &'py PyComplex {
    type Output = &'py PyComplex;
    fn sub(self, other: &'py PyComplex) -> &'py PyComplex {
        unsafe {
            self.py()
                .from_owned_ptr(complex_operation(self, other, ffi::_Py_c_diff))
        }
    }
}

#[cfg(not(Py_LIMITED_API))]
#[cfg(not(PyPy))]
impl<'py> Mul for &'py PyComplex {
    type Output = &'py PyComplex;
    fn mul(self, other: &'py PyComplex) -> &'py PyComplex {
        unsafe {
            self.py()
                .from_owned_ptr(complex_operation(self, other, ffi::_Py_c_prod))
        }
    }
}

#[cfg(not(Py_LIMITED_API))]
#[cfg(not(PyPy))]
impl<'py> Div for &'py PyComplex {
    type Output = &'py PyComplex;
    fn div(self, other: &'py PyComplex) -> &'py PyComplex {
        unsafe {
            self.py()
                .from_owned_ptr(complex_operation(self, other, ffi::_Py_c_quot))
        }
    }
}

#[cfg(not(Py_LIMITED_API))]
#[cfg(not(PyPy))]
impl<'py> Neg for &'py PyComplex {
    type Output = &'py PyComplex;
    fn neg(self) -> &'py PyComplex {
        unsafe {
            let val = (*(self.as_ptr() as *mut ffi::PyComplexObject)).cval;
            self.py()
                .from_owned_ptr(ffi::PyComplex_FromCComplex(ffi::_Py_c_neg(val)))
        }
    }
}

#[cfg(feature = "num-complex")]
mod complex_conversion {
    use super::*;
    use crate::{FromPyObject, PyAny, PyErr, PyObject, PyResult, ToPyObject};
    use num_complex::Complex;

    impl PyComplex {
        /// Creates a new Python `PyComplex` object from num_complex::Complex.
        pub fn from_complex<'py, F: Into<c_double>>(
            py: Python<'py>,
            complex: Complex<F>,
        ) -> &'py PyComplex {
            unsafe {
                let ptr = ffi::PyComplex_FromDoubles(complex.re.into(), complex.im.into());
                py.from_owned_ptr(ptr)
            }
        }
    }
    macro_rules! complex_conversion {
        ($float: ty) => {
            impl ToPyObject for Complex<$float> {
                #[inline]
                fn to_object(&self, py: Python) -> PyObject {
                    crate::IntoPy::<PyObject>::into_py(self.to_owned(), py)
                }
            }
            impl crate::IntoPy<PyObject> for Complex<$float> {
                fn into_py(self, py: Python) -> PyObject {
                    unsafe {
                        let raw_obj =
                            ffi::PyComplex_FromDoubles(self.re as c_double, self.im as c_double);
                        PyObject::from_owned_ptr_or_panic(py, raw_obj)
                    }
                }
            }
            #[cfg(not(Py_LIMITED_API))]
            #[allow(clippy::float_cmp)] // The comparison is for an error value
            impl<'source> FromPyObject<'source> for Complex<$float> {
                fn extract(obj: &'source PyAny) -> PyResult<Complex<$float>> {
                    unsafe {
                        let val = ffi::PyComplex_AsCComplex(obj.as_ptr());
                        if val.real == -1.0 && PyErr::occurred(obj.py()) {
                            Err(PyErr::fetch(obj.py()))
                        } else {
                            Ok(Complex::new(val.real as $float, val.imag as $float))
                        }
                    }
                }
            }
            #[cfg(Py_LIMITED_API)]
            #[allow(clippy::float_cmp)] // The comparison is for an error value
            impl<'source> FromPyObject<'source> for Complex<$float> {
                fn extract(obj: &'source PyAny) -> PyResult<Complex<$float>> {
                    unsafe {
                        let ptr = obj.as_ptr();
                        let real = ffi::PyComplex_RealAsDouble(ptr);
                        if real == -1.0 && PyErr::occurred(obj.py()) {
                            return Err(PyErr::fetch(obj.py()));
                        }
                        let imag = ffi::PyComplex_ImagAsDouble(ptr);
                        Ok(Complex::new(real as $float, imag as $float))
                    }
                }
            }
        };
    }
    complex_conversion!(f32);
    complex_conversion!(f64);

    #[allow(clippy::float_cmp)] // The test wants to ensure that no precision was lost on the Python round-trip
    #[test]
    fn from_complex() {
        let gil = Python::acquire_gil();
        let py = gil.python();
        let complex = Complex::new(3.0, 1.2);
        let py_c = PyComplex::from_complex(py, complex);
        assert_eq!(py_c.real(), 3.0);
        assert_eq!(py_c.imag(), 1.2);
    }
    #[test]
    fn to_from_complex() {
        let gil = Python::acquire_gil();
        let py = gil.python();
        let val = Complex::new(3.0, 1.2);
        let obj = val.to_object(py);
        assert_eq!(obj.extract::<Complex<f64>>(py).unwrap(), val);
    }
    #[test]
    fn from_complex_err() {
        let gil = Python::acquire_gil();
        let py = gil.python();
        let obj = vec![1].to_object(py);
        assert!(obj.extract::<Complex<f64>>(py).is_err());
    }
}

#[cfg(test)]
mod test {
    use super::PyComplex;
    use crate::Python;
    use assert_approx_eq::assert_approx_eq;

    #[test]
    fn test_from_double() {
        use assert_approx_eq::assert_approx_eq;

        let gil = Python::acquire_gil();
        let py = gil.python();
        let complex = PyComplex::from_doubles(py, 3.0, 1.2);
        assert_approx_eq!(complex.real(), 3.0);
        assert_approx_eq!(complex.imag(), 1.2);
    }

    #[cfg(not(Py_LIMITED_API))]
    #[test]
    fn test_add() {
        let gil = Python::acquire_gil();
        let py = gil.python();
        let l = PyComplex::from_doubles(py, 3.0, 1.2);
        let r = PyComplex::from_doubles(py, 1.0, 2.6);
        let res = l + r;
        assert_approx_eq!(res.real(), 4.0);
        assert_approx_eq!(res.imag(), 3.8);
    }

    #[cfg(not(Py_LIMITED_API))]
    #[test]
    fn test_sub() {
        let gil = Python::acquire_gil();
        let py = gil.python();
        let l = PyComplex::from_doubles(py, 3.0, 1.2);
        let r = PyComplex::from_doubles(py, 1.0, 2.6);
        let res = l - r;
        assert_approx_eq!(res.real(), 2.0);
        assert_approx_eq!(res.imag(), -1.4);
    }

    #[cfg(not(Py_LIMITED_API))]
    #[test]
    fn test_mul() {
        let gil = Python::acquire_gil();
        let py = gil.python();
        let l = PyComplex::from_doubles(py, 3.0, 1.2);
        let r = PyComplex::from_doubles(py, 1.0, 2.6);
        let res = l * r;
        assert_approx_eq!(res.real(), -0.12);
        assert_approx_eq!(res.imag(), 9.0);
    }

    #[cfg(not(Py_LIMITED_API))]
    #[test]
    fn test_div() {
        let gil = Python::acquire_gil();
        let py = gil.python();
        let l = PyComplex::from_doubles(py, 3.0, 1.2);
        let r = PyComplex::from_doubles(py, 1.0, 2.6);
        let res = l / r;
        assert_approx_eq!(res.real(), 0.788_659_793_814_432_9);
        assert_approx_eq!(res.imag(), -0.850_515_463_917_525_7);
    }

    #[cfg(not(Py_LIMITED_API))]
    #[test]
    fn test_neg() {
        let gil = Python::acquire_gil();
        let py = gil.python();
        let val = PyComplex::from_doubles(py, 3.0, 1.2);
        let res = -val;
        assert_approx_eq!(res.real(), -3.0);
        assert_approx_eq!(res.imag(), -1.2);
    }

    #[cfg(not(Py_LIMITED_API))]
    #[test]
    fn test_abs() {
        let gil = Python::acquire_gil();
        let py = gil.python();
        let val = PyComplex::from_doubles(py, 3.0, 1.2);
        assert_approx_eq!(val.abs(), 3.231_098_884_280_702_2);
    }

    #[cfg(not(Py_LIMITED_API))]
    #[test]
    fn test_pow() {
        let gil = Python::acquire_gil();
        let py = gil.python();
        let l = PyComplex::from_doubles(py, 3.0, 1.2);
        let r = PyComplex::from_doubles(py, 1.2, 2.6);
        let val = l.pow(r);
        assert_approx_eq!(val.real(), -1.419_309_997_016_603_7);
        assert_approx_eq!(val.imag(), -0.541_297_466_033_544_6);
    }
}