use num_complex::Complex64;
use num_traits::ToPrimitive;

use crate::function::{OptionalArg, PyFuncArgs};
use crate::pyobject::{PyContext, PyObjectRef, PyRef, PyResult, PyValue, TypeProtocol};
use crate::vm::VirtualMachine;

use super::objfloat;
use super::objint;
use super::objtype::{self, PyClassRef};

#[derive(Debug, Copy, Clone, PartialEq)]
pub struct PyComplex {
    value: Complex64,
}
type PyComplexRef = PyRef<PyComplex>;

impl PyValue for PyComplex {
    fn class(vm: &mut VirtualMachine) -> PyObjectRef {
        vm.ctx.complex_type()
    }
}

impl From<Complex64> for PyComplex {
    fn from(value: Complex64) -> Self {
        PyComplex { value }
    }
}

pub fn init(context: &PyContext) {
    let complex_type = &context.complex_type;

    let complex_doc =
        "Create a complex number from a real part and an optional imaginary part.\n\n\
         This is equivalent to (real + imag*1j) where imag defaults to 0.";

    context.set_attr(&complex_type, "__abs__", context.new_rustfunc(complex_abs));
    context.set_attr(&complex_type, "__add__", context.new_rustfunc(complex_add));
    context.set_attr(
        &complex_type,
        "__radd__",
        context.new_rustfunc(complex_radd),
    );
    context.set_attr(&complex_type, "__eq__", context.new_rustfunc(complex_eq));
    context.set_attr(&complex_type, "__neg__", context.new_rustfunc(complex_neg));
    context.set_attr(&complex_type, "__new__", context.new_rustfunc(complex_new));
    context.set_attr(&complex_type, "real", context.new_property(complex_real));
    context.set_attr(&complex_type, "imag", context.new_property(complex_imag));
    context.set_attr(
        &complex_type,
        "__doc__",
        context.new_str(complex_doc.to_string()),
    );
    context.set_attr(
        &complex_type,
        "__repr__",
        context.new_rustfunc(complex_repr),
    );
    context.set_attr(
        &complex_type,
        "conjugate",
        context.new_rustfunc(complex_conjugate),
    );
}

pub fn get_value(obj: &PyObjectRef) -> Complex64 {
    obj.payload::<PyComplex>().unwrap().value
}

fn complex_new(
    cls: PyClassRef,
    real: OptionalArg<PyObjectRef>,
    imag: OptionalArg<PyObjectRef>,
    vm: &mut VirtualMachine,
) -> PyResult<PyComplexRef> {
    let real = match real {
        OptionalArg::Missing => 0.0,
        OptionalArg::Present(ref value) => objfloat::make_float(vm, value)?,
    };

    let imag = match imag {
        OptionalArg::Missing => 0.0,
        OptionalArg::Present(ref value) => objfloat::make_float(vm, value)?,
    };

    let value = Complex64::new(real, imag);
    PyComplex { value }.into_ref_with_type(vm, cls)
}

fn complex_real(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
    arg_check!(vm, args, required = [(zelf, Some(vm.ctx.complex_type()))]);
    let Complex64 { re, .. } = get_value(zelf);
    Ok(vm.ctx.new_float(re))
}

fn complex_imag(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
    arg_check!(vm, args, required = [(zelf, Some(vm.ctx.complex_type()))]);
    let Complex64 { im, .. } = get_value(zelf);
    Ok(vm.ctx.new_float(im))
}

fn complex_abs(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
    arg_check!(vm, args, required = [(zelf, Some(vm.ctx.complex_type()))]);

    let Complex64 { re, im } = get_value(zelf);
    Ok(vm.ctx.new_float(re.hypot(im)))
}

fn complex_add(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
    arg_check!(
        vm,
        args,
        required = [(i, Some(vm.ctx.complex_type())), (i2, None)]
    );

    let v1 = get_value(i);
    if objtype::isinstance(i2, &vm.ctx.complex_type()) {
        Ok(vm.ctx.new_complex(v1 + get_value(i2)))
    } else if objtype::isinstance(i2, &vm.ctx.int_type()) {
        Ok(vm.ctx.new_complex(Complex64::new(
            v1.re + objint::get_value(i2).to_f64().unwrap(),
            v1.im,
        )))
    } else {
        Err(vm.new_type_error(format!("Cannot add {} and {}", i, i2)))
    }
}

fn complex_radd(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
    arg_check!(
        vm,
        args,
        required = [(i, Some(vm.ctx.complex_type())), (i2, None)]
    );

    let v1 = get_value(i);

    if objtype::isinstance(i2, &vm.ctx.int_type()) {
        Ok(vm.ctx.new_complex(Complex64::new(
            v1.re + objint::get_value(i2).to_f64().unwrap(),
            v1.im,
        )))
    } else {
        Err(vm.new_type_error(format!("Cannot add {} and {}", i, i2)))
    }
}

fn complex_conjugate(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
    arg_check!(vm, args, required = [(i, Some(vm.ctx.complex_type()))]);

    let v1 = get_value(i);
    Ok(vm.ctx.new_complex(v1.conj()))
}

fn complex_eq(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
    arg_check!(
        vm,
        args,
        required = [(zelf, Some(vm.ctx.complex_type())), (other, None)]
    );

    let z = get_value(zelf);

    let result = if objtype::isinstance(other, &vm.ctx.complex_type()) {
        z == get_value(other)
    } else if objtype::isinstance(other, &vm.ctx.int_type()) {
        match objint::get_value(other).to_f64() {
            Some(f) => z.im == 0.0f64 && z.re == f,
            None => false,
        }
    } else if objtype::isinstance(other, &vm.ctx.float_type()) {
        z.im == 0.0 && z.re == objfloat::get_value(other)
    } else {
        return Ok(vm.ctx.not_implemented());
    };

    Ok(vm.ctx.new_bool(result))
}

fn complex_neg(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
    arg_check!(vm, args, required = [(zelf, Some(vm.ctx.complex_type()))]);
    Ok(vm.ctx.new_complex(-get_value(zelf)))
}

fn complex_repr(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
    arg_check!(vm, args, required = [(obj, Some(vm.ctx.complex_type()))]);
    let v = get_value(obj);
    let repr = if v.re == 0. {
        format!("{}j", v.im)
    } else {
        format!("({}+{}j)", v.re, v.im)
    };
    Ok(vm.new_str(repr))
}
