#![feature(specialization)]

#[macro_use]
extern crate pyo3;

use pyo3::prelude::*;

#[pyclass(module = "unit_converter")]
struct Temperature {
    celsius: f32,
}

#[pymethods]
impl Temperature {
    #[new]
    fn new(obj: &PyRawObject, temperature: f32) {
        obj.init(Temperature {
            celsius: temperature,
        });
    }

    fn to_fahrenheit(&self) -> f32 {
        self.celsius * 1.8 + 32.0
    }

    fn windchill(&self, wind_speed_kph: f32) -> f32 {
        13.12 + (0.6215 * self.celsius) - (11.37 * wind_speed_kph.powf(0.16))
            + (0.3965 * self.celsius * wind_speed_kph.powf(0.16))
    }
}

// TODO: Add a test that -20 C and 32 kph feels like -32.9

#[pyfunction]
fn convert_to_fahrenheit(celsius: f32) -> f32 {
    celsius * 1.8 + 32.0
}

#[pyfunction]
fn batch_convert_to_fahrenheit(celsius: Vec<f32>) -> Vec<f32> {
    celsius
        .iter()
        .map(|temperature| convert_to_fahrenheit(temperature.clone()))
        .collect()
}

#[pymodule]
fn unit_converter(_py: Python, m: &PyModule) -> PyResult<()> {
    m.add_wrapped(wrap_pyfunction!(convert_to_fahrenheit))?;
    m.add_wrapped(wrap_pyfunction!(batch_convert_to_fahrenheit))?;
    m.add_class::<Temperature>()?;
    Ok(())
}

#[cfg(test)]
mod tests {

    use super::convert_to_fahrenheit;

    #[test]
    fn conversion_celsius_to_fahrenheit() {
        assert_eq!(convert_to_fahrenheit(25.0), 77.0);
    }
}