#![allow(deprecated)] // for deprecated protocol methods
#![allow(clippy::needless_option_as_deref)]

use std::collections::HashMap;

use pyo3::exceptions::PyKeyError;
use pyo3::prelude::*;
use pyo3::py_run;
use pyo3::types::IntoPyDict;
use pyo3::types::PyList;
use pyo3::PyMappingProtocol;

mod common;

#[pyclass]
struct Mapping {
    index: HashMap<String, usize>,
}

#[pymethods]
impl Mapping {
    #[new]
    fn new(elements: Option<&PyList>) -> PyResult<Self> {
        if let Some(pylist) = elements {
            let mut elems = HashMap::with_capacity(pylist.len());
            for (i, pyelem) in pylist.into_iter().enumerate() {
                let elem = String::extract(pyelem)?;
                elems.insert(elem, i);
            }
            Ok(Self { index: elems })
        } else {
            Ok(Self {
                index: HashMap::new(),
            })
        }
    }
}

#[pyproto]
impl PyMappingProtocol for Mapping {
    fn __len__(&self) -> usize {
        self.index.len()
    }

    fn __getitem__(&self, query: String) -> PyResult<usize> {
        self.index
            .get(&query)
            .copied()
            .ok_or_else(|| PyKeyError::new_err("unknown key"))
    }

    fn __setitem__(&mut self, key: String, value: usize) {
        self.index.insert(key, value);
    }

    fn __delitem__(&mut self, key: String) -> PyResult<()> {
        if self.index.remove(&key).is_none() {
            Err(PyKeyError::new_err("unknown key"))
        } else {
            Ok(())
        }
    }

    /// not an actual reversed implementation, just to demonstrate that the method is callable.
    fn __reversed__(&self) -> PyObject {
        let gil = Python::acquire_gil();
        self.index
            .keys()
            .cloned()
            .collect::<Vec<String>>()
            .into_py(gil.python())
    }
}

/// Return a dict with `m = Mapping(['1', '2', '3'])`.
fn map_dict(py: Python) -> &pyo3::types::PyDict {
    let d = [("Mapping", py.get_type::<Mapping>())].into_py_dict(py);
    py_run!(py, *d, "m = Mapping(['1', '2', '3'])");
    d
}

#[test]
fn test_getitem() {
    let gil = Python::acquire_gil();
    let py = gil.python();
    let d = map_dict(py);

    py_assert!(py, *d, "m['1'] == 0");
    py_assert!(py, *d, "m['2'] == 1");
    py_assert!(py, *d, "m['3'] == 2");
    py_expect_exception!(py, *d, "print(m['4'])", PyKeyError);
}

#[test]
fn test_setitem() {
    let gil = Python::acquire_gil();
    let py = gil.python();
    let d = map_dict(py);

    py_run!(py, *d, "m['1'] = 4; assert m['1'] == 4");
    py_run!(py, *d, "m['0'] = 0; assert m['0'] == 0");
    py_assert!(py, *d, "len(m) == 4");
    py_expect_exception!(py, *d, "m[0] = 'hello'", PyTypeError);
    py_expect_exception!(py, *d, "m[0] = -1", PyTypeError);
}

#[test]
fn test_delitem() {
    let gil = Python::acquire_gil();
    let py = gil.python();

    let d = map_dict(py);
    py_run!(
        py,
        *d,
        "del m['1']; assert len(m) == 2 and m['2'] == 1 and m['3'] == 2"
    );
    py_expect_exception!(py, *d, "del m[-1]", PyTypeError);
    py_expect_exception!(py, *d, "del m['4']", PyKeyError);
}

#[test]
fn test_reversed() {
    let gil = Python::acquire_gil();
    let py = gil.python();

    let d = map_dict(py);
    py_assert!(py, *d, "set(reversed(m)) == {'1', '2', '3'}");
}
