use pyo3::{basic::CompareOp, exceptions::PyAttributeError, prelude::*};
use pyo3::exceptions::{PyIndexError, PyValueError};
use pyo3::types::{PySlice, PyType};
use pyo3::{ffi, py_run, AsPyPointer, PyCell};
use std::convert::TryFrom;
use std::{isize, iter};

mod common;

#[pyclass]
struct ExampleClass {
    #[pyo3(get, set)]
    value: i32,
    _custom_attr: Option<i32>,
}

#[pymethods]
impl ExampleClass {
    fn __getattr__(&self, py: Python, attr: &str) -> PyResult<PyObject> {
        if attr == "special_custom_attr" {
            Ok(self._custom_attr.into_py(py))
        } else {
            Err(PyAttributeError::new_err(attr.to_string()))
        }
    }

    fn __setattr__(&mut self, attr: &str, value: &PyAny) -> PyResult<()> {
        if attr == "special_custom_attr" {
            self._custom_attr = Some(value.extract()?);
            Ok(())
        } else {
            Err(PyAttributeError::new_err(attr.to_string()))
        }
    }

    fn __delattr__(&mut self, attr: &str) -> PyResult<()> {
        if attr == "special_custom_attr" {
            self._custom_attr = None;
            Ok(())
        } else {
            Err(PyAttributeError::new_err(attr.to_string()))
        }
    }

    fn __str__(&self) -> String {
        self.value.to_string()
    }

    fn __repr__(&self) -> String {
        format!("ExampleClass(value={})", self.value)
    }

    fn __hash__(&self) -> u64 {
        let i64_value: i64 = self.value.into();
        i64_value as u64
    }

    fn __richcmp__(&self, other: &Self, op: CompareOp) -> bool {
        op.matches_ordering(self.value.cmp(&other.value))
    }

    fn __bool__(&self) -> bool {
        self.value != 0
    }
}

fn make_example(py: Python) -> &PyCell<ExampleClass> {
    Py::new(
        py,
        ExampleClass {
            value: 5,
            _custom_attr: Some(20),
        },
    )
    .unwrap()
    .into_ref(py)
}

#[test]
fn test_getattr() {
    Python::with_gil(|py| {
        let example_py = make_example(py);
        assert_eq!(
            example_py
                .getattr("value")
                .unwrap()
                .extract::<i32>()
                .unwrap(),
            5,
        );
        assert_eq!(
            example_py
                .getattr("special_custom_attr")
                .unwrap()
                .extract::<i32>()
                .unwrap(),
            20,
        );
        assert!(example_py
            .getattr("other_attr")
            .unwrap_err()
            .is_instance::<PyAttributeError>(py));
    })
}

#[test]
fn test_setattr() {
    Python::with_gil(|py| {
        let example_py = make_example(py);
        example_py.setattr("special_custom_attr", 15).unwrap();
        assert_eq!(
            example_py
                .getattr("special_custom_attr")
                .unwrap()
                .extract::<i32>()
                .unwrap(),
            15,
        );
    })
}

#[test]
fn test_delattr() {
    Python::with_gil(|py| {
        let example_py = make_example(py);
        example_py.delattr("special_custom_attr").unwrap();
        assert!(example_py.getattr("special_custom_attr").unwrap().is_none());
    })
}

#[test]
fn test_str() {
    Python::with_gil(|py| {
        let example_py = make_example(py);
        assert_eq!(example_py.str().unwrap().to_str().unwrap(), "5");
    })
}

#[test]
fn test_repr() {
    Python::with_gil(|py| {
        let example_py = make_example(py);
        assert_eq!(
            example_py.repr().unwrap().to_str().unwrap(),
            "ExampleClass(value=5)"
        );
    })
}

#[test]
fn test_hash() {
    Python::with_gil(|py| {
        let example_py = make_example(py);
        assert_eq!(example_py.hash().unwrap(), 5);
    })
}

#[test]
fn test_richcmp() {
    Python::with_gil(|py| {
        let example_py = make_example(py);
        assert_eq!(
            example_py
                .rich_compare(example_py, CompareOp::Eq)
                .unwrap()
                .is_true()
                .unwrap(),
            true
        );
    })
}

#[test]
fn test_bool() {
    Python::with_gil(|py| {
        let example_py = make_example(py);
        assert!(example_py.is_true().unwrap());
        example_py.borrow_mut().value = 0;
        assert!(!example_py.is_true().unwrap());
    })
}

#[pyclass]
pub struct Len {
    l: usize,
}

#[pymethods]
impl Len {
    fn __len__(&self) -> usize {
        self.l
    }
}

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

    let inst = Py::new(py, Len { l: 10 }).unwrap();
    py_assert!(py, inst, "len(inst) == 10");
    unsafe {
        assert_eq!(ffi::PyObject_Size(inst.as_ptr()), 10);
        assert_eq!(ffi::PyMapping_Size(inst.as_ptr()), 10);
    }

    let inst = Py::new(
        py,
        Len {
            l: (isize::MAX as usize) + 1,
        },
    )
    .unwrap();
    py_expect_exception!(py, inst, "len(inst)", PyOverflowError);
}

#[pyclass]
struct Iterator {
    iter: Box<dyn iter::Iterator<Item = i32> + Send>,
}

#[pymethods]
impl Iterator {
    fn __iter__(slf: PyRef<Self>) -> PyRef<Self> {
        slf
    }

    fn __next__(mut slf: PyRefMut<Self>) -> Option<i32> {
        slf.iter.next()
    }
}

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

    let inst = Py::new(
        py,
        Iterator {
            iter: Box::new(5..8),
        },
    )
    .unwrap();
    py_assert!(py, inst, "iter(inst) is inst");
    py_assert!(py, inst, "list(inst) == [5, 6, 7]");
}

#[pyclass]
struct StringMethods {}

#[pymethods]
impl StringMethods {
    fn __str__(&self) -> &'static str {
        "str"
    }

    fn __repr__(&self) -> &'static str {
        "repr"
    }

    fn __format__(&self, format_spec: String) -> String {
        format!("format({})", format_spec)
    }

    fn __bytes__(&self) -> &'static [u8] {
        b"bytes"
    }
}

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

    let obj = Py::new(py, StringMethods {}).unwrap();
    py_assert!(py, obj, "str(obj) == 'str'");
    py_assert!(py, obj, "repr(obj) == 'repr'");
    py_assert!(py, obj, "'{0:x}'.format(obj) == 'format(x)'");
    py_assert!(py, obj, "bytes(obj) == b'bytes'");

    // Test that `__bytes__` takes no arguments (should be METH_NOARGS)
    py_assert!(py, obj, "obj.__bytes__() == b'bytes'");
    py_expect_exception!(py, obj, "obj.__bytes__('unexpected argument')", PyTypeError);
}

#[pyclass]
struct Comparisons {
    val: i32,
}

#[pymethods]
impl Comparisons {
    fn __hash__(&self) -> isize {
        self.val as isize
    }
    fn __bool__(&self) -> bool {
        self.val != 0
    }
}

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

    let zero = Py::new(py, Comparisons { val: 0 }).unwrap();
    let one = Py::new(py, Comparisons { val: 1 }).unwrap();
    let ten = Py::new(py, Comparisons { val: 10 }).unwrap();
    let minus_one = Py::new(py, Comparisons { val: -1 }).unwrap();
    py_assert!(py, one, "hash(one) == 1");
    py_assert!(py, ten, "hash(ten) == 10");
    py_assert!(py, minus_one, "hash(minus_one) == -2");

    py_assert!(py, one, "bool(one) is True");
    py_assert!(py, zero, "not zero");
}

#[pyclass]
#[derive(Debug)]
struct Sequence {
    fields: Vec<String>,
}

impl Default for Sequence {
    fn default() -> Sequence {
        let mut fields = vec![];
        for &s in &["A", "B", "C", "D", "E", "F", "G"] {
            fields.push(s.to_string());
        }
        Sequence { fields }
    }
}

#[pymethods]
impl Sequence {
    fn __len__(&self) -> usize {
        self.fields.len()
    }

    fn __getitem__(&self, key: isize) -> PyResult<String> {
        let idx = usize::try_from(key)?;
        if let Some(s) = self.fields.get(idx) {
            Ok(s.clone())
        } else {
            Err(PyIndexError::new_err(()))
        }
    }

    fn __setitem__(&mut self, idx: isize, value: String) -> PyResult<()> {
        let idx = usize::try_from(idx)?;
        if let Some(elem) = self.fields.get_mut(idx) {
            *elem = value;
            Ok(())
        } else {
            Err(PyIndexError::new_err(()))
        }
    }
}

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

    let c = Py::new(py, Sequence::default()).unwrap();
    py_assert!(py, c, "list(c) == ['A', 'B', 'C', 'D', 'E', 'F', 'G']");
    py_assert!(py, c, "c[-1] == 'G'");
    py_run!(
        py,
        c,
        r#"
    c[0] = 'H'
    assert c[0] == 'H'
"#
    );
    py_expect_exception!(py, c, "c['abc']", PyTypeError);
}

#[pyclass]
struct Callable {}

#[pymethods]
impl Callable {
    #[__call__]
    fn __call__(&self, arg: i32) -> i32 {
        arg * 6
    }
}

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

    let c = Py::new(py, Callable {}).unwrap();
    py_assert!(py, c, "callable(c)");
    py_assert!(py, c, "c(7) == 42");

    let nc = Py::new(py, Comparisons { val: 0 }).unwrap();
    py_assert!(py, nc, "not callable(nc)");
}

#[pyclass]
#[derive(Debug)]
struct SetItem {
    key: i32,
    val: i32,
}

#[pymethods]
impl SetItem {
    fn __setitem__(&mut self, key: i32, val: i32) {
        self.key = key;
        self.val = val;
    }
}

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

    let c = PyCell::new(py, SetItem { key: 0, val: 0 }).unwrap();
    py_run!(py, c, "c[1] = 2");
    {
        let c = c.borrow();
        assert_eq!(c.key, 1);
        assert_eq!(c.val, 2);
    }
    py_expect_exception!(py, c, "del c[1]", PyNotImplementedError);
}

#[pyclass]
struct DelItem {
    key: i32,
}

#[pymethods]
impl DelItem {
    fn __delitem__(&mut self, key: i32) {
        self.key = key;
    }
}

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

    let c = PyCell::new(py, DelItem { key: 0 }).unwrap();
    py_run!(py, c, "del c[1]");
    {
        let c = c.borrow();
        assert_eq!(c.key, 1);
    }
    py_expect_exception!(py, c, "c[1] = 2", PyNotImplementedError);
}

#[pyclass]
struct SetDelItem {
    val: Option<i32>,
}

#[pymethods]
impl SetDelItem {
    fn __setitem__(&mut self, _key: i32, val: i32) {
        self.val = Some(val);
    }

    fn __delitem__(&mut self, _key: i32) {
        self.val = None;
    }
}

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

    let c = PyCell::new(py, SetDelItem { val: None }).unwrap();
    py_run!(py, c, "c[1] = 2");
    {
        let c = c.borrow();
        assert_eq!(c.val, Some(2));
    }
    py_run!(py, c, "del c[1]");
    let c = c.borrow();
    assert_eq!(c.val, None);
}

#[pyclass]
struct Reversed {}

#[pymethods]
impl Reversed {
    fn __reversed__(&self) -> &'static str {
        "I am reversed"
    }
}

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

    let c = Py::new(py, Reversed {}).unwrap();
    py_run!(py, c, "assert reversed(c) == 'I am reversed'");
}

#[pyclass]
struct Contains {}

#[pymethods]
impl Contains {
    fn __contains__(&self, item: i32) -> bool {
        item >= 0
    }
}

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

    let c = Py::new(py, Contains {}).unwrap();
    py_run!(py, c, "assert 1 in c");
    py_run!(py, c, "assert -1 not in c");
    py_expect_exception!(py, c, "assert 'wrong type' not in c", PyTypeError);
}

#[pyclass]
struct ContextManager {
    exit_called: bool,
}

#[pymethods]
impl ContextManager {
    fn __enter__(&mut self) -> i32 {
        42
    }

    fn __exit__(
        &mut self,
        ty: Option<&PyType>,
        _value: Option<&PyAny>,
        _traceback: Option<&PyAny>,
    ) -> bool {
        let gil = Python::acquire_gil();
        self.exit_called = true;
        ty == Some(gil.python().get_type::<PyValueError>())
    }
}

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

    let c = PyCell::new(py, ContextManager { exit_called: false }).unwrap();
    py_run!(py, c, "with c as x: assert x == 42");
    {
        let mut c = c.borrow_mut();
        assert!(c.exit_called);
        c.exit_called = false;
    }
    py_run!(py, c, "with c as x: raise ValueError");
    {
        let mut c = c.borrow_mut();
        assert!(c.exit_called);
        c.exit_called = false;
    }
    py_expect_exception!(
        py,
        c,
        "with c as x: raise NotImplementedError",
        PyNotImplementedError
    );
    let c = c.borrow();
    assert!(c.exit_called);
}

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

    let v = PySlice::new(py, 1, 10, 2);
    let indices = v.indices(100).unwrap();
    assert_eq!(1, indices.start);
    assert_eq!(10, indices.stop);
    assert_eq!(2, indices.step);
    assert_eq!(5, indices.slicelength);
}

#[pyclass]
struct Test {}

#[pymethods]
impl Test {
    fn __getitem__(&self, idx: &PyAny) -> PyResult<&'static str> {
        if let Ok(slice) = idx.cast_as::<PySlice>() {
            let indices = slice.indices(1000)?;
            if indices.start == 100 && indices.stop == 200 && indices.step == 1 {
                return Ok("slice");
            }
        } else if let Ok(idx) = idx.extract::<isize>() {
            if idx == 1 {
                return Ok("int");
            }
        }
        Err(PyValueError::new_err("error"))
    }
}

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

    let ob = Py::new(py, Test {}).unwrap();

    py_assert!(py, ob, "ob[1] == 'int'");
    py_assert!(py, ob, "ob[100:200:1] == 'slice'");
}

#[pyclass]
struct ClassWithGetAttr {
    #[pyo3(get, set)]
    data: u32,
}

#[pymethods]
impl ClassWithGetAttr {
    fn __getattr__(&self, _name: &str) -> u32 {
        self.data * 2
    }
}

#[test]
fn getattr_doesnt_override_member() {
    let gil = Python::acquire_gil();
    let py = gil.python();
    let inst = PyCell::new(py, ClassWithGetAttr { data: 4 }).unwrap();
    py_assert!(py, inst, "inst.data == 4");
    py_assert!(py, inst, "inst.a == 8");
}

/// Wraps a Python future and yield it once.
#[pyclass]
struct OnceFuture {
    future: PyObject,
    polled: bool,
}

#[pymethods]
impl OnceFuture {
    #[new]
    fn new(future: PyObject) -> Self {
        OnceFuture {
            future,
            polled: false,
        }
    }

    fn __await__(slf: PyRef<Self>) -> PyRef<Self> {
        slf
    }

    fn __iter__(slf: PyRef<Self>) -> PyRef<Self> {
        slf
    }
    fn __next__(mut slf: PyRefMut<Self>) -> Option<PyObject> {
        if !slf.polled {
            slf.polled = true;
            Some(slf.future.clone())
        } else {
            None
        }
    }
}

#[test]
fn test_await() {
    let gil = Python::acquire_gil();
    let py = gil.python();
    let once = py.get_type::<OnceFuture>();
    let source = pyo3::indoc::indoc!(
        r#"
import asyncio
import sys

async def main():
    res = await Once(await asyncio.sleep(0.1))
    return res
# For an odd error similar to https://bugs.python.org/issue38563
if sys.platform == "win32" and sys.version_info >= (3, 8, 0):
    asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
# get_event_loop can raise an error: https://github.com/PyO3/pyo3/pull/961#issuecomment-645238579
loop = asyncio.new_event_loop()
asyncio.set_event_loop(loop)
assert loop.run_until_complete(main()) is None
loop.close()
"#
    );
    let globals = PyModule::import(py, "__main__").unwrap().dict();
    globals.set_item("Once", once).unwrap();
    py.run(source, Some(globals), None)
        .map_err(|e| e.print(py))
        .unwrap();
}

/// Increment the count when `__get__` is called.
#[pyclass]
struct DescrCounter {
    #[pyo3(get)]
    count: usize,
}

#[pymethods]
impl DescrCounter {
    #[new]
    fn new() -> Self {
        DescrCounter { count: 0 }
    }

    fn __get__<'a>(
        mut slf: PyRefMut<'a, Self>,
        _instance: &PyAny,
        _owner: Option<&PyType>,
    ) -> PyRefMut<'a, Self> {
        slf.count += 1;
        slf
    }
    fn __set__(_slf: PyRef<Self>, _instance: &PyAny, mut new_value: PyRefMut<Self>) {
        new_value.count = _slf.count;
    }
}

#[test]
fn descr_getset() {
    let gil = Python::acquire_gil();
    let py = gil.python();
    let counter = py.get_type::<DescrCounter>();
    let source = pyo3::indoc::indoc!(
        r#"
class Class:
    counter = Counter()
c = Class()
c.counter # count += 1
assert c.counter.count == 2
c.counter = Counter()
assert c.counter.count == 3
"#
    );
    let globals = PyModule::import(py, "__main__").unwrap().dict();
    globals.set_item("Counter", counter).unwrap();
    py.run(source, Some(globals), None)
        .map_err(|e| e.print(py))
        .unwrap();
}


// TODO: test __delete__
// TODO: better argument casting errors