use crate::err::PyResult;
use crate::ffi_ptr_ext::FfiPtrExt;
use crate::py_result_ext::PyResultExt;
use crate::{ffi, Bound, PyAny};
#[cfg(RustPython)]
use crate::{
    sync::PyOnceLock,
    types::{PyType, PyTypeMethods},
    Py,
};

/// Represents a Python `memoryview`.
///
/// Values of this type are accessed via PyO3's smart pointers, e.g. as
/// [`Py<PyMemoryView>`][crate::Py] or [`Bound<'py, PyMemoryView>`][Bound].
#[repr(transparent)]
pub struct PyMemoryView(PyAny);

#[cfg(not(RustPython))]
pyobject_native_type_core!(PyMemoryView, pyobject_native_static_type_object!(ffi::PyMemoryView_Type), "builtins", "memoryview", #checkfunction=ffi::PyMemoryView_Check);

#[cfg(RustPython)]
pyobject_native_type_core!(
    PyMemoryView,
    |py| {
        static TYPE: PyOnceLock<Py<PyType>> = PyOnceLock::new();
        TYPE.import(py, "builtins", "memoryview").unwrap().as_type_ptr()
    },
    "builtins",
    "memoryview",
    #checkfunction=ffi::PyMemoryView_Check
);

impl PyMemoryView {
    /// Creates a new Python `memoryview` object from another Python object that
    /// implements the buffer protocol.
    pub fn from<'py>(src: &Bound<'py, PyAny>) -> PyResult<Bound<'py, Self>> {
        unsafe {
            ffi::PyMemoryView_FromObject(src.as_ptr())
                .assume_owned_or_err(src.py())
                .cast_into_unchecked()
        }
    }
}

impl<'py> TryFrom<&Bound<'py, PyAny>> for Bound<'py, PyMemoryView> {
    type Error = crate::PyErr;

    /// Creates a new Python `memoryview` object from another Python object that
    /// implements the buffer protocol.
    fn try_from(value: &Bound<'py, PyAny>) -> Result<Self, Self::Error> {
        PyMemoryView::from(value)
    }
}
