// Copyright (c) 2015 Daniel Grunwald
//
// Permission is hereby granted, free of charge, to any person obtaining a copy of this
// software and associated documentation files (the "Software"), to deal in the Software
// without restriction, including without limitation the rights to use, copy, modify, merge,
// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
// to whom the Software is furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all copies or
// substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
// DEALINGS IN THE SOFTWARE.

use libc::c_char;
use std::ffi::{CStr, CString};

use crate::conversion::ToPyObject;
use crate::err::{self, PyErr, PyResult};
use crate::ffi;
use crate::objectprotocol::ObjectProtocol;
use crate::objects::{exc, PyDict, PyObject, PyTuple};
use crate::py_class::PythonObjectFromPyClassMacro;
use crate::python::{PyDrop, Python, PythonObject};

/// Represents a Python module object.
pub struct PyModule(PyObject);

pyobject_newtype!(PyModule, PyModule_Check, PyModule_Type);

impl PyModule {
    /// Create a new module object with the `__name__` attribute set to name.
    pub fn new(py: Python, name: &str) -> PyResult<PyModule> {
        let name = CString::new(name).unwrap();
        unsafe { err::result_cast_from_owned_ptr(py, ffi::PyModule_New(name.as_ptr())) }
    }

    /// Import the Python module with the specified name.
    pub fn import(py: Python, name: &str) -> PyResult<PyModule> {
        let name = CString::new(name).unwrap();
        unsafe { err::result_cast_from_owned_ptr(py, ffi::PyImport_ImportModule(name.as_ptr())) }
    }

    /// Return the dictionary object that implements module's namespace;
    /// this object is the same as the `__dict__` attribute of the module object.
    pub fn dict(&self, py: Python) -> PyDict {
        unsafe {
            let r = PyObject::from_borrowed_ptr(py, ffi::PyModule_GetDict(self.0.as_ptr()));
            r.unchecked_cast_into::<PyDict>()
        }
    }

    unsafe fn str_from_ptr<'a>(&'a self, py: Python, ptr: *const c_char) -> PyResult<&'a str> {
        if ptr.is_null() {
            Err(PyErr::fetch(py))
        } else {
            let slice = CStr::from_ptr(ptr).to_bytes();
            match std::str::from_utf8(slice) {
                Ok(s) => Ok(s),
                Err(e) => Err(PyErr::from_instance(
                    py,
                    exc::UnicodeDecodeError::new_utf8(py, slice, e)?,
                )),
            }
        }
    }

    /// Gets the module name.
    ///
    /// May fail if the module does not have a `__name__` attribute.
    pub fn name<'a>(&'a self, py: Python) -> PyResult<&'a str> {
        unsafe { self.str_from_ptr(py, ffi::PyModule_GetName(self.0.as_ptr())) }
    }

    /// Gets the module filename.
    ///
    /// May fail if the module does not have a `__file__` attribute.
    #[allow(deprecated)]
    pub fn filename(&self, py: Python) -> PyResult<&str> {
        unsafe { self.str_from_ptr(py, ffi::PyModule_GetFilename(self.0.as_ptr())) }
    }

    /// Gets the module filename object.
    ///
    /// May fail if the module does not have a `__file__` attribute.
    #[cfg(feature = "python3-sys")]
    pub fn filename_object(&self, py: Python) -> PyResult<PyObject> {
        let ptr = unsafe { ffi::PyModule_GetFilenameObject(self.0.as_ptr()) };
        if ptr.is_null() {
            Err(PyErr::fetch(py))
        } else {
            Ok(unsafe { PyObject::from_borrowed_ptr(py, ptr) })
        }
    }

    /// Gets a member from the module.
    /// This is equivalent to the Python expression: `getattr(module, name)`
    pub fn get(&self, py: Python, name: &str) -> PyResult<PyObject> {
        self.as_object().getattr(py, name)
    }

    /// Calls a function in the module.
    /// This is equivalent to the Python expression: `getattr(module, name)(*args, **kwargs)`
    ///
    /// `args` should be a value that, when converted to Python, results in a tuple.
    /// For this purpose, you can use:
    ///  * `cpython::NoArgs` when calling a method without any arguments
    ///  * otherwise, a Rust tuple with 1 or more elements
    ///
    /// # Example
    /// ```
    /// use cpython::NoArgs;
    /// # use cpython::Python;
    /// # let gil = Python::acquire_gil();
    /// # let py = gil.python();
    /// let sys = py.import("sys").unwrap();
    /// // Call function without arguments:
    /// let encoding = sys.call(py, "getdefaultencoding", NoArgs, None).unwrap();
    /// // Call function with a single argument:
    /// sys.call(py, "setrecursionlimit", (1000,), None).unwrap();
    /// ```
    pub fn call<A>(
        &self,
        py: Python,
        name: &str,
        args: A,
        kwargs: Option<&PyDict>,
    ) -> PyResult<PyObject>
    where
        A: ToPyObject<ObjectType = PyTuple>,
    {
        self.as_object().getattr(py, name)?.call(py, args, kwargs)
    }

    /// Adds a member to the module.
    ///
    /// This is a convenience function which can be used from the module's initialization function.
    pub fn add<V>(&self, py: Python, name: &str, value: V) -> PyResult<()>
    where
        V: ToPyObject,
    {
        self.as_object().setattr(py, name, value)
    }

    /// Adds a new extension type to the module.
    ///
    /// This is a convenience function that initializes the `py_class!()`,
    /// sets `new_type.__module__` to this module's name,
    /// and adds the type to this module.
    pub fn add_class<T>(&self, py: Python<'_>) -> PyResult<()>
    where
        T: PythonObjectFromPyClassMacro,
    {
        T::add_to_module(py, self)
    }
}