import os
import sys
import copy
import pytest

from numpy import (
    array, alltrue, ndarray, zeros, dtype, intp, clongdouble
    )
from numpy.testing import assert_, assert_equal
from numpy.core.multiarray import typeinfo
from . import util

wrap = None


def setup_module():
    """
    Build the required testing extension module

    """
    global wrap

    # Check compiler availability first
    if not util.has_c_compiler():
        pytest.skip("No C compiler available")

    if wrap is None:
        config_code = """
        config.add_extension('test_array_from_pyobj_ext',
                             sources=['wrapmodule.c', 'fortranobject.c'],
                             define_macros=[])
        """
        d = os.path.dirname(__file__)
        src = [os.path.join(d, 'src', 'array_from_pyobj', 'wrapmodule.c'),
               os.path.join(d, '..', 'src', 'fortranobject.c'),
               os.path.join(d, '..', 'src', 'fortranobject.h')]
        wrap = util.build_module_distutils(src, config_code,
                                           'test_array_from_pyobj_ext')


def flags_info(arr):
    flags = wrap.array_attrs(arr)[6]
    return flags2names(flags)


def flags2names(flags):
    info = []
    for flagname in ['CONTIGUOUS', 'FORTRAN', 'OWNDATA', 'ENSURECOPY',
                     'ENSUREARRAY', 'ALIGNED', 'NOTSWAPPED', 'WRITEABLE',
                     'WRITEBACKIFCOPY', 'UPDATEIFCOPY', 'BEHAVED', 'BEHAVED_RO',
                     'CARRAY', 'FARRAY'
                     ]:
        if abs(flags) & getattr(wrap, flagname, 0):
            info.append(flagname)
    return info


class Intent:

    def __init__(self, intent_list=[]):
        self.intent_list = intent_list[:]
        flags = 0
        for i in intent_list:
            if i == 'optional':
                flags |= wrap.F2PY_OPTIONAL
            else:
                flags |= getattr(wrap, 'F2PY_INTENT_' + i.upper())
        self.flags = flags

    def __getattr__(self, name):
        name = name.lower()
        if name == 'in_':
            name = 'in'
        return self.__class__(self.intent_list + [name])

    def __str__(self):
        return 'intent(%s)' % (','.join(self.intent_list))

    def __repr__(self):
        return 'Intent(%r)' % (self.intent_list)

    def is_intent(self, *names):
        for name in names:
            if name not in self.intent_list:
                return False
        return True

    def is_intent_exact(self, *names):
        return len(self.intent_list) == len(names) and self.is_intent(*names)

intent = Intent()

_type_names = ['BOOL', 'BYTE', 'UBYTE', 'SHORT', 'USHORT', 'INT', 'UINT',
               'LONG', 'ULONG', 'LONGLONG', 'ULONGLONG',
               'FLOAT', 'DOUBLE', 'CFLOAT']

_cast_dict = {'BOOL': ['BOOL']}
_cast_dict['BYTE'] = _cast_dict['BOOL'] + ['BYTE']
_cast_dict['UBYTE'] = _cast_dict['BOOL'] + ['UBYTE']
_cast_dict['BYTE'] = ['BYTE']
_cast_dict['UBYTE'] = ['UBYTE']
_cast_dict['SHORT'] = _cast_dict['BYTE'] + ['UBYTE', 'SHORT']
_cast_dict['USHORT'] = _cast_dict['UBYTE'] + ['BYTE', 'USHORT']
_cast_dict['INT'] = _cast_dict['SHORT'] + ['USHORT', 'INT']
_cast_dict['UINT'] = _cast_dict['USHORT'] + ['SHORT', 'UINT']

_cast_dict['LONG'] = _cast_dict['INT'] + ['LONG']
_cast_dict['ULONG'] = _cast_dict['UINT'] + ['ULONG']

_cast_dict['LONGLONG'] = _cast_dict['LONG'] + ['LONGLONG']
_cast_dict['ULONGLONG'] = _cast_dict['ULONG'] + ['ULONGLONG']

_cast_dict['FLOAT'] = _cast_dict['SHORT'] + ['USHORT', 'FLOAT']
_cast_dict['DOUBLE'] = _cast_dict['INT'] + ['UINT', 'FLOAT', 'DOUBLE']

_cast_dict['CFLOAT'] = _cast_dict['FLOAT'] + ['CFLOAT']

# 32 bit system malloc typically does not provide the alignment required by
# 16 byte long double types this means the inout intent cannot be satisfied
# and several tests fail as the alignment flag can be randomly true or fals
# when numpy gains an aligned allocator the tests could be enabled again
if ((intp().dtype.itemsize != 4 or clongdouble().dtype.alignment <= 8) and
        sys.platform != 'win32'):
    _type_names.extend(['LONGDOUBLE', 'CDOUBLE', 'CLONGDOUBLE'])
    _cast_dict['LONGDOUBLE'] = _cast_dict['LONG'] + \
        ['ULONG', 'FLOAT', 'DOUBLE', 'LONGDOUBLE']
    _cast_dict['CLONGDOUBLE'] = _cast_dict['LONGDOUBLE'] + \
        ['CFLOAT', 'CDOUBLE', 'CLONGDOUBLE']
    _cast_dict['CDOUBLE'] = _cast_dict['DOUBLE'] + ['CFLOAT', 'CDOUBLE']


class Type:
    _type_cache = {}

    def __new__(cls, name):
        if isinstance(name, dtype):
            dtype0 = name
            name = None
            for n, i in typeinfo.items():
                if not isinstance(i, type) and dtype0.type is i.type:
                    name = n
                    break
        obj = cls._type_cache.get(name.upper(), None)
        if obj is not None:
            return obj
        obj = object.__new__(cls)
        obj._init(name)
        cls._type_cache[name.upper()] = obj
        return obj

    def _init(self, name):
        self.NAME = name.upper()
        info = typeinfo[self.NAME]
        self.type_num = getattr(wrap, 'NPY_' + self.NAME)
        assert_equal(self.type_num, info.num)
        self.dtype = info.type
        self.elsize = info.bits / 8
        self.dtypechar = info.char

    def cast_types(self):
        return [self.__class__(_m) for _m in _cast_dict[self.NAME]]

    def all_types(self):
        return [self.__class__(_m) for _m in _type_names]

    def smaller_types(self):
        bits = typeinfo[self.NAME].alignment
        types = []
        for name in _type_names:
            if typeinfo[name].alignment < bits:
                types.append(Type(name))
        return types

    def equal_types(self):
        bits = typeinfo[self.NAME].alignment
        types = []
        for name in _type_names:
            if name == self.NAME:
                continue
            if typeinfo[name].alignment == bits:
                types.append(Type(name))
        return types

    def larger_types(self):
        bits = typeinfo[self.NAME].alignment
        types = []
        for name in _type_names:
            if typeinfo[name].alignment > bits:
                types.append(Type(name))
        return types


class Array:

    def __init__(self, typ, dims, intent, obj):
        self.type = typ
        self.dims = dims
        self.intent = intent
        self.obj_copy = copy.deepcopy(obj)
        self.obj = obj

        # arr.dtypechar may be different from typ.dtypechar
        self.arr = wrap.call(typ.type_num, dims, intent.flags, obj)

        assert_(isinstance(self.arr, ndarray), repr(type(self.arr)))

        self.arr_attr = wrap.array_attrs(self.arr)

        if len(dims) > 1:
            if self.intent.is_intent('c'):
                assert_(intent.flags & wrap.F2PY_INTENT_C)
                assert_(not self.arr.flags['FORTRAN'],
                        repr((self.arr.flags, getattr(obj, 'flags', None))))
                assert_(self.arr.flags['CONTIGUOUS'])
                assert_(not self.arr_attr[6] & wrap.FORTRAN)
            else:
                assert_(not intent.flags & wrap.F2PY_INTENT_C)
                assert_(self.arr.flags['FORTRAN'])
                assert_(not self.arr.flags['CONTIGUOUS'])
                assert_(self.arr_attr[6] & wrap.FORTRAN)

        if obj is None:
            self.pyarr = None
            self.pyarr_attr = None
            return

        if intent.is_intent('cache'):
            assert_(isinstance(obj, ndarray), repr(type(obj)))
            self.pyarr = array(obj).reshape(*dims).copy()
        else:
            self.pyarr = array(array(obj, dtype=typ.dtypechar).reshape(*dims),
                               order=self.intent.is_intent('c') and 'C' or 'F')
            assert_(self.pyarr.dtype == typ,
                    repr((self.pyarr.dtype, typ)))
        assert_(self.pyarr.flags['OWNDATA'], (obj, intent))
        self.pyarr_attr = wrap.array_attrs(self.pyarr)

        if len(dims) > 1:
            if self.intent.is_intent('c'):
                assert_(not self.pyarr.flags['FORTRAN'])
                assert_(self.pyarr.flags['CONTIGUOUS'])
                assert_(not self.pyarr_attr[6] & wrap.FORTRAN)
            else:
                assert_(self.pyarr.flags['FORTRAN'])
                assert_(not self.pyarr.flags['CONTIGUOUS'])
                assert_(self.pyarr_attr[6] & wrap.FORTRAN)

        assert_(self.arr_attr[1] == self.pyarr_attr[1])  # nd
        assert_(self.arr_attr[2] == self.pyarr_attr[2])  # dimensions
        if self.arr_attr[1] <= 1:
            assert_(self.arr_attr[3] == self.pyarr_attr[3],
                    repr((self.arr_attr[3], self.pyarr_attr[3],
                          self.arr.tobytes(), self.pyarr.tobytes())))  # strides
        assert_(self.arr_attr[5][-2:] == self.pyarr_attr[5][-2:],
                repr((self.arr_attr[5], self.pyarr_attr[5])))  # descr
        assert_(self.arr_attr[6] == self.pyarr_attr[6],
                repr((self.arr_attr[6], self.pyarr_attr[6],
                      flags2names(0 * self.arr_attr[6] - self.pyarr_attr[6]),
                      flags2names(self.arr_attr[6]), intent)))  # flags

        if intent.is_intent('cache'):
            assert_(self.arr_attr[5][3] >= self.type.elsize,
                    repr((self.arr_attr[5][3], self.type.elsize)))
        else:
            assert_(self.arr_attr[5][3] == self.type.elsize,
                    repr((self.arr_attr[5][3], self.type.elsize)))
        assert_(self.arr_equal(self.pyarr, self.arr))

        if isinstance(self.obj, ndarray):
            if typ.elsize == Type(obj.dtype).elsize:
                if not intent.is_intent('copy') and self.arr_attr[1] <= 1:
                    assert_(self.has_shared_memory())

    def arr_equal(self, arr1, arr2):
        if arr1.shape != arr2.shape:
            return False
        s = arr1 == arr2
        return alltrue(s.flatten())

    def __str__(self):
        return str(self.arr)

    def has_shared_memory(self):
        """Check that created array shares data with input array.
        """
        if self.obj is self.arr:
            return True
        if not isinstance(self.obj, ndarray):
            return False
        obj_attr = wrap.array_attrs(self.obj)
        return obj_attr[0] == self.arr_attr[0]


class TestIntent:

    def test_in_out(self):
        assert_equal(str(intent.in_.out), 'intent(in,out)')
        assert_(intent.in_.c.is_intent('c'))
        assert_(not intent.in_.c.is_intent_exact('c'))
        assert_(intent.in_.c.is_intent_exact('c', 'in'))
        assert_(intent.in_.c.is_intent_exact('in', 'c'))
        assert_(not intent.in_.is_intent('c'))


class TestSharedMemory:
    num2seq = [1, 2]
    num23seq = [[1, 2, 3], [4, 5, 6]]

    @pytest.fixture(autouse=True, scope='class', params=_type_names)
    def setup_type(self, request):
        request.cls.type = Type(request.param)
        request.cls.array = lambda self, dims, intent, obj: \
            Array(Type(request.param), dims, intent, obj)

    def test_in_from_2seq(self):
        a = self.array([2], intent.in_, self.num2seq)
        assert_(not a.has_shared_memory())

    def test_in_from_2casttype(self):
        for t in self.type.cast_types():
            obj = array(self.num2seq, dtype=t.dtype)
            a = self.array([len(self.num2seq)], intent.in_, obj)
            if t.elsize == self.type.elsize:
                assert_(
                    a.has_shared_memory(), repr((self.type.dtype, t.dtype)))
            else:
                assert_(not a.has_shared_memory(), repr(t.dtype))

    def test_inout_2seq(self):
        obj = array(self.num2seq, dtype=self.type.dtype)
        a = self.array([len(self.num2seq)], intent.inout, obj)
        assert_(a.has_shared_memory())

        try:
            a = self.array([2], intent.in_.inout, self.num2seq)
        except TypeError as msg:
            if not str(msg).startswith('failed to initialize intent'
                                       '(inout|inplace|cache) array'):
                raise
        else:
            raise SystemError('intent(inout) should have failed on sequence')

    def test_f_inout_23seq(self):
        obj = array(self.num23seq, dtype=self.type.dtype, order='F')
        shape = (len(self.num23seq), len(self.num23seq[0]))