import numpy as np

from numba import njit
import unittest
from numba.core.compiler import compile_isolated, Flags
from numba.core import types, errors
from numba.tests.support import TestCase, MemoryLeakMixin, tag
from numba.np import numpy_support

enable_pyobj_flags = Flags()
enable_pyobj_flags.enable_pyobject = True

force_pyobj_flags = Flags()
force_pyobj_flags.force_pyobject = True

no_pyobj_flags = Flags()


def int_tuple_iter_usecase():
    res = 0
    for i in (1, 2, 99, 3):
        res += i
    return res

def float_tuple_iter_usecase():
    res = 0.0
    for i in (1.5, 2.0, 99.3, 3.4):
        res += i
    return res

def tuple_tuple_iter_usecase():
    # Recursively homogeneous tuple type
    res = 0.0
    for i in ((1.5, 2.0), (99.3, 3.4), (1.8, 2.5)):
        for j in i:
            res += j
        res = res * 2
    return res

def enumerate_nested_tuple_usecase():
    res = 0.0
    for i, j in enumerate(((1.5, 2.0), (99.3, 3.4), (1.8, 2.5))):
        for l in j:
            res += i * l
        res = res * 2
    return res

def nested_enumerate_usecase():
    res = 0.0
    for i, (j, k) in enumerate(enumerate(((1.5, 2.0), (99.3, 3.4), (1.8, 2.5)))):
        for l in k:
            res += i * j * l
        res = res * 2
    return res


def enumerate_array_usecase():
    res = 0
    arrays = (np.ones(4), np.ones(5))
    for i, v in enumerate(arrays):
        res += v.sum()
    return res


def scalar_iter_usecase(iterable):
    res = 0.0
    for x in iterable:
        res += x
    return res

def record_iter_usecase(iterable):
    res = 0.0
    for x in iterable:
        res += x.a * x.b
    return res

def record_iter_mutate_usecase(iterable):
    for x in iterable:
        x.a = x.a + x.b


record_dtype = np.dtype([('a', np.float64),
                         ('b', np.int32),
                         ])


class IterationTest(MemoryLeakMixin, TestCase):

    def run_nullary_func(self, pyfunc, flags):
        cr = compile_isolated(pyfunc, (), flags=flags)
        cfunc = cr.entry_point
        expected = pyfunc()
        self.assertPreciseEqual(cfunc(), expected)

    def test_int_tuple_iter(self, flags=force_pyobj_flags):
        self.run_nullary_func(int_tuple_iter_usecase, flags)

    def test_int_tuple_iter_npm(self):
        self.test_int_tuple_iter(flags=no_pyobj_flags)

    # Type inference on tuples used to be hardcoded for ints, check
    # that it works for other types.

    def test_float_tuple_iter(self, flags=force_pyobj_flags):
        self.run_nullary_func(float_tuple_iter_usecase, flags)

    def test_float_tuple_iter_npm(self):
        self.test_float_tuple_iter(flags=no_pyobj_flags)

    def test_tuple_tuple_iter(self, flags=force_pyobj_flags):
        self.run_nullary_func(tuple_tuple_iter_usecase, flags)

    def test_tuple_tuple_iter_npm(self):
        self.test_tuple_tuple_iter(flags=no_pyobj_flags)

    def test_enumerate_nested_tuple(self, flags=force_pyobj_flags):
        self.run_nullary_func(enumerate_nested_tuple_usecase, flags)

    def test_enumerate_nested_tuple_npm(self):
        self.test_enumerate_nested_tuple(flags=no_pyobj_flags)

    def test_nested_enumerate(self, flags=force_pyobj_flags):
        self.run_nullary_func(nested_enumerate_usecase, flags)

    def test_nested_enumerate_npm(self):
        self.test_nested_enumerate(flags=no_pyobj_flags)

    def test_enumerate_refct(self):
        # Test issue 3473
        pyfunc = enumerate_array_usecase
        cr = compile_isolated(pyfunc, ())
        cfunc = cr.entry_point
        expected = pyfunc()
        self.assertPreciseEqual(cfunc(), expected)

    def run_array_1d(self, item_type, arg, flags):
        # Iteration over a 1d numpy array
        pyfunc = scalar_iter_usecase
        cr = compile_isolated(pyfunc, (types.Array(item_type, 1, 'A'),),
                              item_type, flags=flags)
        cfunc = cr.entry_point
        self.assertPreciseEqual(cfunc(arg), pyfunc(arg))

    def test_array_1d_float(self, flags=force_pyobj_flags):
        self.run_array_1d(types.float64, np.arange(5.0), flags)

    def test_array_1d_float_npm(self):
        self.test_array_1d_float(no_pyobj_flags)

    def test_array_1d_complex(self, flags=force_pyobj_flags):
        self.run_array_1d(types.complex128, np.arange(5.0) * 1.0j, flags)

    def test_array_1d_complex_npm(self):
        self.test_array_1d_complex(no_pyobj_flags)

    def test_array_1d_record(self, flags=force_pyobj_flags):
        pyfunc = record_iter_usecase
        item_type = numpy_support.from_dtype(record_dtype)
        cr = compile_isolated(pyfunc, (types.Array(item_type, 1, 'A'),),
                              flags=flags)
        cfunc = cr.entry_point
        arr = np.recarray(3, dtype=record_dtype)
        for i in range(3):
            arr[i].a = float(i * 2)
            arr[i].b = i + 2
        got = pyfunc(arr)
        self.assertPreciseEqual(cfunc(arr), got)

    def test_array_1d_record_npm(self):
        self.test_array_1d_record(no_pyobj_flags)

    def test_array_1d_record_mutate_npm(self, flags=no_pyobj_flags):
        pyfunc = record_iter_mutate_usecase
        item_type = numpy_support.from_dtype(record_dtype)
        cr = compile_isolated(pyfunc, (types.Array(item_type, 1, 'A'),),
                              flags=flags)
        cfunc = cr.entry_point
        arr = np.recarray(3, dtype=record_dtype)
        for i in range(3):
            arr[i].a = float(i * 2)
            arr[i].b = i + 2
        expected = arr.copy()
        pyfunc(expected)
        got = arr.copy()
        cfunc(got)
        self.assertPreciseEqual(expected, got)

    def test_array_1d_record_mutate(self):
        self.test_array_1d_record_mutate_npm(flags=force_pyobj_flags)

    def test_array_0d_raises(self):

        def foo(x):
            for i in x:
                pass

        # 0d is typing error
        with self.assertRaises(errors.TypingError) as raises:
            aryty = types.Array(types.int32, 0, 'C')
            compile_isolated(foo, (aryty,))

        self.assertIn("0-d array", str(raises.exception))

    def test_tuple_iter_issue1504(self):
        # The issue is due to `row` being typed as heterogeneous tuple.
        def bar(x, y):
            total = 0
            for row in zip(x, y):
                total += row[0] + row[1]

            return total

        x = y = np.arange(3, dtype=np.int32)
        aryty = types.Array(types.int32, 1, 'C')
        cres = compile_isolated(bar, (aryty, aryty))

        expect = bar(x, y)
        got = cres.entry_point(x, y)
        self.assertEqual(expect, got)

    def test_tuple_of_arrays_iter(self):
        # We used to leak a reference to each element of the tuple
        def bar(arrs):
            total = 0
            for arr in arrs:
                total += arr[0]

            return total

        x = y = np.arange(3, dtype=np.int32)
        aryty = types.Array(types.int32, 1, 'C')
        cres = compile_isolated(bar, (types.containers.UniTuple(aryty, 2),))

        expect = bar((x, y))
        got = cres.entry_point((x, y))
        self.assertEqual(expect, got)



class TestIterationRefct(MemoryLeakMixin, TestCase):
    def test_zip_with_arrays(self):
        @njit
        def foo(sequence):
            c = 0
            for a, b in zip(range(len(sequence)), sequence):
                c += (a + 1) * b.sum()
            return

        sequence = [np.arange(1 + i) for i in range(10)]
        self.assertEqual(foo(sequence), foo.py_func(sequence))


if __name__ == '__main__':
    unittest.main()
