# Licensed under a 3-clause BSD style license - see LICENSE.rst
from __future__ import with_statement


import os
import signal
import gzip
from sys import version_info

import pytest
import numpy as np

try:
    from PIL import Image
    HAS_PIL = True
except ImportError:
    HAS_PIL = False

from ....tests.helper import catch_warnings
from .. import util
from ..util import ignore_sigint
from .._numpy_hacks import realign_dtype

from . import FitsTestCase


class TestUtils(FitsTestCase):
    @pytest.mark.skipif("sys.platform.startswith('win')")
    def test_ignore_sigint(self):
        @ignore_sigint
        def test():
            with catch_warnings(UserWarning) as w:
                pid = os.getpid()
                os.kill(pid, signal.SIGINT)
                # One more time, for good measure
                os.kill(pid, signal.SIGINT)
            assert len(w) == 2
            assert (str(w[0].message) ==
                    'KeyboardInterrupt ignored until test is complete!')

        pytest.raises(KeyboardInterrupt, test)

    def test_realign_dtype(self):
        """
        Tests a few corner-cases for the realign_dtype hack.

        These are unlikely to come in practice given how this is currently
        used in astropy.io.fits, but nonetheless tests for bugs that were
        present in earlier versions of the function.
        """

        dt = np.dtype([('a', np.int32), ('b', np.int16)])
        dt2 = realign_dtype(dt, [0, 0])
        assert dt2.itemsize == 4

        dt2 = realign_dtype(dt, [0, 1])
        assert dt2.itemsize == 4

        dt2 = realign_dtype(dt, [1, 0])
        assert dt2.itemsize == 5

        dt = np.dtype([('a', np.float64), ('b', np.int8), ('c', np.int8)])
        dt2 = realign_dtype(dt, [0, 0, 0])
        assert dt2.itemsize == 8

        dt2 = realign_dtype(dt, [0, 0, 1])
        assert dt2.itemsize == 8

        dt2 = realign_dtype(dt, [0, 0, 27])
        assert dt2.itemsize == 28


class TestUtilMode(FitsTestCase):
    """
    The high-level tests are partially covered by
    test_core.TestConvenienceFunctions.test_fileobj_mode_guessing
    but added some low-level tests as well.
    """

    def test_mode_strings(self):
        # A string signals that the file should be opened so the function
        # should return None, because it's simply not opened yet.
        assert util.fileobj_mode('tmp1.fits') is None

    @pytest.mark.skipif("not HAS_PIL")
    def test_mode_pil_image(self):
        img = np.random.randint(0, 255, (5, 5, 3)).astype(np.uint8)
        result = Image.fromarray(img)

        result.save(self.temp('test_simple.jpg'))
        # PIL doesn't support append mode. So it will allways use binary read.
        with Image.open(self.temp('test_simple.jpg')) as fileobj:
            assert util.fileobj_mode(fileobj) == 'rb'

    def test_mode_gzip(self):
        # Open a gzip in every possible (gzip is binary or "touch" only) way
        # and check if the mode was correctly identified.

        # The lists consist of tuples: filenumber, given mode, identified mode
        # The filenumber must be given because read expects the file to exist
        # and x expects it to NOT exist.
        if (version_info.major < 3 or
                (version_info.major >= 3 and version_info.minor < 4)):
            num_mode_resmode = [(0, 'a', 'ab'), (0, 'ab', 'ab'),
                                (1, 'w', 'wb'), (1, 'wb', 'wb'),
                                (1, 'r', 'rb'), (1, 'rb', 'rb')]
        else:
            # x mode was added in python 3.4
            num_mode_resmode = [(0, 'a', 'ab'), (0, 'ab', 'ab'),
                                (0, 'w', 'wb'), (0, 'wb', 'wb'),
                                (1, 'x', 'xb'),
                                (1, 'r', 'rb'), (1, 'rb', 'rb')]

        for num, mode, res in num_mode_resmode:
            filename = self.temp('test{0}.gz'.format(num))
            with gzip.GzipFile(filename, mode) as fileobj:
                assert util.fileobj_mode(fileobj) == res

    def test_mode_normal_buffering(self):
        # Use the python IO with buffering parameter. Binary mode only:

        # see "test_mode_gzip" for explanation of tuple meanings.
        if (version_info.major < 3 or
                (version_info.major >= 3 and version_info.minor < 3)):
            num_mode_resmode = [(0, 'ab', 'ab'),
                                (1, 'wb', 'wb'),
                                (1, 'rb', 'rb')]
        else:
            # x mode was added in python 3.3
            num_mode_resmode = [(0, 'ab', 'ab'),
                                (0, 'wb', 'wb'),
                                (1, 'xb', 'xb'),
                                (1, 'rb', 'rb')]
        for num, mode, res in num_mode_resmode:
            filename = self.temp('test1{0}.dat'.format(num))
            with open(filename, mode, buffering=0) as fileobj:
                assert util.fileobj_mode(fileobj) == res

    def test_mode_normal_no_buffering(self):
        # Python IO without buffering

        # see "test_mode_gzip" for explanation of tuple meanings.
        if (version_info.major < 3 or
                (version_info.major >= 3 and version_info.minor < 3)):
            num_mode_resmode = [(0, 'a', 'a'), (0, 'ab', 'ab'),
                                (1, 'w', 'w'), (2, 'wb', 'wb'),
                                (1, 'r', 'r'), (2, 'rb', 'rb')]
        else:
            # x mode was added in python 3.3
            num_mode_resmode = [(0, 'a', 'a'), (0, 'ab', 'ab'),
                                (0, 'w', 'w'), (0, 'wb', 'wb'),
                                (1, 'x', 'x'),
                                (1, 'r', 'r'), (1, 'rb', 'rb')]
        for num, mode, res in num_mode_resmode:
            filename = self.temp('test2{0}.dat'.format(num))
            with open(filename, mode) as fileobj:
                assert util.fileobj_mode(fileobj) == res

    def test_mode_normalization(self):
        # Use the normal python IO in append mode with all possible permutation
        # of the "mode" letters.

        # Tuple gives a file name suffix, the given mode and the functions
        # return. The filenumber is only for consistency with the other
        # test functions. Append can deal with existing and not existing files.
        for num, mode, res in [(0, 'a', 'a'),
                               (0, 'a+', 'a+'),
                               (0, 'ab', 'ab'),
                               (0, 'a+b', 'ab+'),
                               (0, 'ab+', 'ab+')]:
            filename = self.temp('test3{0}.dat'.format(num))
            with open(filename, mode) as fileobj:
                assert util.fileobj_mode(fileobj) == res