# Copyright (C) 2008, 2009, 2012, 2016 Canonical Ltd
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

from io import BytesIO

from .. import errors, filters
from ..filters import (
    ContentFilter,
    ContentFilterContext,
    filtered_input_file,
    filtered_output_bytes,
    _get_filter_stack_for,
    _get_registered_names,
    internal_size_sha_file_byname,
    )
from ..osutils import sha_string
from . import TestCase, TestCaseInTempDir


# sample filter stacks
def _swapcase(chunks, context=None):
    return [s.swapcase() for s in chunks]


def _addjunk(chunks):
    return [b'junk\n'] + [s for s in chunks]


def _deljunk(chunks, context):
    return [s for s in chunks[1:]]


_stack_1 = [
    ContentFilter(_swapcase, _swapcase),
    ]
_stack_2 = [
    ContentFilter(_swapcase, _swapcase),
    ContentFilter(_addjunk, _deljunk),
    ]

# sample data
_sample_external = [b'Hello\n', b'World\n']
_internal_1 = [b'hELLO\n', b'wORLD\n']
_internal_2 = [b'junk\n', b'hELLO\n', b'wORLD\n']


class TestContentFilterContext(TestCase):

    def test_empty_filter_context(self):
        ctx = ContentFilterContext()
        self.assertEqual(None, ctx.relpath())

    def test_filter_context_with_path(self):
        ctx = ContentFilterContext('foo/bar')
        self.assertEqual('foo/bar', ctx.relpath())


class TestFilteredInput(TestCase):

    def test_filtered_input_file(self):
        # test an empty stack returns the same result
        external = b''.join(_sample_external)
        f = BytesIO(external)
        (fileobj, size) = filtered_input_file(f, [])
        self.assertEqual((external, 12), (fileobj.read(), size))
        # test a single item filter stack
        f = BytesIO(external)
        expected = b''.join(_internal_1)
        (fileobj, size) = filtered_input_file(f, _stack_1)
        self.assertEqual((expected, 12), (fileobj.read(), size))
        # test a multi item filter stack
        f = BytesIO(external)
        expected = b''.join(_internal_2)
        (fileobj, size) = filtered_input_file(f, _stack_2)
        self.assertEqual((expected, 17), (fileobj.read(), size))


class TestFilteredOutput(TestCase):

    def test_filtered_output_bytes(self):
        # test an empty stack returns the same result
        self.assertEqual(_sample_external, list(filtered_output_bytes(
            _sample_external, None)))
        # test a single item filter stack
        self.assertEqual(_sample_external, list(filtered_output_bytes(
            _internal_1, _stack_1)))
        # test a multi item filter stack
        self.assertEqual(_sample_external, list(filtered_output_bytes(
            _internal_2, _stack_2)))


class TestFilteredSha(TestCaseInTempDir):

    def test_filtered_size_sha(self):
        # check that the size and sha matches what's expected
        text = b'Foo Bar Baz\n'
        with open('a', 'wb') as a:
            a.write(text)
        post_filtered_content = b''.join(_swapcase([text], None))
        expected_len = len(post_filtered_content)
        expected_sha = sha_string(post_filtered_content)
        self.assertEqual((expected_len, expected_sha),
                         internal_size_sha_file_byname(
                             'a', [ContentFilter(_swapcase, _swapcase)]))


class TestFilterStackMaps(TestCase):

    def _register_map(self, pref, stk1, stk2):
        def stk_lookup(key):
            return {'v1': stk1, 'v2': stk2}.get(key)
        filters.filter_stacks_registry.register(pref, stk_lookup)

    def test_filter_stack_maps(self):
        # Save the current registry
        original_registry = filters._reset_registry()
        self.addCleanup(filters._reset_registry, original_registry)
        # Test registration
        a_stack = [ContentFilter('b', 'c')]
        z_stack = [ContentFilter('y', 'x'), ContentFilter('w', 'v')]
        self._register_map('foo', a_stack, z_stack)
        self.assertEqual(['foo'], _get_registered_names())
        self._register_map('bar', z_stack, a_stack)
        self.assertEqual(['bar', 'foo'], _get_registered_names())
        # Test re-registration raises an error
        self.assertRaises(KeyError, self._register_map,
                          'foo', [], [])

    def test_get_filter_stack_for(self):
        # Save the current registry
        original_registry = filters._reset_registry()
        self.addCleanup(filters._reset_registry, original_registry)
        # Test filter stack lookup
        a_stack = [ContentFilter('b', 'c')]
        d_stack = [ContentFilter('d', 'D')]
        z_stack = [ContentFilter('y', 'x'), ContentFilter('w', 'v')]
        self._register_map('foo', a_stack, z_stack)
        self._register_map('bar', d_stack, z_stack)
        prefs = (('foo', 'v1'),)
        self.assertEqual(a_stack, _get_filter_stack_for(prefs))
        prefs = (('foo', 'v2'),)
        self.assertEqual(z_stack, _get_filter_stack_for(prefs))
        prefs = (('foo', 'v1'), ('bar', 'v1'))
        self.assertEqual(a_stack + d_stack, _get_filter_stack_for(prefs))
        # Test an unknown preference
        prefs = (('baz', 'v1'),)
        self.assertEqual([], _get_filter_stack_for(prefs))
        # Test an unknown value
        prefs = (('foo', 'v3'),)
        self.assertEqual([], _get_filter_stack_for(prefs))
        # Test a value of None is skipped
        prefs = (('foo', None), ('bar', 'v1'))
        self.assertEqual(d_stack, _get_filter_stack_for(prefs))