# This file is part of beets.
# Copyright 2016, Adrian Sampson and Diego Moreda.
#
# 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.

import codecs
import unittest

from unittest.mock import patch
from test import _common
from test.helper import TestHelper, control_stdin
from test.test_ui_importer import TerminalImportSessionSetup
from test.test_importer import ImportHelper, AutotagStub
from beets.dbcore.query import TrueQuery
from beets.library import Item
from beetsplug.edit import EditPlugin


class ModifyFileMocker:
    """Helper for modifying a file, replacing or editing its contents. Used for
    mocking the calls to the external editor during testing.
    """

    def __init__(self, contents=None, replacements=None):
        """ `self.contents` and `self.replacements` are initialized here, in
        order to keep the rest of the functions of this class with the same
        signature as `EditPlugin.get_editor()`, making mocking easier.
            - `contents`: string with the contents of the file to be used for
            `overwrite_contents()`
            - `replacement`: dict with the in-place replacements to be used for
            `replace_contents()`, in the form {'previous string': 'new string'}

        TODO: check if it can be solved more elegantly with a decorator
        """
        self.contents = contents
        self.replacements = replacements
        self.action = self.overwrite_contents
        if replacements:
            self.action = self.replace_contents

    # The two methods below mock the `edit` utility function in the plugin.

    def overwrite_contents(self, filename, log):
        """Modify `filename`, replacing its contents with `self.contents`. If
        `self.contents` is empty, the file remains unchanged.
        """
        if self.contents:
            with codecs.open(filename, 'w', encoding='utf-8') as f:
                f.write(self.contents)

    def replace_contents(self, filename, log):
        """Modify `filename`, reading its contents and replacing the strings
        specified in `self.replacements`.
        """
        with codecs.open(filename, 'r', encoding='utf-8') as f:
            contents = f.read()
        for old, new_ in self.replacements.items():
            contents = contents.replace(old, new_)
        with codecs.open(filename, 'w', encoding='utf-8') as f:
            f.write(contents)


class EditMixin:
    """Helper containing some common functionality used for the Edit tests."""
    def assertItemFieldsModified(self, library_items, items, fields=[],  # noqa
                                 allowed=['path']):
        """Assert that items in the library (`lib_items`) have different values
        on the specified `fields` (and *only* on those fields), compared to
        `items`.

        An empty `fields` list results in asserting that no modifications have
        been performed. `allowed` is a list of field changes that are ignored
        (they may or may not have changed; the assertion doesn't care).
        """
        for lib_item, item in zip(library_items, items):
            diff_fields = [field for field in lib_item._fields
                           if lib_item[field] != item[field]]
            self.assertEqual(set(diff_fields).difference(allowed),
                             set(fields))

    def run_mocked_interpreter(self, modify_file_args={}, stdin=[]):
        """Run the edit command during an import session, with mocked stdin and
        yaml writing.
        """
        m = ModifyFileMocker(**modify_file_args)
        with patch('beetsplug.edit.edit', side_effect=m.action):
            with control_stdin('\n'.join(stdin)):
                self.importer.run()

    def run_mocked_command(self, modify_file_args={}, stdin=[], args=[]):
        """Run the edit command, with mocked stdin and yaml writing, and
        passing `args` to `run_command`."""
        m = ModifyFileMocker(**modify_file_args)
        with patch('beetsplug.edit.edit', side_effect=m.action):
            with control_stdin('\n'.join(stdin)):
                self.run_command('edit', *args)


@_common.slow_test()
@patch('beets.library.Item.write')
class EditCommandTest(unittest.TestCase, TestHelper, EditMixin):
    """Black box tests for `beetsplug.edit`. Command line interaction is
    simulated using `test.helper.control_stdin()`, and yaml editing via an
    external editor is simulated using `ModifyFileMocker`.
    """
    ALBUM_COUNT = 1
    TRACK_COUNT = 10

    def setUp(self):
        self.setup_beets()
        self.load_plugins('edit')
        # Add an album, storing the original fields for comparison.
        self.album = self.add_album_fixture(track_count=self.TRACK_COUNT)
        self.album_orig = {f: self.album[f] for f in self.album._fields}
        self.items_orig = [{f: item[f] for f in item._fields} for
                           item in self.album.items()]

    def tearDown(self):
        EditPlugin.listeners = None
        self.teardown_beets()
        self.unload_plugins()

    def assertCounts(self, mock_write, album_count=ALBUM_COUNT, track_count=TRACK_COUNT,  # noqa
                     write_call_count=TRACK_COUNT, title_starts_with=''):
        """Several common assertions on Album, Track and call counts."""
        self.assertEqual(len(self.lib.albums()), album_count)
        self.assertEqual(len(self.lib.items()), track_count)
        self.assertEqual(mock_write.call_count, write_call_count)
        self.assertTrue(all(i.title.startswith(title_starts_with)
                            for i in self.lib.items()))

    def test_title_edit_discard(self, mock_write):
        """Edit title for all items in the library, then discard changes."""
        # Edit track titles.
        self.run_mocked_command({'replacements': {'t\u00eftle':
                                                  'modified t\u00eftle'}},
                                # Cancel.
                                ['c'])

        self.assertCounts(mock_write, write_call_count=0,
                          title_starts_with='t\u00eftle')
        self.assertItemFieldsModified(self.album.items(), self.items_orig, [])

    def test_title_edit_apply(self, mock_write):
        """Edit title for all items in the library, then apply changes."""
        # Edit track titles.
        self.run_mocked_command({'replacements': {'t\u00eftle':
                                                  'modified t\u00eftle'}},
                                # Apply changes.
                                ['a'])

        self.assertCounts(mock_write, write_call_count=self.TRACK_COUNT,
                          title_starts_with='modified t\u00eftle')
        self.assertItemFieldsModified(self.album.items(), self.items_orig,
                                      ['title', 'mtime'])

    def test_single_title_edit_apply(self, mock_write):
        """Edit title for one item in the library, then apply changes."""
        # Edit one track title.
        self.run_mocked_command({'replacements': {'t\u00eftle 9':
                                                  'modified t\u00eftle 9'}},
                                # Apply changes.
                                ['a'])

        self.assertCounts(mock_write, write_call_count=1,)
        # No changes except on last item.
        self.assertItemFieldsModified(list(self.album.items())[:-1],
                                      self.items_orig[:-1], [])
        self.assertEqual(list(self.album.items())[-1].title,
                         'modified t\u00eftle 9')

    def test_noedit(self, mock_write):
        """Do not edit anything."""
        # Do not edit anything.
        self.run_mocked_command({'contents': None},
                                # No stdin.
                                [])

        self.assertCounts(mock_write, write_call_count=0,
                          title_starts_with='t\u00eftle')
        self.assertItemFieldsModified(self.album.items(), self.items_orig, [])

    def test_album_edit_apply(self, mock_write):
        """Edit the album field for all items in the library, apply changes.
        By design, the album should not be updated.""
        """
        # Edit album.
        self.run_mocked_command({'replacements': {'\u00e4lbum':
                                                  'modified \u00e4lbum'}},
                                # Apply changes.
                                ['a'])

        self.assertCounts(mock_write, write_call_count=self.TRACK_COUNT)
        self.assertItemFieldsModified(self.album.items(), self.items_orig,
                                      ['album', 'mtime'])
        # Ensure album is *not* modified.
        self.album.load()
        self.assertEqual(self.album.album, '\u00e4lbum')

    def test_single_edit_add_field(self, mock_write):
        """Edit the yaml file appending an extra field to the first item, then
        apply changes."""
        # Append "foo: bar" to item with id == 2. ("id: 1" would match both
        # "id: 1" and "id: 10")
        self.run_mocked_command({'replacements': {"id: 2":
                                                  "id: 2\nfoo: bar"}},
                                # Apply changes.
                                ['a'])

        self.assertEqual(self.lib.items('id:2')[0].foo, 'bar')
        # Even though a flexible attribute was written (which is not directly
        # written to the tags), write should still be called since templates
        # might use it.
        self.assertCounts(mock_write, write_call_count=1,
                          title_starts_with='t\u00eftle')

    def test_a_album_edit_apply(self, mock_write):
        """Album query (-a), edit album field, apply changes."""
        self.run_mocked_command({'replacements': {'\u00e4lbum':
                                                  'modified \u00e4lbum'}},
                                # Apply changes.
                                ['a'],
                                args=['-a'])

        self.album.load()
        self.assertCounts(mock_write, write_call_count=self.TRACK_COUNT)
        self.assertEqual(self.album.album, 'modified \u00e4lbum')
        self.assertItemFieldsModified(self.album.items(), self.items_orig,
                                      ['album', 'mtime'])

    def test_a_albumartist_edit_apply(self, mock_write):
        """Album query (-a), edit albumartist field, apply changes."""
        self.run_mocked_command({'replacements': {'album artist':
                                                  'modified album artist'}},
                                # Apply changes.
                                ['a'],
                                args=['-a'])

        self.album.load()
        self.assertCounts(mock_write, write_call_count=self.TRACK_COUNT)
        self.assertEqual(self.album.albumartist, 'the modified album artist')
        self.assertItemFieldsModified(self.album.items(), self.items_orig,
                                      ['albumartist', 'mtime'])

    def test_malformed_yaml(self, mock_write):
        """Edit the yaml file incorrectly (resulting in a malformed yaml
        document)."""
        # Edit the yaml file to an invalid file.
        self.run_mocked_command({'contents': '!MALFORMED'},
                                # Edit again to fix? No.
                                ['n'])

        self.assertCounts(mock_write, write_call_count=0,
                          title_starts_with='t\u00eftle')

    def test_invalid_yaml(self, mock_write):
        """Edit the yaml file incorrectly (resulting in a well-formed but
        invalid yaml document)."""
        # Edit the yaml file to an invalid but parseable file.
        self.run_mocked_command({'contents': 'wellformed: yes, but invalid'},
                                # No stdin.
                                [])

        self.assertCounts(mock_write, write_call_count=0,
                          title_starts_with='t\u00eftle')


@_common.slow_test()
class EditDuringImporterTest(TerminalImportSessionSetup, unittest.TestCase,
                             ImportHelper, TestHelper, EditMixin):
    """TODO
    """
    IGNORED = ['added', 'album_id', 'id', 'mtime', 'path']

    def setUp(self):
        self.setup_beets()
        self.load_plugins('edit')
        # Create some mediafiles, and store them for comparison.
        self._create_import_dir(3)
        self.items_orig = [Item.from_path(f.path) for f in self.media_files]
        self.matcher = AutotagStub().install()
        self.matcher.matching = AutotagStub.GOOD
        self.config['import']['timid'] = True

    def tearDown(self):
        EditPlugin.listeners = None
        self.unload_plugins()
        self.teardown_beets()
        self.matcher.restore()

    def test_edit_apply_asis(self):
        """Edit the album field for all items in the library, apply changes,
        using the original item tags.
        """
        self._setup_import_session()
        # Edit track titles.
        self.run_mocked_interpreter({'replacements': {'Tag Title':
                                                      'Edited Title'}},
                                    # eDit, Apply changes.
                                    ['d', 'a'])

        # Check that only the 'title' field is modified.
        self.assertItemFieldsModified(self.lib.items(), self.items_orig,
                                      ['title'],
                                      self.IGNORED + ['albumartist',
                                                      'mb_albumartistid'])
        self.assertTrue(all('Edited Title' in i.title
                            for i in self.lib.items()))

        # Ensure album is *not* fetched from a candidate.
        self.assertEqual(self.lib.albums()[0].mb_albumid, '')

    def test_edit_discard_asis(self):
        """Edit the album field for all items in the library, discard changes,
        using the original item tags.
        """
        self._setup_import_session()
        # Edit track titles.
        self.run_mocked_interpreter({'replacements': {'Tag Title':
                                                      'Edited Title'}},
                                    # eDit, Cancel, Use as-is.
                                    ['d', 'c', 'u'])

        # Check that nothing is modified, the album is imported ASIS.
        self.assertItemFieldsModified(self.lib.items(), self.items_orig,
                                      [],
                                      self.IGNORED + ['albumartist',
                                                      'mb_albumartistid'])
        self.assertTrue(all('Tag Title' in i.title
                            for i in self.lib.items()))

        # Ensure album is *not* fetched from a candidate.
        self.assertEqual(self.lib.albums()[0].mb_albumid, '')

    def test_edit_apply_candidate(self):
        """Edit the album field for all items in the library, apply changes,
        using a candidate.
        """
        self._setup_import_session()
        # Edit track titles.
        self.run_mocked_interpreter({'replacements': {'Applied Title':
                                                      'Edited Title'}},
                                    # edit Candidates, 1, Apply changes.
                                    ['c', '1', 'a'])

        # Check that 'title' field is modified, and other fields come from
        # the candidate.
        self.assertTrue(all('Edited Title ' in i.title
                            for i in self.lib.items()))
        self.assertTrue(all('match ' in i.mb_trackid
                            for i in self.lib.items()))

        # Ensure album is fetched from a candidate.
        self.assertIn('albumid', self.lib.albums()[0].mb_albumid)

    def test_edit_retag_apply(self):
        """Import the album using a candidate, then retag and edit and apply
        changes.
        """
        self._setup_import_session()
        self.run_mocked_interpreter({},
                                    # 1, Apply changes.
                                    ['1', 'a'])

        # Retag and edit track titles.  On retag, the importer will reset items
        # ids but not the db connections.
        self.importer.paths = []
        self.importer.query = TrueQuery()
        self.run_mocked_interpreter({'replacements': {'Applied Title':
                                                      'Edited Title'}},
                                    # eDit, Apply changes.
                                    ['d', 'a'])

        # Check that 'title' field is modified, and other fields come from
        # the candidate.
        self.assertTrue(all('Edited Title ' in i.title
                            for i in self.lib.items()))
        self.assertTrue(all('match ' in i.mb_trackid
                            for i in self.lib.items()))

        # Ensure album is fetched from a candidate.
        self.assertIn('albumid', self.lib.albums()[0].mb_albumid)

    def test_edit_discard_candidate(self):
        """Edit the album field for all items in the library, discard changes,
        using a candidate.
        """
        self._setup_import_session()
        # Edit track titles.
        self.run_mocked_interpreter({'replacements': {'Applied Title':
                                                      'Edited Title'}},
                                    # edit Candidates, 1, Apply changes.
                                    ['c', '1', 'a'])

        # Check that 'title' field is modified, and other fields come from
        # the candidate.
        self.assertTrue(all('Edited Title ' in i.title
                            for i in self.lib.items()))
        self.assertTrue(all('match ' in i.mb_trackid
                            for i in self.lib.items()))

        # Ensure album is fetched from a candidate.
        self.assertIn('albumid', self.lib.albums()[0].mb_albumid)

    def test_edit_apply_asis_singleton(self):
        """Edit the album field for all items in the library, apply changes,
        using the original item tags and singleton mode.
        """
        self._setup_import_session(singletons=True)
        # Edit track titles.
        self.run_mocked_interpreter({'replacements': {'Tag Title':
                                                      'Edited Title'}},
                                    # eDit, Apply changes, aBort.
                                    ['d', 'a', 'b'])

        # Check that only the 'title' field is modified.
        self.assertItemFieldsModified(self.lib.items(), self.items_orig,
                                      ['title'],
                                      self.IGNORED + ['albumartist',
                                                      'mb_albumartistid'])
        self.assertTrue(all('Edited Title' in i.title
                            for i in self.lib.items()))

    def test_edit_apply_candidate_singleton(self):
        """Edit the album field for all items in the library, apply changes,
        using a candidate and singleton mode.
        """
        self._setup_import_session()
        # Edit track titles.
        self.run_mocked_interpreter({'replacements': {'Applied Title':
                                                      'Edited Title'}},
                                    # edit Candidates, 1, Apply changes, aBort.
                                    ['c', '1', 'a', 'b'])

        # Check that 'title' field is modified, and other fields come from
        # the candidate.
        self.assertTrue(all('Edited Title ' in i.title
                            for i in self.lib.items()))
        self.assertTrue(all('match ' in i.mb_trackid
                            for i in self.lib.items()))


def suite():
    return unittest.TestLoader().loadTestsFromName(__name__)

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