# Copyright (C) 2012-2016 Codethink Limited
#
# 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; version 2 of the License.
#
# 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, see <http://www.gnu.org/licenses/>.


import unittest
import urllib2
import os

import cliapp
import fs.memoryfs
import tempfile

import morphlib
import morphlib.gitdir_tests


class TestableRepoCache(morphlib.repocache.RepoCache):
    '''Adapts the RepoCache class for unit testing.

    All Git operations are stubbed out. You can track what Git operations have
    taken place by looking at the 'remotes' dict -- any 'clone' operations will
    set an entry in there. The 'tarballs_fetched' list tracks what tarballs
    of Git repos would have been downloaded.

    There is a single repo alias, 'example' which expands to
    git://example.com/.

    '''
    def __init__(self, update_gits=True):
        aliases = ['example=git://example.com/#example.com:%s.git']
        repo_resolver = morphlib.repoaliasresolver.RepoAliasResolver(aliases)
        tarball_base_url = 'http://lorry.example.com/tarballs'
        cachedir = '/cache/gits/'
        memoryfs = fs.memoryfs.MemoryFS()

        morphlib.repocache.RepoCache.__init__(
            self, cachedir, repo_resolver, tarball_base_url=tarball_base_url,
            custom_fs=memoryfs, update_gits=update_gits)

        self.remotes = {}
        self.tarballs_fetched = []

        self._mkdtemp_count = 0

    def _mkdtemp(self, dirname):
        thing = "foo"+str(self._mkdtemp_count)
        self._mkdtemp_count += 1
        self.fs.makedir(dirname+"/"+thing)
        return thing

    def _fetch(self, url, path):
        self.tarballs_fetched.append(url)

    def _git(self, args, **kwargs):
        if args[0] == 'clone':
            assert len(args) == 5
            remote = args[3]
            local = args[4]
            self.remotes['origin'] = {'url': remote, 'updates': 0}
            self.fs.makedir(local, recursive=True)
        elif args[0:2] == ['remote', 'set-url']:
            remote = args[2]
            url = args[3]
            self.remotes[remote] = {'url': url}
        elif args[0:2] == ['config', 'remote.origin.url']:
            remote = 'origin'
            url = args[2]
            self.remotes[remote] = {'url': url}
        elif args[0:2] == ['config', 'remote.origin.mirror']:
            remote = 'origin'
        elif args[0:2] == ['config', 'remote.origin.fetch']:
            remote = 'origin'
        else:
            raise NotImplementedError()

    def _new_cached_repo_instance(self, *args, **kwargs):
        with morphlib.gitdir_tests.allow_nonexistant_git_repos():
            repo = morphlib.cachedrepo.CachedRepo(*args, **kwargs)
            repo.update = lambda: None
            return repo

class RepoCacheTests(unittest.TestCase):

    def test_has_not_got_repo_initially(self):
        repo_cache = TestableRepoCache()
        self.assertFalse(repo_cache.has_repo('example:repo'))
        self.assertFalse(repo_cache.has_repo('git://example.com/repo'))

    def test_happily_caches_same_repo_twice(self):
        repo_cache = TestableRepoCache()
        with morphlib.gitdir_tests.allow_nonexistant_git_repos():
            repo_cache.get_updated_repo('example:repo', ref='master')
            repo_cache.get_updated_repo('example:repo', ref='master')

    def test_fails_to_cache_when_remote_does_not_exist(self):
        repo_cache = TestableRepoCache()

        def clone_fails(args, **kwargs):
            repo_cache.fs.makedir(args[4])
            raise cliapp.AppException('')
        repo_cache._git = clone_fails

        with self.assertRaises(morphlib.repocache.NoRemote):
            repo_cache.get_updated_repo('example:repo', 'master')

    def test_does_not_mind_a_missing_tarball(self):
        repo_cache = TestableRepoCache()

        def no_tarball(*args, **kwargs):
            raise cliapp.AppException('Not found')
        repo_cache._fetch = no_tarball

        with morphlib.gitdir_tests.allow_nonexistant_git_repos():
            repo_cache.get_updated_repo('example:repo', ref='master')
        self.assertEqual(repo_cache.tarballs_fetched, [])

    def test_fetches_tarball_when_it_exists(self):
        repo_url = 'git://example.com/reponame'
        repo_cache = TestableRepoCache()

        with morphlib.gitdir_tests.allow_nonexistant_git_repos():
            repo_cache.get_updated_repo(repo_url, ref='master')

        tarball_url = '%s%s.tar' % (repo_cache._tarball_base_url,
                                    repo_cache._escape(repo_url))
        self.assertEqual(repo_cache.tarballs_fetched, [tarball_url])

        # Check that the cache updated the repo after fetching the tarball.
        self.assertEqual(repo_cache.remotes['origin']['url'], repo_url)

    def test_escapes_repourl_as_filename(self):
        repo_cache = TestableRepoCache()
        escaped = repo_cache._escape('git://example.com/reponame')
        self.assertFalse('/' in escaped)

    def test_noremote_error_message_contains_repo_name(self):
        repo_url = 'git://example.com/reponame'
        e = morphlib.repocache.NoRemote(repo_url, [])
        self.assertTrue(repo_url in str(e))

    def test_avoids_caching_local_repo(self):
        repo_cache = TestableRepoCache()

        repo_cache.fs.makedir('/local/repo', recursive=True)
        cached = repo_cache.get_updated_repo('file:///local/repo', refs='master')
        assert cached.path == '/local/repo'

    def test_no_git_update_setting(self):
        repo_cache = TestableRepoCache(update_gits=False)

        with self.assertRaises(morphlib.repocache.NotCached):
            repo_cache.get_updated_repo('example:repo', ref='master')