# Copyright 2011 OpenStack, LLC.
# Copyright 2012 Hewlett-Packard Development Company, L.P.
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.

import os
import git
import time
import logging
import urllib

from zuul.connection import BaseConnection
from zuul.driver.git.gitmodel import GitTriggerEvent
from zuul.driver.git.gitwatcher import GitWatcher
from zuul.model import Ref, Branch


class GitConnection(BaseConnection):
    driver_name = 'git'
    log = logging.getLogger("zuul.connection.git")

    def __init__(self, driver, connection_name, connection_config):
        super(GitConnection, self).__init__(driver, connection_name,
                                            connection_config)
        if 'baseurl' not in self.connection_config:
            raise Exception('baseurl is required for git connections in '
                            '%s' % self.connection_name)
        self.baseurl = self.connection_config.get('baseurl')
        self.poll_timeout = float(
            self.connection_config.get('poll_delay', 3600 * 2))
        self.canonical_hostname = self.connection_config.get(
            'canonical_hostname')
        if not self.canonical_hostname:
            r = urllib.parse.urlparse(self.baseurl)
            if r.hostname:
                self.canonical_hostname = r.hostname
            else:
                self.canonical_hostname = 'localhost'
        self.projects = {}
        self._change_cache = {}

    def toDict(self):
        d = super().toDict()
        d.update({
            "baseurl": self.baseurl,
            "canonical_hostname": self.canonical_hostname,
        })
        return d

    def getProject(self, name):
        return self.projects.get(name)

    def addProject(self, project):
        self.projects[project.name] = project

    def getChangeFilesUpdated(self, project_name, branch, tosha):
        job = self.sched.merger.getFilesChanges(
            self.connection_name, project_name, branch, tosha)
        self.log.debug("Waiting for fileschanges job %s" % job)
        job.wait()
        if not job.updated:
            raise Exception("Fileschanges job %s failed" % job)
        self.log.debug("Fileschanges job %s got changes on files %s" %
                       (job, job.files))
        return job.files

    def lsRemote(self, project):
        refs = {}
        client = git.cmd.Git()
        output = client.ls_remote(
            "--heads", "--tags",
            os.path.join(self.baseurl, project))
        for line in output.splitlines():
            sha, ref = line.split('\t')
            if ref.startswith('refs/'):
                refs[ref] = sha
        return refs

    def maintainCache(self, relevant):
        remove = {}
        for branch, refschange in self._change_cache.items():
            for ref, change in refschange.items():
                if change not in relevant:
                    remove.setdefault(branch, []).append(ref)
        for branch, refs in remove.items():
            for ref in refs:
                del self._change_cache[branch][ref]
            if not self._change_cache[branch]:
                del self._change_cache[branch]

    def getChange(self, event, refresh=False):
        if event.ref and event.ref.startswith('refs/heads/'):
            branch = event.ref[len('refs/heads/'):]
            change = self._change_cache.get(branch, {}).get(event.newrev)
            if change:
                return change
            project = self.getProject(event.project_name)
            change = Branch(project)
            change.branch = branch
            for attr in ('ref', 'oldrev', 'newrev'):
                setattr(change, attr, getattr(event, attr))
            change.url = ""
            change.files = self.getChangeFilesUpdated(
                event.project_name, change.branch, event.oldrev)
            self._change_cache.setdefault(branch, {})[event.newrev] = change
        elif event.ref:
            # catch-all ref (ie, not a branch or head)
            project = self.getProject(event.project_name)
            change = Ref(project)
            for attr in ('ref', 'oldrev', 'newrev'):
                setattr(change, attr, getattr(event, attr))
            change.url = ""
        else:
            self.log.warning("Unable to get change for %s" % (event,))
            change = None
        return change

    def getProjectBranches(self, project, tenant):
        refs = self.lsRemote(project.name)
        branches = [ref[len('refs/heads/'):] for ref in
                    refs if ref.startswith('refs/heads/')]
        return branches

    def getGitUrl(self, project):
        return os.path.join(self.baseurl, project.name)

    def watcherCallback(self, data):
        event = GitTriggerEvent()
        event.type = 'ref-updated'
        event.timestamp = time.time()
        event.project_hostname = self.canonical_hostname
        event.project_name = data['project']
        for attr in ('ref', 'oldrev', 'newrev', 'branch_created',
                     'branch_deleted', 'branch_updated'):
            if attr in data:
                setattr(event, attr, data[attr])

        # Force changes cache update before passing
        # the event to the scheduler
        self.getChange(event)
        self.logEvent(event)
        # Pass the event to the scheduler
        self.sched.addEvent(event)

    def onLoad(self):
        self.log.debug("Starting Git Watcher")
        self._start_watcher_thread()

    def onStop(self):
        self.log.debug("Stopping Git Watcher")
        self._stop_watcher_thread()

    def _stop_watcher_thread(self):
        if self.watcher_thread:
            self.watcher_thread.stop()
            self.watcher_thread.join()

    def _start_watcher_thread(self):
        self.watcher_thread = GitWatcher(
            self,
            self.baseurl,
            self.poll_timeout,
            self.watcherCallback)
        self.watcher_thread.start()
