# This file is part of Buildbot.  Buildbot 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.
#
# 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.
#
# Copyright Buildbot Team Members
from __future__ import absolute_import

from datetime import datetime

from twisted.internet import defer
from twisted.python import log
from zorg.buildbot.status.txgithub.api import GithubApi as GitHubAPI
from zope.interface import implements

from buildbot import config
from buildbot.interfaces import IStatusReceiver
from buildbot.process.properties import WithProperties
from buildbot.status.base import StatusReceiverMultiService
from buildbot.status.builder import FAILURE
from buildbot.status.builder import SUCCESS

_STATE_MAP = {
    SUCCESS: 'success',
    FAILURE: 'failure',
}

def _getGitHubState(results):
    """
    Convert Buildbot states into GitHub states.
    """
    # GitHub defines `success`, `failure` and `error` states.
    # We explicitly map success and failure. Any other BuildBot status
    # is converted to `error`.
    return _STATE_MAP.get(results, 'error')


def _human_readable_delta(start, end):
    """
    Return a string of human readable time delta.
    """
    start_date = datetime.fromtimestamp(start)
    end_date = datetime.fromtimestamp(end)
    delta = end_date - start_date

    result = []
    if delta.days > 0:
        result.append('%d days' % (delta.days,))
    if delta.seconds > 0:
        hours = delta.seconds / 3600
        if hours > 0:
            result.append('%d hours' % (hours,))
        minutes = (delta.seconds - hours * 3600) / 60
        if minutes:
            result.append('%d minutes' % (minutes,))
        seconds = delta.seconds % 60
        if seconds > 0:
            result.append('%d seconds' % (seconds,))

    if result:
        return ', '.join(result)
    else:
        return 'super fast'


class GitHubStatus(StatusReceiverMultiService):
    """
    Send build status to GitHub.

    For more details see Buildbot's user manual.
    """

    implements(IStatusReceiver)

    def __init__(self, token, repoOwner, repoName,
                 builders_to_report=None, # None to report all builders.
                 sha=None,
                 startDescription=None, endDescription=None,
                 baseURL=None):
        """
        Token for GitHub API.
        """
        if not GitHubAPI:
            config.error('GitHubStatus requires txgithub package installed')

        StatusReceiverMultiService.__init__(self)

        self._builders_to_report = builders_to_report
        self._sha = sha or WithProperties("%(got_revision)s")
        self._repoOwner = repoOwner
        self._repoName = repoName
        self._startDescription = startDescription or "Build started."
        self._endDescription = endDescription

        self._github = GitHubAPI(oauth2_token=token, baseURL=baseURL)

        self._status = None

    def startService(self):
        StatusReceiverMultiService.startService(self)
        self._status = self.parent.getStatus()
        self._status.subscribe(self)
        log.msg("GitHubStatus: Service started.")

    def stopService(self):
        StatusReceiverMultiService.stopService(self)
        self._status.unsubscribe(self)
        log.msg("GitHubStatus: Service stopped.")

    def builderAdded(self, name_, builder_):
        """
        Subscribe to all builders.
        """
        if self._builders_to_report and (name_ not in self._builders_to_report):
            return None

        log.msg("GitHubStatus: Subscribed for %s builder notifications." % (name_,))
        return self

    def buildStarted(self, builderName, build):
        """
        See: C{IStatusReceiver}.
        """
        if self._builders_to_report and (builderName not in self._builders_to_report):
            # Build started on a builder we do not care of.
            return # skip unless white listed

        #log.msg("GitHubStatus: Build started on %s (%s). Do not report the build start." % (builderName, build))
        # TODO: Do we want to report a build start? This depends on if we want to report a bot errors/terminations as a possible build outcome.
        #d = self._sendStartStatus(builderName, build)
        #d.addErrback(log.err,
        #             'GitHubStatus: While sending start status to GitHub for %s.' %
        #             (builderName,))

    @defer.inlineCallbacks
    def _sendStartStatus(self, builderName, build):
        """
        Send start status to GitHub.
        """
        status = yield self._getGitHubRepoProperties(build)
        if not status:
            defer.returnValue(None)

        startTime, _ = build.getTimes()

        description = yield build.render(self._startDescription)

        status.update({
            'state': 'pending',
            'description': description,
            'builderName': builderName,
            'startDateTime': datetime.fromtimestamp(startTime).isoformat(' '),
            'endDateTime': 'In progress',
            'duration': 'In progress',
        })
        result = yield self._sendGitHubStatus(status)
        defer.returnValue(result)

    def buildFinished(self, builderName, build, results):
        """
        See: C{IStatusReceiver}.
        """
        if self._builders_to_report and (builderName not in self._builders_to_report):
            # Build finished on a builder we do not care of.
            return # skip unless white listed

        # For now we report only properly completed builds without buildbot errors.
        if results != SUCCESS and results != FAILURE:
            return # skip error builds

        d = self._sendFinishStatus(builderName, build, results)
        d.addErrback(log.err,
                     'GitHubStatus: While sending finish status to GitHub for %s.' %
                     (builderName,))

    @defer.inlineCallbacks
    def _sendFinishStatus(self, builderName, build, results):
        """
        Send status to GitHub at end of builder execution.
        """
        repoOwner = build.render(self._repoOwner)
        repoName = build.render(self._repoName)
        sha = build.render(self._sha)

        status = {
            'repoOwner': repoOwner,
            'repoName': repoName,
            'sha': sha,
            'targetURL': self._status.getURLForThing(build),
            'buildNumber': str(build.getNumber()),
        }

        state = _getGitHubState(results)
        startTime, endTime = build.getTimes()
        duration = _human_readable_delta(startTime, endTime)
        description = build.render(self._endDescription or 'Elapsed %s.' % duration)

        status.update({
            'state': state,
            'description': description,
            'builderName': builderName,
            'startDateTime': datetime.fromtimestamp(startTime).isoformat(' '),
            'endDateTime': datetime.fromtimestamp(endTime).isoformat(' '),
            'duration': duration,
        })

        result = yield self._sendGitHubStatus(status)
        defer.returnValue(result)

    @defer.inlineCallbacks
    def _getGitHubRepoProperties(self, build):
        """
        Return a dictionary with GitHub related properties from `build`.
        """
        repoOwner, repoName, sha = yield defer.gatherResults([
            build.render(self._repoOwner),
            build.render(self._repoName),
            build.render(self._sha),
        ])

        if not repoOwner or not repoName:
            defer.returnValue({})

        if not sha:
            log.msg('GitHubStatus: No revision found.')
            defer.returnValue({})

        result = {
            'repoOwner': repoOwner,
            'repoName': repoName,
            'sha': sha,
            'targetURL': self._status.getURLForThing(build),
            'buildNumber': str(build.getNumber()),
        }
        defer.returnValue(result)

    def _sendGitHubStatus(self, status):
        """
        Send status to GitHub API.
        """
        d = self._github.repos.createStatus(
            repo_user=status['repoOwner'].encode('utf-8'),
            repo_name=status['repoName'].encode('utf-8'),
            sha=status['sha'].encode('utf-8'),
            state=status['state'].encode('utf-8'),
            target_url=status['targetURL'].encode('utf-8'),
            description=status['description'].encode('utf-8'),
            context=status['builderName'].encode('utf-8'),
        )

        success_message = (
            'GitHubStatus: Status "%(state)s" sent for '
            '%(repoOwner)s/%(repoName)s at %(sha)s.'
        ) % status
        error_message = (
            'GitHubStatus: Fail to send status "%(state)s" for '
            '%(repoOwner)s/%(repoName)s at %(sha)s.'
        ) % status
        d.addCallback(lambda result: log.msg(success_message))
        d.addErrback(lambda failure: log.err(failure, error_message))
        return d