#!/usr/bin/python
#
# Gerrit Launchpad and CIA Hook, inspired by:
#   https://github.com/hobbs/jirret
#   http://cia.vc/clients/git/ciabot.bash
#   http://cia.vc/clients/bzr/cia_bzr.py
#
# Copyright (C) 2011, 2012 Catalyst IT (http://www.catalyst.net.nz)
#
# 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 3 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, see <http://www.gnu.org/licenses/>.

from email.mime.text import MIMEText
from getopt import getopt
import re
import smtplib
import subprocess
import sys
from xml.dom.minidom import Document
import xmlrpclib

FROM_ADDRESS = 'dev@mahara.org'
TO_ADDRESS_SUFFIX = '@bugs.launchpad.net'
CIA_PROJECT = 'Mahara'
CIA_SERVER = 'http://cia.vc'
BASE_DIR = '/home/gerrit/mahara_reviews'

def send_notifications(change_url, project, branch, submitter, commit):
    # Extract git log of all merged commits
    git_log = subprocess.Popen(['git', '--git-dir=' + BASE_DIR + '/git/' + project + '.git', 'log', '--no-merges', commit + '^1..' + commit], stdout=subprocess.PIPE).communicate()[0]

    # Find bug numbers referenced in the git log
    bug_regexp = '[Bb]ug:? *#?([0-9]+)'
    tokens = re.split(bug_regexp, git_log)

    # Extract unique bug numbers
    bugs = []
    for token in tokens:
        if re.match('^\d+$', token) and (token not in bugs):
            bugs.append(token)
            send_bug_mail(token, change_url, project, commit, submitter, branch, git_log)

    submit_to_cia(project, commit, branch, git_log)

def send_bug_mail(bug_number, change_url, project, commit, submitter, branch, git_log):

    to_address = bug_number + TO_ADDRESS_SUFFIX

    gitorious_url = 'http://gitorious.org/mahara/%s/commit/%s' % (project, commit)
    body = '''Reviewed:  %s
Committed: %s
Submitter: %s
Branch:    %s\n''' % (change_url, gitorious_url, submitter, branch)

    msg = MIMEText(body + '\n' + git_log)
    msg['Subject'] = 'A change has been merged'
    msg['From'] = FROM_ADDRESS
    msg['To'] = to_address

    s = smtplib.SMTP()
    s.connect()
    s.sendmail(FROM_ADDRESS, [to_address], msg.as_string())
    s.quit()

def append_commit(commits, document, project, full_commit_id, author, log):
    if not full_commit_id or not author:
        return

    revision = subprocess.Popen(['git', '--git-dir=' + BASE_DIR + '/git/' + project + '.git', 'rev-parse', '--short', full_commit_id], stdout=subprocess.PIPE).communicate()[0].strip()

    gitorious_url = 'http://gitorious.org/mahara/%s/commit/%s' % (project, full_commit_id)
    commit = document.createElement('commit')

    commit_author = document.createElement('author')
    commit_author.appendChild(document.createTextNode(author))
    commit.appendChild(commit_author)

    commit_revision = document.createElement('revision')
    commit_revision.appendChild(document.createTextNode(revision))
    commit.appendChild(commit_revision)

    commit_log = document.createElement('log')
    commit_log.appendChild(document.createTextNode(log))
    commit.appendChild(commit_log)

    commit_url = document.createElement('url')
    commit_url.appendChild(document.createTextNode(gitorious_url))
    commit.appendChild(commit_url)

    commits.append(commit)

def generate_commits(document, project, git_log):
    commits = []
    commit_id = author = log = None
    for line in git_log.splitlines():
        if line.startswith('commit'):
            append_commit(commits, document, project, commit_id, author, log)
            commit_id = line[7:]
            author = log = None
        elif line.startswith('Author:'):
            full_author = line[8:]
            author = re.search('^(.+) <[^>]+>$', full_author).group(1)
        elif line.startswith('    ') and not log:
            log = line[4:]

    append_commit(commits, document, project, commit_id, author, log)
    return commits

def submit_to_cia(project, commit, branch, git_log):
    doc = Document()
    message = doc.createElement('message')
    generator = doc.createElement('generator')
    generator_name = doc.createElement('name')
    generator_name.appendChild(doc.createTextNode('Mahara custom CIA script'))
    generator_version = doc.createElement('version')
    generator_version.appendChild(doc.createTextNode('1.0'))
    generator_url = doc.createElement('url')
    generator_url.appendChild(doc.createTextNode('http://gitorious.org/mahara/mahara-scripts/blobs/master/change-merged'))
    generator.appendChild(generator_name)
    generator.appendChild(generator_version)
    generator.appendChild(generator_url)
    message.appendChild(generator)

    source = doc.createElement('source')
    source_project = doc.createElement('project')
    source_project.appendChild(doc.createTextNode(CIA_PROJECT))
    source_branch = doc.createElement('branch')
    source_branch.appendChild(doc.createTextNode(branch))
    source.appendChild(source_project)
    source.appendChild(source_branch)
    message.appendChild(source)

    body = doc.createElement('body')
    message.appendChild(body)
    doc.appendChild(message)

    for commit in generate_commits(doc, project, git_log):
        body.appendChild(commit)
        xmlrpclib.ServerProxy(CIA_SERVER).hub.deliver(doc.toxml())
        body.removeChild(commit)

def main():
    # https://gerrit.googlecode.com/svn/documentation/2.1.6/config-hooks.html#change-merged
    gerrit_args = ['change=', 'change-url=', 'project=', 'branch=', 'submitter=', 'commit=']
    args, unused = getopt(sys.argv[1:], '', gerrit_args)

    change_url = project = branch = submitter = commit = None
    for argname, argv in args:
        if argname == '--change-url':
            change_url = argv
        elif argname == '--project':
            project = argv
        elif argname == '--branch':
            branch = argv
        elif argname == '--submitter':
            submitter = argv
        elif argname == '--commit':
            commit = argv

    if change_url and project and branch and submitter and commit:
        send_notifications(change_url, project, branch, submitter, commit)
    else:
        print 'Missing arguments'
	return 1

    return 0;

if __name__ == '__main__':
    sys.exit(main())