#!/usr/bin/python
#
# Humbug's post-receive hook.  There is a symlink
#   from /srv/git/humbug.git/hooks/post-receive
#   to   ~humbug/humbug/tools/post-receive
# on git.humbughq.com.  So to deploy changes to this script, run
#
#   ssh humbug@git.humbughq.com 'cd humbug; git pull'
#
# The "post-receive" script is run after receive-pack has accepted a pack
# and the repository has been updated.  It is passed arguments in through
# stdin in the form
#  <oldrev> <newrev> <refname>
# For example:
#  aa453216d1b3e49e7f6f98441fa56946ddcd6a20 68f7abf4e6f922807889f52bc043ecd31b79f814 refs/heads/master
#
# see contrib/hooks/ for a sample

import os
import sys
import subprocess
import time

sys.path.append(os.path.dirname(os.path.dirname(os.readlink(__file__))))
import api.common
client = api.common.HumbugAPI(email="humbug+commits@humbughq.com",
                              site="https://staging.humbughq.com",
                              api_key="xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
                              verbose=False)

def check_output(*popenargs, **kwargs):
    if 'stdout' in kwargs:
        raise ValueError('stdout argument not allowed, it will be overridden.')
    process = subprocess.Popen(stdout=subprocess.PIPE, *popenargs, **kwargs)
    output, unused_err = process.communicate()
    retcode = process.poll()
    if retcode:
        cmd = kwargs.get("args")
        if cmd is None:
            cmd = popenargs[0]
        raise subprocess.CalledProcessError(retcode, cmd, output=output)
    return output
subprocess.check_output = check_output

def update_deployment(server, oldrev, newrev, refname):
    subprocess.check_call(["ssh", server, "--", "env", "-u", "GIT_DIR",
                           "/home/humbug/humbug/tools/update-deployment",
                           oldrev, newrev, refname])

def git_commit_range(oldrev, newrev):
    log_cmd = ["git", "log", "--reverse",
               "--pretty=%aE %s", "%s..%s" % (oldrev, newrev)]
    commits = ''
    for ln in subprocess.check_output(log_cmd).splitlines():
        email, subject = ln.split(None, 1)
        # This truncation approximately fits the normal message width in the browser.
        # It would be nicer to move this into the client via CSS and a Markdown extension.
        if len(subject) > 60:
            subject = subject[:58].rstrip() + '...'
        commits += '!gravatar(%s) %s\n' % (email, subject)
    return commits

def send_bot_message(oldrev, newrev, refname):
    added   = git_commit_range(oldrev, newrev)
    removed = git_commit_range(newrev, oldrev)

    new_head = newrev[:12]
    branch   = refname.replace('refs/heads/', '')

    if removed:
        message = '`%s` was pushed to `%s`, **REMOVING**:\n\n%s' % (new_head, branch, removed)
        if added:
            message += '\n**and adding**:\n\n' + added
        message += '\n**A HISTORY REWRITE HAS OCCURRED!**'
        message += '\nPlease check your local branches to deal with this.'
    elif added:
        message = '`%s` was deployed to `%s` with:\n\n%s' % (new_head, branch, added)
    else:
        message = '`%s` was pushed to `%s`... but nothing changed?' % (new_head, branch)

    message_data = {
        "type": "stream",
        "stream": "test" if refname == "refs/heads/test-post-receive" else "devel",
        "subject": u"deploy \u21D2 " + branch,
        "content": message,
        "recipient": "tabbott@humbughq.com",
    }
    # Sleep a bit to give time for the server to restart.
    # TODO: Make this work without the sleep
    time.sleep(1)
    client.send_message(message_data)

for ln in sys.stdin:
    oldrev, newrev, refname = ln.strip().split()
    if refname in ["refs/heads/prod"]:
        send_bot_message(oldrev, newrev, refname)
        update_deployment("humbughq.com", oldrev, newrev, "origin/prod")
    elif refname in ["refs/heads/master", "refs/heads/test-post-receive"]:
        send_bot_message(oldrev, newrev, refname)
        update_deployment("staging.humbughq.com", oldrev, newrev, "origin/master")