#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# deploy-it is the script we use to deploy changes to our N1 backend systems.
# it tags releases automatically and helps prevent obvious mistakes like
# deploying a non-production branch to our prod infra.
import sys
import subprocess

if len(sys.argv) != 2:
    print "deploy-it is the script we use to deploy changes to our N1 backend systems."
    print "usage: deploy-it environment"
    sys.exit(-1)

environment = sys.argv[1]
level = 'prod'
if 'staging' in environment:
    level = 'staging'
elif 'dev' in environment:
    level = 'dev'

branch = subprocess.check_output('git rev-parse --abbrev-ref HEAD'.split()).strip()

if level == 'prod' and branch != 'production':
    sys.exit("Deploys to production environments must be made from the 'production' "
             "branch.")

if level == 'prod':
    print "Fetching latest repo data."
    # this can fail for all sorts of reasons; best to just let a human
    # deal with any errors
    try:
        subprocess.check_call(['git', 'pull'])
    except:
        sys.exit("`git pull` failed — can't proceed.")

# Tag the deploy so that we know exactly what has been deployed by whom.
short_commit = subprocess.check_output('git rev-parse --short HEAD'.split()).strip()
username = subprocess.check_output(['whoami']).strip()
tag_name = "{}-{}-{}".format(short_commit, environment, username)

# Check if the tag already exists.
if subprocess.call(['git', 'rev-parse', '-q', '--verify', tag_name]) != 0:
    # If not create it.
    try:
        subprocess.check_call(['git', 'tag', '-a', tag_name, '-m', "'{}'".format(tag_name)])
        subprocess.check_call(['git', 'push', 'origin', tag_name])
    except:
        sys.exit("Unable to create and save tag — won't proceed.")

# Hand things off to `eb deploy`. It will push a tagged release to EB.
try:
    subprocess.check_call(['eb', 'deploy', environment])
except:
    sys.exit("eb deploy failed!")