#!/usr/bin/python
from yaml.error import YAMLError
import argparse
import getpass
import json
import os
import socket
import subprocess
import sys
import urllib2 as urllib
import uuid
import yaml

def parse_args():
    desc = """
Process a git push by running it through the buildpack process

Note this script must be run as the `git` user.
"""
    parser = argparse.ArgumentParser(description=desc,
                                     formatter_class=argparse.RawDescriptionHelpFormatter)
    parser.add_argument('src', action='store',
                        help='path to source repository')
    parser.add_argument('user', action='store',
                        help='name of user who started build',
                        default='system')
    # check execution environment
    if getpass.getuser() != 'git':
        sys.stderr.write('This script must be run as the "git" user\n')
        parser.print_help()
        sys.exit(1)
    args = parser.parse_args()
    args.src = os.path.abspath(args.src)
    # store formation ID
    args.formation = '/'.join(args.src.split(os.path.sep)[-1:]).replace('.git', '')
    return args

def _sizeof_fmt(num):
    for x in ['bytes','KB','MB','GB','TB']:
        if num < 1024.0:
            return "%3.1f %s" % (num, x)
        num /= 1024.0

def puts_step(s):
    sys.stdout.write("-----> %s\n" % s)
    sys.stdout.flush()

def puts_line():
    sys.stdout.write("\n")
    sys.stdout.flush()

def puts(s):
    sys.stdout.write("       " + s)
    sys.stdout.flush()

def exit_on_error(error_code, msg):
    sys.stderr.write(msg)
    sys.stderr.write('\n')
    sys.stderr.flush()
    sys.exit(error_code)
    
if __name__ == '__main__':
    args = parse_args()
    # get sha of master
    with open(os.path.join(args.src, 'refs/heads/master')) as f:
        sha = f.read().strip('\n')
    # prepare for buildpack run
    slug_path = os.path.join('<%= @slug_dir %>', '{0}-{1}.tar.gz'.format(args.formation, sha))
    tag = uuid.uuid4().hex[:4]
    image = '{0}:{1}'.format(args.formation, tag)
    try:
        # build/compile
        cmd = 'git archive master | <%= @buildstep_dir %>/buildstep {0} {1}'.format(args.formation, tag)
        p = subprocess.Popen(cmd, cwd=args.src, shell=True)
        rc = p.wait()
        if rc != 0:
            exit_on_error(rc, 'Build failed, leaving current release in place')
        # extract slug
        cmd = 'docker run {0} tar -C / -cz app > {1}'.format(image, slug_path)
        p = subprocess.Popen(cmd, cwd=args.src, shell=True)
        rc = p.wait()
        if rc != 0:
            exit_on_error(rc, 'Could not extract slug from {0}'.format(image))
        # extract procfile
        cmd = 'docker run {0} cat /app/Procfile'.format(image)
        p = subprocess.Popen(cmd, cwd=args.src, shell=True, stdout=subprocess.PIPE)
        rc = p.wait()
        if rc != 0:
            exit_on_error(rc, 'Could not extract Procfile from {0}'.format(image))
        try:
            procfile = yaml.safe_load(p.stdout.read())
        except YAMLError as e:
            exit_on_error(1, 'Invalid Procfile format: {0}'.format(e))
        # release
        cmd = 'docker run {0} /build/release'.format(image)
        p = subprocess.Popen(cmd, cwd=args.src, shell=True, stdout=subprocess.PIPE)
        rc = p.wait()
        if rc != 0:
            exit_on_error(rc, 'Release failed, leaving current release in place')
        try:
            release = yaml.safe_load(p.stdout.read())
        except YAMLError as e:
            exit_on_error(1, 'Invalid release format: {0}'.format(e))
    finally:
        p = subprocess.Popen(['docker', 'rmi', image], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        rc = p.wait()
        if rc != 0:
            exit_on_error(rc, 'Warning: could not clean up image {0}'.format(image))
    # calculate checksum
    p = subprocess.Popen(['sha256sum', slug_path], stdout=subprocess.PIPE)
    rc = p.wait()
    if rc != 0:
        exit_on_error(rc, 'Could not calculate SHA of slug')
    checksum = p.stdout.read().split(' ')[0]
    # run
    build = {'formation': args.formation, 'sha': sha, 'checksum': checksum}
    build['config'] = release.get('config_vars', {})
    # TODO: replace with actual user
    build['ssh_key'] = args.user
    # TODO: figure out better controller fqdn lookup or switch to mandatory S3 hosting
    ip = json.loads(urllib.urlopen('http://jsonip.com').read())['ip']
    fqdn = socket.gethostbyaddr(ip)[0]
    build['url'] = "http://{fqdn}/slugs/{args.formation}-{sha}.tar.gz".format(**locals())
    build['procfile'] = procfile
    # calculate slug size
    build['size'] = os.stat(slug_path).st_size
    puts_line()
    puts_step("Compiled slug size: %s" % _sizeof_fmt(build['size']))
    # run
    sys.stdout.write("       " + "Launching... ")
    sys.stdout.flush()
    p = subprocess.Popen(['sudo', '-u', 'deis', '<%= @controller_dir %>/bin/build-release-run'], 
                         stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    stdout, stderr = p.communicate(json.dumps(build))
    rc = p.wait()
    if rc != 0:
        raise RuntimeError('Build creation error {0}'.format(stderr))
    databag = json.loads(stdout)
    sys.stdout.write("done\n")
    sys.stdout.flush()
    puts_line()
    puts_step("{args.formation} deployed to Deis".format(**locals()))
    proxies = databag['nodes']['proxies'].values()
    if proxies:
        for proxy_fqdn in proxies:
            puts("http://{proxy_fqdn}\n".format(**locals()))
    else:
        puts('No proxies found, use `deis scale proxies=N backends=N` to scale your formation\n\n')