import boto.s3.connection
import bunch
import itertools
import os
import random
import string
import yaml

s3 = bunch.Bunch()
config = bunch.Bunch()
prefix = ''

bucket_counter = itertools.count(1)
key_counter = itertools.count(1)

def choose_bucket_prefix(template, max_len=30):
    """
    Choose a prefix for our test buckets, so they're easy to identify.

    Use template and feed it more and more random filler, until it's
    as long as possible but still below max_len.
    """
    rand = ''.join(
        random.choice(string.ascii_lowercase + string.digits)
        for c in range(255)
        )

    while rand:
        s = template.format(random=rand)
        if len(s) <= max_len:
            return s
        rand = rand[:-1]

    raise RuntimeError(
        'Bucket prefix template is impossible to fulfill: {template!r}'.format(
            template=template,
            ),
        )

def nuke_bucket(bucket):
    try:
        bucket.set_canned_acl('private')
        # TODO: deleted_cnt and the while loop is a work around for rgw
        # not sending the
        deleted_cnt = 1
        while deleted_cnt:
            deleted_cnt = 0
            for key in bucket.list():
                print 'Cleaning bucket {bucket} key {key}'.format(
                    bucket=bucket,
                    key=key,
                    )
                key.set_canned_acl('private')
                key.delete()
                deleted_cnt += 1
        bucket.delete()
    except boto.exception.S3ResponseError as e:
        # TODO workaround for buggy rgw that fails to send
        # error_code, remove
        if (e.status == 403
            and e.error_code is None
            and e.body == ''):
            e.error_code = 'AccessDenied'
        if e.error_code != 'AccessDenied':
            print 'GOT UNWANTED ERROR', e.error_code
            raise
        # seems like we're not the owner of the bucket; ignore
        pass

def nuke_prefixed_buckets():
    for name, conn in s3.items():
        print 'Cleaning buckets from connection {name}'.format(name=name)
        for bucket in conn.get_all_buckets():
            if bucket.name.startswith(prefix):
                print 'Cleaning bucket {bucket}'.format(bucket=bucket)
                nuke_bucket(bucket)

    print 'Done with cleanup of test buckets.'

def read_config(fp):
    config = bunch.Bunch()
    g = yaml.safe_load_all(fp)
    for new in g:
        config.update(bunch.bunchify(new))
    return config

def connect(conf):
    mapping = dict(
        port='port',
        host='host',
        is_secure='is_secure',
        access_key='aws_access_key_id',
        secret_key='aws_secret_access_key',
        )
    kwargs = dict((mapping[k],v) for (k,v) in conf.iteritems() if k in mapping)
    #process calling_format argument
    calling_formats = dict(
        ordinary=boto.s3.connection.OrdinaryCallingFormat(),
        subdomain=boto.s3.connection.SubdomainCallingFormat(),
        vhost=boto.s3.connection.VHostCallingFormat(),
        )
    kwargs['calling_format'] = calling_formats['ordinary']
    if conf.has_key('calling_format'):
        raw_calling_format = conf['calling_format']
        try:
            kwargs['calling_format'] = calling_formats[raw_calling_format]
        except KeyError:
            raise RuntimeError(
                'calling_format unknown: %r' % raw_calling_format
                )
    # TODO test vhost calling format
    conn = boto.s3.connection.S3Connection(**kwargs)
    return conn

def setup():
    global s3, config, prefix
    s3.clear()
    config.clear()

    try:
        path = os.environ['S3TEST_CONF']
    except KeyError:
        raise RuntimeError(
            'To run tests, point environment '
            + 'variable S3TEST_CONF to a config file.',
            )
    with file(path) as f:
        config.update(read_config(f))

    # These 3 should always be present.
    if 's3' not in config:
        raise RuntimeError('Your config file is missing the s3 section!')
    if 'defaults' not in config.s3:
        raise RuntimeError('Your config file is missing the s3.defaults section!')
    if 'fixtures' not in config:
        raise RuntimeError('Your config file is missing the fixtures section!')

    template = config.fixtures.get('bucket prefix', 'test-{random}-')
    prefix = choose_bucket_prefix(template=template)
    if prefix == '':
        raise RuntimeError("Empty Prefix! Aborting!")

    defaults = config.s3.defaults
    for section in config.s3.keys():
        if section == 'defaults':
            continue

        conf = {}
        conf.update(defaults)
        conf.update(config.s3[section])
        conn = connect(conf)
        s3[section] = conn

    # WARNING! we actively delete all buckets we see with the prefix
    # we've chosen! Choose your prefix with care, and don't reuse
    # credentials!

    # We also assume nobody else is going to use buckets with that
    # prefix. This is racy but given enough randomness, should not
    # really fail.
    nuke_prefixed_buckets()

def get_new_bucket(connection=None):
    """
    Get a bucket that exists and is empty.

    Always recreates a bucket from scratch. This is useful to also
    reset ACLs and such.
    """
    if connection is None:
        connection = s3.main
    name = '{prefix}{num}'.format(
        prefix=prefix,
        num=next(bucket_counter),
        )
    # the only way for this to fail with a pre-existing bucket is if
    # someone raced us between setup nuke_prefixed_buckets and here;
    # ignore that as astronomically unlikely
    bucket = connection.create_bucket(name)
    return bucket

def teardown():
    nuke_prefixed_buckets()