# -*- coding: utf-8 -*-
'''
Connection module for Amazon DynamoDB

.. versionadded:: 2015.5.0

:configuration: This module accepts explicit DynamoDB credentials but can also
    utilize IAM roles assigned to the instance through Instance Profiles.
    Dynamic credentials are then automatically obtained from AWS API and no
    further configuration is necessary. More Information available at:

    .. code-block:: text

        http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/iam-roles-for-amazon-ec2.html

    If IAM roles are not used you need to specify them either in a pillar or
    in the minion's config file:

    .. code-block:: yaml

        keyid: GKTADJGHEIQSXMKKRBJ08H
        key: askdjghsdfjkghWupUjasdflkdfklgjsdfjajkghs

    A region may also be specified in the configuration:

    .. code-block:: yaml

        region: us-east-1

    If a region is not specified, the default is us-east-1.

    It's also possible to specify key, keyid and region via a profile, either
    as a passed in dict, or as a string to pull from pillars or minion config:

    .. code-block:: yaml

        myprofile:
            keyid: GKTADJGHEIQSXMKKRBJ08H
            key: askdjghsdfjkghWupUjasdflkdfklgjsdfjajkghs
            region: us-east-1

:depends: boto
'''
# keep lint from choking on _get_conn and _cache_id
#pylint: disable=E0602

# Import Python libs
from __future__ import absolute_import
import logging
import time

logger = logging.getLogger(__name__)
logging.getLogger('boto').setLevel(logging.INFO)

# Import third party libs
import salt.ext.six as six
from salt.ext.six.moves import range  # pylint: disable=import-error,redefined-builtin
try:
    #pylint: disable=unused-import
    import boto
    import boto.dynamodb2
    #pylint: enable=unused-import
    from boto.dynamodb2.fields import HashKey, RangeKey
    from boto.dynamodb2.fields import AllIndex, GlobalAllIndex
    from boto.dynamodb2.table import Table
    from boto.exception import JSONResponseError
    HAS_BOTO = True
except ImportError:
    HAS_BOTO = False


def __virtual__():
    '''
    Only load if boto libraries exist.
    '''
    if not HAS_BOTO:
        return (False, 'The module boto_dynamodb could not be loaded: boto libraries not found')
    __utils__['boto.assign_funcs'](__name__, 'dynamodb2', pack=__salt__)
    return True


def create_table(table_name, region=None, key=None, keyid=None, profile=None,
                 read_capacity_units=None, write_capacity_units=None,
                 hash_key=None, hash_key_data_type=None, range_key=None,
                 range_key_data_type=None, local_indexes=None,
                 global_indexes=None):
    '''
    Creates a DynamoDB table.

    CLI Example:

    .. code-block:: bash

        salt myminion boto_dynamodb.create_table table_name /
        region=us-east-1 /
        hash_key=id /
        hash_key_data_type=N /
        range_key=created_at /
        range_key_data_type=N /
        read_capacity_units=1 /
        write_capacity_units=1
    '''
    schema = []
    primary_index_fields = []
    primary_index_name = ''
    if hash_key:
        hash_key_obj = HashKey(hash_key, data_type=hash_key_data_type)
        schema.append(hash_key_obj)
        primary_index_fields.append(hash_key_obj)
        primary_index_name += hash_key
    if range_key:
        range_key_obj = RangeKey(range_key, data_type=range_key_data_type)
        schema.append(range_key_obj)
        primary_index_fields.append(range_key_obj)
        primary_index_name += '_'
        primary_index_name += range_key
    primary_index_name += '_index'
    throughput = {
        'read':     read_capacity_units,
        'write':    write_capacity_units
    }
    local_table_indexes = []
    if local_indexes:
        for index in local_indexes:
            local_table_indexes.append(_extract_index(index))
    global_table_indexes = []
    if global_indexes:
        for index in global_indexes:
            global_table_indexes.append(
                _extract_index(index, global_index=True)
            )

    conn = _get_conn(region=region, key=key, keyid=keyid, profile=profile)

    Table.create(
        table_name,
        schema=schema,
        throughput=throughput,
        indexes=local_table_indexes,
        global_indexes=global_table_indexes,
        connection=conn
    )

    # Table creation can take several seconds to propagate.
    # We will check MAX_ATTEMPTS times.
    MAX_ATTEMPTS = 30
    for i in range(MAX_ATTEMPTS):
        if exists(
            table_name,
            region,
            key,
            keyid,
            profile
        ):
            return True
        else:
            time.sleep(1)   # sleep for one second and try again
    return False


def exists(table_name, region=None, key=None, keyid=None, profile=None):
    '''
    Check to see if a table exists.

    CLI Example:

    .. code-block:: bash

        salt myminion boto_dynamodb.exists table_name region=us-east-1
    '''
    try:
        conn = _get_conn(region=region, key=key, keyid=keyid, profile=profile)
        conn.describe_table(table_name)
    except JSONResponseError as e:
        if e.error_code == 'ResourceNotFoundException':
            return False
        raise

    return True


def delete(table_name, region=None, key=None, keyid=None, profile=None):
    '''
    Delete a DynamoDB table.

    CLI Example:

    .. code-block:: bash

        salt myminion boto_dynamodb.delete table_name region=us-east-1
    '''
    conn = _get_conn(region=region, key=key, keyid=keyid, profile=profile)

    table = Table(table_name, connection=conn)
    table.delete()

    # Table deletion can take several seconds to propagate.
    # We will retry MAX_ATTEMPTS times.
    MAX_ATTEMPTS = 30
    for i in range(MAX_ATTEMPTS):
        if not exists(table_name, region, key, keyid, profile):
            return True
        else:
            time.sleep(1)   # sleep for one second and try again
    return False


def update(table_name, throughput=None, global_indexes=None,
           region=None, key=None, keyid=None, profile=None):
    '''
    Update a DynamoDB table.

    CLI example::

        salt myminion boto_dynamodb.update table_name region=us-east-1
    '''
    conn = _get_conn(region=region, key=key, keyid=keyid, profile=profile)
    table = Table(table_name, connection=conn)
    return table.update(throughput=throughput, global_indexes=global_indexes)


def describe(table_name, region=None, key=None, keyid=None, profile=None):
    '''
    Describe a DynamoDB table.

    CLI example::

        salt myminion boto_dynamodb.describe table_name region=us-east-1
    '''
    conn = _get_conn(region=region, key=key, keyid=keyid, profile=profile)
    table = Table(table_name, connection=conn)
    return table.describe()


def _extract_index(index_data, global_index=False):
    '''
    Instantiates and returns an AllIndex object given a valid index
    configuration
    '''
    parsed_data = {}
    keys = []

    for key, value in six.iteritems(index_data):
        for item in value:
            for field, data in six.iteritems(item):
                if field == 'hash_key':
                    parsed_data['hash_key'] = data
                elif field == 'hash_key_data_type':
                    parsed_data['hash_key_data_type'] = data
                elif field == 'range_key':
                    parsed_data['range_key'] = data
                elif field == 'range_key_data_type':
                    parsed_data['range_key_data_type'] = data
                elif field == 'name':
                    parsed_data['name'] = data
                elif field == 'read_capacity_units':
                    parsed_data['read_capacity_units'] = data
                elif field == 'write_capacity_units':
                    parsed_data['write_capacity_units'] = data

    if parsed_data['hash_key']:
        keys.append(
            HashKey(
                parsed_data['hash_key'],
                data_type=parsed_data['hash_key_data_type']
            )
        )
    if parsed_data['range_key']:
        keys.append(
            RangeKey(
                parsed_data['range_key'],
                data_type=parsed_data['range_key_data_type']
            )
        )
    if (
            global_index and
            parsed_data['read_capacity_units'] and
            parsed_data['write_capacity_units']):
        parsed_data['throughput'] = {
            'read':     parsed_data['read_capacity_units'],
            'write':    parsed_data['write_capacity_units']
        }
    if parsed_data['name'] and len(keys) > 0:
        if global_index:
            return GlobalAllIndex(
                parsed_data['name'],
                parts=keys,
                throughput=parsed_data['throughput']
            )
        else:
            return AllIndex(
                parsed_data['name'],
                parts=keys
            )
