"""Event Handler."""

from content_utils.exceptions import InvalidMessageException

from src import config
from src.connectors import get_graphql_connector
from src.connectors import get_os_connector
from src.exceptions import ReviewQueueItemExplicitSkip


def event_handler(msg_body):
    """Event handling."""
    _validate_message(msg_body, ['operation'])
    _check_explicit_skip(msg_body)
    if msg_body['operation'] == 'update':
        update_in_index(msg_body)
        return 'Patched index'
    elif msg_body['operation'] == 'delete':
        delete_from_index(msg_body)
        return 'Removed from index'
    elif msg_body['operation'] == 'add':
        add_to_index(msg_body)
        return 'Added to index'
    raise InvalidMessageException(f'Unhandled operation: {msg_body["operation"]}')


def _validate_message(msg_body, fields):
    for field in fields:
        if not msg_body.get(field):
            raise InvalidMessageException(f'missing "{field}" in message body')


def _check_explicit_skip(msg_body):
    """Skip explicitly listed review queue items."""
    review_queue_id = msg_body.get('review_queue_id')
    if review_queue_id in config.SKIP_REVIEW_QUEUE_ITEMS:
        raise ReviewQueueItemExplicitSkip(
            f'Explicit Skip: review_queue_id={review_queue_id}')


def update_in_index(msg_body):
    """Update an indexed product."""
    _validate_message(msg_body, ['product_id', 'review_queue_id'])
    product_info = get_graphql_connector().get_indexable_product({
        'product_id': msg_body['product_id'],
        'review_queue_id': msg_body['review_queue_id']
    })
    get_os_connector().patch_product(product_info)


def delete_from_index(msg_body):
    """Remove an indexed product."""
    _validate_message(msg_body, ['product_id'])
    get_os_connector().remove_product(msg_body['product_id'])


def add_to_index(msg_body):
    """Add an indexed product."""
    _validate_message(msg_body, ['product_id', 'review_queue_id'])
    index_record = get_graphql_connector().get_indexable_product({
        'product_id': msg_body['product_id'],
        'review_queue_id': msg_body['review_queue_id']
    })
    get_os_connector().index_product(index_record)