"""API Utility Functions.

Functions to support generating API Responses.
"""

from copy import deepcopy

from oto import status as response_code
from oto.response import create_error_response
from oto.response import Response

from backend.constants import api as api_consts
from backend.constants import error as error_consts
from backend.constants import field as field_consts


def create_get_list_response(items, status=response_code.OK):
    """Create get items response.

    Wraps item list in pagination API list.

    NOTE: Pagination isn't supported, this will need to be implemented if
    needed in the future.

    Args:
        items (list): List of objects
        status (int): HTTP response status code

    Returns:
        Response object
    """
    total_records = len(items)

    message = {
        'items': items,
        'pagination': {
            'type': api_consts.PAGINATION_TYPE_NONE,
            'total_records': total_records
        }
    }

    return Response(message=message, status=status)


def create_get_nested_lists_response(lists, status=response_code.OK, key_name='items'):
    """Create get items response.

    Wraps item nested lists in pagination API list.

    NOTE: Pagination isn't supported, this will need to be implemented if
    needed in the future.

    Args:
        lists (list): List of lists of objects
        status (int): HTTP response status code
        key_name (str): A key name: items, tracks...

    Returns:
        Response object
    """
    message = [{key_name: sublist} for sublist in lists]

    return Response(message=message, status=status)


def create_validation_response(items, errors, warnings=None):
    """Create track validation response.

    Args:
        items (list): List of unique entity objects
        errors (list): List of errors keyed by entity objects
        warnings (list): List of warnings keyed by entity objects

    Returns:
        Response object
    """
    base_data = {
        field_consts.TOTAL_TRACKS: len(items),
        field_consts.VALID_TRACKS: len(items) - len(errors),
        field_consts.ERRORS: errors,
        field_consts.MESSAGE_VALID: False if len(errors) else True
    }
    if warnings:
        base_data[field_consts.WARNINGS] = warnings

    return Response(base_data)


def create_ok_response():
    """Create status 200 OK response."""
    return Response()


def create_validation_error_response(
        message=error_consts.VALIDATION_ERROR_MSG, *args):
    """Create validation error response.

    Args:
        message (str): Message for error
        *args: List of args to pass when formatting message
    """
    return create_error_response(
        code=error_consts.VALIDATION_ERROR_CODE,
        message=message.format(*args))


def copy_response(response):
    """Copy response object.

    Args:
        response (Response): Response object

    Return:
        Response
    """
    return Response(
        status=response.status, message=deepcopy(response.message),
        errors=deepcopy(response.errors))


def create_isrc_validation_response(items, count, products=None, status=response_code.OK,):
    """Create track validation response.
    Args:
        items (list): List of unique entity objects
        errors (list): List of errors keyed by entity objects
        warnings (list): List of warnings keyed by entity objects
    Returns:
        Response object
    """
    base_data = {
        field_consts.TOTAL_PRODUCTS: len(items),
        field_consts.TOTAL_PRODUCT_ISSUES: count,
        field_consts.PRODUCTS: products,
        field_consts.MESSAGE_VALID: False if len(products) else True
    }

    return Response(status=status, message=base_data)