"""Handler Utils.

=============

These are general purpose functions for use with all route handlers.

(Taken from https://github.com/theorchard/ows-project-manager/)

"""

from functools import wraps

from flask import g
from flask import request
from territories import response
from territories.validation import json_schema


def validate_header(validator):
    """Validate HTTP request headers.

    Args:
        validator (Draft3Validator): the JSON Draft3 Schema to validate
        against.

    Returns:
        callable: the wrapped function.
    """

    def decorator(function):
        @wraps(function)
        def _validate_header(*args, **kwargs):
            """Validate the request headers against a validator.

            Args:
                validator (Draft3Validator): the JSON Draft3 Schema to validate
                against.

            Returns:
                Response: error HTTP response, or continue to the calling
                function if successful.
            """
            validation_response = json_schema.validate(
                dict(request.headers), validator)
            if not validation_response:
                g.log.info(validation_response.message)
                return response.flaskify(validation_response)
            return function(*args, **kwargs)
        return _validate_header
    return decorator


def add_pagination(records, page_offset=0, page_limit=1000):
    """Wrap pagination information around records.

    Args:
        records (list): list of report dictionaries.
        page_offset (int): page offset.
        page_limit (int): total number of records per page.
    Return:
        dict: dictionary containing a list of records and pagination
            information.
    """
    return {
        'items': records[
            page_offset * page_limit: page_offset * page_limit + page_limit
        ],
        'pagination': {
            'type': 'standard',
            'offset': page_offset,
            'limit': page_limit,
            'total_records': len(records)
        }
    }