# NOTE: these are Django new style middleware classes, won't work with
# Django < 1.10

from django.conf import settings

ACAH = [
    'Content-Type', 'X-Amz-Date', 'Authorization',
    'X-Api-Key', 'X-Amz-Security-Token', 'x-requested-with',
]

ACAM = ['DELETE', 'GET', 'OPTIONS', 'PUT', 'POST']

ACCESS_CONTROL_ALLOW_ORIGIN = getattr(
    settings, 'ACCESS_CONTROL_ALLOW_ORIGIN', '*'
)


class ApiGatewayCorsMiddleware(object):
    """
    Add CORS headers to the response. Optionally specify
    ACCESS_CONTROL_ALLOW_ORIGIN in django settings
    """

    def __init__(self, get_response):
        self.get_response = get_response

    def __call__(self, request):
        response = self.get_response(request)
        response['Access-Control-Allow-Headers'] = ','.join(ACAH)
        response['Access-Control-Allow-Methods'] = ','.join(ACAM)
        response['Access-Control-Allow-Origin'] = ACCESS_CONTROL_ALLOW_ORIGIN
        return response



COGNITO_DEBUG_CLAIMS = getattr(settings, 'COGNITO_DEBUG_CLAIMS', {})

class CognitoAuthMiddleware(object):
    """
    Attach Cognito User Pool claims to the request.
    Optionally fake claims for local development using
    COGNITO_DEBUG_CLAIMS in settings
    """
    def __init__(self, get_response):
        self.get_response = get_response

    def get_user_claims(self, request, attrs=None):
        claims = request.META.get(
            'API_GATEWAY_AUTHORIZER', {}
        ).get('claims', COGNITO_DEBUG_CLAIMS)
        if attrs:
            return {attr: claims[attr] for attr in attrs}
        return claims

    def __call__(self, request):
        claims = self.get_user_claims(request)
        # Stash claims to request
        request.authorizer_claims = claims
        response = self.get_response(request)
        return response