# Copyright (C) 2017-2019  The Software Heritage developers
# See the AUTHORS file at the top-level directory of this distribution
# License: GNU General Public License version 3, or any later version
# See top-level LICENSE file for more information

"""Module in charge of providing the standard sword errors

"""

from rest_framework import status
from django.shortcuts import render


FORBIDDEN = 'forbidden'
UNAUTHORIZED = 'unauthorized'
NOT_FOUND = 'unknown'
BAD_REQUEST = 'bad-request'
ERROR_CONTENT = 'error-content'
CHECKSUM_MISMATCH = 'checksum-mismatch'
MEDIATION_NOT_ALLOWED = 'mediation-not-allowed'
METHOD_NOT_ALLOWED = 'method-not-allowed'
MAX_UPLOAD_SIZE_EXCEEDED = 'max_upload_size_exceeded'
PARSING_ERROR = 'parsing-error'


class ParserError(ValueError):
    """Specific parsing error detected when parsing the xml metadata input

    """
    pass


ERRORS = {
    FORBIDDEN: {
        'status': status.HTTP_403_FORBIDDEN,
        'iri': 'http://purl.org/net/sword/error/ErrorForbidden',
        'tag': 'sword:ErrorForbidden',
    },
    UNAUTHORIZED: {
        'status': status.HTTP_401_UNAUTHORIZED,
        'iri': 'http://purl.org/net/sword/error/ErrorUnauthorized',
        'tag': 'sword:ErrorUnauthorized',
    },
    NOT_FOUND: {
        'status': status.HTTP_404_NOT_FOUND,
        'iri': 'http://purl.org/net/sword/error/ErrorNotFound',
        'tag': 'sword:ErrorNotFound',
    },
    ERROR_CONTENT: {
        'status': status.HTTP_415_UNSUPPORTED_MEDIA_TYPE,
        'iri': 'http://purl.org/net/sword/error/ErrorContent',
        'tag': 'sword:ErrorContent',
    },
    CHECKSUM_MISMATCH: {
        'status': status.HTTP_412_PRECONDITION_FAILED,
        'iri': 'http://purl.org/net/sword/error/ErrorChecksumMismatch',
        'tag': 'sword:ErrorChecksumMismatch',
    },
    BAD_REQUEST: {
        'status': status.HTTP_400_BAD_REQUEST,
        'iri': 'http://purl.org/net/sword/error/ErrorBadRequest',
        'tag': 'sword:ErrorBadRequest',
    },
    PARSING_ERROR: {
        'status': status.HTTP_400_BAD_REQUEST,
        'iri': 'http://purl.org/net/sword/error/ErrorBadRequest',
        'tag': 'sword:ErrorBadRequest',
    },
    MEDIATION_NOT_ALLOWED: {
        'status': status.HTTP_412_PRECONDITION_FAILED,
        'iri': 'http://purl.org/net/sword/error/MediationNotAllowed',
        'tag': 'sword:MediationNotAllowed',
    },
    METHOD_NOT_ALLOWED: {
        'status': status.HTTP_405_METHOD_NOT_ALLOWED,
        'iri': 'http://purl.org/net/sword/error/MethodNotAllowed',
        'tag': 'sword:MethodNotAllowed',
    },
    MAX_UPLOAD_SIZE_EXCEEDED: {
        'status': status.HTTP_413_REQUEST_ENTITY_TOO_LARGE,
        'iri': 'http://purl.org/net/sword/error/MaxUploadSizeExceeded',
        'tag': 'sword:MaxUploadSizeExceeded',
    },
}


def make_error_dict(key, summary=None, verbose_description=None):
    """Utility function to factorize error message dictionary.

    Args:
        key (str): Error status key referenced in swh.deposit.errors module
        summary (str/None): Error message clarifying the status
        verbose_description (str/None): A more verbose
          description or work around a potential problem.

    Returns:
        Dictionary with key 'error' detailing the 'status' and
        associated 'message'

    """
    return {
        'error': {
            'key': key,
            'summary': summary,
            'verboseDescription': verbose_description,
        },
    }


def make_error_response_from_dict(req, error):
    """Utility function to return an http response with error detail.

    Args:
        req (Request): original request
        error (dict): Error described as dict, typically generated
        from the make_error_dict function.

    Returns:
        HttpResponse with detailed error.

    """
    error_information = ERRORS[error['key']]
    context = error
    context.update(error_information)
    return render(req, 'deposit/error.xml',
                  context=error,
                  content_type='application/xml',
                  status=error_information['status'])


def make_error_response(req, key, summary=None, verbose_description=None):
    """Utility function to create an http response with detailed error.

    Args:
        req (Request): original request
        key (str): Error status key referenced in swh.deposit.errors module
        summary (str): Error message clarifying the status
        verbose_description (str / None): A more verbose
          description or work around a potential problem.

    Returns:
        Dictionary with key 'error' detailing the 'status' and
        associated 'message'

    """
    error = make_error_dict(key, summary, verbose_description)
    return make_error_response_from_dict(req, error['error'])