import sys
from tempfile import NamedTemporaryFile
from traceback import format_exception

from botocore.exceptions import ClientError, NoCredentialsError


def store_exception(exception: Exception) -> str:
    """
    Stores the exception in a temporary file and returns its filename
    """

    tracebacks = format_exception(etype=type(exception),
                                  value=exception,
                                  tb=exception.__traceback__)  # type: [str]

    content = ''.join(tracebacks)

    with NamedTemporaryFile(prefix="senza-traceback-", delete=False) as error_file:
        file_name = error_file.name
        error_file.write(content.encode())

    return file_name


def is_credentials_expired_error(client_error: ClientError) -> bool:
    """Return true if the exception's error code is ExpiredToken or RequestExpired"""
    return client_error.response['Error']['Code'] in ['ExpiredToken', 'RequestExpired']


def is_access_denied_error(e: ClientError) -> bool:
    return e.response['Error']['Code'] in ['AccessDenied']


class HandleExceptions:
    """Class HandleExceptions will display various error messages
    depending on the type of the exception and show the stacktrack for general exceptions
    depending on the value of stacktrace_visible"""

    stacktrace_visible = False

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

    def die_unknown_error(self, e: Exception):
        if not self.stacktrace_visible:
            file_name = store_exception(e)
            print('Unknown Error: {e}.\n'
                  'Please create an issue '
                  'with the content of {fn}'.format(e=e, fn=file_name),
                  file=sys.stderr)
            sys.exit(1)
        raise e

    def die_credential_error(self):
        print('No AWS credentials found. Use the "mai" command-line tool '
              'to get a temporary access key\n'
              'or manually configure either ~/.aws/credentials '
              'or AWS_ACCESS_KEY_ID/AWS_SECRET_ACCESS_KEY.',
              file=sys.stderr)
        sys.exit(1)

    def __call__(self, *args, **kwargs):
        try:
            self.function(*args, **kwargs)
        except NoCredentialsError:
            self.die_credential_error()
        except ClientError as e:
            sys.stdout.flush()
            if is_credentials_expired_error(e):
                print('AWS credentials have expired.\n'
                      'Use the "mai" command line tool to get a new'
                      ' temporary access key.',
                      file=sys.stderr)
                sys.exit(1)
            elif is_access_denied_error(e):
                self.die_credential_error()
            else:
                self.die_unknown_error(e)
        except Exception as e:
            # Catch All
            self.die_unknown_error(e)
