import requests
from flask import current_app


class DocumentDownloadError(Exception):
    def __init__(self, message, status_code):
        super().__init__(message, status_code)
        self.message = message
        self.status_code = status_code

    @classmethod
    def from_exception(cls, e):
        message = e.response.json()["error"]
        status_code = e.response.status_code
        return cls(message, status_code)


class DocumentDownloadClient:
    def init_app(self, app):
        self.api_host = app.config["DOCUMENT_DOWNLOAD_API_HOST"]
        self.auth_token = app.config["DOCUMENT_DOWNLOAD_API_KEY"]

    def get_upload_url(self, service_id):
        return "{}/services/{}/documents".format(self.api_host, service_id)

    def upload_document(self, service_id, file_contents, is_csv=None):
        try:
            response = requests.post(
                self.get_upload_url(service_id),
                headers={
                    "Authorization": "Bearer {}".format(self.auth_token),
                },
                json={
                    "document": file_contents,
                    "is_csv": is_csv or False,
                },
                timeout=30,
            )

            response.raise_for_status()
        except requests.RequestException as e:
            # if doc dl responds with a non-400, (eg 403) it's referring to credentials that the API and Doc DL use.
            # we don't want to tell users about that, so anything that isn't a 400 (virus scan failed or file type
            # unrecognised) should be raised as a 500 internal server error here.
            if e.response is None:
                raise Exception(f"Unhandled document download error: {repr(e)}")
            elif e.response.status_code == 400:
                error = DocumentDownloadError.from_exception(e)
                current_app.logger.info(
                    "Document download request failed with error: {}".format(
                        error.message
                    )
                )
                raise error
            else:
                raise Exception(f"Unhandled document download error: {e.response.text}")

        return response.json()["document"]["url"]