from datetime import datetime, timedelta

from azure.storage.blob import BlobSasPermissions, generate_blob_sas

from azurebatchload.checks import Checks


class Base(Checks):
    def __init__(
        self,
        destination,
        folder,
        extension=None,
        modified_since=None,
        method="batch",
        list_files=None,
        expiry_download_links=7,
    ):
        super().__init__(directory=folder)

        self.destination = destination
        self.folder = folder
        self.extension = extension
        self.modified_since = modified_since
        if not self._check_azure_cli_installed():
            self.method = "single"
        else:
            self.method = method
        self.list_files = list_files
        credentials = self._check_connection_credentials()
        self.connection_string = credentials[0]
        self.account_name = credentials[1]
        self.account_key = credentials[2]
        self.expiry_download_links = expiry_download_links

    def checks(self):
        allowed_methods = ("batch", "single")
        if self.method not in allowed_methods:
            raise ValueError(f"Method {self.method} is not a valid method. Choose from {' or '.join(allowed_methods)}.")

        if self.list_files and self.method == "batch":
            raise ValueError("list_files is only allowed with method='single'.")

        if self.list_files and not isinstance(self.list_files, list):
            raise ValueError(f"Argument list_files was set, but is not of type list, but type {type(self.list_files)}")

    def create_blob_link(self, blob_folder, blob_name) -> str:
        if blob_folder:
            full_path_blob = f"{blob_folder}/{blob_name}"
        else:
            full_path_blob = blob_name
        url = f"https://{self.account_name}.blob.core.windows.net/{self.destination}/{full_path_blob}"
        sas_token = generate_blob_sas(
            account_name=self.account_name,
            account_key=self.account_key,
            container_name=self.destination,
            blob_name=full_path_blob,
            permission=BlobSasPermissions(read=True, delete_previous_version=False),
            expiry=datetime.utcnow() + timedelta(days=self.expiry_download_links),
        )

        url_with_sas = f"{url}?{sas_token}"
        return url_with_sas

    @staticmethod
    def create_not_case_sensitive_extension(extension):
        """
        We create in-case sensitive fnmatch
        .pdf -> .[Pp][Dd][Ff]
        .csv -> .[Cc][Ss][Vv]
        """
        new_extension = ""
        for letter in extension:
            if not letter.isalpha():
                new_extension += letter
            else:
                new_extension += f"[{letter.upper()}{letter}]"

        if not new_extension.startswith("*"):
            new_extension = "*" + new_extension

        return new_extension

    def define_pattern(self):
        self.extension = self.create_not_case_sensitive_extension(self.extension)
        if self.folder and not self.extension:
            if self.folder.endswith("/"):
                pattern = self.folder + "*"
            else:
                pattern = self.folder + "/*"
        elif self.folder and self.extension:
            pattern = self.folder.rstrip("/") + "/" + "*" + self.extension
        elif not self.folder and self.extension:
            pattern = "*" + self.extension
        else:
            pattern = None

        return pattern