import asyncio
import pathlib
import aiofiles

from .attachment import attachment
from .attachment import attachment_proxy
from .aleatory_file_name import aleatory_file_name

class attachments_directory:    
    def __init__(self, directory: pathlib.Path) -> None:
        if not directory.exists() or not directory.is_dir():
            raise RuntimeError("Directory for attachments not exists.")

        self.__directory = directory

    async def store(self, content: bytes, extension: str) -> attachment_proxy:
        name = await self.__get_new_name(extension)
        path = self.directory / pathlib.Path(name)

        async with aiofiles.open(path, "wb") as handler:
            await handler.write(content)

        return attachment_proxy.create(name)

    async def change(self, file: attachment, content: bytes) -> bytes:
        before = await self.load(file)
        path = self.directory / file.resources_path
        
        async with aiofiles(path, "wb") as handler:
            handler.write(content)
    
        return before

    async def load(self, file: attachment) -> bytes:   
        path = self.directory / file.resources_path

        async with aiofiles.open(path, "rb") as handler:
            return await handler.read()

    async def remove(self, file: attachment) -> bytes:
        path = self.directory / file.resources_path
        content = await self.load(file)

        path.unlink()
        return content

    async def __get_new_name(self, extension: str) -> str:
        return await asyncio.to_thread(
            self.__get_new_name_loop, 
            extension
        )

    def __get_new_name_loop(self, extension: str) -> str:
        while True:
            new_name = aleatory_file_name(extension)
            new_path = self.directory / pathlib.Path(new_name)

            if not new_path.exists():   
                return new_name

    @property
    def directory(self) -> pathlib.Path:
        return self.__directory