import ftplib
import posixpath
from typing import AsyncIterator

from async_generator import aclosing

from ._aftplib import AFTP


async def download_text(server: str, user: str, password: str, path: str,
                        encoding='cp1252', n_attempts: int = 10) -> AsyncIterator[str]:
    nlines_sent = 0
    for attempt in range(n_attempts):
        ftp = AFTP(server, user, password)
        await ftp.connect()
        filename = posixpath.basename(path)
        path = posixpath.dirname(path)
        if path:
            await ftp.cwd(path)
        nlines_captured = 0
        try:
            async with aclosing(ftp.iretrlines(f"RETR '{filename}'")) as _iterator:
                async for line in _iterator:
                    nlines_captured += 1
                    if nlines_captured <= nlines_sent:
                        continue
                    nlines_sent += 1
                    yield line.decode(encoding)
        except ftplib.error_temp as e:
            if '426-Data transfer timeout, aborted' not in e.args[0]:
                raise
        else:
            break
    else:
        raise Exception(f'Failed {n_attempts} attempts, cancelling')