"""SFTP файловый менеджер."""
from __future__ import annotations

import stat
from dataclasses import dataclass
from pathlib import PurePosixPath
from typing import Callable, List, Optional

import asyncssh

from app.core.ssh import SSHClient


@dataclass
class FileEntry:
    name: str
    path: str
    is_dir: bool
    size: int
    mtime: float
    permissions: str


def _fmt_perms(mode: int) -> str:
    return stat.filemode(mode) if mode else "?"


async def list_dir(c: SSHClient, path: str) -> List[FileEntry]:
    async with c.conn.start_sftp_client() as sftp:
        entries = []
        try:
            attrs = await sftp.readdir(path)
        except asyncssh.SFTPFailure as e:
            raise PermissionError(str(e))
        for a in attrs:
            if a.filename in (".", ".."):
                continue
            full = str(PurePosixPath(path) / a.filename)
            is_dir = stat.S_ISDIR(a.attrs.permissions or 0)
            entries.append(
                FileEntry(
                    name=a.filename,
                    path=full,
                    is_dir=is_dir,
                    size=a.attrs.size or 0,
                    mtime=a.attrs.mtime or 0,
                    permissions=_fmt_perms(a.attrs.permissions or 0),
                )
            )
        entries.sort(key=lambda e: (not e.is_dir, e.name.lower()))
        return entries


async def download(c: SSHClient, remote: str, local: str,
                   progress: Optional[Callable[[int, int], None]] = None) -> None:
    async with c.conn.start_sftp_client() as sftp:
        size = (await sftp.stat(remote)).size or 0
        done = 0
        async with sftp.open(remote, "rb") as rf, open(local, "wb") as lf:
            while True:
                chunk = await rf.read(65536)
                if not chunk:
                    break
                lf.write(chunk)
                done += len(chunk)
                if progress:
                    progress(done, size)


async def upload(c: SSHClient, local: str, remote: str,
                 progress: Optional[Callable[[int, int], None]] = None) -> None:
    import os
    size = os.path.getsize(local)
    done = 0
    async with c.conn.start_sftp_client() as sftp:
        async with sftp.open(remote, "wb") as rf, open(local, "rb") as lf:
            while True:
                chunk = lf.read(65536)
                if not chunk:
                    break
                await rf.write(chunk)
                done += len(chunk)
                if progress:
                    progress(done, size)


async def delete(c: SSHClient, path: str, is_dir: bool) -> None:
    async with c.conn.start_sftp_client() as sftp:
        if is_dir:
            await c.run(f"rm -rf {path!r}")
        else:
            await sftp.remove(path)


async def mkdir(c: SSHClient, path: str) -> None:
    async with c.conn.start_sftp_client() as sftp:
        await sftp.makedirs(path, exist_ok=True)


async def rename(c: SSHClient, old: str, new: str) -> None:
    async with c.conn.start_sftp_client() as sftp:
        await sftp.rename(old, new)


async def read_text(c: SSHClient, path: str, limit: int = 500_000) -> str:
    async with c.conn.start_sftp_client() as sftp:
        async with sftp.open(path, "rb") as f:
            data = await f.read(limit)
        return data.decode("utf-8", errors="replace")


async def write_text(c: SSHClient, path: str, content: str, use_sudo: bool = False) -> None:
    if use_sudo:
        # запись в root-owned файл через sudo tee
        import base64
        b64 = base64.b64encode(content.encode()).decode()
        r = await c.sudo(f"echo {b64} | base64 -d > {path!r}")
        if not r.ok:
            raise PermissionError(r.stderr)
    else:
        async with c.conn.start_sftp_client() as sftp:
            async with sftp.open(path, "wb") as f:
                await f.write(content.encode())