import os
import queue
import stat
import subprocess
import threading
from itertools import product as itproduct
from os.path import expanduser
from pathlib import Path
from subprocess import DEVNULL, STDOUT

import paramiko
from tqdm import tqdm

known_hosts = Path(expanduser("~/.ssh/known_hosts"))
hostname = "ilona.isti.cnr.it"
username = "volpi"

__exec_main = "cd tesi; /home/volpi/.local/bin/poetry run main"
__exec_log = "/usr/bin/tail -f -n 0 tesi/quacc.log"
__log_file = "remote.log"
__target_dir = Path("/home/volpi/tesi")
__to_sync_up = {
    "dir": [
        "quacc",
        "baselines",
        "qcpanel",
    ],
    "file": [
        "conf.yaml",
        "run.py",
        "remote.py",
        "merge_data.py",
        "pyproject.toml",
    ],
}
__to_sync_down = {
    "dir": [
        "output",
    ],
    "file": [],
}


def prune_remote(sftp: paramiko.SFTPClient, remote: Path):
    _ex_list = []
    mode = sftp.stat(str(remote)).st_mode
    if stat.S_ISDIR(mode):
        for f in sftp.listdir(str(remote)):
            _ex_list.append([prune_remote, sftp, remote / f])
        _ex_list.append([sftp.rmdir, str(remote)])
    elif stat.S_ISREG(mode):
        _ex_list.append([sftp.remove, str(remote)])

    return _ex_list


def put_dir(sftp: paramiko.SFTPClient, from_: Path, to_: Path):
    _ex_list = []

    _ex_list.append([sftp.mkdir, str(to_)])

    from_list = os.listdir(from_)
    for f in from_list:
        if (from_ / f).is_file():
            _ex_list.append([sftp.put, str(from_ / f), str(to_ / f)])
        elif (from_ / f).is_dir():
            _ex_list += put_dir(sftp, from_ / f, to_ / f)

    try:
        to_list = sftp.listdir(str(to_))
        for f in to_list:
            if f not in from_list:
                _ex_list += prune_remote(sftp, to_ / f)
    except FileNotFoundError:
        pass

    return _ex_list


def get_dir(sftp: paramiko.SFTPClient, from_: Path, to_: Path):
    _ex_list = []

    if not (to_.exists() and to_.is_dir()):
        _ex_list.append([os.mkdir, to_])

    for f in sftp.listdir(str(from_)):
        mode = sftp.stat(str(from_ / f)).st_mode
        if stat.S_ISDIR(mode):
            _ex_list += get_dir(sftp, from_ / f, to_ / f)
            # _ex_list.append([sftp.rmdir, str(from_ / f)])
        elif stat.S_ISREG(mode):
            _ex_list.append([sftp.get, str(from_ / f), str(to_ / f)])
            # _ex_list.append([sftp.remove, str(from_ / f)])

    return _ex_list


def sync_code(*, ssh: paramiko.SSHClient = None, verbose=False):
    _was_ssh = ssh is not None
    if ssh is None:
        ssh = paramiko.SSHClient()
        ssh.load_host_keys(known_hosts)
        ssh.connect(hostname=hostname, username=username)

    sftp = ssh.open_sftp()

    to_move = [item for k, vs in __to_sync_up.items() for item in itproduct([k], vs)]
    _ex_list = []
    for mode, f in to_move:
        from_ = Path(f).absolute()
        to_ = __target_dir / f
        if mode == "dir":
            _ex_list += put_dir(sftp, from_, to_)
        elif mode == "file":
            _ex_list.append([sftp.put, str(from_), str(to_)])

    for _ex in tqdm(_ex_list, desc="synching code: "):
        fn_ = _ex[0]
        try:
            fn_(*_ex[1:])
        except IOError:
            if verbose:
                print(f"Info: directory {to_} already exists.")

    sftp.close()
    if not _was_ssh:
        ssh.close()


def sync_output(*, ssh: paramiko.SSHClient = None):
    _was_ssh = ssh is not None
    if ssh is None:
        ssh = paramiko.SSHClient()
        ssh.load_host_keys(known_hosts)
        ssh.connect(hostname=hostname, username=username)

    sftp = ssh.open_sftp()

    to_move = [item for k, vs in __to_sync_down.items() for item in itproduct([k], vs)]
    _ex_list = []
    for mode, f in to_move:
        from_ = __target_dir / f
        to_ = Path(f).absolute()
        if mode == "dir":
            _ex_list += get_dir(sftp, from_, to_)
        elif mode == "file":
            _ex_list.append([sftp.get, str(from_), str(to_)])

    for _ex in tqdm(_ex_list, desc="synching output: "):
        fn_ = _ex[0]
        fn_(*_ex[1:])

    sftp.close()
    if not _was_ssh:
        ssh.close()


def _echo_channel(ch: paramiko.ChannelFile):
    while line := ch.readline():
        print(line, end="")


def _echo_log(ssh: paramiko.SSHClient, q_: queue.Queue):
    _, rout, _ = ssh.exec_command(__exec_log, timeout=5.0)
    while True:
        try:
            _line = rout.readline()
            with open(__log_file, "a") as f:
                f.write(_line)
        except TimeoutError:
            pass

        try:
            q_.get_nowait()
            return
        except queue.Empty:
            pass


def remote(detatch=False):
    ssh = paramiko.SSHClient()
    ssh.load_host_keys(known_hosts)
    ssh.connect(hostname=hostname, username=username)
    sync_code(ssh=ssh)

    __to_exec = __exec_main
    if detatch:
        __to_exec += " &> out & disown"

    _, rout, rerr = ssh.exec_command(__to_exec)

    if detatch:
        ssh.close()
        return

    q = queue.Queue()
    _tlog = threading.Thread(target=_echo_log, args=[ssh, q])
    _tlog.start()

    _tchans = [threading.Thread(target=_echo_channel, args=[ch]) for ch in [rout, rerr]]

    for th in _tchans:
        th.start()

    for th in _tchans:
        th.join()

    q.put(None)

    sync_output(ssh=ssh)
    _tlog.join()

    ssh.close()