from __future__ import annotations

import re
from collections.abc import Callable
from dataclasses import dataclass
from pathlib import Path
from typing import Literal
from uuid import uuid4

from app.pipeline.config import join_path
from app.pipeline.file_manager import (
    check_input_dir_access,
    connect_samba,
    ensure_dir_exists,
)


@dataclass(frozen=True)
class SMBDiagnosticStep:
    stage: str
    status: Literal["ok", "error", "skipped"]
    details: str


@dataclass(frozen=True)
class SMBDiagnosticResult:
    test_path: str
    steps: tuple[SMBDiagnosticStep, ...]


def build_user_params(samba_user: str, samba_password: str) -> dict[str, str]:
    return {
        "user_name": samba_user,
        "password": samba_password,
    }


def check_access_and_list_files(
    smb_base_path: str,
    input_dir: str,
    samba_user: str,
    samba_password: str,
) -> tuple[bool, str, list[str]]:
    if not samba_user:
        return False, "Введите логин SAMBA.", []

    user_params = build_user_params(samba_user, samba_password)
    try:
        samba_conn = connect_samba(smb_base_path=smb_base_path, user_params=user_params)
    except RuntimeError as exc:
        return False, _format_connect_error(str(exc)), []

    # Early handshake to surface auth/network errors clearly.
    try:
        with samba_conn:
            pass
    except Exception as exc:  # noqa: BLE001
        return False, _format_connect_error(str(exc)), []

    try:
        ensure_dir_exists(input_dir, samba_conn=samba_conn)
    except Exception as exc:  # noqa: BLE001
        return False, f"Не удалось создать входную папку: {input_dir}. {exc}", []
    if not samba_conn.path_exists(input_dir):
        return (
            False,
            (
                "Не удалось создать входную папку: "
                f"{input_dir}. Проверьте права на родительский каталог."
            ),
            [],
        )

    ok, error = check_input_dir_access(Path(input_dir), samba_conn=samba_conn)
    if not ok:
        return False, error or "Ошибка доступа к входной папке.", []

    try:
        with samba_conn:
            entries = sorted(samba_conn.listdir(input_dir))
            files: list[str] = []
            for name in entries:
                full_path = input_dir.rstrip("/\\") + "\\" + name
                if samba_conn.is_file(full_path):
                    files.append(name)
    except Exception as exc:  # noqa: BLE001
        return False, f"Ошибка чтения содержимого входной папки: {input_dir}. {exc}", []

    return True, "", files


def diagnose_smb_access(
    smb_base_path: str,
    parent_dir: str,
    samba_user: str,
    samba_password: str,
) -> SMBDiagnosticResult:
    test_path = join_path(parent_dir, f"Input_diag_{uuid4().hex[:8]}")
    steps: list[SMBDiagnosticStep] = []

    if not samba_user:
        steps.append(
            SMBDiagnosticStep(
                stage="Подключение к SMB",
                status="error",
                details="Введите логин SAMBA.",
            )
        )
        return SMBDiagnosticResult(test_path=test_path, steps=tuple(steps))

    try:
        samba_conn = connect_samba(
            smb_base_path=smb_base_path,
            user_params=build_user_params(samba_user, samba_password),
        )
        with samba_conn:
            pass
    except Exception as exc:  # noqa: BLE001
        steps.append(_diagnostic_error("Подключение к SMB", exc))
        return SMBDiagnosticResult(test_path=test_path, steps=tuple(steps))

    steps.append(_diagnostic_ok("Подключение к SMB"))
    _run_diagnostic_step(
        steps,
        "Проверка родительской папки",
        lambda: samba_conn.stat(parent_dir),
    )
    _run_diagnostic_step(
        steps,
        "Чтение родительской папки",
        lambda: samba_conn.listdir(parent_dir),
    )

    try:
        created = _run_diagnostic_step(
            steps,
            "Создание тестовой папки",
            lambda: samba_conn.mkdir(test_path),
        )
        if created:
            _run_diagnostic_step(
                steps,
                "Проверка созданной папки",
                lambda: samba_conn.stat(test_path),
            )
            _run_diagnostic_step(
                steps,
                "Чтение созданной папки",
                lambda: samba_conn.listdir(test_path),
            )
            _run_diagnostic_step(
                steps,
                "Проверка папки в родительском каталоге",
                lambda: _require_directory_in_parent(
                    samba_conn.listdir(parent_dir),
                    test_path,
                ),
            )
        else:
            for stage in (
                "Проверка созданной папки",
                "Чтение созданной папки",
                "Проверка папки в родительском каталоге",
            ):
                steps.append(
                    SMBDiagnosticStep(
                        stage=stage,
                        status="skipped",
                        details="Пропущено: создание тестовой папки завершилось ошибкой.",
                    )
                )
    finally:
        _run_diagnostic_step(
            steps,
            "Удаление тестовой папки",
            lambda: samba_conn.rmdir(test_path),
        )

    return SMBDiagnosticResult(test_path=test_path, steps=tuple(steps))


def _run_diagnostic_step(
    steps: list[SMBDiagnosticStep],
    stage: str,
    action: Callable[[], object],
) -> bool:
    try:
        action()
    except Exception as exc:  # noqa: BLE001
        steps.append(_diagnostic_error(stage, exc))
        return False
    steps.append(_diagnostic_ok(stage))
    return True


def _require_directory_in_parent(entries: list[str], test_path: str) -> None:
    directory_name = test_path.rstrip("/\\").rsplit("\\", 1)[-1]
    if directory_name not in entries:
        raise FileNotFoundError(
            f"Созданная папка {directory_name} отсутствует в списке родителя."
        )


def _diagnostic_ok(stage: str) -> SMBDiagnosticStep:
    return SMBDiagnosticStep(stage=stage, status="ok", details="Успешно.")


def _diagnostic_error(stage: str, exc: Exception) -> SMBDiagnosticStep:
    details = str(exc)
    status = getattr(exc, "ntstatus", None) or getattr(exc, "status", None)
    if status is None:
        match = re.search(r"\bSTATUS_[A-Z0-9_]+\b", details, flags=re.IGNORECASE)
        status = match.group(0).upper() if match else None
    suffix = f"; NTSTATUS: {status}" if status is not None else ""
    return SMBDiagnosticStep(
        stage=stage,
        status="error",
        details=f"{type(exc).__name__}: {details}{suffix}",
    )


def _format_connect_error(details: str) -> str:
    normalized = details.lower()
    auth_hints = (
        "status_logon_failure",
        "logon failure",
        "authentication",
        "no username or password",
    )
    if any(hint in normalized for hint in auth_hints):
        return f"Ошибка аутентификации SMB. {details}"
    return f"Ошибка подключения к SMB. {details}"