from __future__ import annotations

import json
import logging
import shutil
from datetime import datetime
from pathlib import Path

from app.config import Config
from app.services.host import host_path, run_on_host

logger = logging.getLogger(__name__)

BACKUP_TARGETS = {
    "resolved.conf": "etc/systemd/resolved.conf",
    "resolved.conf.d": "etc/systemd/resolved.conf.d",
    "sources.list": "etc/apt/sources.list",
    "sources.list.d": "etc/apt/sources.list.d",
    "daemon.json": "etc/docker/daemon.json",
    "gitconfig_system": "etc/gitconfig",
}


def _backup_dir(name: str) -> Path:
    path = Config.BACKUP_DIR / name
    path.mkdir(parents=True, exist_ok=True)
    return path


def _copy_if_exists(src: Path, dst: Path) -> None:
    if not src.exists():
        return
    if src.is_dir():
        if dst.exists():
            shutil.rmtree(dst)
        shutil.copytree(src, dst)
    else:
        dst.parent.mkdir(parents=True, exist_ok=True)
        shutil.copy2(src, dst)


def _restore_file(relative: str, backup_root: Path) -> None:
    key = relative.replace("/", "_").replace(".", "_")
    for name, rel in BACKUP_TARGETS.items():
        if rel == relative or rel.endswith(relative):
            key = name
            break

    src = backup_root / key
    dst = host_path(relative)
    if not src.exists():
        if dst.exists() and key in ("daemon.json", "gitconfig_system"):
            dst.unlink(missing_ok=True)
        return

    if src.is_dir():
        if dst.exists():
            shutil.rmtree(dst)
        shutil.copytree(src, dst)
    else:
        dst.parent.mkdir(parents=True, exist_ok=True)
        shutil.copy2(src, dst)


def create_backup(label: str = "manual") -> Path:
    timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
    backup_root = _backup_dir(f"{timestamp}_{label}")
    manifest: dict = {"label": label, "timestamp": timestamp, "files": {}}

    for key, relative in BACKUP_TARGETS.items():
        src = host_path(relative)
        dst = backup_root / key
        _copy_if_exists(src, dst)
        manifest["files"][key] = {
            "relative": relative,
            "existed": src.exists(),
        }

    gitconfig_global = host_path("root/.gitconfig")
    if not gitconfig_global.exists():
        gitconfig_global = Path.home() / ".gitconfig"
    if gitconfig_global.exists():
        shutil.copy2(gitconfig_global, backup_root / "gitconfig_global")
        manifest["files"]["gitconfig_global"] = {"path": str(gitconfig_global), "existed": True}

    pip_conf = host_path("etc/pip.conf")
    if pip_conf.exists():
        shutil.copy2(pip_conf, backup_root / "pip.conf")
        manifest["files"]["pip.conf"] = {"relative": "etc/pip.conf", "existed": True}

    npmrc = host_path("root/.npmrc")
    if npmrc.exists():
        shutil.copy2(npmrc, backup_root / "npmrc")
        manifest["files"]["npmrc"] = {"relative": "root/.npmrc", "existed": True}

    mirror_dropin = host_path("etc/systemd/resolved.conf.d/mirror-manager.conf")
    if mirror_dropin.exists():
        shutil.copy2(mirror_dropin, backup_root / "mirror_manager_resolved.conf")

    with open(backup_root / "manifest.json", "w", encoding="utf-8") as f:
        json.dump(manifest, f, ensure_ascii=False, indent=2)

    logger.info("Backup created at %s", backup_root)
    return backup_root


def restore_backup(backup_root: Path | str) -> dict:
    backup_root = Path(backup_root)
    if not backup_root.exists():
        return {"success": False, "error": "مسیر backup یافت نشد"}

    results: list[str] = []

    for key, relative in BACKUP_TARGETS.items():
        src = backup_root / key
        if src.exists():
            dst = host_path(relative)
            _copy_if_exists(src, dst)
            results.append(f"بازگردانی {relative}")

    gitconfig_backup = backup_root / "gitconfig_global"
    if gitconfig_backup.exists():
        for target in [host_path("root/.gitconfig"), host_path("home/.gitconfig")]:
            target.parent.mkdir(parents=True, exist_ok=True)
            shutil.copy2(gitconfig_backup, target)
        results.append("بازگردانی gitconfig global")

    pip_backup = backup_root / "pip.conf"
    if pip_backup.exists():
        dst = host_path("etc/pip.conf")
        dst.parent.mkdir(parents=True, exist_ok=True)
        shutil.copy2(pip_backup, dst)
        results.append("بازگردانی pip.conf")

    npmrc_backup = backup_root / "npmrc"
    if npmrc_backup.exists():
        dst = host_path("root/.npmrc")
        dst.parent.mkdir(parents=True, exist_ok=True)
        shutil.copy2(npmrc_backup, dst)
        results.append("بازگردانی .npmrc")

    dropin = host_path("etc/systemd/resolved.conf.d/mirror-manager.conf")
    mirror_backup = backup_root / "mirror_manager_resolved.conf"
    if mirror_backup.exists():
        dropin.parent.mkdir(parents=True, exist_ok=True)
        shutil.copy2(mirror_backup, dropin)
    elif dropin.exists():
        dropin.unlink()

    run_on_host(["systemctl", "restart", "systemd-resolved"])
    run_on_host(["systemctl", "restart", "docker"])

    return {"success": True, "restored": results}


def create_initial_backup() -> Path:
    return create_backup("initial")


def list_backups() -> list[dict]:
    backups = []
    if not Config.BACKUP_DIR.exists():
        return backups
    for path in sorted(Config.BACKUP_DIR.iterdir(), reverse=True):
        if path.is_dir():
            manifest_path = path / "manifest.json"
            label = path.name
            if manifest_path.exists():
                with open(manifest_path, encoding="utf-8") as f:
                    manifest = json.load(f)
                    label = manifest.get("label", path.name)
            backups.append({"path": str(path), "name": path.name, "label": label})
    return backups