from __future__ import annotations

from datetime import datetime
from pathlib import Path
import shutil

from flask import current_app


class BackupService:
    def create_backup(self):
        target = Path(current_app.config['BACKUP_PATH']) / f'backup_{datetime.utcnow().strftime("%Y%m%d_%H%M%S")}'
        target.mkdir(parents=True, exist_ok=True)
        base_dir = Path(current_app.root_path).parent
        for part in ['instance', 'storage/archive', 'storage/pdf']:
            src = base_dir / part
            if src.exists():
                shutil.copytree(src, target / Path(part).name, dirs_exist_ok=True)
        archive = shutil.make_archive(str(target), 'zip', root_dir=target)
        return archive

    def get_database_backup_meta(self) -> dict:
        uri = current_app.config.get('SQLALCHEMY_DATABASE_URI', '')
        backup_dir = Path(current_app.config['BACKUP_PATH'])
        engine = 'unknown'
        if '://' in uri:
            engine = uri.split('://', 1)[0]
        sqlite_supported = uri.startswith('sqlite:///') and not uri.endswith(':memory:')
        sqlite_path = None
        sqlite_exists = False
        if sqlite_supported:
            sqlite_path = Path(uri.replace('sqlite:///', '', 1))
            sqlite_exists = sqlite_path.exists()
        return {
            'engine': engine,
            'backup_dir': str(backup_dir),
            'sqlite_supported': sqlite_supported,
            'sqlite_path': str(sqlite_path) if sqlite_path else None,
            'sqlite_exists': sqlite_exists,
            'notes': [
                'Kopia z panelu działa plikowo dla SQLite.',
                'Dla PostgreSQL, MySQL i innych silników wymagany jest natywny dump bazy poza aplikacją.',
            ],
        }

    def create_database_backup(self) -> str:
        target_dir = Path(current_app.config['BACKUP_PATH'])
        target_dir.mkdir(parents=True, exist_ok=True)
        timestamp = datetime.utcnow().strftime('%Y%m%d_%H%M%S')
        uri = current_app.config.get('SQLALCHEMY_DATABASE_URI', '')
        if uri.startswith('sqlite:///') and not uri.endswith(':memory:'):
            source = Path(uri.replace('sqlite:///', '', 1))
            if not source.exists():
                raise FileNotFoundError(f'Plik bazy nie istnieje: {source}')
            target = target_dir / f'db_backup_{timestamp}.sqlite3'
            shutil.copy2(source, target)
            return str(target)
        target = target_dir / f'db_backup_{timestamp}.txt'
        target.write_text(
            """Automatyczna kopia DB dla bieżącego silnika nie jest obsługiwana plikowo.
W panelu admina kopia działa bezpośrednio tylko dla SQLite.
Wykonaj backup natywnym narzędziem bazy danych.
""",
            encoding='utf-8',
        )
        return str(target)