"""备份与恢复服务。"""
import logging
import os
import shutil
import sqlite3
from datetime import datetime, timezone

from models import Backup
from database import db

log = logging.getLogger("socks.backup")

_BACKUP_DIR = None


def set_backup_dir(path):
    global _BACKUP_DIR
    _BACKUP_DIR = os.path.abspath(path)
    os.makedirs(_BACKUP_DIR, exist_ok=True)


def get_backup_dir():
    return _BACKUP_DIR or os.path.join(os.path.dirname(__file__), "..", "backups")


def create_backup(note=""):
    """创建数据库备份。"""
    global _BACKUP_DIR
    if not _BACKUP_DIR:
        _BACKUP_DIR = get_backup_dir()
    os.makedirs(_BACKUP_DIR, exist_ok=True)

    ts = datetime.now().strftime("%Y%m%d_%H%M%S")
    filename = f"sm_backup_{ts}.db"
    dest = os.path.join(_BACKUP_DIR, filename)

    db_uri = db.engine.url.render_as_string(hide_password=False)
    if db_uri.startswith("sqlite:///"):
        src = db_uri.replace("sqlite:///", "", 1)
        if not src.startswith("/"):
            src = os.path.join(os.path.dirname(__file__), "..", src)
        shutil.copy2(src, dest)
    else:
        # 其他数据库类型需要不同处理
        log.warning("不支持的数据库类型备份: %s", db_uri)
        return {"error": "不支持的数据库类型"}

    size = os.path.getsize(dest)
    with db.app.app_context():
        b = Backup(filename=filename, path=dest, size=size, note=note)
        db.session.add(b)
        db.session.commit()

    log.info("备份完成: %s (%.1f MB)", filename, size / 1024 / 1024)
    return {"filename": filename, "path": dest, "size": size}


def list_backups():
    """列出所有备份。"""
    with db.app.app_context():
        backups = db.session.query(Backup).order_by(Backup.created_at.desc()).all()
        return [{
            "id": b.id,
            "filename": b.filename,
            "path": b.path,
            "size_mb": round(b.size / 1024 / 1024, 1),
            "created_at": b.created_at.isoformat(),
            "note": b.note,
            "exists": os.path.exists(b.path),
        } for b in backups]


def restore_backup(backup_id):
    """从备份恢复。"""
    with db.app.app_context():
        b = db.session.query(Backup).get(backup_id)
        if not b or not os.path.exists(b.path):
            return {"error": "备份文件不存在"}

        db_uri = db.engine.url.render_as_string(hide_password=False)
        if not db_uri.startswith("sqlite:///"):
            return {"error": "不支持的数据库类型"}

        src = b.path
        dest = db_uri.replace("sqlite:///", "", 1)
        if not dest.startswith("/"):
            dest = os.path.join(os.path.dirname(__file__), "..", dest)

        # 先备份当前数据库
        if os.path.exists(dest):
            backup_current = f"{dest}.pre_restore_{datetime.now().strftime('%Y%m%d_%H%M%S')}"
            shutil.copy2(dest, backup_current)

        shutil.copy2(src, dest)
        log.info("从备份恢复: %s -> %s", b.filename, dest)
        return {"ok": True, "restored_from": b.filename}


def cleanup_old_backups(keep=10):
    """清理旧备份，保留最近 N 份。"""
    with db.app.app_context():
        backups = db.session.query(Backup).order_by(Backup.created_at.desc()).all()
        for b in backups[keep:]:
            if os.path.exists(b.path):
                os.remove(b.path)
            db.session.delete(b)
            log.info("删除旧备份: %s", b.filename)
        db.session.commit()