from fastapi import APIRouter, Depends, HTTPException, Request
from sqlalchemy.orm import Session
from typing import Optional

from app.core.database import get_db
from app.core.security import get_current_user
from app.models.auth import User
from app.schemas.network import (
    NetworkCreate, NetworkUpdate, Network, NetworkListResponse,
    NetworkStats, IPAddressListResponse, IPAddressUpdate, IPAddress
)
from app.services.network_service import NetworkService
from app.services.audit_service import AuditService, AuditAction

router = APIRouter(
    prefix="/networks",
    tags=["网段管理"],
    dependencies=[Depends(get_current_user)],
)


def _client_info(request: Request) -> tuple[str, str]:
    return (
        request.client.host if request.client else "",
        (request.headers.get("user-agent") or "")[:500],
    )


@router.get("", response_model=NetworkListResponse, summary="获取网段列表")
def get_networks(
    skip: int = 0,
    limit: int = 100,
    group_name: Optional[str] = None,
    db: Session = Depends(get_db)
):
    """获取所有网段列表"""
    total, items = NetworkService.get_list(db, skip=skip, limit=limit, group_name=group_name)
    return {"total": total, "items": items}


@router.get("/stats", response_model=list[NetworkStats], summary="获取所有网段统计")
def get_all_network_stats(db: Session = Depends(get_db)):
    """获取所有网段的统计信息"""
    return NetworkService.get_all_stats(db)


@router.get("/{network_id}", response_model=Network, summary="获取网段详情")
def get_network(network_id: int, db: Session = Depends(get_db)):
    """根据ID获取网段详情"""
    network = NetworkService.get_by_id(db, network_id)
    if not network:
        raise HTTPException(status_code=404, detail="网段不存在")
    return network


@router.get("/{network_id}/stats", response_model=NetworkStats, summary="获取网段统计")
def get_network_stats(network_id: int, db: Session = Depends(get_db)):
    """获取指定网段的统计信息"""
    stats = NetworkService.get_stats(db, network_id)
    if not stats:
        raise HTTPException(status_code=404, detail="网段不存在")
    return stats


@router.get("/{network_id}/ips", response_model=IPAddressListResponse, summary="获取网段下的IP列表")
def get_network_ips(
    network_id: int,
    skip: int = 0,
    limit: int = 200,
    db: Session = Depends(get_db)
):
    """获取指定网段下的所有IP地址"""
    from app.services.ip_service import IPService
    total, items = IPService.get_list(db, network_id=network_id, skip=skip, limit=limit)
    return {"total": total, "items": items}


@router.post("", response_model=Network, status_code=201, summary="创建网段")
def create_network(
    network_in: NetworkCreate,
    request: Request,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """创建新网段，支持CIDR格式"""
    existing = NetworkService.get_by_cidr(db, network_in.cidr)
    if existing:
        raise HTTPException(status_code=400, detail="该网段已存在")

    ip, ua = _client_info(request)
    try:
        network = NetworkService.create(db, network_in)
    except ValueError as e:
        raise HTTPException(status_code=400, detail=str(e))

    AuditService.record(
        db,
        action=AuditAction.NETWORK_CREATE,
        user=current_user,
        resource_type="network",
        resource_id=network.id,
        resource_name=network.cidr,
        method="POST",
        path=str(request.url.path),
        ip_address=ip,
        user_agent=ua,
        detail={"cidr": network.cidr, "name": network.name},
    )
    return network


@router.put("/{network_id}", response_model=Network, summary="更新网段")
def update_network(
    network_id: int,
    network_in: NetworkUpdate,
    request: Request,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """更新网段信息"""
    old = NetworkService.get_by_id(db, network_id)
    if not old:
        raise HTTPException(status_code=404, detail="网段不存在")

    network = NetworkService.update(db, network_id, network_in)
    if not network:
        raise HTTPException(status_code=404, detail="网段不存在")

    ip, ua = _client_info(request)
    AuditService.record(
        db,
        action=AuditAction.NETWORK_UPDATE,
        user=current_user,
        resource_type="network",
        resource_id=network.id,
        resource_name=network.cidr,
        method="PUT",
        path=str(request.url.path),
        ip_address=ip,
        user_agent=ua,
        detail={
            "before": {"name": old.name, "gateway": old.gateway, "group_name": old.group_name, "vlan_id": old.vlan_id, "description": old.description},
            "after":  {"name": network.name, "gateway": network.gateway, "group_name": network.group_name, "vlan_id": network.vlan_id, "description": network.description},
        },
    )
    return network


@router.delete("/{network_id}", summary="删除网段")
def delete_network(
    network_id: int,
    request: Request,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """删除网段及其下的所有IP记录"""
    network = NetworkService.get_by_id(db, network_id)
    if not network:
        raise HTTPException(status_code=404, detail="网段不存在")
    cidr_snapshot = network.cidr

    success = NetworkService.delete(db, network_id)
    if not success:
        raise HTTPException(status_code=404, detail="网段不存在")

    ip, ua = _client_info(request)
    AuditService.record(
        db,
        action=AuditAction.NETWORK_DELETE,
        user=current_user,
        resource_type="network",
        resource_id=network_id,
        resource_name=cidr_snapshot,
        method="DELETE",
        path=str(request.url.path),
        ip_address=ip,
        user_agent=ua,
        detail={"cidr": cidr_snapshot},
    )
    return {"message": "删除成功"}