import ipaddress
import re
from typing import Optional, List

from fastapi import APIRouter, Depends, HTTPException
from pydantic import BaseModel, field_validator
from sqlalchemy import nullsfirst
from sqlalchemy.orm import Session

from database import get_db
import models

router = APIRouter()

_COLOR_RE = re.compile(r"^#[0-9a-fA-F]{6}$")


class VlanCreate(BaseModel):
    vlan_id: Optional[int] = None
    name: str
    cidr: Optional[str] = ""
    color: str = "#4A90D9"

    @field_validator("vlan_id")
    @classmethod
    def _vlan_id(cls, v: Optional[int]) -> Optional[int]:
        if v is not None and not (1 <= v <= 4094):
            raise ValueError("vlan_id must be between 1 and 4094")
        return v

    @field_validator("name")
    @classmethod
    def _name(cls, v: str) -> str:
        v = v.strip()
        if not v:
            raise ValueError("name cannot be empty")
        if len(v) > 100:
            raise ValueError("name too long (max 100 characters)")
        return v

    @field_validator("cidr")
    @classmethod
    def _cidr(cls, v: Optional[str]) -> Optional[str]:
        if v:
            try:
                ipaddress.ip_network(v, strict=False)
            except ValueError:
                raise ValueError(f"Invalid CIDR notation: {v!r}")
        return v

    @field_validator("color")
    @classmethod
    def _color(cls, v: str) -> str:
        if not _COLOR_RE.match(v):
            raise ValueError("color must be a 6-digit hex color (e.g. #4A90D9)")
        return v


class VlanOut(VlanCreate):
    id: int

    model_config = {"from_attributes": True}


@router.get("/", response_model=List[VlanOut])
def list_vlans(db: Session = Depends(get_db)):
    return db.query(models.Vlan).order_by(nullsfirst(models.Vlan.vlan_id)).all()


@router.post("/", response_model=VlanOut)
def create_vlan(vlan: VlanCreate, db: Session = Depends(get_db)):
    if vlan.vlan_id is not None:
        existing = db.query(models.Vlan).filter(models.Vlan.vlan_id == vlan.vlan_id).first()
        if existing:
            raise HTTPException(status_code=400, detail=f"VLAN {vlan.vlan_id} existe déjà")
    db_vlan = models.Vlan(**vlan.model_dump())
    db.add(db_vlan)
    db.commit()
    db.refresh(db_vlan)
    return db_vlan


@router.put("/{vlan_pk}", response_model=VlanOut)
def update_vlan(vlan_pk: int, vlan: VlanCreate, db: Session = Depends(get_db)):
    db_vlan = db.query(models.Vlan).filter(models.Vlan.id == vlan_pk).first()
    if not db_vlan:
        raise HTTPException(status_code=404, detail="VLAN introuvable")
    for k, v in vlan.model_dump().items():
        setattr(db_vlan, k, v)
    db.commit()
    db.refresh(db_vlan)
    return db_vlan


@router.delete("/{vlan_pk}")
def delete_vlan(vlan_pk: int, db: Session = Depends(get_db)):
    db_vlan = db.query(models.Vlan).filter(models.Vlan.id == vlan_pk).first()
    if not db_vlan:
        raise HTTPException(status_code=404, detail="VLAN introuvable")
    db.delete(db_vlan)
    db.commit()
    return {"ok": True}