from fastapi import APIRouter, Depends, Query
from pydantic import BaseModel
from sqlalchemy import func, select
from sqlalchemy.orm import Session

from app import schemas as s
from app.api.v1.prefixes import _prefix_outs
from app.db import get_db
from app.models import Address, AddressStatus, AuditLog, Prefix, PrefixStatus, Vrf
from app.security import current_user
from app.services import capacity, utilization

router = APIRouter(dependencies=[Depends(current_user)])


class Overview(BaseModel):
    prefixes: int
    vrfs: int
    assigned: int
    capacity: int
    utilization: int
    reserved: int
    top_prefixes: list[s.PrefixOut]
    recent_changes: list[s.AuditOut]


@router.get("/overview", response_model=Overview, tags=["overview"])
def overview(db: Session = Depends(get_db)):
    prefixes = db.scalars(select(Prefix).where(Prefix.status == PrefixStatus.active)).all()
    outs = _prefix_outs(db, list(prefixes))
    parents = {p.parent_id for p in outs if p.parent_id}
    leaves = [p for p in outs if p.id not in parents]  # ёмкость считаем по листьям, чтобы не удваивать
    leaves4 = [p for p in leaves if p.family == 4]  # IPv6-пространство несопоставимо по размеру — в метрики использования не входит
    cap = sum(p.capacity for p in leaves4)
    v4 = func.family(Address.address) == 4
    assigned = db.scalar(select(func.count()).select_from(Address).where(Address.status == AddressStatus.assigned, v4)) or 0
    reserved = db.scalar(select(func.count()).select_from(Address).where(Address.status == AddressStatus.reserved, v4)) or 0
    top = sorted((p for p in leaves4 if p.capacity > 1), key=lambda p: p.utilization, reverse=True)[:4]
    recent = db.scalars(select(AuditLog).order_by(AuditLog.id.desc()).limit(4)).all()
    return Overview(
        prefixes=db.scalar(select(func.count()).select_from(Prefix)) or 0,
        vrfs=db.scalar(select(func.count()).select_from(Vrf)) or 0,
        assigned=assigned, capacity=cap, utilization=utilization(assigned, cap), reserved=reserved,
        top_prefixes=top, recent_changes=[s.AuditOut.from_row(r) for r in recent],
    )