"""
Rules.py
    Contiene los endpoints de CRUD de reglas.
"""

import re

from fastapi import APIRouter, Depends, HTTPException, Request, status
from sqlalchemy.orm import Session
from database import get_db
import models
import schemas
from typing import List
from datetime import datetime
from auth import get_current_user
from audit import log_action
 
router = APIRouter()
 
@router.post("/rules/", response_model=schemas.RuleResponse, tags=['Rules'])
def create_rule(
    rule:         schemas.RuleCreate,
    request:      Request,
    db:           Session = Depends(get_db),
    current_user: int = Depends(get_current_user)
):
     # Validar que la regex compile antes de guardar
    try:
        re.compile(rule.regex)
    except re.error as e:
        raise HTTPException(
            status_code=status.HTTP_400_BAD_REQUEST,
            detail=f"Expresión regular inválida: {e}"
        )
    
    db_rule = models.Rule(**rule.model_dump(exclude={"apply_to_history"}))
    db.add(db_rule)
    db.flush()  # para tener db_rule.id antes del commit
 
    # Auditoría
    log_action(
        db=db, entity_type='rule', entity_id=db_rule.id,
        action='create', user_id=current_user,
        after=db_rule, ip_address=request.client.host
    )
 
    
    if rule.apply_to_history:
        # Traer mensajes en batches para no cargar todo en memoria
        batch_size = 500
        offset = 0
        while True:
            messages = db.query(models.Message).offset(offset).limit(batch_size).all()
            if not messages:
                break
            for message in messages:
                try:
                    if re.search(rule.regex, message.content, re.IGNORECASE):
                        new_alert = models.Alert(
                            message_id=message.id_mess_g,
                            group_id=message.group_id,
                            rule_id=db_rule.id,
                            status="open",
                            notes=f"Detected pattern: {rule.regex}",
                            created_at=datetime.utcnow()
                        )
                        db.add(new_alert)
                except re.error:
                    break
            offset += batch_size

    db.commit()
    db.refresh(db_rule)
    return db_rule

@router.get("/rules/", response_model=List[schemas.RuleResponse], tags=['Rules'])
def read_rules(
    skip:         int = 0,
    limit:        int = 100,
    db:           Session = Depends(get_db),
    current_user: int = Depends(get_current_user)
):
    return db.query(models.Rule).offset(skip).limit(limit).all()
 
@router.get("/rules/search/", response_model=List[schemas.RuleResponse], tags=['Rules'])
def search_rules(
    q:            str,
    skip:         int = 0,
    limit:        int = 100,
    db:           Session = Depends(get_db),
    current_user: int = Depends(get_current_user)
):
    return db.query(models.Rule).filter(
        models.Rule.description.ilike(f"%{q}%")
    ).offset(skip).limit(limit).all()
 
@router.get("/rules/{rule_id}", response_model=schemas.RuleResponse, tags=['Rules'])
def read_rule(
    rule_id:      int,
    db:           Session = Depends(get_db),
    current_user: int = Depends(get_current_user)
):
    db_rule = db.query(models.Rule).filter(models.Rule.id == rule_id).first()
    if not db_rule:
        raise HTTPException(status_code=404, detail="Rule not found")
    return db_rule
 
@router.put("/rules/{rule_id}", response_model=schemas.RuleResponse, tags=['Rules'])
def update_rule(
    rule_id:      int,
    rule:         schemas.RuleCreate,
    request:      Request,
    db:           Session = Depends(get_db),
    current_user: int = Depends(get_current_user)
):
    db_rule = db.query(models.Rule).filter(models.Rule.id == rule_id).first()
    if not db_rule:
        raise HTTPException(status_code=404, detail="Rule not found")
 
    # Capturar estado anterior antes de modificar
    before_snapshot = {
        'id': db_rule.id,
        'description': db_rule.description,
        'regex': db_rule.regex,
        'severity': db_rule.severity,
        'is_active': db_rule.is_active,
    }
 
    for field, value in rule.model_dump().items():
        setattr(db_rule, field, value)
 
    log_action(
        db=db, entity_type='rule', entity_id=rule_id,
        action='update', user_id=current_user,
        before=before_snapshot, after=db_rule,
        ip_address=request.client.host
    )
 
    db.commit()
    db.refresh(db_rule)
    return db_rule
 
@router.delete("/rules/{rule_id}", tags=['Rules'])
def delete_rule(
    rule_id:      int,
    request:      Request,
    db:           Session = Depends(get_db),
    current_user: int = Depends(get_current_user)
):
    db_rule = db.query(models.Rule).filter(models.Rule.id == rule_id).first()
    if not db_rule:
        raise HTTPException(status_code=404, detail="Rule not found")
 
    log_action(
        db=db, entity_type='rule', entity_id=rule_id,
        action='delete', user_id=current_user,
        before=db_rule, ip_address=request.client.host
    )
 
    db.delete(db_rule)
    db.commit()
    return {"message": "Rule deleted successfully"}