import json
from datetime import datetime, timedelta
from flask import Blueprint, render_template, request, jsonify, redirect, url_for, abort, session, flash
from flask_login import current_user, login_required
from functools import wraps
from sqlalchemy import desc
from sqlalchemy.orm import joinedload

from models import GuestRequest, Job, Printer, User, UserPermission, Notification, get_cached_session
from utils.logging_config import get_logger

guest_blueprint = Blueprint('guest', __name__)
logger = get_logger("guest")

# Hilfsfunktionen
def can_approve_jobs(user_id):
    """Prüft, ob ein Benutzer Anfragen genehmigen darf."""
    with get_cached_session() as db_session:
        permission = db_session.query(UserPermission).filter_by(user_id=user_id).first()
        if not permission:
            return False
        return permission.can_approve_jobs

def approver_required(f):
    """Decorator zur Prüfung der Genehmigungsberechtigung."""
    @wraps(f)
    @login_required
    def decorated_function(*args, **kwargs):
        if not can_approve_jobs(current_user.id):
            abort(403, "Keine Berechtigung zum Genehmigen von Anfragen")
        return f(*args, **kwargs)
    return decorated_function

# Gast-Routen
@guest_blueprint.route('/request', methods=['GET'])
def guest_request_form():
    """Formular für Gastanfragen anzeigen."""
    with get_cached_session() as db_session:
        printers = db_session.query(Printer).filter_by(active=True).all()
        # Drucker-Liste von der Session trennen für Template-Verwendung
        db_session.expunge_all()
    return render_template('guest_request.html', printers=printers)

@guest_blueprint.route('/requests/overview', methods=['GET'])
def guest_requests_overview():
    """Öffentliche Übersicht aller Druckanträge mit zensierten persönlichen Daten."""
    try:
        with get_cached_session() as db_session:
            # Alle Gastanfragen mit eager loading des printer-Relationships laden
            guest_requests = db_session.query(GuestRequest).options(
                joinedload(GuestRequest.printer)
            ).order_by(desc(GuestRequest.created_at)).all()
            
            # Daten für Gäste aufbereiten (persönliche Daten zensieren)
            public_requests = []
            for req in guest_requests:
                # Name zensieren: Nur ersten Buchstaben und letzten Buchstaben anzeigen
                censored_name = "***"
                if req.name and len(req.name) > 0:
                    if len(req.name) == 1:
                        censored_name = req.name[0] + "***"
                    elif len(req.name) == 2:
                        censored_name = req.name[0] + "***" + req.name[-1]
                    else:
                        censored_name = req.name[0] + "***" + req.name[-1]
                
                # E-Mail zensieren
                censored_email = "***@***.***"
                if req.email and "@" in req.email:
                    email_parts = req.email.split("@")
                    if len(email_parts[0]) > 2:
                        censored_email = email_parts[0][:2] + "***@" + email_parts[1]
                    else:
                        censored_email = "***@" + email_parts[1]
                
                # Grund zensieren (nur erste 20 Zeichen anzeigen)
                censored_reason = "***"
                if req.reason:
                    if len(req.reason) > 20:
                        censored_reason = req.reason[:20] + "***"
                    else:
                        censored_reason = req.reason[:10] + "***" if len(req.reason) > 10 else "***"
                
                # Drucker-Info laden (jetzt durch eager loading verfügbar)
                printer_name = "Unbekannt"
                if req.printer:
                    printer_name = req.printer.name
                
                # Job-Status laden, falls vorhanden
                job_status = None
                if req.job_id:
                    job = db_session.query(Job).filter_by(id=req.job_id).first()
                    if job:
                        job_status = job.status
                
                public_requests.append({
                    "id": req.id,
                    "name": censored_name,
                    "email": censored_email,
                    "reason": censored_reason,
                    "duration_min": req.duration_min,
                    "created_at": req.created_at,
                    "status": req.status,
                    "printer_name": printer_name,
                    "job_status": job_status
                })
                
        logger.info(f"Öffentliche Druckanträge-Übersicht aufgerufen - {len(public_requests)} Einträge")
        
        return render_template('guest_requests_overview.html', requests=public_requests)
        
    except Exception as e:
        logger.error(f"Fehler beim Laden der öffentlichen Druckanträge-Übersicht: {str(e)}")
        return render_template('guest_requests_overview.html', requests=[], error="Fehler beim Laden der Daten")

@guest_blueprint.route('/request/<int:request_id>', methods=['GET'])
def guest_request_status(request_id):
    """Status einer Gastanfrage anzeigen."""
    with get_cached_session() as db_session:
        # Guest Request mit eager loading des printer-Relationships laden
        guest_request = db_session.query(GuestRequest).options(
            joinedload(GuestRequest.printer)
        ).filter_by(id=request_id).first()
        
        if not guest_request:
            abort(404, "Anfrage nicht gefunden")
        
        # Nur wenn Status "approved" ist, OTP generieren und anzeigen
        otp_code = None
        if guest_request.status == "approved" and not guest_request.otp_code:
            otp_code = guest_request.generate_otp()
            db_session.commit()
        
        # Zugehörigen Job laden, falls vorhanden
        job = None
        if guest_request.job_id:
            job = db_session.query(Job).filter_by(id=guest_request.job_id).first()
            
        # Objekte explizit von der Session trennen, um sie außerhalb verwenden zu können
        db_session.expunge(guest_request)
        if job:
            db_session.expunge(job)
    
    return render_template('guest_status.html', 
                          request=guest_request, 
                          job=job,
                          otp_code=otp_code)

# API-Endpunkte
@guest_blueprint.route('/api/guest/requests', methods=['POST'])
def api_create_guest_request():
    """Neue Gastanfrage erstellen."""
    data = request.get_json()
    if not data:
        return jsonify({"error": "Keine Daten erhalten"}), 400
    
    # Pflichtfelder prüfen
    name = data.get('name')
    if not name:
        return jsonify({"error": "Name ist erforderlich"}), 400
    
    # Optionale Felder
    email = data.get('email')
    reason = data.get('reason')
    duration_min = data.get('duration_min', 60)  # Standard: 1 Stunde
    printer_id = data.get('printer_id')
    
    # IP-Adresse erfassen
    author_ip = request.remote_addr
    
    try:
        with get_cached_session() as db_session:
            # Drucker prüfen
            if printer_id:
                printer = db_session.query(Printer).filter_by(id=printer_id, active=True).first()
                if not printer:
                    return jsonify({"error": "Ungültiger Drucker ausgewählt"}), 400
            
            # Neue Anfrage erstellen
            guest_request = GuestRequest(
                name=name,
                email=email,
                reason=reason,
                duration_min=duration_min,
                printer_id=printer_id,
                author_ip=author_ip
            )
            
            db_session.add(guest_request)
            db_session.commit()
            
            # Benachrichtigung für Genehmiger erstellen
            Notification.create_for_approvers(
                notification_type="guest_request",
                payload={
                    "request_id": guest_request.id,
                    "name": guest_request.name,
                    "created_at": guest_request.created_at.isoformat(),
                    "status": guest_request.status
                }
            )
            
            logger.info(f"Neue Gastanfrage erstellt: ID {guest_request.id}, Name: {name}")
            
            return jsonify({
                "success": True,
                "request_id": guest_request.id,
                "status": guest_request.status,
                "redirect_url": url_for('guest.guest_request_status', request_id=guest_request.id)
            })
            
    except Exception as e:
        logger.error(f"Fehler beim Erstellen der Gastanfrage: {str(e)}")
        return jsonify({"error": "Fehler beim Verarbeiten der Anfrage"}), 500

@guest_blueprint.route('/api/guest/requests/<int:request_id>', methods=['GET'])
def api_get_guest_request(request_id):
    """Status einer Gastanfrage abrufen."""
    try:
        with get_cached_session() as db_session:
            guest_request = db_session.query(GuestRequest).filter_by(id=request_id).first()
            if not guest_request:
                return jsonify({"error": "Anfrage nicht gefunden"}), 404
            
            # OTP wird nie über die API zurückgegeben
            response_data = guest_request.to_dict()
            response_data.pop("otp_code", None)
            
            return jsonify(response_data)
            
    except Exception as e:
        logger.error(f"Fehler beim Abrufen der Gastanfrage: {str(e)}")
        return jsonify({"error": "Fehler beim Verarbeiten der Anfrage"}), 500

@guest_blueprint.route('/api/requests/<int:request_id>/approve', methods=['POST'])
@approver_required
def api_approve_request(request_id):
    """Gastanfrage genehmigen."""
    try:
        data = request.get_json() or {}
        approval_notes = data.get('notes', '')
        printer_id = data.get('printer_id')  # Optional: Drucker zuweisen/ändern
        
        with get_cached_session() as db_session:
            guest_request = db_session.query(GuestRequest).filter_by(id=request_id).first()
            if not guest_request:
                return jsonify({"error": "Anfrage nicht gefunden"}), 404
            
            if guest_request.status != "pending":
                return jsonify({"error": "Anfrage wurde bereits bearbeitet"}), 400
            
            # Drucker validieren, falls angegeben
            if printer_id:
                printer = db_session.query(Printer).filter_by(id=printer_id, active=True).first()
                if not printer:
                    return jsonify({"error": "Ungültiger Drucker ausgewählt"}), 400
                guest_request.printer_id = printer_id
            
            # Sicherstellen, dass ein Drucker zugewiesen ist
            if not guest_request.printer_id:
                return jsonify({"error": "Kein Drucker zugewiesen. Bitte wählen Sie einen Drucker aus."}), 400
            
            # Anfrage genehmigen
            guest_request.status = "approved"
            guest_request.processed_by = current_user.id
            guest_request.processed_at = datetime.now()
            guest_request.approval_notes = approval_notes
            
            # OTP generieren
            otp_plain = guest_request.generate_otp()
            
            # Zugehörigen Job erstellen
            start_time = datetime.now() + timedelta(minutes=5)  # Start in 5 Minuten
            end_time = start_time + timedelta(minutes=guest_request.duration_min)
            
            # Admin-Benutzer als Eigentümer verwenden
            admin_user = db_session.query(User).filter_by(role="admin").first()
            
            job = Job(
                name=f"Gastauftrag: {guest_request.name}",
                description=guest_request.reason or "Gastauftrag",
                user_id=admin_user.id,
                printer_id=guest_request.printer_id,
                start_at=start_time,
                end_at=end_time,
                status="scheduled",
                duration_minutes=guest_request.duration_min,
                owner_id=admin_user.id
            )
            
            db_session.add(job)
            db_session.flush()  # ID generieren
            
            # Job-ID in Gastanfrage speichern
            guest_request.job_id = job.id
            
            db_session.commit()
            
            logger.info(f"Gastanfrage {request_id} genehmigt von Admin {current_user.id} ({current_user.name})")
            
            return jsonify({
                "success": True,
                "status": "approved",
                "job_id": job.id,
                "otp": otp_plain,  # Nur in dieser Antwort wird der OTP-Klartext zurückgegeben
                "approved_by": current_user.name,
                "approved_at": guest_request.processed_at.isoformat(),
                "notes": approval_notes
            })
            
    except Exception as e:
        logger.error(f"Fehler beim Genehmigen der Gastanfrage: {str(e)}")
        return jsonify({"error": "Fehler beim Verarbeiten der Anfrage"}), 500

@guest_blueprint.route('/api/requests/<int:request_id>/deny', methods=['POST'])
@approver_required
def api_deny_request(request_id):
    """Gastanfrage ablehnen."""
    try:
        data = request.get_json() or {}
        rejection_reason = data.get('reason', '')
        
        if not rejection_reason.strip():
            return jsonify({"error": "Ablehnungsgrund ist erforderlich"}), 400
        
        with get_cached_session() as db_session:
            guest_request = db_session.query(GuestRequest).filter_by(id=request_id).first()
            if not guest_request:
                return jsonify({"error": "Anfrage nicht gefunden"}), 404
            
            if guest_request.status != "pending":
                return jsonify({"error": "Anfrage wurde bereits bearbeitet"}), 400
            
            # Anfrage ablehnen
            guest_request.status = "denied"
            guest_request.processed_by = current_user.id
            guest_request.processed_at = datetime.now()
            guest_request.rejection_reason = rejection_reason
            
            db_session.commit()
            
            logger.info(f"Gastanfrage {request_id} abgelehnt von Admin {current_user.id} ({current_user.name}): {rejection_reason}")
            
            return jsonify({
                "success": True,
                "status": "denied",
                "rejected_by": current_user.name,
                "rejected_at": guest_request.processed_at.isoformat(),
                "reason": rejection_reason
            })
            
    except Exception as e:
        logger.error(f"Fehler beim Ablehnen der Gastanfrage: {str(e)}")
        return jsonify({"error": "Fehler beim Verarbeiten der Anfrage"}), 500

@guest_blueprint.route('/api/jobs/start/<string:otp>', methods=['POST'])
def api_start_job_with_otp(otp):
    """Job mit OTP starten."""
    try:
        with get_cached_session() as db_session:
            # Alle genehmigten Anfragen mit OTP durchsuchen
            guest_requests = db_session.query(GuestRequest).filter_by(status="approved").all()
            
            valid_request = None
            for req in guest_requests:
                if req.verify_otp(otp):
                    valid_request = req
                    break
            
            if not valid_request:
                return jsonify({"error": "Ungültiger oder abgelaufener Code"}), 400
            
            if not valid_request.job_id:
                return jsonify({"error": "Kein Job mit diesem Code verknüpft"}), 400
            
            # Job laden
            job = db_session.query(Job).filter_by(id=valid_request.job_id).first()
            if not job:
                return jsonify({"error": "Job nicht gefunden"}), 404
            
            # Job-Status prüfen
            if job.status != "scheduled":
                return jsonify({"error": "Job kann nicht gestartet werden"}), 400
            
            # Grace-Period prüfen (5 Minuten vor bis 5 Minuten nach geplantem Start)
            now = datetime.now()
            start_time = job.start_at
            grace_start = start_time - timedelta(minutes=5)
            grace_end = start_time + timedelta(minutes=5)
            
            if now < grace_start:
                return jsonify({
                    "error": f"Der Job kann erst ab {grace_start.strftime('%H:%M')} Uhr gestartet werden"
                }), 400
            
            if now > job.end_at:
                return jsonify({"error": "Der Job ist bereits abgelaufen"}), 400
            
            # Job starten
            job.status = "active"
            job.start_at = now  # Aktualisiere Startzeit auf jetzt
            
            # OTP als verwendet markieren
            valid_request.otp_used_at = now
            
            db_session.commit()
            
            logger.info(f"Job {job.id} mit OTP {otp} gestartet von IP: {request.remote_addr}")
            
            return jsonify({
                "success": True,
                "job_id": job.id,
                "status": job.status,
                "started_at": job.start_at.isoformat(),
                "end_at": job.end_at.isoformat()
            })
            
    except Exception as e:
        logger.error(f"Fehler beim Starten des Jobs mit OTP: {str(e)}")
        return jsonify({"error": "Fehler beim Verarbeiten der Anfrage"}), 500

@guest_blueprint.route('/api/notifications', methods=['GET'])
@login_required
def api_get_notifications():
    """Benachrichtigungen für den aktuellen Benutzer abrufen."""
    try:
        # Zeitstempel für Filter (nur neue Benachrichtigungen)
        since = request.args.get('since')
        if since:
            try:
                since_date = datetime.fromisoformat(since)
            except ValueError:
                return jsonify({"error": "Ungültiges Datumsformat"}), 400
        else:
            since_date = None
        
        with get_cached_session() as db_session:
            query = db_session.query(Notification).filter_by(
                user_id=current_user.id,
                read=False
            )
            
            if since_date:
                query = query.filter(Notification.created_at > since_date)
            
            notifications = query.order_by(desc(Notification.created_at)).all()
            
            return jsonify({
                "count": len(notifications),
                "notifications": [n.to_dict() for n in notifications]
            })
            
    except Exception as e:
        logger.error(f"Fehler beim Abrufen der Benachrichtigungen: {str(e)}")
        return jsonify({"error": "Fehler beim Verarbeiten der Anfrage"}), 500

@guest_blueprint.route('/api/notifications/<int:notification_id>/read', methods=['POST'])
@login_required
def api_mark_notification_read(notification_id):
    """Benachrichtigung als gelesen markieren."""
    try:
        with get_cached_session() as db_session:
            notification = db_session.query(Notification).filter_by(
                id=notification_id,
                user_id=current_user.id
            ).first()
            
            if not notification:
                return jsonify({"error": "Benachrichtigung nicht gefunden"}), 404
            
            notification.read = True
            db_session.commit()
            
            return jsonify({"success": True})
            
    except Exception as e:
        logger.error(f"Fehler beim Markieren der Benachrichtigung als gelesen: {str(e)}")
        return jsonify({"error": "Fehler beim Verarbeiten der Anfrage"}), 500

@guest_blueprint.route('/api/admin/requests', methods=['GET'])
@approver_required
def api_get_all_requests():
    """Alle Gastanfragen für Admins abrufen."""
    try:
        # Filter-Parameter
        status_filter = request.args.get('status', 'all')  # all, pending, approved, denied
        limit = int(request.args.get('limit', 50))
        offset = int(request.args.get('offset', 0))
        
        with get_cached_session() as db_session:
            # Query mit eager loading
            query = db_session.query(GuestRequest).options(
                joinedload(GuestRequest.printer),
                joinedload(GuestRequest.job),
                joinedload(GuestRequest.processed_by_user)
            )
            
            # Status-Filter anwenden
            if status_filter != 'all':
                query = query.filter(GuestRequest.status == status_filter)
            
            # Sortierung: Pending zuerst, dann nach Erstellungsdatum
            query = query.order_by(
                desc(GuestRequest.status == 'pending'),
                desc(GuestRequest.created_at)
            )
            
            # Pagination
            total_count = query.count()
            requests = query.offset(offset).limit(limit).all()
            
            # Daten für Admin aufbereiten
            admin_requests = []
            for req in requests:
                request_data = req.to_dict()
                
                # Zusätzliche Admin-Informationen
                request_data.update({
                    "can_be_processed": req.status == "pending",
                    "is_overdue": (
                        req.status == "approved" and 
                        req.job and 
                        req.job.end_at < datetime.now()
                    ) if req.job else False,
                    "time_since_creation": (datetime.now() - req.created_at).total_seconds() / 3600 if req.created_at else 0  # Stunden
                })
                
                admin_requests.append(request_data)
            
            return jsonify({
                "success": True,
                "requests": admin_requests,
                "pagination": {
                    "total": total_count,
                    "limit": limit,
                    "offset": offset,
                    "has_more": (offset + limit) < total_count
                },
                "stats": {
                    "total": total_count,
                    "pending": db_session.query(GuestRequest).filter_by(status='pending').count(),
                    "approved": db_session.query(GuestRequest).filter_by(status='approved').count(),
                    "denied": db_session.query(GuestRequest).filter_by(status='denied').count()
                }
            })
            
    except Exception as e:
        logger.error(f"Fehler beim Abrufen der Admin-Gastanfragen: {str(e)}")
        return jsonify({"error": "Fehler beim Verarbeiten der Anfrage"}), 500

@guest_blueprint.route('/api/admin/requests/<int:request_id>', methods=['GET'])
@approver_required
def api_get_request_details(request_id):
    """Detaillierte Informationen zu einer Gastanfrage für Admins abrufen."""
    try:
        with get_cached_session() as db_session:
            guest_request = db_session.query(GuestRequest).options(
                joinedload(GuestRequest.printer),
                joinedload(GuestRequest.job),
                joinedload(GuestRequest.processed_by_user)
            ).filter_by(id=request_id).first()
            
            if not guest_request:
                return jsonify({"error": "Anfrage nicht gefunden"}), 404
            
            # Vollständige Admin-Informationen
            request_data = guest_request.to_dict()
            
            # Verfügbare Drucker für Zuweisung
            available_printers = db_session.query(Printer).filter_by(active=True).all()
            request_data["available_printers"] = [p.to_dict() for p in available_printers]
            
            # Job-Historie falls vorhanden
            if guest_request.job:
                job_data = guest_request.job.to_dict()
                job_data["is_active"] = guest_request.job.status in ["scheduled", "running"]
                job_data["is_overdue"] = guest_request.job.end_at < datetime.now() if guest_request.job.end_at else False
                request_data["job_details"] = job_data
            
            return jsonify({
                "success": True,
                "request": request_data
            })
            
    except Exception as e:
        logger.error(f"Fehler beim Abrufen der Gastanfrage-Details: {str(e)}")
        return jsonify({"error": "Fehler beim Verarbeiten der Anfrage"}), 500

@guest_blueprint.route('/api/admin/requests/<int:request_id>/update', methods=['PUT'])
@approver_required
def api_update_request(request_id):
    """Gastanfrage aktualisieren (nur für Admins)."""
    try:
        data = request.get_json()
        if not data:
            return jsonify({"error": "Keine Daten erhalten"}), 400
        
        with get_cached_session() as db_session:
            guest_request = db_session.query(GuestRequest).filter_by(id=request_id).first()
            if not guest_request:
                return jsonify({"error": "Anfrage nicht gefunden"}), 404
            
            # Erlaubte Felder für Updates
            allowed_fields = ['printer_id', 'duration_min', 'approval_notes', 'rejection_reason']
            changes_made = False
            
            for field in allowed_fields:
                if field in data:
                    if field == 'printer_id' and data[field]:
                        # Drucker validieren
                        printer = db_session.query(Printer).filter_by(id=data[field], active=True).first()
                        if not printer:
                            return jsonify({"error": "Ungültiger Drucker ausgewählt"}), 400
                    
                    setattr(guest_request, field, data[field])
                    changes_made = True
            
            if changes_made:
                guest_request.processed_by = current_user.id
                guest_request.processed_at = datetime.now()
                db_session.commit()
                
                logger.info(f"Gastanfrage {request_id} aktualisiert von Admin {current_user.id}")
                
                return jsonify({
                    "success": True,
                    "message": "Anfrage erfolgreich aktualisiert",
                    "updated_by": current_user.name,
                    "updated_at": guest_request.processed_at.isoformat()
                })
            else:
                return jsonify({"error": "Keine Änderungen vorgenommen"}), 400
            
    except Exception as e:
        logger.error(f"Fehler beim Aktualisieren der Gastanfrage: {str(e)}")
        return jsonify({"error": "Fehler beim Verarbeiten der Anfrage"}), 500

# Admin-Routen
@guest_blueprint.route('/admin/requests', methods=['GET'])
@approver_required
def admin_requests_management():
    """Admin-Oberfläche für die Verwaltung von Gastanfragen."""
    return render_template('admin_guest_requests.html')