import time
import jwt
import aiohttp
import asyncio
import configparser

from flask import Flask, request, jsonify
from flask_sqlalchemy import SQLAlchemy


config = configparser.ConfigParser()
config.read("config.ini")

REGISTER_AUTH = config.get("AUTH", "REGISTER_AUTH", fallback=None)
MANAGE_AUTH = config.get("AUTH", "MANAGE_AUTH", fallback=None)

SQLALCHEMY_DATABASE_URI = config.get(
    "DATABASE",
    "SQLALCHEMY_DATABASE_URI",
    fallback="sqlite:///device_tokens.db"
)

auth_key_path = config.get(
    "APNS",
    "auth_key_path",
    fallback="./APNSAuthKey.p8"
)

auth_key_id = config.get("APNS", "auth_key_id", fallback=None)
team_id = config.get("APNS", "team_id", fallback=None)
topic = config.get("APNS", "topic", fallback=None)

APNS_URL = "https://api.push.apple.com"

if not all([
    REGISTER_AUTH,
    MANAGE_AUTH,
    auth_key_id,
    team_id,
    topic
]):
    raise ValueError("Fehlende Pflichtfelder in der Konfiguration!")


app = Flask(__name__)

app.config["SQLALCHEMY_DATABASE_URI"] = SQLALCHEMY_DATABASE_URI
app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False

db = SQLAlchemy(app)

class DeviceToken(db.Model):
    id = db.Column(db.Integer, primary_key=True)

    device_token = db.Column(
        db.String(256),
        nullable=False,
        unique=True
    )

def authenticate(req, required_token):
    auth_header = req.headers.get("Authorization")
    return auth_header == f"Bearer {required_token}"

with open(auth_key_path, "r") as f:
    APNS_PRIVATE_KEY = f.read()


def generate_apns_token():
    return jwt.encode(
        {
            "iss": team_id,
            "iat": int(time.time())
        },
        APNS_PRIVATE_KEY,
        algorithm="ES256",
        headers={
            "alg": "ES256",
            "kid": auth_key_id
        }
    )


async def send_notification(
    session,
    device_token,
    title,
    body
):
    try:

        jwt_token = generate_apns_token()

        payload = {
            "aps": {
                "alert": {
                    "title": title,
                    "body": body
                },
                "sound": "default",
                "badge": 1
            }
        }

        headers = {
            "authorization": f"bearer {jwt_token}",
            "apns-topic": topic,
            "apns-push-type": "alert",
            "content-type": "application/json"
        }

        url = f"{APNS_URL}/3/device/{device_token}"

        async with session.post(
            url,
            json=payload,
            headers=headers
        ) as response:

            if response.status != 200:

                error_text = await response.text()

                print(
                    f"APNS Fehler {response.status} "
                    f"für {device_token}: {error_text}"
                )

    except Exception as e:
        print(f"Fehler beim Senden: {e}")

@app.route("/api/registerDeviceToken", methods=["POST"])
def register_device_token():

    if not authenticate(request, REGISTER_AUTH):
        return jsonify({
            "error": "Unauthorized"
        }), 401

    try:

        data = request.get_json()

        if not data or "device_token" not in data:
            return jsonify({
                "error": "device_token fehlt"
            }), 400

        device_token = data["device_token"]

        existing = DeviceToken.query.filter_by(
            device_token=device_token
        ).first()

        if existing:
            return jsonify({
                "message": "Bereits registriert"
            }), 200

        db.session.add(
            DeviceToken(device_token=device_token)
        )

        db.session.commit()

        return jsonify({
            "message": "Device Token registriert"
        }), 200

    except Exception as e:

        db.session.rollback()

        return jsonify({
            "error": "Interner Serverfehler",
            "details": str(e)
        }), 500


@app.route("/api/notify", methods=["POST"])
def notify():

    if not authenticate(request, MANAGE_AUTH):
        return jsonify({
            "error": "Unauthorized"
        }), 401

    try:

        data = request.get_json()

        severity = data.get("severity")
        notification_text = data.get("notification")

        if not severity or not notification_text:
            return jsonify({
                "error": (
                    "severity und notification "
                    "sind erforderlich"
                )
            }), 400

        severity_icons = {
            "info": "",
            "warning": "⚠️ ",
            "urgent": "❗️ ",
            "danger": "❌ "
        }

        if severity not in severity_icons:
            return jsonify({
                "error": "Ungültige severity"
            }), 400

        title = (
            f"{severity_icons[severity]}"
            f"{notification_text}"
        )

        async def send_all():

            async with aiohttp.ClientSession() as session:

                tasks = []

                for token in DeviceToken.query.all():

                    tasks.append(
                        send_notification(
                            session=session,
                            device_token=token.device_token,
                            title=title,
                            body=notification_text
                        )
                    )

                await asyncio.gather(*tasks)

        asyncio.run(send_all())

        return jsonify({
            "message": "Benachrichtigungen gesendet"
        }), 200

    except Exception as e:

        return jsonify({
            "error": "Interner Serverfehler",
            "details": str(e)
        }), 500


@app.route("/showdevicetokens", methods=["GET"])
def show_device_tokens():

    tokens = DeviceToken.query.all()

    return jsonify({
        "device_tokens": [
            token.device_token
            for token in tokens
        ]
    })


@app.route(
    "/api/deleteAllDeviceTokens",
    methods=["POST"]
)
def delete_all_device_tokens():

    if not authenticate(request, MANAGE_AUTH):
        return jsonify({
            "error": "Unauthorized"
        }), 401

    try:

        db.session.query(DeviceToken).delete()

        db.session.commit()

        return jsonify({
            "message": "Alle Device Tokens gelöscht"
        }), 200

    except Exception as e:

        db.session.rollback()

        return jsonify({
            "error": "Interner Serverfehler",
            "details": str(e)
        }), 500


if __name__ == "__main__":

    with app.app_context():
        db.create_all()

    app.run(
        host="0.0.0.0",
        port=3000
    )