import base64
import json
import os
import subprocess
import urllib.request

import functions_framework
from google.cloud import secretmanager


def get_webhook_url(project_id: str) -> str | None:
    try:
        client = secretmanager.SecretManagerServiceClient()
        name = f"projects/{project_id}/secrets/webhook-url/versions/latest"
        response = client.access_secret_version(request={"name": name})
        return response.payload.data.decode("UTF-8")
    except Exception:
        return None


def send_webhook(url: str, message: str) -> None:
    payload = json.dumps({"text": message}).encode()
    req = urllib.request.Request(
        url,
        data=payload,
        headers={"Content-Type": "application/json"},
        method="POST",
    )
    with urllib.request.urlopen(req, timeout=10):
        pass


@functions_framework.cloud_event
def billing_alert(cloud_event):
    project_id = os.environ.get("PROJECT_ID", "")
    service = os.environ.get("CLOUD_RUN_SERVICE", "")
    region = os.environ.get("REGION", "")

    # Dekod Pub/Sub-melding
    data = base64.b64decode(cloud_event.data["message"]["data"]).decode()
    alert = json.loads(data)

    budget_amount = alert.get("budgetAmount", "?")
    cost_amount = alert.get("costAmount", "?")
    alert_threshold = alert.get("alertThresholdExceeded", 0)

    print(f"Billing alert: {cost_amount} / {budget_amount} ({alert_threshold*100:.0f}%)")

    webhook_url = get_webhook_url(project_id)
    base_msg = (
        f"🚨 *OSVauco Cost Alert*
"
        f"Prosjekt: `{project_id}`
"
        f"Forbruk: `{cost_amount}` av budsjett `{budget_amount}`
"
        f"Terskel: `{alert_threshold*100:.0f}%`"
    )

    # Kjør auto-teardown kun ved 100% terskel
    if alert_threshold >= 1.0:
        print("100% terskel nådd — starter auto-teardown")
        try:
            subprocess.run(
                [
                    "gcloud", "run", "services", "delete", service,
                    f"--region={region}",
                    f"--project={project_id}",
                    "--quiet",
                ],
                check=True,
                capture_output=True,
            )
            teardown_msg = base_msg + "

ℹ️ Auto-teardown utført: Cloud Run stoppet."
        except subprocess.CalledProcessError as e:
            teardown_msg = base_msg + f"

⚠️ Auto-teardown FEILET: {e.stderr.decode()}"
        msg = teardown_msg
    else:
        msg = base_msg + "

⚠️ Ingen tiltak nå — men pass på forbruket."

    if webhook_url:
        try:
            send_webhook(webhook_url, msg)
            print("Webhook-alert sendt")
        except Exception as ex:
            print(f"Webhook feilet: {ex}")
    else:
        print("Ingen webhook-url i Secret Manager — hopper over varsling")