import json, os, sys, hmac, hashlib, base64, uuid, datetime
import urllib.request, urllib.error


def _cfg():
    return json.loads(os.environ.get("INTEGRATION_SECRETS", "{}"))


def _inputs():
    return json.loads(os.environ.get("INTEGRATION_INPUTS", "{}"))


def call(uri, cfg, data_payload=None):
    base_url = str(cfg.get("base_url", "")).rstrip("/")
    app_id = str(cfg.get("app_id", ""))
    app_key = str(cfg.get("app_key", ""))
    access_key = str(cfg.get("access_key", ""))
    secret_key = str(cfg.get("secret_key", ""))

    request_id = str(uuid.uuid4())
    hdr_date = datetime.datetime.utcnow().strftime("%a, %d %b %Y %H:%M:%S UTC")
    to_sign = hdr_date + ":" + request_id + ":" + uri + ":" + app_key
    sig = base64.b64encode(
        hmac.new(base64.b64decode(secret_key), to_sign.encode("utf-8"), hashlib.sha1).digest()
    ).decode("utf-8")

    headers = {
        "Authorization": "MC " + access_key + ":" + sig,
        "x-mc-app-id": app_id,
        "x-mc-date": hdr_date,
        "x-mc-req-id": request_id,
        "Content-Type": "application/json",
        "Accept": "application/json",
    }
    body = {"data": [data_payload] if data_payload is not None else []}
    req = urllib.request.Request(base_url + uri, data=json.dumps(body).encode("utf-8"), headers=headers, method="POST")
    with urllib.request.urlopen(req, timeout=60) as r:
        raw = r.read()
        resp = json.loads(raw) if raw else {}
    fails = resp.get("fail") if isinstance(resp, dict) else None
    if fails:
        # Mimecast returns errors in the 'fail' array even on HTTP 200
        raise Exception("Mimecast error: " + json.dumps(fails))
    return resp


def _run(fn):
    try:
        print(json.dumps(fn(_cfg(), _inputs())))
    except urllib.error.HTTPError as e:
        print(json.dumps({"error": "HTTP " + str(e.code), "detail": e.read().decode("utf-8", "replace")}))
        sys.exit(1)
    except Exception as e:
        print(json.dumps({"error": str(e)}))
        sys.exit(1)


def main(cfg, inputs):
    sender = inputs.get("sender")
    if not sender:
        raise Exception("sender is required")
    recipient = inputs.get("recipient")
    if not recipient:
        raise Exception("recipient is required")
    action = inputs.get("action")

    payload = {
        "sender": sender,
        "to": recipient,
        "action": action or "block",
    }
    return call("/api/managedsender/permit-or-block-sender", cfg, payload)


_run(main)