"""SMTP2GO SMS REST API."""

import logging
import re

import requests
from django.conf import settings

from messaging.services import render_merge_tags

logger = logging.getLogger(__name__)


def _format_destination(phone: str) -> str:
    """Normalize stored phone to E.164-ish string SMTP2GO accepts."""
    digits = re.sub(r"\D", "", phone or "")
    if not digits:
        raise ValueError("Contact has no phone number")
    if phone.strip().startswith("+") and digits:
        return f"+{digits}"
    # US 10-digit local numbers → +1…
    if len(digits) == 10:
        return f"+1{digits}"
    if len(digits) == 11 and digits.startswith("1"):
        return f"+{digits}"
    return f"+{digits}"


def _provider_error_detail(response: requests.Response) -> str:
    """Prefer SMTP2GO JSON error text over bare HTTP reason."""
    try:
        data = response.json()
    except ValueError:
        text = (response.text or "").strip()
        return text[:500] if text else response.reason
    nested = data.get("data") if isinstance(data.get("data"), dict) else {}
    err = nested.get("error") or data.get("error") or ""
    code = nested.get("error_code") or data.get("error_code") or ""
    if err and code:
        return f"{err} ({code})"
    return str(err or code or response.reason)


def send_sms(message) -> str:
    contact = message.contact
    if not contact.phone:
        raise ValueError("Contact has no phone number")

    api_key = settings.SMTP2GO_SMS_API_KEY
    if not api_key:
        raise RuntimeError("SMTP2GO_SMS_API_KEY is not configured")

    campaign = message.campaign
    body = message.body_snapshot or campaign.body_override or (
        campaign.template.body if campaign.template else ""
    )
    body = render_merge_tags(body, contact)
    destination = _format_destination(contact.phone)

    # Current SMTP2GO /v3/sms/send schema: destination[] + content.
    payload = {
        "api_key": api_key,
        "destination": [destination],
        "content": body[:1600],
    }
    response = requests.post(
        settings.SMTP2GO_SMS_API_URL,
        json=payload,
        timeout=30,
    )
    if not response.ok:
        detail = _provider_error_detail(response)
        raise requests.HTTPError(
            f"{response.status_code} Client Error: {detail} for url: {response.url}",
            response=response,
        )

    data = response.json() if response.content else {}
    nested = data.get("data") if isinstance(data.get("data"), dict) else {}
    messages = nested.get("messages") if isinstance(nested.get("messages"), list) else []
    first = messages[0] if messages and isinstance(messages[0], dict) else {}
    return str(
        first.get("message_id")
        or nested.get("sms_id")
        or nested.get("message_id")
        or data.get("sms_id")
        or data.get("message_id")
        or data.get("request_id")
        or f"sms-{message.pk}"
    )