"""Calendar upstream helpers — HTTP to EMAIL_URL/CALENDAR_URL.

Write paths (create / reschedule / cancel) follow the documented OpenAPI contract
but were not exercised live when this package was written; treat a non-2xx as an
upstream-contract finding before changing the request shape.
"""

from __future__ import annotations

import os
from urllib.parse import quote

import httpx
from dotenv import load_dotenv

load_dotenv()

CALENDAR_URL=os.getenv("CALENDAR_URL") or os.getenv("EMAIL_URL")
CALENDAR_API_TOKEN=os.getenv("CALENDAR_API_TOKEN") or os.getenv("EMAIL_API_TOKEN")


def _base_url():
    if not CALENDAR_URL:
        raise RuntimeError("CALENDAR_URL or EMAIL_URL must be set")
    return CALENDAR_URL.rstrip("/")


def _auth_headers(token=None):
    auth_token=token or CALENDAR_API_TOKEN
    if not auth_token:
        raise RuntimeError("CALENDAR_API_TOKEN or EMAIL_API_TOKEN must be set")
    return {"Authorization":f"Bearer {auth_token}"}


async def get_event(event_id, token=None):
    """GET {base}/calendar/events/{id} -> event dict, or None on 404."""
    encoded_id=quote(str(event_id),safe="")
    async with httpx.AsyncClient(timeout=30.0) as client:
        response=await client.get(
            f"{_base_url()}/calendar/events/{encoded_id}",
            headers={**_auth_headers(token),"accept":"application/json"},
        )
    if response.status_code==404:
        return None
    if response.status_code>=400:
        raise httpx.HTTPStatusError(
            response.text,
            request=response.request,
            response=response,
        )
    if not response.content:
        return {}
    return response.json()


async def create_event(payload, token=None):
    """POST {base}/calendar/events -> created event dict."""
    async with httpx.AsyncClient(timeout=30.0) as client:
        response=await client.post(
            f"{_base_url()}/calendar/events",
            json=payload,
            headers=_auth_headers(token),
        )
    if response.status_code>=400:
        raise httpx.HTTPStatusError(
            response.text,
            request=response.request,
            response=response,
        )
    if not response.content:
        return {}
    return response.json()


async def reschedule_event(event_id, payload, token=None):
    """PATCH {base}/calendar/events/{id}/reschedule -> updated event dict."""
    encoded_id=quote(str(event_id),safe="")
    async with httpx.AsyncClient(timeout=30.0) as client:
        response=await client.patch(
            f"{_base_url()}/calendar/events/{encoded_id}/reschedule",
            json=payload,
            headers=_auth_headers(token),
        )
    if response.status_code>=400:
        raise httpx.HTTPStatusError(
            response.text,
            request=response.request,
            response=response,
        )
    if not response.content:
        return {}
    return response.json()


async def cancel_event(event_id, comment=None, token=None):
    """POST {base}/calendar/events/{id}/cancel -> response body or empty dict."""
    encoded_id=quote(str(event_id),safe="")
    body={"comment":comment} if comment is not None else {}
    async with httpx.AsyncClient(timeout=30.0) as client:
        response=await client.post(
            f"{_base_url()}/calendar/events/{encoded_id}/cancel",
            json=body,
            headers=_auth_headers(token),
        )
    if response.status_code>=400:
        raise httpx.HTTPStatusError(
            response.text,
            request=response.request,
            response=response,
        )
    if not response.content:
        return {}
    return response.json()