from __future__ import annotations

from typing import Any

import httpx
from flask import current_app, has_app_context

from .client import ServiceClient
from .config import ServiceConfig
from .errors import ServiceConfigError


def init_service_clients(app) -> None:
    configs = app.config.get("SERVICES", {})
    clients: dict[str, ServiceClient] = {}
    for name, value in configs.items():
        if "base_url" not in value:
            raise ServiceConfigError(f"service {name} missing base_url")
        clients[name] = ServiceClient(ServiceConfig.from_mapping(name, value))
    app.extensions["iti_service_clients"] = clients


def register_service_client(
    app,
    name: str,
    config: dict[str, Any],
    *,
    transport: httpx.BaseTransport | None = None,
) -> ServiceClient:
    client = ServiceClient(ServiceConfig.from_mapping(name, config), transport=transport)
    clients = app.extensions.setdefault("iti_service_clients", {})
    clients[name] = client
    return client


def service_client(name: str) -> ServiceClient:
    if not has_app_context():
        raise ServiceConfigError("service_client() requires an app context")
    clients = current_app.extensions.get("iti_service_clients", {})
    client = clients.get(name)
    if client is None:
        raise ServiceConfigError(f"service client not configured: {name}")
    return client