"""Service discovery."""
import json
import os
from typing import Dict, Tuple

from .constants import PROD_ENVIRONMENT, QA_ENVIRONMENT, UAT_ENVIRONMENT

SERVICE_URL_SPEC = "{protocol}://{environment}-{service_name}.{domain}"
SERVICE_DEFAULT_DOMAIN = "theorchard.io"


def get_owsclient_service_map() -> Dict[str, str]:
    """Get the service mapping from environment."""
    service_map = os.environ.get("OWSREQUEST_SERVICE_MAP")
    if service_map:
        try:
            mapping = json.loads(service_map)
        except (json.JSONDecodeError, TypeError):
            pass
        else:
            if isinstance(mapping, dict):
                return mapping
    return {}


owsclient_service_map = get_owsclient_service_map()


def discover_service_url(environment: str, service_name: str) -> Tuple[str, str]:
    """Discover the service url for a given service name and environment."""
    service_name = service_name.lower()
    environment = environment.lower()

    if environment in [QA_ENVIRONMENT, PROD_ENVIRONMENT]:
        url = SERVICE_URL_SPEC.format(
            environment=environment,
            service_name=service_name,
            domain=SERVICE_DEFAULT_DOMAIN,
            protocol="https",
        )
        return environment, url

    if environment == UAT_ENVIRONMENT:
        if service_name in owsclient_service_map:
            return environment, owsclient_service_map[service_name]
        return environment, SERVICE_URL_SPEC.format(
            environment=environment,
            service_name=service_name,
            domain=SERVICE_DEFAULT_DOMAIN,
            protocol="https",
        )

    if environment in ["test", "dev"] and service_name in owsclient_service_map:
        try:
            return environment, owsclient_service_map[service_name]
        except KeyError:
            pass

    # Default to qa
    url = SERVICE_URL_SPEC.format(
        environment=QA_ENVIRONMENT,
        service_name=service_name,
        domain=SERVICE_DEFAULT_DOMAIN,
        protocol="https",
    )
    return QA_ENVIRONMENT, url