import Joi = require("joi");
import { errors } from "../errors";
import { getGraphQlClient } from "../graphql/graphQlClient";
import { auth } from "../graphql/queries";
import { warnings } from "../warnings";

export class Auth {
    private static instance: Auth;

    private apiKey: string | undefined;
    private token: string | undefined;

    private constructor() {}

    private static getInstance(): Auth {
        if (!Auth.instance) {
            Auth.init();
        }
        return Auth.instance;
    }

    public static init(apiKey?: string): void {
        apiKey = Joi.attempt(apiKey, Joi.string().optional().label("apiKey"));

        if (!Auth.instance) {
            Auth.instance = new Auth();
        }

        const newApiKey = apiKey ?? process.env.DIGGITHY_API_KEY;

        if (!newApiKey) {
            console.warn(warnings.noApiKeyConfigured);
        }

        if (newApiKey !== Auth.instance.apiKey) {
            Auth.instance.apiKey = newApiKey;
            Auth.instance.token = undefined;
        }
    }

    public static getToken(): Promise<string> {
        const instance = Auth.getInstance();

        if (!instance.apiKey) {
            throw new Error(errors.noApiKeyConfigured);
        }

        if (instance.token) return Promise.resolve(instance.token);

        return getGraphQlClient()
            .query({
                query: auth,
                variables: {
                    apiKey: instance.apiKey,
                },
            })
            .then((result) => {
                if (result.error) throw new Error(result.error.message);
                if (!result.data?.auth?.token) {
                    throw new Error(errors.noTokenReturned);
                }

                instance.token = result.data.auth.token;
                return result.data.auth.token;
            });
    }
}