const backendUri = `${window.location.protocol}//${window.location.hostname}:${window.location.port}`;
const getChallengeEndpoint = (provider: string) =>
    `${backendUri}/external-auth/challenge?provider=${provider}`;
let _currentOauthResultsHandler: (event: any) => void;
type OAuthResult = OAuthSuccessResult & OAuthErrorResult;
type OAuthResultEvent = {
    data: {
        type: string;
    } & OAuthResult;
};
type OAuthSuccessResult = {
    provider: string;
    code?: string;
}
type OAuthErrorResult = {
    provider: string;
    error?: string;
    errorDescription?: string;
}

export function getOAuthCode(provider: string): Promise<OAuthResult> {
    function createOAuthMessageHandler(
        resolve: (result: OAuthSuccessResult) => void,
        reject: (result: OAuthErrorResult) => void
    ) {
        const handler = (event: OAuthResultEvent) => {
            if (event.data && event.data.type === 'oauth-result') {
                const data = event.data;
                if (data.code) {
                    resolve({
                        provider: data.provider,
                        code: data.code,
                    });
                } else {
                    reject({
                        provider: data.provider,
                        error: data.error,
                        errorDescription: data.errorDescription,
                    });
                }
                window.removeEventListener('message', handler, false);
            }
        };
        return handler;
    }

    // @ts-ignore
    return new Promise<OAuthResult>((resolve, reject) => {
        if (_currentOauthResultsHandler) {
            window.removeEventListener('message', _currentOauthResultsHandler, false);
        }
        _currentOauthResultsHandler = createOAuthMessageHandler(resolve, reject);
        window.addEventListener(
            'message',
            _currentOauthResultsHandler,
            false,
        );
        window.open(
            getChallengeEndpoint(provider),
            undefined,
            'toolbar=no,menubar=no,directories=no,status=no,width=800,height=600',
        );
    });
}