export type Navigator = NavigatorNetworkInformation;
export declare interface NavigatorNetworkInformation {
    readonly connection?: NetworkInformation;
}
type Megabit = number;
type Millisecond = number;
export type EffectiveConnectionType = '2g' | '3g' | '4g' | 'slow-2g' | 'unknown';
export type ConnectionType = 'bluetooth' | 'cellular' | 'ethernet' | 'mixed' | 'none' | 'other' | 'unknown' | 'wifi' | 'wimax';

export interface NetworkInformation extends EventTarget {
    readonly type?: ConnectionType;
    readonly effectiveType?: EffectiveConnectionType;
    readonly downlinkMax?: Megabit;
    readonly downlink?: Megabit;
    readonly rtt?: Millisecond;
    readonly saveData?: boolean;
    onchange?: EventListener;
}

export function getNetworkType(): string {
    /* wired 有线
      bluetooth,
      wifi,
      2g,3g,4g,5g...,
      unkown
    */
    const ua = navigator.userAgent;
    const ut = (navigator as Navigator).connection as NetworkInformation;
    let utt = ut ? (ut.type ? ut.type.toLowerCase() : ut.effectiveType.toLowerCase()) : null;
    if (utt) {
        switch (
            utt //bluetooth,
        ) {
            case 'cellular':
            case 'wimax':
                utt = ut ? (ut.effectiveType ? ut.effectiveType.toLowerCase() : null) : null;
                break;
            case 'wifi':
                break;
            case 'ethernet':
                utt = 'wired';
                break;
            case 'none':
            case 'other':
            case 'unknown':
                utt = null;
                break;
            default:
                break;
        }
    }
    let networkStr = utt ? utt : ua.match(/NetType\/\w+/) ? ua.match(/NetType\/\w+/)[0] : 'unknown';
    networkStr = networkStr.toLowerCase().replace('nettype/', '');

    return networkStr ? (networkStr === '3gnet' ? '3g' : networkStr) : 'unknown';
}