/*
    205.395583333332 = 205°23'44.1"
    1，直接读取"度"：205
    2，(205.395583333332-205)*60=23.734999999920 得到"分"：23
    3，(23.734999999920-23)*60=44.099999995200 得到"秒"：44.1
    return string,
*/
function latLngDecimalToDegrees(decimal) {
    let absDecimal = Math.abs(decimal);
    let isNegative = Math.abs(decimal) != decimal;
    let d = Math.floor(absDecimal); //度
    let m = Math.floor((absDecimal - d) * 60);  //分
    let s = Math.round((absDecimal - d) * 3600 % 60);  //秒
    if(s == 60) {s = 0; m++}
    if(m == 60) {m = 0; d++}
    //d = ('000'+d).slice(-3);                   // left-pad with leading zeros
    m = ('00'+m).slice(-2);                    // left-pad with leading zeros
    s = ('00'+s).slice(-2);
    //if (s<10) s = '0' + s;                     // left-pad with leading zeros (note may include decimals)
    return (isNegative ? "-" : "") + d + '°' + m + "′" + s + '″';
}

/*
    Decimal Degrees = Degrees + minutes/60 + seconds/3600
    例：57°55'56.6" =57+55/60+56.6/3600=57.9323888888888
    return Float or NaN
*/
function latLngDegreesToDecimal(degreesStr) {
    let degreesArr = degreesStr.split("°");
    let degrees = degreesArr[0];
    let isNegative = Math.abs(degrees) != degrees;
    if (degreesArr.length == 1) {
        return parseInt(degrees);
    }

    let minutesArr = degreesArr[1].split("′");
    let minutes = minutesArr[0];
    if (minutesArr.length == 1) {
        return parseFloat((isNegative ? "-" : "") + (Math.abs(degrees) + Math.abs(minutes) / 60));
    }

    let secondsStr = minutesArr[1];
    let secondsArr = secondsStr.split('″');
    let seconds = secondsArr[0];

    return parseFloat((isNegative ? "-" : "") + (Math.abs(degrees) + Math.abs(minutes) / 60 + Math.abs(seconds) / 3600));
}

function isObject(arg) {
    return typeof arg === 'object' && arg !== null;
}

function isUndefined(arg) {
    return arg === void 0;
}

function isString(arg) {
    return typeof arg === 'string';
}

function hasLine(obj) {
    return (isObject(obj)
        && isSafeString(obj.lat)
        && isSafeString(obj.lng));
}

function isSafeString(arg) {
    if (isUndefined(arg)) {
        return false;
    }

    if (!isString(arg)) {
        return false;
    }

    if (arg.length == 0) {
        return false;
    }

    return true;
}

function hasPoint(obj) {
    return (isObject(obj)
        && isSafeString(obj.lat)
        && isSafeString(obj.lng));
}
module.exports = {
    latLngDecimalToDegrees,
    latLngDegreesToDecimal,
    isObject,
    isUndefined,
    isString,
    isSafeString,
    hasLine,
    hasPoint
}