const getParmvalByKey = function(url,_key,_separator){
    let _url = url || '';
    _separator = _separator || '?';
    _url = _url.trim();
    var _separatorIndex = _url.indexOf(_separator);
    if(_separatorIndex<0){
        return '';
    }

    if(_separator!='#'){
        var _index = _url.indexOf('#') || 0;
        if(_index>=0 && _separatorIndex<_index){
            _url = _url.substring(0,_index);
        }
    }
    _url = _url.substr(_separatorIndex+1);

    if (!_url) return '';
    _url = _url.split('&');
    for(var i=0,l=_url.length,d;i<l;i++){
        d = _url[i].indexOf('=');
        if(_url[i].substring(0,d) === _key){
            return _url[i].substr(d+1)||'';
        }
    }
    return '';
}

const setParmvalByKey = function(_url, key, value){
    let url = _url || '';
    url = url.trim();
    var separatorIndex = url.indexOf('?');
    var index = url.indexOf('#');
    var hash = '';
    if(index > 0){
        hash = '#' + url.split('#')[1]
        url = url.split('#')[0]
    }
    if(separatorIndex < 0){
        return url + '?' + key + '=' + value + hash;
    }else{
        var reg = new RegExp('(\\?|&)(' + key + '=(.+?))($|&|#)', 'g');
        url = reg.test(url) ? url.replace(reg, '$1' + key + '=' + value + '$4') : url + '&' + key + '=' + value;
        return url + hash;
    }
}

const getCmsPageId = function(){
    const pathName = window.location.pathname;
    let id = '';
    try {
        id = pathName.split('/')[2];
    } catch (e) {
        console.log(e);
        id = '0';
    }
    return id;
}

const genSpmString = ({name = '', a = 0,b = 0,c = 0,d = 0}) => {
    const cmsId = getCmsPageId();
    let spm = '';
    switch(name) {
        case 'spmCmspageCoupon': // cms页面-优惠券模块
            spm = `9.${cmsId}.1.0`;
            break;
        case 'spmCmspageProduct': // cms页面-商品模块
            spm = `9.${cmsId}.2.0`;
            break;
        default:
            spm = '';
    }
    return spm;
}

export function genSpmLink({url, name, a, b, c, d}){
    const adTrace = getParmvalByKey(location.href, 'adTrace', '?') || '';
    const spm = getParmvalByKey(location.href, 'spm', '?') || '';
    let newSpm = genSpmString({name, a,b,c,d});
    if (spm) {
        let spmsArr = spm.split('-');
        const lastSpm = spmsArr[spmsArr.length - 1]
        const lastSpmArr = lastSpm.split('.')
        if(newSpm) {
            const newSpmArr = newSpm.split('.')
            if(newSpmArr.length === 4 && newSpmArr.length === lastSpmArr.length ) {
                if (newSpmArr[0] === lastSpmArr[0]) { // 同一页面
                    spmsArr.splice(-1, 1, newSpm)
                } else {
                    spmsArr.push(newSpm)
                }
            }
        }
        newSpm = spmsArr.slice(-4).join('-');
    }
    let newSpmLink = setParmvalByKey(url, 'spm', newSpm);
    if (adTrace) {
        newSpmLink = setParmvalByKey(newSpmLink, 'adTrace', adTrace);
    }
    // console.log(adTrace, spm, newSpm, newSpmLink);
    return newSpmLink;
};