/**
 * @desc: 计算密码复杂度(from:http://www.oschina.net/code/snippet_127301_17269)
 * @author: xuqi(qi.xu@yoho.cn)
 * @date: 2015/5/6
 */
function computeComplex(password) {
    var complex = 0;
    var length = password.length;

    var pre = '';
    var preType = 0;
    for (var i = 0; i < length; i++) {
        var cur = password.charAt(i);
        var curType = gettype(password, i);

        if (preType != curType || !isregular(cur, pre, curType)) {
            complex += curType + getcomplex(curType, preType);
        }

        pre = cur;
        preType = curType;
    }

    return complex;
}

function gettype(str, i) {
    if (str.charCodeAt(i) >= 48 && str.charCodeAt(i) <= 57) {
        return 1;
    }
    else if(str.charCodeAt(i) >= 97 && str.charCodeAt(i) <= 122) {
        return 2;
    }
    else if(str.charCodeAt(i) >= 65 && str.charCodeAt(i) <= 90) {
        return 3;
    }

    return 4;
}

function isregular(cur, pre, type) {
    var curCode = cur.charCodeAt(0);
    var preCode = pre.charCodeAt(0);

    if(curCode - preCode == 0){
        return true;
    }

    if(type != 4 && (curCode - preCode == 1 || curCode - preCode == -1)){
        return true;
    }

    return false;
}

function getcomplex(curType, preType){
    if(preType == 0 || curType == preType){
        return 0;
    }else if(curType == 4 || preType == 4){
        return 2;
    }else{
        return 1;
    }
}

module.exports = computeComplex;