// 获得对象的key
function getObjKeys(obj){
    if(obj !== Object(obj)){
        throw new TypeError('Invalid object');
    }
    var keys = [];
    for(var key in obj){
        if(Object.prototype.hasOwnProperty.call(obj, key)){
            keys[keys.length] = key;
        }
    }
    return keys;
}
function arrayCombine(targetArr){
    var resultArr = [];
    for(var n = 0; n <= targetArr.length; n++){
        var flagArrs = getFlagArrs(targetArr.length, n);
        while(flagArrs.length){
            var flagArr = flagArrs.shift();
            var combArr = Array(targetArr.length);
            for(var i = 0; i < targetArr.length; i++){
                if(flagArr[i]){
                    combArr[i] = targetArr[i];
                }
            }
            resultArr.push(combArr);
        }
    }
    return resultArr;
}
// 从m中取n的所有组合
function getFlagArrs(m, n) {
    var flagArrs = [],
        flagArr = [],
        isEnd = false;
    for(var i = 0; i < m; i++){
        flagArr[i] = i < n ? 1 : 0;
    }
    flagArrs.push(flagArr.concat());
    // 当n不等于0并且m大于n的时候进入
    if(n && m > n){
        while(!isEnd){
            var leftCnt = 0;
            for(var i = 0; i < m - 1; i++){
                if (flagArr[i] == 1 && flagArr[i + 1] == 0){
                    for(var j = 0; j < i; j++){
                        flagArr[j] = j < leftCnt ? 1 : 0;
                    }
                    flagArr[i] = 0;
                    flagArr[i + 1] = 1;
                    var aTmp = flagArr.concat();
                    flagArrs.push(aTmp);
                    if(aTmp.slice(-n).join('').indexOf('0') == -1){
                        isEnd = true;
                    }
                    break;
                }
                flagArr[i] == 1 && leftCnt++;
            }
        }
    }
    return flagArrs;
}
function initSKU(sku){
    var resultSKU = [];
    var skuKeys = getObjKeys(sku);
    for(var i in skuKeys){
        var skuKey = skuKeys[i]; // 获取一条SKU的key
        var skuData = sku[skuKey]; // 获取一条SKU的相关数据
        var skuKeyAttrs = skuKey.split(';'); // 获取SKU的key的属性数组
        var combArr = arrayCombine(skuKeyAttrs);
        for(var j = 0; j < combArr.length; j++){
            var key = combArr[j].join(';');
            if(resultSKU[key]){
                resultSKU[key].count += skuData.count;
                resultSKU[key].prices.push(skuData.price);
            }else{
                resultSKU[key] = {
                    count: skuData.count,
                    prices: [skuData.price]
                };
            }
        }
    }
    return resultSKU;
}
// 渲染DOM
function initDOM(key){
    var html = '';
    $(key).each(function(index, el) {
        html += '<div>';
            html += '<label>' + this.name + '：</label>';
            $(this.item).each(function(index, el) {
                html += '<input type="button" class="sku" value="' + this + '">';
            });
        html += '</div>';
    });
    $('#sku').html(html);
}
// 显示库存和价格
function showCountAndPrice(resultSKU){
    var sku = [];
    $('#sku div').each(function(index, el) {
        sku.push($(this).children('.selected').val() || '');
    });
    sku = sku.join(';');
    var maxPrice = Math.max.apply(Math, resultSKU[sku].prices);
    var minPrice = Math.min.apply(Math, resultSKU[sku].prices);
    $('#result').html('库存：' + resultSKU[sku].count + '<br>' + '价格：' + (maxPrice > minPrice ? minPrice + '-' + maxPrice : maxPrice));
}
// 校验相关SKU是否可选
function checkSKU(resultSKU){
    $('#sku div .sku').prop('disabled', false);
    var count = 0;
    var i = 0;
    $('#sku div').each(function(index, el) {
        if($(this).children('.selected').length == 0){
            count += 1;
            i = index;
        }
    });
    // 当只有一组属性没选时
    if(count == 1){
        $('#sku div:eq(' + i + ') .sku').each(function(index, el) {
            var sku = [];
            var text = $(this).val();
            $('#sku div').each(function(index, el) {
                if(index != i){
                    sku.push($(this).children('.selected').val());
                }else{
                    sku.push(text);
                }
            });
            if(resultSKU[sku.join(';')].count == 0){
                $(this).prop('disabled', true);
            }
        });
    }
    // 当所有属性都有选时
    if(count == 0){
        $('#sku div').each(function(index, el) {
            var i = index;
            $('#sku div:eq(' + index + ') .sku:not(.selected)').each(function(index, el) {
                var sku = [];
                var text = $(this).val();
                $('#sku div').each(function(index, el) {
                    if(index != i){
                        sku.push($(this).children('.selected').val());
                    }else{
                        sku.push(text);
                    }
                });
                if(resultSKU[sku.join(';')].count == 0){
                    $(this).prop('disabled', true);
                }
            });
        });
    }
    showCountAndPrice(resultSKU);
}
$(function(){
    // 属性集
    var key = [
        {name: '颜色', item: ['黑', '金', '白']},
        {name: '内存', item: ['16G', '32G']},
        {name: '运营商', item: ['电信', '移动', '联通']}
    ];
    // 数据集
    var sku = {
        '黑;16G;电信': {price: 100, count: 10},
        '黑;16G;移动': {price: 101, count: 11},
        '黑;16G;联通': {price: 102, count: 0},
        '黑;32G;电信': {price: 103, count: 13},
        '黑;32G;移动': {price: 104, count: 14},
        '黑;32G;联通': {price: 105, count: 0},
        '金;16G;电信': {price: 106, count: 16},
        '金;16G;移动': {price: 107, count: 17},
        '金;16G;联通': {price: 108, count: 18},
        '金;32G;电信': {price: 109, count: 0},
        '金;32G;移动': {price: 110, count: 20},
        '金;32G;联通': {price: 111, count: 21},
        '白;16G;电信': {price: 112, count: 0},
        '白;16G;移动': {price: 113, count: 23},
        '白;16G;联通': {price: 114, count: 24},
        '白;32G;电信': {price: 115, count: 0},
        '白;32G;移动': {price: 116, count: 26},
        '白;32G;联通': {price: 117, count: 27}
    };
    var resultSKU = initSKU(sku);
    initDOM(key);
    checkSKU(resultSKU);
    $('#sku input[type=button]:not(:disabled)').click(function(event) {
        $(this).toggleClass('selected').siblings().removeClass('selected');
        checkSKU(resultSKU);
    });
});