/**
 * guang
 * @author: lcy<chuanyang.liu@yoho.cn>
 * @date: 2016/09/01
 */

'use strict';

let fs = require('fs'),
    _ = require('lodash'),
    exphbs = require('express-handlebars').create(),
    Handlebars = exphbs.handlebars;/*,
    Pagination = require('../common/pagination');
*/

let ALL_TYPES= {
    'stand' : 'p-page-n',
    'mini' : 'p-n',
    'full' : 'f-p-page-n-l-info-input-gobtn', 
    'fullellipsis' : 'f-p-pe-n-l-info-input-gobtn',
    'ellipsis' : 'p-pe-n'
};

Handlebars.registerHelper("page", function(){
    var options = arguments[arguments.length - 1];
    var baseUrl = (arguments.length > 1 ? arguments[0] : null) || options.hash.baseUrl || '',
        page = (options.hash.page || 1)*1,
        showNum = (options.hash.showNum || 7)*1,
        pageSize= options.hash.pageSize || 20,
        totalPages   = options.hash.totalPages,
        totalRecords = options.hash.totalRecords,
        theme = options.hash.theme || 'pager',
        currentClass = options.hash.currentClass || 'cur',
        type = options.hash.type || 'stand',   //min full stand ellipsis  or: f-首页, p-上一页, page-页码，n-下一页，l-最后一页，info-displayMsg，inout输入框，gobtn-goto Btn
        pageVar = options.pageVar || 'page',
        pageSizeVar = options.pageSizeVar || "pageSize",
        base = baseUrl + (baseUrl.indexOf('?') < 0 ? '?' : '&') 
                       + (options.hash.pageSize ? (pageSizeVar + '=' + pageSize + '&') : '')
                       + pageVar + '=';

    if(!totalPages) {
        if(!totalRecords || !pageSize) {
            return new Handlebars.SafeString("");
        } else {
            totalPages = Math.ceil(totalRecords / pageSize);
        }
    }

    var items = ALL_TYPES[type] ? ALL_TYPES[type] : type;
    items = _.isArray(items) ? items : (items || ALL_TYPES.stand).split('-');

    var hasPage = false; //配置中如果配置了多次 page/pe 则将忽略，只第一次有效
    var ret = `<div class="pager ${theme}">`;
    items.forEach(function(val, index, arr){

        switch(val) {
            case 'f' : 
                if(page > 1) {
                    ret += `<a href="${base}1" title="首页">首页</a>`;
                }
                break;
            case 'p' : 
                if(page > 1) {
                    ret += `<a href="${base}` + (page - 1) + `" title="上一页">上一页</a>`;
                }
                break;
            case 'n' : 
                if(page < totalPages) {
                    ret += `<a href="${base}` + (page + 1) + `" title="下一页">下一页</a>`;
                }
                break;
            case 'l' : 
                if(page < totalPages) {
                    ret += `<a href="${base}${totalPages}" title="尾页">尾页</a>`;
                }
                break;
            case 'info' : 
                ret += `共{totalRecords}条/{totalPages}页`;
                break;
            case 'input' : 
                //input 
                //ret += '<span class="{cls}"><input value="{value}" type="text"></span>';
                break;
            case 'gobtn' : 
                //goto btn
                break;
            case 'page' : 
                if(!hasPage) ret += createStandItems();
                hasPage = true;
                break;
            case 'pe' : 
                if(!hasPage) ret += createEllipsisItems();
                hasPage = true;
                break;
        }
    });

    function createStandItems(){
        return renderItem(getPageNums());
    }

    function createEllipsisItems(){
        return renderItem(getPageNums('e'));
    }

    function getPageNums(type){
        var pageNums = [];
        var num = showNum;
        if(type == 'e') {
            num = num - 2;
            num = num > 2 ? num : 2;
        }

        /** 分页展示页码个数begin 规则：展示最靠近当前页的指定个数 **/
        var pageShowMax = num % 2 == 0 ? page - 1 : page;
        var pageShowMin = page;

        for(var i = 0; i < Math.floor(num/2); i++) {
            pageShowMax++;
            pageShowMin--;
            if(pageShowMax > totalPages) {
                pageShowMax = totalPages;
                if(pageShowMin > 1) {
                    pageShowMin--;
                }
            }
            if(pageShowMin < 1) {
                pageShowMin = 1;
                if(pageShowMax < totalPages) {
                    pageShowMax++;
                }
            }
        }

        for(var n = pageShowMin; n <= pageShowMax; n++) {
            pageNums.push(n);
        }

        if(type == 'e') {
            if(pageShowMin > 3) {
                pageNums.unshift(1, '.');
            } else if(pageShowMin == 2){
                pageNums.unshift(1);
            } else if(pageShowMin == 3) {
                pageNums.unshift(1, 2);
            }

            if(pageShowMax < totalPages - 2) {
                pageNums.push('.', totalPages);
            } else {
                for(var x = pageShowMax + 1; x <= totalPages; x++) {
                    pageNums.push(x);
                }
            }
        }

        return pageNums;
    }

    function renderItem(arr) {
        /** 分页展示页码个数end **/
        var ret = '';
        if(_.isArray(arr) && arr.length) {

            arr.forEach((val, index, arrs) => {
                if('.' == val) {
                    ret += '<a>...</a>';
                } else {
                    ret += `<a href="${base}${val}" ` + (page === val ? `class="${currentClass}"` : '') + ` title="第${val}页">${val}</a>`;
                }
            });
        }

        return ret;
    }

    if(options.fn) {
        ret += options.fn(options.context);
    }
    ret += '</div>';
    return new Handlebars.SafeString(ret);
});

exports = exphbs.handlebars;