/**
 * 微信客户端。
 *
 * author: lyr
 * author: sand
 * since: 2016/11/25
 */
"use strict"

let https = require('https');

let configFile = require('../../include/commons').CONFIG_FILE;
let config = require('../../resources/config/' + configFile);

let log = require('../../util/log');

let WechatTokenRepo = require('../../repository/mysql/wechat.token.repo.js');

class WeChatClient {
    constructor() {
    }

    /**
     * 发送微信模板消息
     *
     * @param message {touser:"", template_id:"", url:"", data:{firts: {value:"", color:""}}}
     */
    static sendWxTemplateMessage(message, handler) {
        WehcatClient.getAccessToken(function (err, token) {
            if (err) {
                log.error("get access_token failed:" + err);
                return;
            }

            var opt = {
                host: 'api.weixin.qq.com',
                path: '/cgi-bin/message/template/send?access_token=' + token,
                method: 'POST'
            };

            var msg = JSON.stringify(message);
            log.info("sending wechat template message:" + msg);

            // 发送模板消息
            var req = https.request(opt, function (res) {
                res.setEncoding('utf8');
                var data = "";
                res.on('data', (d) => {
                    data += d;
                });
                res.on('end', () => {
                    var result = JSON.parse(data);

                    if (result && result.errcode === 0) {
                        log.info("send wechat template message success:" + msg);
                        if (handler) {
                            handler(null, result);
                        }
                    } else {
                        log.error("send wechat template message failed:" + msg);
                        if (handler) {
                            handler(result, null);
                        }
                    }
                });
                res.on('error', function (err) {
                    log.error('send wechat template message failed: ' + err.message);
                    if (handler) {
                        handler(err, null);
                    }
                });
            }).on('error', (e) => {
                log.error("send wechat template message failed:" + e.message);
                if (handler) {
                    handler(e, null);
                }
            });

            req.end(msg);
        });
    };

    /**
     * 获取微信access_token
     *
     * @param handler 回调函数
     */
    static getAccessToken(handler) {
        WechatTokenRepo.findOne(function (err, result) {
            if (err) {
                log.error("get wechat accessToken failed", err);
                return;
            }

            var data = result && result.length > 0 ? result[0] : null;
            var accessToken = "";

            if (data) {
                // 判断access_token是否有效
                if ((new Date().getTime() - data.add_timestamp) < (data.expires_in * 1000)) {
                    accessToken = data.access_token;
                }
            }

            // access_token为空时从微信新获取并执行回调，否则直接执行回调
            if (!accessToken) {
                var token_url = "https://api.weixin.qq.com/cgi-bin/token?";
                var params = "grant_type=client_credential&appid=" + config.wechatConfig.appId
                    + "&secret=" + config.wechatConfig.appSecret;

                // 从微信获取access_token
                https.get(token_url + params, function (res) {
                    var data = '';
                    res.on('data', (d) => {
                        data += d;
                    });

                    res.on('end', () => {
                        data = data ? JSON.parse(data) : {};
                        if (data.access_token) {
                            accessToken = data.access_token;
                            var expiresIn = data.expires_in;

                            WechatTokenRepo.save(accessToken, expiresIn, new Date(), function (err, result) {
                                if (err) {
                                    log.error("insert wechat access_token failed:" + err.message);
                                }
                            });

                            if (handler) handler(null, accessToken);
                        } else {
                            log.error("get wechat access_token failed:" + data);

                            if (handler) handler(data, null);
                        }
                    });
                }).on('error', (e) => {
                    log.error("get wechat access_token from wechat failed:" + e.message);
                    if (handler) handler(data, null);
                });
            } else {
                if (handler) handler(data, null);
            }
        });
    };
}

module.exports = WeChatClient;