/**
 *
 * index.js
 *
 */
const dttime = require('date-utils');
const fs = require('fs');
const readline = require('readline');
const {google} = require('googleapis');

/**
 * constants
 */
const postpass='1234';
const sep1=',';
const sep2='at';
const datesep='-'
const timesep=' ';
const replacedatespec='{{ date }}';
const linefeed="\n";
const mdh2='## ';

const BaseDir = '/srv/blog';
const GDriveDir = '/home/user1/GDrive';
const templateMdFile = BaseDir + '/source/_drafts/template-one-liner.md';
const productionMdFile = BaseDir + '/source/_posts/one-liner.md';
const hexoGenerateFile = GDriveDir + '/sync/hexo_generate.txt';

// If modifying these scopes, delete token.json.
const SCOPES = ['https://www.googleapis.com/auth/spreadsheets.readonly'];
// The file token.json stores the user's access and refresh tokens, and is
// created automatically when the authorization flow completes for the first
// time.
const TOKEN_PATH = 'token.json';

const CREDENTIAL_PATH = 'credentials.json';

/**
 *
 * main
 *
 */
// Load client secrets from a local file.
fs.readFile(CREDENTIAL_PATH, (err, content) => {
    if (err) return console.log('Error loading client secret file:', err);
    // Authorize a client with credentials, then call the Google Sheets API.
    authorize(JSON.parse(content), updateTweet);
});

/**
 *
 * functions
 *
 */
//Month Name to Number 
function setMonth2Num(month) {
    let monthNameArray = ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec',];
    return (monthNameArray.indexOf(month) + 1);
}

//Optimize Description
function setDescFormat(str){
    let desc=str.substring(2).replace(/ /g, '');
    return desc;
}

//Optimize Password
function setPassFormat(str){
    let isValid=false;
    let validatestr=('0000'+str).slice(-4);
    //console.log(validatestr);
    if(validatestr==postpass){
        isValid=true;
    }
    return isValid;
}

//Optimize Date
function setDateFormat(dt){
    let date1=dt.substring(dt.indexOf(sep1) + 2, dt.indexOf(sep2) - 1)
        +datesep
        +dt.substring(0,dt.indexOf(sep1)).replace(/ /,datesep)
        +timesep
        +dt.substring(dt.indexOf(sep2) + 3);
    let monthbyStr=date1.substring(5,8);
    let monthbyNum=setMonth2Num(monthbyStr);
    date1=date1.replace(/[AP]M/,'');
    date1=date1.replace(monthbyStr,monthbyNum);
    //console.log(new Date().toFormat(date1));
    return new Date().toFormat(date1);
}

//check if file exists
function checkFileExist(filespec){
    let isExist = false;
    try{
        fs.statSync(filespec);
        isExist = true;
    }catch(err){
        isExist = false;
    }
    return isExist;
}

/**
 * Create an OAuth2 client with the given credentials, and then execute the
 * given callback function.
 * @param {Object} credentials The authorization client credentials.
 * @param {function} callback The callback to call with the authorized client.
 */
function authorize(credentials, callback) { 
    const {client_secret, client_id, redirect_uris} = credentials.installed;
    const oAuth2Client = new google.auth.OAuth2(
        client_id, client_secret, redirect_uris[0]);

    // Check if we have previously stored a token.
    fs.readFile(TOKEN_PATH, (err, token) => {
        if (err) return getNewToken(oAuth2Client, callback);
        oAuth2Client.setCredentials(JSON.parse(token));
        callback(oAuth2Client);
    });
}

/**
 * Get and store new token after prompting for user authorization, and then
 * execute the given callback with the authorized OAuth2 client.
 * @param {google.auth.OAuth2} oAuth2Client The OAuth2 client to get token for.
 * @param {getEventsCallback} callback The callback for the authorized client.
 */
function getNewToken(oAuth2Client, callback) {
    const authUrl = oAuth2Client.generateAuthUrl({
        access_type: 'offline',
        scope: SCOPES,
    });
    console.log('Authorize this app by visiting this url:', authUrl);
    const rl = readline.createInterface({
        input: process.stdin,
        output: process.stdout,
    });
    rl.question('Enter the code from that page here: ', (code) => {
        rl.close();
        oAuth2Client.getToken(code, (err, token) => {
            if (err) return console.error('Error while trying to retrieve access token', err);
            oAuth2Client.setCredentials(token);
            // Store the token to disk for later program executions
            fs.writeFile(TOKEN_PATH, JSON.stringify(token), (err) => {
                if (err) return console.error(err);
                console.log('Token stored to', TOKEN_PATH);
            });
            callback(oAuth2Client);
        });
    });
}

/**
 *
 * Post Tweeting
 *
 */
function updateTweet(auth) {
    const sheets = google.sheets({version: 'v4', auth});
    sheets.spreadsheets.values.get({
        spreadsheetId: 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX',
        range: 'Sheet1!A1:C',
    }, (err, res) => {
        if (err) return console.log('The API returned an error: ' + err);
        const rows = res.data.values;
        let tweetData={date:[], valid:[], description:[], rawdata: []};
        if (rows.length) {
            //console.log('Date, Pass, RawData');
            rows.map((row) => {
                //console.log(`${row[0]}, ${row[1]}, ${row[2]}`);
                tweetData.date.unshift(setDateFormat(row[0]));
                tweetData.valid.unshift(setPassFormat(row[1]));
                tweetData.description.unshift(setDescFormat(row[2]));
                tweetData.rawdata.unshift(row[2]);
            });
            if(tweetData.date.length>0){
                //console.log(tweetData);
                doPost(tweetData);
            }
        } else {
            console.log('No data found.');
        }
    });
}

/**
 *
 * Post
 *
 */
function doPost(tweetData){
    if(checkFileExist(templateMdFile)){
        fs.readFile(templateMdFile, (err, databuf)=>{
            //console.log(tweetData);
            for(let i=0;i<20;i++){
                if(tweetData.valid[i]){
                    databuf+=linefeed
                        +mdh2
                        +tweetData.date[i]
                        +linefeed
                        +linefeed
                        +tweetData.description[i]
                        +linefeed;
                }
            }
            databuf=databuf.replace(replacedatespec, tweetData.date[0]);
            //console.log(databuf);
            fs.readFile(productionMdFile, (err, postbuf)=>{
                if(postbuf==databuf){
                    console.log('nothing was updated.');
                }else{
                    fs.writeFile(productionMdFile, databuf, ()=>{
                        console.log('production file['+productionMdFile+'] was generated.');
                        fs.writeFile(hexoGenerateFile, '', ()=>{
                            console.log('hexo trigger file was generated.');
                        });
                    });
                }
            });
        });
    }else{
        console.log('template file['+templateMdFile+'] was not found.');
        return false;
    }
}