var Cloudant = require('@cloudant/cloudant');
var fs = require('fs');
var cloudant;
var dbName;
var dbNameProcessed;

function main(params) {
    cloudant = Cloudant({account:params.USERNAME, password:params.PASSWORD});
    dbName = params.DBNAME;
    dbNameProcessed = params.DBNAME_PROCESSED;
    return new Promise(function(resolve, reject) {
        let mydb = cloudant.db.use(dbName);
        mydb.attachment.get(params.id, 'image', function(err, data) {
            if (err) {
                reject(err);
            } else {
                console.log(params)
                console.log(data)
                resolve(processImageToWatson(data,params.id,params.WATSON_VR_APIKEY));
            }
        });
    });
}

function processImageToWatson(data,id,apikey) {
    let filename = __dirname + '/' + id;
    fs.writeFileSync(filename, data)
    let VisualRecognitionV3 = require('watson-developer-cloud/visual-recognition/v3');
    var visualRecognition = new VisualRecognitionV3({
        version: '2018-03-19',
        iam_apikey: apikey,
    });

    var watsonvrparams = {
        images_file: fs.createReadStream(filename)
    };
    return new Promise(function(resolve, reject) {
        visualRecognition.classify(watsonvrparams, function(err, res) {
            if (err) {
                console.log(err);
                reject(err);
            } else {
                resolve(updateDocument(res,id));
            }
        });
    });
}

function updateDocument(watsonResult,id) {
    return new Promise(function(resolve, reject) {
        let mydb = cloudant.db.use(dbNameProcessed);
        var doc = {};
        doc._id = id
        doc.watsonResults = watsonResult.images[0].classifiers;
        mydb.insert(doc, function(err,body) {
            if (err) {
                reject(err);
            } else {
                console.log(body);
                resolve(body);
            }
        });
    });
}