var request = require('request');

function main(msg) {

    let eventMap = {
        CREATE: 'post',
        READ: 'get',
        UPDATE: 'put',
        DELETE: 'delete'
    };
    // for creation -> CREATE
    // for reading -> READ
    // for updating -> UPDATE
    // for deletion -> DELETE
    var lifecycleEvent = msg.lifecycleEvent;

    var endpoint = msg.apihost;
    var webparams = createWebParams(msg);

    var url = `https://${endpoint}/api/v1/web/whisk.system/cloudantWeb/changesWebAction.http`;

    if (lifecycleEvent in eventMap) {
        var method = eventMap[lifecycleEvent];
        return requestHelper(url, webparams, method);
    } else {
        return Promise.reject('unsupported lifecycleEvent');
    }
}

function requestHelper(url, input, method) {

    return new Promise(function(resolve, reject) {

        var options = {
            method : method,
            url : url,
            json: true,
            rejectUnauthorized: false
        };

        if (method === 'get') {
            options.qs = input;
        } else {
            options.body = input;
        }

        request(options, function(error, response, body) {

            if (!error && response.statusCode === 200) {
                resolve(body);
            }
            else {
                if (response) {
                    console.log('cloudant: Error invoking whisk action:', response.statusCode, body);
                    reject(body);
                }
                else {
                    console.log('cloudant: Error invoking whisk action:', error);
                    reject(error);
                }
            }
        });
    });
}

function createWebParams(rawParams) {
    var namespace = process.env.__OW_NAMESPACE;
    var triggerName = ':' + namespace + ':' + parseQName(rawParams.triggerName, '/').name;

    var webparams = Object.assign({}, rawParams);
    delete webparams.lifecycleEvent;
    delete webparams.bluemixServiceName;
    delete webparams.apihost;

    webparams.triggerName = triggerName;

    return webparams;
}

function parseQName(qname, separator) {
    var parsed = {};
    var delimiter = separator || ':';
    var defaultNamespace = '_';
    if (qname && qname.charAt(0) === delimiter) {
        var parts = qname.split(delimiter);
        parsed.namespace = parts[1];
        parsed.name = parts.length > 2 ? parts.slice(2).join(delimiter) : '';
    } else {
        parsed.namespace = defaultNamespace;
        parsed.name = qname;
    }
    return parsed;
}

exports.main = main;