/**
 * Usage:
 */

var EVENT_STATUS = {
    ACTIVE: 'ACTIVE',
    SUSPENDED: 'SUSPENDED',
    TERMINATED: 'TERMINATED'
};

var isValidStatusCode = function(statusCode) {
    return statusCode >= 200 && statusCode <= 299;
};

var getEvents = function(status, propertyNames, propertyValues, formName) {  
    var formClause = formName ? '&form=' + encodeURIComponent(formName) : '';
  
    // Prepare the HTTP request to locate existing active events
    var getEvents = http.request({
        'endpoint': 'xMatters',
        'method': 'GET',
        'path': '/api/xm/1/events?status=' + status + '&propertyName=' + propertyNames.join(',') + '&propertyValue=' + propertyValues.join(',') + '&propertyValueOperator=EQUALS' + formClause,
        'headers': {
            'Content-Type': 'application/json'
        }
    });
    var response = getEvents.write();
    if(isValidStatusCode(response.statusCode)) {
        var events = [];
        if(response.body) {
            events = JSON.parse(response.body).data;
        } 
        return events;
    } else {
        throw 'getEvents returned an error: ' + response.statusCode;
    }
};

var terminateEvent = function(eventId) {
    var response = http.request({
        'endpoint': 'xMatters',
        'method': 'POST',
        'path': '/api/xm/1/events',
        'headers': {
            'Content-Type': 'application/json'
        }
    }).write({
        id: eventId,
        status: EVENT_STATUS.TERMINATED
    });
    if(isValidStatusCode(response.statusCode)) {
        return true;
    } else {
        return false;
    }
};

/**
 * Determine if an HTTP status code represents success
 *
 * @param {number} statusCode from an HTTP request
 * @returns {boolean} true if successful; false otherwise
 */
exports.isValidStatusCode = isValidStatusCode;

/**
 * Terminate active events matching a set of properties
 *
 * Note: When property is a string type, be sure to include the language
 *       with the property name (e.g. "alert_id#en"). If the property is
 *       a numeric, however, do not include the language (e.g.
 *       "alert_count").
 *
 * @param {Object} properties a set of properties to search
 * @param {string} formName name of the form that created the events
 * @returns {void}
 */
exports.terminateEvents = function (properties, formName) {
    // Prepare the search criteria for matching events
    var propNames = [];
    var propValues = [];
    for (var key in properties) {
        propNames.push(encodeURIComponent(key));
        propValues.push(encodeURIComponent(properties[key]));
    }

    if(propNames.length <= 0) {
        console.log('Skipping terminate events because it was called without any search properties');
        return false;
    }

    var isSuccessful = true;
    try {
        var activeEvents = getEvents(EVENT_STATUS.ACTIVE, propNames, propValues, formName);
        for(var i = 0; i < activeEvents.length; i++) {
            isSuccessful = terminateEvent(activeEvents[i].id) && isSuccessful;
        }
    } catch(e) {
        console.log('A problem occurred while terminating active events: ' + JSON.stringify(e));
        isSuccessful = false;
    }

    try {
        var suspendedEvents = getEvents(EVENT_STATUS.SUSPENDED, propNames, propValues, formName);
        for(var j = 0; j < suspendedEvents.length; j++) {
            isSuccessful = terminateEvent(suspendedEvents[j].id) && isSuccessful;
        }
    } catch(e) {
        console.log('A problem occurred while terminating suspended events: ' + JSON.stringify(e));
        isSuccessful = false;
    }

    return isSuccessful;
};