'use strict';

var utils = require('./lib/utils');
var fetch = require('node-fetch');
var format = require('util').format;
var debug = require('debug')('audit/rest-api-versions');
var deprecate = require('util').deprecate;
var NodeCache = require('node-cache');
var auditCache = new NodeCache();

var auditLog = deprecate(require('./lib/v1/audit-log'), 'Audit log v1 APIs are being deprecated. Use V2');
var auditLogV2 = require('./lib/v2/audit-log');

const AUDIT_V2_OPTIONS_CACHE_KEY = 'AUDIT_V2_OPTIONS';

function _getServiceOptions(credentials) {
  var uri = credentials.url + '/audit-log';
  var status = null;

  let cachedv2ServiceOptions = auditCache.get(`${AUDIT_V2_OPTIONS_CACHE_KEY}-${uri}`);
  if (cachedv2ServiceOptions) {
    return Promise.resolve(cachedv2ServiceOptions);
  }

  let options = {
    method: 'get',
    headers: { 'Content-Type': 'application/json' }
  };

  debug('Sending request to %s', uri);
  return fetch(uri, options).then(function (res) {
    status = res.status;
    return res.text();
  }).then(function (body) {
    try {
      body = JSON.parse(body);
    } catch (e) {
      body = null;
    }

    debug('Response status code: %d, Body: %j',status, body);
    if (status === 404) {
      throw new Error('URL not found');
    }

    if (status !== 200) {
      throw new Error(format('Status code %d received when checking supported REST API versions of Audit log server: %j', status, body));
    }

    var v2ServiceOptions = body.versions.find(function (element) {
      return credentials.user && credentials.password ? element.version === 'v2' : element.version === 'v2' && element.url.indexOf('oauth2') >= 0;
    });

    if (!v2ServiceOptions) {
      throw new Error('Audit log server does not support REST API v2');
    }

    let cachingResult = auditCache.set(`${AUDIT_V2_OPTIONS_CACHE_KEY}-${uri}`, v2ServiceOptions);
    if (!cachingResult) {
      debug('Failed to cache v2 service options. Retrying: %s', !cachingResult);
      cachingResult = auditCache.set(`${AUDIT_V2_OPTIONS_CACHE_KEY}-${uri}`, v2ServiceOptions);
    }

    return v2ServiceOptions;
  });
}

function _getAuditLogV2(credentials, securityContext) {
  if (credentials.logToConsole === true) {
    return Promise.resolve(auditLogV2(credentials, {}, securityContext));
  }
  return _getServiceOptions(credentials).then((serviceOptions) => {
    return auditLogV2(credentials, serviceOptions, securityContext);
  });
}

auditLog.v2 = function (credentials, securityContext, callback) {
  utils.validate.object(credentials, 'Credentials');
  if (arguments.length === 2){
    if (securityContext && !callback && typeof (securityContext) === 'function') {
      callback = securityContext;
      securityContext = null;
    }
    if (!securityContext) {
      securityContext = null;
    }
  }
  if (securityContext) {
    utils.validate.object(securityContext, 'SecurityContext');
  }
  if (callback) {

    utils.validate.callback(callback);
    _getAuditLogV2(credentials, securityContext).then((auditLogV2) => {
      return callback(null, auditLogV2);
    }).catch(callback);
  } else {
    return _getAuditLogV2(credentials, securityContext);
  }
};


module.exports = auditLog;