"use strict";
  
  const request = require('request');
  const uuidv4 = require('uuid/v4');

  const moment = require('moment');

  
  const config = require('komodo-sdk/config');
  const logger = require('komodo-sdk/logger');
  
  const modems = require('./modems');

  const partnerLastSeen = require('./partner-last-seen');

  const history = require('./history');

  async function _getApproriateHandlerByLastSeen(partnerNumber) {
      logger.verbose('Looking for last seen on for partner number ' + partnerNumber);
      const lastSeenFrom = await partnerLastSeen.get(partnerNumber);
      return lastSeenFrom;
  }
  
  function _getApproriateHandlerByForced() {
      if (!config.sending_handler || !config.sending_handler.length) return;
  
      const sendingHandlerCount = config.sending_handler.length;
      const idx = Math.floor(Math.random() * sendingHandlerCount);
      return config.sending_handler[idx];
  }
  
  async function _getApproriateHandler(partnerNumber, origin) {
      let handlerToUse;
  
      if (config.handler_chooser_algorithm === 'FORCED') {
          handlerToUse = _getApproriateHandlerByForced();
          logger.verbose('Config file mentioned to using FORCED handler chooser algorithm', { handler_to_use: handlerToUse});
      }
      else {
          handlerToUse = await _getApproriateHandlerByLastSeen(partnerNumber);
          logger.verbose('Config file mentioned to using LAST-SEEN handler chooser algorithm', { handler_to_use: handlerToUse});
      }
  
      if (!modems.getModemConfig(handlerToUse, config.modems)) {
          const handlerWithSameOrigin = modems.getModemConfig(origin, config.modems);
          if (handlerWithSameOrigin) {
              logger.verbose('Invalid approriate handler, using handler from the same ORIGIN request by CORE to send sms')
              handlerToUse = origin;
          }
          else {
              logger.verbose('Invalid approriate handler, using default handler to send sms')
              handlerToUse = config.default_modem;
          }
      }
  
      return handlerToUse;
  }

  function _send(destinationNumber, msg, handlerName) {

      /*

      if (msg.length > 160 && !config.do_not_trim_long_sms) {
          logger.verbose('Message trim to 160 chars');
          msg = msg.slice(0, 156) + ' ...';
      }

      */

      if (msg.length > 160) {
          const newMsg = msg.slice(0, 160);
          const remainingMsg = msg.slice(160);

          _send(destinationNumber, newMsg, handlerName);
          setTimeout(() => {
              _send(destinationNumber, remainingMsg, handlerName);
          }, 2000);
  
          return;
      }

  
      const modem = modems.getModemConfig(handlerName, config.modems);
      if (!modem) {

          logger.warn('Not knowing modem to use. Ignoring message', { destination_number: destinationNumber, msg: msg, handler_name: handlerName });

          return;
      }
  
      if (!modem.url || !modem.apikey) {
          logger.warn('Invalid modem configuration', { config: modem, handler_name: handlerName });
          return;
      }

      const reqId = uuidv4();

      history.push({
          ts: moment().format('YYYY-MM-DD HH:mm:ss'), 
          modem: {
              name: handlerName,
          },
          direction: 'OUTGOING',
          partner: destinationNumber,
          message: msg,
      });

      const requestOptions = {
          url: modem.url,
          qs: {
              msg: msg,
              number: destinationNumber,
              reqid: reqId,
              apikey: modem.apikey
          }
      }

      logger.info('Sending message to modem handler', { req_id: reqId, destination_number: destinationNumber, msg: msg, msg_length: msg.length, handler_name: handlerName });

      request(requestOptions, function(err, res, body) {
          if (err) {
              logger.warn('Error requesting to modem handler. ' + err.toString(), { req_id: reqId, handler_name: handlerName });
              
          }
          else if (res.statusCode != 200) {
              logger.warn('Modem handler not responding with HTTP status code 200.', { http_status_code: res.statusCode, req_id: reqId, handler_name: handlerName });
          }
          else {
              logger.verbose('Message sent to handler', { req_id: reqId, handler_name: handlerName, response_body: body });
          }
      })

  
  }
  
  async function send(partner, msg, origin) {
      if (!partner) return;
  
      if (typeof msg !== 'string') {
          logger.warn('Message to send is not a string, ignoring message');
          return;
      }
  
      msg = msg.trim();
      if (!msg) return;
  
      const destinationNumber = modems.removeSuffixFromNumber(partner, config);
  
      logger.verbose('Choosing handler name', { partner: partner, msg: msg, origin: origin });
      let handlerName = ( await _getApproriateHandler(destinationNumber) );
  
      _send(destinationNumber, msg, handlerName);

  }
  
  exports.send = send;