backend/src/services/trainService.services.js

const log     = require('../utils/logs.utils');
const db      = require('./dbAccess.services');
const clean   = require('../utils/sanitizer.utils');
const pis     = require('../services/pis.services');
const { filter } = require('compression');

async function findByHeadcodeToday(headcode) {
  const sanitizedHeadcode = clean.removeNonAlphanumeric(headcode).toUpperCase();
  log.out('trainServiceServices.findByHeadcode: Searching for headcode ' +
          sanitizedHeadcode, 'dbug');
  const now = new Date();
  const dayMap = ['su', 'm', 't', 'w', 'th', 'f', 's'];
  const shortDay = dayMap[now.getDay()]; // Fetch short day from map
  const query = {
    headcode: sanitizedHeadcode,
    scheduleStartDate: {$lte: now},
    scheduleEndDate: {$gte: now},
    daysRun: {$in: [shortDay]}
  };
  const queryData = await db.query('timetable', query);
  let trainData = await parseTrains(queryData);
  let preparedData = [];
  for (let trainService in trainData) {
    if (pis.supported.includes(trainService?.operator)) {
    // Search for PIS Code for each service
      const tiplocList = await getPublicStops(trainService?.stops);
      //console.log(tiplocList.length); console.log(tiplocList);
      if (tiplocList.length) {
        const pisDetail = await pis.findByTiplocArray(tiplocList);
        trainService['pis'] = pisDetail?.[0]?.['code'] ?? 'None';
      } else if (trainService?.operator === 'GW') {
        trainService['pis'] = '0015'; // Not in Service code
      // '0015' is a string becuase 0015 is not a valid number..
      }
    }
    preparedData.push(trainService);
  }
  return preparedData;
}

async function findByHeadcode(date, headcode) {
  const sanitizedHeadcode = clean.removeNonAlphanumeric(headcode).toUpperCase();
  log.out('trainServiceServices.findByHeadcode: Searching for headcode ' +
          sanitizedHeadcode, 'dbug');
  let searchDate;
  if (date === 'now') {
    searchDate = new Date();
  } else {
    searchDate = new Date(date);
  }
  searchDate.setHours(12,0,0); // Set to midday to avoid any timezone issues
  const dayMap = ['su', 'm', 't', 'w', 'th', 'f', 's'];
  const shortDay = dayMap[searchDate.getDay()]; // Fetch short day from map
  const query = {
    headcode: sanitizedHeadcode,
    scheduleStartDate: {$lte: searchDate},
    scheduleEndDate: {$gte: searchDate},
    daysRun: {$in: [shortDay]}
  };
  const pipeline = [
    {
      $match: query
    },
    {
      $project: {
        operator: 1,
        stops: {
          $concatArrays: [
            [{ $first: '$stops'}],
            [{ $arrayElemAt: ['$stops', -1]}]
          ]
        },
        trainUid: 1,
        stpIndicator: 1
      }
    }
  ];
  const queryData = await db.queryAggregate('timetable', pipeline);
  console.log(JSON.stringify(queryData));
  let filteredData = filterServices(queryData);
  return await filteredData;
}

async function findByTrainUid(uid, date = new Date()) {
  let queryDate;
  if (date === 'now') {
    queryDate = new Date();
  } else {
    queryDate = date;
  }
  const query = {
    trainUid: uid,
    scheduleStartDate: {$lte: queryDate},
    scheduleEndDate: {$gte: queryDate}
  };
  const queryData = await db.query('timetable', query);
  if (queryData.length === 0) {
    return [];
  }
  let services;
  services = await filterServices(queryData);
  console.log(services);
  let publicStops;
  if (pis.supported.includes(services[0]?.operator)) {
    publicStops = await getPublicStops(services[0]?.stops);
    if (publicStops.length) {
      const pisCode = await pis.findByTiplocArray(publicStops);
      services[0].pis = pisCode[0]?.code;
    } else if ( services[0]?.operator === 'GW' && !publicStops.length) {
      services[0].pis = '0015';
    }
  }
  return services[0];
}

module.exports = {
  findByHeadcodeToday,
  findByHeadcode,
  findByTrainUid
};

/* Internal Functions, not to be exported */

/* Accepts the 'stops' array from a db query and produces an
   array of only public stops as TIPLOCs. */
async function getPublicStops(data) {
  let tiplocList = [];
  for (const publicStop in data) {
    if (data[publicStop]['isPublic']) {
      tiplocList.push(data[publicStop]['tiploc']);
    }
  }
  return tiplocList;
}

/* Takes a single days data from a headcode query and requeries
   using the trainUid, required to ensure any cancellations are
   accounted for */
async function parseTrains(data) {
  let trainUids = [];
  for (const i of data) {
    const trainUid = i['trainUid'];
    if (!trainUids.includes(trainUid)) {
      trainUids.push(trainUid);
    }
  }
  let parsedData = [];
  for (const i in trainUids) {
    const result = await findByTrainUid(trainUids[i]);
    parsedData.push(result);
  }
  return parsedData;
}

async function filterServices(data) {
  let stpIndicators = {}, filteredServices = [];
  for (const serviceDetail of data) {
    const trainUid = serviceDetail['trainUid'];
    const stpIndicator = serviceDetail['stpIndicator'];
    if (!stpIndicators[trainUid]) {
      stpIndicators[trainUid] = {
        hasC: false,
        hasN: false,
        hasO: false,
        hasP: false
      };
    }
    if (stpIndicator === 'C') {
      stpIndicators[trainUid].hasC = true;
    }
    if (stpIndicator === 'N') {
      stpIndicators[trainUid].hasN = true;
    }
    if (stpIndicator === 'O') {
      stpIndicators[trainUid].hasO = true;
    }
    if (stpIndicator === 'P') {
      stpIndicators[trainUid].hasP = true;
    }
  }
  let preparedData;
  for (const serviceDetail of data) {
    const trainUid = serviceDetail['trainUid'];
    const thisStpIndicators = stpIndicators[trainUid];
    const stpIndicator = serviceDetail['stpIndicator'];

    if (stpIndicator === 'C') {
      break;
    }
    if (stpIndicator === 'N' && 
        !thisStpIndicators.hasC) {
      filteredServices.push(serviceDetail);

    } else if (stpIndicator === 'O' &&
               !thisStpIndicators.hasC &&
               !thisStpIndicators.hasN) {
      filteredServices.push(serviceDetail);

    } else if (stpIndicator === 'P' &&
               !thisStpIndicators.hasC &&
               !thisStpIndicators.hasN &&
               !thisStpIndicators.hasO) {
      filteredServices.push(serviceDetail);
    }
  }
  return filteredServices;
}