backend/src/services/trainService.services.js

const log     = require('../utils/log.utils');
const db      = require('./dbAccess.services');
const clean   = require('../utils/sanitizer.utils');
const pis     = require('../services/pis.services');

async function findByHeadcodeToday(headcode) {
  const sanitizedHeadcode = clean.removeNonAlphanumeric(headcode);
  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 (const trainService in trainData) {
    // Search for PIS Code for each service
    const tiplocList = await getPublicStops(trainData[trainService]['stops']);
    if (tiplocList.length) {
      const pisDetail = await pis.findByTiplocArray(tiplocList);
      trainData[trainService]['pis'] = pisDetail?.[0]?.['code'] ?? 'None';
    } else {
      trainData[trainService]['pis'] = '0015'; // Not in Service code
    }
    preparedData.push(trainData[trainService]);
  }
  return preparedData;
}

module.exports = {
  findByHeadcodeToday,
};

/* Internal Functions, not to be exported */

async function getPublicStops(data) {
  let tiplocList = [];
  for (const publicStop in data) {
    if (data[publicStop]['isPublic']) {
      tiplocList.push(data[publicStop]['tiploc']);
    }
  }
  return tiplocList;
}

async function parseTrains(data) { // Takes a single days data from a headcode query and returns only relevant services
  let trainUids = [];
  for (const i in data) {
    const trainUid = data[i]['trainUid'];
    if (!trainUids.includes(trainUid)) {
      data.push(trainUid);
    }
  }
  let parsedData = [];
  for (const i in trainUids) {
    const result = await findByTrainUid(trainUids[i]);
    parsedData.push(result);
  }
  return parsedData;
}

async function findByTrainUid(uid, date = new Date()) { // Date defaults to today
  const query = {
    trainUid: uid,
    scheduleStartDate: {$lte: date},
    scheduleEndDate: {$gte: date}
  };
  const queryData = await db.query('timetable', query);
  let c = [];
  let n = [];
  let o = [];
  let p = [];
  for (const serviceDetail of queryData) {
    const trainUid = serviceDetail['trainUid'];
    switch (serviceDetail['stpIndicator']) { // This won't work without further post procesing
    case 'C':
      c.push(trainUid);
      break;
    case 'N':
      if (!c.includes(trainUid)) {
        n.push(trainUid);
      }
      break;
    case 'O':
      if (!c.includes(trainUid) && !n.includes(trainUid)) {
        o.push(trainUid);
      }
      break;
    case 'P':
      if (!c.includes(trainUid) && !n.includes(trainUid) && !o.includes(trainUid)) {
        p.push(trainUid);
      }
      break;
    }
  }
}

/* Thoughts:
async function findByTrainUid(uid, date = new Date()) {
  const query = {
    trainUid: uid,
    scheduleStartDate: { $lte: date },
    scheduleEndDate: { $gte: date }
  };

  const queryData = await db.query('timetable', query);

  if (queryData.length === 0) {
    // Handle empty queryData
    return {
      c: [],
      n: [],
      o: [],
      p: []
    };
  }

  const trainUidSet = new Set();
  const trainUidStatus = {}; // Track the status of each trainUid

  for (const serviceDetail of queryData) {
    const trainUid = serviceDetail['trainUid'];
    const stpIndicator = serviceDetail['stpIndicator'];

    if (!trainUidStatus[trainUid]) {
      trainUidStatus[trainUid] = {
        hasO: false,
        hasN: false,
        hasC: false
      };
    }

    if (stpIndicator === 'O') {
      trainUidStatus[trainUid].hasO = true;
    } else if (stpIndicator === 'N') {
      trainUidStatus[trainUid].hasN = true;
    } else if (stpIndicator === 'C') {
      trainUidStatus[trainUid].hasC = true;
    }

    trainUidSet.add(trainUid);
  }

  const c = [];
  const n = [];
  const o = [];
  const p = [];

  for (const serviceDetail of queryData) {
    const trainUid = serviceDetail['trainUid'];
    const stpIndicator = serviceDetail['stpIndicator'];

    if (stpIndicator === 'C') {
      continue; // Skip 'C' entries
    }

    if (stpIndicator === 'N' && !trainUidStatus[trainUid].hasC) {
      n.push(trainUid);
    } else if (stpIndicator === 'O' && !trainUidStatus[trainUid].hasN && !trainUidStatus[trainUid].hasC) {
      o.push(trainUid);
    } else if (stpIndicator === 'P' && !trainUidStatus[trainUid].hasN && !trainUidStatus[trainUid].hasO && !trainUidStatus[trainUid].hasC) {
      p.push(trainUid);
    }
  }

  return {
    c,
    n,
    o,
    p
  };
}
*/