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).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) {
    // Search for PIS Code for each service
    const tiplocList = await getPublicStops(trainData[trainService]['stops']);
    //console.log(tiplocList.length); console.log(tiplocList);
    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
      // '0015' is a string otherwise it is interpreted as octal 13.
    }
    preparedData.push(trainData[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);
  }
  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 queryData = await db.query('timetable', query);
  let trainData = await parseTrains(queryData);
  let preparedData = [];
  for (let trainService in trainData) {
    // Search for PIS Code for each service
    const tiplocList = await getPublicStops(trainData[trainService]['stops']);
    //console.log(tiplocList.length); console.log(tiplocList);
    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
      // '0015' is a string otherwise it is interpreted as octal 13.
    }
    preparedData.push(trainData[trainService]);
  }
  return preparedData;
}

module.exports = {
  findByHeadcodeToday,
  findByHeadcode
};

/* 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;
}

/* Queries using a trainUid and filters all schedules that
   have been over-ridden by overlays, cancellations and new
   schedules. */
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) {
    return [];
  }
  let stpIndicators = {};
  for (const serviceDetail of queryData) {
    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 queryData) {
    const trainUid = serviceDetail['trainUid'];
    const thisStpIndicators = stpIndicators[trainUid];
    const stpIndicator = serviceDetail['stpIndicator'];

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

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

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