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/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
'use strict';
 
const assert = require('assert');
const L = require('lodash');
 
module.exports = divideWork;
 
/**
 * Create a number of scripts for workers from the script given to use by user.
 */
function divideWork(script, numWorkers) {
  let newPhases = [];
  for (let i = 0; i < numWorkers; i++) {
    newPhases.push(L.cloneDeep(script.config.phases));
  }
 
  //
  // Adjust phase definitions:
  //
  L.each(script.config.phases, function(phase, phaseSpecIndex) {
    if (phase.arrivalRate && phase.rampTo) {
      let rates = distribute(phase.arrivalRate, numWorkers);
      let ramps = distribute(phase.rampTo, numWorkers);
      L.each(rates, function(Lr, i) {
        newPhases[i][phaseSpecIndex].arrivalRate = rates[i];
        newPhases[i][phaseSpecIndex].rampTo = ramps[i];
      });
      return;
    }
 
    if (phase.arrivalRate && !phase.rampTo) {
      let rates = distribute(phase.arrivalRate, numWorkers);
      L.each(rates, function(Lr, i) {
        newPhases[i][phaseSpecIndex].arrivalRate = rates[i];
      });
      return;
    }
 
    if (phase.arrivalCount) {
      let counts = distribute(phase.arrivalCount, numWorkers);
      L.each(counts, function(Lc, i) {
        newPhases[i][phaseSpecIndex].arrivalCount = counts[i];
      });
      return;
    }
 
    if (phase.pause) {
      // nothing to adjust here
      return;
    }
 
    console.log('Unknown phase spec definition, skipping.\n%j\n' +
                'This should not happen', phase);
  });
 
  //
  // Create new scripts:
  //
  let newScripts = L.map(L.range(0, numWorkers), function(i) {
    let newScript = L.cloneDeep(script);
    newScript.config.phases = newPhases[i];
    return newScript;
  });
 
  //
  // Adjust pool settings for HTTP if needed:
  //
  // FIXME: makes multicore code tightly coupled to the engines; replace with
  // something less coupled.
  if (!L.isUndefined(L.get(script, 'config.http.pool'))) {
    let pools = distribute(script.config.http.pool, numWorkers);
    L.each(newScripts, function(s, i) {
      s.config.http.pool = pools[i];
    });
  }
 
  return newScripts;
}
 
 
/**
 * Given M "things", distribute them between N peers as equally as possible
 */
function distribute(m, n) {
  m = Number(m);
  n = Number(n);
 
  let result = [];
 
  if (m < n) {
    for (let i = 0; i < n; i++) {
      result.push(i < m ? 1 : 0);
    }
  } else {
    let baseCount = Math.floor(m / n);
    let extraItems = m % n;
    for(let i = 0; i < n; i++) {
      result.push(baseCount);
      if (extraItems > 0) {
        result[i]++;
        extraItems--;
      }
    }
  }
  assert(m === sum(result), `${m} === ${sum(result)}`);
  return result;
}
 
function sum(a) {
  let result = 0;
  for(let i = 0; i < a.length; i++) {
    result += a[i];
  }
  return result;
}
 
Iif (require.main === module) {
  console.log(distribute(1, 4));
  console.log(distribute(1, 10));
  console.log(distribute(4, 4));
  console.log(distribute(87, 4));
  console.log(distribute(50, 8));
  console.log(distribute(39, 20));
  console.log(distribute(20, 4));
  console.log(distribute(19, 4));
  console.log(distribute(20, 3));
  console.log(distribute(61, 4));
  console.log(distribute(121, 4));
  console.log(distribute(32, 3));
  console.log(distribute(700, 31));
  console.log(distribute(700, 29));
}