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| 1 | +import {v4 as uuidv4} from "uuid" |
| 2 | +import pino from "pino" |
| 3 | +import {getSharedAuthToken, getBody} from "./helper/psu.mjs" |
| 4 | +import {allowedOdsCodes, blockedOdsCodes} from "./helper/odscodes.mjs" |
| 5 | + |
| 6 | +export { getSharedAuthToken } |
| 7 | + |
| 8 | +const logger = pino() |
| 9 | + |
| 10 | +const LETTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"; |
| 11 | +const DIGITS = "0123456789"; |
| 12 | + |
| 13 | +const randomChar = (chars) => chars[Math.floor(Math.random() * chars.length)]; |
| 14 | + |
| 15 | +/** Generate one two-letter, three-digit ODS code, e.g. "AB123" */ |
| 16 | +const generateOdsCode = () => |
| 17 | + `${randomChar(LETTERS)}${randomChar(LETTERS)}${randomChar(DIGITS)}${randomChar(DIGITS)}${randomChar(DIGITS)}`; |
| 18 | + |
| 19 | +function buildFullOdsCodes(targetCount, seedCodes) { |
| 20 | + const codes = new Set(seedCodes); |
| 21 | + |
| 22 | + while (codes.size < targetCount) { |
| 23 | + codes.add(generateOdsCode()); |
| 24 | + } |
| 25 | + |
| 26 | + return Array.from(codes); |
| 27 | +} |
| 28 | + |
| 29 | +// The complete list of ODS codes |
| 30 | +const fullOdsCodes = allowedOdsCodes.concat(blockedOdsCodes) |
| 31 | + |
| 32 | +function computeCheckDigit(nhsNumber) { |
| 33 | + const factors = [10,9,8,7,6,5,4,3,2] |
| 34 | + let total = 0 |
| 35 | + |
| 36 | + for (let i = 0; i < 9; i++) { |
| 37 | + total += parseInt(nhsNumber.charAt(i),10) * factors[i] |
| 38 | + } |
| 39 | + |
| 40 | + const rem = total % 11 |
| 41 | + let d = 11 - rem |
| 42 | + if (d === 11) d = 0 |
| 43 | + |
| 44 | + return d |
| 45 | +} |
| 46 | + |
| 47 | +function generateValidNhsNumber() { |
| 48 | + while (true) { |
| 49 | + const partial = Array.from({length:9},() => Math.floor(Math.random()*10)).join("") |
| 50 | + const cd = computeCheckDigit(partial) |
| 51 | + if (cd < 10) return partial + cd |
| 52 | + } |
| 53 | +} |
| 54 | + |
| 55 | +// Apparently Math.sampleNormal isn't a function? Do a quick Box-Muller transform instead |
| 56 | +function sampleNormal(mean = 0, sd = 1) { |
| 57 | + let u = 0, v = 0; |
| 58 | + // avoid zeros because of log(0) |
| 59 | + while (u === 0) u = Math.random(); |
| 60 | + while (v === 0) v = Math.random(); |
| 61 | + const z = Math.sqrt(-2 * Math.log(u)) * Math.cos(2 * Math.PI * v); |
| 62 | + return z * sd + mean; |
| 63 | +} |
| 64 | + |
| 65 | +export function initUser(context, events, done) { |
| 66 | + // Generate data for a patient |
| 67 | + context.vars.odsCode = fullOdsCodes[Math.floor(Math.random()*fullOdsCodes.length)] |
| 68 | + context.vars.nhsNumber = generateValidNhsNumber() |
| 69 | + |
| 70 | + let prescriptionCount = Math.round(sampleNormal(3,1)) |
| 71 | + if (prescriptionCount < 1) prescriptionCount = 1 // just truncate at 1. |
| 72 | + context.vars.prescriptionCount = prescriptionCount |
| 73 | + context.vars.loopcount = 0 |
| 74 | + |
| 75 | + logger.info(`Patient ${context.vars.nhsNumber}, ODS ${context.vars.odsCode} has ${context.vars.prescriptionCount} prescriptions`) |
| 76 | + |
| 77 | + done() |
| 78 | +} |
| 79 | + |
| 80 | +export function generatePrescData(requestParams, context, ee, next) { |
| 81 | + logger.debug(`Generating a prescription for patient ${context.vars.nhsNumber}`) |
| 82 | + const body = getBody( |
| 83 | + true, /* isValid */ |
| 84 | + "completed", /* status */ |
| 85 | + context.vars.odsCode, /* odsCode */ |
| 86 | + context.vars.nhsNumber, /* nhsNumber */ |
| 87 | + "ready to collect" /* Item status */ |
| 88 | + ) |
| 89 | + // The body is fine - it works when I put it in postman |
| 90 | + |
| 91 | + requestParams.json = body |
| 92 | + context.vars.x_request_id = uuidv4() |
| 93 | + context.vars.x_correlation_id = uuidv4() |
| 94 | + |
| 95 | + context.vars.loopcount += 1 |
| 96 | + |
| 97 | + // Wait this long between requests |
| 98 | + let meanDelay = 10 // seconds |
| 99 | + let stdDevDelay = 10 // seconds |
| 100 | + let delay = 0 |
| 101 | + if (context.vars.loopcount < context.vars.prescriptionCount) { |
| 102 | + delay = sampleNormal(meanDelay, stdDevDelay) |
| 103 | + while (delay < 0) delay = sampleNormal(meanDelay, stdDevDelay) |
| 104 | + } |
| 105 | + |
| 106 | + context.vars.nextDelay = delay |
| 107 | + logger.debug(`Patient ${context.vars.nhsNumber} (on prescription update ${context.vars.loopcount}/${context.vars.prescriptionCount}) will think for ${context.vars.nextDelay} seconds`) |
| 108 | + |
| 109 | + next() |
| 110 | +} |
| 111 | + |
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