const fs = require('fs')

let fp1: string = '' // data
let fp2: string = '' // output
// let fp3: string = '' // fingerprint

fs.readFile('data.txt', (err, fingerprint) => {
    if (err) throw err;
    fp1 = fingerprint.toString()
    // console.log(fp1.length);
})
fs.readFile('fingerprint.txt', (err, fingerprint) => {
    if (err) throw err;
    fp2 = fingerprint.toString()
    // console.log(fp2.length);
})
// fs.readFile('fingerprint.txt', (err, fingerprint) => {
//     if (err) throw err;
//     fp3 = fingerprint.toString()
//     // console.log(fp3);
// })

const mismatches: number = compareAndCountDifferences(fp1, fp2);
console.log(`Number of mismatches: ${mismatches}`); 

function compareAndCountDifferences(str1, str2): number {
    // Length validation:
    if (str1.length !== 151440 || str2.length !== 151440) {
      console.log("Error: Strings must be exactly 151440 characters long")
    }
  
    // Character comparison and difference counting:
    let differenceCount = 0;
    for (let i = 0; i < str1.length; i++) {
      if (str1[i] !== str2[i]) {
        differenceCount++;
      }
    }
  
    return differenceCount;
  }