CSV merge for coding test

csvmerge.go

package main

import (
	"encoding/csv"
	"fmt"
	"io"
	"log"
	"os"
	"strconv"
)

func main() {
	file1, err := os.Open("input1.csv")
	if err != nil {
		log.Fatalln("Couldn't open CSV file", err)
	}
	r1 := csv.NewReader(file1)

	file2, err := os.Open("input2.csv")
	if err != nil {
		log.Fatalln("Couldn't open CSV file", err)
	}
	r2 := csv.NewReader(file2)

	outputFile, err := os.Create("./output.csv")
	if err != nil {
		log.Fatal("Couldn't create output file", err)
	}

	writer := csv.NewWriter(outputFile)

	for {
		rec1, err1 := r1.Read()
		rec2, err2 := r2.Read()

		if err1 == io.EOF || err2 == io.EOF {
			break // End of file
		}
		if err1 != nil {
			log.Fatal("Error parsing row in input1.csv", err1)
		}
		if err2 != nil {
			log.Fatal("Error parsing row in input2.csv", err2)
		}

		if rec1[2] == "min_score" {
			row := []string{rec1[0], rec1[1], rec2[1], rec2[2]}
			if err := writer.Write(row); err != nil {
				log.Fatal("Failed to write to output file", err)
			}
		} else {
			minScore1, msErr1 := strconv.Atoi(rec1[2])
			minScore2, msErr2 := strconv.Atoi(rec2[2])

			if msErr1 != nil {
				log.Fatal("Error parsing min_score", msErr1)
			}

			if msErr2 != nil {
				log.Fatal("Error parsing min_score", msErr2)
			}

			var minScore int

			if minScore1 < minScore2 {
				minScore = minScore1
			} else {
				minScore = minScore2
			}
			row := []string{rec1[0], rec1[1], rec2[1], strconv.Itoa(minScore)}
			if err := writer.Write(row); err != nil {
				log.Fatal("Failed to write to output file", err)
			}
		}

		writer.Flush()

	}
}