a broken program for solving day 1

day1.go

package main

import (
	"bufio"
	"os"
	"regexp"
	"strconv"
	"strings"
)

func main() {
	data, err := os.Open("day1.txt")
	if err != nil {
		panic(err)
	}
	scanner := bufio.NewScanner(data)
	calibration := 0
	for scanner.Scan() {
		line := scanner.Text()
		first_number := ""
		last_number := ""

		// part 2
		// scan for the first matching named number and replace it, repeat until there's no more matches

		re := regexp.MustCompile(`(one|two|three|four|five|six|seven|eight|nine)`)
		for match := re.FindString(line); match != ""; match = re.FindString(line) {
			valueMap := make(map[string]rune)
			valueMap["one"] = '1'
			valueMap["two"] = '2'
			valueMap["three"] = '3'
			valueMap["four"] = '4'
			valueMap["five"] = '5'
			valueMap["six"] = '6'
			valueMap["seven"] = '7'
			valueMap["eight"] = '8'
			valueMap["nine"] = '9'

			if _, ok := valueMap[match]; !ok {
				panic(line + match)
			}
			line = strings.Replace(line, match, string(valueMap[match]), 1)
		}
		for _, c := range line {
			if _, err := strconv.Atoi(string(c)); err == nil {
				if first_number == "" {
					first_number = string(c)
				}
				last_number = string(c)
			}
		}
		number, err := strconv.Atoi(first_number + last_number)
		if err != nil {
			panic(err)
		}
		calibration += number
	}
	if err := scanner.Err(); err != nil {
		panic(err)
	}
	println("Calibration", calibration)
}