import (
	"bufio"
	"fmt"
	"os"
	"strings"
)

func check(e error) {
	if e != nil {
		panic(e)
	}
}

// Part 1
func parseLinePartOne(line string) int {
	var first, last int
	foundFirst := false
	for i := 0; i < len(line); i++ {
		if line[i] >= '0' && line[i] <= '9' {
			if !foundFirst {
				first = int(line[i] - '0')
				foundFirst = true
			}
			last = int(line[i] - '0')
		}
	}
	return first*10 + last
}

// Part 2
func stringToDigit(str string) (int, bool) {
	digits := map[string]int{
		"one":   1,
		"two":   2,
		"three": 3,
		"four":  4,
		"five":  5,
		"six":   6,
		"seven": 7,
		"eight": 8,
		"nine":  9,
	}
	if str[0] >= '0' && str[0] <= '9' {
		return int(str[0] - '0'), true
	}
	for k, v := range digits {
		if strings.HasPrefix(str, k) {
			return v, true
		}
	}
	return 0, false
}

func parseLinePartTwo(line string) int {
	first, last := 0, 0
	for i := 0; i < len(line); i++ {
		n, ok := stringToDigit(line[i:])
		if ok {
			first = n
			break
		}
	}
	for i := len(line) - 1; i >= 0; i-- {
		n, ok := stringToDigit(line[i:])
		if ok {
			last = n
			break
		}
	}
	return first*10 + last
}

func main() {
	file, err := os.Open("./input.txt")
	check(err)
	defer file.Close()

	scanner := bufio.NewScanner(file)
	partOne, partTwo := 0, 0
	for scanner.Scan() {
		line := scanner.Text()
		partOne += parseLinePartOne(line)
		partTwo += parseLinePartTwo(line)
	}
	check(scanner.Err())
	fmt.Println("Part 1:", partOne)
	fmt.Println("Part 2:", partTwo)
}