package main

import "core:fmt"
import "core:os"
import "core:strconv"
import "core:strings"
import "core:unicode/utf8"

main :: proc() {

	if len(os.args) < 2 {
		fmt.println("Error: file required")
		os.exit(-1)
	}
	filename := os.args[1]

	sum, ok := getSum(filename)
	if !ok {
		os.exit(-1)
	}
	fmt.println(sum)

}


getSum :: proc(filename: string) -> (int, bool) {
	data, err := os.read_entire_file(filename, context.allocator)
	if err != nil {
		fmt.println("error opening file", err)
		return -1, false
	}
	defer delete(data, context.allocator)
	sum := 0

	iter := string(data)

	for line in strings.split_lines_iterator(&iter) {
		first := getFirst(line)
		last := getLast(line)

		// convert to rune array
		digits := []rune{first, last}
		// convert rune array to string first?
		str := utf8.runes_to_string(digits, context.allocator)
		// covert string to int..
		val, ok := strconv.parse_int(str)
		if !ok {
			fmt.println("error converting to int")
			continue
		}
		sum += val

	}

	return sum, true
}

getFirst :: proc(line: string) -> rune {
	first: rune

	for ch in line {
		if ch >= '0' && ch <= '9' {
			first = ch
			break
		}
	}

	return first
}

getLast :: proc(line: string) -> rune {
	last: rune

	length := len(line) - 1
	for i := length; i >= 0; i -= 1 {
		if line[i] >= '0' && line[i] <= '9' {
			last = rune(line[i])
			break
		}

	}
	return last
}