package one

import (
	"bufio"
	"io"
	"strconv"
	"strings"
)

func mustConv(s string) int {
	n, err := strconv.Atoi(s)
	if err != nil {
		panic(err)
	}
	return n
}

func parseLines(r io.Reader) ([]equation, error) {
	equations := []equation{}

	scanner := bufio.NewScanner(r)
	for scanner.Scan() {
		parts := strings.Split(scanner.Text(), ":")
		res := mustConv(parts[0])
		var operands []int
		for _, s := range strings.Fields(parts[1]) {
			operands = append(operands, mustConv(string(s)))
		}
		equations = append(equations, newEquation(res, operands))
	}

	if err := scanner.Err(); err != nil {
		return nil, err
	}

	return equations, nil
}