package main

import (
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"strconv"
)

type puzzle interface {
	solve1(r io.Reader) string
	solve2(r io.Reader) string
}

var (
	// pick which day to run with a flag
	day = flag.String("d", "", "which day to solve")

	// slice of all puzzles
	puzzles = []puzzle{
		&day01{},
	}
)

func inputs(day int) [2]io.Reader {
	inputs := [2]io.Reader{}
	path1 := fmt.Sprintf("input/%d-1", day)
	path2 := fmt.Sprintf("input/%d-2", day)

	f1, err := os.Open(path1)
	if err == nil {
		inputs[0] = f1
	}
	f2, err := os.Open(path2)
	if err == nil {
		inputs[1] = f2
	}
	return inputs
}

func main() {
	flag.Parse()
	puzzleIndex, err := strconv.Atoi(*day)
	if err != nil {
		log.Fatalf("invalid puzzle day: %s", *day)
	}
	inputs := inputs(puzzleIndex)

	puzzle := puzzles[puzzleIndex-1]

	fmt.Fprintf(os.Stdout, "Solution 1:\n%s\n", puzzle.solve1(inputs[0]))
	fmt.Fprintf(os.Stdout, "Solution 2:\n%s\n", puzzle.solve2(inputs[1]))
}