package main

import (
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"path/filepath"
	"strconv"
)

type puzzle interface {
	solve(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 init() {
	flag.Parse()

}

func inputs(day int64) []io.Reader {
	inputs := make([]io.Reader, 0, 2)
	path := fmt.Sprintf("input/%d-[1-2]", day)

	matches, err := filepath.Glob(path)
	if err != nil {
		log.Fatalf("matching puzzle input files: %s", err.Error())
	}

	fmt.Println(matches)

	for _, match := range matches {
		f, err := os.Open(match)
		if err == nil {
			inputs = append(inputs, f)
		}
	}

	return inputs
}

func main() {
	puzzleIndex, err := strconv.ParseInt(*day, 10, 32)
	if err != nil {
		log.Fatalf("invalid puzzle day: %s", *day)
	}
	inputs := inputs(puzzleIndex)

	puzzle := puzzles[puzzleIndex-1]

	fmt.Fprintf(os.Stdout, "Day %d:\n", puzzleIndex)
	for i := range inputs {
		ans := puzzle.solve(inputs[i])
		fmt.Fprintf(os.Stdout, "Solution %d:\n%s", i+1, ans)
	}
	fmt.Fprintln(os.Stdout)
}