package main

import (
	"fmt"
	"log"
	"os"
	"strings"
)

func showUsage() {
	print(len(os.Args))
	fmt.Printf("Usage: %s <day> <part> [input.txt]\n", os.Args[0])
}

type DayPartSolver func([]string) error
type DaySolver struct {
	day1 DayPartSolver
	day2 DayPartSolver
}

func main() {
	if (len(os.Args) < 3) {
		showUsage()
		return
	}

	day := os.Args[1]
	part := os.Args[2]

	var input_filename string
	if len(os.Args) <= 3 {
		input_filename = "input.txt"
	} else {
		input_filename = os.Args[3]
	}

	contents, err := os.ReadFile(input_filename)
	if err != nil {
		log.Fatal(err)
	}

	lines := strings.Split(strings.TrimRight(string(contents), "\n"), "\n")

	solvers := make(map[string]DaySolver)
	solvers["1"] = DaySolver{ day1: Day1Part1, day2: Day1Part2 }
	solvers["2"] = DaySolver{ day1: Day2Part1, day2: Day2Part2 }
	solvers["3"] = DaySolver{ day1: Day3Part1, day2: Day3Part2 }
	solvers["4"] = DaySolver{ day1: Day4Part1, day2: Day4Part2 }

	solver, ok := solvers[day]

	if ok {
		var err error
		if part == "1" {
			err = solver.day1(lines)
		} else if part == "2" {
			err = solver.day1(lines)
		}

		if err != nil {
			log.Fatal(err)
		}
	} else {
		log.Fatal("Day not found")
	}
}