// Implementation of the 99 Bottles Of Beer song in Go.
package main

import (
	"fmt"
	"os"
	"strconv"
	"strings"
)

func main() {
	// Get argument for noOfBottles and convert to integer
	if len(os.Args) != 2 {
		fmt.Println("Usage: ./beer <no. of bottles>")
		fmt.Println("If a non-integer is passed, behaviour may be unexpected.")
		os.Exit(1)
	}
	noOfBottlesArg, _ := strconv.Atoi(os.Args[1])

	doRhyme(noOfBottlesArg)
}

// doRhyme outputs the rhyme with number of bottles specified in noOfBottles
func doRhyme(noOfBottles int) {
	// Assign parts of the rhyme to variables
	part1 := "%d bottles of beer"
	part2 := " on the wall,"
	part3 := "Take one down, pass it around, "
	// Loop untill 2 bottles of beer on the wall
	for noOfBottles > 1 {
		// First line
		fmt.Printf(part1+part2+" "+part1+",\n", noOfBottles, noOfBottles)
		if noOfBottles == 2 {
			// Make part1 singular, so the second line of the
			// ...second last verse is correct
			part1 = strings.Replace(part1, "s", " ", -1)
		}
		// Second line
		fmt.Printf(part3+part1+part2+"\n", noOfBottles-1)
		noOfBottles--
	}
	// Last verses
	fmt.Println("1 bottle of beer on the wall, 1 bottle of beer, ")
	fmt.Println("Take one down, pass it around, no more bottles of beer on the wall!")
	fmt.Println("No more bottles of beer on the wall, no more bottles of beer,")
	fmt.Println("We've taken them down and passed them around; now we're drunk and passed out!")
}