package main

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

// Possible algorithm
// First call the Genius API to get the lyrics
// Second scrape the Google search to get the musicmatch api version of the lyrics
// Compare two of them, If there are the same, print one, else print both files

// Possible flags -o (output) -versbose (print all debug) -search (the actual song you want to search)

var (
	printDebug bool
	useGenius  bool
	useGoogle  bool
	outputFile string
	errorLog   *log.Logger
	mainLog    *log.Logger
)

// flagsSet returns a set of all the flags what were actually set on the
// command line.
func flagsSet(flags *flag.FlagSet) map[string]bool {
	s := make(map[string]bool)
	flags.Visit(func(f *flag.Flag) {
		s[f.Name] = true
	})
	return s
}

func start() int {
	programName := os.Args[0]
	errorLog = log.New(os.Stderr, "", 0)
	mainLog = log.New(os.Stdout, "", 0)

	flags := flag.NewFlagSet(os.Args[0], flag.ExitOnError)
	flags.Usage = func() {
		out := flags.Output()
		fmt.Fprintf(out, "Usage: %v \n\n", programName)
		fmt.Fprint(out, "  This program is used to download lyrics for a song\n")
		fmt.Fprint(out, "  from the internet. There are two modes of operation.\n\n")
		fmt.Fprint(out, "  The first mode is scraping the lyrics from Google. So the operation is this: \n")
		fmt.Fprint(out, "  It first opens a chrome window, searches for the lyrics \n")
		fmt.Fprint(out, "  , and copies the lyrics returned by Google Search to a \n")
		fmt.Fprint(out, "  file defined by you.\n\n")
		fmt.Fprint(out, "  The second mode is getting the lyrics from Genius API. So the operation is this: \n")
		fmt.Fprint(out, "  It then tries to get search for the same song using the \n")
		fmt.Fprint(out, "  Genius API. It then tries to compare the lyrics with the \n")
		fmt.Fprint(out, "  Genius one.\n\n")
		flags.PrintDefaults()
	}

	outputFlag := flags.String("output", "", "Optional. Lyrics filename")
	verboseFlag := flags.Bool("verbose", false, "Optional. Turn on debug. Default is false.")
	searchFlag := flags.String("search", "", "Required. Name of song to search. If the name of the song is not a single word, put in quotes\"\"")
	helpFlag := flags.Bool("help", false, "Optional. Print Usage")
	useGoogleFlag := flags.Bool("google", false, "Optional. Use google.")
	useGeniusFlag := flags.Bool("genius", false, "Optional. Use genius")
	configFileFlag := flags.String("configFile", "", "Optional. Use with genius")

	err := flags.Parse(os.Args[1:])
	if err != nil {
		errorLog.Printf("Err: %+v", err)
		return 1
	}

	if len(flags.Args()) > 1 {
		errorLog.Println("Error: too many command-line arguments")
		flags.Usage()
		return 1
	}

	allSetFlags := flagsSet(flags)

	if allSetFlags["help"] && (allSetFlags["output"] || allSetFlags["search"] || allSetFlags["verbose"]) {
		errorLog.Println("Error: if -help is set, -output, -search and -verbose must remain unset")
		flags.Usage()
		return 1
	}

	if !allSetFlags["google"] && !allSetFlags["genius"] {
		errorLog.Println("Error: One of -google or -genius must be set")
		flags.Usage()
		return 1
	}

	if allSetFlags["google"] && allSetFlags["genius"] {
		errorLog.Println("Error: if -google is set, -genius must remain unset and vice versa")
		flags.Usage()
		return 1
	}

	if allSetFlags["google"] && allSetFlags["configFile"] {
		errorLog.Println("Error: if -google is set, -configFile must remain unset and vice versa")
		flags.Usage()
		return 1
	}

	if *helpFlag {
		flags.Usage()
		return 0
	}

	songToSearch := *searchFlag

	if len(songToSearch) == 0 {
		errorLog.Println("Error: the song name must be provided for search")
		flags.Usage()
		return 1
	}

	if allSetFlags["output"] {
		outputFile = *outputFlag
	} else {
		mainLog.Printf("Using %s as the name of the file(s) for downloaded lyrics..\n", songToSearch)
		outputFile = fmt.Sprintf("%s_lyrics", songToSearch)
	}

	printDebug = *verboseFlag
	if printDebug {
		mainLog.Printf("Output flag: %s, Debug flag: %t, Search flag: %s\n", outputFile, printDebug, songToSearch)
	}

	useGenius = *useGeniusFlag
	useGoogle = *useGoogleFlag

	if useGoogle {
		err := searchGoogle(songToSearch)
		if err != nil {
			errorLog.Printf("Err: %+v", err)
			return 1
		}
	}

	if useGenius {
		configFile := *configFileFlag
		config, err := getConfig(configFile)
		if err != nil {
			errorLog.Printf("Err: %+v", err)
			return 1
		}
		GENIUS_API_TOKEN = config.GeniusApiToken
		err = searchGenius(songToSearch)
		if err != nil {
			errorLog.Printf("Err: %+v", err)
			return 1
		}
	}

	return 0
}

func main() {
	os.Exit(start())
}