import Darwin
import ArgumentParser

@main
struct LyricliCommand: ParsableCommand {

    // Positional Arguments
    @Argument var artist: String?
    @Argument var trackName: String?

    // Flags
    @Flag(name: .shortAndLong, help: "Prints the version.")
    var version = false

    @Flag(name: [.long, .customShort("t")], help: "Shows title of track if true")
    var showTitle = false

    @Flag(name: .shortAndLong, help: "Lists all sources")
    var listSources = false

    // Named Arguments
    @Option(name: .shortAndLong, help: ArgumentHelp("Enables a source", valueName: "source"))
    var enableSource: String?

    @Option(name: .shortAndLong, help: ArgumentHelp("Disables a source", valueName: "source"))
    var disableSource: String?

    @Option(name: .shortAndLong, help: ArgumentHelp("Resets a source", valueName: "source"))
    var resetSource: String?

    mutating func run() throws {

        // Handle the version flag
        if version {
            print(Lyricli.version)
            Darwin.exit(0)
        }

        // Handle the list sources flag
        if listSources {
            Lyricli.printSources()
            Darwin.exit(0)
        }

        // Handle the enable source option
        if let source = enableSource {
            do {
                try Lyricli.enableSource(source)
            } catch let error {
                handleErrorAndQuit(error)
            }
            Darwin.exit(0)
        }

        // Handle the disable source option
        if let source = disableSource {
            do {
                try Lyricli.disableSource(source)
            } catch let error {
                handleErrorAndQuit(error)
            }
            Darwin.exit(0)
        }

        // Handle the reset source flag
        if let source = resetSource {
            do {
                try Lyricli.resetSource(source)
            } catch let error {
                handleErrorAndQuit(error)
            }
            Darwin.exit(0)
        }

        Lyricli.showTitle = showTitle

        if let artist {
            let currentTrack: Track
            if let trackName {
                currentTrack = Track(withName: trackName, andArtist: artist)
            } else {
                currentTrack = Track(withName: "", andArtist: artist)
            }
            Lyricli.printLyrics(currentTrack)
            Darwin.exit(0)
        }

        Lyricli.printLyrics()
    }

    private func handleErrorAndQuit(_ error: Error) {
        fputs(error.localizedDescription, stderr)
        Darwin.exit(1)
    }
}