RyCooder - Command Line Music Player written in Swift

rycooder.swift

import Foundation
import AVFoundation

// AudioPlayer Class Definition
class AudioPlayer: NSObject {

    private let runLoop: NSRunLoop = NSRunLoop.currentRunLoop()
    private let stdinHandle: NSFileHandle = NSFileHandle.fileHandleWithStandardInput()
    private let items: [AVPlayerItem]!
    private var queuePlayer: AVQueuePlayer!

    init(contentPath: String) {
        super.init()
        
        let musicFiles = musicFilesInDirectory(contentPath)
        logMusicFiles(musicFiles)

        items = preparePlayerItemsWithPaths(musicFiles)
        queuePlayer = AVQueuePlayer.queuePlayerWithItems(items) as AVQueuePlayer
    }

    deinit {
        NSNotificationCenter.defaultCenter().removeObserver(self)
    }

    private func handleInput() {
        if let inputString = NSString(data: stdinHandle.availableData, encoding: NSUTF8StringEncoding) {
            var input = inputString.stringByReplacingOccurrencesOfString("\n", withString:"")
        
            var handledAsNumber = false
            if let inputNumber = input.toInt() {
                if inputNumber > 0 && inputNumber <= items.count {
                    jumpToItemAtIndex(inputNumber - 1)
                    queuePlayer.play()
                    handledAsNumber = true
                }
            }
            
            if handledAsNumber == false {
                switch input {
                case "start":
                    logStart()
                    queuePlayer.play()
                case "next":
                    queuePlayer.advanceToNextItem()
                    queuePlayer.play()
                case "previous":
                    jumpToPreviousItem()
                    queuePlayer.play()
                default:
                    println("Unrecognized selector \"\(input)\" 😦 .")
                }
            }
        }

        stdinHandle.waitForDataInBackgroundAndNotify()
        logInputTips()
    }

    func start() {
        handleInput()
        NSNotificationCenter.defaultCenter().addObserverForName(
                                           NSFileHandleDataAvailableNotification, 
                                           object: nil, 
                                           queue: NSOperationQueue.mainQueue()) {
                                               (notification) in
                                               self.handleInput()                           
                                           }

        runLoop.run()
    }

    private func jumpToItemAtIndex(index: Int) {
        queuePlayer.removeAllItems()
        for (_, item) in enumerate(items) {
            item.seekToTime(kCMTimeZero)
            queuePlayer.insertItem(item, afterItem: nil)
        }

        var i = 0
        while i < index {
            queuePlayer.advanceToNextItem()
            i++
        }
    }

    private func jumpToPreviousItem() {
        
    }

    private func logMusicFiles(musicFiles: [String]) {
        println("Music added to player queue:")
        for (index, musicPath) in enumerate(musicFiles) {
            println("#\(index + 1) -  \(musicPath.lastPathComponent)")
        }
        println("\n===== Type \"start\" to begin.")
    }

    private func logStart() {
        println("\n=====> 🎵  RyCooder has taken the stage...")
    }

    private func logInputTips() {
        println("\nType \"next\" or \"previous\" to change song.")
        println("Type index number to play that song.")
    }

    private func preparePlayerItemsWithPaths(musicPaths: [String]) -> [AVPlayerItem] {
        var items: [AVPlayerItem] = []
        for (_ , musicPath) in enumerate(musicPaths) {
            let itemURL = NSURL.fileURLWithPath(musicPath)
            let playerItem = AVPlayerItem(URL: itemURL)
            items.append(playerItem)
        }
        
        return items
    }

    private func musicFilesInDirectory(dirPath: String) -> [String] {
        var result: [String] = []

        if let directoryEnumerator = NSFileManager.defaultManager().enumeratorAtPath(dirPath) {
            let isMusicFile: String -> Bool = {
                fileName in
                let pathExtension = fileName.pathExtension
                return pathExtension == "m4a" ||
                       pathExtension == "mp3"
            }

            var fileName: String?
            let fileEnumeration: Void -> Void = {
                fileName = directoryEnumerator.nextObject() as? String
                if let validFileName = fileName {
                    if isMusicFile(validFileName) {
                        let fullPath = dirPath.stringByAppendingPathComponent(validFileName) 
                        result.append(fullPath)
                    }
                }
            }

            fileEnumeration()
            while fileName != nil {
                fileEnumeration()
            }
        }

        return result
    }

}

// Script
let path = NSFileManager.defaultManager().currentDirectoryPath
AudioPlayer(contentPath: path).start()