CameraManager/camera/CameraManager.swift

//
//  CameraManager.swift
//  camera
//
//  Created by Natalia Terlecka on 10/10/14.
//  Copyright (c) 2014 imaginaryCloud. All rights reserved.
//

import UIKit
import AVFoundation
import AssetsLibrary

private let _singletonSharedInstance = CameraManager()

enum CameraDevice {
    case Front, Back
}

enum CameraFlashMode: Int {
    case Off, On, Auto
}

enum CameraOutputMode {
    case StillImage, VideoWithMic, VideoOnly
}

enum CameraOutputQuality {
    case Low, Medium, High
}

/// Class for handling iDevices custom camera usage
class CameraManager: NSObject, AVCaptureFileOutputRecordingDelegate {

    /// Capture session to customize camera settings.
    var captureSession: AVCaptureSession?

    /// Property to determine if the manager should show the error for the user. If you want to show the errors yourself set this to false. If you want to add custom error UI set showErrorBlock property. Default value is true.
    var showErrorsToUsers = true

    /// A block creating UI to present error message to the user.
    var showErrorBlock:(erTitle: String, erMessage: String) -> Void = { (erTitle: String, erMessage: String) -> Void in
        UIAlertView(title: erTitle, message: erMessage, delegate: nil, cancelButtonTitle: "OK").show()
    }

    /// Property to determine if  manager should write the resources to the phone library. Default value is true.
    var writeFilesToPhoneLibrary = true

    /// The Bool property to determin if current device has front camera.
    var hasFrontCamera: Bool = {
        let devices = AVCaptureDevice.devicesWithMediaType(AVMediaTypeVideo)
        for  device in devices  {
            let captureDevice = device as AVCaptureDevice
            if (captureDevice.position == .Front) {
                return true
            }
        }
        return false
    }()

    /// Property to change camera device between front and back.
    var cameraDevice: CameraDevice {
        get {
            return _cameraDevice
        }
        set(newCameraDevice) {
            if let validCaptureSession = self.captureSession {
                validCaptureSession.beginConfiguration()
                let inputs = validCaptureSession.inputs as [AVCaptureInput]

                switch newCameraDevice {
                case .Front:
                    if self.hasFrontCamera {
                        if let validBackDevice = self.rearCamera? {
                            if contains(inputs, validBackDevice) {
                                validCaptureSession.removeInput(validBackDevice)
                            }
                        }
                        if let validFrontDevice = self.frontCamera? {
                            if !contains(inputs, validFrontDevice) {
                                validCaptureSession.addInput(validFrontDevice)
                            }
                        }
                    }
                case .Back:
                    if let validFrontDevice = self.frontCamera? {
                        if contains(inputs, validFrontDevice) {
                            validCaptureSession.removeInput(validFrontDevice)
                        }
                    }
                    if let validBackDevice = self.rearCamera? {
                        if !contains(inputs, validBackDevice) {
                            validCaptureSession.addInput(validBackDevice)
                        }
                    }
                }
                validCaptureSession.commitConfiguration()
            }
            _cameraDevice = newCameraDevice
        }
    }

    /// Property to change camera flash mode.
    var flashMode: CameraFlashMode {
        get {
            return _flashMode
        }
        set(newflashMode) {
            if newflashMode != _flashMode {
                self.captureSession?.beginConfiguration()
                let devices = AVCaptureDevice.devicesWithMediaType(AVMediaTypeVideo)
                for  device in devices  {
                    let captureDevice = device as AVCaptureDevice
                    if (captureDevice.position == AVCaptureDevicePosition.Back) {
                        let avFlashMode = AVCaptureFlashMode(rawValue: newflashMode.rawValue)
                        if (captureDevice.isFlashModeSupported(avFlashMode!)) {
                            captureDevice.lockForConfiguration(nil)
                            captureDevice.flashMode = avFlashMode!
                            captureDevice.unlockForConfiguration()
                        }
                    }
                }
                self.captureSession?.commitConfiguration()

                _flashMode = newflashMode
            }
        }
    }

    /// Property to change camera output quality.
    var cameraOutputQuality: CameraOutputQuality {
        get {
            return _cameraOutputQuality
        }
        set(newCameraOutputQuality) {
            if newCameraOutputQuality != _cameraOutputQuality {
                if let validCaptureSession = self.captureSession? {
                    validCaptureSession.beginConfiguration()
                    switch (newCameraOutputQuality) {
                    case CameraOutputQuality.Low:
                        validCaptureSession.sessionPreset = AVCaptureSessionPresetLow
                    case CameraOutputQuality.Medium:
                        validCaptureSession.sessionPreset = AVCaptureSessionPresetMedium
                    case CameraOutputQuality.High:
                        validCaptureSession.sessionPreset = AVCaptureSessionPresetHigh
                    }
                    validCaptureSession.commitConfiguration()

                    _cameraOutputQuality = newCameraOutputQuality
                } else {
                    self._show("Camera error", message: "No valid capture session found, I can't take any pictures or videos.")
                }
            }
        }
    }

    /// Property to change camera output.
    var cameraOutputMode: CameraOutputMode {
        get {
            return _cameraOutputMode
        }
        set(newCameraOutputMode) {
            if newCameraOutputMode != _cameraOutputMode {
                self._setupOutputMode(newCameraOutputMode)
            }
        }
    }

    private weak var embedingView: UIView?
    private var videoCompletition: ((videoURL: NSURL) -> Void)?

    private var sessionQueue: dispatch_queue_t = dispatch_queue_create("CameraSessionQueue", DISPATCH_QUEUE_SERIAL)

    private var frontCamera: AVCaptureInput?
    private var rearCamera: AVCaptureInput?
    private var mic: AVCaptureDeviceInput?
    private var stillImageOutput: AVCaptureStillImageOutput?
    private var movieOutput: AVCaptureMovieFileOutput?
    private var previewLayer: AVCaptureVideoPreviewLayer?
    private var library: ALAssetsLibrary?

    private var cameraIsSetup = false
    private var cameraIsObservingDeviceOrientation = false

    private var _cameraDevice = CameraDevice.Back
    private var _flashMode = CameraFlashMode.Off
    private var _cameraOutputMode = CameraOutputMode.StillImage
    private var _cameraOutputQuality = CameraOutputQuality.High

    private var tempFilePath: NSURL = {
        let tempPath = NSTemporaryDirectory().stringByAppendingPathComponent("tempMovie").stringByAppendingPathExtension("mp4")
        if NSFileManager.defaultManager().fileExistsAtPath(tempPath!) {
            NSFileManager.defaultManager().removeItemAtPath(tempPath!, error: nil)
        }
        return NSURL(fileURLWithPath: tempPath!)!
        }()

    /// CameraManager singleton instance to use the camera.
    class var sharedInstance: CameraManager {
        return _singletonSharedInstance
    }

    deinit {
        self.stopAndRemoveCaptureSession()
        self._stopFollowingDeviceOrientation()
    }

    /**
    Inits a capture session and adds a preview layer to the given view. Preview layer bounds will automaticaly be set to match given view. Default session is initialized with still image output.

    :param: view The view you want to add the preview layer to
    :param: cameraOutputMode The mode you want capturesession to run image / video / video and microphone
    */
    func addPreviewLayerToView(view: UIView)
    {
        self.addPreviewLayerToView(view, newCameraOutputMode: _cameraOutputMode)
    }
    func addPreviewLayerToView(view: UIView, newCameraOutputMode: CameraOutputMode)
    {
        if let validEmbedingView = self.embedingView? {
            if let validPreviewLayer = self.previewLayer? {
                validPreviewLayer.removeFromSuperlayer()
            }
        }
        if self.cameraIsSetup {
            self._addPreeviewLayerToView(view)
            self.cameraOutputMode = newCameraOutputMode
        } else {
            self._setupCamera({ Void -> Void in
                self._addPreeviewLayerToView(view)
                self.cameraOutputMode = newCameraOutputMode
            })
        }
    }

    /**
    Stops running capture session but all setup devices, inputs and outputs stay for further reuse.
    */
    func stopCaptureSession()
    {
        self.captureSession?.stopRunning()
        self._stopFollowingDeviceOrientation()
    }

    /**
    Resumes capture session.
    */
    func resumeCaptureSession()
    {
        if let validCaptureSession = self.captureSession? {
            if !validCaptureSession.running && self.cameraIsSetup {
                validCaptureSession.startRunning()
                self._startFollowingDeviceOrientation()
            }
        } else {
            if self.cameraIsSetup {
                self.stopAndRemoveCaptureSession()
            }
            self._setupCamera({Void -> Void in
                if let validEmbedingView = self.embedingView? {
                    self._addPreeviewLayerToView(validEmbedingView)
                }
                self._startFollowingDeviceOrientation()
            })
        }
    }

    /**
    Stops running capture session and removes all setup devices, inputs and outputs.
    */
    func stopAndRemoveCaptureSession()
    {
        self.stopCaptureSession()
        self.cameraDevice = .Back
        self.cameraIsSetup = false
        self.previewLayer = nil
        self.captureSession = nil
        self.frontCamera = nil
        self.rearCamera = nil
        self.mic = nil
        self.stillImageOutput = nil
        self.movieOutput = nil
    }

    /**
    Captures still image from currently running capture session.

    :param: imageCompletition Completition block containing the captured UIImage
    */
    func capturePictureWithCompletition(imageCompletition: UIImage -> Void)
    {
        if self.cameraIsSetup {
            if self.cameraOutputMode == .StillImage {
                dispatch_async(self.sessionQueue, {
                    self._getStillImageOutput().captureStillImageAsynchronouslyFromConnection(self._getStillImageOutput().connectionWithMediaType(AVMediaTypeVideo), completionHandler: { [weak self] (sample: CMSampleBuffer!, error: NSError!) -> Void in
                        if (error? != nil) {
                            dispatch_async(dispatch_get_main_queue(), {
                                if let weakSelf = self {
                                    weakSelf._show("error", message: error.localizedDescription)
                                }
                            })
                        } else {
                            let imageData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(sample)
                            if let weakSelf = self {
                                if weakSelf.writeFilesToPhoneLibrary {
                                    if let validLibrary = weakSelf.library? {
                                        validLibrary.writeImageDataToSavedPhotosAlbum(imageData, metadata:nil, completionBlock: {
                                            (picUrl, error) -> Void in
                                            if (error? != nil) {
                                                dispatch_async(dispatch_get_main_queue(), {
                                                    weakSelf._show("error", message: error.localizedDescription)
                                                })
                                            }
                                        })
                                    }
                                }
                            }
                            imageCompletition(UIImage(data: imageData)!)
                        }
                    })
                })
            } else {
                self._show("Capture session output mode video", message: "I can't take any picture")
            }
        } else {
            self._show("No capture session setup", message: "I can't take any picture")
        }
    }

    /**
    Starts recording a video with or without voice as in the session preset.
    */
    func startRecordingVideo()
    {
        if self.cameraOutputMode != .StillImage {
            self._getMovieOutput().startRecordingToOutputFileURL(self.tempFilePath, recordingDelegate: self)
        } else {
            self._show("Capture session output still image", message: "I can only take pictures")
        }
    }

    /**
    Stop recording a video. Save it to the cameraRoll and give back the url.
    */
    func stopRecordingVideo(completition:(videoURL: NSURL) -> Void)
    {
        if let runningMovieOutput = self.movieOutput {
            if runningMovieOutput.recording {
                self.videoCompletition = completition
                runningMovieOutput.stopRecording()
            }
        }
    }


    // PRAGMA MARK - AVCaptureFileOutputRecordingDelegate

    func captureOutput(captureOutput: AVCaptureFileOutput!, didStartRecordingToOutputFileAtURL fileURL: NSURL!, fromConnections connections: [AnyObject]!)
    {

    }

    func captureOutput(captureOutput: AVCaptureFileOutput!, didFinishRecordingToOutputFileAtURL outputFileURL: NSURL!, fromConnections connections: [AnyObject]!, error: NSError!)
    {
        if (error != nil) {
            self._show("Unable to save video to the iPhone", message: error.localizedDescription)
        } else {
            if let validLibrary = self.library? {
                if self.writeFilesToPhoneLibrary {
                    validLibrary.writeVideoAtPathToSavedPhotosAlbum(outputFileURL, completionBlock: { (assetURL: NSURL?, error: NSError?) -> Void in
                        if (error != nil) {
                            self._show("Unable to save video to the iPhone.", message: error!.localizedDescription)
                        } else {
                            if let validAssetURL = assetURL {
                                self._executeVideoCompletitionWithURL(validAssetURL)
                            }
                        }
                    })
                } else {
                    self._executeVideoCompletitionWithURL(outputFileURL)
                }
            }
        }
    }

    // PRAGMA MARK - CameraManager()

    private func _executeVideoCompletitionWithURL(url: NSURL)
    {
        if let validCompletition = self.videoCompletition {
            validCompletition(videoURL: url)
            self.videoCompletition = nil
        }
    }

    private func _getMovieOutput() -> AVCaptureMovieFileOutput
    {
        var shouldReinitializeMovieOutput = self.movieOutput == nil
        if !shouldReinitializeMovieOutput {
            if let connection = self.movieOutput!.connectionWithMediaType(AVMediaTypeVideo) {
                shouldReinitializeMovieOutput = shouldReinitializeMovieOutput || !connection.active
            }
        }
        
        if shouldReinitializeMovieOutput {
            self.movieOutput = AVCaptureMovieFileOutput()
            
            self.captureSession?.beginConfiguration()
            self.captureSession?.addOutput(self.movieOutput)
            self.captureSession?.commitConfiguration()
        }
        return self.movieOutput!
    }
    
    private func _getStillImageOutput() -> AVCaptureStillImageOutput
    {
        var shouldReinitializeStillImageOutput = self.stillImageOutput == nil
        if !shouldReinitializeStillImageOutput {
            if let connection = self.stillImageOutput!.connectionWithMediaType(AVMediaTypeVideo) {
                shouldReinitializeStillImageOutput = shouldReinitializeStillImageOutput || !connection.active
            }
        }
        if shouldReinitializeStillImageOutput {
            self.stillImageOutput = AVCaptureStillImageOutput()
            
            self.captureSession?.beginConfiguration()
            self.captureSession?.addOutput(self.stillImageOutput)
            self.captureSession?.commitConfiguration()
        }
        return self.stillImageOutput!
    }
    
    @objc private func _orientationChanged()
    {
        var currentConnection: AVCaptureConnection?;
        switch self.cameraOutputMode {
        case .StillImage:
            currentConnection = self.stillImageOutput?.connectionWithMediaType(AVMediaTypeVideo)
        case .VideoOnly, .VideoWithMic:
            currentConnection = self._getMovieOutput().connectionWithMediaType(AVMediaTypeVideo)
        }
        if let validPreviewLayer = self.previewLayer? {
            if let validPreviewLayerConnection = validPreviewLayer.connection? {
                if validPreviewLayerConnection.supportsVideoOrientation {
                    validPreviewLayerConnection.videoOrientation = self._currentVideoOrientation()
                }
            }
            if let validOutputLayerConnection = currentConnection? {
                if validOutputLayerConnection.supportsVideoOrientation {
                    validOutputLayerConnection.videoOrientation = self._currentVideoOrientation()
                }
            }
            dispatch_async(dispatch_get_main_queue(), { () -> Void in
                if let validEmbedingView = self.embedingView? {
                    validPreviewLayer.frame = validEmbedingView.bounds
                }
            })
        }
    }

    private func _currentVideoOrientation() -> AVCaptureVideoOrientation
    {
        switch UIDevice.currentDevice().orientation {
        case .LandscapeLeft:
            return .LandscapeRight
        case .LandscapeRight:
            return .LandscapeLeft
        default:
            return .Portrait
        }
    }

    private func _setupCamera(completition: Void -> Void)
    {
        if self._checkIfCameraIsAvailable() {
            self.captureSession = AVCaptureSession()

            dispatch_async(sessionQueue, {
                if let validCaptureSession = self.captureSession? {
                    validCaptureSession.beginConfiguration()
                    validCaptureSession.sessionPreset = AVCaptureSessionPresetHigh
                    self._addVideoInput()
                    self._setupOutputs()
                    self._setupOutputMode(self._cameraOutputMode)
                    self.cameraOutputQuality = self._cameraOutputQuality
                    self._setupPreviewLayer()
                    validCaptureSession.commitConfiguration()
                    validCaptureSession.startRunning()
                    self._startFollowingDeviceOrientation()
                    self.cameraIsSetup = true
                    self._orientationChanged()

                    completition()
                }
            })
        } else {
           self._show("Camera unavailable", message: "The device does not have a camera")
        }
    }

    private func _startFollowingDeviceOrientation()
    {
        if !self.cameraIsObservingDeviceOrientation {
            NSNotificationCenter.defaultCenter().addObserver(self, selector: "_orientationChanged", name: UIDeviceOrientationDidChangeNotification, object: nil)
            self.cameraIsObservingDeviceOrientation = true
        }
    }

    private func _stopFollowingDeviceOrientation()
    {
        if self.cameraIsObservingDeviceOrientation {
            NSNotificationCenter.defaultCenter().removeObserver(self, name: UIDeviceOrientationDidChangeNotification, object: nil)
            self.cameraIsObservingDeviceOrientation = false
        }
    }

    private func _addPreeviewLayerToView(view: UIView)
    {
        self.embedingView = view
        dispatch_async(dispatch_get_main_queue(), { () -> Void in
            self.previewLayer?.frame = view.layer.bounds
            view.clipsToBounds = true
            view.layer.addSublayer(self.previewLayer)
        })
    }

    private func _checkIfCameraIsAvailable() -> Bool
    {
        let deviceHasCamera = UIImagePickerController.isCameraDeviceAvailable(UIImagePickerControllerCameraDevice.Rear) || UIImagePickerController.isCameraDeviceAvailable(UIImagePickerControllerCameraDevice.Front)
        return deviceHasCamera
    }

    private func _addVideoInput()
    {
        var error: NSError?

        if (self.frontCamera? == nil) || (self.rearCamera? == nil) {
            var videoFrontDevice: AVCaptureDevice?
            var videoBackDevice: AVCaptureDevice?
            for device: AnyObject in AVCaptureDevice.devicesWithMediaType(AVMediaTypeVideo) {
                if device.position == AVCaptureDevicePosition.Back {
                    videoBackDevice = device as? AVCaptureDevice
                } else if device.position == AVCaptureDevicePosition.Front {
                    videoFrontDevice = device as? AVCaptureDevice
                }
            }
            if (self.frontCamera? == nil) {
                if let validVideoFrontDevice = videoFrontDevice? {
                    self.frontCamera = AVCaptureDeviceInput.deviceInputWithDevice(validVideoFrontDevice, error: &error) as AVCaptureDeviceInput
                }
            }
            if (self.rearCamera? == nil) {
                if let validVideoBackDevice = videoBackDevice? {
                    self.rearCamera = AVCaptureDeviceInput.deviceInputWithDevice(validVideoBackDevice, error: &error) as AVCaptureDeviceInput
                }
            }
            if let validError = error? {
                self._show("Device setup error occured", message: validError.localizedDescription)
            }
        }
        self.cameraDevice = _cameraDevice
    }

    private func _setupMic()
    {
        if (self.mic == nil) {
            var error: NSError?
            let micDevice:AVCaptureDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeAudio);
            self.mic = AVCaptureDeviceInput.deviceInputWithDevice(micDevice, error: &error) as? AVCaptureDeviceInput;
            if let errorHappened = error? {
                self.mic = nil
                self._show("Mic error", message: errorHappened.description)
            }
        }
    }
    
    private func _setupOutputMode(newCameraOutputMode: CameraOutputMode)
    {
        self.captureSession?.beginConfiguration()
        
        if (_cameraOutputMode != newCameraOutputMode) {
            // remove current setting
            switch _cameraOutputMode {
            case .StillImage:
                if let validStillImageOutput = self.stillImageOutput? {
                    self.captureSession?.removeOutput(validStillImageOutput)
                }
            case .VideoOnly, .VideoWithMic:
                if let validMovieOutput = self.movieOutput? {
                    self.captureSession?.removeOutput(validMovieOutput)
                }
                if _cameraOutputMode == .VideoWithMic {
                    if let validMic = self.mic? {
                        self.captureSession?.removeInput(validMic)
                    }
                }
            }
        }
        
        // configure new devices
        switch newCameraOutputMode {
        case .StillImage:
            if (self.stillImageOutput == nil) {
                self._setupOutputs()
            }
            if let validStillImageOutput = self.stillImageOutput? {
                self.captureSession?.addOutput(validStillImageOutput)
            }
        case .VideoOnly, .VideoWithMic:
            self.captureSession?.addOutput(self._getMovieOutput())
            
            if newCameraOutputMode == .VideoWithMic {
                if (self.mic == nil) {
                    self._setupMic()
                }
                if let validMic = self.mic? {
                    self.captureSession?.addInput(validMic)
                }
            }
        }
        self.captureSession?.commitConfiguration()
        _cameraOutputMode = newCameraOutputMode;
        self._orientationChanged()
    }
    
    private func _setupOutputs()
    {
        if (self.stillImageOutput == nil) {
            self.stillImageOutput = AVCaptureStillImageOutput()
        }
        if (self.movieOutput == nil) {
            self.movieOutput = AVCaptureMovieFileOutput()
        }
        if self.library == nil {
            self.library = ALAssetsLibrary()
        }
    }

    private func _setupPreviewLayer()
    {
        if let validCaptureSession = self.captureSession? {
            self.previewLayer = AVCaptureVideoPreviewLayer(session: validCaptureSession)
            self.previewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
        }
    }

    private func _show(title: String, message: String)
    {
        if self.showErrorsToUsers {
            dispatch_async(dispatch_get_main_queue(), { () -> Void in
                self.showErrorBlock(erTitle: title, erMessage: message)
            })
        }
    }
}