//
//  ViewController.swift
//  PhotoCaptureSample
//
//  Created by Tadashi on 2017/09/23.
//  Copyright © 2017 UBUNIFU Incorporated. All rights reserved.
//
import UIKit
import AVFoundation
import Photos

class ViewController: UIViewController, AVCapturePhotoCaptureDelegate {

	var captureSession: AVCaptureSession?
	var capturePhotoOutput: AVCapturePhotoOutput?
	var previewLayer: AVCaptureVideoPreviewLayer?
	@objc var captureDevice: AVCaptureDevice?

	@IBOutlet weak var exposure: UILabel!
	@IBOutlet weak var iso: UILabel!
	@IBOutlet weak var lensPosition: UILabel!
	@IBOutlet var preView: UIView!

	@IBOutlet var capture: UIButton!
	@IBAction func capture(_ sender: Any) {
		let photoSettings : AVCapturePhotoSettings!
		photoSettings = AVCapturePhotoSettings.init(format: [AVVideoCodecKey: AVVideoCodecType.jpeg])
		photoSettings.isAutoStillImageStabilizationEnabled = true
		photoSettings.flashMode = .off
		photoSettings.isHighResolutionPhotoEnabled = false
		self.capturePhotoOutput?.capturePhoto(with: photoSettings, delegate: self)
	}

	override func viewDidLoad() {
		super.viewDidLoad()

		self.captureSession = AVCaptureSession()
		self.captureSession?.sessionPreset = .photo
		self.capturePhotoOutput = AVCapturePhotoOutput()
		self.captureDevice = AVCaptureDevice.default(for: .video)
		let input = try! AVCaptureDeviceInput(device: self.captureDevice!)
		self.captureSession?.addInput(input)
		self.captureSession?.addOutput(self.capturePhotoOutput!)

		self.previewLayer = AVCaptureVideoPreviewLayer(session: self.captureSession!)
		self.previewLayer?.frame = self.preView.bounds
		self.previewLayer?.videoGravity = AVLayerVideoGravity.resizeAspectFill
		self.previewLayer?.connection?.videoOrientation = AVCaptureVideoOrientation.portrait
		self.preView.layer.addSublayer(self.previewLayer!)

		self.captureSession?.startRunning()
	}
	
	override func viewWillAppear(_ animated: Bool) {
		super.viewWillAppear(animated)
		self.addObservers()
	}

	override func viewWillDisappear(_ animated: Bool) {
		super.viewWillDisappear(animated)
		self.removeObservers()
	}

	func photoOutput(_ output: AVCapturePhotoOutput, didFinishProcessingPhoto photo: AVCapturePhoto, error: Error?) {
		PHPhotoLibrary.shared().performChanges( {
			let creationRequest = PHAssetCreationRequest.forAsset()
			creationRequest.addResource(with: PHAssetResourceType.photo, data: photo.fileDataRepresentation()!, options: nil)
		}, completionHandler: nil)
	}

	func photoOutput(_ captureOutput: AVCapturePhotoOutput,
			didFinishCaptureFor resolvedSettings: AVCaptureResolvedPhotoSettings,
			error: Error?) {

		guard error == nil else {
			print("Error in capture process: \(String(describing: error))")
			return
		}
	}

	func addObservers() {
		self.addObserver(self, forKeyPath: "captureDevice.lensPosition" , options: .new, context: nil)
		self.addObserver(self, forKeyPath: "captureDevice.exposureDuration", options: .new, context: nil)
		self.addObserver(self, forKeyPath: "captureDevice.ISO", options: .new, context: nil)
	}

	func removeObservers() {
		self.removeObserver(self, forKeyPath: "captureDevice.lensPosition")
		self.removeObserver(self, forKeyPath: "captureDevice.exposureDuration")
		self.removeObserver(self, forKeyPath: "captureDevice.ISO")
	}

	override func observeValue(forKeyPath keyPath: String?,
		of object: Any?,
		change: [NSKeyValueChangeKey: Any]?,
		context: UnsafeMutableRawPointer?) {

		if keyPath == "captureDevice.lensPosition" {
			self.lensPosition.text = String(format: "%.1f", (self.captureDevice?.lensPosition)!)
		}

		if keyPath == "captureDevice.exposureDuration" {
			let exposureDurationSeconds = CMTimeGetSeconds( (self.captureDevice?.exposureDuration)! )
			self.exposure.text = String(format: "1/%.f", 1.0 / exposureDurationSeconds)
		}

		if keyPath == "captureDevice.ISO" {
			self.iso.text = String(format: "%.f", (self.captureDevice?.iso)!)
		}
    }

	override func didReceiveMemoryWarning() {
		super.didReceiveMemoryWarning()
	}
}