space-ios/iOSClient/Viewer/NCViewerImage/NCViewerImagePageContainer.swift

//
//  NCViewerImagePageContainer.swift
//  Nextcloud
//
//  Created by Marino Faggiana on 24/10/2020.
//  Copyright © 2020 Marino Faggiana. All rights reserved.
//
//  Author Marino Faggiana <marino.faggiana@nextcloud.com>
//
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU General Public License for more details.
//
//  You should have received a copy of the GNU General Public License
//  along with this program.  If not, see <http://www.gnu.org/licenses/>.
//

import UIKit
import SVGKit

class NCViewerImagePageContainer: UIViewController, UIGestureRecognizerDelegate {

    enum ScreenMode {
        case full, normal
    }
    var currentMode: ScreenMode = .normal
        
    var pageViewController: UIPageViewController {
        return self.children[0] as! UIPageViewController
    }
    
    var currentViewController: NCViewerImageZoom {
        return self.pageViewController.viewControllers![0] as! NCViewerImageZoom
    }
    
    var metadatas: [tableMetadata] = []
    var metadata: tableMetadata = tableMetadata()
    var currentIndex = 0
    var nextIndex: Int?
   
    var startPanLocation = CGPoint.zero
    let panDistanceForPopViewController: CGFloat = 100
    var defaultImageViewTopConstraint: CGFloat = 0
    var defaultImageViewBottomConstraint: CGFloat = 0
    
    var panGestureRecognizer: UIPanGestureRecognizer!
    var singleTapGestureRecognizer: UITapGestureRecognizer!
        
    override func viewDidLoad() {
        super.viewDidLoad()
        
        singleTapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(didSingleTapWith(gestureRecognizer:)))
        panGestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(didPanWith(gestureRecognizer:)))

        pageViewController.delegate = self
        pageViewController.dataSource = self
        pageViewController.view.addGestureRecognizer(self.panGestureRecognizer)
        pageViewController.view.addGestureRecognizer(self.singleTapGestureRecognizer)
        
        metadata = metadatas[currentIndex]

        let viewerImageZoom = UIStoryboard(name: "NCViewerImage", bundle: nil).instantiateViewController(withIdentifier: "NCViewerImageZoom") as! NCViewerImageZoom
        
        viewerImageZoom.index = currentIndex
        viewerImageZoom.image = getImageMetadata(metadata)
        viewerImageZoom.metadata = metadata
        viewerImageZoom.delegate = self

        singleTapGestureRecognizer.require(toFail: viewerImageZoom.doubleTapGestureRecognizer)
        
        pageViewController.setViewControllers([viewerImageZoom], direction: .forward, animated: true, completion: nil)
        
        NotificationCenter.default.addObserver(self, selector: #selector(changeTheming), name: NSNotification.Name(rawValue: k_notificationCenter_changeTheming), object: nil)
        
        /*
        NotificationCenter.default.addObserver(self, selector: #selector(downloadedFile(_:)), name: NSNotification.Name(rawValue: k_notificationCenter_downloadedFile), object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(uploadedFile(_:)), name: NSNotification.Name(rawValue: k_notificationCenter_uploadedFile), object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(deleteFile(_:)), name: NSNotification.Name(rawValue: k_notificationCenter_deleteFile), object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(renameFile(_:)), name: NSNotification.Name(rawValue: k_notificationCenter_renameFile), object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(moveFile(_:)), name: NSNotification.Name(rawValue: k_notificationCenter_moveFile), object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(triggerProgressTask(_:)), name: NSNotification.Name(rawValue: k_notificationCenter_progressTask), object:nil)
               
        NotificationCenter.default.addObserver(self, selector: #selector(downloadImage(_:)), name: NSNotification.Name(rawValue: k_notificationCenter_menuDownloadImage), object: nil)
        NotificationCenter.default.addObserver(self, selector: #selector(saveLivePhoto(_:)), name: NSNotification.Name(rawValue: k_notificationCenter_menuSaveLivePhoto), object: nil)
        */
        NotificationCenter.default.addObserver(self, selector: #selector(viewUnload), name: NSNotification.Name(rawValue: k_notificationCenter_menuDetailClose), object: nil)
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        let buttonMore = UIBarButtonItem.init(image: CCGraphics.changeThemingColorImage(UIImage(named: "more"), width: 50, height: 50, color: NCBrandColor.sharedInstance.textView), style: .plain, target: self, action: #selector(self.openMenuMore))
        navigationItem.rightBarButtonItem = buttonMore
        
        navigationController?.setNavigationBarHidden(false, animated: true)
        navigationController?.navigationBar.prefersLargeTitles = true
    }
    
    @objc func viewUnload() {
        
        navigationController?.popViewController(animated: true)
    }
    
    //MARK: - NotificationCenter

    @objc func changeTheming() {
        if currentMode == .normal {
            view.backgroundColor = NCBrandColor.sharedInstance.backgroundView
        }
    }
    
    //MARK: - Gesture

    func gestureRecognizerShouldBegin(_ gestureRecognizer: UIGestureRecognizer) -> Bool {
        
        if let gestureRecognizer = gestureRecognizer as? UIPanGestureRecognizer {
            let velocity = gestureRecognizer.velocity(in: self.view)
            
            var velocityCheck : Bool = false
            
            if UIDevice.current.orientation.isLandscape {
                velocityCheck = velocity.x < 0
            }
            else {
                velocityCheck = velocity.y < 0
            }
            if velocityCheck {
                return false
            }
        }
        
        return true
    }
    
    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldRecognizeSimultaneouslyWith otherGestureRecognizer: UIGestureRecognizer) -> Bool {
        
        if otherGestureRecognizer == currentViewController.scrollView.panGestureRecognizer {
            if self.currentViewController.scrollView.contentOffset.y == 0 {
                return true
            }
        }
        
        return false
    }

    @objc func didPanWith(gestureRecognizer: UIPanGestureRecognizer) {
        let currentLocation = gestureRecognizer.translation(in: self.view)

        switch gestureRecognizer.state {
        case .began:
            startPanLocation = currentLocation
            defaultImageViewTopConstraint = currentViewController.imageViewTopConstraint.constant
            defaultImageViewBottomConstraint = currentViewController.imageViewBottomConstraint.constant
            currentViewController.scrollView.isScrollEnabled = false
        case .ended:
            currentViewController.scrollView.isScrollEnabled = true
            currentViewController.imageViewTopConstraint.constant = defaultImageViewTopConstraint
            currentViewController.imageViewBottomConstraint.constant = defaultImageViewBottomConstraint
        case .changed:
            let dy = currentLocation.y - startPanLocation.y
            currentViewController.imageViewTopConstraint.constant = defaultImageViewTopConstraint + dy
            currentViewController.imageViewBottomConstraint.constant = defaultImageViewBottomConstraint - dy
            if dy >= panDistanceForPopViewController {
                self.navigationController?.popViewController(animated: true)
            }
            print(dy)
        default:
            break
        }
    }
    
    @objc func didSingleTapWith(gestureRecognizer: UITapGestureRecognizer) {
        if currentMode == .full {
            changeScreenMode(to: .normal)
            currentMode = .normal
        } else {
            changeScreenMode(to: .full)
            currentMode = .full
        }
    }
    
    //MARK: - Function

    func changeScreenMode(to: ScreenMode) {
        if to == .full {
            navigationController?.setNavigationBarHidden(true, animated: false)
            view.backgroundColor = .black
        } else {
            navigationController?.setNavigationBarHidden(false, animated: false)
            view.backgroundColor = NCBrandColor.sharedInstance.backgroundView
        }
    }
    
    func getImageMetadata(_ metadata: tableMetadata) -> UIImage? {
                
        if let image = getImage(metadata: metadata) {
            return image
        }
        
        if CCUtility.fileProviderStoragePreviewIconExists(metadata.ocId, etag: metadata.etag) {
            if let imagePath = CCUtility.getDirectoryProviderStoragePreviewOcId(metadata.ocId, etag: metadata.etag) {
                return UIImage.init(contentsOfFile: imagePath)
            } 
        }
        
        return NCCollectionCommon.images.cellFileImage
    }
    
    private func getImage(metadata: tableMetadata) -> UIImage? {
        
        let ext = CCUtility.getExtension(metadata.fileNameView)
        var image: UIImage?
        
        if CCUtility.fileProviderStorageSize(metadata.ocId, fileNameView: metadata.fileNameView) > 0 && metadata.typeFile == k_metadataTypeFile_image {
           
            let previewPath = CCUtility.getDirectoryProviderStoragePreviewOcId(metadata.ocId, etag: metadata.etag)!
            let imagePath = CCUtility.getDirectoryProviderStorageOcId(metadata.ocId, fileNameView: metadata.fileNameView)!
            
            if ext == "GIF" {
                if !FileManager().fileExists(atPath: previewPath) {
                    CCGraphics.createNewImage(from: metadata.fileNameView, ocId: metadata.ocId, etag: metadata.etag, typeFile: metadata.typeFile)
                }
                image = UIImage.animatedImage(withAnimatedGIFURL: URL(fileURLWithPath: imagePath))
            } else if ext == "SVG" {
                if let svgImage = SVGKImage(contentsOfFile: imagePath) {
                    let scale = svgImage.size.height / svgImage.size.width
                    svgImage.size = CGSize(width: CGFloat(k_sizePreview), height: (CGFloat(k_sizePreview) * scale))
                    if let image = svgImage.uiImage {
                        if !FileManager().fileExists(atPath: previewPath) {
                            do {
                                try image.pngData()?.write(to: URL(fileURLWithPath: previewPath), options: .atomic)
                            } catch { }
                        }
                        return image
                    } else {
                        return nil
                    }
                } else {
                    return nil
                }
            } else {
                if !FileManager().fileExists(atPath: previewPath) {
                    CCGraphics.createNewImage(from: metadata.fileNameView, ocId: metadata.ocId, etag: metadata.etag, typeFile: metadata.typeFile)
                }
                image = UIImage.init(contentsOfFile: imagePath)
            }
            
        } else {
            
            // AUTOMATIC DOWNLOAD FOR GIF
            
            if (ext == "GIF" || ext == "SVG") && metadata.session == "" {
                NotificationCenter.default.postOnMainThread(name: k_notificationCenter_menuDownloadImage, userInfo: ["metadata": metadata])
            }
        }
        
        return image
    }
    
    //MARK: - Action
    
    @objc func openMenuMore() {
        NCViewer.shared.toggleMoreMenu(viewController: self, metadata: metadata)
    }
}

extension NCViewerImagePageContainer: UIPageViewControllerDelegate, UIPageViewControllerDataSource {
    
    func pageViewController(_ pageViewController: UIPageViewController, viewControllerBefore viewController: UIViewController) -> UIViewController? {
        if currentIndex == 0 { return nil }
        
        metadata = metadatas[currentIndex - 1]

        let viewerImageZoom = UIStoryboard(name: "NCViewerImage", bundle: nil).instantiateViewController(withIdentifier: "NCViewerImageZoom") as! NCViewerImageZoom
                
        viewerImageZoom.image = getImageMetadata(metadata)
        viewerImageZoom.index = currentIndex - 1
        viewerImageZoom.metadata = metadata
        viewerImageZoom.delegate = self
        
        self.singleTapGestureRecognizer.require(toFail: viewerImageZoom.doubleTapGestureRecognizer)
        
        return viewerImageZoom
    }
    
    func pageViewController(_ pageViewController: UIPageViewController, viewControllerAfter viewController: UIViewController) -> UIViewController? {
        if currentIndex == (self.metadatas.count - 1) { return nil }
        
        metadata = metadatas[currentIndex + 1]
        
        let viewerImageZoom = UIStoryboard(name: "NCViewerImage", bundle: nil).instantiateViewController(withIdentifier: "NCViewerImageZoom") as! NCViewerImageZoom
        
        viewerImageZoom.index = currentIndex + 1
        viewerImageZoom.image = getImageMetadata(metadata)
        viewerImageZoom.metadata = metadata
        viewerImageZoom.delegate = self
        
        singleTapGestureRecognizer.require(toFail: viewerImageZoom.doubleTapGestureRecognizer)

        return viewerImageZoom
    }
    
    func pageViewController(_ pageViewController: UIPageViewController, willTransitionTo pendingViewControllers: [UIViewController]) {
        
        guard let nextVC = pendingViewControllers.first as? NCViewerImageZoom else {
            return
        }
        
        self.nextIndex = nextVC.index
    }
    
    func pageViewController(_ pageViewController: UIPageViewController, didFinishAnimating finished: Bool, previousViewControllers: [UIViewController], transitionCompleted completed: Bool) {
        
        if (completed && self.nextIndex != nil) {
            previousViewControllers.forEach { vc in
                let viewerImageZoom = vc as! NCViewerImageZoom
                viewerImageZoom.scrollView.zoomScale = viewerImageZoom.scrollView.minimumZoomScale
            }

            currentIndex = nextIndex!
        }
        
        self.nextIndex = nil
    }
}