import UIKit
import Social
import MobileCoreServices
import Photos

class ShareViewController: SLComposeServiceViewController {
    var hostAppBundleIdentifier = "com.jgeek00.linkdy"
    var appGroupId = "group.com.jgeek00.linkdy"
    let sharedKey = "ShareKey"
    var sharedMedia: [SharedMediaFile] = []
    var sharedText: [String] = []
    let imageContentType = kUTTypeImage as String
    let videoContentType = kUTTypeMovie as String
    let textContentType = kUTTypeText as String
    let urlContentType = kUTTypeURL as String
    let fileURLType = kUTTypeFileURL as String
    
    override func isContentValid() -> Bool {
        return true
    }
    
    private func loadIds() {
        // loading Share extension App Id
        let shareExtensionAppBundleIdentifier = Bundle.main.bundleIdentifier!
        
        // convert ShareExtension id to host app id
        // By default it is removed the last part of id after the last point
        // For example: com.test.ShareExtension -> com.test
        if let lastIndexOfPoint = shareExtensionAppBundleIdentifier.lastIndex(of: ".") {
            hostAppBundleIdentifier = String(shareExtensionAppBundleIdentifier[..<lastIndexOfPoint])
        }
        
        // loading custom AppGroupId from Build Settings or use group.<hostAppBundleIdentifier>
        appGroupId = (Bundle.main.object(forInfoDictionaryKey: "AppGroupId") as? String) ?? "group.\(hostAppBundleIdentifier)"
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // load group and app id from build info
        loadIds()
    }
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        
        // This is called after the user selects Post. Do the upload of contentText and/or NSExtensionContext attachments.
        if let content = extensionContext?.inputItems[0] as? NSExtensionItem {
            if let contents = content.attachments {
                for (index, attachment) in contents.enumerated() {
                    if attachment.hasItemConformingToTypeIdentifier(imageContentType) {
                        handleImages(content: content, attachment: attachment, index: index)
                    } else if attachment.hasItemConformingToTypeIdentifier(textContentType) {
                        handleText(content: content, attachment: attachment, index: index)
                    } else if attachment.hasItemConformingToTypeIdentifier(fileURLType) {
                        handleFiles(content: content, attachment: attachment, index: index)
                    } else if attachment.hasItemConformingToTypeIdentifier(urlContentType) {
                        handleUrl(content: content, attachment: attachment, index: index)
                    } else if attachment.hasItemConformingToTypeIdentifier(videoContentType) {
                        handleVideos(content: content, attachment: attachment, index: index)
                    }
                }
            }
        }
    }
    
    override func didSelectPost() {
        print("didSelectPost")
    }
    
    override func configurationItems() -> [Any]! {
        // To add configuration options via table cells at the bottom of the sheet, return an array of SLComposeSheetConfigurationItem here.
        return []
    }
    
    private func handleText(content: NSExtensionItem, attachment: NSItemProvider, index: Int) {
        attachment.loadItem(forTypeIdentifier: textContentType, options: nil) { [weak self] data, error in
            
            if error == nil, let item = data as? String, let this = self {
                
                this.sharedText.append(item)
                
                // If this is the last item, save imagesData in userDefaults and redirect to the host app
                if index == (content.attachments?.count)! - 1 {
                    let userDefaults = UserDefaults(suiteName: this.appGroupId)
                    userDefaults?.set(this.sharedText, forKey: this.sharedKey)
                    userDefaults?.synchronize()
                    this.redirectToHostApp(type: .text)
                }
                
            } else {
                self?.dismissWithError()
            }
        }
    }
    
    private func handleUrl(content: NSExtensionItem, attachment: NSItemProvider, index: Int) {
        attachment.loadItem(forTypeIdentifier: urlContentType, options: nil) { [weak self] data, error in
            
            if error == nil, let item = data as? URL, let this = self {
                
                this.sharedText.append(item.absoluteString)
                
                // If this is the last item, save imagesData in userDefaults and redirect to the host app
                if index == (content.attachments?.count)! - 1 {
                    let userDefaults = UserDefaults(suiteName: this.appGroupId)
                    userDefaults?.set(this.sharedText, forKey: this.sharedKey)
                    userDefaults?.synchronize()
                    this.redirectToHostApp(type: .text)
                }
                
            } else {
                self?.dismissWithError()
            }
        }
    }
    
    private func handleImages(content: NSExtensionItem, attachment: NSItemProvider, index: Int) {
        attachment.loadItem(forTypeIdentifier: imageContentType, options: nil) { [weak self] data, error in
            
            if error == nil, let url = data as? URL, let this = self {
                
                // Always copy
                let fileName = this.getFileName(from: url, type: .image)
                let newPath = FileManager.default
                    .containerURL(forSecurityApplicationGroupIdentifier: this.appGroupId)!
                    .appendingPathComponent(fileName)
                let copied = this.copyFile(at: url, to: newPath)
                if copied {
                    this.sharedMedia.append(SharedMediaFile(path: newPath.absoluteString, thumbnail: nil, duration: nil, type: .image))
                }
                
                // If this is the last item, save imagesData in userDefaults and redirect to the host app
                if index == (content.attachments?.count)! - 1 {
                    let userDefaults = UserDefaults(suiteName: this.appGroupId)
                    userDefaults?.set(this.toData(data: this.sharedMedia), forKey: this.sharedKey)
                    userDefaults?.synchronize()
                    this.redirectToHostApp(type: .media)
                }
                
            } else {
                self?.dismissWithError()
            }
        }
    }
    
    private func handleVideos(content: NSExtensionItem, attachment: NSItemProvider, index: Int) {
        attachment.loadItem(forTypeIdentifier: videoContentType, options: nil) { [weak self] data, error in
            
            if error == nil, let url = data as? URL, let this = self {
                
                // Always copy
                let fileName = this.getFileName(from: url, type: .video)
                let newPath = FileManager.default
                    .containerURL(forSecurityApplicationGroupIdentifier: this.appGroupId)!
                    .appendingPathComponent(fileName)
                let copied = this.copyFile(at: url, to: newPath)
                if copied {
                    guard let sharedFile = this.getSharedMediaFile(forVideo: newPath) else {
                        return
                    }
                    this.sharedMedia.append(sharedFile)
                }
                
                // If this is the last item, save imagesData in userDefaults and redirect to the host app
                if index == (content.attachments?.count)! - 1 {
                    let userDefaults = UserDefaults(suiteName: this.appGroupId)
                    userDefaults?.set(this.toData(data: this.sharedMedia), forKey: this.sharedKey)
                    userDefaults?.synchronize()
                    this.redirectToHostApp(type: .media)
                }
                
            } else {
                self?.dismissWithError()
            }
        }
    }
    
    private func handleFiles(content: NSExtensionItem, attachment: NSItemProvider, index: Int) {
        attachment.loadItem(forTypeIdentifier: fileURLType, options: nil) { [weak self] data, error in
            
            if error == nil, let url = data as? URL, let this = self {
                
                // Always copy
                let fileName = this.getFileName(from: url, type: .file)
                let newPath = FileManager.default
                    .containerURL(forSecurityApplicationGroupIdentifier: this.appGroupId)!
                    .appendingPathComponent(fileName)
                let copied = this.copyFile(at: url, to: newPath)
                if copied {
                    this.sharedMedia.append(SharedMediaFile(path: newPath.absoluteString, thumbnail: nil, duration: nil, type: .file))
                }
                
                if index == (content.attachments?.count)! - 1 {
                    let userDefaults = UserDefaults(suiteName: this.appGroupId)
                    userDefaults?.set(this.toData(data: this.sharedMedia), forKey: this.sharedKey)
                    userDefaults?.synchronize()
                    this.redirectToHostApp(type: .file)
                }
                
            } else {
                self?.dismissWithError()
            }
        }
    }
    
    private func dismissWithError() {
        print("[ERROR] Error loading data!")
        let alert = UIAlertController(title: "Error", message: "Error loading data", preferredStyle: .alert)
        
        let action = UIAlertAction(title: "Error", style: .cancel) { _ in
            self.dismiss(animated: true, completion: nil)
        }
        
        alert.addAction(action)
        present(alert, animated: true, completion: nil)
        extensionContext?.completeRequest(returningItems: [], completionHandler: nil)
    }
    
    private func redirectToHostApp(type: RedirectType) {
        // ids may not be loaded yet so we need loadIds here too
        loadIds()
        let url = URL(string: "ShareMedia-\(hostAppBundleIdentifier)://dataUrl=\(sharedKey)#\(type)")
        var responder = self as UIResponder?
        let selectorOpenURL = sel_registerName("openURL:")
        
        while (responder != nil) {
            if (responder?.responds(to: selectorOpenURL))! {
                let _ = responder?.perform(selectorOpenURL, with: url)
            }
            responder = responder?.next
        }
        extensionContext?.completeRequest(returningItems: [], completionHandler: nil)
    }
    
    enum RedirectType {
        case media
        case text
        case file
    }
    
    func getExtension(from url: URL, type: SharedMediaType) -> String {
        let parts = url.lastPathComponent.components(separatedBy: ".")
        var ex: String? = nil
        if (parts.count > 1) {
            ex = parts.last
        }
        
        if (ex == nil) {
            switch type {
                case .image:
                    ex = "PNG"
                case .video:
                    ex = "MP4"
                case .file:
                    ex = "TXT"
            }
        }
        return ex ?? "Unknown"
    }
    
    func getFileName(from url: URL, type: SharedMediaType) -> String {
        var name = url.lastPathComponent
        
        if (name.isEmpty) {
            name = UUID().uuidString + "." + getExtension(from: url, type: type)
        }
        
        return name
    }
    
    func copyFile(at srcURL: URL, to dstURL: URL) -> Bool {
        do {
            if FileManager.default.fileExists(atPath: dstURL.path) {
                try FileManager.default.removeItem(at: dstURL)
            }
            try FileManager.default.copyItem(at: srcURL, to: dstURL)
        } catch (let error) {
            print("Cannot copy item at \(srcURL) to \(dstURL): \(error)")
            return false
        }
        return true
    }
    
    private func getSharedMediaFile(forVideo: URL) -> SharedMediaFile? {
        let asset = AVAsset(url: forVideo)
        let duration = (CMTimeGetSeconds(asset.duration) * 1000).rounded()
        let thumbnailPath = getThumbnailPath(for: forVideo)
        
        if FileManager.default.fileExists(atPath: thumbnailPath.path) {
            return SharedMediaFile(path: forVideo.absoluteString, thumbnail: thumbnailPath.absoluteString, duration: duration, type: .video)
        }
        
        var saved = false
        let assetImgGenerate = AVAssetImageGenerator(asset: asset)
        assetImgGenerate.appliesPreferredTrackTransform = true
        assetImgGenerate.maximumSize =  CGSize(width: 360, height: 360)
        do {
            let img = try assetImgGenerate.copyCGImage(at: CMTimeMakeWithSeconds(600, preferredTimescale: Int32(1.0)), actualTime: nil)
            try UIImage.pngData(UIImage(cgImage: img))()?.write(to: thumbnailPath)
            saved = true
        } catch {
            saved = false
        }
        
        return saved ? SharedMediaFile(path: forVideo.absoluteString, thumbnail: thumbnailPath.absoluteString, duration: duration, type: .video) : nil
    }
    
    private func getThumbnailPath(for url: URL) -> URL {
        let fileName = Data(url.lastPathComponent.utf8).base64EncodedString().replacingOccurrences(of: "==", with: "")
        let path = FileManager.default
            .containerURL(forSecurityApplicationGroupIdentifier: appGroupId)!
            .appendingPathComponent("\(fileName).jpg")
        return path
    }
    
    class SharedMediaFile: Codable {
        var path: String
        var thumbnail: String?
        var duration: Double?
        var type: SharedMediaType
        
        init(path: String, thumbnail: String?, duration: Double?, type: SharedMediaType) {
            self.path = path
            self.thumbnail = thumbnail
            self.duration = duration
            self.type = type
        }
        
        func toString() {
            print("[SharedMediaFile] \n\tpath: \(self.path)\n\tthumbnail: \(self.thumbnail)\n\tduration: \(self.duration)\n\ttype: \(self.type)")
        }
    }
    
    enum SharedMediaType: Int, Codable {
        case image
        case video
        case file
    }
    
    func toData(data: [SharedMediaFile]) -> Data {
        let encodedData = try? JSONEncoder().encode(data)
        return encodedData ?? Data()
    }
}

extension Array {
    subscript (safe index: UInt) -> Element? {
        return Int(index) < count ? self[Int(index)] : nil
    }
}