import UIKit
import MobileCoreServices
import UniformTypeIdentifiers

public class SharedMediaFile: Codable {
    var path: String
    var mimeType: String?
    var thumbnail: String? // video thumbnail
    var duration: Double? // video duration in milliseconds
    var message: String? // post message
    var type: SharedMediaType
    
    public init(
        path: String,
        mimeType: String? = nil,
        thumbnail: String? = nil,
        duration: Double? = nil,
        message: String?=nil,
        type: SharedMediaType) {
            self.path = path
            self.mimeType = mimeType
            self.thumbnail = thumbnail
            self.duration = duration
            self.message = message
            self.type = type
        }
}

public enum SharedMediaType: String, Codable, CaseIterable {
    case image
    case video
    case text
    case file
    case url

    public var toUTTypeIdentifier: String {
        if #available(iOS 14.0, *) {
            switch self {
            case .image:
                return UTType.image.identifier
            case .video:
                return UTType.movie.identifier
            case .text:
                return UTType.text.identifier
            case .file:
                return UTType.fileURL.identifier
            case .url:
                return UTType.url.identifier
            }
        }
        switch self {
        case .image:
            return "public.image"
        case .video:
            return "public.movie"
        case .text:
            return "public.text"
        case .file:
            return "public.file-url"
        case .url:
            return "public.url"
        }
    }
}

let kSchemePrefix = "ShareMedia"
let kUserDefaultsKey = "ShareKey"
let kUserDefaultsMessageKey = "ShareMessageKey"
let kAppGroupIdKey = "AppGroupId"

class ActionViewController: UIViewController {
    var hostAppBundleIdentifier = "com.jiaqi.hacki"
    var appGroupId = "group.com.jiaqi.hacki"
    var sharedText: [String] = []
    var sharedMedia: [SharedMediaFile] = []
    let urlContentType = UTType.url
    @IBOutlet weak var imageView: UIImageView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
    }
    
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        if let content = extensionContext!.inputItems[0] as? NSExtensionItem {
            if let contents = content.attachments {
                for (index, attachment) in (contents).enumerated() {
                    handleUrl(content: content, attachment: attachment, index: index)
                }
            }
        }
    }
    
    private func handleUrl (content: NSExtensionItem, attachment: NSItemProvider, index: Int) {
        attachment.loadItem(forTypeIdentifier: urlContentType.identifier, 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 host app
                if index == (content.attachments?.count)! - 1 {
                    this.sharedMedia.removeAll()
                    this.sharedMedia.append(.init(path: item.absoluteString, type: .url))
                    print(this.sharedText)
                    this.saveAndRedirect()
                }
            } 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)
    }
    
    // Save shared media and redirect to host app
    private func saveAndRedirect(message: String? = nil) {
        let userDefaults = UserDefaults(suiteName: appGroupId)
        userDefaults?.set(toData(data: sharedMedia), forKey: kUserDefaultsKey)
        userDefaults?.set(message, forKey: kUserDefaultsMessageKey)
        userDefaults?.synchronize()
        redirectToHostApp()
    }
    
    private func toData(data: [SharedMediaFile]) -> Data {
        let encodedData = try? JSONEncoder().encode(data)
        return encodedData!
    }
    
    private func redirectToHostApp() {
        // ids may not loaded yet so we need loadIds here too
        loadIds()
        let url = URL(string: "\(kSchemePrefix)-\(hostAppBundleIdentifier):share")
        var responder = self as UIResponder?
        
        if #available(iOS 18.0, *) {
            while responder != nil {
                if let application = responder as? UIApplication {
                    application.open(url!, options: [:], completionHandler: nil)
                }
                responder = responder?.next
            }
        } else {
            let selectorOpenURL = sel_registerName("openURL:")
            
            while (responder != nil) {
                if (responder?.responds(to: selectorOpenURL))! {
                    _ = responder?.perform(selectorOpenURL, with: url)
                }
                responder = responder!.next
            }
        }

        extensionContext!.completeRequest(returningItems: [], completionHandler: nil)
    }
    
    private func loadIds() {
        // loading Share extension App Id
        let shareExtensionAppBundleIdentifier = Bundle.main.bundleIdentifier!
        
        
        // extract host app bundle id from ShareExtension id
        // by default it's <hostAppBundleIdentifier>.<ShareExtension>
        // for example: "com.kasem.sharing.Share-Extension" -> com.kasem.sharing
        let lastIndexOfPoint = shareExtensionAppBundleIdentifier.lastIndex(of: ".")
        hostAppBundleIdentifier = String(shareExtensionAppBundleIdentifier[..<lastIndexOfPoint!])
        let defaultAppGroupId = "group.\(hostAppBundleIdentifier)"
        
        
        // loading custom AppGroupId from Build Settings or use group.<hostAppBundleIdentifier>
        let customAppGroupId = Bundle.main.object(forInfoDictionaryKey: kAppGroupIdKey) as? String
        
        appGroupId = customAppGroupId ?? defaultAppGroupId
    }
    
    @IBAction func done() {
        // Return any edited content to the host app.
        // This template doesn't do anything, so we just echo the passed in items.
        self.extensionContext!.completeRequest(returningItems: self.extensionContext!.inputItems, completionHandler: nil)
    }
}