//
//  LivePhoto.swift
//  NCLivePhoto
//
//  Created by Alexander Pagliaro on 7/25/18.
//  Copyright © 2018 Limit Point LLC. All rights reserved.
//

import UIKit
import AVFoundation
import MobileCoreServices
import Photos
import NextcloudKit
import UniformTypeIdentifiers
import Alamofire

class NCLivePhoto {

    var livePhotoFile = ""
    var livePhotoFile2 = ""

    // MARK: PUBLIC
    typealias LivePhotoResources = (pairedImage: URL, pairedVideo: URL)
    /// Returns the paired image and video for the given PHLivePhoto
    public class func extractResources(from livePhoto: PHLivePhoto, completion: @escaping (LivePhotoResources?) -> Void) {
        queue.async {
            shared.extractResources(from: livePhoto, completion: completion)
        }
    }
    /// Generates a PHLivePhoto from an image and video.  Also returns the paired image and video.
    public class func generate(from imageURL: URL?, videoURL: URL, progress: @escaping (CGFloat) -> Void, completion: @escaping (PHLivePhoto?, LivePhotoResources?) -> Void) {
        queue.async {
            shared.generate(from: imageURL, videoURL: videoURL, progress: progress, completion: completion)
        }
    }
    /// Save a Live Photo to the Photo Library by passing the paired image and video.
    public class func saveToLibrary(_ resources: LivePhotoResources, completion: @escaping (Bool) -> Void) {
        PHPhotoLibrary.shared().performChanges({
            let creationRequest = PHAssetCreationRequest.forAsset()
            let options = PHAssetResourceCreationOptions()
            creationRequest.addResource(with: PHAssetResourceType.pairedVideo, fileURL: resources.pairedVideo, options: options)
            creationRequest.addResource(with: PHAssetResourceType.photo, fileURL: resources.pairedImage, options: options)
        }, completionHandler: { success, error in
            if error != nil {
                print(error as Any)
            }
            completion(success)
        })
    }

    // MARK: PRIVATE
    private static let shared = NCLivePhoto()
    private static let queue = DispatchQueue(label: "com.limit-point.LivePhotoQueue", attributes: .concurrent)
    lazy private var cacheDirectory: URL? = {
        if let cacheDirectoryURL = try? FileManager.default.url(for: .cachesDirectory, in: .userDomainMask, appropriateFor: nil, create: false) {
            let fullDirectory = cacheDirectoryURL.appendingPathComponent("com.limit-point.LivePhoto", isDirectory: true)
            if !FileManager.default.fileExists(atPath: fullDirectory.absoluteString) {
                try? FileManager.default.createDirectory(at: fullDirectory, withIntermediateDirectories: true, attributes: nil)
            }
            return fullDirectory
        }
        return nil
    }()

    deinit {
        clearCache()
    }

    private func generateKeyPhoto(from videoURL: URL) -> URL? {
        var percent: Float = 0.5
        let videoAsset = AVURLAsset(url: videoURL)
        if let stillImageTime = videoAsset.stillImageTime() {
            percent = Float(stillImageTime.value) / Float(videoAsset.duration.value)
        }
        guard let imageFrame = videoAsset.getAssetFrame(percent: percent) else { return nil }
        guard let jpegData = imageFrame.jpegData(compressionQuality: 1) else { return nil }
        guard let url = cacheDirectory?.appendingPathComponent(UUID().uuidString).appendingPathExtension("jpg") else { return nil }
        do {
            try? jpegData.write(to: url)
            return url
        }
    }
    private func clearCache() {
        if let cacheDirectory = cacheDirectory {
            try? FileManager.default.removeItem(at: cacheDirectory)
        }
    }

    private func generate(from imageURL: URL?, videoURL: URL, progress: @escaping (CGFloat) -> Void, completion: @escaping (PHLivePhoto?, LivePhotoResources?) -> Void) {
        guard let cacheDirectory = cacheDirectory else {
            DispatchQueue.main.async {
                completion(nil, nil)
            }
            return
        }
        let assetIdentifier = UUID().uuidString
        let _keyPhotoURL = imageURL ?? generateKeyPhoto(from: videoURL)
        guard let keyPhotoURL = _keyPhotoURL, let pairedImageURL = addAssetID(assetIdentifier, toImage: keyPhotoURL, saveTo: cacheDirectory.appendingPathComponent(assetIdentifier).appendingPathExtension("jpg")) else {
            DispatchQueue.main.async {
                completion(nil, nil)
            }
            return
        }
        addAssetID(assetIdentifier, toVideo: videoURL, saveTo: cacheDirectory.appendingPathComponent(assetIdentifier).appendingPathExtension("mov"), progress: progress) { _videoURL in
            if let pairedVideoURL = _videoURL {
                _ = PHLivePhoto.request(withResourceFileURLs: [pairedVideoURL, pairedImageURL], placeholderImage: nil, targetSize: CGSize.zero, contentMode: PHImageContentMode.aspectFit, resultHandler: { (livePhoto: PHLivePhoto?, info: [AnyHashable: Any]) -> Void in
                    if let isDegraded = info[PHLivePhotoInfoIsDegradedKey] as? Bool, isDegraded {
                        return
                    }
                    DispatchQueue.main.async {
                        completion(livePhoto, (pairedImageURL, pairedVideoURL))
                    }
                })
            } else {
                DispatchQueue.main.async {
                    completion(nil, nil)
                }
            }
        }
    }

    private func extractResources(from livePhoto: PHLivePhoto, to directoryURL: URL, completion: @escaping (LivePhotoResources?) -> Void) {
        let assetResources = PHAssetResource.assetResources(for: livePhoto)
        let group = DispatchGroup()
        var keyPhotoURL: URL?
        var videoURL: URL?
        for resource in assetResources {
            let buffer = NSMutableData()
            let options = PHAssetResourceRequestOptions()
            options.isNetworkAccessAllowed = true
            group.enter()
            PHAssetResourceManager.default().requestData(for: resource, options: options, dataReceivedHandler: { data in
                buffer.append(data)
            }) { error in
                if error == nil {
                    if resource.type == .pairedVideo {
                        videoURL = self.saveAssetResource(resource, to: directoryURL, resourceData: buffer as Data)
                    } else {
                        keyPhotoURL = self.saveAssetResource(resource, to: directoryURL, resourceData: buffer as Data)
                    }
                } else {
                    print(error as Any)
                }
                group.leave()
            }
        }
        group.notify(queue: DispatchQueue.main) {
            guard let pairedPhotoURL = keyPhotoURL, let pairedVideoURL = videoURL else {
                return completion(nil)
            }
            completion((pairedPhotoURL, pairedVideoURL))
        }
    }

    private func extractResources(from livePhoto: PHLivePhoto, completion: @escaping (LivePhotoResources?) -> Void) {
        if let cacheDirectory = cacheDirectory {
            extractResources(from: livePhoto, to: cacheDirectory, completion: completion)
        }
    }

    private func saveAssetResource(_ resource: PHAssetResource, to directory: URL, resourceData: Data) -> URL? {
        guard let ext = UTType(tag: resource.uniformTypeIdentifier, tagClass: .filenameExtension, conformingTo: nil)?.identifier else { return nil }
        var fileUrl = directory.appendingPathComponent(NSUUID().uuidString)
        fileUrl = fileUrl.appendingPathExtension(ext as String)
        do {
            try resourceData.write(to: fileUrl, options: [Data.WritingOptions.atomic])
        } catch {
            print("Could not save resource \(resource) to filepath \(String(describing: fileUrl))")
            return nil
        }
        return fileUrl
    }

    func addAssetID(_ assetIdentifier: String, toImage imageURL: URL, saveTo destinationURL: URL) -> URL? {
        guard let imageDestination = CGImageDestinationCreateWithURL(destinationURL as CFURL, UTType.jpeg.identifier as CFString, 1, nil),
            let imageSource = CGImageSourceCreateWithURL(imageURL as CFURL, nil),
            var imageProperties = CGImageSourceCopyPropertiesAtIndex(imageSource, 0, nil) as? [AnyHashable: Any] else { return nil }
        let assetIdentifierKey = "17"
        let assetIdentifierInfo = [assetIdentifierKey: assetIdentifier]
        imageProperties[kCGImagePropertyMakerAppleDictionary] = assetIdentifierInfo
        CGImageDestinationAddImageFromSource(imageDestination, imageSource, 0, imageProperties as CFDictionary)
        CGImageDestinationFinalize(imageDestination)
        return destinationURL
    }

    var audioReader: AVAssetReader?
    var videoReader: AVAssetReader?
    var assetWriter: AVAssetWriter?

    func addAssetID(_ assetIdentifier: String, toVideo videoURL: URL, saveTo destinationURL: URL, progress: @escaping (CGFloat) -> Void, completion: @escaping (URL?) -> Void) {

        var audioWriterInput: AVAssetWriterInput?
        var audioReaderOutput: AVAssetReaderOutput?
        let videoAsset = AVURLAsset(url: videoURL)
        let frameCount = videoAsset.countFrames(exact: false)
        guard let videoTrack = videoAsset.tracks(withMediaType: .video).first else {
            return completion(nil)
        }
        do {
            // Create the Asset Writer
            assetWriter = try AVAssetWriter(outputURL: destinationURL, fileType: .mov)
            // Create Video Reader Output
            videoReader = try AVAssetReader(asset: videoAsset)
            let videoReaderSettings = [kCVPixelBufferPixelFormatTypeKey as String: NSNumber(value: kCVPixelFormatType_32BGRA as UInt32)]
            let videoReaderOutput = AVAssetReaderTrackOutput(track: videoTrack, outputSettings: videoReaderSettings)
            videoReader?.add(videoReaderOutput)
            // Create Video Writer Input
            let videoWriterInput = AVAssetWriterInput(mediaType: .video, outputSettings: [AVVideoCodecKey: AVVideoCodecType.h264, AVVideoWidthKey: videoTrack.naturalSize.width, AVVideoHeightKey: videoTrack.naturalSize.height])
            videoWriterInput.transform = videoTrack.preferredTransform
            videoWriterInput.expectsMediaDataInRealTime = true
            assetWriter?.add(videoWriterInput)
            // Create Audio Reader Output & Writer Input
            if let audioTrack = videoAsset.tracks(withMediaType: .audio).first {
                do {
                    let _audioReader = try AVAssetReader(asset: videoAsset)
                    let _audioReaderOutput = AVAssetReaderTrackOutput(track: audioTrack, outputSettings: nil)
                    _audioReader.add(_audioReaderOutput)
                    audioReader = _audioReader
                    audioReaderOutput = _audioReaderOutput
                    let _audioWriterInput = AVAssetWriterInput(mediaType: .audio, outputSettings: nil)
                    _audioWriterInput.expectsMediaDataInRealTime = false
                    assetWriter?.add(_audioWriterInput)
                    audioWriterInput = _audioWriterInput
                } catch {
                    print(error)
                }
            }
            // Create necessary identifier metadata and still image time metadata
            let assetIdentifierMetadata = metadataForAssetID(assetIdentifier)
            let stillImageTimeMetadataAdapter = createMetadataAdaptorForStillImageTime()
            assetWriter?.metadata = [assetIdentifierMetadata]
            assetWriter?.add(stillImageTimeMetadataAdapter.assetWriterInput)
            // Start the Asset Writer
            assetWriter?.startWriting()
            assetWriter?.startSession(atSourceTime: CMTime.zero)
            // Add still image metadata
            let _stillImagePercent: Float = 0.5
            stillImageTimeMetadataAdapter.append(AVTimedMetadataGroup(items: [metadataItemForStillImageTime()], timeRange: videoAsset.makeStillImageTimeRange(percent: _stillImagePercent, inFrameCount: frameCount)))
            // For end of writing / progress
            var writingVideoFinished = false
            var writingAudioFinished = false
            var currentFrameCount = 0
            func didCompleteWriting() {
                guard writingAudioFinished && writingVideoFinished else { return }
                assetWriter?.finishWriting {
                    if self.assetWriter?.status == .completed {
                        completion(destinationURL)
                    } else {
                        completion(nil)
                    }
                }
            }
            // Start writing video
            if videoReader?.startReading() ?? false {
                videoWriterInput.requestMediaDataWhenReady(on: DispatchQueue(label: "videoWriterInputQueue")) {
                    while videoWriterInput.isReadyForMoreMediaData {
                        if let sampleBuffer = videoReaderOutput.copyNextSampleBuffer() {
                            currentFrameCount += 1
                            let percent: CGFloat = CGFloat(currentFrameCount) / CGFloat(frameCount)
                            progress(percent)
                            if !videoWriterInput.append(sampleBuffer) {
                                print("Cannot write: \(String(describing: self.assetWriter?.error?.localizedDescription))")
                                self.videoReader?.cancelReading()
                            }
                        } else {
                            videoWriterInput.markAsFinished()
                            writingVideoFinished = true
                            didCompleteWriting()
                        }
                    }
                }
            } else {
                writingVideoFinished = true
                didCompleteWriting()
            }
            // Start writing audio
            if audioReader?.startReading() ?? false {
                audioWriterInput?.requestMediaDataWhenReady(on: DispatchQueue(label: "audioWriterInputQueue")) {
                    while audioWriterInput?.isReadyForMoreMediaData ?? false {
                        guard let sampleBuffer = audioReaderOutput?.copyNextSampleBuffer() else {
                            audioWriterInput?.markAsFinished()
                            writingAudioFinished = true
                            didCompleteWriting()
                            return
                        }
                        audioWriterInput?.append(sampleBuffer)
                    }
                }
            } else {
                writingAudioFinished = true
                didCompleteWriting()
            }
        } catch {
            print(error)
            completion(nil)
        }
    }

    private func metadataForAssetID(_ assetIdentifier: String) -> AVMetadataItem {
        let item = AVMutableMetadataItem()
        let keyContentIdentifier = "com.apple.quicktime.content.identifier"
        let keySpaceQuickTimeMetadata = "mdta"
        item.key = keyContentIdentifier as (NSCopying & NSObjectProtocol)?
        item.keySpace = AVMetadataKeySpace(rawValue: keySpaceQuickTimeMetadata)
        item.value = assetIdentifier as (NSCopying & NSObjectProtocol)?
        item.dataType = "com.apple.metadata.datatype.UTF-8"
        return item
    }

    private func createMetadataAdaptorForStillImageTime() -> AVAssetWriterInputMetadataAdaptor {
        let keyStillImageTime = "com.apple.quicktime.still-image-time"
        let keySpaceQuickTimeMetadata = "mdta"
        let spec: NSDictionary = [
            kCMMetadataFormatDescriptionMetadataSpecificationKey_Identifier as NSString:
            "\(keySpaceQuickTimeMetadata)/\(keyStillImageTime)",
            kCMMetadataFormatDescriptionMetadataSpecificationKey_DataType as NSString:
            "com.apple.metadata.datatype.int8"            ]
        var desc: CMFormatDescription?
        CMMetadataFormatDescriptionCreateWithMetadataSpecifications(allocator: kCFAllocatorDefault, metadataType: kCMMetadataFormatType_Boxed, metadataSpecifications: [spec] as CFArray, formatDescriptionOut: &desc)
        let input = AVAssetWriterInput(mediaType: .metadata,
                                       outputSettings: nil, sourceFormatHint: desc)
        return AVAssetWriterInputMetadataAdaptor(assetWriterInput: input)
    }

    private func metadataItemForStillImageTime() -> AVMetadataItem {
        let item = AVMutableMetadataItem()
        let keyStillImageTime = "com.apple.quicktime.still-image-time"
        let keySpaceQuickTimeMetadata = "mdta"
        item.key = keyStillImageTime as (NSCopying & NSObjectProtocol)?
        item.keySpace = AVMetadataKeySpace(rawValue: keySpaceQuickTimeMetadata)
        item.value = 0 as (NSCopying & NSObjectProtocol)?
        item.dataType = "com.apple.metadata.datatype.int8"
        return item
    }

}

fileprivate extension AVAsset {
    func countFrames(exact: Bool) -> Int {

        var frameCount = 0

        if let videoReader = try? AVAssetReader(asset: self) {

            if let videoTrack = self.tracks(withMediaType: .video).first {

                frameCount = Int(CMTimeGetSeconds(self.duration) * Float64(videoTrack.nominalFrameRate))

                if exact {

                    frameCount = 0

                    let videoReaderOutput = AVAssetReaderTrackOutput(track: videoTrack, outputSettings: nil)
                    videoReader.add(videoReaderOutput)

                    videoReader.startReading()

                    // count frames
                    while true {
                        let sampleBuffer = videoReaderOutput.copyNextSampleBuffer()
                        if sampleBuffer == nil {
                            break
                        }
                        frameCount += 1
                    }

                    videoReader.cancelReading()
                }

            }
        }

        return frameCount
    }

    func stillImageTime() -> CMTime? {

        var stillTime: CMTime?

        if let videoReader = try? AVAssetReader(asset: self) {

            if let metadataTrack = self.tracks(withMediaType: .metadata).first {

                let videoReaderOutput = AVAssetReaderTrackOutput(track: metadataTrack, outputSettings: nil)

                videoReader.add(videoReaderOutput)

                videoReader.startReading()

                let keyStillImageTime = "com.apple.quicktime.still-image-time"
                let keySpaceQuickTimeMetadata = "mdta"

                var found = false

                while found == false {
                    if let sampleBuffer = videoReaderOutput.copyNextSampleBuffer() {
                        if CMSampleBufferGetNumSamples(sampleBuffer) != 0 {
                            let group = AVTimedMetadataGroup(sampleBuffer: sampleBuffer)
                            for item in group?.items ?? [] {
                                if item.key as? String == keyStillImageTime && item.keySpace!.rawValue == keySpaceQuickTimeMetadata {
                                    stillTime = group?.timeRange.start
                                    // print("stillImageTime = \(CMTimeGetSeconds(stillTime!))")
                                    found = true
                                    break
                                }
                            }
                        }
                    } else {
                        break
                    }
                }

                videoReader.cancelReading()

            }
        }

        return stillTime
    }

    func makeStillImageTimeRange(percent: Float, inFrameCount: Int = 0) -> CMTimeRange {

        var time = self.duration

        var frameCount = inFrameCount

        if frameCount == 0 {
            frameCount = self.countFrames(exact: true)
        }

        let frameDuration = Int64(Float(time.value) / Float(frameCount))

        time.value = Int64(Float(time.value) * percent)

        // print("stillImageTime = \(CMTimeGetSeconds(time))")

        return CMTimeRangeMake(start: time, duration: CMTimeMake(value: frameDuration, timescale: time.timescale))
    }

    func getAssetFrame(percent: Float) -> UIImage? {

        let imageGenerator = AVAssetImageGenerator(asset: self)
        imageGenerator.appliesPreferredTrackTransform = true

        imageGenerator.requestedTimeToleranceAfter = CMTimeMake(value: 1, timescale: 100)
        imageGenerator.requestedTimeToleranceBefore = CMTimeMake(value: 1, timescale: 100)

        var time = self.duration

        time.value = Int64(Float(time.value) * percent)

        do {
            var actualTime = CMTime.zero
            let imageRef = try imageGenerator.copyCGImage(at: time, actualTime: &actualTime)

            let img = UIImage(cgImage: imageRef)

            return img
        } catch let error as NSError {
            print("Image generation failed with error \(error)")
            return nil
        }
    }
}

extension NCLivePhoto {
    func setLivephoto(serverUrlfileNamePath: String,
                      livePhotoFile: String,
                      account: String,
                      options: NKRequestOptions = NKRequestOptions()) async -> (account: String, responseData: AFDataResponse<Data?>?, error: NKError) {
        await withUnsafeContinuation({ continuation in
            NextcloudKit.shared.setLivephoto(serverUrlfileNamePath: serverUrlfileNamePath, livePhotoFile: livePhotoFile, account: account, options: options) { account, responseData, error in
                continuation.resume(returning: (account: account, responseData: responseData,error: error))
            }
        })
    }

    func setLivephotoUpload(metadata: tableMetadata) {
        guard NCCapabilities.shared.getCapabilities(account: metadata.account).capabilityServerVersionMajor >= NCGlobal.shared.nextcloudVersion28 else { return }

        livePhotoFile = metadata.livePhotoFile
        livePhotoFile2 = metadata.fileName

        if livePhotoFile.isEmpty {
            if metadata.classFile == NKCommon.TypeClassFile.image.rawValue {
                livePhotoFile = (metadata.fileName as NSString).deletingPathExtension + ".mov"
            } else if metadata.classFile == NKCommon.TypeClassFile.video.rawValue {
                livePhotoFile = (metadata.fileName as NSString).deletingPathExtension + ".jpg"
            }
        }

        guard metadata.isLivePhoto,
              !livePhotoFile.isEmpty,
              let metadata2 = NCManageDatabase.shared.getMetadata(predicate: NSPredicate(format: "account == %@ AND urlBase == %@ AND path == %@ AND fileName == %@ AND status == %d", 
                                                                                         metadata.account,
                                                                                         metadata.urlBase,
                                                                                         metadata.path,
                                                                                         livePhotoFile,
                                                                                         NCGlobal.shared.metadataStatusNormal)) else { return }
        let serverUrlfileNamePath1 = metadata.urlBase + metadata.path + metadata.fileName
        let serverUrlfileNamePath2 = metadata2.urlBase + metadata2.path + livePhotoFile

        Task {
            if metadata.livePhotoFile.isEmpty {
                _ = await setLivephoto(serverUrlfileNamePath: serverUrlfileNamePath1, livePhotoFile: livePhotoFile, account: metadata.account)
            }
            if metadata2.livePhotoFile.isEmpty {
                _ = await setLivephoto(serverUrlfileNamePath: serverUrlfileNamePath2, livePhotoFile: livePhotoFile2, account: metadata2.account)
            }
        }
    }

    func setLivePhoto(metadata1: tableMetadata, metadata2: tableMetadata) {
        guard NCCapabilities.shared.getCapabilities(account: metadata1.account).capabilityServerVersionMajor >= NCGlobal.shared.nextcloudVersion28,
              (!metadata1.livePhotoFile.isEmpty && !metadata2.livePhotoFile.isEmpty) else { return }

        Task {
            if metadata1.livePhotoFile.isEmpty {
                let serverUrlfileNamePath = metadata1.urlBase + metadata1.path + metadata1.fileName
                _ = await setLivephoto(serverUrlfileNamePath: serverUrlfileNamePath, livePhotoFile: metadata2.fileName, account: metadata2.account)
            }
            if metadata2.livePhotoFile.isEmpty {
                let serverUrlfileNamePath = metadata2.urlBase + metadata2.path + metadata2.fileName
                _ = await setLivephoto(serverUrlfileNamePath: serverUrlfileNamePath, livePhotoFile: metadata1.fileName, account: metadata1.account)
            }
        }
    }
}