Woka_Native_iOS/WOKA/Karaoke/Controller/AVAssetMods.swift

//
//  AVAssetMods.swift
//  WOKA
//
//  Created by MacBook Pro on 09/07/24.
//

import Foundation
import AVKit

extension AVAsset {
    
//    func writeAudioTrackToURL(_ url: URL, completion: @escaping (Bool, Error?, URL?) -> ()) {
//        DispatchQueue.global(qos: .userInitiated).async { [weak self] in
//            do {
//                guard let audioAsset = try self?.audioAsset() else {
//                    completion(false, nil, nil)
//                    return
//                }
//                audioAsset.writeToURL(url, completion: completion)
//            } catch let error as NSError {
//                DispatchQueue.main.async {
//                    completion(false, error, nil)
//                }
//            }
//        }
//    }
//
//    func writeToURL(_ url: URL, completion: @escaping (Bool, Error?, URL?) -> ()) {
//        DispatchQueue.global(qos: .userInitiated).async {
//            guard let exportSession = AVAssetExportSession(asset: self, presetName: AVAssetExportPresetAppleM4A) else {
//                DispatchQueue.main.async {
//                    completion(false, nil, nil)
//                }
//                return
//            }
//            
//            let audioMix = AVMutableAudioMix()
//            var inputParameters = [AVMutableAudioMixInputParameters]()
//            let volume: Float = 0.4
//            
//            for track in self.tracks(withMediaType: .audio) {
//                let audioInputParams = AVMutableAudioMixInputParameters(track: track)
//                audioInputParams.setVolume(volume, at: .zero)
//                inputParameters.append(audioInputParams)
//            }
//            
//            audioMix.inputParameters = inputParameters
//            exportSession.audioMix = audioMix
//            exportSession.outputFileType = .m4a
//            exportSession.outputURL = url
//            
//            DispatchQueue.main.async {
//                Utilities.startProgressHUD(msg: "Preparing")
//            }
//            
//            exportSession.exportAsynchronously {
//                DispatchQueue.main.async {
//                    switch exportSession.status {
//                    case .completed:
//                        Utilities.dismissProgressHUD()
//                        completion(true, nil, url)
//                    case .unknown, .waiting, .exporting, .failed, .cancelled:
//                        Utilities.dismissProgressHUD()
//                        completion(false, nil, nil)
//                    @unknown default:
//                        Utilities.dismissProgressHUD()
//                        completion(false, nil, nil)
//                    }
//                }
//            }
//        }
//    }

    func writeAudioTrackToURL(_ url: URL, completion: @escaping (Bool, Error?, URL?) -> ()) {
        do {
            let audioAsset = try self.audioAsset()
            audioAsset.writeToURL(url, completion: completion)
        } catch (let error as NSError){
            completion(false, error, nil)
        }
    }
    
    func writeToURL(_ url: URL, completion: @escaping (Bool, Error?, URL?) -> ()) {
        guard let exportSession = AVAssetExportSession(asset: self, presetName: AVAssetExportPresetAppleM4A) else {
            completion(false, nil , nil)
            return
        }
        
//        Utilities.startProgressHUD(msg: "Preparing")
        // Create an AVMutableAudioMix to adjust the volume
        let audioMix = AVMutableAudioMix()
        var inputParameters = [AVMutableAudioMixInputParameters]()
        
        // Decrease the volume by setting the volume to a value less than 1.0
        let volume : Float = 0.4 // Adjust the volume level as needed (e.g., 0.5 for half volume)
        
        // Create an AVMutableAudioMixInputParameters instance for each audio track
        for track in self.tracks(withMediaType: .audio) {
            let audioInputParams = AVMutableAudioMixInputParameters(track: track)
            audioInputParams.setVolume(volume, at: .zero) // Set the volume for the audio track
            inputParameters.append(audioInputParams)
        }
        
        // Assign the input parameters to the audio mix
        audioMix.inputParameters = inputParameters
        
        // Set the audio mix for the export session
        exportSession.audioMix = audioMix
        
        // Configure export session and start exporting
        exportSession.outputFileType = .m4a
        exportSession.outputURL = url
        
        exportSession.exportAsynchronously {
            switch exportSession.status {
            case .completed:
                Utilities.dismissProgressHUD()
                completion(true, nil, url)
            case .unknown, .waiting, .exporting, .failed, .cancelled:
                Utilities.dismissProgressHUD()
                completion(false, nil, nil)
            @unknown default:
                Utilities.dismissProgressHUD()
                completion(false, nil, nil)
            }
        }
    }
    
    func audioAsset() throws -> AVAsset {
        
        let composition = AVMutableComposition()
        let audioTracks = tracks(withMediaType: .audio)
        
        for track in audioTracks {
            
            let compositionTrack = composition.addMutableTrack(withMediaType: .audio, preferredTrackID: kCMPersistentTrackID_Invalid)
            try compositionTrack?.insertTimeRange(track.timeRange, of: track, at: track.timeRange.start)
            compositionTrack?.preferredTransform = track.preferredTransform
        }
        return composition
    }
}


extension FileManager {
    func clearTmpDirectory() {
        do {
            let tmpDirURL = FileManager.default.temporaryDirectory
            let tmpDirectory = try contentsOfDirectory(atPath: tmpDirURL.path)
            try tmpDirectory.forEach { file in
                let fileUrl = tmpDirURL.appendingPathComponent(file)
                try removeItem(atPath: fileUrl.path)
            }
        } catch {
           //catch the error somehow
        }
    }
}