AquaStream/app/src/main/java/com/lagradost/cloudstream3/utils/VideoDownloadManager.kt

package com.lagradost.cloudstream3.utils

import android.app.Notification
import android.app.NotificationChannel
import android.app.NotificationManager
import android.app.PendingIntent
import android.content.*
import android.graphics.Bitmap
import android.net.Uri
import android.os.Build
import android.os.Environment
import android.provider.MediaStore
import androidx.annotation.DrawableRes
import androidx.annotation.RequiresApi
import androidx.core.app.NotificationCompat
import androidx.core.app.NotificationManagerCompat
import androidx.core.net.toUri
import androidx.work.Data
import androidx.work.ExistingWorkPolicy
import androidx.work.OneTimeWorkRequest
import androidx.work.WorkManager
import com.bumptech.glide.Glide
import com.fasterxml.jackson.annotation.JsonProperty
import com.lagradost.cloudstream3.MainActivity
import com.lagradost.cloudstream3.R
import com.lagradost.cloudstream3.mvvm.logError
import com.lagradost.cloudstream3.mvvm.normalSafeApiCall
import com.lagradost.cloudstream3.services.VideoDownloadService
import com.lagradost.cloudstream3.utils.Coroutines.main
import com.lagradost.cloudstream3.utils.DataStore.getKey
import com.lagradost.cloudstream3.utils.DataStore.removeKey
import com.lagradost.cloudstream3.utils.DataStore.setKey
import com.lagradost.cloudstream3.utils.UIHelper.colorFromAttribute
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.delay
import kotlinx.coroutines.withContext
import java.io.*
import java.lang.Thread.sleep
import java.net.URI
import java.net.URL
import java.net.URLConnection
import java.util.*
import kotlin.math.roundToInt

const val DOWNLOAD_CHANNEL_ID = "cloudstream3.general"
const val DOWNLOAD_CHANNEL_NAME = "Downloads"
const val DOWNLOAD_CHANNEL_DESCRIPT = "The download notification channel"

object VideoDownloadManager {
    var maxConcurrentDownloads = 3
    private var currentDownloads = mutableListOf<Int>()

    private const val USER_AGENT =
        "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36"

    @DrawableRes
    const val imgDone = R.drawable.rddone

    @DrawableRes
    const val imgDownloading = R.drawable.rdload

    @DrawableRes
    const val imgPaused = R.drawable.rdpause

    @DrawableRes
    const val imgStopped = R.drawable.rderror

    @DrawableRes
    const val imgError = R.drawable.rderror

    @DrawableRes
    const val pressToPauseIcon = R.drawable.ic_baseline_pause_24

    @DrawableRes
    const val pressToResumeIcon = R.drawable.ic_baseline_play_arrow_24

    @DrawableRes
    const val pressToStopIcon = R.drawable.exo_icon_stop

    enum class DownloadType {
        IsPaused,
        IsDownloading,
        IsDone,
        IsFailed,
        IsStopped,
    }

    enum class DownloadActionType {
        Pause,
        Resume,
        Stop,
    }

    interface IDownloadableMinimum {
        val url: String
        val referer: String
        val headers: Map<String, String>
    }

    fun IDownloadableMinimum.getId(): Int {
        return url.hashCode()
    }

    data class DownloadEpisodeMetadata(
        val id: Int,
        val mainName: String,
        val sourceApiName: String?,
        val poster: String?,
        val name: String?,
        val season: Int?,
        val episode: Int?
    )

    data class DownloadItem(
        val source: String?,
        val folder: String?,
        val ep: DownloadEpisodeMetadata,
        val links: List<ExtractorLink>,
    )

    data class DownloadResumePackage(
        val item: DownloadItem,
        val linkIndex: Int?,
    )

    data class DownloadedFileInfo(
        val totalBytes: Long,
        val relativePath: String,
        val displayName: String,
        val extraInfo: String? = null
    )

    data class DownloadedFileInfoResult(
        val fileLength: Long,
        val totalBytes: Long,
        val path: Uri,
    )

    data class DownloadQueueResumePackage(
        val index: Int,
        val pkg: DownloadResumePackage,
    )

    private const val SUCCESS_DOWNLOAD_DONE = 1
    private const val SUCCESS_STREAM = 3
    private const val SUCCESS_STOPPED = 2
    private const val ERROR_DELETING_FILE = 3 // will not download the next one, but is still classified as an error
    private const val ERROR_CREATE_FILE = -2
    private const val ERROR_UNKNOWN = -10
    private const val ERROR_OPEN_FILE = -3
    private const val ERROR_TOO_SMALL_CONNECTION = -4
    private const val ERROR_WRONG_CONTENT = -5
    private const val ERROR_CONNECTION_ERROR = -6
    private const val ERROR_MEDIA_STORE_URI_CANT_BE_CREATED = -7
    private const val ERROR_CONTENT_RESOLVER_CANT_OPEN_STREAM = -8
    private const val ERROR_CONTENT_RESOLVER_NOT_FOUND = -9

    private const val KEY_RESUME_PACKAGES = "download_resume"
    const val KEY_DOWNLOAD_INFO = "download_info"
    private const val KEY_RESUME_QUEUE_PACKAGES = "download_q_resume"

    val downloadStatus = HashMap<Int, DownloadType>()
    val downloadStatusEvent = Event<Pair<Int, DownloadType>>()
    val downloadDeleteEvent = Event<Int>()
    val downloadEvent = Event<Pair<Int, DownloadActionType>>()
    val downloadProgressEvent = Event<Triple<Int, Long, Long>>()
    val downloadQueue = LinkedList<DownloadResumePackage>()

    private var hasCreatedNotChanel = false
    private fun Context.createNotificationChannel() {
        hasCreatedNotChanel = true
        // Create the NotificationChannel, but only on API 26+ because
        // the NotificationChannel class is new and not in the support library
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            val name = DOWNLOAD_CHANNEL_NAME //getString(R.string.channel_name)
            val descriptionText = DOWNLOAD_CHANNEL_DESCRIPT//getString(R.string.channel_description)
            val importance = NotificationManager.IMPORTANCE_DEFAULT
            val channel = NotificationChannel(DOWNLOAD_CHANNEL_ID, name, importance).apply {
                description = descriptionText
            }
            // Register the channel with the system
            val notificationManager: NotificationManager =
                this.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
            notificationManager.createNotificationChannel(channel)
        }
    }

    /** Will return IsDone if not found or error */
    fun getDownloadState(id: Int): DownloadType {
        return try {
            downloadStatus[id] ?: DownloadType.IsDone
        } catch (e: Exception) {
            logError(e)
            DownloadType.IsDone
        }
    }

    private val cachedBitmaps = hashMapOf<String, Bitmap>()
    private fun Context.getImageBitmapFromUrl(url: String): Bitmap? {
        try {
            if (cachedBitmaps.containsKey(url)) {
                return cachedBitmaps[url]
            }

            val bitmap = GlideApp.with(this)
                .asBitmap()
                .load(url).into(720, 720)
                .get()
            if (bitmap != null) {
                cachedBitmaps[url] = bitmap
            }
            return null
        } catch (e: Exception) {
            return null
        }
    }

    suspend fun createNotification(
        context: Context,
        source: String?,
        linkName: String?,
        ep: DownloadEpisodeMetadata,
        state: DownloadType,
        progress: Long,
        total: Long,
        notificationCallback: (Int, Notification) -> Unit

    ): Notification? {
        if (total <= 0) return null// crash, invalid data

//        main { // DON'T WANT TO SLOW IT DOWN
        val builder = NotificationCompat.Builder(context, DOWNLOAD_CHANNEL_ID)
            .setAutoCancel(true)
            .setColorized(true)
            .setOnlyAlertOnce(true)
            .setShowWhen(false)
            .setPriority(NotificationCompat.PRIORITY_DEFAULT)
            .setColor(context.colorFromAttribute(R.attr.colorPrimary))
            .setContentTitle(ep.mainName)
            .setSmallIcon(
                when (state) {
                    DownloadType.IsDone -> imgDone
                    DownloadType.IsDownloading -> imgDownloading
                    DownloadType.IsPaused -> imgPaused
                    DownloadType.IsFailed -> imgError
                    DownloadType.IsStopped -> imgStopped
                }
            )

        if (ep.sourceApiName != null) {
            builder.setSubText(ep.sourceApiName)
        }

        if (source != null) {
            val intent = Intent(context, MainActivity::class.java).apply {
                data = source.toUri()
                flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
            }
            val pendingIntent: PendingIntent = PendingIntent.getActivity(context, 0, intent, 0)
            builder.setContentIntent(pendingIntent)
        }

        if (state == DownloadType.IsDownloading || state == DownloadType.IsPaused) {
            builder.setProgress((total / 1000).toInt(), (progress / 1000).toInt(), false)
        }

        val rowTwoExtra = if (ep.name != null) " - ${ep.name}\n" else ""
        val rowTwo = if (ep.season != null && ep.episode != null) {
            "${context.getString(R.string.season_short)}${ep.season}:${context.getString(R.string.episode_short)}${ep.episode}" + rowTwoExtra
        } else if (ep.episode != null) {
            "${context.getString(R.string.episode)} ${ep.episode}" + rowTwoExtra
        } else {
            (ep.name ?: "") + ""
        }
        val downloadFormat = context.getString(R.string.download_format)

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            if (ep.poster != null) {
                val poster = withContext(Dispatchers.IO) {
                    context.getImageBitmapFromUrl(ep.poster)
                }
                if (poster != null)
                    builder.setLargeIcon(poster)
            }

            val progressPercentage = progress * 100 / total
            val progressMbString = "%.1f".format(progress / 1000000f)
            val totalMbString = "%.1f".format(total / 1000000f)
            val bigText =
                if (state == DownloadType.IsDownloading || state == DownloadType.IsPaused) {
                    (if (linkName == null) "" else "$linkName\n") + "$rowTwo\n$progressPercentage % ($progressMbString MB/$totalMbString MB)"
                } else if (state == DownloadType.IsFailed) {
                    downloadFormat.format(context.getString(R.string.download_failed), rowTwo)
                } else if (state == DownloadType.IsDone) {
                    downloadFormat.format(context.getString(R.string.download_done), rowTwo)
                } else {
                    downloadFormat.format(context.getString(R.string.download_canceled), rowTwo)
                }

            val bodyStyle = NotificationCompat.BigTextStyle()
            bodyStyle.bigText(bigText)
            builder.setStyle(bodyStyle)
        } else {
            val txt = if (state == DownloadType.IsDownloading || state == DownloadType.IsPaused) {
                rowTwo
            } else if (state == DownloadType.IsFailed) {
                downloadFormat.format(context.getString(R.string.download_failed), rowTwo)
            } else if (state == DownloadType.IsDone) {
                downloadFormat.format(context.getString(R.string.download_done), rowTwo)
            } else {
                downloadFormat.format(context.getString(R.string.download_canceled), rowTwo)
            }

            builder.setContentText(txt)
        }

        if ((state == DownloadType.IsDownloading || state == DownloadType.IsPaused) && Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            val actionTypes: MutableList<DownloadActionType> = ArrayList()
            // INIT
            if (state == DownloadType.IsDownloading) {
                actionTypes.add(DownloadActionType.Pause)
                actionTypes.add(DownloadActionType.Stop)
            }

            if (state == DownloadType.IsPaused) {
                actionTypes.add(DownloadActionType.Resume)
                actionTypes.add(DownloadActionType.Stop)
            }

            // ADD ACTIONS
            for ((index, i) in actionTypes.withIndex()) {
                val actionResultIntent = Intent(context, VideoDownloadService::class.java)

                actionResultIntent.putExtra(
                    "type", when (i) {
                        DownloadActionType.Resume -> "resume"
                        DownloadActionType.Pause -> "pause"
                        DownloadActionType.Stop -> "stop"
                    }
                )

                actionResultIntent.putExtra("id", ep.id)

                val pending: PendingIntent = PendingIntent.getService(
                    // BECAUSE episodes lying near will have the same id +1, index will give the same requested as the previous episode, *100000 fixes this
                    context, (4337 + index * 100000 + ep.id),
                    actionResultIntent,
                    PendingIntent.FLAG_UPDATE_CURRENT
                )

                builder.addAction(
                    NotificationCompat.Action(
                        when (i) {
                            DownloadActionType.Resume -> pressToResumeIcon
                            DownloadActionType.Pause -> pressToPauseIcon
                            DownloadActionType.Stop -> pressToStopIcon
                        }, when (i) {
                            DownloadActionType.Resume -> context.getString(R.string.resume)
                            DownloadActionType.Pause -> context.getString(R.string.pause)
                            DownloadActionType.Stop -> context.getString(R.string.cancel)
                        }, pending
                    )
                )
            }
        }

        if (!hasCreatedNotChanel) {
            context.createNotificationChannel()
        }

        val notification = builder.build()
        notificationCallback(ep.id, notification)
        with(NotificationManagerCompat.from(context)) {
            // notificationId is a unique int for each notification that you must define
            notify(ep.id, notification)
        }
        return notification

//        }
    }

    private const val reservedChars = "|\\?*<\":>+[]/\'"
    fun sanitizeFilename(name: String): String {
        var tempName = name
        for (c in reservedChars) {
            tempName = tempName.replace(c, ' ')
        }
        return tempName.replace("  ", " ").trim(' ')
    }

    @RequiresApi(Build.VERSION_CODES.Q)
    private fun ContentResolver.getExistingFolderStartName(relativePath: String): List<Pair<String, Uri>>? {
        try {
            val projection = arrayOf(
                MediaStore.MediaColumns._ID,
                MediaStore.MediaColumns.DISPLAY_NAME,   // unused (for verification use only)
                //MediaStore.MediaColumns.RELATIVE_PATH,  // unused (for verification use only)
            )

            val selection =
                "${MediaStore.MediaColumns.RELATIVE_PATH}='$relativePath'"

            val result = this.query(
                MediaStore.Downloads.getContentUri(MediaStore.VOLUME_EXTERNAL_PRIMARY),
                projection, selection, null, null
            )
            val list = ArrayList<Pair<String, Uri>>()

            result.use { c ->
                if (c != null && c.count >= 1) {
                    c.moveToFirst()
                    while (true) {
                        val id = c.getLong(c.getColumnIndexOrThrow(MediaStore.MediaColumns._ID))
                        val name = c.getString(c.getColumnIndexOrThrow(MediaStore.MediaColumns.DISPLAY_NAME))
                        val uri = ContentUris.withAppendedId(
                            MediaStore.Downloads.EXTERNAL_CONTENT_URI, id
                        )
                        list.add(Pair(name, uri))
                        if (c.isLast) {
                            break
                        }
                        c.moveToNext()
                    }

                    /*
                    val cDisplayName = c.getString(c.getColumnIndexOrThrow(MediaStore.MediaColumns.DISPLAY_NAME))
                    val cRelativePath = c.getString(c.getColumnIndexOrThrow(MediaStore.MediaColumns.RELATIVE_PATH))*/

                }
            }
            return list
        } catch (e: Exception) {
            return null
        }
    }

    fun getFolder(context: Context, relativePath: String): List<Pair<String, Uri>>? {
        if (isScopedStorage()) {
            return context.contentResolver?.getExistingFolderStartName(relativePath)
        } else {
            val normalPath =
                "${Environment.getExternalStorageDirectory()}${File.separatorChar}${relativePath}".replace(
                    '/',
                    File.separatorChar
                )
            val folder = File(normalPath)
            if (folder.isDirectory) {
                return folder.listFiles()?.map { Pair(it.name, it.toUri()) }
            }
            return null
        }
    }

    @RequiresApi(Build.VERSION_CODES.Q)
    private fun ContentResolver.getExistingDownloadUriOrNullQ(relativePath: String, displayName: String): Uri? {
        try {
            val projection = arrayOf(
                MediaStore.MediaColumns._ID,
                //MediaStore.MediaColumns.DISPLAY_NAME,   // unused (for verification use only)
                //MediaStore.MediaColumns.RELATIVE_PATH,  // unused (for verification use only)
            )

            val selection =
                "${MediaStore.MediaColumns.RELATIVE_PATH}='$relativePath' AND " + "${MediaStore.MediaColumns.DISPLAY_NAME}='$displayName'"

            val result = this.query(
                MediaStore.Downloads.getContentUri(MediaStore.VOLUME_EXTERNAL_PRIMARY),
                projection, selection, null, null
            )

            result.use { c ->
                if (c != null && c.count >= 1) {
                    c.moveToFirst().let {
                        val id = c.getLong(c.getColumnIndexOrThrow(MediaStore.MediaColumns._ID))
                        /*
                        val cDisplayName = c.getString(c.getColumnIndexOrThrow(MediaStore.MediaColumns.DISPLAY_NAME))
                        val cRelativePath = c.getString(c.getColumnIndexOrThrow(MediaStore.MediaColumns.RELATIVE_PATH))*/

                        return ContentUris.withAppendedId(
                            MediaStore.Downloads.EXTERNAL_CONTENT_URI, id
                        )
                    }
                }
            }
            return null
        } catch (e: Exception) {
            return null
        }
    }

    @RequiresApi(Build.VERSION_CODES.Q)
    fun ContentResolver.getFileLength(fileUri: Uri): Long? {
        return try {
            this.openFileDescriptor(fileUri, "r")
                .use { it?.statSize ?: 0 }
        } catch (e: Exception) {
            null
        }
    }

    private fun isScopedStorage(): Boolean {
        return Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q
    }

    data class CreateNotificationMetadata(
        val type: DownloadType,
        val bytesDownloaded: Long,
        val bytesTotal: Long,
    )

    data class StreamData(
        val errorCode: Int,
        val resume: Boolean? = null,
        val fileLength: Long? = null,
        val fileStream: OutputStream? = null,
    )

    private fun setupStream(
        context: Context,
        name: String,
        folder: String?,
        extension: String,
        tryResume: Boolean,
    ): StreamData {
        val relativePath = getRelativePath(folder)
        val displayName = getDisplayName(name, extension)
        val fileStream: OutputStream
        val fileLength: Long
        var resume = tryResume
        if (isScopedStorage()) {
            val cr = context.contentResolver ?: return StreamData(ERROR_CONTENT_RESOLVER_NOT_FOUND)

            val currentExistingFile =
                cr.getExistingDownloadUriOrNullQ(relativePath, displayName) // CURRENT FILE WITH THE SAME PATH

            fileLength =
                if (currentExistingFile == null || !resume) 0 else (cr.getFileLength(currentExistingFile)
                    ?: 0)// IF NOT RESUME THEN 0, OTHERWISE THE CURRENT FILE SIZE

            if (!resume && currentExistingFile != null) { // DELETE FILE IF FILE EXITS AND NOT RESUME
                val rowsDeleted = context.contentResolver.delete(currentExistingFile, null, null)
                if (rowsDeleted < 1) {
                    println("ERROR DELETING FILE!!!")
                }
            }

            var appendFile = false
            val newFileUri = if (resume && currentExistingFile != null) {
                appendFile = true
                currentExistingFile
            } else {
                val contentUri =
                    MediaStore.Downloads.getContentUri(MediaStore.VOLUME_EXTERNAL_PRIMARY) // USE INSTEAD OF MediaStore.Downloads.EXTERNAL_CONTENT_URI
                //val currentMimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension)
                val currentMimeType = when (extension) {
                    "vtt" -> "text/vtt"
                    "mp4" -> "video/mp4"
                    "srt" -> "application/x-subrip"//"text/plain"
                    else -> null
                }
                val newFile = ContentValues().apply {
                    put(MediaStore.MediaColumns.DISPLAY_NAME, displayName)
                    put(MediaStore.MediaColumns.TITLE, name)
                    if (currentMimeType != null)
                        put(MediaStore.MediaColumns.MIME_TYPE, currentMimeType)
                    put(MediaStore.MediaColumns.RELATIVE_PATH, relativePath)
                }

                cr.insert(
                    contentUri,
                    newFile
                ) ?: return StreamData(ERROR_CONTENT_RESOLVER_NOT_FOUND)
            }

            fileStream = cr.openOutputStream(newFileUri, "w" + (if (appendFile) "a" else ""))
                ?: return StreamData(ERROR_CONTENT_RESOLVER_NOT_FOUND)
        } else {
            val normalPath = getNormalPath(relativePath, displayName)
            // NORMAL NON SCOPED STORAGE FILE CREATION
            val rFile = File(normalPath)
            if (!rFile.exists()) {
                fileLength = 0
                rFile.parentFile?.mkdirs()
                if (!rFile.createNewFile()) return StreamData(ERROR_CONTENT_RESOLVER_NOT_FOUND)
            } else {
                if (resume) {
                    fileLength = rFile.length()
                } else {
                    fileLength = 0
                    rFile.parentFile?.mkdirs()
                    if (!rFile.delete()) return StreamData(ERROR_CONTENT_RESOLVER_NOT_FOUND)
                    if (!rFile.createNewFile()) return StreamData(ERROR_CONTENT_RESOLVER_NOT_FOUND)
                }
            }
            fileStream = FileOutputStream(rFile, false)
        }
        if (fileLength == 0L) resume = false
        return StreamData(SUCCESS_STREAM, resume, fileLength, fileStream)
    }

    fun downloadThing(
        context: Context,
        link: IDownloadableMinimum,
        name: String,
        folder: String?,
        extension: String,
        tryResume: Boolean,
        parentId: Int?,
        createNotificationCallback: (CreateNotificationMetadata) -> Unit
    ): Int {
        if (link.url.startsWith("magnet") || link.url.endsWith(".torrent")) {
            return ERROR_UNKNOWN
        }

        val relativePath = getRelativePath(folder)
        val displayName = getDisplayName(name, extension)


        fun deleteFile(): Int {
            return delete(context, name, folder, extension, parentId)
        }

        val stream = setupStream(context, name, folder, extension, tryResume)
        if (stream.errorCode != SUCCESS_STREAM) return stream.errorCode

        val resume = stream.resume!!
        val fileStream = stream.fileStream!!
        val fileLength = stream.fileLength!!

        // CONNECT
        val connection: URLConnection =
            URL(link.url.replace(" ", "%20")).openConnection() // IDK OLD PHONES BE WACK

        // SET CONNECTION SETTINGS
        connection.connectTimeout = 10000
        connection.setRequestProperty("Accept-Encoding", "identity")
        connection.setRequestProperty("user-agent", USER_AGENT)
        if (link.referer.isNotEmpty()) connection.setRequestProperty("referer", link.referer)

        // extra stuff
        connection.setRequestProperty(
            "sec-ch-ua",
            "\"Chromium\";v=\"91\", \" Not;A Brand\";v=\"99\""
        )

        connection.setRequestProperty("sec-ch-ua-mobile", "?0")
        connection.setRequestProperty("accept", "*/*")
        //   dataSource.setRequestProperty("Sec-Fetch-Site", "none") //same-site
        connection.setRequestProperty("sec-fetch-user", "?1")
        connection.setRequestProperty("sec-fetch-mode", "navigate")
        connection.setRequestProperty("sec-fetch-dest", "video")
        link.headers.entries.forEach {
            connection.setRequestProperty(it.key, it.value)
        }

        if (resume)
            connection.setRequestProperty("Range", "bytes=${fileLength}-")
        val resumeLength = (if (resume) fileLength else 0)

        // ON CONNECTION
        connection.connect()

        val contentLength = try {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) { // fuck android
                connection.contentLengthLong
            } else {
                connection.getHeaderField("content-length").toLongOrNull() ?: connection.contentLength.toLong()
            }
        } catch (e: Exception) {
            logError(e)
            0L
        }
        val bytesTotal = contentLength + resumeLength

        if (extension == "mp4" && bytesTotal < 5000000) return ERROR_TOO_SMALL_CONNECTION // DATA IS LESS THAN 5MB, SOMETHING IS WRONG

        parentId?.let {
            context.setKey(
                KEY_DOWNLOAD_INFO,
                it.toString(),
                DownloadedFileInfo(bytesTotal, relativePath, displayName)
            )
        }

        // Could use connection.contentType for mime types when creating the file,
        // however file is already created and players don't go of file type

        // https://stackoverflow.com/questions/23714383/what-are-all-the-possible-values-for-http-content-type-header
        // might receive application/octet-stream
        /*if (!connection.contentType.isNullOrEmpty() && !connection.contentType.startsWith("video")) {
            return ERROR_WRONG_CONTENT // CONTENT IS NOT VIDEO, SHOULD NEVER HAPPENED, BUT JUST IN CASE
        }*/

        // READ DATA FROM CONNECTION
        val connectionInputStream: InputStream = BufferedInputStream(connection.inputStream)
        val buffer = ByteArray(1024)
        var count: Int
        var bytesDownloaded = resumeLength

        var isPaused = false
        var isStopped = false
        var isDone = false
        var isFailed = false

        // TO NOT REUSE CODE
        fun updateNotification() {
            val type = when {
                isDone -> DownloadType.IsDone
                isStopped -> DownloadType.IsStopped
                isFailed -> DownloadType.IsFailed
                isPaused -> DownloadType.IsPaused
                else -> DownloadType.IsDownloading
            }

            parentId?.let { id ->
                try {
                    downloadStatus[id] = type
                    downloadStatusEvent.invoke(Pair(id, type))
                    downloadProgressEvent.invoke(Triple(id, bytesDownloaded, bytesTotal))
                } catch (e: Exception) {
                    // IDK MIGHT ERROR
                }
            }

            createNotificationCallback.invoke(CreateNotificationMetadata(type, bytesDownloaded, bytesTotal))
            /*createNotification(
                context,
                source,
                link.name,
                ep,
                type,
                bytesDownloaded,
                bytesTotal
            )*/
        }

        val downloadEventListener = { event: Pair<Int, DownloadActionType> ->
            if (event.first == parentId) {
                when (event.second) {
                    DownloadActionType.Pause -> {
                        isPaused = true; updateNotification()
                    }
                    DownloadActionType.Stop -> {
                        isStopped = true; updateNotification()
                        context.removeKey(KEY_RESUME_PACKAGES, event.first.toString())
                        saveQueue(context)
                    }
                    DownloadActionType.Resume -> {
                        isPaused = false; updateNotification()
                    }
                }
            }
        }

        if (parentId != null)
            downloadEvent += downloadEventListener

        // UPDATE DOWNLOAD NOTIFICATION
        val notificationCoroutine = main {
            while (true) {
                if (!isPaused) {
                    updateNotification()
                }
                for (i in 1..10) {
                    delay(100)
                }
            }
        }

        // THE REAL READ
        try {
            while (true) {
                count = connectionInputStream.read(buffer)
                if (count < 0) break
                bytesDownloaded += count
                // downloadProgressEvent.invoke(Pair(id, bytesDownloaded)) // Updates too much for any UI to keep up with
                while (isPaused) {
                    sleep(100)
                    if (isStopped) {
                        break
                    }
                }
                if (isStopped) {
                    break
                }
                fileStream.write(buffer, 0, count)
            }
        } catch (e: Exception) {
            isFailed = true
            updateNotification()
        }

        // REMOVE AND EXIT ALL
        fileStream.close()
        connectionInputStream.close()
        notificationCoroutine.cancel()

        try {
            if (parentId != null)
                downloadEvent -= downloadEventListener
        } catch (e: Exception) {
            logError(e)
        }

        try {
            parentId?.let {
                downloadStatus.remove(it)
            }
        } catch (e: Exception) {
            // IDK MIGHT ERROR
        }

        // RETURN MESSAGE
        return when {
            isFailed -> {
                parentId?.let { id -> downloadProgressEvent.invoke(Triple(id, 0, 0)) }
                ERROR_CONNECTION_ERROR
            }
            isStopped -> {
                parentId?.let { id -> downloadProgressEvent.invoke(Triple(id, 0, 0)) }
                deleteFile()
            }
            else -> {
                parentId?.let { id -> downloadProgressEvent.invoke(Triple(id, bytesDownloaded, bytesTotal)) }
                isDone = true
                updateNotification()
                SUCCESS_DOWNLOAD_DONE
            }
        }
    }

    private fun getRelativePath(folder: String?): String {
        return (Environment.DIRECTORY_DOWNLOADS + '/' + folder + '/').replace('/', File.separatorChar)
    }

    private fun getDisplayName(name: String, extension: String): String {
        return "$name.$extension"
    }

    private fun getNormalPath(relativePath: String, displayName: String): String {
        return "${Environment.getExternalStorageDirectory()}${File.separatorChar}$relativePath$displayName"
    }

    private fun delete(
        context: Context,
        name: String,
        folder: String?,
        extension: String,
        parentId: Int?,
    ): Int {
        val relativePath = getRelativePath(folder)
        val displayName = getDisplayName(name, extension)

        if (isScopedStorage()) {
            val lastContent = context.contentResolver.getExistingDownloadUriOrNullQ(relativePath, displayName)
            if (lastContent != null) {
                context.contentResolver.delete(lastContent, null, null)
            }
        } else {
            if (!File(getNormalPath(relativePath, displayName)).delete()) return ERROR_DELETING_FILE
        }
        parentId?.let {
            downloadDeleteEvent.invoke(parentId)
        }
        return SUCCESS_STOPPED
    }

    private fun downloadHLS(
        context: Context,
        link: ExtractorLink,
        name: String,
        folder: String?,
        parentId: Int?,
        startIndex: Int?,
        createNotificationCallback: (CreateNotificationMetadata) -> Unit
    ): Int {
        val extension = "mp4"
        fun logcatPrint(vararg items: Any?) {
            items.forEach {
                println("[HLS]: $it")
            }
        }

        val m3u8Helper = M3u8Helper()
        logcatPrint("initialised the HLS downloader.")

        val m3u8 = M3u8Helper.M3u8Stream(
            link.url, when (link.quality) {
                -2 -> 360
                -1 -> 480
                1 -> 720
                2 -> 1080
                else -> null
            }, mapOf("referer" to link.referer)
        )

        var realIndex = startIndex ?: 0
        val stream = setupStream(context, name, folder, extension, realIndex > 0)
        if (stream.errorCode != SUCCESS_STREAM) return stream.errorCode

        if (!stream.resume!!) realIndex = 0
        val fileLengthAdd = stream.fileLength!!
        val tsIterator = m3u8Helper.hlsYield(listOf(m3u8), realIndex)

        val relativePath = getRelativePath(folder)
        val displayName = getDisplayName(name, extension)

        val fileStream = stream.fileStream!!

        val firstTs = tsIterator.next()

        var isDone = false
        var isFailed = false
        var isPaused = false
        var bytesDownloaded = firstTs.bytes.size.toLong() + fileLengthAdd
        var tsProgress = 1L + realIndex
        val totalTs = firstTs.totalTs.toLong()

        fun deleteFile(): Int {
            return delete(context, name, folder, extension, parentId)
        }
        /*
            Most of the auto generated m3u8 out there have TS of the same size.
            And only the last TS might have a different size.

            But oh well, in cases of handmade m3u8 streams this will go all over the place ¯\_(ツ)_/¯
            So ya, this calculates an estimate of how many bytes the file is going to be.

            > (bytesDownloaded/tsProgress)*totalTs
         */

        fun updateInfo() {
            parentId?.let {
                context.setKey(
                    KEY_DOWNLOAD_INFO,
                    it.toString(),
                    DownloadedFileInfo(
                        (bytesDownloaded / tsProgress) * totalTs,
                        relativePath,
                        displayName,
                        tsProgress.toString()
                    )
                )
            }
        }
        updateInfo()

        fun updateNotification() {
            val type = when {
                isDone -> DownloadType.IsDone
                isFailed -> DownloadType.IsFailed
                isPaused -> DownloadType.IsPaused
                else -> DownloadType.IsDownloading
            }

            parentId?.let { id ->
                try {
                    downloadStatus[id] = type
                    downloadStatusEvent.invoke(Pair(id, type))
                    downloadProgressEvent.invoke(
                        Triple(
                            id,
                            bytesDownloaded,
                            (bytesDownloaded / tsProgress) * totalTs
                        )
                    )
                } catch (e: Exception) {
                    // IDK MIGHT ERROR
                }
            }

            createNotificationCallback.invoke(
                CreateNotificationMetadata(
                    type,
                    bytesDownloaded,
                    (bytesDownloaded / tsProgress) * totalTs
                )
            )
        }

        fun stopIfError(ts: M3u8Helper.HlsDownloadData): Int? {
            if (ts.errored || ts.bytes.isEmpty()) {
                val error: Int = if (!ts.errored) {
                    logcatPrint("Error: No stream was found.")
                    ERROR_UNKNOWN
                } else {
                    logcatPrint("Error: Failed to fetch data.")
                    ERROR_CONNECTION_ERROR
                }
                isFailed = true
                fileStream.close()
                deleteFile()
                updateNotification()
                return error
            }
            return null
        }

        val notificationCoroutine = main {
            while (true) {
                if (!isDone) {
                    updateNotification()
                }
                for (i in 1..10) {
                    delay(100)
                }
            }
        }

        val downloadEventListener = { event: Pair<Int, DownloadActionType> ->
            if (event.first == parentId) {
                when (event.second) {
                    DownloadActionType.Stop -> {
                        isFailed = true
                    }
                    DownloadActionType.Pause -> {
                        isPaused =
                            true  // Pausing is not supported since well...I need to know the index of the ts it was paused at
                        // it may be possible to store it in a variable, but when the app restarts it will be lost
                    }
                    DownloadActionType.Resume -> {
                        isPaused = false
                    }
                }
                updateNotification()
            }
        }

        fun closeAll() {
            try {
                if (parentId != null)
                    downloadEvent -= downloadEventListener
            } catch (e: Exception) {
                logError(e)
            }
            try {
                parentId?.let {
                    downloadStatus.remove(it)
                }
            } catch (e: Exception) {
                logError(e)
                // IDK MIGHT ERROR
            }
            notificationCoroutine.cancel()
        }

        stopIfError(firstTs).let {
            if (it != null) {
                closeAll()
                return it
            }
        }

        if (parentId != null)
            downloadEvent += downloadEventListener

        fileStream.write(firstTs.bytes)

        fun onFailed() {
            fileStream.close()
            deleteFile()
            updateNotification()
            closeAll()

        }

        for (ts in tsIterator) {
            while (isPaused) {
                if (isFailed) {
                    onFailed()
                    return SUCCESS_STOPPED
                }
                sleep(100)
            }

            if (isFailed) {
                onFailed()
                return SUCCESS_STOPPED
            }

            stopIfError(ts).let {
                if (it != null) {
                    closeAll()
                    return it
                }
            }

            fileStream.write(ts.bytes)
            tsProgress = ts.currentIndex.toLong()
            bytesDownloaded += ts.bytes.size.toLong()
            logcatPrint("Download progress ${((tsProgress.toFloat() / totalTs.toFloat()) * 100).roundToInt()}%")
            updateInfo()
        }
        isDone = true
        fileStream.close()
        updateNotification()

        closeAll()
        updateInfo()
        return SUCCESS_DOWNLOAD_DONE
    }

    private fun downloadSingleEpisode(
        context: Context,
        source: String?,
        folder: String?,
        ep: DownloadEpisodeMetadata,
        link: ExtractorLink,
        notificationCallback: (Int, Notification) -> Unit,
        tryResume: Boolean = false,
    ): Int {
        val name = sanitizeFilename(ep.name ?: "${context.getString(R.string.episode)} ${ep.episode}")

        if (link.isM3u8 || URI(link.url).path.endsWith(".m3u8")) {
            val startIndex = if (tryResume) {
                context.getKey<DownloadedFileInfo>(
                    KEY_DOWNLOAD_INFO,
                    ep.id.toString(),
                    null
                )?.extraInfo?.toIntOrNull()
            } else null
            return downloadHLS(context, link, name, folder, ep.id, startIndex) { meta ->
                main {
                    createNotification(
                        context,
                        source,
                        link.name,
                        ep,
                        meta.type,
                        meta.bytesDownloaded,
                        meta.bytesTotal,
                        notificationCallback
                    )
                }
            }
        }

        return normalSafeApiCall {
            downloadThing(context, link, name, folder, "mp4", tryResume, ep.id) { meta ->
                main {
                    createNotification(
                        context,
                        source,
                        link.name,
                        ep,
                        meta.type,
                        meta.bytesDownloaded,
                        meta.bytesTotal,
                        notificationCallback
                    )
                }
            }

        } ?: ERROR_UNKNOWN
    }

    fun downloadCheck(
        context: Context, notificationCallback: (Int, Notification) -> Unit,
    ): Int? {
        if (currentDownloads.size < maxConcurrentDownloads && downloadQueue.size > 0) {
            val pkg = downloadQueue.removeFirst()
            val item = pkg.item
            val id = item.ep.id
            if (currentDownloads.contains(id)) { // IF IT IS ALREADY DOWNLOADING, RESUME IT
                downloadEvent.invoke(Pair(id, DownloadActionType.Resume))
                /** ID needs to be returned to the work-manager to properly await notification */
                return id
            }

            currentDownloads.add(id)

            main {
                try {
                    for (index in (pkg.linkIndex ?: 0) until item.links.size) {
                        val link = item.links[index]
                        val resume = pkg.linkIndex == index

                        context.setKey(KEY_RESUME_PACKAGES, id.toString(), DownloadResumePackage(item, index))
                        val connectionResult = withContext(Dispatchers.IO) {
                            normalSafeApiCall {
                                downloadSingleEpisode(
                                    context,
                                    item.source,
                                    item.folder,
                                    item.ep,
                                    link,
                                    notificationCallback,
                                    resume
                                )
                            }
                        }
                        if (connectionResult != null && connectionResult > 0) { // SUCCESS
                            context.removeKey(KEY_RESUME_PACKAGES, id.toString())
                            break
                        }
                    }
                } catch (e: Exception) {
                    logError(e)
                } finally {
                    currentDownloads.remove(id)
                    // Because otherwise notifications will not get caught by the workmanager
                    downloadCheckUsingWorker(context)
                }
            }
        }
        return null
    }

    fun getDownloadFileInfoAndUpdateSettings(context: Context, id: Int): DownloadedFileInfoResult? {
        val res = getDownloadFileInfo(context, id)
        if (res == null) context.removeKey(KEY_DOWNLOAD_INFO, id.toString())
        return res
    }

    private fun getDownloadFileInfo(context: Context, id: Int): DownloadedFileInfoResult? {
        val info = context.getKey<DownloadedFileInfo>(KEY_DOWNLOAD_INFO, id.toString()) ?: return null

        if (isScopedStorage()) {
            val cr = context.contentResolver ?: return null
            val fileUri =
                cr.getExistingDownloadUriOrNullQ(info.relativePath, info.displayName) ?: return null
            val fileLength = cr.getFileLength(fileUri) ?: return null
            if (fileLength == 0L) return null
            return DownloadedFileInfoResult(fileLength, info.totalBytes, fileUri)
        } else {
            val normalPath = getNormalPath(info.relativePath, info.displayName)
            val dFile = File(normalPath)
            if (!dFile.exists()) return null
            return DownloadedFileInfoResult(dFile.length(), info.totalBytes, dFile.toUri())
        }
    }

    fun deleteFileAndUpdateSettings(context: Context, id: Int): Boolean {
        val success = deleteFile(context, id)
        if (success) context.removeKey(KEY_DOWNLOAD_INFO, id.toString())
        return success
    }

    private fun deleteFile(context: Context, id: Int): Boolean {
        val info = context.getKey<DownloadedFileInfo>(KEY_DOWNLOAD_INFO, id.toString()) ?: return false
        downloadEvent.invoke(Pair(id, DownloadActionType.Stop))
        downloadProgressEvent.invoke(Triple(id, 0, 0))
        downloadStatusEvent.invoke(Pair(id, DownloadType.IsStopped))
        downloadDeleteEvent.invoke(id)

        if (isScopedStorage()) {
            val cr = context.contentResolver ?: return false
            val fileUri =
                cr.getExistingDownloadUriOrNullQ(info.relativePath, info.displayName)
                    ?: return true // FILE NOT FOUND, ALREADY DELETED

            return cr.delete(fileUri, null, null) > 0 // IF DELETED ROWS IS OVER 0
        } else {
            val normalPath = getNormalPath(info.relativePath, info.displayName)
            val dFile = File(normalPath)
            if (!dFile.exists()) return true
            return dFile.delete()
        }
    }

    fun getDownloadResumePackage(context: Context, id: Int): DownloadResumePackage? {
        return context.getKey(KEY_RESUME_PACKAGES, id.toString())
    }

    fun downloadFromResume(
        context: Context,
        pkg: DownloadResumePackage,
        notificationCallback: (Int, Notification) -> Unit,
        setKey: Boolean = true
    ) {
        if (!currentDownloads.any { it == pkg.item.ep.id }) {
            if (currentDownloads.size == maxConcurrentDownloads) {
                main {
//                    showToast( // can be replaced with regular Toast
//                        context,
//                        "${pkg.item.ep.mainName}${pkg.item.ep.episode?.let { " ${context.getString(R.string.episode)} $it " } ?: " "}${
//                            context.getString(
//                                R.string.queued
//                            )
//                        }",
//                        Toast.LENGTH_SHORT
//                    )
                }
            }
            downloadQueue.addLast(pkg)
            downloadCheck(context, notificationCallback)
            if (setKey) saveQueue(context)
        } else {
            downloadEvent.invoke(
                Pair(pkg.item.ep.id, DownloadActionType.Resume)
            )
        }
    }

    private fun saveQueue(context: Context) {
        val dQueue =
            downloadQueue.toList().mapIndexed { index, any -> DownloadQueueResumePackage(index, any) }
                .toTypedArray()
        context.setKey(KEY_RESUME_QUEUE_PACKAGES, dQueue)
    }

    /*fun isMyServiceRunning(context: Context, serviceClass: Class<*>): Boolean {
        val manager = context.getSystemService(Context.ACTIVITY_SERVICE) as ActivityManager?
        for (service in manager!!.getRunningServices(Int.MAX_VALUE)) {
            if (serviceClass.name == service.service.className) {
                return true
            }
        }
        return false
    }*/

    fun downloadEpisode(
        context: Context?,
        source: String?,
        folder: String?,
        ep: DownloadEpisodeMetadata,
        links: List<ExtractorLink>,
        notificationCallback: (Int, Notification) -> Unit,
    ) {
        if (context == null) return
        if (links.isNotEmpty()) {
            downloadFromResume(
                context,
                DownloadResumePackage(DownloadItem(source, folder, ep, links), null),
                notificationCallback
            )
        }
    }

    /** Worker stuff */
    private fun startWork(context: Context, key: String) {
        val req = OneTimeWorkRequest.Builder(DownloadFileWorkManager::class.java)
            .setInputData(
                Data.Builder()
                    .putString("key", key)
                    .build()
            )
            .build()
        (WorkManager.getInstance(context)).enqueueUniqueWork(
            key,
            ExistingWorkPolicy.KEEP,
            req
        )
    }

    fun downloadCheckUsingWorker(
        context: Context,
    ) {
        startWork(context, DOWNLOAD_CHECK)
    }

    fun downloadFromResumeUsingWorker(
        context: Context,
        pkg: DownloadResumePackage,
    ) {
        val key = pkg.item.ep.id.toString()
        context.setKey(WORK_KEY_PACKAGE, key, pkg)
        startWork(context, key)
    }

    // Keys are needed to transfer the data to the worker reliably and without exceeding the data limit
    const val WORK_KEY_PACKAGE = "work_key_package"
    const val WORK_KEY_INFO = "work_key_info"

    fun downloadEpisodeUsingWorker(
        context: Context,
        source: String?,
        folder: String?,
        ep: DownloadEpisodeMetadata,
        links: List<ExtractorLink>,
    ) {
        val info = DownloadInfo(
            source, folder, ep, links
        )

        val key = info.ep.id.toString()
        context.setKey(WORK_KEY_INFO, key, info)
        startWork(context, key)
    }

    data class DownloadInfo(
        @JsonProperty("source") val source: String?,
        @JsonProperty("folder") val folder: String?,
        @JsonProperty("ep") val ep: DownloadEpisodeMetadata,
        @JsonProperty("links") val links: List<ExtractorLink>
    )
}