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app/src/main/java/xyz/quaver/pupil/util/DownloadManager.kt

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+/*
+ *     Pupil, Hitomi.la viewer for Android
+ *     Copyright (C) 2021  tom5079
+ *
+ *     This program is free software: you can redistribute it and/or modify
+ *     it under the terms of the GNU General Public License as published by
+ *     the Free Software Foundation, either version 3 of the License, or
+ *     (at your option) any later version.
+ *
+ *     This program is distributed in the hope that it will be useful,
+ *     but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *     GNU General Public License for more details.
+ *
+ *     You should have received a copy of the GNU General Public License
+ *     along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package xyz.quaver.pupil.util
+
+import android.content.Context
+import android.content.ContextWrapper
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.async
+import kotlinx.coroutines.launch
+import kotlinx.serialization.decodeFromString
+import kotlinx.serialization.encodeToString
+import kotlinx.serialization.json.Json
+import org.kodein.di.DIAware
+import org.kodein.di.android.di
+import org.kodein.di.instance
+import xyz.quaver.io.FileX
+import xyz.quaver.io.util.*
+import xyz.quaver.pupil.sources.AnySource
+
+class DownloadManager constructor(context: Context) : ContextWrapper(context), DIAware {
+
+    override val di by di(context)
+
+    private val defaultDownloadFolder = FileX(this, getExternalFilesDir(null)!!)
+
+    val downloadFolder: FileX
+        get() = {
+            kotlin.runCatching {
+                FileX(this, Preferences.get<String>("download_folder"))
+            }.getOrElse {
+                Preferences["download_folder"] = defaultDownloadFolder.uri.toString()
+                defaultDownloadFolder
+            }
+        }.invoke()
+
+    private var prevDownloadFolder: FileX? = null
+    private var downloadFolderMapInstance: MutableMap<String, String>? = null
+    private val downloadFolderMap: MutableMap<String, String>
+        @Synchronized
+        get() {
+            if (prevDownloadFolder != downloadFolder) {
+                prevDownloadFolder = downloadFolder
+                downloadFolderMapInstance = {
+                    val file = downloadFolder.getChild(".download")
+
+                    val data = if (file.exists())
+                        kotlin.runCatching {
+                            file.readText()?.let { Json.decodeFromString<MutableMap<String, String>>(it) }
+                        }.onFailure { file.delete() }.getOrNull()
+                    else
+                        null
+
+                    data ?: {
+                        file.createNewFile()
+                        mutableMapOf<String, String>()
+                    }.invoke()
+                }.invoke()
+            }
+
+            return downloadFolderMapInstance ?: mutableMapOf()
+        }
+
+    @Synchronized
+    fun getDownloadFolder(source: String, itemID: String): FileX? =
+        downloadFolderMap["$source-$itemID"]?.let { downloadFolder.getChild(it) }
+
+    @Synchronized
+    fun download(source: String, itemID: String) = CoroutineScope(Dispatchers.IO).launch {
+        val source: AnySource by instance(tag = source)
+        val info = async { source.info(itemID) }
+        val images = async { source.images(itemID) }
+
+        val name = info.await().formatDownloadFolder()
+
+        val folder = downloadFolder.getChild("$source/$name")
+
+        if (folder.exists())
+            return@launch
+
+        folder.mkdir()
+
+        downloadFolderMap["$source/$itemID"] = folder.name
+
+        downloadFolder.getChild(".download").let { if (!it.exists()) it.createNewFile() }
+        downloadFolder.getChild(".download").writeText(Json.encodeToString(downloadFolderMap))
+    }
+
+    @Synchronized
+    fun delete(source: String, itemID: String) {
+        downloadFolderMap["$source/$itemID"]?.let {
+            kotlin.runCatching {
+                downloadFolder.getChild(it).deleteRecursively()
+                downloadFolderMap.remove("$source/$itemID")
+
+                downloadFolder.getChild(".download").let { if (!it.exists()) it.createNewFile() }
+                downloadFolder.getChild(".download").writeText(Json.encodeToString(downloadFolderMap))
+            }
+        }
+    }
+}