[add] Implement Bilibili style

app/src/main/java/com/acitelight/aether/service/RecentManager.kt

@@ -0,0 +1,94 @@
+package com.acitelight.aether.service
+
+import android.content.Context
+import com.acitelight.aether.model.Video
+import com.acitelight.aether.model.VideoQueryIndex
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.sync.Mutex
+import kotlinx.coroutines.sync.withLock
+import kotlinx.coroutines.withContext
+import kotlinx.serialization.json.*
+import java.io.File
+import java.io.FileNotFoundException
+import java.io.IOException
+
+object RecentManager
+{
+    private val mutex = Mutex()
+
+    suspend fun readFile(context: Context, filename: String): String {
+        return withContext(Dispatchers.IO) {
+            try {
+                val file = File(context.filesDir, filename)
+                val content = file.readText()
+                content
+            } catch (e: FileNotFoundException) {
+                "[]"
+            } catch (e: IOException) {
+                "[]"
+            }
+        }
+    }
+
+    suspend fun writeFile(context: Context, filename: String, content: String) {
+        withContext(Dispatchers.IO) {
+            try {
+                val file = File(context.filesDir, filename)
+                file.writeText(content)
+
+            } catch (e: IOException) {
+                e.printStackTrace()
+            }
+        }
+    }
+
+    suspend fun Query(context: Context): List<VideoQueryIndex>
+    {
+        val content = readFile(context, "recent.json")
+        try{
+            val r = Json.decodeFromString<List<VideoQueryIndex>>(content)
+
+            _recent.value = r.map{
+                MediaManager.queryVideo(it.klass, it.id)
+            }
+            return r
+        }catch (e: Exception)
+        {
+            print(e.message)
+        }
+
+        return listOf()
+    }
+
+    suspend fun Push(context: Context, video: VideoQueryIndex)
+    {
+        mutex.withLock{
+            val content = readFile(context, "recent.json")
+            var o = Json.decodeFromString<List<VideoQueryIndex>>(content).toMutableList();
+
+            if(o.contains(video))
+            {
+                val temp = o[0]
+                val index = o.indexOf(video)
+                o[0] = o[index]
+                o[index] = temp
+            }
+            else
+            {
+                o.add(0, video)
+            }
+
+            if(o.size >= 21)
+                o.removeAt(o.size - 1)
+            _recent.value = o.map{
+                MediaManager.queryVideo(it.klass, it.id)
+            }
+            writeFile(context, "recent.json", Json.encodeToString(o))
+        }
+    }
+
+    private val _recent = MutableStateFlow<List<Video>>(emptyList())
+    val recent: StateFlow<List<Video>> = _recent
+}