handle medium grouping at the MediaAdapter

app/src/main/kotlin/com/simplemobiletools/gallery/activities/MediaActivity.kt

@@ -319,7 +319,7 @@ class MediaActivity : SimpleActivity(), MediaAdapter.MediaOperationsListener {
         if (currAdapter == null) {
             initZoomListener()
             val fastscroller = if (config.scrollHorizontally) media_horizontal_fastscroller else media_vertical_fastscroller
-            MediaAdapter(this, media, this, mIsGetImageIntent || mIsGetVideoIntent || mIsGetAnyIntent, mAllowPickingMultiple, media_grid, fastscroller) {
+            MediaAdapter(this, media, this, mIsGetImageIntent || mIsGetVideoIntent || mIsGetAnyIntent, mAllowPickingMultiple, media_grid, fastscroller, mPath) {
                 itemClicked((it as Medium).path)
             }.apply {
                 setupZoomListener(mZoomListener)

app/src/main/kotlin/com/simplemobiletools/gallery/adapters/MediaAdapter.kt

@@ -18,12 +18,15 @@ import com.simplemobiletools.commons.views.MyRecyclerView
 import com.simplemobiletools.gallery.R
 import com.simplemobiletools.gallery.dialogs.DeleteWithRememberDialog
 import com.simplemobiletools.gallery.extensions.*
+import com.simplemobiletools.gallery.helpers.GROUP_BY_NONE
 import com.simplemobiletools.gallery.helpers.VIEW_TYPE_LIST
 import com.simplemobiletools.gallery.models.Medium
 import kotlinx.android.synthetic.main.photo_video_item_grid.view.*
+import java.util.HashMap
+import kotlin.collections.ArrayList
 
 class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Medium>, val listener: MediaOperationsListener?, val isAGetIntent: Boolean,
-                   val allowMultiplePicks: Boolean, recyclerView: MyRecyclerView, fastScroller: FastScroller? = null,
+                   val allowMultiplePicks: Boolean, recyclerView: MyRecyclerView, fastScroller: FastScroller? = null, val path: String,
                    itemClick: (Any) -> Unit) : MyRecyclerViewAdapter(activity, recyclerView, fastScroller, itemClick) {
 
     private val INSTANT_LOAD_DURATION = 2000L
@@ -36,6 +39,7 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Medium>,
     private var delayHandler = Handler(Looper.getMainLooper())
     private var currentMediaHash = media.hashCode()
     private val hasOTGConnected = activity.hasOTGConnected()
+    private var mediumGroups = HashMap<String, ArrayList<Medium>>()
 
     private var scrollHorizontally = config.scrollHorizontally
     private var animateGifs = config.animateGifs
@@ -44,6 +48,7 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Medium>,
 
     init {
         setupDragListener(true)
+        groupMedia()
         enableInstantLoad()
     }
 
@@ -289,6 +294,7 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Medium>,
             currentMediaHash = newMedia.hashCode()
             Handler().postDelayed({
                 media = newMedia
+                groupMedia()
                 enableInstantLoad()
                 notifyDataSetChanged()
                 finishActMode()
@@ -325,6 +331,21 @@ class MediaAdapter(activity: BaseSimpleActivity, var media: MutableList<Medium>,
         }, INSTANT_LOAD_DURATION)
     }
 
+    private fun groupMedia() {
+        val grouping = activity.config.getFolderGrouping(path)
+        if (grouping and GROUP_BY_NONE != 0) {
+            return
+        }
+
+        media.forEach {
+            val key = it.getGroupingKey(grouping)
+            if (!mediumGroups.containsKey(key)) {
+                mediumGroups[key] = ArrayList()
+            }
+            mediumGroups[key]!!.add(it)
+        }
+    }
+
     private fun setupView(view: View, medium: Medium) {
         view.apply {
             play_outline.beVisibleIf(medium.isVideo())

app/src/main/kotlin/com/simplemobiletools/gallery/dialogs/PickMediumDialog.kt

@@ -62,7 +62,7 @@ class PickMediumDialog(val activity: BaseSimpleActivity, val path: String, val c
             return
 
         shownMedia = media
-        val adapter = MediaAdapter(activity, media, null, true, false, view.media_grid) {
+        val adapter = MediaAdapter(activity, media, null, true, false, view.media_grid, null, path) {
             callback((it as Medium).path)
             dialog.dismiss()
         }

app/src/main/kotlin/com/simplemobiletools/gallery/models/Medium.kt

@@ -6,14 +6,12 @@ import android.arch.persistence.room.Index
 import android.arch.persistence.room.PrimaryKey
 import com.simplemobiletools.commons.extensions.formatDate
 import com.simplemobiletools.commons.extensions.formatSize
+import com.simplemobiletools.commons.extensions.getFilenameExtension
 import com.simplemobiletools.commons.helpers.SORT_BY_DATE_MODIFIED
 import com.simplemobiletools.commons.helpers.SORT_BY_NAME
 import com.simplemobiletools.commons.helpers.SORT_BY_PATH
 import com.simplemobiletools.commons.helpers.SORT_BY_SIZE
-import com.simplemobiletools.gallery.helpers.TYPE_GIFS
+import com.simplemobiletools.gallery.helpers.*
-import com.simplemobiletools.gallery.helpers.TYPE_IMAGES
-import com.simplemobiletools.gallery.helpers.TYPE_RAWS
-import com.simplemobiletools.gallery.helpers.TYPE_VIDEOS
 import java.io.Serializable
 
 @Entity(tableName = "media", indices = [(Index(value = "full_path", unique = true))])
@@ -47,4 +45,15 @@ data class Medium(
         sorting and SORT_BY_DATE_MODIFIED != 0 -> modified.formatDate()
         else -> taken.formatDate()
     }
+
+    fun getGroupingKey(groupBy: Int): String {
+        return when {
+            groupBy and GROUP_BY_LAST_MODIFIED != 0 -> modified.toString()
+            groupBy and GROUP_BY_DATE_TAKEN != 0 -> taken.toString()
+            groupBy and GROUP_BY_FILE_TYPE != 0 -> type.toString()
+            groupBy and GROUP_BY_EXTENSION != 0 -> name.getFilenameExtension().toLowerCase()
+            groupBy and GROUP_BY_FOLDER != 0 -> parentPath
+            else -> ""
+        }
+    }
 }