Long press back to go to previous position (#524)

When navigating a grid page, you can long press the back button to go
back to the previous spot.

For example, short pressing back jumps to the top, you can long press
back to go back where you were.

Dev: adds a pre-commit check to check if `DEBUG` is true anywhere since
it should only be when debugging a class.

.pre-commit-config.yaml

@@ -11,3 +11,10 @@ repos:
   hooks:
     - id: pretty-format-kotlin
       args: [ --autofix, --ktlint-version=1.4.1 ]
+- repo: local
+  hooks:
+    - id: check-debug-enabled
+      name: Check debug enabled
+      entry: val DEBUG = true
+      language: pygrep
+      files: '.+\.kt'

app/src/main/java/com/github/damontecres/stashapp/StashDataGridFragment.kt

@@ -86,6 +86,7 @@ class StashDataGridFragment :
     private var remoteButtonPaging: Boolean = true
 
     // State
+    private var previousPosition = -1
     private var selectedPosition = -1
 
     private var onBackPressedCallback: OnBackPressedCallback? = null
@@ -157,7 +158,8 @@ class StashDataGridFragment :
 
     private fun onSelectedOrJump(position: Int) {
         if (position != selectedPosition) {
-            if (DEBUG) Log.v(TAG, "gridOnItemSelected=$position")
+            if (DEBUG) Log.v(TAG, "newPosition=$position, previousPosition=$previousPosition")
+            previousPosition = selectedPosition
             selectedPosition = position
             viewModel.position = position
             positionTextView.text = formatNumber(position + 1, false)
@@ -522,6 +524,23 @@ class StashDataGridFragment :
             }
     }
 
+    override fun onKeyLongPress(
+        keyCode: Int,
+        event: KeyEvent,
+    ): Boolean {
+        if (keyCode == KeyEvent.KEYCODE_BACK) {
+            if (DEBUG) Log.d(TAG, "Long press back, maybe $selectedPosition=>$previousPosition")
+            if (previousPosition >= 0 &&
+                previousPosition != selectedPosition &&
+                requireActivity().currentFocus is StashImageCardView
+            ) {
+                jumpTo(previousPosition)
+                return true
+            }
+        }
+        return super.onKeyLongPress(keyCode, event)
+    }
+
     override fun onKeyUp(
         keyCode: Int,
         event: KeyEvent,
@@ -573,7 +592,7 @@ class StashDataGridFragment :
     companion object {
         private const val TAG = "StashDataGridFragment"
 
-        private const val DEBUG = true
+        private const val DEBUG = false
     }
 
     inner class VerticalGridItemBridgeAdapter : ItemBridgeAdapter() {