From 2e33db48ecd6d6855f16039e0a41fe324e1a407f Mon Sep 17 00:00:00 2001
From: devyk100 <devyk100@gmail.com>
Date: Mon, 24 Feb 2025 12:13:37 +0530
Subject: [PATCH] Refactored deck iteration and empty deck check logic

---
 .../main/java/com/ichi2/anki/DeckPicker.kt    | 59 ++++---------------
 .../java/com/ichi2/libanki/sched/DeckNode.kt  |  8 ++-
 2 files changed, 19 insertions(+), 48 deletions(-)

diff --git a/AnkiDroid/src/main/java/com/ichi2/anki/DeckPicker.kt b/AnkiDroid/src/main/java/com/ichi2/anki/DeckPicker.kt
index 928d10d35c05..669be82c8d7b 100644
--- a/AnkiDroid/src/main/java/com/ichi2/anki/DeckPicker.kt
+++ b/AnkiDroid/src/main/java/com/ichi2/anki/DeckPicker.kt
@@ -2167,20 +2167,14 @@ open class DeckPicker :
             openReviewerOrStudyOptions(selectionType)
             return
         }
-        when (queryCompletedDeckCustomStudyAction(did)) {
-            CompletedDeckStatus.LEARN_AHEAD_LIMIT_REACHED,
-            CompletedDeckStatus.REGULAR_DECK_NO_MORE_CARDS_TODAY,
-            CompletedDeckStatus.DYNAMIC_DECK_NO_LIMITS_REACHED,
-            CompletedDeckStatus.DAILY_STUDY_LIMIT_REACHED,
-            -> {
-                onDeckCompleted()
-            }
-            CompletedDeckStatus.EMPTY_REGULAR_DECK -> {
-                // If the deck is empty (& has no children) then show a message saying it's empty
-                showEmptyDeckSnackbar()
-                updateUi()
-            }
+
+        if (isDeckAndSubdeckEmpty(did)) {
+            showEmptyDeckSnackbar()
+            updateUi()
+            return
         }
+
+        onDeckCompleted()
     }
 
     /**
@@ -2668,44 +2662,15 @@ open class DeckPicker :
     }
 
     /**
-     * Returns how a user can 'custom study' a deck with no more pending cards
+     * Returns if the deck and its subdecks are all empty.
      *
      * @param did The id of a deck with no pending cards to review
      */
-    private suspend fun queryCompletedDeckCustomStudyAction(did: DeckId): CompletedDeckStatus =
-        when {
-            withCol { sched.hasCardsTodayAfterStudyAheadLimit() } -> CompletedDeckStatus.LEARN_AHEAD_LIMIT_REACHED
-            withCol { sched.newDue() || sched.revDue() } -> CompletedDeckStatus.LEARN_AHEAD_LIMIT_REACHED
-            withCol { decks.isFiltered(did) } -> CompletedDeckStatus.DYNAMIC_DECK_NO_LIMITS_REACHED
-            run {
-                val node = getNodeByDid(did)
-                withCol {
-                    var allChildrenEmpty = true
-                    node.forEach { deckNode ->
-                        allChildrenEmpty = allChildrenEmpty && decks.isEmpty(deckNode.did)
-                    }
-                    allChildrenEmpty
-                }
-            } -> CompletedDeckStatus.EMPTY_REGULAR_DECK
-            else -> CompletedDeckStatus.REGULAR_DECK_NO_MORE_CARDS_TODAY
+    private suspend fun isDeckAndSubdeckEmpty(did: DeckId): Boolean {
+        val node = getNodeByDid(did)
+        return withCol {
+            node.all { decks.isEmpty(it.did) }
         }
-
-    /** Status for a deck with no current cards to review */
-    enum class CompletedDeckStatus {
-        /** No cards for today, but there would be if the user waited */
-        LEARN_AHEAD_LIMIT_REACHED,
-
-        /** No cards for today, but either the 'new' or 'review' limit was reached */
-        DAILY_STUDY_LIMIT_REACHED,
-
-        /** No cards are available, but the deck was dynamic */
-        DYNAMIC_DECK_NO_LIMITS_REACHED,
-
-        /** The deck contained no cards and had no child decks */
-        EMPTY_REGULAR_DECK,
-
-        /** The user has completed their studying for today, and there are future reviews */
-        REGULAR_DECK_NO_MORE_CARDS_TODAY,
     }
 
     override fun getApkgFileImportResultLauncher(): ActivityResultLauncher<Intent> = apkgFileImportResultLauncher
diff --git a/AnkiDroid/src/main/java/com/ichi2/libanki/sched/DeckNode.kt b/AnkiDroid/src/main/java/com/ichi2/libanki/sched/DeckNode.kt
index 6c4cd2c7d378..46746658dea7 100644
--- a/AnkiDroid/src/main/java/com/ichi2/libanki/sched/DeckNode.kt
+++ b/AnkiDroid/src/main/java/com/ichi2/libanki/sched/DeckNode.kt
@@ -25,7 +25,7 @@ data class DeckNode(
     val node: DeckTreeNode,
     val fullDeckName: String,
     val parent: WeakReference<DeckNode>? = null,
-) {
+) : Iterable<DeckNode> {
     var collapsed = node.collapsed
     val revCount = node.reviewCount
     val newCount = node.newCount
@@ -89,6 +89,12 @@ data class DeckNode(
         }
     }
 
+    override fun iterator(): Iterator<DeckNode> =
+        sequence {
+            if (node.level > 0) yield(this@DeckNode)
+            for (child in children) yieldAll(child)
+        }.iterator()
+
     /** Convert the tree into a flat list, where matching decks and the children/parents
      * are included. Decks inside collapsed decks are not considered. */
     fun filterAndFlatten(filter: CharSequence?): List<DeckNode> {