From 7d64f366b7ea5df7ac0119900c97018174735f48 Mon Sep 17 00:00:00 2001
From: David Allison <62114487+david-allison@users.noreply.github.com>
Date: Sun, 24 Dec 2023 13:32:21 +0000
Subject: [PATCH] refactor: Card Browser - Preview

---
 .../main/java/com/ichi2/anki/CardBrowser.kt   | 19 ++++---------------
 .../anki/browser/CardBrowserViewModel.kt      | 19 +++++++++++++++++++
 .../java/com/ichi2/anki/CardBrowserTest.kt    | 12 ++++++------
 3 files changed, 29 insertions(+), 21 deletions(-)

diff --git a/AnkiDroid/src/main/java/com/ichi2/anki/CardBrowser.kt b/AnkiDroid/src/main/java/com/ichi2/anki/CardBrowser.kt
index d5e21fa2cca3..1c1e2db094c2 100644
--- a/AnkiDroid/src/main/java/com/ichi2/anki/CardBrowser.kt
+++ b/AnkiDroid/src/main/java/com/ichi2/anki/CardBrowser.kt
@@ -1192,21 +1192,10 @@ open class CardBrowser :
         )
     }
 
-    protected fun onPreview() {
-        onPreviewCardsActivityResult.launch(previewIntent)
-    } // Preview all cards, starting from the one that is currently selected
-
-    // Multiple cards have been explicitly selected, so preview only those cards
-    @get:VisibleForTesting
-    val previewIntent: Intent
-        get() = if (isInMultiSelectMode && viewModel.selectedRowCount() > 1) {
-            // Multiple cards have been explicitly selected, so preview only those cards
-            getPreviewIntent(0, selectedCardIds.toLongArray())
-        } else {
-            // Preview all cards, starting from the one that is currently selected
-            val startIndex = viewModel.selectedRows.firstOrNull()?.position ?: 0
-            getPreviewIntent(startIndex, viewModel.allCardIds)
-        }
+    private fun onPreview() {
+        val intentData = viewModel.previewIntentData
+        onPreviewCardsActivityResult.launch(getPreviewIntent(intentData.index, intentData.cardList))
+    }
 
     private fun getPreviewIntent(index: Int, selectedCardIds: LongArray): Intent {
         return if (sharedPrefs().getBoolean("new_previewer", false)) {
diff --git a/AnkiDroid/src/main/java/com/ichi2/anki/browser/CardBrowserViewModel.kt b/AnkiDroid/src/main/java/com/ichi2/anki/browser/CardBrowserViewModel.kt
index 59d2a74d96a4..3b616fa6a9bb 100644
--- a/AnkiDroid/src/main/java/com/ichi2/anki/browser/CardBrowserViewModel.kt
+++ b/AnkiDroid/src/main/java/com/ichi2/anki/browser/CardBrowserViewModel.kt
@@ -27,6 +27,7 @@ import com.ichi2.anki.CardBrowser
 import com.ichi2.anki.CollectionManager.withCol
 import com.ichi2.anki.DeckSpinnerSelection.Companion.ALL_DECKS_ID
 import com.ichi2.anki.Flag
+import com.ichi2.anki.PreviewDestination
 import com.ichi2.anki.R
 import com.ichi2.anki.dialogs.ExportDialogParams
 import com.ichi2.anki.export.ExportType
@@ -459,6 +460,24 @@ class CardBrowserViewModel(
         setFilterQuery(sb.toString())
     }
 
+    /** Previewing */
+
+    val previewIntentData: PreviewDestination
+        get() = if (selectedRowCount() > 1) {
+            // Multiple cards have been explicitly selected, so preview only those cards
+            PreviewDestination(index = 0, cardList = selectedCardIds.toLongArray())
+        } else {
+            // Preview all cards, starting from the one that is currently selected
+            val startIndex = indexOfFirstCheckedCard() ?: 0
+            PreviewDestination(startIndex, allCardIds)
+        }
+
+    /** @return the index of the first checked card in [cards], or `null` if no cards are checked */
+    private fun indexOfFirstCheckedCard(): Int? {
+        val idToFind = selectedRows.firstOrNull()?.id ?: return null
+        return allCardIds.indexOf(idToFind)
+    }
+
     companion object {
         const val DISPLAY_COLUMN_1_KEY = "cardBrowserColumn1"
         const val DISPLAY_COLUMN_2_KEY = "cardBrowserColumn2"
diff --git a/AnkiDroid/src/test/java/com/ichi2/anki/CardBrowserTest.kt b/AnkiDroid/src/test/java/com/ichi2/anki/CardBrowserTest.kt
index e5894220192a..502f5d260256 100644
--- a/AnkiDroid/src/test/java/com/ichi2/anki/CardBrowserTest.kt
+++ b/AnkiDroid/src/test/java/com/ichi2/anki/CardBrowserTest.kt
@@ -435,11 +435,11 @@ class CardBrowserTest : RobolectricTest() {
         assertThat(b.getPropertiesForCardId(cid2).position, equalTo(1))
 
         b.selectRowsWithPositions(0)
-        val previewIntent = b.previewIntent
-        assertThat("before: index", previewIntent.getIntExtra("index", -100), equalTo(0))
+        val previewIntent = b.viewModel.previewIntentData
+        assertThat("before: index", previewIntent.index, equalTo(0))
         assertThat(
             "before: cards",
-            previewIntent.getLongArrayExtra("cardList"),
+            previewIntent.cardList,
             equalTo(longArrayOf(cid1, cid2))
         )
 
@@ -450,11 +450,11 @@ class CardBrowserTest : RobolectricTest() {
         assertThat(b.getPropertiesForCardId(cid2).position, equalTo(0))
 
         b.replaceSelectionWith(intArrayOf(0))
-        val intentAfterReverse = b.previewIntent
-        assertThat("after: index", intentAfterReverse.getIntExtra("index", -100), equalTo(0))
+        val intentAfterReverse = b.viewModel.previewIntentData
+        assertThat("after: index", intentAfterReverse.index, equalTo(0))
         assertThat(
             "after: cards",
-            intentAfterReverse.getLongArrayExtra("cardList"),
+            intentAfterReverse.cardList,
             equalTo(longArrayOf(cid2, cid1))
         )
     }