From 5921c8117df3703b5004d0abc74fd02a09ca51f6 Mon Sep 17 00:00:00 2001
From: Damyan Ivanov <dam+mobileledger@ktnx.net>
Date: Mon, 8 Feb 2021 05:58:50 +0000
Subject: [PATCH] model: ensure exactly one empty account row

also properly apply the check after removing an item. the intermediate
items.setValue(newList) is complete unnecessary

also make the check when receiving items from the database
---
 .../templates/TemplateDetailsViewModel.java   | 90 ++++++++++++++++---
 1 file changed, 76 insertions(+), 14 deletions(-)

diff --git a/app/src/main/java/net/ktnx/mobileledger/ui/templates/TemplateDetailsViewModel.java b/app/src/main/java/net/ktnx/mobileledger/ui/templates/TemplateDetailsViewModel.java
index bf1dc35a..9f87aa79 100644
--- a/app/src/main/java/net/ktnx/mobileledger/ui/templates/TemplateDetailsViewModel.java
+++ b/app/src/main/java/net/ktnx/mobileledger/ui/templates/TemplateDetailsViewModel.java
@@ -56,31 +56,94 @@ public class TemplateDetailsViewModel extends ViewModel {
     }
 
     public void resetItems() {
-        checkItemConsistency(new ArrayList<>());
+        applyList(new ArrayList<>());
     }
-    public void checkItemConsistency(List<TemplateDetailsItem> list) {
-        if (list == null)
-            list = new ArrayList<>(items.getValue());
+    public void applyList(List<TemplateDetailsItem> srcList) {
+        applyList(srcList, false);
+    }
+    public void applyList(List<TemplateDetailsItem> srcList, boolean async) {
+        boolean changes;
+        if (srcList == null) {
+            srcList = new ArrayList<>(items.getValue());
+            changes = false;
+        }
+        else
+            changes = true;
+
+        srcList = Collections.unmodifiableList(srcList);
+
+        {
+            Logger.debug("tmpl", "Considering old list");
+            for (TemplateDetailsItem item : srcList)
+                Logger.debug("tmpl", String.format(Locale.US, " id %d pos %d", item.getId(),
+                        item.getPosition()));
+        }
+
+        ArrayList<TemplateDetailsItem> newList = new ArrayList<>();
 
-        boolean changes = false;
-        if (list.size() < 1) {
+        boolean hasEmptyItem = false;
+
+        if (srcList.size() < 1) {
             final TemplateDetailsItem.Header header = TemplateDetailsItem.createHeader();
             header.setName(mDefaultPatternName);
             header.setId(0);
-            list.add(header);
+            newList.add(header);
+            changes = true;
+        }
+        else {
+            newList.add(srcList.get(0));
+        }
+
+        for (int i = 1; i < srcList.size(); i++) {
+            final TemplateDetailsItem.AccountRow accRow = srcList.get(i)
+                                                                 .asAccountRowItem();
+            if (accRow.isEmpty()) {
+                // it is normal to have two empty rows if they are at the
+                // top (position 1 and 2)
+                if (!hasEmptyItem || i < 3) {
+                    accRow.setPosition(newList.size());
+                    newList.add(accRow);
+                }
+                else
+                    changes = true; // row skipped
+
+                hasEmptyItem = true;
+            }
+            else {
+                accRow.setPosition(newList.size());
+                newList.add(accRow);
+            }
+        }
+
+        while (newList.size() < 3) {
+            final TemplateDetailsItem.AccountRow accountRow =
+                    TemplateDetailsItem.createAccountRow();
+            accountRow.setId(genItemId());
+            accountRow.setPosition(newList.size());
+            newList.add(accountRow);
             changes = true;
+            hasEmptyItem = true;
         }
 
-        while (list.size() < 3) {
+        if (!hasEmptyItem) {
             final TemplateDetailsItem.AccountRow accountRow =
                     TemplateDetailsItem.createAccountRow();
             accountRow.setId(genItemId());
-            list.add(accountRow);
+            accountRow.setPosition(newList.size());
+            newList.add(accountRow);
             changes = true;
         }
 
-        if (changes)
-            items.setValue(list);
+        if (changes) {
+            Logger.debug("tmpl", "Changes detected, applying new list");
+
+            if (async)
+                items.postValue(newList);
+            else
+                items.setValue(newList);
+        }
+        else
+            Logger.debug("tmpl", "No changes, ignoring new list");
     }
     public int genItemId() {
         return syntheticItemId.decrementAndGet();
@@ -117,7 +180,7 @@ public class TemplateDetailsViewModel extends ViewModel {
                 for (TemplateDetailsItem i : l) {
                     Logger.debug("patterns-db", "Loaded pattern item " + i);
                 }
-                items.postValue(l);
+                applyList(l, true);
                 itemsLoaded = true;
 
                 dbList.removeObserver(this);
@@ -208,7 +271,6 @@ public class TemplateDetailsViewModel extends ViewModel {
     public void removeItem(int position) {
         ArrayList<TemplateDetailsItem> newList = new ArrayList<>(items.getValue());
         newList.remove(position);
-        checkItemConsistency(newList);
-        items.setValue(newList);
+        applyList(newList);
     }
 }
\ No newline at end of file
-- 
2.39.5