todo on Analyzer.Add complexity vs retaining existing behavior

todo.yaml

@@ -19,11 +19,21 @@ todo:
     or latest?
   - analyzer.go:Analyzer:Add should dedupe transactions added, but transactions.go:FromFile
     will load duplicate transactions from json file so hmmmm
-  - analyzer.go:Analzyer:Add dedupes each transaction, which is O(n**2) to compare
+  - todo: analyzer.go:Analzyer:Add dedupes each transaction, which is O(n**2)
-    each input with each existing entry
+    details: |
+      * BUT there's no indicator whether order of the array matters, so it's unsafe for me to sort/heapify that stuff
+      * OR I can store a second copy of all entries in a map, but that risks drift syncing the two
+      * SO I could create a UniqueTransactions struct {
+          transactions []Transaction
+          dedupes map[Transaction]struct{}
+        }
+        but that's just doubling RAM usage in a thing that sounds like it could scale infinitely over time
+        SO I could do a [hash(Transaction)][]*Transaction and compare just a subset. Because it's in RAM and computed live, the hash cardinality could be changed on any release
+        <------------------ if I have time, do this
   - analyzer.go:Analyzer:Add dedupes but what is a duplicate transaction? Transactions
     can be pending and then later disappear to have their date updated OR be like
     pre-charges on credit cards that later disappear
+  - analyzer.go:Analyzer:Add is not concurrency-safe
 scheduled: []
 done:
 - todo: hello world
@@ -533,3 +543,28 @@ done:
   - analyzer.go:Analyzer:Add should dedupe transactions added, but transactions.go:FromFile
     will load duplicate transactions from json file so hmmmm
   ts: Sun Oct 15 11:44:18 MDT 2023
+- todo: go test
+  subtasks:
+  - TestAnalyzer_DuplicatesExcluded
+  - TestAnalyzer_GroupByCategory
+  - TestAnalyzer_BigSpendersReport
+  - TestAnalyzer_TransactionsFromURLs
+  - TestAnalyzer_TransactionsFromURLsConcurrent
+  - amount.go:Rounded probably does NOT handle float precision well... it is float64
+    tho...
+  - my `go mod tidy` actually cleared `go.mod` file, probably weird localhost backwards
+    compatilble stuff
+  - transaction.go:Transaction:String not clear if FormatUSD or amount currency should
+    not be changed, or even what currency Amount is
+  - transaction.go:Transaction:Sum again doesnt care about Amount currency or vendor/vendee
+    drift
+  - analyzer.go:Analyzer:LargestTransaction doesn't specify how to break ties; stable
+    or latest?
+  - analyzer.go:Analyzer:Add should dedupe transactions added, but transactions.go:FromFile
+    will load duplicate transactions from json file so hmmmm
+  - analyzer.go:Analzyer:Add dedupes each transaction, which is O(n**2) to compare
+    each input with each existing entry
+  - analyzer.go:Analyzer:Add dedupes but what is a duplicate transaction? Transactions
+    can be pending and then later disappear to have their date updated OR be like
+    pre-charges on credit cards that later disappear
+  ts: Sun Oct 15 11:49:32 MDT 2023