Enhance financial report accuracy by including closing journals in profit and loss calculations and trial balances; add idempotency check for journal entry creation.

Repositories/AccountRepository.cs

@@ -88,7 +88,8 @@ namespace General_Ledger_Service.Repositories
         // its reversal) showed equal/duplicated figures in both columns.
         public async Task<List<TrialBalanceRowDto>> GetTrialBalanceAsync(DateOnly asOfDate)
         {
-            var totals = await GetPostedTotalsAsync(null, asOfDate);
+            // Post-closing trial balance: includes year-end closing journals (JournalType CLOSING).
+            var totals = await GetPostedTotalsAsync(null, asOfDate, includeClosing: true);
             var postableAccounts = await _context.Accounts.AsNoTracking().Where(a => a.IsPostable).ToListAsync();
 
             return [.. postableAccounts
@@ -120,7 +121,8 @@ namespace General_Ledger_Service.Repositories
             var accounts = await _context.Accounts.AsNoTracking().ToListAsync();
             var roots = accounts.Where(a => a.ParentAccountId == null && (a.AccountTypeId == 1 || a.AccountTypeId == 2 || a.AccountTypeId == 3));
             var classification = InheritTag(accounts, roots, a => a.BalanceSheetClassification);
-            var totals = await GetPostedTotalsAsync(null, asOfDate);
+            // Includes closing journals so Retained Earnings carries every closed year's profit.
+            var totals = await GetPostedTotalsAsync(null, asOfDate, includeClosing: true);
 
             return [.. accounts
                 .Where(a => a.IsPostable && classification.ContainsKey(a.AccountId) && totals.ContainsKey(a.AccountId))
@@ -141,12 +143,12 @@ namespace General_Ledger_Service.Repositories
         // pattern as cash_flow_category); ReportService groups these into the nested
         // ProfitAndLossReportDto and applies the Expense-side sign flip (Amount here is the raw,
         // unflipped credit - debit - negative for a normal debit-balance Expense account).
-        public async Task<List<ProfitAndLossLeafRowDto>> GetProfitAndLossLeafRowsAsync(DateOnly periodStart, DateOnly periodEnd)
+        public async Task<List<ProfitAndLossLeafRowDto>> GetProfitAndLossLeafRowsAsync(DateOnly periodStart, DateOnly periodEnd, bool includeClosing = false)
         {
             var accounts = await _context.Accounts.AsNoTracking().ToListAsync();
             var roots = accounts.Where(a => a.ParentAccountId == null && (a.AccountTypeId == 4 || a.AccountTypeId == 5));
             var section = InheritTag(accounts, roots, a => a.IncomeStatementSection);
-            var totals = await GetPostedTotalsAsync(periodStart, periodEnd);
+            var totals = await GetPostedTotalsAsync(periodStart, periodEnd, includeClosing);
 
             return [.. accounts
                 .Where(a => a.IsPostable && section.ContainsKey(a.AccountId) && totals.ContainsKey(a.AccountId))
@@ -254,10 +256,21 @@ namespace General_Ledger_Service.Repositories
         // Per-account base debit/credit totals over posted journal entries, optionally bounded
         // by entry date (inclusive on both ends). The sums run in the database; accounts with no
         // matching lines are simply absent from the result.
-        private async Task<Dictionary<long, (decimal Debit, decimal Credit)>> GetPostedTotalsAsync(DateOnly? from, DateOnly? to)
+        // Year-end closing journals (JournalType == ClosingJournalType) move a year's income/expense into
+        // Retained Earnings. They are excluded unless includeClosing is true, so the P&L, cash flow and
+        // similar period reports still show a closed year's own activity; the balance sheet and trial
+        // balance include them so every account's balance is complete.
+        public const string ClosingJournalType = "CLOSING";
+
+        private async Task<Dictionary<long, (decimal Debit, decimal Credit)>> GetPostedTotalsAsync(DateOnly? from, DateOnly? to, bool includeClosing = false)
         {
             var lines = _context.JournalEntryLines.Where(l => l.Journal.IsPosted);
 
+            if (!includeClosing)
+            {
+                lines = lines.Where(l => l.Journal.JournalType != ClosingJournalType);
+            }
+
             if (from.HasValue)
             {
                 lines = lines.Where(l => l.Journal.EntryDate >= from.Value);