feat(gcash): complete Phase 4 dual-float ledger, customizable fee scheduler, rate card PDF, and receipt OCR

frontend/lib/core/database/app_database.dart

@@ -26,6 +26,26 @@ part 'app_database.g.dart';
   GcashFeeConfig,
   SyncQueue,
 ])
+class DualFloatBalance {
+  final double gcashFloat;
+  final double cashDrawer;
+  final double totalFeesEarned;
+  final int totalTransactions;
+  final int cashInCount;
+  final int cashOutCount;
+  final int storePaymentCount;
+
+  const DualFloatBalance({
+    required this.gcashFloat,
+    required this.cashDrawer,
+    required this.totalFeesEarned,
+    required this.totalTransactions,
+    required this.cashInCount,
+    required this.cashOutCount,
+    required this.storePaymentCount,
+  });
+}
+
 class AppDatabase extends _$AppDatabase {
   AppDatabase() : super(_openConnection());
 
@@ -472,7 +492,7 @@ class AppDatabase extends _$AppDatabase {
   }
 
   // --------------------------------------------------------------------------
-  // GCASH LEDGER OPERATIONS
+  // GCASH LEDGER OPERATIONS & DUAL-FLOAT ENGINE
   // --------------------------------------------------------------------------
 
   /// Watch GCash transaction history
@@ -480,8 +500,18 @@ class AppDatabase extends _$AppDatabase {
     return (select(gcashLedger)..orderBy([(g) => OrderingTerm.desc(g.timestamp)])).watch();
   }
 
+  /// Check if a GCash reference number has already been logged (anti-fraud/scam check)
+  Future<bool> isReferenceNumberUsed(String refNo) async {
+    final clean = refNo.replaceAll(RegExp(r'\s+'), '').trim();
+    if (clean.isEmpty) return false;
+    final all = await select(gcashLedger).get();
+    return all.any((t) =>
+        t.referenceNumber != null &&
+        t.referenceNumber!.replaceAll(RegExp(r'\s+'), '').trim().toLowerCase() == clean.toLowerCase());
+  }
+
   /// Record GCash cash-in / cash-out with convenience fee
-  Future<void> recordGcash({
+  Future<String> recordGcash({
     required String transactionType,
     required double amount,
     required double feeCharged,
@@ -523,6 +553,204 @@ class AppDatabase extends _$AppDatabase {
         },
       );
     });
+
+    return gcashId;
+  }
+
+  /// Alias for recordGcash to support flexible naming
+  Future<String> recordGcashEntry({
+    required String transactionType,
+    required double amount,
+    required double feeCharged,
+    String? referenceNumber,
+    String? customerName,
+    String? customerPhone,
+    String? notes,
+  }) => recordGcash(
+    transactionType: transactionType,
+    amount: amount,
+    feeCharged: feeCharged,
+    referenceNumber: referenceNumber,
+    customerName: customerName,
+    customerPhone: customerPhone,
+    notes: notes,
+  );
+
+  /// Watch customizable fee schedule brackets
+  Stream<List<GcashFeeBracket>> watchFeeBrackets() {
+    return (select(gcashFeeConfig)..orderBy([(b) => OrderingTerm.asc(b.minAmount)])).watch();
+  }
+
+  /// Get current fee brackets
+  Future<List<GcashFeeBracket>> getFeeBrackets() {
+    return (select(gcashFeeConfig)..orderBy([(b) => OrderingTerm.asc(b.minAmount)])).get();
+  }
+
+  /// Seed default Philippine sari-sari store fee schedule if empty
+  Future<void> seedDefaultFeeBrackets() async {
+    final existing = await select(gcashFeeConfig).get();
+    if (existing.isNotEmpty) return;
+
+    final defaultBrackets = [
+      GcashFeeConfigCompanion.insert(
+        id: _uuid.v4(),
+        minAmount: 1.0,
+        maxAmount: 500.0,
+        fixedFee: const Value(10.0),
+        percentageFee: const Value(0.0),
+      ),
+      GcashFeeConfigCompanion.insert(
+        id: _uuid.v4(),
+        minAmount: 501.0,
+        maxAmount: 1000.0,
+        fixedFee: const Value(15.0),
+        percentageFee: const Value(0.0),
+      ),
+      GcashFeeConfigCompanion.insert(
+        id: _uuid.v4(),
+        minAmount: 1001.0,
+        maxAmount: 1500.0,
+        fixedFee: const Value(20.0),
+        percentageFee: const Value(0.0),
+      ),
+      GcashFeeConfigCompanion.insert(
+        id: _uuid.v4(),
+        minAmount: 1501.0,
+        maxAmount: 2000.0,
+        fixedFee: const Value(25.0),
+        percentageFee: const Value(0.0),
+      ),
+      GcashFeeConfigCompanion.insert(
+        id: _uuid.v4(),
+        minAmount: 2001.0,
+        maxAmount: 3000.0,
+        fixedFee: const Value(35.0),
+        percentageFee: const Value(0.0),
+      ),
+      GcashFeeConfigCompanion.insert(
+        id: _uuid.v4(),
+        minAmount: 3001.0,
+        maxAmount: 5000.0,
+        fixedFee: const Value(50.0),
+        percentageFee: const Value(0.0),
+      ),
+      GcashFeeConfigCompanion.insert(
+        id: _uuid.v4(),
+        minAmount: 5001.0,
+        maxAmount: 10000.0,
+        fixedFee: const Value(0.0),
+        percentageFee: const Value(1.5),
+      ),
+      GcashFeeConfigCompanion.insert(
+        id: _uuid.v4(),
+        minAmount: 10001.0,
+        maxAmount: 50000.0,
+        fixedFee: const Value(0.0),
+        percentageFee: const Value(2.0),
+      ),
+    ];
+
+    for (final bracket in defaultBrackets) {
+      await into(gcashFeeConfig).insert(bracket);
+    }
+  }
+
+  /// Upsert a fee bracket with cloud sync queueing
+  Future<void> saveFeeBracket(GcashFeeConfigCompanion bracket) async {
+    await into(gcashFeeConfig).insertOnConflictUpdate(bracket);
+    await _enqueueSync(
+      entityTable: 'gcash_fee_config',
+      entityId: bracket.id.value,
+      operation: 'UPSERT',
+      payload: {
+        'id': bracket.id.value,
+        'minAmount': bracket.minAmount.value,
+        'maxAmount': bracket.maxAmount.value,
+        'fixedFee': bracket.fixedFee.present ? bracket.fixedFee.value : 0.0,
+        'percentageFee': bracket.percentageFee.present ? bracket.percentageFee.value : 0.0,
+      },
+    );
+  }
+
+  /// Delete a fee bracket with sync queueing
+  Future<void> deleteFeeBracket(String id) async {
+    await (delete(gcashFeeConfig)..where((b) => b.id.equals(id))).go();
+    await _enqueueSync(
+      entityTable: 'gcash_fee_config',
+      entityId: id,
+      operation: 'DELETE',
+      payload: {'id': id},
+    );
+  }
+
+  /// Calculate convenience fee for a given amount using active brackets
+  Future<double> calculateGcashFee(double amount) async {
+    final brackets = await getFeeBrackets();
+    for (final b in brackets) {
+      if (amount >= b.minAmount && amount <= b.maxAmount) {
+        if (b.percentageFee > 0) {
+          return (amount * (b.percentageFee / 100.0));
+        }
+        return b.fixedFee;
+      }
+    }
+    // Default fallback brackets if table is empty
+    if (amount <= 500) return 10.0;
+    if (amount <= 1000) return 15.0;
+    if (amount <= 1500) return 20.0;
+    if (amount <= 2000) return 25.0;
+    if (amount <= 3000) return 35.0;
+    if (amount <= 5000) return 50.0;
+    return (amount * 0.015);
+  }
+
+  /// Watch real-time dual-float balances (GCash E-Wallet vs Physical Cash Drawer)
+  Stream<DualFloatBalance> watchDualFloatBalance({
+    double baseCash = 5000.0,
+    double baseGcash = 10000.0,
+  }) {
+    return watchGcashTransactions().asyncMap((txList) async {
+      final cashSales = await (select(sales)..where((s) => s.paymentMethod.equals('CASH'))).get();
+
+      double gcash = baseGcash;
+      double cash = baseCash;
+      double fees = 0.0;
+      int cashIn = 0;
+      int cashOut = 0;
+      int storePay = 0;
+
+      for (final tx in txList) {
+        fees += tx.feeCharged;
+        if (tx.transactionType == 'CASH_IN') {
+          cashIn++;
+          gcash -= tx.amount; // Store sent GCash
+          cash += (tx.amount + tx.feeCharged); // Store received cash + fee
+        } else if (tx.transactionType == 'CASH_OUT') {
+          cashOut++;
+          gcash += tx.amount; // Store received GCash
+          cash -= (tx.amount - tx.feeCharged); // Cash given to customer minus fee
+        } else if (tx.transactionType == 'STORE_PAYMENT') {
+          storePay++;
+          gcash += tx.amount; // Direct store sale paid to GCash
+        } else if (tx.transactionType == 'FLOAT_ADJUSTMENT') {
+          gcash += tx.amount;
+        }
+      }
+
+      for (final s in cashSales) {
+        cash += s.totalAmount;
+      }
+
+      return DualFloatBalance(
+        gcashFloat: gcash,
+        cashDrawer: cash,
+        totalFeesEarned: fees,
+        totalTransactions: txList.length,
+        cashInCount: cashIn,
+        cashOutCount: cashOut,
+        storePaymentCount: storePay,
+      );
+    });
   }
 
   // --------------------------------------------------------------------------

frontend/lib/features/gcash/gcash_receipt_ocr_service.dart

@@ -0,0 +1,92 @@
+import 'dart:io';
+import 'package:flutter/foundation.dart';
+import 'package:google_mlkit_text_recognition/google_mlkit_text_recognition.dart';
+
+class GcashOcrResult {
+  final String? referenceNumber;
+  final double? amount;
+  final String rawText;
+  final bool isSuccess;
+
+  const GcashOcrResult({
+    this.referenceNumber,
+    this.amount,
+    required this.rawText,
+    required this.isSuccess,
+  });
+}
+
+class GcashReceiptOcrService {
+  /// Primary regex for extracting 13-digit GCash reference number
+  /// Handles spaced formats: '1002 481 029412', '0021 482 910245', or solid '1002481029412'
+  static final RegExp refRegex = RegExp(
+    r'(?:Ref(?:\.|erence)?(?:\s*No\.?)?[:\s]*|Reference\s*ID[:\s]*)?([0-9]{4}[\s\-]?[0-9]{3,4}[\s\-]?[0-9]{5,6}|[0-9]{13})',
+    caseSensitive: false,
+  );
+
+  /// Secondary regex for extracting Peso amounts: 'PHP 500.00', 'P 1,000.00', 'Php500'
+  static final RegExp amountRegex = RegExp(
+    r'(?:PHP|Php|P|₱)\s*([0-9]{1,3}(?:,[0-9]{3})*(?:\.[0-9]{2})?)',
+    caseSensitive: false,
+  );
+
+  /// Parse text directly using regex slotting
+  static GcashOcrResult parseRawText(String text) {
+    String? foundRef;
+    double? foundAmount;
+
+    // Search for 13-digit reference number
+    final refMatches = refRegex.allMatches(text);
+    for (final match in refMatches) {
+      final rawMatch = match.group(1) ?? match.group(0);
+      if (rawMatch != null) {
+        final digitsOnly = rawMatch.replaceAll(RegExp(r'[^0-9]'), '');
+        if (digitsOnly.length == 13) {
+          foundRef = digitsOnly;
+          break;
+        }
+      }
+    }
+
+    // Search for Amount
+    final amountMatch = amountRegex.firstMatch(text);
+    if (amountMatch != null) {
+      final amtStr = amountMatch.group(1)?.replaceAll(',', '');
+      if (amtStr != null) {
+        foundAmount = double.tryParse(amtStr);
+      }
+    }
+
+    return GcashOcrResult(
+      referenceNumber: foundRef,
+      amount: foundAmount,
+      rawText: text,
+      isSuccess: foundRef != null,
+    );
+  }
+
+  /// Process an image file from camera / gallery using Google ML Kit
+  static Future<GcashOcrResult> processReceiptImage(String imagePath) async {
+    // Fallback on platforms without Google ML Kit support (e.g. desktop/web during tests)
+    if (kIsWeb || (!Platform.isAndroid && !Platform.isIOS)) {
+      return const GcashOcrResult(
+        rawText: 'MLKit OCR not supported on desktop/web platform. Use manual entry or mobile device.',
+        isSuccess: false,
+      );
+    }
+
+    try {
+      final inputImage = InputImage.fromFilePath(imagePath);
+      final textRecognizer = TextRecognizer(script: TextRecognitionScript.latin);
+      final RecognizedText recognizedText = await textRecognizer.processImage(inputImage);
+      await textRecognizer.close();
+
+      return parseRawText(recognizedText.text);
+    } catch (e) {
+      return GcashOcrResult(
+        rawText: 'Error performing OCR: $e',
+        isSuccess: false,
+      );
+    }
+  }
+}

frontend/lib/features/gcash/rate_card_pdf_service.dart

@@ -0,0 +1,303 @@
+import 'dart:typed_data';
+import 'package:pdf/pdf.dart';
+import 'package:pdf/widgets.dart' as pw;
+import 'package:printing/printing.dart';
+import '../../core/database/app_database.dart';
+
+enum RateCardFormat {
+  a4Sheet,
+  a5HalfSheet,
+  posThermal80mm,
+  posThermal58mm,
+}
+
+class RateCardPdfService {
+  /// Generate printable rate card PDF bytes
+  static Future<Uint8List> generateRateCardPdf({
+    required String storeName,
+    required List<GcashFeeBracket> brackets,
+    RateCardFormat format = RateCardFormat.a4Sheet,
+    String? gcashNumber,
+  }) async {
+    final pdf = pw.Document();
+
+    final PdfPageFormat pageFormat;
+    switch (format) {
+      case RateCardFormat.a4Sheet:
+        pageFormat = PdfPageFormat.a4;
+        break;
+      case RateCardFormat.a5HalfSheet:
+        pageFormat = PdfPageFormat.a5;
+        break;
+      case RateCardFormat.posThermal80mm:
+        pageFormat = const PdfPageFormat(
+          80 * PdfPageFormat.mm,
+          double.infinity,
+          marginAll: 4 * PdfPageFormat.mm,
+        );
+        break;
+      case RateCardFormat.posThermal58mm:
+        pageFormat = const PdfPageFormat(
+          58 * PdfPageFormat.mm,
+          double.infinity,
+          marginAll: 3 * PdfPageFormat.mm,
+        );
+        break;
+    }
+
+    final isThermal = format == RateCardFormat.posThermal80mm ||
+        format == RateCardFormat.posThermal58mm;
+
+    pdf.addPage(
+      pw.Page(
+        pageFormat: pageFormat,
+        build: (pw.Context context) {
+          if (isThermal) {
+            return _buildThermalLayout(
+              storeName: storeName,
+              brackets: brackets,
+              gcashNumber: gcashNumber,
+              is58mm: format == RateCardFormat.posThermal58mm,
+            );
+          }
+          return _buildStandardSheetLayout(
+            storeName: storeName,
+            brackets: brackets,
+            gcashNumber: gcashNumber,
+            isA5: format == RateCardFormat.a5HalfSheet,
+          );
+        },
+      ),
+    );
+
+    return pdf.save();
+  }
+
+  /// Print or share rate card using OS printing dialog
+  static Future<void> printOrShareRateCard({
+    required String storeName,
+    required List<GcashFeeBracket> brackets,
+    RateCardFormat format = RateCardFormat.a4Sheet,
+    String? gcashNumber,
+  }) async {
+    final bytes = await generateRateCardPdf(
+      storeName: storeName,
+      brackets: brackets,
+      format: format,
+      gcashNumber: gcashNumber,
+    );
+
+    await Printing.layoutPdf(
+      onLayout: (PdfPageFormat _) async => bytes,
+      name: 'TindaGrid_${storeName}_GCash_Rate_Card',
+    );
+  }
+
+  /// High-contrast layout for A4/A5 store posters
+  static pw.Widget _buildStandardSheetLayout({
+    required String storeName,
+    required List<GcashFeeBracket> brackets,
+    String? gcashNumber,
+    required bool isA5,
+  }) {
+    final titleSize = isA5 ? 18.0 : 24.0;
+    final subtitleSize = isA5 ? 12.0 : 14.0;
+    final rowFontSize = isA5 ? 11.0 : 13.0;
+
+    return pw.Container(
+      padding: pw.EdgeInsets.all(isA5 ? 12 : 20),
+      decoration: pw.BoxDecoration(
+        border: pw.Border.all(color: PdfColors.blue900, width: 3),
+        borderRadius: pw.BorderRadius.circular(12),
+      ),
+      child: pw.Column(
+        crossAxisAlignment: pw.CrossAxisAlignment.stretch,
+        children: [
+          // Header Banner
+          pw.Container(
+            padding: const pw.EdgeInsets.symmetric(vertical: 12, horizontal: 16),
+            decoration: const pw.BoxDecoration(
+              color: PdfColors.blue800,
+              borderRadius: pw.BorderRadius.all(pw.Radius.circular(8)),
+            ),
+            child: pw.Column(
+              children: [
+                pw.Text(
+                  'GCASH CASH-IN & CASH-OUT',
+                  style: pw.TextStyle(
+                    fontSize: titleSize,
+                    fontWeight: pw.FontWeight.bold,
+                    color: PdfColors.white,
+                  ),
+                  textAlign: pw.TextAlign.center,
+                ),
+                pw.SizedBox(height: 4),
+                pw.Text(
+                  storeName.toUpperCase(),
+                  style: pw.TextStyle(
+                    fontSize: subtitleSize,
+                    fontWeight: pw.FontWeight.bold,
+                    color: PdfColors.amber300,
+                  ),
+                  textAlign: pw.TextAlign.center,
+                ),
+                if (gcashNumber != null && gcashNumber.isNotEmpty) ...[
+                  pw.SizedBox(height: 4),
+                  pw.Text(
+                    'GCash No: $gcashNumber',
+                    style: pw.TextStyle(
+                      fontSize: subtitleSize,
+                      color: PdfColors.white,
+                    ),
+                  ),
+                ],
+              ],
+            ),
+          ),
+          pw.SizedBox(height: 16),
+
+          // Rates Table
+          pw.TableHelper.fromTextArray(
+            headers: ['TRANSACTION AMOUNT (HALAGA)', 'SERVICE FEE (PATONG)'],
+            headerStyle: pw.TextStyle(
+              fontSize: rowFontSize,
+              fontWeight: pw.FontWeight.bold,
+              color: PdfColors.white,
+            ),
+            headerDecoration: const pw.BoxDecoration(color: PdfColors.blue700),
+            cellAlignment: pw.Alignment.centerLeft,
+            cellAlignments: {
+              0: pw.Alignment.centerLeft,
+              1: pw.Alignment.centerRight,
+            },
+            cellStyle: pw.TextStyle(fontSize: rowFontSize),
+            data: brackets.map((b) {
+              final rangeStr = 'P ${b.minAmount.toStringAsFixed(0)} - P ${b.maxAmount.toStringAsFixed(0)}';
+              final feeStr = b.percentageFee > 0
+                  ? '${b.percentageFee.toStringAsFixed(1)}%'
+                  : 'P ${b.fixedFee.toStringAsFixed(2)}';
+              return [rangeStr, feeStr];
+            }).toList(),
+            border: pw.TableBorder.all(color: PdfColors.grey400, width: 0.5),
+            headerPadding: const pw.EdgeInsets.symmetric(vertical: 8, horizontal: 10),
+            cellPadding: const pw.EdgeInsets.symmetric(vertical: 8, horizontal: 10),
+          ),
+          pw.SizedBox(height: 16),
+
+          // Security & Instructions Footer
+          pw.Container(
+            padding: const pw.EdgeInsets.all(10),
+            decoration: pw.BoxDecoration(
+              color: PdfColors.grey100,
+              border: pw.Border.all(color: PdfColors.grey300),
+              borderRadius: pw.BorderRadius.circular(6),
+            ),
+            child: pw.Column(
+              crossAxisAlignment: pw.CrossAxisAlignment.start,
+              children: [
+                pw.Text(
+                  'PAALALA SA MGA SUKI:',
+                  style: pw.TextStyle(
+                    fontWeight: pw.FontWeight.bold,
+                    fontSize: isA5 ? 9.0 : 10.0,
+                    color: PdfColors.red800,
+                  ),
+                ),
+                pw.SizedBox(height: 2),
+                pw.Text(
+                  '* I-double check ang numero bago mag-confirm ng send.',
+                  style: pw.TextStyle(fontSize: isA5 ? 8.5 : 9.5),
+                ),
+                pw.Text(
+                  '* Ipakita ang Reference Number o SMS resibo sa tindera bago kunin ang pera.',
+                  style: pw.TextStyle(fontSize: isA5 ? 8.5 : 9.5),
+                ),
+                pw.Text(
+                  '* Bawal ang reused screenshot. Automatic na nade-detect ang duplicate reference numbers.',
+                  style: pw.TextStyle(fontSize: isA5 ? 8.5 : 9.5),
+                ),
+              ],
+            ),
+          ),
+          pw.Spacer(),
+
+          // Powered by TindaGrid footer
+          pw.Center(
+            child: pw.Text(
+              'Generated with TindaGrid - Offline-First Sari-Sari OS',
+              style: pw.TextStyle(
+                fontSize: 8,
+                color: PdfColors.grey600,
+                fontStyle: pw.FontStyle.italic,
+              ),
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+
+  /// POS Thermal Receipt layout (58mm / 80mm)
+  static pw.Widget _buildThermalLayout({
+    required String storeName,
+    required List<GcashFeeBracket> brackets,
+    String? gcashNumber,
+    required bool is58mm,
+  }) {
+    final baseFont = is58mm ? 8.0 : 10.0;
+    final headerFont = is58mm ? 10.0 : 12.0;
+
+    return pw.Column(
+      crossAxisAlignment: pw.CrossAxisAlignment.stretch,
+      children: [
+        pw.Center(
+          child: pw.Text(
+            storeName.toUpperCase(),
+            style: pw.TextStyle(fontSize: headerFont, fontWeight: pw.FontWeight.bold),
+          ),
+        ),
+        pw.Center(
+          child: pw.Text(
+            'GCASH RATES',
+            style: pw.TextStyle(fontSize: baseFont, fontWeight: pw.FontWeight.bold),
+          ),
+        ),
+        if (gcashNumber != null && gcashNumber.isNotEmpty)
+          pw.Center(
+            child: pw.Text(
+              'No: $gcashNumber',
+              style: pw.TextStyle(fontSize: baseFont),
+            ),
+          ),
+        pw.Divider(thickness: 1, borderStyle: pw.BorderStyle.dashed),
+        ...brackets.map((b) {
+          final rangeStr = '${b.minAmount.toStringAsFixed(0)}-${b.maxAmount.toStringAsFixed(0)}';
+          final feeStr = b.percentageFee > 0
+              ? '${b.percentageFee.toStringAsFixed(1)}%'
+              : 'P${b.fixedFee.toStringAsFixed(0)}';
+
+          return pw.Padding(
+            padding: const pw.EdgeInsets.symmetric(vertical: 2),
+            child: pw.Row(
+              mainAxisAlignment: pw.MainAxisAlignment.spaceBetween,
+              children: [
+                pw.Text(rangeStr, style: pw.TextStyle(fontSize: baseFont)),
+                pw.Text(
+                  feeStr,
+                  style: pw.TextStyle(fontSize: baseFont, fontWeight: pw.FontWeight.bold),
+                ),
+              ],
+            ),
+          );
+        }),
+        pw.Divider(thickness: 1, borderStyle: pw.BorderStyle.dashed),
+        pw.Center(
+          child: pw.Text(
+            'Salamat sa Tiwala!',
+            style: pw.TextStyle(fontSize: baseFont, fontStyle: pw.FontStyle.italic),
+          ),
+        ),
+      ],
+    );
+  }
+}

frontend/pubspec.lock

@@ -17,6 +17,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "13.0.0"
+  archive:
+    dependency: transitive
+    description:
+      name: archive
+      sha256: "0d58d1fa1fddf6588251ccf2819f3fb3b6d0452c1b2813ac7413a05592bfbefe"
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.5.2"
   args:
     dependency: transitive
     description:
@@ -89,6 +97,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "4.4.1"
+  barcode:
+    dependency: transitive
+    description:
+      name: barcode
+      sha256: "7b6729c37e3b7f34233e2318d866e8c48ddb46c1f7ad01ff7bb2a8de1da2b9f4"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.2.9"
+  bidi:
+    dependency: transitive
+    description:
+      name: bidi
+      sha256: "77f475165e94b261745cf1032c751e2032b8ed92ccb2bf5716036db79320637d"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.0.13"
   boolean_selector:
     dependency: transitive
     description:
@@ -440,6 +464,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "8.2.1"
+  google_mlkit_commons:
+    dependency: transitive
+    description:
+      name: google_mlkit_commons
+      sha256: "621e94de22fd0f1e902e593b892746d80ab7542b39c2552aa091d904eb82fc6f"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.13.0"
+  google_mlkit_text_recognition:
+    dependency: "direct main"
+    description:
+      name: google_mlkit_text_recognition
+      sha256: e13685af5093c8be009a3555909b72a80e10cfe8f97752bcbdf99fa0ccbda810
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.17.1"
   graphs:
     dependency: transitive
     description:
@@ -480,6 +520,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "4.1.2"
+  image:
+    dependency: transitive
+    description:
+      name: image
+      sha256: "89ed75b2f8231fe676808c5564f9590d728024ded7ac782a7ed8474f1c95b72a"
+      url: "https://pub.dev"
+    source: hosted
+    version: "4.12.0"
   intl:
     dependency: transitive
     description:
@@ -696,6 +744,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.9.1"
+  path_parsing:
+    dependency: transitive
+    description:
+      name: path_parsing
+      sha256: "883402936929eac138ee0a45da5b0f2c80f89913e6dc3bf77eb65b84b409c6ca"
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.1.0"
   path_provider:
     dependency: "direct main"
     description:
@@ -744,6 +800,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.3.0"
+  pdf:
+    dependency: "direct main"
+    description:
+      name: pdf
+      sha256: "6e40827f370d196e97c6611724d923a3d86c431ce8e2ce1e59edd03a67a1a6e6"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.13.1"
+  pdf_widget_wrapper:
+    dependency: transitive
+    description:
+      name: pdf_widget_wrapper
+      sha256: c930860d987213a3d58c7ec3b7ecf8085c3897f773e8dc23da9cae60a5d6d0f5
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.0.4"
   petitparser:
     dependency: transitive
     description:
@@ -776,6 +848,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.5.3"
+  posix:
+    dependency: transitive
+    description:
+      name: posix
+      sha256: bc1bad54ad2b735816e31f8d4600cfde6c7839975085ddfbca48b6c9f7c4044e
+      url: "https://pub.dev"
+    source: hosted
+    version: "6.5.2"
+  printing:
+    dependency: "direct main"
+    description:
+      name: printing
+      sha256: "0f72f29f2e08b8453b7a45b6c7781eb792b1da3468bf0910be0eb3b1d6781f49"
+      url: "https://pub.dev"
+    source: hosted
+    version: "5.15.1"
   pub_semver:
     dependency: transitive
     description:

frontend/pubspec.yaml

@@ -51,6 +51,9 @@ dependencies:
   vibration: ^3.2.1
   audioplayers: ^6.8.1
   qr_flutter: ^4.1.0
+  pdf: ^3.13.1
+  printing: ^5.15.1
+  google_mlkit_text_recognition: ^0.17.1
 
 dev_dependencies:
   flutter_test:

frontend/test/gcash_phase4_test.dart

@@ -0,0 +1,175 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:drift/native.dart';
+import 'package:drift/drift.dart' as drift;
+import 'package:tindagrid/core/database/app_database.dart';
+import 'package:tindagrid/features/gcash/gcash_receipt_ocr_service.dart';
+import 'package:tindagrid/features/gcash/rate_card_pdf_service.dart';
+
+void main() {
+  late AppDatabase db;
+
+  setUp(() async {
+    db = AppDatabase.forTesting(NativeDatabase.memory());
+  });
+
+  tearDown(() async {
+    await db.close();
+  });
+
+  group('Phase 4: GCash Float Ledger, Fee Scheduler & Rate Card PDF Tests', () {
+    test('4.1 Dual-Float Tracking Engine calculates real-time balances and fee profit', () async {
+      const baseCash = 5000.0;
+      const baseGcash = 10000.0;
+
+      // 1. Initial State
+      var stream = db.watchDualFloatBalance(baseCash: baseCash, baseGcash: baseGcash);
+      var initial = await stream.first;
+      expect(initial.gcashFloat, equals(10000.0));
+      expect(initial.cashDrawer, equals(5000.0));
+      expect(initial.totalFeesEarned, equals(0.0));
+
+      // 2. Perform Cash-In: Customer deposits ₱500, pays ₱10 fee
+      // Cash Drawer gets ₱510. GCash float loses ₱500.
+      await db.recordGcash(
+        transactionType: 'CASH_IN',
+        amount: 500.0,
+        feeCharged: 10.0,
+        referenceNumber: '1002481029412',
+        customerName: 'Maria Santos',
+        customerPhone: '09171234567',
+      );
+
+      var afterCashIn = await stream.first;
+      expect(afterCashIn.gcashFloat, equals(9500.0));
+      expect(afterCashIn.cashDrawer, equals(5510.0));
+      expect(afterCashIn.totalFeesEarned, equals(10.0));
+      expect(afterCashIn.cashInCount, equals(1));
+
+      // 3. Perform Cash-Out: Customer withdraws ₱1,000, pays ₱15 fee
+      // GCash float receives ₱1,000. Cash Drawer pays out net ₱985 (₱1000 - ₱15 fee)
+      await db.recordGcash(
+        transactionType: 'CASH_OUT',
+        amount: 1000.0,
+        feeCharged: 15.0,
+        referenceNumber: '0021984210984',
+        customerName: 'Juan Dela Cruz',
+        customerPhone: '09189876543',
+      );
+
+      var afterCashOut = await stream.first;
+      expect(afterCashOut.gcashFloat, equals(10500.0));
+      expect(afterCashOut.cashDrawer, equals(4525.0));
+      expect(afterCashOut.totalFeesEarned, equals(25.0));
+      expect(afterCashOut.cashOutCount, equals(1));
+
+      // 4. Store Payment: Customer pays ₱200 grocery bill via GCash QR
+      // GCash float increases by ₱200. Cash drawer untouched.
+      await db.recordGcash(
+        transactionType: 'STORE_PAYMENT',
+        amount: 200.0,
+        feeCharged: 0.0,
+        referenceNumber: '9921048123901',
+      );
+
+      var afterPayment = await stream.first;
+      expect(afterPayment.gcashFloat, equals(10700.0));
+      expect(afterPayment.cashDrawer, equals(4525.0));
+      expect(afterPayment.storePaymentCount, equals(1));
+    });
+
+    test('4.1 Anti-Fraud: Reference number duplicate detection catches recycled receipts', () async {
+      await db.recordGcash(
+        transactionType: 'CASH_IN',
+        amount: 300.0,
+        feeCharged: 10.0,
+        referenceNumber: '1002 9481 02941',
+      );
+
+      // Check with exact string
+      expect(await db.isReferenceNumberUsed('1002 9481 02941'), isTrue);
+
+      // Check without spaces (sanitized comparison)
+      expect(await db.isReferenceNumberUsed('1002948102941'), isTrue);
+
+      // Check non-existing reference number
+      expect(await db.isReferenceNumberUsed('9999999999999'), isFalse);
+    });
+
+    test('4.2 Customizable Fee Brackets seeds, saves, and calculates tiered rates', () async {
+      // 1. Seed defaults
+      await db.seedDefaultFeeBrackets();
+      final brackets = await db.getFeeBrackets();
+      expect(brackets.length, greaterThanOrEqualTo(6));
+
+      // Verify default fee for ₱500 is ₱10.00
+      final fee500 = await db.calculateGcashFee(500.0);
+      expect(fee500, equals(10.0));
+
+      // Verify default fee for ₱800 is ₱15.00
+      final fee800 = await db.calculateGcashFee(800.0);
+      expect(fee800, equals(15.0));
+
+      // 2. Add custom bracket: ₱10,001 - ₱20,000 at 2.0%
+      await db.saveFeeBracket(
+        const GcashFeeConfigCompanion(
+          id: drift.Value('bracket-tier-high'),
+          minAmount: drift.Value(10001.0),
+          maxAmount: drift.Value(20000.0),
+          fixedFee: drift.Value(0.0),
+          percentageFee: drift.Value(2.0),
+        ),
+      );
+
+      final fee15000 = await db.calculateGcashFee(15000.0);
+      expect(fee15000, equals(300.0)); // 2% of 15,000
+    });
+
+    test('4.3 Printable Rate Card PDF generates valid bytes for A4, A5, and Thermal formats', () async {
+      await db.seedDefaultFeeBrackets();
+      final brackets = await db.getFeeBrackets();
+
+      // Test A4 Sheet PDF
+      final a4Bytes = await RateCardPdfService.generateRateCardPdf(
+        storeName: 'Aling Nena Tindahan',
+        brackets: brackets,
+        format: RateCardFormat.a4Sheet,
+        gcashNumber: '0917-123-4567',
+      );
+      expect(a4Bytes, isNotEmpty);
+      expect(a4Bytes.length, greaterThan(1000));
+
+      // Test A5 Half Sheet PDF
+      final a5Bytes = await RateCardPdfService.generateRateCardPdf(
+        storeName: 'Aling Nena Tindahan',
+        brackets: brackets,
+        format: RateCardFormat.a5HalfSheet,
+      );
+      expect(a5Bytes, isNotEmpty);
+
+      // Test 80mm POS Thermal Receipt PDF
+      final thermalBytes = await RateCardPdfService.generateRateCardPdf(
+        storeName: 'Aling Nena Tindahan',
+        brackets: brackets,
+        format: RateCardFormat.posThermal80mm,
+      );
+      expect(thermalBytes, isNotEmpty);
+    });
+
+    test('4.4 On-Device Receipt OCR parses 13-digit Reference and Amount from raw text', () {
+      const smsText =
+          'You have received PHP 1,500.00 of GCash from Juan Dela Cruz (09181234567) on 10/20/2026. Ref. No. 1002 481 029412.';
+
+      final result = GcashReceiptOcrService.parseRawText(smsText);
+      expect(result.isSuccess, isTrue);
+      expect(result.referenceNumber, equals('1002481029412'));
+      expect(result.amount, equals(1500.0));
+
+      // Test solid reference format
+      const solidRefText = 'Transaction Successful! Amount: P 250.00 Ref No: 0021482910245';
+      final solidResult = GcashReceiptOcrService.parseRawText(solidRefText);
+      expect(solidResult.isSuccess, isTrue);
+      expect(solidResult.referenceNumber, equals('0021482910245'));
+      expect(solidResult.amount, equals(250.0));
+    });
+  });
+}