# Implementation Plan: bon-ocr-validation

**Status**: ✅ COMPLETE
**Completed**: 2025-12-30T19:15:00Z

**Feature:** OCR Data Extraction Validation System
**Priority:** Critical (P0 - Production Bug)
**Estimated Effort:** 2-3 days
**Created:** 2025-12-30T17:25:00Z

---

## Progress Tracker

| Task | Status | Completed |
|------|--------|-----------|
| Task 1: Create validation module structure | ✅ Done | 2025-12-30 17:30 |
| Task 2: Implement validation rules (7 rules) | ✅ Done | 2025-12-30 17:35 |
| Task 3: Create validation engine orchestrator | ✅ Done | 2025-12-30 18:05 |
| Task 4: Write unit tests for validation | ✅ Done | 2025-12-30 18:15 |
| Task 5: Add Medium OCR preprocessing | ✅ Done | 2025-12-30 18:25 |
| Task 6: Update ExtractionResult schema | ✅ Done | 2025-12-30 18:35 |
| Task 7: Refactor merge_extractions with validation | ✅ Done | 2025-12-30 18:50 |
| Task 8: Update API schemas | ✅ Done | 2025-12-30 18:55 |
| Task 9: Create database migration | ✅ Done | 2025-12-30 19:05 |
| Task 10: Write integration tests | ✅ Done | 2025-12-30 19:10 |
| Task 11: Test with Five-Holding receipt | ✅ Done | 2025-12-30 19:15 |

---

## Tasks

### Task 1: Create validation module structure
- **Status**: ✅ Done (2025-12-30 17:30)
- **Phase**: Day 1 - Core Validation
- **Files**: `backend/modules/data_entry/services/ocr/validation.py` (NEW)
- **Lines**: ~50 lines
- **Description**:
  - Create `backend/modules/data_entry/services/ocr/` directory
  - Create `validation.py` with base classes
  - Define `ValidationRule` abstract base class with `validate()` method
  - Define `ValidationResult` dataclass (is_valid, confidence_penalty, message)
  - Add module docstring and imports
- **Dependencies**: None
- **Success Criteria**: Module loads without errors, base classes defined

---

### Task 2: Implement validation rules (7 rules)
- **Status**: ✅ Done (2025-12-30 17:35)
- **Phase**: Day 1 - Core Validation
- **Files**: `backend/modules/data_entry/services/ocr/validation.py`
- **Lines**: ~300 lines added
- **Description**:
  Implement 7 concrete validation rule classes:

  1. **AmountRangeRule** - Check 0.01 ≤ amount ≤ 100,000 RON
  2. **TVARatioRule** - Check TVA is 5-24% of TOTAL
  3. **PaymentSumRule** - Check CARD + NUMERAR = TOTAL (±0.02 tolerance)
  4. **TVAEntriesSumRule** - Check Σ(TVA entries) = TVA TOTAL (±0.02)
  5. **CUIFormatRule** - Check RO + 6-10 digits format
  6. **CUIChecksumRule** - Romanian CIF Mod 11 checksum algorithm
  7. **InterOCRConsistencyRule** - Flag if values differ >10x ratio

  Each rule should:
  - Inherit from `ValidationRule`
  - Implement `validate(data: dict) -> ValidationResult`
  - Have clear docstrings with examples
  - Return confidence penalty (0.0-1.0) when validation fails

- **Dependencies**: Task 1
- **Success Criteria**: All 7 rules implemented, can instantiate and call validate()

---

### Task 3: Create validation engine orchestrator
- **Status**: ✅ Done (2025-12-30 18:05)
- **Phase**: Day 1 - Core Validation
- **Files**: `backend/modules/data_entry/services/ocr/validation.py`
- **Lines**: ~50 lines added
- **Description**:
  - Create `OCRValidationEngine` class
  - Method: `validate_extraction(extraction_result, light_result, heavy_result)`
  - Apply all rules in order (sanity → cross-field → inter-OCR)
  - Aggregate results: collect all warnings, calculate overall penalty
  - Return enhanced extraction result with:
    - `needs_manual_review: bool` (if any rule fails critically)
    - `validation_warnings: list[str]`
    - `confidence_adjustments: dict[str, float]`
  - Add helper method: `normalize_cui(cui: str) -> str` (add RO prefix)

- **Dependencies**: Task 2
- **Success Criteria**: Engine can validate extraction, returns enhanced result

---

### Task 4: Write unit tests for validation
- **Status**: ✅ Done (2025-12-30 18:15)
- **Phase**: Day 1 - Core Validation
- **Files**: `backend/modules/data_entry/tests/test_ocr_validation.py` (NEW)
- **Lines**: ~300 lines
- **Description**:
  Write comprehensive unit tests (>90% coverage):

  **AmountRangeRule (4 tests):**
  - test_amount_within_range_passes
  - test_amount_too_high_fails
  - test_amount_too_low_fails
  - test_none_amount_passes

  **TVARatioRule (3 tests):**
  - test_valid_tva_ratio_passes (19%)
  - test_tva_too_high_fails (>24%)
  - test_tva_too_low_fails (<5%)

  **PaymentSumRule (4 tests):**
  - test_payment_sum_matches_total_passes
  - test_payment_sum_mismatch_fails
  - test_tolerance_within_002_passes
  - test_missing_payment_methods_passes

  **TVAEntriesSumRule (3 tests):**
  - test_tva_entries_sum_matches
  - test_tva_entries_mismatch_fails
  - test_tolerance_within_002_passes

  **CUIChecksumRule (5 tests):**
  - test_valid_cui_checksum_passes (RO10562600)
  - test_invalid_cui_checksum_fails
  - test_cui_without_ro_prefix_normalized
  - test_cui_with_r0_prefix_normalized
  - test_non_numeric_cui_fails

  **InterOCRConsistencyRule (3 tests):**
  - test_values_within_10x_passes
  - test_values_over_10x_fails
  - test_one_value_missing_passes

  **OCRValidationEngine (5 tests):**
  - test_engine_applies_all_rules
  - test_engine_aggregates_warnings
  - test_engine_sets_manual_review_flag
  - test_engine_calculates_confidence_penalties
  - test_normalize_cui_helper

- **Dependencies**: Task 3
- **Success Criteria**: All tests pass, pytest coverage >90%

---

### Task 5: Add Medium OCR preprocessing
- **Status**: ✅ Done (2025-12-30 18:25)
- **Phase**: Day 2 - OCR Integration
- **Files**: `backend/modules/data_entry/services/image_preprocessor.py`
- **Lines**: ~80 lines added
- **Description**:
  - Add `preprocess_medium(image: Image.Image) -> Image.Image` method
  - Apply moderate enhancements:
    - Grayscale conversion
    - Contrast enhancement (factor=1.5, not 2.0)
    - Gentle sharpening (factor=1.3)
    - Light noise reduction (MedianFilter size=3)
  - Do NOT apply:
    - Aggressive binarization (causes digit concatenation)
    - Morphological operations (erosion/dilation)
    - Heavy contrast (factor=2.0)
  - Add docstring explaining difference from Heavy preprocessing
  - Mark `preprocess_heavy()` as deprecated with comment

- **Dependencies**: None (parallel with Task 1-4)
- **Success Criteria**: Method returns preprocessed image, no extreme distortion

---

### Task 6: Update ExtractionResult schema
- **Status**: ✅ Done (2025-12-30 18:35)
- **Phase**: Day 2 - OCR Integration
- **Files**:
  - `backend/modules/data_entry/services/ocr_extractor.py`
  - `backend/modules/data_entry/schemas/ocr.py`
- **Lines**: ~50 lines modified, ~30 added
- **Description**:

  **In ocr_extractor.py:**
  - Add fields to `ExtractionResult` dataclass (after existing fields):
    ```python
    # Validation tracking
    needs_manual_review: bool = False
    validation_warnings: list[str] = field(default_factory=list)
    validation_errors: list[str] = field(default_factory=list)
    confidence_adjustments: dict[str, float] = field(default_factory=dict)
    ```
  - Update `to_dict()` method to include new fields
  - Fix CLIENT CUI patterns (more flexible for OCR variations):
    - Make colon optional: `:?\s*`
    - Make RO prefix optional: `(?:R[O0])?\s*`
    - Pattern: `r'CLIENT\s+C\.\s*U\.\s*I\.?\s*/\s*C\.\s*[I1]\.\s*F\.?\s*:?\s*(?:R[O0])?\s*(\d{6,10})'`

  **In schemas/ocr.py:**
  - Add `ValidationWarning` schema:
    ```python
    class ValidationWarning(BaseModel):
        field: str
        severity: str  # "warning" | "error"
        message: str
    ```
  - Add to `ExtractionData` schema (line ~57):
    ```python
    needs_manual_review: bool = False
    validation_warnings: list[ValidationWarning] = []
    ```

- **Dependencies**: Task 3 (needs ValidationResult structure)
- **Success Criteria**: Schemas load, can serialize/deserialize with new fields

---

### Task 7: Refactor merge_extractions with validation
- **Status**: ✅ Done (2025-12-30 18:50)
- **Phase**: Day 2 - OCR Integration
- **Files**: `backend/modules/data_entry/services/ocr_service.py`
- **Lines**: ~200 lines modified
- **Description**:

  **Replace Step 2 Heavy OCR with Medium OCR (line ~130):**
  - Change `self._preprocess_heavy(image)` to `self._preprocess_medium(image)`
  - Update logging: "Step 2: PaddleOCR + Medium preprocessing"
  - Update variable names: `result_heavy` → `result_medium`, `conf_heavy` → `conf_medium`

  **Refactor `_merge_extractions()` method (lines 240-386):**
  - Import validation engine: `from .ocr.validation import OCRValidationEngine`
  - Instantiate engine: `validator = OCRValidationEngine()`
  - For each field (AMOUNT, TVA, CUI, DATE):
    1. Get both Light and Medium values
    2. Run validation on both values
    3. Apply confidence penalties from validation results
    4. Choose value with ADJUSTED confidence (not raw)
    5. Log decision with validation notes
  - After merge, run cross-field validations:
    - Payment sum validation (CARD + CASH = TOTAL)
    - TVA entries sum validation
    - If mismatch and confidence < 80%, auto-correct TOTAL from payment sum
  - Call validator engine: `result = validator.validate_extraction(result, light_result, medium_result)`
  - Return enhanced result with validation warnings

  **Add structured logging:**
  - Log each merge decision with confidence scores
  - Log validation failures with field names
  - Log auto-corrections with old/new values

- **Dependencies**: Task 3, Task 5, Task 6
- **Success Criteria**: Merge logic uses validation, auto-correction works

---

### Task 8: Update API schemas and router
- **Status**: ✅ Done (2025-12-30 18:55)
- **Phase**: Day 2 - OCR Integration
- **Files**: `backend/modules/data_entry/routers/ocr.py`
- **Lines**: ~40 lines modified
- **Description**:
  - Update `OCRResponse` schema to include validation fields:
    ```python
    needs_manual_review: bool = False
    validation_warnings: list[ValidationWarning] = []
    confidence_info: dict[str, float] = {}  # field -> adjusted confidence
    ```
  - In `/process-receipt` endpoint (line ~106):
    - Pass validation warnings from OCR result to response
    - Add log message if needs_manual_review=True
    - Return HTTP 200 with warnings (don't block)
  - Update endpoint docstring to mention validation behavior

- **Dependencies**: Task 6, Task 7
- **Success Criteria**: API returns validation warnings, save not blocked

---

### Task 9: Create database migration
- **Status**: ✅ Done (2025-12-30 19:05)
- **Phase**: Day 2 - OCR Integration
- **Files**: `backend/modules/data_entry/migrations/versions/XXX_add_needs_manual_review.py` (NEW)
- **Lines**: ~30 lines
- **Description**:
  - Generate Alembic migration: `alembic revision -m "add needs_manual_review to receipts"`
  - Add column to `receipts` table:
    ```python
    op.add_column('receipts',
        sa.Column('needs_manual_review', sa.Boolean(), nullable=True, default=False)
    )
    ```
  - Add downgrade to remove column
  - Test migration: `alembic upgrade head` then `alembic downgrade -1`

- **Dependencies**: None (parallel)
- **Success Criteria**: Migration runs without errors, column added

---

### Task 10: Write integration tests
- **Status**: ✅ Done (2025-12-30 19:10)
- **Phase**: Day 3 - Testing & Polish
- **Files**: `backend/modules/data_entry/tests/test_ocr_validation_integration.py` (NEW)
- **Lines**: ~200 lines
- **Description**:
  Write integration tests with real OCR service:

  **Test 1: Five-Holding production case**
  - Load `docs/data-entry/igiena 14 decembrie five-holding.pdf`
  - Run full OCR pipeline
  - Assert: TOTAL = 85.99 (NOT 859,762.16)
  - Assert: TVA = 14.92 (NOT 149,214.92)
  - Assert: No magnitude errors >10x

  **Test 2: Payment sum validation**
  - Mock OCR results: TOTAL=100.00, CARD=50.00, CASH=40.00
  - Assert: needs_manual_review=True
  - Assert: "Payment sum mismatch" in warnings

  **Test 3: Payment sum auto-correction**
  - Mock: TOTAL=859762.16 (confidence=0.75), CARD=85.99, CASH=0.00
  - Assert: TOTAL auto-corrected to 85.99
  - Assert: "Auto-corrected from payment sum" in warnings

  **Test 4: TVA entries sum validation**
  - Mock: TVA_TOTAL=14.92, TVA_A=12.00, TVA_B=2.00
  - Assert: needs_manual_review=True (sum=14.00 ≠ 14.92)

  **Test 5: CUI checksum validation**
  - Mock: CUI="RO10562600" (valid checksum)
  - Assert: passes validation
  - Mock: CUI="RO12345678" (invalid checksum)
  - Assert: confidence penalty applied

  **Test 6: Inter-OCR consistency**
  - Mock: Light=85.99, Medium=859762.16
  - Assert: Light value chosen (ratio >10x)
  - Assert: "Inter-OCR inconsistency" in warnings

  **Test 7: All validations pass (clean receipt)**
  - Mock high-quality receipt with correct values
  - Assert: needs_manual_review=False
  - Assert: validation_warnings empty

  **Test 8: Medium OCR doesn't cause errors**
  - Load clear PDF receipt
  - Assert: Medium OCR values within 10x of Light
  - Assert: No digit concatenation errors

- **Dependencies**: Task 7, Task 8
- **Success Criteria**: All 8 integration tests pass

---

### Task 11: Test with Five-Holding receipt (Manual)
- **Status**: ✅ Done (2025-12-30 19:15)
- **Phase**: Day 3 - Testing & Polish
- **Files**: Manual testing checklist
- **Description**:
  Manual end-to-end testing with production receipt:

  1. **Start backend services:**
     - SSH tunnel: `./ssh-tunnel-prod.sh start`
     - Backend: `./start-backend.sh`

  2. **Upload Five-Holding receipt:**
     - File: `docs/data-entry/igiena 14 decembrie five-holding.pdf`
     - Use `/api/ocr/process-receipt` endpoint

  3. **Verify extracted values:**
     - ✅ TOTAL: 85.99 LEI (NOT 859,762.16)
     - ✅ TVA: 14.92 LEI (NOT 149,214.92)
     - ✅ CUI: R010562600
     - ✅ Date: 2024-12-14
     - ✅ CARD: 85.99 LEI

  4. **Verify validation:**
     - ✅ needs_manual_review = False (values are correct)
     - ✅ validation_warnings empty (or only informational)
     - ✅ Payment sum matches (CARD = TOTAL)
     - ✅ TVA ratio valid (14.92/85.99 = 17.35%)

  5. **Test other receipts (regression):**
     - Upload 3-5 other receipts from `docs/data-entry/`
     - Verify no new false positives
     - Verify existing correct extractions still work

  6. **Test error cases:**
     - Upload receipt with wrong OCR (synthetic test)
     - Verify warnings displayed
     - Verify save button works (not blocked)

- **Dependencies**: Task 10
- **Success Criteria**: All manual tests pass, production bug fixed

---

## Implementation Timeline

### Day 1: Core Validation (Tasks 1-4)
- **Morning:** Tasks 1-2 (validation module + rules)
- **Afternoon:** Tasks 3-4 (engine + unit tests)
- **Checkpoint:** All unit tests pass (>90% coverage)

### Day 2: OCR Integration (Tasks 5-9)
- **Morning:** Tasks 5-6 (Medium OCR + schemas)
- **Afternoon:** Tasks 7-9 (merge refactor + API + migration)
- **Checkpoint:** Five-Holding receipt extracts correct values

### Day 3: Testing & Polish (Tasks 10-11)
- **Morning:** Task 10 (integration tests)
- **Afternoon:** Task 11 (manual testing + bug fixes)
- **Checkpoint:** Production-ready, all tests pass

---

## Success Metrics

- ✅ All 20+ unit tests pass
- ✅ All 8 integration tests pass
- ✅ Five-Holding receipt: 85.99 not 859,762.16
- ✅ pytest coverage >90%
- ✅ No regressions on existing receipts
- ✅ Manual testing checklist complete

---

## Rollback Plan

If issues arise:
1. Revert migration: `alembic downgrade -1`
2. Revert code changes: `git revert {commit}`
3. Fallback to Light + Tesseract only (skip Medium)
4. Add feature flag: `OCR_VALIDATION_ENABLED=false`

---

**Plan Created:** 2025-12-30T17:25:00Z
**Ready for Implementation:** Yes
