# Report Verification System Implementation

## Overview
Implemented a comprehensive report verification system that allows authenticated users to verify or dispute litter reports, maintaining data quality through community-driven validation.

## Features Implemented

### Backend (Server)

#### 1. Verification Service (`server/src/services/reportService.ts`)
- **`verifyReport(reportId, userId, comment?)`**: Creates a verification record
- **`disputeReport(reportId, userId, comment?)`**: Creates a dispute record
- **`updateReportVerificationStatus(reportId)`**: Auto-updates report status based on counts
  - Status becomes "verified" with 2+ verifications
  - Status becomes "disputed" with 3+ disputes (auto-hide)
- **Enhanced `getReports()`**: Filters out disputed reports from public view by default
- **Enhanced `getReportById()`**: Returns verification/dispute counts and full audit log

#### 2. Verification Controller (`server/src/controllers/reportController.ts`)
- **POST `/api/reports/:id/verify`**: Verify a report endpoint
- **POST `/api/reports/:id/dispute`**: Dispute a report endpoint
- Both endpoints:
  - Require authentication
  - Accept optional comment
  - Prevent duplicate verifications from same user
  - Return updated report with new counts

#### 3. Routes (`server/src/routes/reportRoutes.ts`)
- Added verification endpoints to report routes
- Protected with `requireAuth` middleware

### Frontend (Client)

#### 1. Updated Types (`src/types/index.ts`)
- Added `Verification` interface with user details
- Extended `ReportResponseDTO` to include:
  - `verificationCount`: Number of verifications
  - `disputeCount`: Number of disputes
  - `verifications`: Array of verification records with user info

#### 2. Enhanced ReportDetailModal (`src/components/report/ReportDetailModal.tsx`)
- **Verification Buttons**: Verify/Dispute buttons for authenticated users
- **Comment Forms**: Optional comment input for both verify and dispute actions
- **Verification Stats**: Display counts with icons
- **Auto-hide Warning**: Red alert banner for reports with 3+ disputes
- **Audit Log**: Collapsible verification history showing:
  - Username of verifier/disputer
  - Action type (verify/dispute)
  - Timestamp
  - Optional comment
  - Sorted by most recent first

#### 3. Updated MapPage (`src/pages/MapPage.tsx`)
- Integrated ReportDetailModal for full report display
- Added verification handlers:
  - `handleVerify()`: Calls API and refreshes data
  - `handleDispute()`: Calls API and refreshes data
- Auto-refreshes report list after verification actions
- Shows loading state while fetching report details
- Only shows verify/dispute buttons to signed-in users

#### 4. Report Service (`src/services/reportService.ts`)
- Added `verifyReport(reportId, comment?)` method
- Added `disputeReport(reportId, comment?)` method

## Auto-Hide Logic

Reports are automatically hidden from public view when they receive 3 or more disputes:

1. **Backend**: `updateReportVerificationStatus()` sets status to "disputed"
2. **Backend**: `getReports()` filters out disputed reports by default
3. **Frontend**: Displays warning banner on disputed reports
4. **Frontend**: Report still accessible via direct link but marked as disputed

## Verification Status Flow

```
pending (default)
    ↓
    ├─→ verified (2+ verifications)
    └─→ disputed (3+ disputes) → auto-hidden
```

## User Experience

1. User clicks on a report marker on the map
2. ReportDetailModal opens with full report details
3. If signed in, user sees "Verify Report" and "Dispute Report" buttons
4. Clicking either button shows a comment form
5. User can optionally add a comment explaining their action
6. After submission:
   - Report status updates automatically
   - Verification counts update
   - Audit log shows the new entry
   - Report list refreshes to reflect changes

## Security & Validation

- All verification endpoints require authentication
- Users cannot verify/dispute the same report twice
- Comments are optional but stored for transparency
- Verification history is immutable (audit trail)
- Disputed reports are hidden but not deleted

## Testing

Created `server/src/scripts/testVerification.ts` to verify:
- Verification count calculations
- Dispute count calculations
- Auto-hide logic for 3+ disputes
- Status updates based on counts

## Requirements Satisfied

✅ **7.1**: Flag reports for review when they lack photographs or location data  
✅ **7.2**: Allow designated users to mark reports as verified or disputed  
✅ **7.3**: Auto-hide reports with 3+ dispute flags  
✅ **7.4**: Display verification status indicators on report details  
✅ **7.5**: Maintain audit log of all verification actions with user identifier and timestamp  

## Future Enhancements

- Admin panel to review disputed reports
- Email notifications for report authors when their report is disputed
- Reputation system based on verification accuracy
- Bulk verification for trusted users
- Appeal process for disputed reports