# Excel Pajak Application

## Project Overview

Excel Pajak is a .NET 10.0 console application that connects to a PostgreSQL database to handle tax-related data processing. The application is designed to execute database queries and process employee information, with a focus on connecting to specific database schemas containing employee data.

### Architecture
- **Main Application**: Console application in the `excel_pajak` directory
- **Test Project**: Unit and integration tests in the `excel_pajak_test` directory
- **Technology Stack**: 
  - .NET 10.0
  - PostgreSQL database connectivity via Npgsql
  - Microsoft.Extensions.Configuration for configuration management
  - MSTest for unit testing
  - Moq for mocking dependencies
  - Shouldly for assertions

### Key Components

1. **DatabaseService** (`Services/DatabaseService.cs`): Handles PostgreSQL connections and executes scalar queries
2. **EmployeeInfo Model** (`Models/EmployeeInfo.cs`): Represents employee data structure with employee number and schema
3. **Configuration**: Managed through `appsettings.json` with connection strings and application settings
4. **Examples**: Demonstrates JSON deserialization of employee data

## Building and Running

### Prerequisites
- .NET 10.0 SDK
- PostgreSQL database server (version compatible with Npgsql 10.0.1)
- Access to the configured database (default connection points to localhost:55432)

### Build Commands
```bash
# Restore dependencies
dotnet restore

# Build the application
dotnet build

# Run the application
dotnet run --project excel_pajak/excel_pajak.csproj

# Run tests
dotnet test
```

### Configuration
The application uses `appsettings.json` for configuration:
- Connection string for PostgreSQL database
- Schema list (currently contains "_onx4pzkwkeortehfjthgyfkb7c")
- Year setting (currently "2025")

## Development Conventions

### Coding Standards
- Uses nullable reference types (`#nullable enable`)
- Follows .NET naming conventions
- Implements asynchronous programming patterns where appropriate
- Includes proper error handling with specific exception types

### Testing Approach
- Unit tests for business logic with mocked dependencies
- Integration tests that connect to actual PostgreSQL database
- Tests cover both positive and negative scenarios
- Uses Shouldly for readable assertions

### Error Handling
- Validates input parameters and throws appropriate exceptions
- Handles database connection errors gracefully
- Provides detailed error messages for debugging

## Project Structure
```
excel_pajak/
├── excel_pajak/                 # Main application
│   ├── Models/                  # Data models
│   │   └── EmployeeInfo.cs      # Employee data structure
│   ├── Services/                # Business logic services
│   │   └── DatabaseService.cs   # PostgreSQL database operations
│   ├── Examples/                # Usage examples
│   │   └── EmployeeJsonExample.cs # JSON processing example
│   ├── Program.cs              # Application entry point
│   ├── appsettings.json        # Configuration file
│   └── excel_pajak.csproj      # Project file
├── excel_pajak_test/           # Test project
│   ├── DatabaseServiceTests.cs # Unit tests
│   ├── DatabaseServiceIntegrationTests.cs # Integration tests
│   └── excel_pajak_test.csproj # Test project file
└── openspec/                   # OpenAPI specification directory
```

## Database Connection
The application connects to PostgreSQL using Npgsql with the connection string defined in `appsettings.json`. The default configuration connects to:
- Server: localhost
- Port: 55432
- Database: andal_kharisma
- User: postgres
- Password: Release@2024

## Testing
The project includes both unit tests (with mocked dependencies) and integration tests (requiring a live database connection). Unit tests validate the logic without external dependencies, while integration tests verify actual database connectivity and query execution.

To run integration tests, ensure that a PostgreSQL database is accessible with the configured connection string.