top_drives/docs/ARCHITECTURE.md

# Architecture Documentation

## System Overview

The Top Drives Records Analyzer consists of a main analysis binary and a shared library working together to provide comprehensive car performance analysis for the Top Drives racing game.

## Component Architecture

### 1. Records Module (`src/records.rs`)

**Primary analysis engine** that processes pre-downloaded JSON timing data.

#### Key Responsibilities
- **Data Fetching**: Downloads car and track databases from GitHub repository
- **File Processing**: Parses JSON timing files for each car configuration
- **Performance Analysis**: Compares timing data across RQ ranges and track conditions
- **Collection Management**: Identifies owned cars and optimization opportunities

#### Key Constants
- `MAX_RQ: u8 = 113` — Maximum RQ level used for range analysis (replaces former magic number 115)

#### Data Flow

```
GitHub Repository
       ↓
cars_repo.json + tracks_repo.json
       ↓
times/*.json (1000+ car files)
       ↓
JSON Parsing → BestCarRecord Analysis
       ↓
User Collection (my_cars.json)
       ↓
Output: CSV/Terminal Results
```

### 2. Shared Library (`src/lib.rs`)

**Common utilities** shared across the project.

#### Key Responsibilities
- **Track Name Translation**: Converts track codes to human-readable names via `translate_track_name()`
- **Track Type Translation**: Converts condition codes to surface descriptions via `translate_track_type()`

#### Configuration
- Track name mappings are loaded from `track_names.json` at compile time using `include_str!`
- This external config file maps track codes (e.g., `"laguna"`) to human-readable names (e.g., `"Laguna Seca"`)

## Data Structures

### Core Types

#### TripletKey
```rust
type TripletKey = (String, u8, String);
//   ↓           ↓        ↓
// Track ID    RQ Level  Surface Condition
```

**Purpose**: Composite key for uniquely identifying track conditions
**Usage**: HashMap key for storing best car records

#### Car
```rust
struct Car {
    rid: String,        // Repository ID
    brand: String,      // Manufacturer
    only_name: String,  // Model name
    year: u16,         // Model year
    rq: u8,           // Rarity level
    prize: bool,       // Prize car status
    guid: String,      // Game GUID
}
```

#### BestCarRecord
```rust
struct BestCarRecord {
    car_rid: String,   // Car identifier
    brand: String,     // Manufacturer
    only_name: String, // Model name
    year: u16,        // Year
    rq: u8,           // RQ level
    config: String,    // Tune config (111, 233, etc.)
    time: f64,        // Track time (seconds)
    owned: bool,      // User ownership status
    guid: String,     // Game identifier
}
```

## Global State Management

### BEST_CARS Cache
```rust
static BEST_CARS: Lazy<Mutex<HashMap<TripletKey, Vec<BestCarRecord>>>>
```

**Thread Safety**: Protected by `Mutex` for concurrent access during parsing
**Initialization**: Uses `once_cell::Lazy` for one-time setup
**Structure**: HashMap with composite keys for efficient lookups

## Algorithm Details

### RQ Range Analysis

The system analyzes car performance across multiple RQ brackets:

1. **Base RQ**: Car's natural rarity level
2. **RQ Range**: Tests from car's RQ up to `MAX_RQ` (113)
3. **Cross-RQ Competition**: Allows cars to compete above their base level

**Example**: A RQ 85 car might perform well at RQ 90-95 levels against higher-rated cars

### Time Validation

Multiple validation layers ensure data quality:

1. **Minimum Time**: Times below 1.2 seconds are discarded
2. **Downvote Filter**: Community-downvoted times are excluded
3. **Special Cases**: Test Bowl track uses inverted time calculation (2000.0 / time)

### Concurrent Processing

#### Bounded Concurrency Pattern
- **Task Spawning**: One async task per car file
- **Semaphore**: Limits concurrent operations to 20 (bounded concurrency)
- **Error Isolation**: Individual car failures don't stop batch processing

#### Synchronization
- **Join Handles**: Waits for all parsing tasks to complete
- **Mutex Protection**: Safe concurrent access to shared BEST_CARS cache

## File Organization

### Input Files
```
├── cars_repo.json          # Car database from repository
├── tracks_repo.json        # Track definitions
├── track_names.json        # Track code → name mappings (compiled in)
├── my_cars.json           # User's car collection (game export)
└── times/                 # Individual car timing files
    ├── Ferrari_F40_1987.json
    ├── McLaren_F1_1993.json
    └── ...
```

### Output Files
```
├── best.csv              # Best cars analysis results
├── details.csv           # Detailed timing data
├── add.csv               # Cars to add to wishlist
├── remove.csv            # Cars to remove from wishlist
├── trash.csv             # Owned cars safe to remove
├── sorted.csv            # Best cars sorted by count
├── very_best.csv         # Best cars with count ≥ 10
└── wishlist.csv          # Missing cars already on wishlist
```

## Performance Characteristics

### Records Module
- **Startup Time**: Fast (uses cached JSON files)
- **Memory Usage**: Moderate (loads all timing data into memory)
- **Accuracy**: High (comprehensive dataset)
- **Update Frequency**: Manual refresh required
- **Concurrency**: Bounded at 20 simultaneous operations via semaphore

## Error Handling Strategy

### Graceful Degradation
- **Missing Files**: Continue with available data
- **Network Errors**: Log errors but don't crash
- **Parse Failures**: Use default values or skip invalid entries

### User Feedback
- **Progress Indication**: Shows fetching/download progress
- **Error Messages**: Clear descriptions of what went wrong

## Extension Points

### Adding New Tracks
1. Update `tracks_repo.json` with new track definitions
2. Add track name mapping in `track_names.json`
3. Add condition mappings in `translate_track_type()`

### Adding New Analysis Types
1. Create new output functions (similar to `print_best_cars()`)
2. Add command parsing in main function
3. Update help text and documentation

## Security Considerations

### Network Access
- **HTTPS Only**: All external requests use HTTPS
- **Certificate Validation**: Accepts invalid certificates for compatibility
- **Rate Limiting**: Respects server limits with controlled concurrency (semaphore limit of 20)

### Local File Access
- **Read Only**: No modification of game files
- **User Data**: Only reads exported collection data
- **No Persistence**: Analysis results are output-only

## Future Enhancements

### Potential Improvements
1. **Caching Layer**: Cache parsed results between runs
2. **Database Backend**: Replace in-memory HashMap with persistent storage
3. **Configuration Files**: External configuration for analysis parameters
4. **GUI Interface**: Web-based interface for non-technical users
5. **Export Formats**: Multiple output formats (JSON, XML, etc.)

### Scalability Considerations
1. **Pagination**: Handle large datasets with pagination
2. **Incremental Updates**: Only fetch changed data
3. **Compression**: Compress large timing files
4. **Streaming**: Process data without loading everything into memory