# Architecture Overview

Quick reference for new developers to understand the BugPin codebase structure.

## Directory Structure

```
src/
├── server/                 # Bun + Hono backend
│   ├── routes/             # HTTP handlers only
│   ├── services/           # Business logic, validation
│   ├── database/
│   │   ├── database.ts     # SQLite connection
│   │   ├── migrations/     # SQL migration files
│   │   └── repositories/   # Data access layer
│   │       └── interfaces.ts
│   ├── storage/
│   │   └── files.ts        # File system operations
│   ├── middleware/         # Auth, validation, rate limiting
│   └── utils/
│       └── result.ts       # Result type and helpers
├── admin/                  # React admin portal
│   ├── pages/
│   ├── components/
│   ├── hooks/
│   └── api/
├── widget/                 # Preact embeddable widget
│   ├── components/
│   ├── utils/
│   └── storage/            # IndexedDB offline cache
└── shared/                 # Shared types between packages
    └── types/
```

## Tech Stack

| Component     | Technology                     |
| ------------- | ------------------------------ |
| Server        | Bun runtime, Hono framework    |
| Database      | SQLite (single file)           |
| Admin Console | React 19, Vite, TanStack Query |
| Widget        | Preact, Shadow DOM             |
| Auth          | Session-based, bcrypt          |

## Data Flow

```
Client Request
     ↓
[Middleware] → Auth, rate limiting, validation
     ↓
[Route] → Parse request, call service
     ↓
[Service] → Business logic, validation, Result<T>
     ↓
[Repository] → SQLite queries
     ↓
[Database] → data/bugpin.db
```

## Key Directories

### Server (`src/server/`)

| Directory                | Purpose                                                       |
| ------------------------ | ------------------------------------------------------------- |
| `routes/`                | HTTP request handlers. Thin layer that delegates to services. |
| `services/`              | Business logic. Returns `Result<T>` types.                    |
| `database/repositories/` | Data access. SQLite queries only.                             |
| `database/migrations/`   | SQL schema migrations.                                        |
| `storage/`               | File system operations (uploads).                             |
| `middleware/`            | Request processing (auth, validation).                        |
| `utils/`                 | Shared utilities (Result, ID generation).                     |

### Admin (`src/admin/`)

| Directory     | Purpose                                   |
| ------------- | ----------------------------------------- |
| `pages/`      | Route-level page components.              |
| `components/` | Reusable UI components.                   |
| `hooks/`      | Custom React hooks (useAuth, useReports). |
| `api/`        | API client functions.                     |

### Widget (`src/widget/`)

| Directory     | Purpose                          |
| ------------- | -------------------------------- |
| `components/` | Widget UI (button, modal, form). |
| `utils/`      | Screenshot capture, annotations. |
| `storage/`    | IndexedDB for offline queue.     |

## Widget Constraints

- Bundle size: ≤190KB gzipped (IIFE bundle, the one customers embed)
- No external runtime dependencies
- Shadow DOM for CSS isolation
- Offline-first with IndexedDB queue
- ES2020 browser target

## Runtime Data

```
data/
├── bugpin.db              # SQLite database
└── uploads/               # User files
    ├── screenshots/
    ├── attachments/
    └── branding/
```

This directory is git-ignored and created at runtime.