# Architecture

## Tech Stack

| Component | Technology |
|-----------|------------|
| Backend | Go 1.22+ (go.mod: 1.24.0) |
| Web framework | Gin |
| ORM | GORM |
| Database | MariaDB 11 |
| Frontend | htmx + Tailwind CDN (no build step) |
| Excel | excelize |
| Go module | `git.mchus.pro/mchus/priceforge` |

---

## Directory Structure

```
PriceForge/
├── bible/                    # Architectural documentation (you are here)
├── bin/                      # Build output
├── cmd/
│   ├── pfs/                  # Main server (main.go ~749 lines)
│   ├── cron/                 # Cron job runner
│   ├── importer/             # Stock import utility
│   ├── migrate/              # Migration tool
│   └── migrate_ops_projects/ # Legacy project migrator
├── data/                     # Data files
├── internal/                 # Application code
│   ├── appmeta/              # Application metadata
│   ├── appstate/             # Global state
│   ├── config/               # YAML config loading
│   ├── db/                   # DB connection, connection pool
│   ├── dbutil/               # DB utilities
│   ├── handlers/             # HTTP handlers (7 files)
│   ├── localdb/              # SQLite for local settings
│   ├── lotmatch/             # LOT mapping resolver
│   ├── middleware/           # HTTP middleware
│   ├── models/               # GORM models and migrations
│   ├── repository/           # Data access layer (11 files)
│   ├── services/             # Business logic
│   │   ├── alerts/           # Alert service
│   │   ├── pricelist/        # Pricelist service
│   │   ├── pricing/          # Price calculation
│   │   ├── sync/             # Sync (diagnostics only)
│   │   ├── stock_import.go   # Stock file import
│   │   ├── vendor_mapping.go # Vendor mapping service
│   │   └── component.go      # Component service
│   ├── tasks/                # Background Task Manager
│   └── warehouse/            # Warehouse price calculation
├── migrations/               # SQL migrations (25 files)
├── scripts/                  # Build and release scripts
├── web/
│   ├── static/               # app.css (Tailwind)
│   └── templates/            # HTML templates (9 files)
├── CLAUDE.md                 # AI agent instructions
├── README.md                 # Quick start
└── todo.md                   # Operational task list
```

---

## Application Layers (3-tier)

```
HTTP Request
    │
    ▼
┌─────────────┐
│  Handlers   │  internal/handlers/   — request parsing, validation, response
└──────┬──────┘
       │
       ▼
┌─────────────┐
│  Services   │  internal/services/   — business logic, orchestration
└──────┬──────┘
       │
       ▼
┌─────────────┐
│ Repository  │  internal/repository/ — SQL queries via GORM
└──────┬──────┘
       │
       ▼
   MariaDB 11
```

---

## Key Modules

### internal/handlers/ (7 files)

| File | Purpose |
|------|---------|
| `web.go` | Page rendering: Index, Lot, AdminPricing, Pricelists, VendorMappings |
| `component.go` | Component list and detail endpoints |
| `pricing.go` | Pricing admin: stats, components, recalc, stock, vendor mappings, alerts |
| `pricelist.go` | Pricelist CRUD and CSV export |
| `setup.go` | DB connection setup and test |
| `sync.go` | Sync diagnostic endpoints |

(6 files; `sync_readiness_test.go` is a test file)

### internal/services/

| File/dir | Purpose |
|----------|---------|
| `pricelist/` | Create Estimate, Warehouse, Competitor pricelists |
| `pricing/` | Price calc: median, weighted_median, coefficients |
| `alerts/` | Alert generation (price staleness, demand) |
| `stock_import.go` | Import .mxl/.xlsx, seen-tracking, batch processing |
| `vendor_mapping.go` | Resolve partnumber → LOT, bundles, ignore |
| `component.go` | Component listing and search |

### internal/warehouse/

`snapshot.go` — warehouse pricelist creation: weighted average, bundle expansion, allocation.

### internal/lotmatch/

`matcher.go` — vendor partnumber → LOT resolver:
1. Exact match `(vendor, partnumber)`
2. Fallback: `(vendor='', partnumber)`

### internal/tasks/

Task Manager: Submit, status polling, task types. See [background-tasks.md](background-tasks.md).

---

## HTML Templates (web/templates/)

| Template | Route | Purpose |
|----------|-------|---------|
| `base.html` | — | Layout, navigation |
| `admin_pricing.html` | `/admin/pricing` | Tabs: Estimate, Warehouse, Alerts |
| `lot.html` | `/lot` | Tabs: LOT components, Mappings |
| `pricelists.html` | `/pricelists` | Pricelist listing |
| `pricelist_detail.html` | `/pricelists/:id` | Pricelist detail view |
| `vendor_mappings.html` | `/vendor-mappings` | Vendor mapping UI |
| `components_list.html` | `/partials/components` | Components partial |
| `setup.html` | `/setup` | DB connection setup |
| `sync_status.html` | partial | Online/offline indicator |

---

## Navigation (base.html)

```
LOT              → /lot
Pricing Admin    → /admin/pricing
Settings         → /setup
```

Configurator, projects, and export links must **not** appear in the menu.

---

## Database

- **Primary**: MariaDB 11 (all operational data)
- **Local**: SQLite (only app settings and technical data; not used in `pfs` runtime)
- **Migrations**: `migrations/` — 25 SQL files, applied automatically on startup

### Key Tables

| Table | Purpose |
|-------|---------|
| `lot` | Components / articles (primary) |
| `qt_lot_metadata` | Component price metadata |
| `qt_pricelist_items` | Pricelist item rows |
| `stock_log` | Stock import data |
| `lot_partnumbers` | partnumber → LOT mappings (canonical contract) |
| `qt_lot_bundles` | Bundle definitions |
| `qt_lot_bundle_items` | Bundle composition: `(bundle_lot_name, lot_name, qty)` |
| `qt_vendor_partnumber_seen` | Seen registry (unique by `partnumber`) + `is_ignored` flag |

---

## Startup Flow

1. Parse flags (`--config`, `--migrate`, `--version`)
2. Load `config.yaml`
3. **Fail-fast**: connect to MariaDB; exit on failure
4. Apply SQL migrations
5. Start Gin router on `host:port`
6. Auto-open browser (if loopback address)