// ============================================================================
// 083 — Inventory Management
// ============================================================================
// Track products, quantities, and stock levels.
//
// Run:   soma run 083_inventory.cell demo
// Expect:
//   Stocked: Widget x100
//   Stocked: Gadget x50
//   Stocked: Doohickey x200
//   Sold 30 Widgets
//   === Inventory Report ===
//   Widget: 70 units ($699.30 value)
//   Gadget: 50 units ($999.50 value)
//   Doohickey: 200 units ($998.00 value)
//   Low stock items: 0

cell Inventory {

    memory {
        products: Map<String, String> [persistent, consistent]
        stock: Map<String, Int> [persistent, consistent]
    }

    on add_product(name: String, price: Float, qty: Int) {
        let product = map("name", name, "price", price)
        products.set(name, to_json(product))
        stock.set(name, qty)
        return map("name", name, "qty", qty)
    }

    on sell(name: String, qty: Int) {
        let current = stock.get(name)
        if current == () {
            return map("error", "product not found")
        }
        if current < qty {
            return map("error", "insufficient stock")
        }
        stock.set(name, current - qty)
        return map("name", name, "remaining", current - qty)
    }

    on report() {
        let keys = products.keys()
        let items = list()
        for key in keys {
            let product = from_json(products.get(key))
            let qty = stock.get(key)
            let value = product.price * to_float(qty)
            items = list(items, map("name", key, "qty", qty, "value", value))
        }
        return items
    }

    on demo() {
        add_product("Widget", 9.99, 100)
        print("Stocked: Widget x100")
        add_product("Gadget", 19.99, 50)
        print("Stocked: Gadget x50")
        add_product("Doohickey", 4.99, 200)
        print("Stocked: Doohickey x200")

        sell("Widget", 30)
        print("Sold 30 Widgets")

        let items = report()
        print("=== Inventory Report ===")
        for item in items {
            print("{item.name}: {item.qty} units (${item.value} value)")
        }

        // Check low stock (below 20)
        let low = items |> filter_by("qty", "<", 20)
        let low_count = low.length
        print("Low stock items: {low_count}")

        return "done"
    }
}