Full Application: Product Catalog with State Machine

100_full_app.cell

// ============================================================================
// 100 — Full Application: Product Catalog with State Machine
// ============================================================================
// The capstone example: combines cells, state machines, pipelines,
// memory, tests, and HTML rendering in one file.
//
// Run:   soma run 100_full_app.cell demo
// Expect:
//   === Product Catalog ===
//   Added: Laptop ($999)
//   Added: Phone ($699)
//   Added: Tablet ($449)
//   Added: Watch ($299)
//   Added: Earbuds ($149)
//   Published Laptop
//   Published Phone
//   Published Tablet
//   === Published Products ===
//   Laptop: $999
//   Phone: $699
//   Tablet: $449
//   === Analytics ===
//   Total value: 2147
//   Average price: 715
//   Most expensive: Laptop ($999)
//
// Run:   soma test 100_full_app.cell
// Expect: All tests pass

cell ProductCatalog {

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

    // Product lifecycle state machine
    state product_status {
        initial: draft

        draft -> published
        published -> archived
        archived -> published      // can re-publish
        * -> deleted
    }

    on add_product(name: String, price: Int, category: String) {
        let current = meta.get("next_id")
        if current == () {
            meta.set("next_id", 1)
        }
        let id = meta.get("next_id")
        meta.set("next_id", id + 1)
        let id_str = to_string(id)

        let product = map("id", id, "name", name, "price", price, "category", category)
        products.set(id_str, to_json(product))
        status.set(id_str, "draft")
        return product
    }

    on publish(id: String) {
        return transition(id, "published")
    }

    on archive(id: String) {
        return transition(id, "archived")
    }

    on get_published() {
        let keys = products.keys()
        let result = list()
        for key in keys {
            let st = status.get(key)
            if st == "published" {
                result = list(result, from_json(products.get(key)))
            }
        }
        return result |> sort_by("price", "desc")
    }

    on get_all() {
        let keys = products.keys()
        let result = list()
        for key in keys {
            result = list(result, from_json(products.get(key)))
        }
        return result
    }

    on demo() {
        print("=== Product Catalog ===")

        let p1 = add_product("Laptop", 999, "Electronics")
        print("Added: {p1.name} (${p1.price})")

        let p2 = add_product("Phone", 699, "Electronics")
        print("Added: {p2.name} (${p2.price})")

        let p3 = add_product("Tablet", 449, "Electronics")
        print("Added: {p3.name} (${p3.price})")

        let p4 = add_product("Watch", 299, "Accessories")
        print("Added: {p4.name} (${p4.price})")

        let p5 = add_product("Earbuds", 149, "Accessories")
        print("Added: {p5.name} (${p5.price})")

        // Publish some products
        publish("1")
        print("Published Laptop")
        publish("2")
        print("Published Phone")
        publish("3")
        print("Published Tablet")

        // Show published only
        let published = get_published()
        print("=== Published Products ===")
        for p in published {
            print("{p.name}: ${p.price}")
        }

        // Analytics on published products
        let total = published |> sum_by("price")
        let avg = published |> avg_by("price")
        let most = published |> max_by("price")

        print("=== Analytics ===")
        print("Total value: {total}")
        print("Average price: {avg}")
        print("Most expensive: {most.name} (${most.price})")

        return "done"
    }
}

// Helper for tests
cell MathHelper {
    on double(n: Int) {
        return n * 2
    }

    on is_positive(n: Int) {
        if n > 0 {
            return true
        }
        return false
    }
}

// Tests
cell test CatalogTests {
    rules {
        assert double(5) == 10
        assert double(0) == 0
        assert is_positive(1) == true
        assert is_positive(0) == false
    }
}