{"ns":"coffee","title":"Brew Bar","version":"1.0","summary":"Brew Bar is a one-page coffee ordering app. Customers click cup illustrations to add drinks, preview and edit the cart, accept an occasional lucky-day Mocha offer, pay through a short form and review past orders. The server re-prices every cart from the menu.","problem":"Ordering a few drinks should take seconds. Customers need a cart whose total is always right, an offer that is applied exactly as advertised and a checkout that refuses bad details instead of creating a broken order.","personas":[{"name":"Customer","need":"Pick drinks quickly, see an accurate total and pay without surprises."},{"name":"Cafe owner","need":"Have every order priced from the menu and promotions limited to one per order."}],"goals":["Every total shown equals the sum of menu prices and offer prices.","Orders are created only from valid buyer details.","Repeated clicks or reloads never add or lose cups by accident."],"features":[{"id":"MNU","title":"Menu and adding drinks","summary":"The menu shows nine drinks as clickable cup illustrations.","reqs":[{"id":"FR-MNU-01","weight":"Must","text":"The menu lists nine drinks with their prices, and the pay button starts at $0.00.","accept":["Espresso $10.00, Espresso Macchiato $12.00, Cappuccino $19.00, Mocha $8.00, Flat White $18.00, Americano $7.00, Cafe Latte $16.00, Espresso Con Panna $14.00, Cafe Breve $15.00.","The pay button reads \"Total: $0.00\" and the header \"cart (0)\"."]},{"id":"FR-MNU-02","weight":"Must","text":"Clicking a cup adds one of that drink and updates the total and cart count.","accept":["Cappuccino gives \"Total: $19.00\" and \"cart (1)\"; adding Espresso gives \"Total: $29.00\" and \"cart (2)\"."]},{"id":"FR-MNU-03","weight":"Could","text":"Double-clicking a drink title toggles between its English and Chinese name without changing the cart.","accept":["\"Espresso\" becomes \"特浓咖啡 $10.00\" and back to \"Espresso $10.00\"; the total stays $0.00."]},{"id":"FR-MNU-04","weight":"Could","text":"Each cup illustration shows its ingredients as layers.","accept":["Mocha shows espresso, chocolate syrup, steamed milk and whipped cream."]},{"id":"FR-MNU-05","weight":"Should","text":"Cups can be focused and added from the keyboard with Enter or Space.","accept":["Enter on the focused Espresso gives \"Total: $10.00\"; Space then gives \"Total: $20.00\"."]},{"id":"FR-MNU-06","weight":"Should","text":"When adding is slow, one click adds exactly one cup and repeated clicks while brewing add nothing.","accept":["Clicking Espresso shows \"Brewing Espresso…\" and after about 1.5 seconds \"Total: $10.00\".","Three quick clicks on Americano add one Americano: \"Total: $17.00\", \"cart (2)\"."]}]},{"id":"PRV","title":"Cart preview and cart page","summary":"The cart can be previewed by hovering the pay button and edited on a cart page.","reqs":[{"id":"FR-PRV-01","weight":"Should","text":"Hovering the pay button shows a cart preview, with + and - controls, that closes when the pointer leaves.","accept":["With Flat White and Americano the preview lists \"Flat White x 1\" and \"Americano x 1\".","\"+\" on Flat White gives \"Flat White x 2\" and \"Total: $43.00\"; \"-\" on Americano removes it and gives \"Total: $36.00\"."]},{"id":"FR-PRV-02","weight":"Must","text":"The cart page shows unit price, quantity and line total for each drink, and its total equals the pay button total.","accept":["Two Cafe Lattes and one Cafe Breve: \"Cafe Latte $16.00 x 2 $32.00\", \"Cafe Breve $15.00 x 1 $15.00\", \"Total: $47.00\"."]},{"id":"FR-PRV-03","weight":"Must","text":"\"+\" and \"-\" change a line quantity by exactly one; \"-\" on a single cup removes the line.","accept":["Two Mochas then \"-\" gives \"Mocha $8.00 x 1 $8.00\" and \"Total: $8.00\"; \"+\" twice gives \"x 3 $24.00\".","Three Mochas then \"-\" gives \"x 2 $16.00\".","\"-\" until nothing remains shows \"No coffee, go add some.\""]},{"id":"FR-PRV-04","weight":"Should","text":"\"x\" removes every cup of that drink.","accept":["Two Espressos and one Flat White: \"x\" on Espresso leaves Flat White, \"Total: $18.00\", \"cart (1)\"."]},{"id":"FR-PRV-05","weight":"Could","text":"An empty cart page shows a friendly message and no pay button.","accept":["\"No coffee, go add some.\" is shown with no \"Total\" button."]},{"id":"FR-PRV-06","weight":"Should","text":"The cart is kept for the browser tab across reloads.","accept":["One Cappuccino then a reload still shows \"Total: $19.00\" and \"cart (1)\"."]}]},{"id":"PRM","title":"Lucky-day Mocha offer","summary":"After every third cup a discounted Mocha is offered.","reqs":[{"id":"FR-PRM-01","weight":"Must","text":"After the third cup the dialog \"It's your lucky day! Get an extra cup of Mocha for $4.\" appears; accepting adds one discounted Mocha charged exactly $4.00.","accept":["Espresso, Americano and Mocha show the dialog with \"Total: $25.00\".","\"Yes, of course!\" gives \"Total: $29.00\" and \"cart (4)\"; the cart page lists \"(Discounted) Mocha\" $4.00 x 1 = $4.00.","Three Americanos plus acceptance give \"Total: $25.00\"."]},{"id":"FR-PRM-02","weight":"Should","text":"Declining the offer leaves the cart unchanged.","accept":["Three Americanos then \"Nah, I'll skip.\" gives \"Total: $21.00\" and \"cart (3)\"."]},{"id":"FR-PRM-03","weight":"Should","text":"The discounted Mocha is limited to one per order; its \"+\" is disabled and the offer is not shown again while it is in the cart.","accept":["The \"+\" on the discounted line is disabled.","Adding three more cups shows no lucky-day dialog."]}]},{"id":"PAY","title":"Checkout","summary":"A payment dialog collects name and email and creates an order.","reqs":[{"id":"FR-PAY-01","weight":"Must","text":"Paying for a cart shows a confirmation, resets the cart and records an order in history.","accept":["Cappuccino and Espresso: the pay button opens \"Payment details\" with Name, Email and a promotional-messages checkbox.","Submitting valid details shows \"Thanks for your purchase. Please check your email for payment.\" and resets the total to $0.00.","The newest order BB-1006 shows the buyer, 2 cups and $29.00."]},{"id":"FR-PAY-02","weight":"Must","text":"Name and email are required; submitting without them is refused and the dialog stays open.","accept":["Both empty: \"Name is required\" and \"Email is required\".","Name only: \"Email is required\"."]},{"id":"FR-PAY-03","weight":"Must","text":"A malformed email is refused with \"Enter a valid email address\"; the cart is kept and no order is created.","accept":["The cart still holds the Americano and no confirmation appears.","The orders page shows no new order for that buyer."]},{"id":"FR-PAY-04","weight":"Should","text":"Closing the payment dialog with the close button or the backdrop keeps the cart.","accept":["One Mocha: \"×\" closes the dialog with \"Total: $8.00\"; a click on the backdrop also closes it."]}]},{"id":"ORD","title":"Order history","summary":"Past orders are listed newest first and expand into their lines.","reqs":[{"id":"FR-ORD-01","weight":"Should","text":"Orders are listed newest first and each expands into its lines and total.","accept":["Five seeded orders BB-1005 to BB-1001 are listed; BB-1005 is Rowan Tate, $29.00.","BB-1002 shows \"Espresso $10.00 x 3 · (Discounted) Mocha $4.00 x 1\" with total $34.00."]}]},{"id":"API","title":"Server pricing","summary":"The server prices carts and checkouts from the menu.","reqs":[{"id":"FR-API-01","weight":"Must","text":"Quote and checkout compute totals from the menu, reject a stale client total and refuse more than one discounted Mocha.","accept":["Quote for 2 Mochas and 1 discounted Mocha returns 200 with total 2000 (cents).","Checkout with one Cappuccino and an expected total of 1000 returns 409 \"Prices changed — please review your cart\" with total 1900.","Quote for 2 discounted Mochas returns 422 \"Only one discounted Mocha per order\"."]}]}],"nfr":[{"id":"NFR-01","weight":"Must","text":"Prices and offers are decided by the server, never trusted from the browser.","accept":["A client total that differs from the menu price is rejected."]}],"glossary":[{"term":"Lucky-day offer","meaning":"A discounted Mocha offered after every third cup."},{"term":"Cart preview","meaning":"The list shown while hovering the pay button."}],"outOfScope":["Real payment","Email delivery"]}