User Story: Buy a ticket for an event with offer safety

[katelynsills]

Story

As a user, I want to be able to buy a ticket to an event and have it be protected by offer safety. I do not want to have to specify things that are not important to me, like a seat number.

Status

A user hoping to purchase a ticket to an event must ask the contract or another user for a list of available tickets, and then perform a search among the tickets available to find the ones they want to buy. When the full list is available, this is very awkward. When the full list isn't available, the situation is very bad: the user cannot be protected by offer safety for their purchase of the tickets, because they don't know enough about the tickets to specify what they want.

Details

See test-sellTickets.js for this particular example.

The contract has a function getAvailableItems:

agoric-sdk/packages/zoe/test/unitTests/contracts/test-sellTickets.js

Lines 203 to 205 in 0f02d52

	const availableTickets = await E(
	ticketSalesPublicFacet,
	).getAvailableItems();

Then the user must search for the tickets they want:

agoric-sdk/packages/zoe/test/unitTests/contracts/test-sellTickets.js

Lines 225 to 230 in 0f02d52

	// find the value corresponding to ticket #1
	const ticket1Value = availableTickets.value.find(
	ticket => ticket.number === 1,
	);
	// make the corresponding amount
	const ticket1Amount = ticketAmountMath.make(harden([ticket1Value]));

Then the user can actually make a proposal and get offer safety for the tickets they want:

agoric-sdk/packages/zoe/test/unitTests/contracts/test-sellTickets.js

Lines 232 to 235 in 0f02d52

	const aliceProposal = harden({
	give: { Money: terms.pricePerItem },
	want: { Items: ticket1Amount },
	});

Next Steps

Please see the Amount Patterns Implementation Plan issue