Lottery SMC base case scenario

[BanzaiTokyo]

Roles

• a new lottery can be started by anyone, the person becomes the lottery starter. The lottery starter gets a part of each ticket sale. Let's say the base case is 5% (in the future, the percentage could be modified by the lottery starter).
• the lottery has "the developer" the wallet or wallets that can withdraw the developer's part of the fees. I propose that the developer's fee should be hardcoded for now at 1%.
• user can buy lottery tickets. Only 1 ticket can be bought at once. The default price is 0.001 (base)Eth + the fees (5% to the lottery starter and 1% to the developer) = 0.0016 Eth
• ticket holder can buy more tickets. the number of tickets they purchased is stored in the contract
• lottery winner is a ticket owner chosen at random to collect the prize pool.

Fields

• lottery closing date (set when a lottery is created)
• lottery prize pool (incremented when a ticket is purchased)
• ticket owners array (address) where an address can appear multiple times according to the number of tickets purchased
• the winner (set by the draw)

Features

• when the closing date is reached, the lottery stops accepting bets. Anyone can initiate the draw after the closing date is reached
• The lottery starter can withdraw their fees only after the draw (it should stimulate the lottery starter to initiate the draw and pay the gas fees instead of some ticket owner)
• the draw selects the winner at random among ticket holders array by random index (because addresses may appear several times, the probability corresponding to the number of tickets purchased is achieved)
• the developer can withdraw their fees any time

[gurobokum]

Looks good

Some adds:

• Support custom creator fee
• Support custom deposits by creator

[developerisnow]

Hey @BanzaiTokyo I made some tweaks to the lottery smart contract spec to improve the structure and clarity. I reorganized the roles section, and restructured the user roles to show the hierarchy better.

I also added a "Data" section for key variables and converted the features into a checklist format. Lastly, I included a "Future Enhancements" section for potential improvements.

The goal is to make the spec more organized and developer-friendly. Let me know if you have any questions or feedback! Cheers.

[developerisnow]

Roles

• Lottery Creator: Anyone can start a new lottery and become the lottery creator. They receive a percentage of each ticket sale (default: 5%, adjustable in future versions).
• Lottery Smart Contract: The smart contract that manages the lottery, including ticket sales, prize pool, and drawing the winner.
• Lottery Factory: A smart contract or libriary that automatically creates new lottery smart contracts based on input from the lottery creator.
• Users:
  • Participants: Users who buy lottery tickets. They can purchase multiple tickets.
  • Winner: The participant chosen at random to receive the prize pool.
• Developer: The wallet(s) that receive a percentage of ticket sales as a fee (default: 1%, hardcoded for now).

Data

• closingDate: The date and time when the lottery stops accepting new tickets.
• prizePool: The total amount of Ether in the prize pool, incremented with each ticket purchase.
• ticketOwners: An array of addresses representing ticket owners, where an address can appear multiple times based on the number of tickets purchased.
• winner: The address of the participant chosen as the winner during the draw.

Features

• [x] Ticket Purchase:
  • [x] Users can buy lottery tickets at a default price of 0.001 ETH + fees (5% to the lottery creator, 1% to the developer).
  • [ ] Only one ticket can be purchased per transaction.
  • [x] The number of tickets purchased by each user is stored in the contract.
• [ ] Lottery Closure:
  • [x] The lottery stops accepting new tickets when the closing date is reached.
  • [x] Anyone can initiate the draw after the closing date.
• [ ] Draw:
  • [x] The draw selects a winner at random from the ticketOwners array, ensuring that the probability of winning corresponds to the number of tickets purchased.
• [ ] Fee Distribution:
  • [x] The lottery creator can withdraw their fees only after the draw, incentivizing them to initiate the draw and pay the gas fees.
  • [ ] The developer can withdraw their fees at any time.

Future Enhancements

• [x] Allow the lottery creator to set a custom percentage for their fee.
• [x] Allow the lottery creator to make a custom deposit
• [x] Implement a user-friendly interface for creating and participating in lotteries.
• [ ] Add support for other ERC20 tokens as the prize and ticket purchase currency. (or we already support it)
• [ ] Introduce additional lottery types, such as recurring lotteries or multi-winner lotteries.

[gurobokum]

Additional Future Enhancements

• [ ] getting random number with Chainlink VRF