We want to build a 1-page web site similar to https://memeinator.com/ -- the donation widget needs to be on top of the page. It shall allow a user to donate ETH, USDT or USDC.

The backend used by the donation web site frontend is called delphi and it will expose a REST API to the frontend.

The dws backend consists of a postgres database and 5 services

• buck: ETH/latest crawler, checks the latest blocks for donation transactions and inserts these into the database (in state unconfirmed)
• buck: ETH/finalized crawler, checks the finalized blocks for donation transactions and confrm them, also updates the donation campaign statistics and the token price (if/as needed)
• buck: ETH/old-unconfirmed crawler, checks for donations that are older than 30 minutes but still unconfirmed, attempts to fetch the respective finalized blocks and confirm these donation transactions
• pulitzer: pulls the ETH price from 6 exchanges and inserts an average price into the database every minute
• delphi: REST API server -- only serves data from the database

The backend services are written in go -- you will thus need go on your development system. For testing purposes the postgres database can be run in a docker container i.e. you will need docker as well.

Once you have these in place you can simply run

1. go mod tidy to fetch the dependencies
2. make to build the services
3. make run_db to run a fresh database in a docker container
4. make run_pulitzer in a separate terminal
5. make run_delphi in a separate terminal
6. make run_buck_latest in a separate terminal
7. make run_buck_final in a separate terminal
8. make run_buck_old_unconfirmed in a separate terminal

All services support the -p command-line flag allowing you to set the port they are listening to. The default ports are as follows

1. all amounts are passed as strings and should be decoded to a decimal type to preserve precision

2. users may be sent to our web site via a link that contains an affiliate code e.g.

   https://tm.io/donate?afc=AivCuktyds0

   If such an affiliate code is present then it needs to be passed to the delphi backend after a donation transaction. We cannot capture it in the ethereum transaction if the latter involves calling an erc-20 smart contract -- the data property (of the ethereum transaction) holds the arguments of the function invoked on the smart contract.

3. the frontend needs to get the token price from the dsw backend upon each refresh

4. the frontend needs to get the ETH price from the dsw backend

   1. upon each refresh
   2. once a minute
   3. whenever the user presses the "donate" button and the asset he is donating is ETH

A user comes to our donation web site and connects his metamask wallet that is switched to the ethereum mainnet:

1. get the wallet address
2. call the delphi backend to get the user data associated with the wallet address
3. if the user has not donated anything the backend will return an empty json dict.

A user comes to our donation web site and connects his metamask wallet that is switched to the ethereum mainnet:

1. get the wallet address

2. call the delphi backend to get the user data associated with the wallet address

3. the data returned by the delphi backend should look similar to this:

   {
     "donations": [
       {
         "amount": "1.2345600000",
         "asset": "eth",
         "price": "0.00100",
         "status": "confirmed",
         "tokens": "1981414",
         "ts": "2023-10-21T07:38:36Z",
         "tx_hash": "0xf98c0fe5c1bf72cad294c5ba60ca5b62d3d519fe7cc71cc3cdfb064892fa90e2",
         "usd_amount": "1981.41"
       },
       {
         "amount": "0.9876540000",
         "asset": "eth",
         "price": "0.00100",
         "status": "confirmed",
         "tokens": "1586905",
         "ts": "2023-10-21T07:56:12Z",
         "tx_hash": "0x7ddb66c1be4ec06e0edd6c2f4ad8b878b2fb5b8075157f5881f0a7f35c5c7cb4",
         "usd_amount": "1586.90"
       }
     ],
     "user_data": {
       "reward": "0",
       "staked": "0",
       "status": "none",
       "tokens": "3568319",
       "total": "3568.31",
       "ts": "2023-10-21T08:28:38.744069Z"
     }
   }

   The first n-1 stanzas are the donations made by the user. The last stanza is a summary.

4. display the data above to the user

5. if he has not staked any tokens allow him to do so

6. if he has staked tokens already allow him to unstake them (takes 7 days from the time the unstaking was requested)

Display the token price and allow the user to

1. select the asset (ETH, USDT or USDC)
2. specify the amount he wants to donate

Whenever the amount changes: display the amount of tokens corresponding to the donation amount specified.

If the user is donating ETH the token amount needs to be calculated as follows:

ceiling(DA * EP / TP)

where

• DA = donation amount in ETH
• EP = ethereum price in USD
• TP = token price

If the user is donating in stable coin the formula is simpler:

ceiling(DA / TP)

After the user presses the "donate" button: construct the ethereum transaction and send it to the network.

If the user came via an affiliate code - call the delphi backend and pass the txHash and the affiliate code to it.