# mutuala - subcurrency
# We want to issue a currency that reduces in value as you store it through negative interest.
# That negative interest would be stored in a commons account. It's like the p2p version of a
# capital tax
# the same things goes for transactions - you pay as you use the currency. However, the more
# you pay, the more you get to say about what the tax is used for
# each participant can propose a recipient for a payout to be made out of the commons account,
# others can vote on it by awarding it tax_credits.
# TODO should proposal have expiration timestamp?, after which the tax_credits are refunded
# TODO multiple proposals can take more credits that available in the Commons, how to handle this
# TODO how to handle lost accounts, after which no longer possible to get 2/3 majority
shared:
COMMONS = 42
ADMIN = 666
CAPITAL_TAX_PER_DAY = 7305 # 5% per year
PAYMENT_TAX = 20 # 5%
ACCOUNT_LIST_OFFSET = 2^160
ACCOUNT_MAP_OFFSET = 2^161
PROPOSAL_LIST_OFFSET = 2^162
PROPOSAL_MAP_OFFSET = 2^163
init:
contract.storage[ADMIN] = msg.sender
contract.storage[ACCOUNT_LIST_OFFSET - 1] = 1
contract.storage[ACCOUNT_LIST_OFFSET] = msg.sender
contract.storage[ACCOUNT_MAP_OFFSET + msg.sender] = 10^12
contract.storage[ACCOUNT_MAP_OFFSET + msg.sender + 1] = block.timestamp
# contract.storage[COMMONS] = balance commons
# contract.storage[ACCOUNT_LIST_OFFSET - 1] = number of accounts
# contract.storage[ACCOUNT_LIST_OFFSET + n] = account n
# contract.storage[PROPOSAL_LIST_OFFSET - 1] contains the number of proposals
# contract.storage[PROPOSAL_LIST_OFFSET + n] = proposal n
# per account:
# contract.storage[ACCOUNT_MAP_OFFSET + account] = balance
# contract.storage[ACCOUNT_MAP_OFFSET + account+1] = timestamp_last_transaction
# contract.storage[ACCOUNT_MAP_OFFSET + account+2] = tax_credits
# per proposal:
# contract.storage[PROPOSAL_MAP_OFFSET + proposal_id] = recipient
# contract.storage[PROPOSAL_MAP_OFFSET + proposal_id+1] = amount
# contract.storage[PROPOSAL_MAP_OFFSET + proposal_id+2] = total vote credits
code:
if msg.data[0] == "suicide" and msg.sender == contract.storage[ADMIN]:
suicide(msg.sender)
elif msg.data[0] == "balance":
addr = msg.data[1]
return(contract.storage[ACCOUNT_MAP_OFFSET + addr])
elif msg.data[0] == "pay":
from = msg.sender
fromvalue = contract.storage[ACCOUNT_MAP_OFFSET + from]
to = msg.data[1]
if to == 0 or to >= 2^160:
return([0, "invalid address"], 2)
value = msg.data[2]
tax = value / PAYMENT_TAX
if fromvalue >= value + tax:
contract.storage[ACCOUNT_MAP_OFFSET + from] = fromvalue - (value + tax)
contract.storage[ACCOUNT_MAP_OFFSET + to] += value
# tax
contract.storage[COMMONS] += tax
contract.storage[ACCOUNT_MAP_OFFSET + from + 2] += tax
# check timestamp field to see if target account exists
if contract.storage[ACCOUNT_MAP_OFFSET + to + 1] == 0:
# register new account
nr_accounts = contract.storage[ACCOUNT_LIST_OFFSET - 1]
contract.storage[ACCOUNT_LIST_OFFSET + nr_accounts] = to
contract.storage[ACCOUNT_LIST_OFFSET - 1] += 1
contract.storage[ACCOUNT_MAP_OFFSET + to + 1] = block.timestamp
return(1)
else:
return([0, "insufficient balance"], 2)
elif msg.data[0] == "hash":
proposal_id = sha3(msg.data[1])
return(proposal_id)
elif msg.data[0] == "propose":
from = msg.sender
# check if sender has an account and has tax credits
if contract.storage[ACCOUNT_MAP_OFFSET + from + 2] == 0:
return([0, "sender has no tax credits"], 2)
proposal_id = sha3(msg.data[1])
# check if proposal doesn't already exist
if contract.storage[PROPOSAL_MAP_OFFSET + proposal_id]:
return([0, "proposal already exists"])
to = msg.data[2]
# check if recipient is a valid address and has an account (with timestamp)
if to == 0 or to >= 2^160:
return([0, "invalid address"], 2)
if contract.storage[ACCOUNT_MAP_OFFSET + to + 1] == 0:
return([0, "invalid to account"], 2)
value = msg.data[3]
# check if there is enough money in the commons account
if value > contract.storage[COMMONS]:
return([0, "not enough credits in commons"], 2)
# record proposal in list
nr_proposals = contract.storage[PROPOSAL_LIST_OFFSET - 1]
contract.storage[PROPOSAL_LIST_OFFSET + nr_proposals] = proposal_id
contract.storage[PROPOSAL_LIST_OFFSET - 1] += 1
# record proposal in map
contract.storage[PROPOSAL_MAP_OFFSET + proposal_id] = to
contract.storage[PROPOSAL_MAP_OFFSET + proposal_id + 1] = value
return(proposal_id)
elif msg.data[0] == "vote":
from = msg.sender
proposal_id = sha3(msg.data[1])
value = msg.data[2]
# check if sender has an account and has tax credits
if value < contract.storage[ACCOUNT_MAP_OFFSET + from + 2]:
return([0, "sender doesn't have enough tax credits"], 2)
# check if proposal exist
if contract.storage[PROPOSAL_MAP_OFFSET + proposal_id] == 0:
return([0, "proposal doesn't exist"], 2)
# increase votes
contract.storage[PROPOSAL_MAP_OFFSET + proposal_id + 2] += value
# withdraw tax credits
contract.storage[ACCOUNT_MAP_OFFSET + from + 2] -= value
# did we reach 2/3 threshold?
if contract.storage[PROPOSAL_MAP_OFFSET + proposal_id + 2] >= contract.storage[COMMONS] * 2 / 3:
# got majority
to = contract.storage[PROPOSAL_MAP_OFFSET + proposal_id]
amount = contract.storage[PROPOSAL_MAP_OFFSET + proposal_id + 1]
# adjust balances
contract.storage[ACCOUNT_MAP_OFFSET + to] += amount
contract.storage[COMMONS] -= amount
# reset proposal
contract.storage[PROPOSAL_MAP_OFFSET + proposal_id] = 0
contract.storage[PROPOSAL_MAP_OFFSET + proposal_id + 1] = 0
contract.storage[PROPOSAL_MAP_OFFSET + proposal_id + 2] = 0
return(1)
return(proposal_id)
elif msg.data[0] == "tick":
nr_accounts = contract.storage[ACCOUNT_LIST_OFFSET - 1]
account_idx = 0
tax_paid = 0
# process all accounts and see if they have to pay their daily capital tax
while account_idx < nr_accounts:
cur_account = contract.storage[ACCOUNT_LIST_OFFSET + account_idx]
last_timestamp = contract.storage[ACCOUNT_MAP_OFFSET + cur_account + 1]
time_diff = block.timestamp - last_timestamp
if time_diff >= 86400:
tax_days = time_diff / 86400
balance = contract.storage[ACCOUNT_MAP_OFFSET + cur_account]
tax = tax_days * (balance / CAPITAL_TAX_PER_DAY)
if tax > 0:
# charge capital tax, but give tax credits in return
contract.storage[ACCOUNT_MAP_OFFSET + cur_account] -= tax
contract.storage[ACCOUNT_MAP_OFFSET + cur_account + 1] += tax_days * 86400
contract.storage[ACCOUNT_MAP_OFFSET + cur_account + 2] += tax
contract.storage[COMMONS] += tax
tax_paid += 1
account_idx += 1
return(tax_paid) # how many accounts did we charge tax on
else:
return([0, "unknown command"], 2)
