ArbiterRegistry

# Arbiter registry
# There is a minimum 1 ETH fee to register, though registrees are free
# to pay fees above this. In the dapp, registrations will be sorted by
# the total fee paid, although an exponential decay of 50% per month
# will be added.

data arbiters[2**160](totFee, lastPaid, description[10])
data addressList[2**100]
data nextAddress
event NewRegistry(addr:address:indexed, amount)
event FeePaid(addr:address:indexed, amount, newTotal)
event NewDescription(addr:address:indexed, description:str)

PERIOD = 86400 * 30 * 1000 / 693
MINFEE = 10**15
MAX_PERIOD_BEFORE_EXPIRY = 86400 * 365

def const exp_decay(val, i):
    while i > PERIOD / 2:
        val = val * 6065306 / 10000000
        i -= PERIOD / 2
    return val - val * i / PERIOD + val * i**2 / PERIOD**2 / 2 - val * i**3 / PERIOD**3 / 6

def register():
    # Minimum entry fee: 1 ETH
    if self.arbiters[msg.sender].totFee + msg.value < MINFEE:
        send(msg.sender, msg.value)
        return(0:bool)
    if self.arbiters[msg.sender].totFee == 0:
        self.addressList[self.nextAddress] = msg.sender
        self.nextAddress += 1
        self.arbiters[msg.sender].totFee = msg.value
        log(type=NewRegistry, msg.sender, msg.value)
        log(type=FeePaid, msg.sender, msg.value, msg.value)
    else:
        timediff = block.timestamp - self.arbiters[msg.sender].lastPaid
        self.arbiters[msg.sender].totFee = self.exp_decay(self.arbiters[msg.sender].totFee, timediff) + msg.value
        log(type=FeePaid, msg.sender, msg.value, self.arbiters[msg.sender].totFee)
    self.arbiters[msg.sender].lastPaid = block.timestamp
    return(1:bool)

def set_description(description:str):
    # Max length: 288 chars; also, you need to be registered before you can set description
    if len(description) > 288 or not self.arbiters[msg.sender].totFee:
        return(0:bool)
    self.arbiters[msg.sender].description[0] = len(description)
    i = 0
    while i * 32 < len(description):
        self.arbiters[msg.sender].description[i + 1] = description[i]
        i += 1
    log(type=NewDescription, msg.sender, description)
    return(1:bool)

def const get_tot_fee(account:address):
    tdiff = block.timestamp - self.arbiters[account].lastPaid
    if (tdiff > MAX_PERIOD_BEFORE_EXPIRY):
        return(0)
    return(self.exp_decay(self.arbiters[account].totFee, tdiff))

def const get_description(account:address):
    buffer = alloc(320)
    i = 0
    buffer[0] = self.arbiters[account].description[0]
    while i * 32 < buffer[0]:
        buffer[i + 1] = self.arbiters[account].description[i + 1]
        i += 1
    return(buffer + 32:str)

def const get_addresses(startIndex):
    o = array(50)
    i = 0
    MAX = min(self.nextAddress - startIndex, 50)
    while i < MAX:
        o[i] = self.addressList[startIndex + i]
        i += 1
    o[-1] = i
    return(o:address[])

# The ethereum foundation can withdraw registration fees
def withdraw():
    send(0xde0b295669a9fd93d5f28d9ec85e40f4cb697bae, self.balance)