--[[
      MCNET Bank Server Software
                      Version 0.1
]]

--[[
  Request Format

  local quest = {
     requestType (auth, trans, create),
     requestAction (deposit, withdraw),
     accountName,
     accountPin,
     additionalParameter (amount)
  }

  The server will respond with either
  true (fuck you) or false (fuck you too)
]]

--Variables

local trustedClients = {}

--Functions

function isTrustedClient(id)
          for i = 1, table.getn(trustedClients) do
                    if (id == trustedClients[i]) then
                              return true
                    end
          end
          return false
end

function genAccountName(accountName)
	return "/accounts/" .. accountName
end

function getAccountInfo(accountName)
          if (fs.exists(accountName)) then
                    local account = fs.open(genAccountName(accountName), "r")
                    if (account == nil) then return nil end

                    local pin = account.readLine()
                    local balance = account.readLine()
                    account.close()

                    return pin, balance
          end

          return nil
end

function updateAccountInfo(accountName, pin, balance)
          if (fs.exists(accountName)) then
                    local account = fs.open(genAccountName(accountName), "w")
                    if (account == nil) then return false end

                    account.writeLine(pin)
                    account.writeLine(balance)
                    account.flush()
                    account.close()

                    return true
          end

          return false
end

function verifyPin(accountName, userPin)
          pin, balance = getAccountInfo(accountName)
          return (pin == userPin)
end

function deposit(accountName, userPin, amount)
          if (verifyPin(accountName, userPin)) then
                    pin, balance = getAccountInfo(genAccountName(accountName))
                    updateAccountInfo(accountName, userPin, balance + amount)

                    return true
          end

          return false
end

function withdraw(accountName, userPin, amount)
          pin, balance = getAccountInfo(accountName)
          if (balance < amount) then
                    return false
          end

          return deposit(accountName, userPin, -1 * amount)
end

function createAccount(accountName, userPin)
	if (fs.exists(genAccountName(accountName))) then
		return false
	end

	local acnt = fs.open(genAccountName(accountName), "w")
	acnt.close();

	return updateAccountInfo(accountName, userPin, 0)
end

--The Actual Shit

while true do
    id, strRequest = rednet.receive()
    request = textutils.unserialize(strRequest)

    if (not request == nil and isTrustedClient(id)) then
        if (table.getn(request) == 5) then
            if (request[1] == "auth") then
                if (verifyPin(request[3], request[4])) then
                    rednet.send(id, "true")
                else
                    rednet.send(id, "false")
                end
            end

			if (request[1] == "trans") then

                local accountName = request[3]
                local accountPin = request[4]

                if (not verifyPin(accountName, accountPin)) then
					rednet.send(id, "false")
				else
					if (request[2] == "deposit") then
						deposit(accountName, accountName, accountPin, request[5])
					end

					if (request[2] == "withdraw") then
						if (withdraw(accountName, accountPin, request[5])) then
							rednet.send(id, "true")
						end
						rednet.send(id, "false")
					end
				end
            end

            if (request[1] == "create") then
            	local accountName = request[3]
            	local accountPin = request[4]

            	if (createAccount(accountName, accountPin)) then
            		rednet.send(id, "true")
            	else
            		rednet.send(id, "false")
            	end
            end
        end
    end
end