-- Copyright (c) 2003-2007 ETH Zurich, Switzerland
--                    2016 The University of Sheffield, UK
-- 
-- All rights reserved.
-- 
-- Redistribution and use in source and binary forms, with or without
-- modification, are permitted provided that the following conditions are met:
-- 
-- * Redistributions of source code must retain the above copyright notice, this
--   list of conditions and the following disclaimer.
-- 
-- * Redistributions in binary form must reproduce the above copyright notice,
--   this list of conditions and the following disclaimer in the documentation
--   and/or other materials provided with the distribution.
-- 
-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
-- DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
-- FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-- DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
-- SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
-- CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
-- OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-- OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-- 
-- SPDX-License-Identifier: BSD-2-Clause
--

package ISP
--
-- Consitency
-- ==========

-- For the service ``1GB'' the free download variable should be
-- invariant and be set to 1.
context Max1GB
  inv : self.oclAsType(ISP.Service).freedownload = 1024
-- [Enc] inv : self.freedownload = 1024


-- A customer can only have a service from his service provider
context Provider
  inv onlyOfferedService: self.services->includesAll(self.customer
                             ->collect(c:Customer | c.service)->asSet())

-- If the download rate of a customer (in Surf-Record) is lower than the
-- freedownload of his service, then the amount_of_money in his bill is
-- equal to the price in the service.
context Bill
  inv: self.surfRecord.downloadRate <= self.service.freedownload
      implies self.amount = self.service.price
 
-- If the bill has not been paid for 30 days, the customer's flag active
-- will be set to false
context Customer
  inv: self.bill.send_date.durationInDays(self.bill.paid_date.today()) > 30 
       and
       self.bill.send_date.durationInDays(self.bill.paid_date) > 30
       implies not self.active 


-- 
-- 
context SurfRecord::setRate(rate:Integer):Integer
  pre: true
  post: (result = if rate > downloadRate then rate
  	         else downloadRate endif)
        and
        (rate > downloadRate implies downloadRate = rate)
	and 
        (rate <= downloadRate implies downloadRate = downloadRate@pre)

--
-- 
context Customer
-- [Enc]  inv: self.allInstances()->isUnique(self.id)
  inv: self.allInstances()->forAll(
      c1:Customer, c2:Customer | c1.id = c2.id implies c1 =c2)

--  
-- 
context Provider::reenableCustomer(c:Customer):void
  pre:   not c.active
  post:  c.active  
 
--
-- Security
-- ==========
--
--
context Customer::changeService(s:Service):Boolean
  pre perm0:  s.customer.oclAsType(oclLib.OclAny) = environment.caller.oclAsType(oclLib.OclAny) 
--   pre perm0:  s.customer  = environment.caller 

--
-- A customer can only view his own downloadrate
context SurfRecord::getRate():Integer
  pre perm1:  environment.caller.oclAsType(oclLib.OclAny) = self.customer.oclAsType(oclLib.OclAny)
--  pre perm1:  environment.caller = self.customer

--
context SurfRecord::setRate(rate:Integer):Integer
  pre perm2: environment.caller.role = 'Provider'

--
context Bill::confirm_payment():Boolean
  pre prem3: environment.caller.role = 'Provider'

endpackage