-- network stub
-- richard buckland
-- task 2, comp1711 2003 s1
-- ver 0.2  17 April 2003

module Network (
   Network,
   makeNetwork,
   nextTick, sendCommands,
   getLights, getProfit, getTicks,
   isAccident, isUnsafe, getMessages
   ) where

import ThomasLib

makeNetwork  :: TrackData -> [(Train, Track)] ->
                Market -> [Speed] -> Network
   -- contruct a network simulator using:
   -- *the track specified by TrackData
   -- *the trains specified by the (Train,Track) pairs,
   --   each train will start at position 0 on a
   --   Simple track, facing in the direction from
   --   'From' to 'To'.
   -- *The source/destinations/prices for the goods
   --   carried by the trucks
   -- *the speeds of the trains for the simulation.
   --   The first speed in the list is the tick 1 speed for
   --   the first train, then the tick 1 speed for the
   --   second train, .. then the tick 2 speed for the first
   --   train, and so on.  If the list is finite then, when
   --   it is exhausted, start again from the beginning.
   --
nextTick     :: Network -> Network
   -- simulate the network one tick.  Move each train
   -- the distance determined by their next speed value.

sendCommands :: Network -> [Command] -> Network
   -- change the network by processing a sequence of commands
   -- from the fat controllers control panel.

getLights    :: Network -> [On]
   -- return the current status of the lights on the Fat
   -- Controller's control panel.

getTicks     :: Network -> Int
   -- return the number of ticks since the simulation started.

--------------------
-- function below for bonus marks

-- implement the following function if you have time
-- otherwise just leave it = niy


getProfit    :: Network -> [Profit]
   -- return the current profit for each train.  This equals
   -- the profit obtained for past delivery of goods less
   -- a running cost of 1.0 per tick for each tick the train
   -- is not stopped.


--------------------
-- functions below
-- not needed in task2: leave them = niy
-- to be implemented in project

isAccident   :: Network -> Bool
   -- True if two trains are on the same track (collision)
   -- OR
   -- if a command was issued in the current tick for a track
   -- on which there is a train (switching a track while a train
   -- is on it)

isUnsafe     :: Network -> Bool
   -- True if controls cannot be used to prevent a future accident
   -- with 100% certainty (under the conservative assumption that
   -- trains can travel at any speed.)


getMessages  :: Network -> [Message]
   -- extension - whenever the network is detected to be unsafe or when
   -- an accident occurs a message string (in a format to be
   -- provided) is to be added to the list of safety messages.  This function
   -- returns the entire list (useful for debugging)


--------------------------------------------------------------------
-- Implementation
--------------------------------------------------------------------

--
data Network =     -- you may change lines below here only
   YourOwnDefinitionHere
   deriving (Show)

-- define the type to be whatever you like, but it MUST be a data
-- type - not a type synonym
-- you may derive Show etc for debugging - but comment it
-- out when submitting
--

niy = error "Not Implemented Yet"

makeNetwork _ _ _ _ = niy

nextTick            = niy

sendCommands _ _    = niy

getLights _         = niy

getProfit _         = niy

getTicks _          = niy

isAccident _        = niy

isUnsafe _          = niy

getMessages _       = niy