{-| Parsing data from a simulated description of the cluster.

This module holds the code for parsing a cluster description.

-}

{-

Copyright (C) 2009, 2010, 2011, 2012 Google Inc.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301, USA.

-}

module Ganeti.HTools.Backend.Simu
  ( loadData
  , parseData
  ) where

import Control.Monad (mplus, zipWithM)
import Text.Printf (printf)

import Ganeti.BasicTypes
import Ganeti.Utils
import Ganeti.HTools.Types
import Ganeti.HTools.Loader
import qualified Ganeti.HTools.Container as Container
import qualified Ganeti.HTools.Group as Group
import qualified Ganeti.HTools.Node as Node

-- | Parse a shortened policy string (for command line usage).
apolAbbrev :: String -> Result AllocPolicy
apolAbbrev c | c == "p"  = return AllocPreferred
             | c == "a"  = return AllocLastResort
             | c == "u"  = return AllocUnallocable
             | otherwise = fail $ "Cannot parse AllocPolicy abbreviation '"
                           ++ c ++ "'"

-- | Parse the string description into nodes.
parseDesc :: String -> [String]
          -> Result (AllocPolicy, Int, Int, Int, Int, Int)
parseDesc _ [a, n, d, m, c, s] = do
  apol <- allocPolicyFromRaw a `mplus` apolAbbrev a
  ncount <- tryRead "node count" n
  disk <- annotateResult "disk size" (parseUnit d)
  mem <- annotateResult "memory size" (parseUnit m)
  cpu <- tryRead "cpu count" c
  spindles <- tryRead "spindles" s
  return (apol, ncount, disk, mem, cpu, spindles)

parseDesc desc [a, n, d, m, c] = parseDesc desc [a, n, d, m, c, "1"]

parseDesc desc es =
  fail $ printf
         "Invalid cluster specification, expected 6 comma-separated\
         \ sections (allocation policy, node count, disk size,\
         \ memory size, number of CPUs, spindles) but got %d: '%s'"
         (length es) desc

-- | Creates a node group with the given specifications.
createGroup :: Int    -- ^ The group index
            -> String -- ^ The group specification
            -> Result (Group.Group, [Node.Node])
createGroup grpIndex spec = do
  (apol, ncount, disk, mem, cpu, spindles) <- parseDesc spec $
                                              sepSplit ',' spec
  let nodes = map (\idx ->
                     Node.create (printf "node-%02d-%03d" grpIndex idx)
                           (fromIntegral mem) 0 mem
                           (fromIntegral disk) disk
                           (fromIntegral cpu) False spindles grpIndex
                  ) [1..ncount]
      grp = Group.create (printf "group-%02d" grpIndex)
            (printf "fake-uuid-%02d" grpIndex) apol defIPolicy []
  return (Group.setIdx grp grpIndex, nodes)

-- | Builds the cluster data from node\/instance files.
parseData :: [String] -- ^ Cluster description in text format
          -> Result ClusterData
parseData ndata = do
  grpNodeData <- zipWithM createGroup [1..] ndata
  let (groups, nodes) = unzip grpNodeData
      nodes' = concat nodes
  let ktn = map (\(idx, n) -> (idx, Node.setIdx n idx))
            $ zip [1..] nodes'
      ktg = map (\g -> (Group.idx g, g)) groups
  return (ClusterData (Container.fromList ktg)
                      (Container.fromList ktn) Container.empty [] defIPolicy)

-- | Builds the cluster data from node\/instance files.
loadData :: [String] -- ^ Cluster description in text format
         -> IO (Result ClusterData)
loadData = -- IO monad, just for consistency with the other loaders
  return . parseData