content: {-| Utility functions for cluster operations
  
  -}
  
  {-
  
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  -}
  
  module Ganeti.HTools.Cluster.Utils
    ( splitCluster
    , iMoveToJob
    , instancePriGroup
    , availableGroupNodes
    ) where
  
  import Data.Maybe (fromJust)
  import qualified Data.IntSet as IntSet
  
  import Ganeti.BasicTypes
  import qualified Ganeti.Constants as C
  import qualified Ganeti.HTools.Container as Container
  import qualified Ganeti.HTools.Instance as Instance
  import qualified Ganeti.HTools.Node as Node
  import Ganeti.HTools.Types
  import qualified Ganeti.OpCodes as OpCodes
  import Ganeti.Types (mkNonEmpty, mkNonNegative)
  
  -- | Splits a cluster into the component node groups.
  splitCluster :: Node.List -> Instance.List ->
                  [(Gdx, (Node.List, Instance.List))]
  splitCluster nl il =
    let ngroups = Node.computeGroups (Container.elems nl)
    in map (\(gdx, nodes) ->
             let nidxs = map Node.idx nodes
                 nodes' = zip nidxs nodes
                 instances = Container.filter ((`elem` nidxs) . Instance.pNode) il
             in (gdx, (Container.fromList nodes', instances))) ngroups
  
  -- | Convert a placement into a list of OpCodes (basically a job).
  iMoveToJob :: Node.List        -- ^ The node list; only used for node
                                 -- names, so any version is good
                                 -- (before or after the operation)
             -> Instance.List    -- ^ The instance list; also used for
                                 -- names only
             -> Idx              -- ^ The index of the instance being
                                 -- moved
             -> IMove            -- ^ The actual move to be described
             -> [OpCodes.OpCode] -- ^ The list of opcodes equivalent to
                                 -- the given move
  iMoveToJob nl il idx move =
    let inst = Container.find idx il
        iname = Instance.name inst
        lookNode  n = case mkNonEmpty (Container.nameOf nl n) of
                        -- FIXME: convert htools codebase to non-empty strings
                        Bad msg -> error $ "Empty node name for idx " ++
                                   show n ++ ": " ++ msg ++ "??"
                        Ok ne -> Just ne
        opF' node =
              OpCodes.OpInstanceMigrate
                { OpCodes.opInstanceName        = iname
                , OpCodes.opInstanceUuid        = Nothing
                , OpCodes.opMigrationMode       = Nothing -- default
                , OpCodes.opOldLiveMode         = Nothing -- default as well
                , OpCodes.opTargetNode          = node    -- this is drbd
                , OpCodes.opTargetNodeUuid      = Nothing
                , OpCodes.opAllowRuntimeChanges = False
                , OpCodes.opIgnoreIpolicy       = False
                , OpCodes.opMigrationCleanup    = False
                , OpCodes.opIallocator          = Nothing
                , OpCodes.opAllowFailover       = True
                , OpCodes.opIgnoreHvversions    = True
                }
        opFforced node =
          OpCodes.OpInstanceFailover
            { OpCodes.opInstanceName        = iname
            , OpCodes.opInstanceUuid        = Nothing
            , OpCodes.opShutdownTimeout     =
                fromJust $ mkNonNegative C.defaultShutdownTimeout
            , OpCodes.opIgnoreConsistency = False
            , OpCodes.opTargetNode = node
            , OpCodes.opTargetNodeUuid = Nothing
            , OpCodes.opIgnoreIpolicy = False
            , OpCodes.opIallocator = Nothing
            , OpCodes.opMigrationCleanup = False
            }
        opFForNode = if Instance.forthcoming inst then opFforced else opF'
        opF = opFForNode Nothing
        opFA n = opFForNode (lookNode n) -- not drbd
        opR n = OpCodes.OpInstanceReplaceDisks
                  { OpCodes.opInstanceName     = iname
                  , OpCodes.opInstanceUuid     = Nothing
                  , OpCodes.opEarlyRelease     = False
                  , OpCodes.opIgnoreIpolicy    = False
                  , OpCodes.opReplaceDisksMode = OpCodes.ReplaceNewSecondary
                  , OpCodes.opReplaceDisksList = []
                  , OpCodes.opRemoteNode       = lookNode n
                  , OpCodes.opRemoteNodeUuid   = Nothing
                  , OpCodes.opIallocator       = Nothing
                  }
    in case move of
         Failover -> [ opF ]
         FailoverToAny np -> [ opFA np ]
         ReplacePrimary np -> [ opF, opR np, opF ]
         ReplaceSecondary ns -> [ opR ns ]
         ReplaceAndFailover np -> [ opR np, opF ]
         FailoverAndReplace ns -> [ opF, opR ns ]
  
  -- | Computes the group of an instance per the primary node.
  instancePriGroup :: Node.List -> Instance.Instance -> Gdx
  instancePriGroup nl i =
    let pnode = Container.find (Instance.pNode i) nl
    in  Node.group pnode
  
  -- | Computes the nodes in a given group which are available for
  -- allocation.
  availableGroupNodes :: [(Gdx, [Ndx])] -- ^ Group index/node index assoc list
                      -> IntSet.IntSet  -- ^ Nodes that are excluded
                      -> Gdx            -- ^ The group for which we
                                        -- query the nodes
                      -> Result [Ndx]   -- ^ List of available node indices
  availableGroupNodes group_nodes excl_ndx gdx = do
    local_nodes <- maybe (Bad $ "Can't find group with index " ++ show gdx)
                   Ok (lookup gdx group_nodes)
    let avail_nodes = filter (not . flip IntSet.member excl_ndx) local_nodes
    return avail_nodes
  
  