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{-| Module abstracting the node and instance container implementation.
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This is currently implemented on top of an 'IntMap', which seems to
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give the best performance for our workload.
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-}
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{-
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Copyright (C) 2009 Google Inc.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301, USA.
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-}
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module Ganeti.HTools.Container
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    (
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     -- * Types
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     Container
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    , Key
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     -- * Creation
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    , empty
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    , fromAssocList
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     -- * Query
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    , size
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    , find
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     -- * Update
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    , add
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    , addTwo
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    , remove
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    , IntMap.map
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    , IntMap.mapAccum
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    -- * Conversion
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    , elems
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    , keys
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    -- * Element functions
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    , nameOf
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    , maxNameLen
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    , findByName
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    ) where
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import qualified Data.IntMap as IntMap
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import qualified Ganeti.HTools.Types as T
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type Key = IntMap.Key
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type Container = IntMap.IntMap
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-- | Create an empty container.
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empty :: Container a
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empty = IntMap.empty
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-- | Returns the number of elements in the map.
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size :: Container a -> Int
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size = IntMap.size
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-- | Locate a key in the map (must exist).
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find :: Key -> Container a -> a
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find k = (IntMap.! k)
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-- | Add or update one element to the map.
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add :: Key -> a -> Container a -> Container a
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add = IntMap.insert
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-- | Remove an element from the map.
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remove :: Key -> Container a -> Container a
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remove = IntMap.delete
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-- | Return the list of values in the map.
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elems :: Container a -> [a]
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elems = IntMap.elems
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-- | Return the list of keys in the map.
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keys :: Container a -> [Key]
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keys = IntMap.keys
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-- | Create a map from an association list.
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fromAssocList :: [(Key, a)] -> Container a
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fromAssocList = IntMap.fromList
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-- | Add or update two elements of the map.
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addTwo :: Key -> a -> Key -> a -> Container a -> Container a
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addTwo k1 v1 k2 v2 = add k1 v1 . add k2 v2
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-- | Compute the name of an element in a container.
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nameOf :: (T.Element a) => Container a -> Key -> String
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nameOf c k = T.nameOf $ find k c
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-- | Compute the maximum name length in an Element Container.
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maxNameLen :: (T.Element a) => Container a -> Int
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maxNameLen = maximum . map (length . T.nameOf) . elems
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-- | Find an element by name in a Container; this is a very slow function.
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findByName :: (T.Element a, Monad m) =>
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              Container a -> String -> m a
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findByName c n =
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    let all_elems = elems c
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        result = filter ((== n) . T.nameOf) all_elems
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    in case result of
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         [item] -> return item
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         _ -> fail $ "Wrong number of elems found with name " ++ n