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{-# LANGUAGE TemplateHaskell #-}

{-| Implementation of the Ganeti Query2 language.

 -}

{-

Copyright (C) 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.Query2

    ( Filter(..)

    , Query(..)

    , QueryResult(..)

    , QueryFields(..)

    , QueryFieldsResult(..)

    , FieldDefinition(..)

    , ResultEntry(..)

    ) where

import Text.JSON.Types

import Text.JSON

import qualified Ganeti.Constants as C

import Ganeti.THH

-- * THH declarations, that require ordering.

-- | Status of a query field.

$(declareIADT "ResultStatus"

  [ ("RSNormal",  'C.rsNormal )

  , ("RSUnknown", 'C.rsUnknown )

  , ("RSNoData",  'C.rsNodata )

  , ("RSUnavail", 'C.rsUnavail )

  , ("RSOffline", 'C.rsOffline )

  ])

$(makeJSONInstance ''ResultStatus)

-- | Type of a query field.

$(declareSADT "FieldType"

  [ ("QFTUnknown",   'C.qftUnknown )

  , ("QFTText",      'C.qftText )

  , ("QFTBool",      'C.qftBool )

  , ("QFTNumber",    'C.qftNumber )

  , ("QFTUnit",      'C.qftUnit )

  , ("QFTTimestamp", 'C.qftTimestamp )

  , ("QFTOther",     'C.qftOther )

  ])

$(makeJSONInstance ''FieldType)

-- | Supported items on which Query2 works.

$(declareSADT "ItemType"

  [ ("QRCluster",  'C.qrCluster )

  , ("QRInstance", 'C.qrInstance )

  , ("QRNode",     'C.qrNode )

  , ("QRLock",     'C.qrLock )

  , ("QRGroup",    'C.qrGroup )

  , ("QROs",       'C.qrOs )

  , ("QRJob",      'C.qrJob )

  , ("QRExport",   'C.qrExport )

  ])

$(makeJSONInstance ''ItemType)

-- * Main Query2 queries and responses.

-- | Query2 query.

data Query = Query ItemType Fields (Maybe Filter)

-- | Query2 result.

data QueryResult = QueryResult [ FieldDefinition ] [ ResultEntry ]

-- | Query2 Fields query.

-- (to get supported fields names, descriptions, and types)

data QueryFields = QueryFields ItemType Fields

-- | Query2 Fields result.

data QueryFieldsResult = QueryFieldsResult [ FieldDefinition ]

-- * Sub data types for query2 queries and responses.

-- | List of requested fields.

type Fields = [ String ]

-- | Query2 filter expression.

data Filter

    = AndFilter [ Filter ] -- ^ & [<expression>, ...]

    | OrFilter [ Filter ] -- ^ | [<expression>, ...]

    | NotFilter Filter -- ^ ! <expression>

    | TrueFilter FilterField -- ^ ? <field>

    | EqualFilter FilterField FilterValue -- ^ (=|!=) <field> <value>

    | LessThanFilter FilterField FilterValue -- ^ < <field> <value>

    | GreaterThanFilter FilterField FilterValue -- ^ > <field> <value>

    | LEThanFilter FilterField FilterValue -- ^ <= <field> <value>

    | GEThanFilter FilterField FilterValue -- ^ >= <field> <value>

    | RegexpFilter FilterField FilterRegexp -- ^ =~ <field> <regexp>

    | ContainsFilter FilterField FilterValue -- ^ =[] <list-field> <value>

-- | Field name to filter on.

type FilterField = String

-- | Value to compare the field value to, for filtering purposes.

type FilterValue = String

-- | Regexp to apply to the filter value, for filteriong purposes.

type FilterRegexp = String

-- | Definition of a field.

data FieldDefinition = FieldDefinition FieldName FieldTitle FieldType FieldDoc

-- | Name of a field.

type FieldName = String

-- | Title of a field, when represented in tabular format.

type FieldTitle = String

-- | Human redable description of a field.

type FieldDoc = String

--- | Single field entry result.

data ResultEntry = ResultEntry ResultStatus (Maybe ResultValue)

-- | Value of a field, in json encoding.

-- (its type will be depending on ResultStatus and FieldType)

type ResultValue = JSValue